Patent Application
20240357443
The present disclosure generally relates to wireless communications and more specifically relates to suspending a switching process for a time interval following a handover of a user equipment (UE) between base stations (e.g., Next Generation NodeBs (gNBs)) of a wireless network (e.g., a fifth generation (5G) (e.g., New Radio (NR)) network).
As employed on a mobile telephony device (e.g., mobile phone, satellite phone, smart watch, computer, camera, and so on), a Subscriber Identity Module (SIM) card is an integrated circuit running a Card Operating System (COS) that is intended to securely store the International Mobile Subscriber Identity (IMSI) number and its related encryption key for the device. This number and key are used to identify and authenticate the associated subscriber of a mobile communication network supporting the device.
A Universal Subscriber Identity Module (USIM) is the functional equivalent of a SIM in that it stores subscriber-related information. Additionally, a USIM operates as a miniature computer that may handle several miniature applications, such as the implementation of enhanced security functions pertaining to authentication and ciphering on the user side in mobile telephony devices.
In some cases, a mobile telephony device, which may be more generally referred to as a user equipment (UE), may be a multiple-USIM (Multi-USIM or MUSIM) device. In the consumer market, some commercially deployed UEs support a configuration with more than one USIM (e.g., typically two USIMs), each of which may be associated with the same or a different network. Support for a MUSIM device is conventionally handled in an implementation-specific manner without any support from 3rd Generation Partnership Project (3GPP) specifications, resulting in a variety of implementations. An implementation-specific MUSIM device typically uses common radio and baseband components that are shared among the multiple USIMs and under the control of a single processor, which may lead to issues that negatively impact 3GPP system performance.
For example, while actively communicating with a first network associated with a first USIM (USIM-A), the UE may occasionally check a second network associated with a second USIM (USIM-B) (e.g., to monitor the paging channel, detect a Synchronization Signal Block (SSB), perform signal measurements, or read system information) and decide, for example, if the UE should respond to a paging request from the other system. This occasional activity on the second network may or may not have any performance impact, depending on the UE implementation.
Paging Occasions (POs) are typically calculated based on the UE identifier (e.g., IMSI and 5G Serving Temporary Mobile Subscriber Identity (5G-S-TMSI) for Evolved Packet System (EPS) and 5G System (5GS), respectively). In some cases, the UE identifier values associated with the different USIMs may lead to systematic collisions that may result in missed pages (e.g., a page on the first network associated with USIM-A occurs at, or nearly at, the same time as a page on the second network associated with USIM-B).
Further, when the UE receives a page on the second network, the UE may be configured to decide whether to respond to the page (e.g., by following user-configured rules). In the absence of information indicating the service type that has triggered the paging (e.g., voice or data service), the UE may have to blindly decide whether to ignore or respond to the page.
Thereafter, in cases in which the UE decides to respond to the page in the second network, or when the UE is required to perform some signaling activity (e.g., Periodic Mobility Registration Update) in the second network, the UE may be required to stop its current activity in the first network. In the absence of any procedure for suspension of the ongoing activity, the UE may autonomously release the Radio Resource Control (RRC) connection with the first network and abruptly leave the network. Such release is likely to be interpreted by the first network as an error case, which may distort connection statistics in the first network and thus misguide algorithms that rely on the statistics. Moreover, during the UE's absence, the first network may keep paging the UE, which may result in wasting paging resources.
Currently, the 3GPP is addressing the functionality of a Multi-USIM device as the functionality pertains to the coordinated operation of the device in and with a 3GPP network. As such functionality may impact the physical layer, radio protocol, and radio architecture enhancements, as well as Service and System Aspects (SAs), the issue is being addressed in the 3GPP Technical Specification Group (TSG) SA Working Group 1 (WG1) (referred to as SA1), 3GPP TSG SA WG2 (SA2), and 3GPP TSG RAN WG2 (RAN2) working groups.
As a result of this work, in some proposals, a UE may be configured to switch its communication resources from a first network to a second network (referred to as “network switching” or more simply “switching”) to facilitate MUSIM functionality. When switching from a first network to a second network, the UE may tune its receiver/transmitter away from the time and frequency resources associated with the first network to the time and frequency resources associated with the second network. Switching functionality may be enabled by a configuration of the UE, where the UE may access the time and frequency resources of the first network as associated with a first USIM and the time and frequency resources of the second network as associated with a second USIM of the UE in a time-division-multiplexed (TDM) manner.
Currently, two kinds of switching procedures have been proposed. According to the first procedure, the UE may tune away from a gNB of the first network to a gNB of the second network for short periods of time. Such periods are known by the UE and by the gNB of the first network to be sufficiently short such that the UE may tune, receive, and decode paging occasions and other network type information from the gNB of the second network and then retune back to the gNB of the first network within such a period of time that the gNB of the first network does not experience Radio Link Failure (RLF) and/or Beam Failure Detection (BFD) with the UE. The network type information may include, for example, System Information (SI) receiving, Synchronization Signal Block (SSB) detection, serving cell and neighboring cell signal measurement (e.g.,intra-frequency, inter-frequency, and inter-radio-access-technology (inter-RAT) measurement). Such switching is referred to as “Switching Without Leaving RRC_CONNECTED”, or simply “Switching Without Leaving”.
According to the second switching procedure, the UE may tune away from the gNB of the first network to use time and frequency resources of the gNB of the second network for periods of time that are sufficiently long and continuous in duration that the UE cannot maintain a connection to the gNB of the first network without the gNB of the first network experiencing RLF and/or BFD. Thus, the UE must leave the RRC_CONNECTED state associated with the gNB of the first network before switching to the gNB of the second network. Such switching is known as “Switching with Leaving RRC_CONNECTED”, or simply “Switching with Leaving”.
