SECONDARY CELL GROUP IN DORMANT STATE WITH DATA TRAFFIC DISABLED

Abstract

In an aspect, a BS configured as a master node (MN) of a master cell group (MCG) acts as a relay for at least downlink C-Plane communications from a secondary node (SN) of a secondary cell group (SCG) to a UE during a period where the SCG is dormant with downlink and uplink U-Plane communications disabled.

Description

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

Aspects of the disclosure relate generally to wireless communications, and more particularly to a secondary cell group (SCG) in a dormant state with data traffic (e.g., uplink and downlink U-Plane communications) disabled.

2. Description of the Related Art

Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (1G), a second-generation (2G) digital wireless phone service (including interim 2.5G networks), a third-generation (3G) high speed data, Internet-capable wireless service and a fourth-generation (4G) service (e.g., LTE or WiMax). There are presently many different types of wireless communication systems in use, including cellular and personal communications service (PCS) systems. Examples of known cellular systems include the cellular analog advanced mobile phone system (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), the Global System for Mobile access (GSM) variation of TDMA, etc.

A fifth generation (5G) wireless standard, referred to as New Radio (NR), enables higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The 5G standard, according to the Next Generation Mobile Networks Alliance, is designed to provide data rates of several tens of megabits per second to each of tens of thousands of users, with 1 gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large wireless sensor deployments. Consequently, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards.

SUMMARY

The following presents a simplified summary relating to one or more aspects disclosed herein. Thus, the following summary should not be considered an extensive overview relating to all contemplated aspects, nor should the following summary be considered to identify key or critical elements relating to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the following summary has the sole purpose to present certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below.

An aspect is directed to a method of operating a user equipment (UE), comprising receiving, while a secondary cell group (SCG) is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications from a secondary node (SN) associated with the SCG over one or more cells of a master cell group (MCG), and transmitting, while the SCG is associated with the dormant state, uplink C-Plane communications through a primary secondary cell (PSCell) of the SCG to the SN.

Another aspect is directed to a method of operating a base station configured as a master node (MN) of a master cell group (MCG) for a user equipment (UE), comprising receiving, from a secondary node (SN) of a secondary cell group (SCG) of the UE while the SCG of the UE is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and transmitting the downlink C-Plane communications to the UE.

Another aspect is directed to a method of operating a base station configured as a secondary node (SN) of a secondary cell group (SCG) for a user equipment (UE), comprising transmitting, to a master node (MN) of a master cell group (MCG) of the UE while the SCG is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and receiving, over a primary secondary cell (PSCell) of the SCG while the SCG is associated with the dormant state, uplink C-Plane communications from the UE.

Another aspect is directed to a user equipment (UE), comprising means for receiving, while a secondary cell group (SCG) is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications from a secondary node (SN) associated with the SCG over one or more cells of a master cell group (MCG), and means for transmitting, while the SCG is associated with the dormant state, uplink C-Plane communications through a primary secondary cell (PSCell) of the SCG to the SN.

Another aspect is directed to a base station configured as a master node (MN) of a master cell group (MCG) for a user equipment (UE), comprising means for receiving, from a secondary node (SN) of a secondary cell group (SCG) of the UE while the SCG of the UE is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and means for transmitting the downlink C-Plane communications to the UE.

Another aspect is directed to a base station configured as a secondary node (SN) of a secondary cell group (SCG) for a user equipment (UE), comprising means for transmitting, to a master node (MN) of a master cell group (MCG) of the UE while the SCG is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and means for receiving, over a primary secondary cell (PSCell) of the SCG while the SCG is associated with the dormant state, uplink C-Plane communications from the UE.

Another aspect is directed to a user equipment (UE), comprising a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to receive, while a secondary cell group (SCG) is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications from a secondary node (SN) associated with the SCG over one or more cells of a master cell group (MCG), and transmit, while the SCG is associated with the dormant state, uplink C-Plane communications through a primary secondary cell (PSCell) of the SCG to the SN.

Another aspect is directed to a base station configured as a master node (MN) of a master cell group (MCG) for a user equipment (UE), comprising a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to receive, from a secondary node (SN) of a secondary cell group (SCG) of the UE while the SCG of the UE is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and transmit the downlink C-Plane communications to the UE.

Another aspect is directed to a base station configured as a secondary node (SN) of a secondary cell group (SCG) for a user equipment (UE), comprising a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to transmit, to a master node (MN) of a master cell group (MCG) of the UE while the SCG is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and receive, over a primary secondary cell (PSCell) of the SCG while the SCG is associated with the dormant state, uplink C-Plane communications from the UE.

Another aspect is directed to a non-transitory computer-readable medium containing instructions stored thereon, for causing at least one processor in a user equipment (UE) to receive, while a secondary cell group (SCG) is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications from a secondary node (SN) associated with the SCG over one or more cells of a master cell group (MCG), and transmit, while the SCG is associated with the dormant state, uplink C-Plane communications through a primary secondary cell (PSCell) of the SCG to the SN.

Another aspect is directed to a non-transitory computer-readable medium containing instructions stored thereon, for causing at least one processor in a base station configured as a master node (MN) of a master cell group (MCG) for a user equipment (UE) to receive, from a secondary node (SN) of a secondary cell group (SCG) of the UE while the SCG of the UE is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and transmit the downlink C-Plane communications to the UE.

Another aspect is directed to a non-transitory computer-readable medium containing instructions stored thereon, for causing at least one processor in a base station configured as a secondary node (SN) of a secondary cell group (SCG) for a user equipment (UE) to transmit, to a master node (MN) of a master cell group (MCG) of the UE while the SCG is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE, and receive, over a primary secondary cell (PSCell) of the SCG while the SCG is associated with the dormant state, uplink C-Plane communications from the UE.

Other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to aid in the description of various aspects of the disclosure and are provided solely for illustration of the aspects and not limitation thereof.

FIG. 1 illustrates an exemplary wireless communications system, according to various aspects.

FIGS. 2A and 2B illustrate example wireless network structures, according to various aspects.

FIGS. 3A to 3C are simplified block diagrams of several sample aspects of components that may be employed in wireless communication nodes and configured to support communication as taught herein.

FIGS. 4A and 4B are diagrams illustrating examples of frame structures and channels within the frame structures, according to aspects of the disclosure.

FIG. 5A depicts a wireless communications system 500A showing user plane connectivity supporting dual connectivity for a UE 502 (which may correspond to any of the above-described UEs, such as UE 302).

FIG. 5B depicts a wireless communications system 500B showing control plane connectivity supporting dual connectivity for the UE 502.

FIG. 6 illustrates an exemplary process of wireless communication, according to aspects of the disclosure.

FIG. 7 illustrates an exemplary process of wireless communication, according to aspects of the disclosure.

FIG. 8 illustrates an exemplary process of wireless communication, according to aspects of the disclosure.

FIGS. 9-10 illustrate example implementations of the processes of FIGS. 6-8 in accordance with aspects of the disclosure.

DETAILED DESCRIPTION

Aspects of the disclosure are provided in the following description and related drawings directed to various examples provided for illustration purposes. Alternate aspects may be devised without departing from the scope of the disclosure. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.

The words “exemplary” and/or “example” are used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” and/or “example” is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term “aspects of the disclosure” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation.

Those of skill in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description below may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the particular application, in part on the desired design, in part on the corresponding technology, etc.

Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., application specific integrated circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. Additionally, the sequence(s) of actions described herein can be considered to be embodied entirely within any form of non-transitory computer-readable storage medium having stored therein a corresponding set of computer instructions that, upon execution, would cause or instruct an associated processor of a device to perform the functionality described herein. Thus, the various aspects of the disclosure may be embodied in a number of different forms, all of which have been contemplated to be within the scope of the claimed subject matter. In addition, for each of the aspects described herein, the corresponding form of any such aspects may be described herein as, for example, “logic configured to” perform the described action.

As used herein, the terms “user equipment” (UE) and “base station” are not intended to be specific or otherwise limited to any particular radio access technology (RAT), unless otherwise noted. In general, a UE may be any wireless communications device (e.g., a mobile phone, router, tablet computer, laptop computer, tracking device, wearable (e.g., smartwatch, glasses, augmented reality (AR)/virtual reality (VR) headset, etc.), vehicle (e.g., automobile, motorcycle, bicycle, etc.), Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communications network. A UE may be mobile or may (e.g., at certain times) be stationary, and may communicate with a radio access network (RAN). As used herein, the term “UE” may be referred to interchangeably as an “access terminal” or “AT,” a “client device,” a “wireless device,” a “subscriber device,” a “subscriber terminal,” a “subscriber station,” a “user terminal” or UT, a “mobile terminal,” a “mobile station,” or variations thereof. Generally, UEs can communicate with a core network via a RAN, and through the core network the UEs can be connected with external networks such as the Internet and with other UEs. Of course, other mechanisms of connecting to the core network and/or the Internet are also possible for the UEs, such as over wired access networks, wireless local area network (WLAN) networks (e.g., based on IEEE 802.11, etc.) and so on.