For the case of Switching Without Leaving, the UE may know the duration and periodicity of paging occasions and other network type information events that occur with the gNB of the second network. Thus, to assist the UE in receiving the periodic network type information from the gNB of the second network, the UE may request the gNB of the first network to not schedule any uplink (UL) or downlink (DL) time and frequency resources during one or more periods of time when the UE intends to receive/transmit information on the gNB of the second network. The term “gap” is used to define such a period of time when the gNB of the first network does not schedule any UL or DL time and frequency resources for the UE. Accordingly, the aforementioned period of time allows the UE to omit interactions (e.g., receiving/transmitting data) with the gNB of the first network. The gap may delimit a period of time during which the UE may be busy receiving and/or transmitting data from/to a gNB of another cell and/or network. For the purposes of this disclosure, a gap in the UL or DL time and frequency resources of a gNB of a first network may be scheduled to provide the UE with the opportunity to switch from the gNB of the first network to a gNB of the second network for a scheduled period of time that aligns with transmissions of network information of the second network. In some examples, a gap may be scheduled by a gNB of a network to reoccur at a fixed periodicity.
As proposed in greater detail below, a gap schedule between the UE and the gNB of the first network may be subsequently employed between the UE and a second gNB of the first network during and/or after a handover of the UE from the first gNB to the second gNB, thus possibly facilitating an efficient use of time and frequency resources at least through the handover process. However, employing the gap schedule immediately after completion of the handover process may interfere with the transfer of data between the second gNB of the first network and the UE that was not previously transported, and thus is buffered or queued at the network or the UE, during the execution of the handover. This interference may significantly exacerbate data transfer latency that typically results from a handover process while attempting to efficiently employ the use of Switching Without Leaving after the handover.
In one example, a user equipment (UE), comprising: one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and at least one processor coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to: while maintaining a first Radio Resource Control (RRC) connection with a first base station (BS) of a first network, receive transmissions from a BS of a second network during at least one time period specified in a switch gap configuration; receive an RRC reconfiguration message from the first BS of the first network, the RRC reconfiguration message comprising a first command and a second command, the first command instructing the UE to begin a handover procedure from the first BS of the first network to a second BS of the first network, and the second command controlling usage of the switch gap configuration by the UE following completion of the handover procedure; initiate execution of the handover procedure according to the first command; and when the second command suspends continued usage of the switch gap configuration during a time interval following the completion of the handover procedure, suspend reception of transmissions from the BS of the second network during the time interval.
In one example, a base station (BS) of a first network, the BS comprising: one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and at least one processor coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to: maintain a first Radio Resource Control (RRC) connection with a user equipment (UE) while facilitating gaps in communication with the UE according to a switch gap configuration; and transmit, to the UE, an RRC reconfiguration message comprising a first command and a second command, the first command instructing the UE to begin a handover procedure from the BS of the first network to another BS of the first network, and the second command controlling usage of the switch gap configuration by the UE following completion of the handover procedure.
In one example, a base station (BS) of a first network, the BS comprising: one or more non-transitory computer-readable media having computer-executable instructions embodied thereon; and at least one processor coupled to the one or more non-transitory computer-readable media and configured to execute the computer-executable instructions to: receive, from another BS of the first network, a handover request message for a user equipment (UE), the handover request message comprising a switch gap configuration that specifies at least one time period during which the UE receives transmissions from a BS of a second network; generate an RRC reconfiguration message comprising a first command and a second command, the first command instructing the UE to begin a handover procedure from the other BS of the first network to the BS of the first network, and the second command controlling usage of the switch gap configuration by the UE following completion of the handover procedure; and transmit, to the other BS, a handover request acknowledgment message comprising the RRC reconfiguration message.
Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.
The 3GPP is a collaboration agreement that aims to define globally applicable technical specifications and technical reports for third and fourth generation wireless communication systems. The 3GPP may also define specifications for next generation mobile networks, systems, and devices.
3GPP Long Term Evolution (LTE) is the name given to a project to improve the Universal Mobile Telecommunications System (UMTS) mobile phone or device standard to cope with future requirements. In one aspect, UMTS has been modified to provide support and specification for the Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN).
At least some aspects of the systems and methods disclosed herein may be described in relation to the 3GPP LTE, LTE-Advanced (LTE-A) and other standards (e.g., 3GPP Releases 8, 9, 10, 11, 12, 13, 14, 15, and so on) including New Radio (NR) which is also known as 5G. However, the scope of the present disclosure should not be limited in this regard. At least some aspects of the systems and methods disclosed herein may be utilized in other types of wireless communication systems.
A wireless communication device may be an electronic device used to communicate voice and/or data to a base station (BS), which in turn may communicate with a network of devices (e.g., public switched telephone network (PSTN), the Internet, etc.). In describing systems and methods herein, a wireless communication device may alternatively be referred to as a mobile station, a UE, an access terminal, a subscriber station, a mobile terminal, a remote station, a user terminal, a terminal, a subscriber unit, a mobile device, etc. Examples of wireless communication devices may include cellular phones, smart phones, personal digital assistants (PDAs), laptop computers, netbooks, e-readers, wireless modems, etc.
In the 3GPP specifications, a wireless communication device may typically be referred to as a UE. However, as the scope of the present disclosure should not be limited to the 3GPP standards, the terms “UE” and “wireless communication device” may be used interchangeably herein to mean the more general term “wireless communication device.” A UE may also be more generally referred to as a terminal device.
In the 3GPP specifications, a BS is typically referred to as a NodeB, an evolved NodeB (eNB), a home enhanced or evolved NodeB (HeNB), a Next Generation NodeB (gNB) or some other similar terminology. As the scope of the disclosure should not be limited to 3GPP standards, the terms “base station,” “NodeB,” “eNB,” “HeNB,” and “gNB” may be used interchangeably herein to mean the more general term “base station.” Furthermore, the term “base station” or “BS” may be used to denote an access point. An access point may be an electronic device that provides access to a network (e.g., Local Area Network (LAN), the Internet, etc.) for wireless communication devices. The term “communication device” may be used to denote both a wireless communication device and/or a base station. An eNB and/or gNB may also be more generally referred to as a base station device.
It should be noted that as used herein, a “cell” may be any communication channel that is specified by standardization or regulatory bodies to be used for International Mobile Telecommunications-Advanced (IMT-Advanced) and all of it or a subset of it may be adopted by 3GPP as licensed bands (e.g., frequency bands) to be used for communication between an eNB and a UE. It should also be noted that in the E-UTRA and E-UTRAN overall description, as used herein, a “cell” may be defined as a “combination of downlink and optionally uplink resources.” The linking between the carrier frequency of the downlink resources and the carrier frequency of the uplink resources may be indicated in the system information transmitted on the downlink resources.
“Configured cells” are those cells of which the UE is aware and is allowed by an eNB and/or gNB to transmit or receive information. “Configured cell(s)” may be serving cell(s). The UE may receive system information and perform the required measurements on all configured cells. “Configured cell(s)” for a radio connection may include a primary cell and/or no, one, or more secondary cell(s).
“Activated cells” are those configured cells on which the UE is transmitting and receiving. That is, activated cells are those cells for which the UE monitors the physical downlink control channel (PDCCH) and, in the case of a downlink transmission, those cells for which the UE decodes a physical downlink shared channel (PDSCH). “Deactivated cells” are those configured cells for which the UE is not monitoring the transmission of PDCCH. It should be noted that a “cell” may be described in terms of differing dimensions. For example, a “cell” may have temporal, spatial (e.g., geographical), and frequency characteristics.
The 5G communication systems, dubbed NR technologies by the 3GPP, envision the use of time/frequency/space resources to allow for services, such as Enhanced Mobile Broadband (eMBB) transmission, Ultra-Reliable Low-Latency Communications (URLLC) transmission, and massive Machine Type Communication (mMTC) transmission. Also, in NR, single-beam and/or multi-beam operations are considered for downlink and/or uplink transmissions.
Various examples of the systems and methods disclosed herein are now described with reference to the figures, where like reference numbers may indicate functionally similar elements. The systems and methods as generally described and illustrated in the Figures herein could be arranged and designed in a wide variety of different implementations. Therefore, the detailed description of the present disclosure as illustrated in the figures is not intended to limit scope of the present disclosure but is merely representative of the systems and methods.
According to various implementations of the present disclosure, a mechanism is discussed by which a “gap configuration” (or, as also used below, a “switch gap configuration”) specifying one or more gaps scheduled between a UE and a first gNB of a first network, as described above, may be transported from the first gNB to a second gNB of the first network as part of a handover operation. More specifically, a switch gap configuration may include data specifying one or more time periods, or “gaps”, when the gNB of the first network does not schedule any UL or DL time and frequency resources for the UE. Accordingly, the aforementioned periods of time may allow the UE to omit interactions (e.g., receiving and/or transmitting of data) with the gNB of the first network (e.g., such that the UE may employ those time periods to “switch” to a gNB of a second network to receive paging and other information). Such implementations may thus facilitate use of the gaps by the UE during and/or after the handover operation, thus retaining the efficiency associated with the Switching Without Leaving procedure during that time.
However, under some circumstances, allowing such switching after the completion of a handover operation may negatively impact data transfer latency in the short term. For example, a significant amount of data may have been buffered by the UE and/or the first gNB of the first network during the handover operation (e.g., while the UE was not connected to either the first gNB or the second gNB). Consequently, in some implementations described below, to facilitate an efficient transfer of data after completion of the handover operation, switching operations may be suspended for some period of time to increase the number of UL or DL frequency and time resources provided by the second gNB immediately after completion of the handover operation.
The term “handover” may herein refer to a procedure performed jointly by a UE and a wireless network to switch/change at least one serving cell serving the UE to another cell during a connected state (e.g., RRC_CONNECTED state). The at least one serving cell may include, but is not limited to, a primary cell (PCell), a secondary cell (SCell), a primary secondary cell (PSCell), or a combination thereof. Such a serving cell may be a part/member of a master cell group (MCG) or a secondary cell group (SCG).
In further reference to
To facilitate discussion in portions of the description below, first gNB-1 of first network NW-1 (as shown in
In some implementations, the UE may accomplish a request for one or more gaps by sending gNB-1_NW-1 a Gap Configuration Assistance Information Message via an IE (e.g., a new IE called switchGapConfig). The transport of the switchGapConfig IE to gNB-1_NW-1 may be provided by UL-DCCH-Message::UEAssistanceInformation. In some implementations, the format of switchGapConfig may be derived from an existing IE (e.g., the measGapConfig IE, as described in Technical Specification (TS) 38.331), such as by employing various parameters sufficient to identify and request one or more time intervals or periods during which UL and DL time and frequency resources for the UE are not to be scheduled by a gNB (e.g., gNB-1_NW-1, for the purpose of paging, receiving system information, and so on with gNB-n_NW-2).