A base station may operate according to one of several RATs in communication with UEs depending on the network in which it is deployed, and may be alternatively referred to as an access point (AP), a network node, a NodeB, an evolved NodeB (eNB), a New Radio (NR) Node B (also referred to as a gNB or gNodeB), etc. In addition, in some systems a base station may provide purely edge node signaling functions while in other systems it may provide additional control and/or network management functions. In some systems, a base station may correspond to a Customer Premise Equipment (CPE) or a road-side unit (RSU). In some designs, a base station may correspond to a high-powered UE (e.g., a vehicle UE or VUE) that may provide limited certain infrastructure functionality. A communication link through which UEs can send signals to a base station is called an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which the base station can send signals to UEs is called a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein the term traffic channel (TCH) can refer to either an UL/reverse or DL/forward traffic channel.

The term “base station” may refer to a single physical transmission-reception point (TRP) or to multiple physical TRPs that may or may not be co-located. For example, where the term “base station” refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to a cell of the base station. Where the term “base station” refers to multiple co-located physical TRPs, the physical TRPs may be an array of antennas (e.g., as in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming) of the base station. Where the term “base station” refers to multiple non-co-located physical TRPs, the physical TRPs may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRPs may be the serving base station receiving the measurement report from the UE and a neighbor base station whose reference RF signals the UE is measuring. Because a TRP is the point from which a base station transmits and receives wireless signals, as used herein, references to transmission from or reception at a base station are to be understood as referring to a particular TRP of the base station.

An “RF signal” comprises an electromagnetic wave of a given frequency that transports information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single “RF signal” or multiple “RF signals” to a receiver. However, the receiver may receive multiple “RF signals” corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels. The same transmitted RF signal on different paths between the transmitter and receiver may be referred to as a “multipath” RF signal.

According to various aspects, FIG. 1 illustrates an exemplary wireless communications system 100. The wireless communications system 100 (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations 102 and various UEs 104. The base stations 102 may include macro cell base stations (high power cellular base stations) and/or small cell base stations (low power cellular base stations). In an aspect, the macro cell base station may include eNBs where the wireless communications system 100 corresponds to an LTE network, or gNBs where the wireless communications system 100 corresponds to a NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

The base stations 102 may collectively form a RAN and interface with a core network 170 (e.g., an evolved packet core (EPC) or next generation core (NGC)) through backhaul links 122, and through the core network 170 to one or more location servers 172. In addition to other functions, the base stations 102 may perform functions that relate to one or more of transferring user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through the EPC/NGC) over backhaul links 134, which may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. In an aspect, one or more cells may be supported by a base station 102 in each coverage area 110. A “cell” is a logical communication entity used for communication with a base station (e.g., over some frequency resource, referred to as a carrier frequency, component carrier, carrier, band, or the like), and may be associated with an identifier (e.g., a physical cell identifier (PCI), a virtual cell identifier (VCI)) for distinguishing cells operating via the same or a different carrier frequency. In some cases, different cells may be configured according to different protocol types (e.g., machine-type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of UEs. Because a cell is supported by a specific base station, the term “cell” may refer to either or both the logical communication entity and the base station that supports it, depending on the context. In some cases, the term “cell” may also refer to a geographic coverage area of a base station (e.g., a sector), insofar as a carrier frequency can be detected and used for communication within some portion of geographic coverage areas 110.

While neighboring macro cell base station 102 geographic coverage areas 110 may partially overlap (e.g., in a handover region), some of the geographic coverage areas 110 may be substantially overlapped by a larger geographic coverage area 110. For example, a small cell base station 102′ may have a coverage area 110′ that substantially overlaps with the coverage area 110 of one or more macro cell base stations 102. A network that includes both small cell and macro cell base stations may be known as a heterogeneous network. A heterogeneous network may also include home eNBs (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG).

The communication links 120 between the base stations 102 and the UEs 104 may include UL (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links 120 may be through one or more carrier frequencies. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

The wireless communications system 100 may further include a wireless local area network (WLAN) access point (AP) 150 in communication with WLAN stations (STAs) 152 via communication links 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in an unlicensed frequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may perform a clear channel assessment (CCA) or listen before talk (LBT) procedure prior to communicating in order to determine whether the channel is available.

The small cell base station 102′ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell base station 102′ may employ LTE or NR technology and use the same 5 GHz unlicensed frequency spectrum as used by the WLAN AP 150. The small cell base station 102′, employing LTE/5G in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network. NR in unlicensed spectrum may be referred to as NR-U. LTE in an unlicensed spectrum may be referred to as LTE-U, licensed assisted access (LAA), or MulteFire.

The wireless communications system 100 may further include a millimeter wave (mmW) base station 180 that may operate in mmW frequencies and/or near mmW frequencies in communication with a UE 182. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in this band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW/near mmW radio frequency band have high path loss and a relatively short range. The mmW base station 180 and the UE 182 may utilize beamforming (transmit and/or receive) over a mmW communication link 184 to compensate for the extremely high path loss and short range. Further, it will be appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or near mmW and beamforming. Accordingly, it will be appreciated that the foregoing illustrations are merely examples and should not be construed to limit the various aspects disclosed herein.

Transmit beamforming is a technique for focusing an RF signal in a specific direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omni-directionally). With transmit beamforming, the network node determines where a given target device (e.g., a UE) is located (relative to the transmitting network node) and projects a stronger downlink RF signal in that specific direction, thereby providing a faster (in terms of data rate) and stronger RF signal for the receiving device(s). To change the directionality of the RF signal when transmitting, a network node can control the phase and relative amplitude of the RF signal at each of the one or more transmitters that are broadcasting the RF signal. For example, a network node may use an array of antennas (referred to as a “phased array” or an “antenna array”) that creates a beam of RF waves that can be “steered” to point in different directions, without actually moving the antennas. Specifically, the RF current from the transmitter is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling to suppress radiation in undesired directions.

Transmit beams may be quasi-collocated, meaning that they appear to the receiver (e.g., a UE) as having the same parameters, regardless of whether or not the transmitting antennas of the network node themselves are physically collocated. In NR, there are four types of quasi-collocation (QCL) relations. Specifically, a QCL relation of a given type means that certain parameters about a second reference RF signal on a second beam can be derived from information about a source reference RF signal on a source beam. Thus, if the source reference RF signal is QCL Type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, average delay, and delay spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type C, the receiver can use the source reference RF signal to estimate the Doppler shift and average delay of a second reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type D, the receiver can use the source reference RF signal to estimate the spatial receive parameter of a second reference RF signal transmitted on the same channel.

In receive beamforming, the receiver uses a receive beam to amplify RF signals detected on a given channel. For example, the receiver can increase the gain setting and/or adjust the phase setting of an array of antennas in a particular direction to amplify (e.g., to increase the gain level of) the RF signals received from that direction. Thus, when a receiver is said to beamform in a certain direction, it means the beam gain in that direction is high relative to the beam gain along other directions, or the beam gain in that direction is the highest compared to the beam gain in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) of the RF signals received from that direction.

Receive beams may be spatially related. A spatial relation means that parameters for a transmit beam for a second reference signal can be derived from information about a receive beam for a first reference signal. For example, a UE may use a particular receive beam to receive a reference downlink reference signal (e.g., synchronization signal block (SSB)) from a base station. The UE can then form a transmit beam for sending an uplink reference signal (e.g., sounding reference signal (SRS)) to that base station based on the parameters of the receive beam.

Note that a “downlink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the downlink beam to transmit a reference signal to a UE, the downlink beam is a transmit beam. If the UE is forming the downlink beam, however, it is a receive beam to receive the downlink reference signal. Similarly, an “uplink” beam may be either a transmit beam or a receive beam, depending on the entity forming it. For example, if a base station is forming the uplink beam, it is an uplink receive beam, and if a UE is forming the uplink beam, it is an uplink transmit beam.

In 5G, the frequency spectrum in which wireless nodes (e.g., base stations 102/180, UEs 104/182) operate is divided into multiple frequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In a multi-carrier system, such as 5G, one of the carrier frequencies is referred to as the “primary carrier” or “anchor carrier” or “primary serving cell” or “PCell,” and the remaining carrier frequencies are referred to as “secondary carriers” or “secondary serving cells” or “SCells.” In carrier aggregation, the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) utilized by a UE 104/182 and the cell in which the UE 104/182 either performs the initial radio resource control (RRC) connection establishment procedure or initiates the RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels, and may be a carrier in a licensed frequency (however, this is not always the case). A secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once the RRC connection is established between the UE 104 and the anchor carrier and that may be used to provide additional radio resources. In some cases, the secondary carrier may be a carrier in an unlicensed frequency. The secondary carrier may contain only necessary signaling information and signals, for example, those that are UE-specific may not be present in the secondary carrier, since both primary uplink and downlink carriers are typically UE-specific. This means that different UEs 104/182 in a cell may have different downlink primary carriers. The same is true for the uplink primary carriers. The network is able to change the primary carrier of any UE 104/182 at any time. This is done, for example, to balance the load on different carriers. Because a “serving cell” (whether a PCell or an SCell) corresponds to a carrier frequency/component carrier over which some base station is communicating, the term “cell,” “serving cell,” “component carrier,” “carrier frequency,” and the like can be used interchangeably.