In some implementations, the gaps requested in a Gap Configuration Assistance Information Message may be any of three types: “Periodic Gap”, “A-periodic Gap”, and “Autonomous Gap”. A Periodic Gap may provide for a repeating period of time (e.g., establishing a pattern) where a gNB does not schedule any UL or DL time and frequency resources for the UE. An A-periodic Gap may provide for a single period of time where a gNB does not schedule any UL or DL time and frequency resources for the UE. An Autonomous Gap may indicate that the network does not configure gaps for the UE. The Gap Configuration Assistance Information Message may include multiple gap requests (e.g., two different Periodic gap patterns, or one Periodic gap pattern and one a-periodic gap, or other combinations).
In some implementations, the information provided by the UE to a gNB of first network NW-1 about a switching gap configuration via the Gap Configuration Assistance Information Message may include information about the starting time of the gap (e.g., expressed as an offset value or start System Frame Number (SFN), and a subframe), the gap length, and the gap repetition period. However, as the timing of the transmission of network resources between different networks may not be the same, the UE may map the timing information of the gap relative to a gNB of second network NW-2 (e.g., gNB-n_NW-2) onto the timing of the gNB of first network NW-1 (e.g., gNB-1_NW-1). Accordingly, the request to gNB-1_NW-1 may be in the form of mapped timing values of gNB-n_NW-2.
As a result of the Gap Configuration Assistance Information Message provided by the UE to gNB-1_NW-1, in some implementations, gNB-1_NW-1 may in turn provide the UE with a Gap Configuration Assistance Information Response Message (e.g., via the switchGapConfig IE, as described above). The switchGapConfig IE may include one or more switch gap configurations for the switching process. The transport of the switchGapConfig IE to the UE may be provided by DL-DCCH::RRCReconfiguration.OtherConfig. The one or more switch gap configurations provided in a Gap Configuration Assistance Information Response Message may include any of the three types discussed above: Periodic Gap, A-periodic Gap, and/or Autonomous Gap. The Gap Configuration Assistance Information Response Message may include one or more gap results. For example, the one or more switch gap configurations may define one or more gaps (e.g., periodic, a-periodic, and/or autonomous gaps) where gNB-1_NW-1 will not assign the UE any UL/DL time and frequency resources, and thus the UE may tune away from gNB-1_NW-1 during those gaps to receive information from gNB-n_NW-2 and not miss receiving DL data or miss transmitting UL data with gNB-1_NW-1. In some implementations, the gaps may be synchronized to the NR/LTE frame structure.
As a result, if the UE is actively Switching Without Leaving gNB-1_NW-1 to receive paging and other signaling on gNB-n_NW-2, then the gaps in the gNB-1_NW-1 gap schedule of transmission/reception resources may enable the UE to switch to gNB-n_NW-2 without missing scheduled transmission/reception resources of gNB-1_NW-1. The gap schedules may be based upon the one or more switch gap configurations that were previously agreed to by both the UE and gNB-1_NW-1.
In some situations, however, if the UE is handed over from gNB-1_NW-1 to a second gNB of first network NW-1 (e.g., gNB-2_NW-1) and the UE is actively Switching Without Leaving gNB-1_NW-1 to receive paging and other system information via gNB-n_NW-2, then upon reception of a command by the UE to engage in a handover operation (e.g., via a RRCReconfiguration message) from gNB-1_NW-1 to gNB-2_NW-1, the UE may be compelled to terminate the switching procedure between gNB-1_NW-1 and gNB-n_NW-2, as gNB-2_NW-1 does not possess a copy of the previously generated one or more switch gap configurations that could otherwise be used by gNB-2_NW-1 to create gaps in the transmission and/or reception resources scheduled for the UE by gNB-2_NW-1 during or following the handover. For example, such gaps may be employed to provide the UE with opportunities to Switch Without Leaving gNB-2_NW-1 to receive paging and other information via gNB-n_NW-2.
In some cases, the termination of the switching procedure by a concurrent handover process may cause the UE to miss pages on gNB-n_NW-2 until the UE can restart the switching procedure between the UE and gNB-2_NW-1 following the successful completion of the handover process. In addition, to restart the switching procedure between the UE and gNB-2_NW-1 after the handover, the UE may acquire one or more new switch gap configurations from gNB-2_NW-1, which may force the UE to send a Gap Configuration Assistance Information Message representing the timing of periodic and aperiodic network type information of gNB-n_NW-2 to gNB-2_NW-1 such that gNB-2_NW-1 may reply to the UE with the one or more new switch gap configurations. However, such a request by the UE to gNB-2_NW-1 subsequent to the handover may represent a waste of resources, as the one or more switch gap configurations received from gNB-2_NW-1 subsequent to the handover may be the same as those received by the UE from gNB-1_NW-1 prior to the handover from gNB-1_NW-1, because the one or more switch gap configurations from gNB-1_NW-1 and from gNB-2_NW-1 may be based on the same timing of periodic and aperiodic network type information of gNB-n_NW-2. Consequently, various implementations of the present disclosure may facilitate the sharing of the previously generated switch gap configuration information with gNB-2_NW-1.