For example, still referring to FIG. 1, one of the frequencies utilized by the macro cell base stations 102 may be an anchor carrier (or “PCell”) and other frequencies utilized by the macro cell base stations 102 and/or the mmW base station 180 may be secondary carriers (“SCells”). The simultaneous transmission and/or reception of multiple carriers enables the UE 104/182 to significantly increase its data transmission and/or reception rates. For example, two 20 MHz aggregated carriers in a multi-carrier system would theoretically lead to a two-fold increase in data rate (i.e., 40 MHz), compared to that attained by a single 20 MHz carrier.

The wireless communications system 100 may further include one or more UEs, such as UE 190, that connects indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. In the example of FIG. 1, UE 190 has a D2D P2P link 192 with one of the UEs 104 connected to one of the base stations 102 (e.g., through which UE 190 may indirectly obtain cellular connectivity) and a D2D P2P link 194 with WLAN STA 152 connected to the WLAN AP 150 (through which UE 190 may indirectly obtain WLAN-based Internet connectivity). In an example, the D2D P2P links 192 and 194 may be supported with any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on.

The wireless communications system 100 may further include a UE 164 that may communicate with a macro cell base station 102 over a communication link 120 and/or the mmW base station 180 over a mmW communication link 184. For example, the macro cell base station 102 may support a PCell and one or more SCells for the UE 164 and the mmW base station 180 may support one or more SCells for the UE 164.

According to various aspects, FIG. 2A illustrates an example wireless network structure 200. For example, an NGC 210 (also referred to as a “5GC”) can be viewed functionally as control plane functions 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane functions 212, (e.g., UE gateway function, access to data networks, IP routing, etc.) which operate cooperatively to form the core network. User plane interface (NG-U) 213 and control plane interface (NG-C) 215 connect the gNB 222 to the NGC 210 and specifically to the control plane functions 214 and user plane functions 212. In an additional configuration, an eNB 224 may also be connected to the NGC 210 via NG-C 215 to the control plane functions 214 and NG-U 213 to user plane functions 212. Further, eNB 224 may directly communicate with gNB 222 via a backhaul connection 223. In some configurations, the New RAN 220 may only have one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 may communicate with UEs 204 (e.g., any of the UEs depicted in FIG. 1). Another optional aspect may include location server 230, which may be in communication with the NGC 210 to provide location assistance for UEs 204. The location server 230 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server. The location server 230 can be configured to support one or more location services for UEs 204 that can connect to the location server 230 via the core network, NGC 210, and/or via the Internet (not illustrated). Further, the location server 230 may be integrated into a component of the core network, or alternatively may be external to the core network.

According to various aspects, FIG. 2B illustrates another example wireless network structure 250. For example, an NGC 260 (also referred to as a “5GC”) can be viewed functionally as control plane functions, provided by an access and mobility management function (AMF)/user plane function (UPF) 264, and user plane functions, provided by a session management function (SMF) 262, which operate cooperatively to form the core network (i.e., NGC 260). User plane interface 263 and control plane interface 265 connect the eNB 224 to the NGC 260 and specifically to SMF 262 and AMF/UPF 264, respectively. In an additional configuration, a gNB 222 may also be connected to the NGC 260 via control plane interface 265 to AMF/UPF 264 and user plane interface 263 to SMF 262. Further, eNB 224 may directly communicate with gNB 222 via the backhaul connection 223, with or without gNB direct connectivity to the NGC 260. In some configurations, the New RAN 220 may only have one or more gNBs 222, while other configurations include one or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 may communicate with UEs 204 (e.g., any of the UEs depicted in FIG. 1). The base stations of the New RAN 220 communicate with the AMF-side of the AMF/UPF 264 over the N2 interface and the UPF-side of the AMF/UPF 264 over the N3 interface.

The functions of the AMF include registration management, connection management, reachability management, mobility management, lawful interception, transport for session management (SM) messages between the UE 204 and the SMF 262, transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE 204 and the short message service function (SMSF) (not shown), and security anchor functionality (SEAF). The AMF also interacts with the authentication server function (AUSF) (not shown) and the UE 204, and receives the intermediate key that was established as a result of the UE 204 authentication process. In the case of authentication based on a UMTS (universal mobile telecommunications system) subscriber identity module (USIM), the AMF retrieves the security material from the AUSF. The functions of the AMF also include security context management (SCM). The SCM receives a key from the SEAF that it uses to derive access-network specific keys. The functionality of the AMF also includes location services management for regulatory services, transport for location services messages between the UE 204 and the location management function (LMF) 270, as well as between the New RAN 220 and the LMF 270, evolved packet system (EPS) bearer identifier allocation for interworking with the EPS, and UE 204 mobility event notification. In addition, the AMF also supports functionalities for non-3GPP access networks.

Functions of the UPF include acting as an anchor point for intra-/inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point of interconnect to the data network (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., UL/DL rate enforcement, reflective QoS marking in the DL), UL traffic verification (service data flow (SDF) to QoS flow mapping), transport level packet marking in the UL and DL, DL packet buffering and DL data notification triggering, and sending and forwarding of one or more “end markers” to the source RAN node.

The functions of the SMF 262 include session management, UE Internet protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering at the UPF to route traffic to the proper destination, control of part of policy enforcement and QoS, and downlink data notification. The interface over which the SMF 262 communicates with the AMF-side of the AMF/UPF 264 is referred to as the N11 interface.

Another optional aspect may include a LMF 270, which may be in communication with the NGC 260 to provide location assistance for UEs 204. The LMF 270 can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server. The LMF 270 can be configured to support one or more location services for UEs 204 that can connect to the LMF 270 via the core network, NGC 260, and/or via the Internet (not illustrated).

FIGS. 3A, 3B, and 3C illustrate several sample components (represented by corresponding blocks) that may be incorporated into a UE 302 (which may correspond to any of the UEs described herein), a base station 304 (which may correspond to any of the base stations described herein), and a network entity 306 (which may correspond to or embody any of the network functions described herein, including the location server 230 and the LMF 270) to support the file transmission operations as taught herein. It will be appreciated that these components may be implemented in different types of apparatuses in different implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other apparatuses in a communication system. For example, other apparatuses in a system may include components similar to those described to provide similar functionality. Also, a given apparatus may contain one or more of the components. For example, an apparatus may include multiple transceiver components that enable the apparatus to operate on multiple carriers and/or communicate via different technologies.

The UE 302 and the base station 304 each include wireless wide area network (WWAN) transceiver 310 and 350, respectively, configured to communicate via one or more wireless communication networks (not shown), such as an NR network, an LTE network, a GSM network, and/or the like. The WWAN transceivers 310 and 350 may be connected to one or more antennas 316 and 356, respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., eNBs, gNBs), etc., via at least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wireless communication medium of interest (e.g., some set of time/frequency resources in a particular frequency spectrum). The WWAN transceivers 310 and 350 may be variously configured for transmitting and encoding signals 318 and 358 (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals 318 and 358 (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the transceivers 310 and 350 include one or more transmitters 314 and 354, respectively, for transmitting and encoding signals 318 and 358, respectively, and one or more receivers 312 and 352, respectively, for receiving and decoding signals 318 and 358, respectively.

The UE 302 and the base station 304 also include, at least in some cases, wireless local area network (WLAN) transceivers 320 and 360, respectively. The WLAN transceivers 320 and 360 may be connected to one or more antennas 326 and 366, respectively, for communicating with other network nodes, such as other UEs, access points, base stations, etc., via at least one designated RAT (e.g., WiFi, LTE-D, Bluetooth®, etc.) over a wireless communication medium of interest. The WLAN transceivers 320 and 360 may be variously configured for transmitting and encoding signals 328 and 368 (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals 328 and 368 (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the transceivers 320 and 360 include one or more transmitters 324 and 364, respectively, for transmitting and encoding signals 328 and 368, respectively, and one or more receivers 322 and 362, respectively, for receiving and decoding signals 328 and 368, respectively.

Transceiver circuitry including a transmitter and a receiver may comprise an integrated device (e.g., embodied as a transmitter circuit and a receiver circuit of a single communications device) in some implementations, may comprise a separate transmitter device and a separate receiver device in some implementations, or may be embodied in other ways in other implementations. In an aspect, a transmitter may include or be coupled to a plurality of antennas (e.g., antennas 316, 336, and 376), such as an antenna array, that permits the respective apparatus to perform transmit “beamforming,” as described herein. Similarly, a receiver may include or be coupled to a plurality of antennas (e.g., antennas 316, 336, and 376), such as an antenna array, that permits the respective apparatus to perform receive beamforming, as described herein. In an aspect, the transmitter and receiver may share the same plurality of antennas (e.g., antennas 316, 336, and 376), such that the respective apparatus can only receive or transmit at a given time, not both at the same time. A wireless communications device (e.g., one or both of the transceivers 310 and 320 and/or 350 and 360) of the apparatuses 302 and/or 304 may also comprise a network listen module (NLM) or the like for performing various measurements.