Additionally, as mentioned above, the handover process may cause both the UE and the network to experience a first time period during which DL data from the network and UL data from the UE cannot be transported. In some examples, the first time period may begin with the termination of the connection of the UE to the source gNB (gNB-1_NW-1) and ending with the reconnection of the UE to the target gNB (gNB-2_NW-1). UL data that is not transported by the UE during this first time period of the handover process may be queued at the UE until a connection between the UE and gNB-2_NW-1 is established, and resources are made available for transport. Additionally, DL data that is not transported by gNB-1_NW-1 during this first time period of the handover process may be queued at gNB-1_NW-1 and subsequently forwarded during the handover process to gNB-2_NW-1, for example, via the Xn/NG network connection for transport to the UE after a connection between the UE and gNB-2_NW-1 is established, and resources are made available for transport.
Consequently, immediately following completion of the handover process of the UE from gNB-1_NW-1 to gNB-2_NW-1 and a connection between the UE and gNB-2_NW-1 is established, and resources are made available for transport of data between the UE and gNB-2_NW-1, a second time period may be identified during which the data queued for transport (at the UE and gNB-2_NW-1) and the switching gaps (e.g., preconfigured by gNB-2_NW-1 for the UE) may overlap in time with respect to the same Tx/Rx resources of gNB-2_NW-1. As a consequence of this overlap, resources that could be used for the transport of queued data are instead reserved as switching gaps for the UE. Thus, the overlap may lead to inefficient allocation of resources by gNB-2_NW-1 and undesirable switching behavior by the UE if no action is taken by gNB-2_NW-1 to modify the pre-agreed behavior of the UE that allows the UE to switch to gNB-n_NW-2 during gap periods that may occur during this second time period.
An example of a scenario leading to such inefficient resource allocation by gNB-2_NW-1 and undesirable behavior by the UE may occur if the data queued for transport during the handover process has a higher priority than the switching gaps. In such a scenario, the higher priority queued data should be transported immediately during the second time period using all available resources. Accordingly, if gNB-2_NW-1 does not coordinate with the UE prior to the second time period to prevent the continued usage of pre-agreed switching gaps by the UE during the second time period, gNB-2_NW-1 may be forced to continue a reserve allocation of Tx/Rx resources for lower priority switching gaps while allocating the remaining Tx/Rx resources to clear the higher priority data queues.
For the remainder of this disclosure, the terms “suspension interval”, “time interval”, and/or “interval” may refer to a period of time following the completion of a handover process of a UE from a source gNB (e.g., gNB-1_NW-1) to a target gNB (e.g., gNB-2_NW-1). In some implementations, the interval may start with the establishment of a connection between the UE and the target gNB such that resources are made available for the transport of data between the UE and the target gNB, and the interval may end when the data queued at the UE and the target gNB are cleared or estimated to be cleared. During that interval, the scheduling of Tx/Rx resources by the target gNB for the UE that could be used for the transport data queued at the UE and target gNB may overlap the resources reserved for switching gaps (e.g., preconfigured by the target gNB for the UE).
Also, for the remainder of this disclosure, while the abbreviation “gNB” is employed to identify the 5G NodeB base station, this reference may also apply to a Next Generation Evolved Node-B (eNB) base station. Also, within this disclosure, the terms “terminal”, “device”, “User Equipment”, and “UE” may be used interchangeably.
Additionally, for the remainder of this disclosure, a Multi-USIM (MUSIM) device may be presumed to be configured with a USIM-A associated with first network NW-1 (or NW-A) and a USIM-B associated with second network NW-2 (or NW-B), as illustrated in
For example, a switching procedure may be provided to enable the UE to switch between (1) the use of UL/DL time and frequency resources as scheduled by a gNB of first network NW-1 (e.g., gNB-1_NW-1) that is associated with a first USIM (USIM-A) of the UE and (2) the use of UL/DL time and frequency resources as scheduled by a gNB of second network NW-2 (e.g., gNB-n_NW-2) that is associated with a second USIM (USIM-B) of the UE while not disregarding or “missing” any time and frequency resources scheduled to the UE by gNB-1_NW-1.
In some implementations, the switching procedure may include a method for the acquisition of configuration data from gNB-1_NW-1 by way of the UE requesting such data (e.g., by sending a Gap Configuration Assistance Information message to gNB-1_NW-1), where the configuration data may be employed to control the operation of the switching procedure. The configuration data may include one or more switch gap configurations. In some implementations, the one or more switch gap configurations may identify periods of time where gNB-1_NW-1 will not schedule UL or DL time and frequency resources for the UE. Such periods of time may be used by the switching procedure to determine opportunities when the UE can network-switch from gNB-1_NW-1 to gNB-n_NW-2 for the purpose of using time and frequency resources of gNB-n_NW-2 while not missing any scheduled time and frequency resources of gNB-1_NW-1. The duration and periodicity of the timing periods of the one or more switch gap configurations, having been proposed by the UE to the gNB-1_NW-1, for example, via the Gap Configuration Assistance Information message, may be either accepted or rejected by gNB-1_NW-1.
In some implementations, as indicated in
Accordingly, in some implementations, the UE may create at least one Gap Configuration Assistance Information Message that identifies the timing periods when the UE may desire to receive pages, SIB update information, and/or other broadcast information from gNB-n_NW-2. Further, in some implementations, the UE may transmit the Gap Configuration Assistance Information Message to gNB-1_NW-1 at operation 208 via UL-DCCH-Message.UEAssistanceInformation.switchGapConfig. The gNB-1_NW-1 may respond to the Gap Configuration Assistance Information Message by transmitting to the UE at least one switch gap configuration message, for example, in a Configuration Assistance Information Response message at operation 210 (e.g., via DL-DCCH::RRCReconfiguration.OtherConfig.switchGapConfig).