The apparatuses 302 and 304 also include, at least in some cases, satellite positioning systems (SPS) receivers 330 and 370. The SPS receivers 330 and 370 may be connected to one or more antennas 336 and 376, respectively, for receiving SPS signals 338 and 378, respectively, such as global positioning system (GPS) signals, global navigation satellite system (GLONASS) signals, Galileo signals, Beidou signals, Indian Regional Navigation Satellite System (NAVIC), Quasi-Zenith Satellite System (QZSS), etc. The SPS receivers 330 and 370 may comprise any suitable hardware and/or software for receiving and processing SPS signals 338 and 378, respectively. The SPS receivers 330 and 370 request information and operations as appropriate from the other systems, and performs calculations necessary to determine the apparatus' 302 and 304 positions using measurements obtained by any suitable SPS algorithm.

The base station 304 and the network entity 306 each include at least one network interfaces 380 and 390 for communicating with other network entities. For example, the network interfaces 380 and 390 (e.g., one or more network access ports) may be configured to communicate with one or more network entities via a wire-based or wireless backhaul connection. In some aspects, the network interfaces 380 and 390 may be implemented as transceivers configured to support wire-based or wireless signal communication. This communication may involve, for example, sending and receiving: messages, parameters, or other types of information.

The apparatuses 302, 304, and 306 also include other components that may be used in conjunction with the operations as disclosed herein. The UE 302 includes processor circuitry implementing a processing system 332 for providing functionality relating to, for example, false base station (FBS) detection as disclosed herein and for providing other processing functionality. The base station 304 includes a processing system 384 for providing functionality relating to, for example, FBS detection as disclosed herein and for providing other processing functionality. The network entity 306 includes a processing system 394 for providing functionality relating to, for example, FBS detection as disclosed herein and for providing other processing functionality. In an aspect, the processing systems 332, 384, and 394 may include, for example, one or more general purpose processors, multi-core processors, ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGA), or other programmable logic devices or processing circuitry.

The apparatuses 302, 304, and 306 include memory circuitry implementing memory components 340, 386, and 396 (e.g., each including a memory device), respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on). In some cases, the apparatuses 302, 304, and 306 may include secondary cell group (SCG) modules 342, 388 and 389, respectively. The SCG modules 342, 388 and 389 may be hardware circuits that are part of or coupled to the processing systems 332, 384, and 394, respectively, that, when executed, cause the apparatuses 302, 304, and 306 to perform the functionality described herein. Alternatively, the SCG modules 342, 388 and 389 may be memory modules (as shown in FIGS. 3A-C) stored in the memory components 340, 386, and 396, respectively, that, when executed by the processing systems 332, 384, and 394, cause the apparatuses 302, 304, and 306 to perform the functionality described herein.

The UE 302 may include one or more sensors 344 coupled to the processing system 332 to provide movement and/or orientation information that is independent of motion data derived from signals received by the WWAN transceiver 310, the WLAN transceiver 320, and/or the GPS receiver 330. By way of example, the sensor(s) 344 may include an accelerometer (e.g., a micro-electrical mechanical systems (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric pressure altimeter), and/or any other type of movement detection sensor. Moreover, the sensor(s) 344 may include a plurality of different types of devices and combine their outputs in order to provide motion information. For example, the sensor(s) 344 may use a combination of a multi-axis accelerometer and orientation sensors to provide the ability to compute positions in 2D and/or 3D coordinate systems.

In addition, the UE 302 includes a user interface 346 for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on). Although not shown, the apparatuses 304 and 306 may also include user interfaces.

Referring to the processing system 384 in more detail, in the downlink, IP packets from the network entity 306 may be provided to the processing system 384. The processing system 384 may implement functionality for an RRC layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The processing system 384 may provide RRC layer functionality associated with broadcasting of system information (e.g., master information block (MIB), system information blocks (SIBs)), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

The transmitter 354 and the receiver 352 may implement Layer-1 functionality associated with various signal processing functions. Layer-1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The transmitter 354 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an orthogonal frequency division multiplexing (OFDM) subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 302. Each spatial stream may then be provided to one or more different antennas 356. The transmitter 354 may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 302, the receiver 312 receives a signal through its respective antenna(s) 316. The receiver 312 recovers information modulated onto an RF carrier and provides the information to the processing system 332. The transmitter 314 and the receiver 312 implement Layer-1 functionality associated with various signal processing functions. The receiver 312 may perform spatial processing on the information to recover any spatial streams destined for the UE 302. If multiple spatial streams are destined for the UE 302, they may be combined by the receiver 312 into a single OFDM symbol stream. The receiver 312 then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 304. These soft decisions may be based on channel estimates computed by a channel estimator. The soft decisions are then decoded and de-interleaved to recover the data and control signals that were originally transmitted by the base station 304 on the physical channel. The data and control signals are then provided to the processing system 332, which implements Layer-3 and Layer-2 functionality.

In the UL, the processing system 332 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the core network. The processing system 332 is also responsible for error detection.

Similar to the functionality described in connection with the DL transmission by the base station 304, the processing system 332 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station 304 may be used by the transmitter 314 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the transmitter 314 may be provided to different antenna(s) 316. The transmitter 314 may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 304 in a manner similar to that described in connection with the receiver function at the UE 302. The receiver 352 receives a signal through its respective antenna(s) 356. The receiver 352 recovers information modulated onto an RF carrier and provides the information to the processing system 384.

In the UL, the processing system 384 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 302. IP packets from the processing system 384 may be provided to the core network. The processing system 384 is also responsible for error detection.

For convenience, the apparatuses 302, 304, and/or 306 are shown in FIGS. 3A-C as including various components that may be configured according to the various examples described herein. It will be appreciated, however, that the illustrated blocks may have different functionality in different designs.

The various components of the apparatuses 302, 304, and 306 may communicate with each other over data buses 334, 382, and 392, respectively. The components of FIGS. 3A-C may be implemented in various ways. In some implementations, the components of FIGS. 3A-C may be implemented in one or more circuits such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors). Here, each circuit may use and/or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality. For example, some or all of the functionality represented by blocks 310 to 346 may be implemented by processor and memory component(s) of the UE 302 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Similarly, some or all of the functionality represented by blocks 350 to 389 may be implemented by processor and memory component(s) of the base station 304 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Also, some or all of the functionality represented by blocks 390 to 396 may be implemented by processor and memory component(s) of the network entity 306 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). For simplicity, various operations, acts, and/or functions are described herein as being performed “by a UE,” “by a base station,” “by a positioning entity,” etc. However, as will be appreciated, such operations, acts, and/or functions may actually be performed by specific components or combinations of components of the UE, base station, positioning entity, etc., such as the processing systems 332, 384, 394, the transceivers 310, 320, 350, and 360, the memory components 340, 386, and 396, the SCG modules 342, 388 and 389, etc.

FIG. 4A is a diagram 400 illustrating an example of a DL frame structure, according to aspects of the disclosure. FIG. 4B is a diagram 430 illustrating an example of channels within the DL frame structure, according to aspects of the disclosure. Other wireless communications technologies may have a different frame structures and/or different channels.

LTE, and in some cases NR, utilizes OFDM on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. Unlike LTE, however, NR has an option to use OFDM on the uplink as well. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (resource block) may be 12 subcarriers (or 180 kHz). Consequently, the nominal FFT size may be equal to 128, 256, 512, 1024, or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

LTE supports a single numerology (subcarrier spacing, symbol length, etc.). In contrast NR may support multiple numerologies, for example, subcarrier spacing of 15 kHz, 30 kHz, 60 kHz, 120 kHz and 204 kHz or greater may be available. Table 1 provided below lists some various parameters for different NR numerologies.

TABLE 1
						Max. nominal
Subcarrier		slots/			Symbol	system BW
spacing	Symbols/	sub-	slots/	slot	duration	(MHz) with
(kHz)	slot	frame	frame	(ms)	(μs)	4K FFT size
15	14	1	10	1	66.7	50
30	14	2	20	0.5	33.3	100
60	14	4	40	0.25	16.7	100
120	14	8	80	0.125	8.33	400
240	14	16	160	0.0625	4.17	800

In the examples of FIGS. 4A and 4B, a numerology of 15 kHz is used. Thus, in the time domain, a frame (e.g., 10 ms) is divided into 10 equally sized subframes of 1 ms each, and each subframe includes one time slot. In FIGS. 4A and 4B, time is represented horizontally (e.g., on the X axis) with time increasing from left to right, while frequency is represented vertically (e.g., on the Y axis) with frequency increasing (or decreasing) from bottom to top.

A resource grid may be used to represent time slots, each time slot including one or more time concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)) in the frequency domain. The resource grid is further divided into multiple resource elements (REs). An RE may correspond to one symbol length in the time domain and one subcarrier in the frequency domain. In the numerology of FIGS. 4A and 4B, for a normal cyclic prefix, an RB may contain 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols (for DL, OFDM symbols; for UL, SC-FDMA symbols) in the time domain, for a total of 84 REs. For an extended cyclic prefix, an RB may contain 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain, for a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 4A, some of the REs carry DL reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS may include demodulation reference signals (DMRS) and channel state information reference signals (CSI-RS), exemplary locations of which are labeled “R” in FIG. 4A.

FIG. 4B illustrates an example of various channels within a DL subframe of a frame. The physical downlink control channel (PDCCH) carries DL control information (DCI) within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol. The DCI carries information about UL resource allocation (persistent and non-persistent) and descriptions about DL data transmitted to the UE. Multiple (e.g., up to 8) DCIs can be configured in the PDCCH, and these DCIs can have one of multiple formats. For example, there are different DCI formats for UL scheduling, for non-MIMO DL scheduling, for MIMO DL scheduling, and for UL power control.

A primary synchronization signal (PSS) is used by a UE to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a PCI. Based on the PCI, the UE can determine the locations of the aforementioned DL-RS. The physical broadcast channel (PBCH), which carries an MIB, may be logically grouped with the PSS and SSS to form an SSB (also referred to as an SS/PBCH). The MIB provides a number of RBs in the DL system bandwidth and a system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs), and paging messages.

FIG. 5A depicts a wireless communications system 500A showing user plane connectivity supporting dual connectivity for a UE 502 (which may correspond to any of the above-described UEs, such as UE 302). When configured for dual connectivity, the UE 502 may be connected to a primary or master node, referred to as a master cell group (MCG) node, and to one or more secondary nodes, referred to as secondary cell group (SCG) nodes. The MCG and SCG are referred to as cell “groups” because, as will be appreciated, a base station typically supports multiple (e.g., three) cells, and a UE (e.g., UE 502) may communicate with one or more of them (e.g., via carrier aggregation, mobility, etc.). In the example of FIG. 5A, the UE 502 is connected to a master evolved Node B (MeNB) 520A via a communication link 524, and to a secondary evolved Node B (SeNB) 520B via a communication link 528 (collectively, base stations 520). With reference to FIG. 1, the MeNB 520A may be correspond to any of the above-described BSs, such as BS 304.

The communication links 524 and 528 may include uplink (UL) (also referred to as reverse link) transmissions from the UE 502 to the base stations 520 and/or downlink (DL) (also referred to as forward link) transmissions from the base stations 520 to the UE 502. The communication links 524 and 528 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links 524 and 528 may be through one or more carrier frequencies (also referred to as “component carriers” or simply “carriers”).

In an exemplary aspect, the SeNB 520B may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the SeNB 520B may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by WLAN access points. The SeNB 520B, employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the wireless communications system 500A.

Some wireless communications systems, such as NR systems, support operation at very high and even extremely-high frequency (EHF) bands, such as millimeter wave (mmW) frequency bands (generally, wavelengths of 1 mm to 10 mm, or 30 to 300 GHz). These extremely high frequencies may support very high throughput, such as up to 6 gigabits per second (Gbps). In the wireless communications system 500A, the SeNB 520B may operate in mmW frequencies and/or near mmW frequencies in communication with a mmW and/or near mmW-capable UE (e.g., UE 502). When the SeNB 520B/UE 502 operates in mmW or near mmW frequencies, the SeNB 520B may be referred to as a mmW base station or mmW SeNB. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. Super high frequency (SHF) bands extends between 3 GHz and 30 GHz, and are also referred to as centimeter wave.

One of the challenges for wireless communication at very high or extremely high frequencies, however, is that a significant propagation loss may occur due to the high frequency. As the frequency increases, the wavelength may decrease, and the propagation loss may increase as well. At mmW frequency bands, the propagation loss may be severe. For example, the propagation loss may be on the order of 22 to 27 dB, relative to that observed in either the 2.4 GHz, or 5 GHz bands. The mmW SeNB 520B and/or the UE 502 may utilize beamforming over communication link 528 to compensate for the extremely high path loss and short range.

Transmitters (e.g., SeNB 520B/UE 502) may use beamforming to extend radio frequency (RF) signal coverage. Transmit beamforming is a technique for focusing an RF signal in a specific direction. Traditionally, when a transmitter (e.g., MeNB 520A) broadcasts an RF signal, it broadcasts the signal in all directions (omni-directionally; hence, the circular shape of PCell 522). With transmit beamforming, the transmitter (e.g., SeNB 520B) determines where a given target device (e.g., UE 502) is located (relative to the transmitter) and projects a stronger downlink RF signal in that specific direction (hence the oval shape of SCell 526), thereby providing a faster (in terms of data rate) and stronger RF signal for the receiving device(s). To change the directionality of the RF signal when transmitting, a transmitter can control the phase and relative amplitude of the RF signal at each transmission point (e.g., antenna). For example, a transmitter may use an array of antennas (referred to as a “phased array” or an “antenna array”) that creates a beam of RF waves that can be “steered” to point in different directions, without actually moving the antennas. Specifically, the RF current from the transmitter is fed to the individual antennas with the correct phase relationship so that the radio waves from the separate antennas add together to increase the radiation in a desired direction, while cancelling to suppress radiation in undesired directions.

The base stations 520/UE 502 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100 MHz) bandwidth per carrier allocated in a carrier aggregation (CA) of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The component carriers may or may not be adjacent to each other on the frequency spectrum. Allocation of carriers may be asymmetric with respect to the DL and UL (e.g., more or less carriers may be allocated for DL than for UL).

The component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as the “active carrier frequency” or the primary cell (PCell), and the secondary component carrier(s) may be referred to as secondary cell(s) (SCell(s)). In order to operate on multiple carrier frequencies, a base station 520/UE 502 is equipped with multiple receivers and/or transmitters. For example, a UE may have two receivers, Receiver 1 and Receiver 2, where Receiver 1 is a multi-band receiver that can be tuned to band (i.e., carrier frequency) X or band Y, and Receiver 2 is a one-band receiver tunable to band Z only. In this example, if the UE is being served in band X, band X would be referred to as the PCell or the active carrier frequency, and Receiver 1 would need to tune from band X to band Y (an SCell) in order to measure band Y (and vice versa). In contrast, whether the UE is being served in band X or band Y, because of the separate Receiver 2, the UE can measure band Z without interrupting the service on band X or band Y. The simultaneous transmission and/or reception of multiple carriers enables a UE 502 to significantly increase its data transmission and/or reception rates.

In carrier aggregation, one of the frequencies utilized by a base station 520 may be the PCell for the UE 502 and other frequencies utilized by the base station 520 may be SCells. For example, one of the frequencies utilized by the base station 520A may be assigned to the UE 502 as that UE's PCell, and other frequencies utilized by the base station 520A may be assigned as SCells, whereas one of the frequencies assigned to the UE 502 as an SCell may be assigned to a second UE (not shown) as that UE's PCell, and other frequencies utilized by the base station 520A, including the PCell assigned to the UE 502, may be assigned to the second UE as SCells.

Dual connectivity, however, is used to achieve carrier aggregation between different base stations, and possibly different radio access technologies (RATs), rather than different cells supported by the same base station. Dual connectivity is well-suited in heterogeneous networks (e.g., a network of macro cells and small cells), but can also be used in homogenous networks (e.g., a network of all macro cells). In the example of FIG. 5A, the UE 502 is in the PCell 522 served by the MeNB 520A and the SCell 526 served by the SeNB 520B. Although the present disclosure uses the terms “MeNB” and “SeNB,” as will be appreciated, the MeNB 520A and the SeNB 520B need not both utilize the same RAT (e.g., LTE), but rather, may utilize different RATs. For example, the MeNB 520A may be a macro cell operating according to LTE, and the SeNB 520B may be a small cell base station operating according to 5G NR.

The wireless communications system 500A may further include other network nodes such as a serving gateway (SGW) 542. The serving gateway 542 may support a user plane interface, such as a S1-U 544A/544B with base stations 520. The SGW 542 may also support a control plane interface to a mobility management entity (MME) (shown in FIG. 5B).

FIG. 5B depicts a wireless communications system 500B showing control plane connectivity supporting dual connectivity for the UE 502. In the example of FIG. 5B, the S1-MME 548 interface between the MME 550 and the MeNB 520A may be used as a control plane for controlling the dual connectivity provided to UE 502. The control plane signaling may also include an interface (not shown) between the MME 550 and the SGW 542.

In the case of dual connectivity, there may different bearer options, including a split bearer option and a secondary cell group (SCG) bearer option. For split bearers, for example, the S1-U interface 544A connection to the SGW 542 may be terminated in the MeNB 520A, and the MeNB 520A may split some of the user plane traffic toward the SeNB 520B via the X2 interface 546. In the case of SCG bearers, for example, the SeNB 520B may be directly connected to a core network (e.g., the SGW 542 of the core network via the S1-U interface 544A), while the MeNB 520A may not be not involved in the transport of user plane data for this type of bearer(s) over the Uu interface (i.e., the radio interface).