In some implementations, the switching procedure may begin using the one or more switch gap configurations to determine opportunities when the UE can Switch Without Leaving gNB-1_NW-1 to receive paging and other information from gNB-n_NW-2 at operation 212. The switching procedure may be enabled to use the one or more switch gap configurations upon receipt of the RRCReconfiguration.OtherConfig message that transported the switchGapConfig IE.
The switch gap configurations that are actively in use by the switching procedure to determine opportunities when the UE can Switch Without Leaving a first network to a second network (e.g., first network NW-1 to second network NW-2) may be referred to as the “currently-jointly-in-use” one or more switch gap configurations, which indicates that a gNB is actively using the one or more switch gap configurations to create gaps in the UL/DL time and frequency resources scheduled to a UE, and the switching procedure is actively using the same one or more switch gap configurations to determine opportunities when the UE can Switch Without Leaving first network NW-1 to second network NW-1.
In various implementations described herein, as depicted in diagram portions 200A and 300A of
In an example operation, gNB-1_NW-1 may provide to gNB-2_NW-1 a copy of the currently-jointly-in-use one or more switch gap configurations being used by the UE. In some implementations, gNB-1_NW-1 may provide the copy to gNB-2_NW-1 following a determination by gNB-1_NW-1 to hand over the UE to gNB-2_NW-1, but before gNB-1_NW-1 issues a handover command to the UE. In some implementations, gNB-1_NW-1 may render the handover decision (HO Decision at operation 222 in
In some implementations, a benefit of providing gNB-2_NW-1 a copy of the currently-jointly-in-use one or more switch gap configurations prior to the handover is that the UE then may not have to reacquire one or more switch gap configurations from gNB-2_NW-1 via a Gap Configuration Assistance Information message sent by the UE to gNB-2_NW-1 following the handover, thus conserving time and frequency resources.
In some implementations, gNB-1_NW-1 and gNB-2_NW-1 may communicate via the Xn/NG interface to transport configuration and control data. Further, in some implementations, the transport of configuration data and control data from gNB-1_NW-1 to gNB-2_NW-1 via the Xn/NG interface in preparation for (e.g., prior to) a handover may utilize a handover request message at operation 224 (e.g., more specifically, the HANDOVER-REQUEST Message of TS 36.413). More particularly, the HANDOVER-REQUEST Message may be used for the passing of the Source-To-Target-Transparent-Container (e.g., see TS 29.280), which may be used for passing an RRC-Container, which may contain information necessary for preparing gNB-2_NW-1 to accept the handover. The Source-To-Target-Transparent-Container included in the handover request message may contain one or more switch gap configurations, possibly along with other configuration and control data. Via this mechanism, gNB-1_NW-1 may send the copy of the currently-jointly-in-use one or more switch gap configurations to indicate to gNB-2_NW-1 that gNB-1_NW-1 is providing gaps in the schedule of UL or DL time and frequency resources for the UE as defined by the one or more switch gap configurations.
In some implementations, the Source-To-Target-Transparent-Container included in the handover request message may further include information that gNB-2_NW-1 may employ to determine whether the use of gap switching, as described above, should be paused or suspended for some suspension interval after completion of the handover command. In some implementations, this information may include, but not limited to, one or more of a value indicating the UL/DL data throughput (e.g., average, maximum, or the like) between the UE and gNB-1_NW-1, a value indicating an amount of DL data intended for the UE that is buffered (e.g., currently buffered) at gNB-1_NW-1, and/or a value indicating an amount of UL data intended for gNB-1_NW-1 that is buffered (e.g., currently buffered) at the UE. Other information to facilitate a decision by gNB-2_NW-1 as to whether use of the switch gap configurations may be employed may also be included in conjunction with the handover request in other implementations.
In another example operation, the method may include gNB-2_NW-1 receiving, from gNB-1_NW-1, a copy of the currently-jointly-in-use at least one switch gap configurations, as well as the additional information described above, prior to the handover of the UE from gNB-1_NW-1 to gNB-2_NW-1. As indicated above, in some implementations, gNB-1_NW-1 and gNB-2_NW-1 may communicate via the Xn/NG interface to transport configuration and control data. Further, in some implementations, the transport of configuration data and control data from gNB-1_NW-1 to gNB-2_NW-1 via the Xn/NG interface in preparation for (e.g., prior to) a handover may use a handover request message (e.g., the HANDOVER-REQUEST Message of TS38.423). In some implementations, the HANDOVER-REQUEST Message may be used for the passing of the Source-To-Target-Transparent-Container (e.g., sec TS 29.280), which may be used for passing an RRC-Container, which may contain in-formation necessary for preparing gNB-2_NW-1 to accept the handover. The Source-To-Target-Transparent-Container included in the handover request message may contain one or more switch gap configurations, possibly in addition to other configuration and control data (e.g., the throughput and buffered data amount values described above). Accordingly, reception by gNB-2_NW-1 of the copy of the currently-jointly-in-use one or more switch gap configurations indicates to gNB-2_NW-1 that gNB-1_NW-1 is currently providing gaps in its schedule of UL or DL time and frequency resources for the UE, as defined by the one or more switch gap configurations.
In some implementations, in response to receiving the handover request, gNB-2_NW-1 may perform admission control at operation 226 to reserve resources to facilitate communication with the UE. In some implementations, the admission control may take into account the one or more switch gap configurations received such that the UE may switch from gNB-2_NW-1 to gNB-n_NW-2 while remaining connected to gNB-2_NW-1 during and/or after the handover operation.