The MeNB 520A is responsible for radio resource control (RRC) layer (referred to as “layer 3” or L3) signaling for the UE 502. However, both the MeNB 520A and the SeNB 520B have different physical downlink control channels (PDCCHs) and physical downlink shared channels (PDSCHs). Data for the UE 502 is split at the packet data convergence protocol (PDCP) layer, but unlike carrier aggregation, the radio link control (RLC) layer and the medium access control (MAC) layer are different for the MeNB 520A and the SeNB 520B (the PDCP, RLC, and MAC layers are collectively referred to as “layer 2” or L2).

In multi-RAT Dual Connectivity (MR-DC) for 3GPP Rel. 17, deactivation/suspension of the SCG during periods of bursty traffic, UE overheating and/or special traffic types (e.g. VOIP) may be implemented. The goal of SCG suspension is to reduce activation/deactivation latency and to save power at the UE. In some cases, SCG suspension is preferred over deactivation due to minimal activation delay in comparison with SCG activation delay of over 79 ms. To address this issue, the notion of “SCG dormancy” has been considered as an SCG suspension mode.

Some of the features in carrier aggregation (CA) SCell Dormancy which were standardized in 3GPP NR Rel. 16 can be leveraged for SCG dormancy while others may not. In CA SCell Dormancy, SCells are in a dormant state with no DL monitoring or UL channel transmission. In CA SCell Dormancy, RRM, RLM and L1 measurements are allowed and the measurement reporting is performed through the primary secondary cell (PSCell) of the SCG which remains in an active state.

During SCG dormancy, measurements can be made on PSCell or SCells in SCG dormancy. During SCG dormancy, the MCG is not dormant, so even though reporting of some measurements (e.g., L3 measurements) could be performed through MCG, various problems may occur if such an implementation is attempted, e.g.:

• • Synchronization: MCG and SCG might not be synchronized, so the L1 measurements could be inaccurate.
  • Extensive Modification: The modification may be required to send L1 measurements between the MN and SN would be significant.
  • Latency: The latency involved especially for L1 measurements could be prohibitive.

In some designs, during SCG dormancy, the PSCell may be characterized as being “semi-dormant”. Some measurement reporting (e.g., L1 measurements for PSCell and SCell) can be performed using the PSCell of the SCG using PUCCH/PUSCH. DL channels (PDCCH/PDSCH) may also be activated on the PSCell. When PSCell is used for measurement reporting, some power consumption is traded off with performance and reporting latency during SCG dormancy. This may reduce the latency incurred and improve performance when bringing SCG out of dormancy especially, in scenarios where the dormant bandwidth (BW) and non-dormant BW(s) overlap.

Frequency resources associated with a PSCell of an SCG can be configured in different ways. In a first scenario (“Scenario 1”), each cell of the MCG is associated with FR1, and each cell of the SCG (including the PSCell) is associated with FR2. Scenario 1, measurements on the PSCell are expected to be highly correlated to those on SCell(s), such that measurements by the UE on the PSCell may be sufficient to maintain power control, beam associations, and/or timing on the SCell(s) during SCG dormancy. In a second scenario (“Scenario 2”), each cell of the MCG is associated with FR1, each cell SCell of the SCG is associated with FR2, and the PSCell of the SCG is associated with FR1. In Scenario 2, measurements no the PSCell are likely uncorrelated to those on SCells, such that measurements are performed on both PSCell and SCell(s) during SCG dormancy. For example, in Scenario 2, the QCL/spatial relationships on the PSCell and SCell(s) could be vastly different.

One or more aspects of the disclosure are thereby directed to SCG dormancy whereby uplink and downlink user plane (U-plane) communications are disabled over the SCG altogether, while uplink C-Plane communications remain permitted to the PSCell. In this case, downlink C-Plane communications associated with the SCG may be communicated to the UE via the MCG in accordance with backhaul signaling between a BS configured as a master node (MN) for the MCG and a BS configured as a secondary node (SN) for the SCG. Such aspects may provide various technical advantages, such as reducing power consumption at the UE during SCG dormancy while also facilitating various management functions associated with the SCG such that the SCG can be more quickly activated upon exiting SCG dormancy.

FIG. 6 illustrates an exemplary process 600 of wireless communication, according to aspects of the disclosure. In an aspect, the process 600 may be performed by a UE, such as any of the UEs described above (e.g., UE 302, etc.).

At 610, UE 302 (e.g., receiver 312, receiver 322, etc.) receives, while a secondary cell group (SCG) is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications from a secondary node (SN) associated with the SCG over one or more cells of a master cell group (MCG). In some designs, the downlink C-Plane communications may include control information related to one or more of a beam update, a timing adjustment and/or a power control command associated with one or more cells of the SCG. In some designs, the control information may be based on a measurement report (e.g., reported to MCG or to PSCell of SCG via PUCCH communication) associated with one or more reference signals (e.g., one or more L1 reference signals) received at UE 302 over the one or more cells of the SCG.

At 620, UE 302 (e.g., transmitter 314, transmitter 324, etc.) transmits, while the SCG is associated with the dormant state, uplink C-Plane communications through a primary secondary cell (PSCell) of the SCG to the SN. In some designs, the uplink C-Plane communications may include one or more PUCCH communications. As will be appreciated, even though downlink and uplink U-Plane communications are disabled over SCG during SCG dormancy, uplink C-Plane communications are still permitted over SCG during SCG dormancy and downlink C-Plane communications can be sent through the MCG.

FIG. 7 illustrates an exemplary process 700 of wireless communication, according to aspects of the disclosure. In an aspect, the process 700 may be performed by a BS, such as any of the BSs described above (e.g., BS 304, etc.). More specifically, the process 700 of FIG. 7 is performed by a BS (e.g., MeNB 520A) configured as a MN of a MCG for a UE, such as the UE performing the process 600 of FIG. 6.

At 710, the MN (e.g., network interface(s) 380, receiver 352, receiver 362, etc.) receives, from a secondary node (SN) of a secondary cell group (SCG) of the UE while the SCG of the UE is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE. In some designs, the downlink C-Plane communications are received via backhaul signaling (e.g., over a wired backhaul such as the X2 interface 546 depicted in FIG. 5B, or over a wireless backhaul connection). In some designs, the downlink C-Plane communications may include control information related to one or more of a beam update, a timing adjustment and/or a power control command associated with one or more cells of the SCG. In some designs, the control information may be based on a measurement report (e.g., reported to MCG or to PSCell of SCG via PUCCH communication) associated with one or more reference signals (e.g., one or more L1 reference signals) received at UE 302 over the one or more cells of the SCG.

At 720, the MN (e.g., transmitter 354, transmitter 364, etc.) transmits the downlink C-Plane communications to the UE.

Referring to FIG. 7, in some designs, the MN may perform a similar relaying function for at least some uplink C-Plane communications. For example, the MN may receive one or more reports (e.g., a beam failure report from the UE that indicates beam failure on at least one cell of the SCG, L3 measurement report based on L3 measurements on one or more cells of the SCG, etc.), and then relay the report(s) to the SN (e.g., via X2 interface 546).

FIG. 8 illustrates an exemplary process 800 of wireless communication, according to aspects of the disclosure. In an aspect, the process 800 may be performed by a BS, such as any of the BSs described above (e.g., BS 304, etc.). More specifically, the process 800 of FIG. 8 is performed by a BS (e.g., SeNB 520B) configured as a SN of a SCG for a UE, such as the UE performing the process 600 of FIG. 6.

At 810, the SN (e.g., network interface(s) 380, transmitter 354, transmitter 364, etc.) transmits, to a master node (MN) of a master cell group (MCG) of the UE while the SCG is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE. In some designs, the downlink C-Plane communications are transmitted via backhaul signaling (e.g., over a wired backhaul such as the X2 interface 546 depicted in FIG. 5B, or over a wireless backhaul connection). In some designs, the downlink C-Plane communications may include control information related to one or more of a beam update, a timing adjustment and/or a power control command associated with one or more cells of the SCG. In some designs, the control information may be based on a measurement report (e.g., received via relaying from the MCG, or received directly at the SN via PSCell of SCG over PUCCH communication) associated with one or more reference signals (e.g., one or more L1 reference signals) transmitted by the SN over the one or more cells of the SCG.

At 820, the SN (e.g., receiver 352, receiver 362, etc.) receives, over a primary secondary cell (PSCell) of the SCG while the SCG is associated with the dormant state, uplink C-Plane communications from the UE. In some designs, the uplink C-Plane communications may include one or more PUCCH communications. As will be appreciated, even though downlink and uplink U-Plane communications are disabled over SCG during SCG dormancy, uplink C-Plane communications are still permitted over SCG during SCG dormancy and downlink C-Plane communications can be sent through the MCG.

In some designs, the processes of FIGS. 6-8 may be used to facilitate beam management associated with the cells of the SCG during SCG dormancy without the UE being required to allocate power for monitoring of downlink C-Plane communications directly from the SCG. For example, radio link monitoring (RLM) may be used to detect radio link failure associated with SCG cell(s), and beam failure detection (BFD) may be used to detect beam failure associated with SCG cell(s). In some designs, L1 measurements of L1 reference signals from SCG cell(s) may be used to track and maintain a threshold beam quality during SCG dormancy. In some designs, SRS transmissions to SCG cell(s) may be used to track and maintain timing and uplink transmission power. In some designs, beam update, timing adjustment and power control procedures for SCG cell(s) during SGC dormancy will enable fast transition from SCG dormancy state to SCG active state, especially for scenarios with overlapping dormant and active BWP. In some designs, beam update, timing adjustment and power control procedures for SCG cell(s) during SCG dormancy will help to avoid the need for frequent RACH procedures on the PSCell.

Referring to FIGS. 6-8, in some designs, the SN may transmit, while the SCG is associated with the dormant state, one or more reference signals from one or more cells of the SCG. The UE may receive and measure the one or more reference signals and perform measurements thereon. For example, the UE may perform one or more radio resource monitoring (RRM) measurements, one or more radio link monitoring (RLM) measurements (e.g., by contrast, in some current systems RLM is only applied to the active BWP, rather than a dormant BWP of a PSCell where DL traffic is disabled), one or more beam failure detection (BFD) measurements, a combination thereof. In some designs, the SCG is configured in accordance with Scenario 2, whereby the PSCell of the SCG is associated with a first bandwidth part (BW) (e.g., FR1 or a special dormant BW separate from FR2) and one or more secondary cells (SCells) of the SCG are associated with a second BW (e.g., FR2) that is different than the first BW, and the one or more measurements comprise BFD measurements on both the PSCell and the one or more SCells. In some designs, the UE may detect beam failure on at least one cell of the SCG, and UE may transmit (e.g., via PUCCH communication) a beam failure report (e.g., which may identify the best measured beam) to the MCG (e.g., which may then relay the beam failure report to the SN) or to the PSCell of the SN directly (e.g., via RACH). In some designs, the beam failure report may be communicated via RRC signaling, MAC-CE signaling, or DCI signaling. In some designs, the UE may later receive, from the SN of the SCG in association with an exit of the SCG from the dormant state, an indication of whether to perform beam failure recovery (BFR) on the at least one cell of the SCG. In some designs (e.g., for Scenario 1), RLM and BFD may be performed only for the PSCell of the SCG during SCG dormancy (i.e., not the SCell(s) of the SCG). In other designs (e.g., for Scenario 2), BFD may be performed on the PSCell of the SGC as well as the SCell(s) of the SCG.

Referring to FIGS. 6-8, in some designs, the measurement signals transmitted by the SN and measured by the UE may include L1 reference signals. In some designs, the L1 reference signals may include one or more periodic, semi-periodic or aperiodic channel state information reference signals (CSI-RSs), one or more beam failure detection reference signals (BFD-RS), one or more aperiodic tracking reference signals (TRSs), or a combination thereof. In some designs, the L1 measurements performed by the UE may include L1-RSRP measurement(s), CQI measurement(s), or a combination thereof. In some designs, the particular combination of L1 reference signal(s) targeted for measurement may be implementation specific. In some designs, the UE may transmit a measurement report based on the one or more L1 measurements to a SN of the SCG. In some designs, L1 measurements may be performed on the PSCell only, while in other designs L1 measurements may be performed on the PSCell and SCell(s).

Referring to FIGS. 6-8, in some designs, L3 measurements may also be performed on one or more cells of the SCG while the SCG is associated with the dormant state. In some designs, the UE may transmit an L3 measurement report based on the L3 measurements to the MCG. By contrast, in some designs, the L1 measurement report is reported directly to the SN rather than being relayed via the MN (e.g., because the current standard does not support cross-group L1 measurement reporting due to its slow nature). In some designs, L1 SRS transmissions (e.g., periodic, semi-periodic or aperiodic SRSs) are used for UL beam management and timing tracking of SCG cell(s), especially in scenarios without beam correspondence, cannot be sent over MCG.

Referring to FIGS. 6-8, in some designs, the UE may transmit L1 measurement reports for the PSCell and SCell(s) of the SCG to the SN using PUCCH resources. In some designs, the UE may transmit SRS to the SN directly (e.g., rather than to the MN for indirect measurement and reporting). In some designs, the PUCCH communications from the UE may be multiplexed with SRS to improve UL transmission efficiency.

Referring to FIGS. 6-8, in some designs, the UE may receive and measure the L1 reference signals directly from the SN over the PSCell and/or SCell(s). The L1 measurements may be reported to the SN (e.g., indirectly via the MCG or directly via PUCCH) to facilitate beam updates, timing adjustment and power control commands. Such control commands are typically signaled in the PDCCH and/or PDSCH. However, in aspects of the disclosure, such control commands may instead be relayed to the UE via the MN (e.g., via RRC signaling, MAC-CE signaling, DCI signaling, etc.) rather than directly transmitted to the UE via the SN while the SCG is dormant. In some designs, a “special dormant” DL/UL BWP may be established for the PSCell which would be different from that used by the other SCell(s) to improve PDCCH/PUCCH performance.

FIG. 9 illustrates an example implementation 900 of the processes 600-800 of FIGS. 6-8 in accordance with aspects of the disclosure.

Referring to FIG. 9, at 902, an SCG associated with a UE is in a dormant state with UL and DL U-Plane communications disabled over SCG, and with DL C-Plane communications being relayed through the MCG. During the SCG dormancy, at 904, the SN transmits a CSI-RS (e.g., a periodic CSI-RS (P-CSI-RS) or an aperiodic CSI-RS (A-CSI-RS)) on one or more cells of the SCG, which is received by the UE on the PSCell during a periodic DL monitoring window 906. In particular, UE 302 performs DL beam measurements on the CSI-RS during the periodic DL monitoring window 906. At 908, UE 302 transmits a DL beam measurement report to the SN via PUCCH on the PSCell. The PUCCH communication at 908 may optionally be multiplexed with SRS as noted above. At 910, the SN selects a downlink transmit beam and determines whether to adjust any parameters based on the DL beam measurement report. At 912, because there are no active DL channels for direct C-Plane traffic from the SN to UE 302, the SN transmits a transmission configuration indicator (TCI) specifying one or more parameter changes to the MN (e.g., via X2 interface). At 914, the MN then transmits the TCI to the UE via one or more cells of the MCG. At 916, UE 302 modifies its TCI state based on the TCI. At this point, the UE ACKs the TCI via the MN (918-920) or via direct transmission to the SN via PUCCH over PSCell (922). In some designs, for ACKs sent through the PUCCH or MCG, the K1 values may be set to accommodate the long delays of sending PDSCH with TCI states over MCG or sending the ACK on the PUCCH. In some designs, the TCI is sent to the UE via the MN over RRC signaling, MAC-CE signaling, or DCI signaling.

FIG. 10 illustrates an example implementation 900 of the processes 600-800 of FIGS. 6-8 in accordance with aspects of the disclosure.

Referring to FIG. 10, at 1002, an SCG associated with a UE is in a dormant state with UL and DL U-Plane communications disabled over SCG, and with DL C-Plane communications being relayed through the MCG. During the SCG dormancy, at 1004, the SN transmits a CSI-RS (e.g., P-CSI-RS or A-CSI-RS) on one or more cells of the SCG, which is received by the UE on the PSCell during a periodic DL monitoring window 1006. In particular, UE 302 performs DL beam measurements on the CSI-RS during the periodic DL monitoring window 1006. At 1008, UE 302 transmits a DL beam measurement report to the SN via PUCCH on the PSCell. The PUCCH communication at 1008 may optionally be multiplexed with SRS as noted above. At 1010, the SN measures the UL beam associated with the PUCCH and/or the (optional) SRS, selects a UL transmit beam and determines whether to adjust any parameters based on the UL beam measurements. At 1012, because there are no active DL channels for direct C-Plane traffic from the SN to UE 302, the SN transmits a spatial relation indication (SRI) specifying one or more parameter changes to the MN (e.g., via X2 interface). At 1014, the MN then transmits the SRI to the UE via one or more cells of the MCG. At 1016, UE 302 modifies its spatial relation information based on the SRI. At this point, the UE ACKs the SRI via the MN (1018-1020) or via direct transmission to the SN via PUCCH over PSCell (1022). In some designs, for ACKs sent through the PUCCH or MCG, the K1 values may be set to accommodate the long delays of sending PDSCH with spatial relation over MCG or sending the ACK on the PUCCH. In some designs, the SRI is sent to the UE via the MN over RRC signaling, MAC-CE signaling, or DCI signaling.