Additionally, at operation 228, gNB-2_NW-1 may evaluate information regarding data throughput and/or buffered data amounts received in conjunction with the handover request to determine whether a suspension interval should be imposed on the UE to facilitate the efficient, prioritized transfer of buffer data that has accumulated at the UE and/or gNB-1_NW-1 during the handover. In some implementations, gNB-2_NW-1 may evaluate one or more of the values indicating the UL/DL data throughput between the UE and gNB-1_NW-1, the value indicating the amount of DL data buffered at gNB-1_NW-1, and the value indicating the amount of UL data buffered at the UE among other values/criteria.
In some implementations, this evaluation may result in an estimation of the amount of data that will be queued at the UE and at gNB-1_NW-1 that may be forwarded to gNB-2_NW-1 upon a successful completion of the handover procedure by the UE from gNB-1_NW-1 to gNB-2_NW-1.
In some implementations, the evaluation may result in an estimation of the amount of UL/DL resources needed to clear the data estimated to be queued or buffered at the UE and at gNB-2_NW-1, where the data estimated to be queued at gNB-2_NW-1 may include an amount of data that may be forwarded from gNB-1_NW-1 and an estimated amount of data to be received directly from the gateway of NW-1 following the successful completion of the handover procedure by the UE from gNB-1_NW-1 to gNB-2_NW-1.
In some implementations, the evaluation may result in an estimated time period that may be required to transport the data estimated to be queued at UE, the data estimated to be queued at gNB-2_NW-1, and the data to be forwarded to gNB-2_NW-1 based on the estimated UL/DL resources needed to clear all of the data estimated to be queued at the UE, data estimated to be queued at gNB-2_NW-1, and data to be forwarded to gNB-2_NW-1 following the successful completion by the UE of the handover procedure from gNB-1_NW-1 to gNB-2_NW-1.
Further, in some implementations, gNB-2_NW-1 may compare the estimated time period to a threshold. Additionally, gNB-2_NW-1 may compare the priority of transporting queued data to the priority of providing the switching gaps. In some implementations, where the estimated time period exceeds the threshold, and/or the transport of queued data has a higher priority than providing the switching gaps, gNB-2_NW-1 may generate a switchSuspendIntervalValue (e.g., a timer value), where the switchSuspendIntervalValue is derived from, or is equivalent to, the interval of time (e.g., a suspension interval) needed to clear all of the data estimated to be queued at the UE, the data estimated to be queued at gNB-2_NW-1, and the data forwarded to the gNB-2_NW-1. In some implementations, where the switchSuspendIntervalValue is set to a non-zero value, the switching process of the UE is to suspend the switching process for some interval of time following the successful completion of the handover procedure of the UE from gNB-1_NW-1 to gNB-2_NW-1.
If, instead, where the estimated time period does not exceed the threshold, and/or the transport of queued data is of lower priority than providing the switching gaps, gNB-2_NW-1 may generate a switchSuspendIntervalValue indicating no suspension interval is needed (e.g., where the switchSuspendIntervalValue is set to zero). In such examples where the switchSuspendIntervalValue is set to zero (e.g., indicating no suspension interval is needed), the UE may be directed to not suspend the switching process following the successful completion of the handover procedure of the UE from gNB-1_NW-1 to gNB-2_NW-1.
Overall, in some implementations, the process by which gNB-2_NW-1 may determine whether to cause the UE to temporarily suspend gap switching operations for some suspension interval may include a number of operations:
Presuming a non-zero switchSuspendIntervalValue is generated (e.g., indicating that the gap switching process is to be temporarily suspended or paused immediately after completion of the handover procedure), as indicated in
Presuming, instead, that a zero switchSuspendIntervalValue is generated (e.g., indicating that the gap switching process is not to be temporarily suspended or paused after completion of the handover procedure), as indicated in
In some implementations, gNB-2_NW-1 may send the generated RRCReconfiguration message (e.g., possibly including the switchSuspendIntervalValue command to configure the switching procedure of the UE) to gNB-1_NW-1 at operation 230 of
In response to receiving the RRCReconfiguration message, gNB-1_NW-1 may allocate DL resources to the UE to provide information to the UE regarding the handover and the gap switching process at operation 232 of
Now referring to
During the handover procedure, as depicted in
Upon completion of the handover procedure, based on the switch procedure configuration performed by the UE (at operation 236 of
Further, in
In the case that the switching has not been paused after completion of the handover procedure, as illustrated in
In method portion 400A of
Collectively, operations 404 and 408 may confirm whether various conditions of the UE have been met before proceeding to the remainder of method portion 400A. For example, at operation 404, a determination may be made as to whether both USIM-A and USIM-B are enabled (e.g., in a state in which both USIM-A and USIM-B each may be used to access an associated network). If either USIM-A or USIM-B, or both, are disabled, method portion 400A may continue to execute operation 404 until both USIM-A and USIM-B are enabled. At operation 408, a determination may be made as to whether the UE has established a connected state (e.g., RRC_CONNECTED) with a base station of a network associated with either USIM-A (e.g., referred to in
At operation 410, the UE may obtain system timing information from the gNB with which the UE is in an RRC_IDLE state. In some implementations, the system timing information may include the frame structure, system timing, and/or system configuration information based on the UE's reception of PSS, SSS, MIB, SIB1, and/or SIB2 messages broadcast by the gNB in the RRC_IDLE state with the UE. At operation 412, the UE may determine a set of gap parameters from the obtained system timing information.