Table 1 below depicts example SCG message aspects for Scenario 1 and Scenario 2 configurations:

TABLE 1
	Channel	Scenario 1: EN-DC	Scenario 2: NR-DC
Meas. Type	Direction	Inter-band CA	Intra-band CA
RLM and BFD	DL	RLM-RS/BFD-RS on	RLM-RS/BFD-RS on
		PSCELL and SCELLs	PSCELL
		if configured
	UL	Radio Link Failure	Radio Link Failure
		Report/Beam Failure	Report/Beam Failure
		Report via MCG	Report via MCG
		Beam Failure Report	Beam Failure Report via
		via PSCELL (RACH)	PSCELL (RACH)
L1 Measurement,	DL	CSI-RS on PSCELL	CSI-RS on PSCELL
Report and		and SCELLs	Beam updates/timing
Sounding		Beam updates/timing	adjustment
Procedure		adjustment	commands/power control
		commands/power	commands via MCG
		control commands via
		MCG
	UL	Measurement Reports	Measurement Reports
		for PSCELL and	for PSCELL using
		SCELLs using PUCCH	PUCCH on PSCELL
		on PSCELL	SRS on PSCELL
		SRS on PSCELL

Table 2 below depicts example tracking aspects for Scenario 1 configuration:

Scenario 1- EN-DC Inter-band CA
Beam Failure          Beam Failure on PSCELL or SCELLs if
                      configured.
Beam Updates          DL/UL P1 beams on PSCELL and
                      SCELLs (commands maybe delayed)
Timing adjustment and Timing adjustment on PSCELL and
Power control         SCELLs if sharing same TAG ID as
Procedures            PSCELL
                      UL Tx Power control on PSCELL
                      (commands may be delayed)
Table 2

Table 3 below depicts example tracking aspects for Scenario 1 configuration:

TABLE 3
Scenario 2- NR-DC Intra-band CA
Beam Failure          Beam Failure on PSCELL
Beam Updates          DL/UL P1 beams on PSCELL
                      (commands maybe delayed)
Timing adjustment and Timing adjustment and power control on
Power control         PSCELL. (commands may be delayed)
Procedures

In some designs, the BFD report may be relayed via the MCG as noted above. In some designs, RRC signaling may be used to transport the BFD report with an indication of a new beam to apply to the PSCell and/or the SCell(s) of the SCG. However, RRC signaling may be implemented at L3 and may be relatively slow. Hence, in some designs, MAC-CE may be used to transport the BFD report. For example, an additional bit can be added to the MAC-CE to indicate whether an associated BFD report is associated with the MCG or the SCG. In some designs, as shown in FIGS. 9-10, parameter updates (e.g., TCI, SRI, etc.) may be relayed via the MCG. In some designs, the parameter updates may be signaled via RRC (e.g., relatively slowly), while in other designs, the parameter updates may be signaled via MAC-CE and/or DCI (e.g., this approach is faster than RRC, but may require extensive inter-gNB signaling).

Those of skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Further, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

While the foregoing disclosure shows illustrative aspects of the disclosure, it should be noted that various changes and modifications could be made herein without departing from the scope of the disclosure as defined by the appended claims. The functions, steps and/or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although elements of the disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

Claims

1. A method of operating a user equipment (UE), comprising: receiving, while a secondary cell group (SCG) is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications from a secondary node (SN) associated with the SCG over one or more cells of a master cell group (MCG); andtransmitting, while the SCG is associated with the dormant state, uplink C-Plane communications through a primary secondary cell (PSCell) of the SCG to the SN.

2. The method of claim 1, further comprising: performing, while the SCG is associated with the dormant state, one or more measurement-related operations associated with one or more reference signals from one or more cells of the SCG.

3. The method of claim 2, wherein the one or more measurement-related operations comprise: one or more radio resource monitoring (RRM) measurements,one or more radio link monitoring (RLM) measurements,one or more beam failure detection (BFD) measurements,a combination thereof.

4. The method of claim 3, wherein the PSCell of the SCG is associated with a first bandwidth (BW) and one or more secondary cells (SCells) of the SCG are associated with at least a second BW that is different than the first BW, andwherein the one or more measurement-related operations comprise BFD measurements on both the PSCell and the one or more SCells.

5. (canceled)

6. (canceled)

7. The method of claim 2, wherein the one or more measurement-related operations include one or more downlink L1 measurements of one or more L1 reference signals and/or transmission of one or more L1 sounding reference signals (SRSs).

8. The method of claim 7, wherein the one or more L1 reference signals comprise: one or more periodic, semi-periodic or aperiodic channel state information reference signals (CSI-RSs),one or more beam failure detection reference signals (BFD-RS),one or more aperiodic tracking reference signals (TRSs), ora combination thereof.

9. The method of claim 7, wherein the one or more L1 SRSs comprise periodic, semi-periodic or aperiodic SRSs.

10. The method of claim 7, wherein the one or more L1 SRSs are multiplexed with a physical uplink control channel (PUCCH) communication.

11. The method of claim 7, further comprising: transmitting a measurement report based on the one or more downlink L1 measurements to the SN.

12. The method of claim 7, wherein the one or more L1 downlink reference signals are received from the SN.

13. The method of claim 1, wherein the downlink C-Plane communications received over the MCG comprise control information related to one or more of a beam update, a timing adjustment and/or a power control command associated with one or more cells of the SCG.

14. The method of claim 1, wherein the PSCell of the SCG is associated with a first bandwidth (BW) and one or more secondary cells (SCells) of the SCG are associated with at least a second BW that is different than the first BW.

15. The method of claim 14, wherein the one or more cells of the MCG are associated with the first BW, orwherein the one or more cells of the MCG are associated with a third BW that is different than the first or second BWs.

16. The method of claim 1, further comprising: performing, while the SCG is associated with the dormant state, L3 measurements on one or more cells of the SCG; andtransmitting an L3 measurement report based on the L3 measurements to the MCG.

17. A method of operating a base station configured as a master node (MN) of a master cell group (MCG) for a user equipment (UE), comprising: receiving, from a secondary node (SN) of a secondary cell group (SCG) of the UE while the SCG of the UE is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE; andtransmitting the downlink C-Plane communications to the UE.

18. (canceled)

19. The method of claim 17, wherein the downlink C-Plane communications transmitted over the MCG comprise control information related to one or more of a beam update, a timing adjustment and/or a power control command associated with one or more cells of the SCG.

20. The method of claim 17, further comprising: receiving, from the UE, an L3 measurement report based on L3 measurements on one or more cells of the SCG.

21. A method of operating a base station configured as a secondary node (SN) of a secondary cell group (SCG) for a user equipment (UE), comprising: transmitting, to a master node (MN) of a master cell group (MCG) of the UE while the SCG is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE; andreceiving, over a primary secondary cell (PSCell) of the SCG while the SCG is associated with the dormant state, uplink C-Plane communications from the UE.

22. The method of claim 21, further comprising: transmitting, while the SCG is associated with the dormant state, one or more reference signals from one or more cells of the SCG.

23. (canceled)

24. (canceled)

25. The method of claim 22, wherein the one or more reference signals comprise one or more downlink L1 reference signals.

26. The method of claim 25, further comprising: receiving, from the UE, a measurement report including one or more downlink L1 measurements of the one or more downlink L1 reference signals.

27. The method of claim 25, wherein the one or more L1 reference signals comprise: one or more periodic, semi-periodic or aperiodic channel state information reference signals (CSI-RSs),one or more beam failure detection reference signals (BFD-RS),one or more aperiodic tracking reference signals (TRSs), ora combination thereof.

28. The method of claim 21, further comprising: receiving, from the UE while the SCG is associated with the dormant state, one or more L1 sounding reference signals (SRSs).

29. The method of claim 28, wherein the one or more L1 SRSs comprise periodic, semi-periodic or aperiodic SRSs.

30. The method of claim 28, wherein the SRS is multiplexed with a physical uplink control channel (PUCCH) communication.

31. The method of claim 21, wherein the downlink C-Plane communications transmitted to the MCG comprise control information related to one or more of a beam update, a timing adjustment and/or a power control command associated with one or more cells of the SCG.

32. The method of claim 21, wherein the PSCell of the SCG is associated with a first bandwidth part (BW) and one or more secondary cells (SCells) of the SCG are associated with at least a second BW that is different than the first BW.

33. The method of claim 32, wherein the one or more cells of the MCG are associated with the first BW, orwherein the one or more cells of the MCG are associated with a third BW that is different than the first or second BWs.

34. A user equipment (UE), comprising: a memory;at least one transceiver; andat least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: receive, while a secondary cell group (SCG) is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications from a secondary node (SN) associated with the SCG over one or more cells of a master cell group (MCG); andtransmit, while the SCG is associated with the dormant state, uplink C-Plane communications through a primary secondary cell (PSCell) of the SCG to the SN.

35. A base station configured as a master node (MN) of a master cell group (MCG) for a user equipment (UE), comprising: a memory;at least one transceiver; andat least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor configured to: receive, from a secondary node (SN) of a secondary cell group (SCG) of the UE while the SCG of the UE is associated with a dormant state with downlink and uplink user plane (U-Plane) communications over SCG disabled, downlink control plane (C-Plane) communications associated with the SCG for transmission to the UE; andtransmit the downlink C-Plane communications to the UE.