At operation 414, the UE may generate and transmit a request to the gNB with which the UE is in the RRC_CONNECTED state for one or more switch gap configurations based on the gap parameters. At operation 416, the UE, in response to the previously transmitted request, may receive the requested one or more switch gap configurations from the gNB with which the UE is in the RRC_CONNECTED state and then proceed to operation 418 of
In method portion 400B of
At operation 420, the UE may determine whether a handover command has been received (e.g., while the switching procedure of operation 418 is operating). If a handover command has not been received, the UE may proceed to operation 422. At operation 422, if the UE is in an RRC_CONNECTED state with either gNB-A or gNB-B, but not both (e.g., in a manner similar to operation 408), the UE may continue to wait for a handover command at operation 420 (e.g., while the switching procedure of operation 418 continues). Otherwise, the UE may proceed to operation 424, where the UE may stop the ongoing switching procedure, and to operation 425, where the UE may remove or cancel the switch gap configurations (e.g., from the gNB with which the UE was in an RRC_CONNECTED state), at which point method portion 400B may terminate.
If, instead, at operation 420, the handover command has been received, the UE may proceed to operation 426. At operation 426, the UE may determine whether the message that transported the handover command to the UE also transported a switchSuspendIntervalValue command. If the message did not include a switchSuspendIntervalValue command, the UE may return to operation 420 and may continue the switching procedure to switch to the gNB with which the UE is in the RRC_IDLE state without leaving the gNB with which the UE is in the RRC_CONNECTED state. If, instead, the message includes a switchSuspendIntervalValue command, the UE may proceed to operation 428. At operation 428, the UE may determine whether the switchSuspendIntervalValue command has a value of zero. If the switchSuspendIntervalValue command has a value of zero, the UE may return to operation 420 and may continue the switching procedure to switch to the gNB with which the UE is in the RRC_IDLE state without leaving the gNB with which the UE is in the RRC_CONNECTED state.
If the switchSuspendIntervalValue command has a non-zero value (at operation 428), the UE may proceed to operation 430. At operation 430, the UE may await completion of the handover procedure, at which time the UE may proceed to operation 432. At operation 432, the UE may suspend or pause the switching process to the gNB with which the UE is in the RRC_IDLE state. At operation 434, the UE may then configure a timer with the received switchSuspendIntervalValue and start the timer. Thereafter, at operation 436, the UE may await the expiration of the timer. When the timer expires, the UE may proceed to operation 418, where the UE may once again restart the switching process to the gNB with which the UE is in the RRC_IDLE state (e.g., according to the one or more switch gap configurations).
At operation 505, the source gNB may initiate the desired handover and determine whether the target gNB of the handover belongs to the same network as the source gNB. If not, the source gNB may exit method 500. Otherwise, the source gNB may proceed to operation 506.
At operation 506, the source gNB may transport, to the target gNB, a copy of the one or more switch gap configurations previously provided to the UE. In some implementations, the copy of the one or more switch gap configurations may be provided to the target gNB by way of a HANDOVER-REQUEST message to initiate the handover operation. In some implementations, the one or more switch gap configurations may be accompanied by information regarding current or previous data throughput and/or buffered data amounts, as described above. Method 500 may then proceed to operation 508.
At operation 508, the source gNB may receive a HANDOVER-REQUEST-ACKNOWLEDGE message from the target gNB in response to the earlier HANDOVER-REQUEST from the source gNB. At operation 510, the source gNB may transport, to the UE, an RRCReconfiguration message that was contained in the received HANDOVER-REQUEST-ACKNOWLEDGE message. As discussed above, the RRCReconfiguration message may include a switchSuspendIntervalValue command. Method 500 may then terminate.
At operation 604, the target gNB may evaluate the data throughput, the amount of data buffered, and/or other information received to generate a possible suspension interval value (e.g., a timer value, such as a switchSuspendIntervalValue) during which the UE may suspend or pause, for some interval, the switching procedure being used by the UE (e.g., in accordance with the one or more switch gap configurations) after completion of the handover procedure.
At operation 606, the target gNB may then compare the generated suspension interval value to some threshold value. If the generated suspension interval value is greater than the threshold, the target gNB may proceed to operation 612. At operation 612, the target gNB may generate an RRCReconfiguration message that includes a switchSuspendIntervalValue command that indicates the generated suspension interval value. Further, at operation 610, the target gNB may transmit, to the source gNB in response to the HANDOVER-REQUEST message, a HANDOVER-REQUEST-ACKNOWLEDGE message that includes the generated RRCReconfiguration message. Thereafter, method 600 may terminate.
If, instead, at operation 606, the generated suspension interval value is less than or equal to the threshold, the target gNB may proceed to operation 608. At operation 608, the target gNB may generate an RRCReconfiguration message that does not include a switchSuspendIntervalValue command. Alternately at operation 608, in some implementations, the target gNB may generate an RRCReconfiguration message that includes a switchSuspendIntervalValue of zero. Further, at operation 610, the target gNB may transmit, to the source gNB in response to the HANDOVER-REQUEST message, a HANDOVER-REQUEST-ACKNOWLEDGE message that includes the generated RRCReconfiguration message, after which method 600 may terminate.
The following example describes what operations the NR UE may perform upon reception of an RRCReconfiguration message with an otherConfig message that includes a new IE switchSuspendIntervalValue-r17, as an addition to the existing text in TS 38.331 (e.g., at Sections 5.3.5.3 and 5.3.5.9, with reference to Conditional Handover (CHO) and Conditional Primary Secondary Cell (PSCell) Change (CPC)):
This Nonprovisional application claims priority under 35 U.S.C. § 119 on provisional Application No. 63/247,566 on Sep. 23, 2021, the entire contents of which are hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/030740 | 8/12/2022 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63247566 | Sep 2021 | US |
