Patent Application
20230118032
The present application generally relates to wireless communications and, more specifically, relates to data packet delivery in a radio resource control (RRC) Inactive state.
The 3rd Generation Partnership Project (3GPP) has introduced a new radio resource control (RRC) state (i.e., RRC Inactive state) for the next generation (e.g., fifth generation (5G) or new radio (NR)) wireless communication networks. The RRC Inactive state aims to achieve power saving with acceptable access latency. When a user equipment (UE) is in the RRC Inactive state, the next generation radio access network (5G RAN) and the UE store the Access Stratum (AS) context (e.g., the UE context) separately. In addition, while in the RRC Inactive state, the UE may not have an RRC connection to the next generation RAN (e.g., 5G RAN), even though the next generation RAN may keep a connection with the next generation core network (CN) (e.g., 5G CN) for the UE. Other characteristics of the RRC Inactive state have been in development.
Thus, there is a need in the art for efficient packet delivery in the RRC Inactive state to reduce the signaling overhead, power consumption, and resource cost on both the UE side and the radio access network side.
The present disclosure is related to methods and apparatuses for data packet delivery in a radio resource control (RRC) Inactive state.
In a first aspect of the present disclosure, a method for wireless communication is provided. The method includes transmitting, by a User Equipment (UE) in a Radio Resource Control (RRC) Inactive (RRC_Inactive) state, at least one packet to a base station; and receiving, by the UE in the RRC_Inactive state, an acknowledgement or non-acknowledgement (ACK/NACK) message from the base station in response to the at least one packet transmitted by the UE.
According to an implementation of the first aspect, the ACK/NACK message includes an instruction to the UE to stay in the RRC Inactive state.
According to another implementation of the first aspect, the method further includes sending, by the UE, a random access preamble to the base station, wherein the random access preamble is associated with random access resources including time and/or frequency radio resources that are reserved for a plurality of UEs by the base station for packet transmission.
According to another implementation of the first aspect, the method further includes providing, by the UE, capability information to the base station, the capability information indicating whether the UE supports operations in the RRC_Inactive state.
According to another implementation of the first aspect, the method further includes receiving, by the UE, a pre-configured random access configuration in an RRC state configuration message; and applying, by the UE, the pre-configured random access configuration in a random access procedure to transmit the at least one packet to the base station, wherein the pre-configured random access configuration comprises at least one of a pre-configured bandwidth part (BWP) configuration, a plurality of access control parameters, a UE ID, and a time pattern of random access.
According to another implementation of the first aspect, the at least one packet includes an indicator indicating whether another packet is pending for transmission from the UE to the base station.
According to another implementation of the first aspect, the method further includes receiving, by the UE, information of additional uplink grant resources in the ACK/NACK message, when the indicator indicates that the another packet is pending for transmission from the UE to the base station, wherein the base station allocates the additional uplink grant resources to the UE for transmitting the another packet.
In a second aspect of the present disclosure, a UE is provided. The UE includes one or more non-transitory computer-readable media storing computer-executable instructions and at least one processor coupled to the one or more non-transitory computer-readable media. The at least one processor is configured to execute the computer-executable instructions to transmit, in a Radio Resource Control (RRC) Inactive (RRC_Inactive) state, at least one packet to a base station; and receive, in the RRC_Inactive state, an acknowledgement or non-acknowledgement (ACK/NACK) message from the base station in response to the at least one packet transmitted by the UE.
According to an implementation of the second aspect, the ACK/NACK message includes an instruction to the UE to stay in the RRC Inactive state.
According to another implementation of the second aspect, the at least one processor is further configured to execute the computer-executable instructions to send a random access preamble to the base station, wherein the random access preamble is associated with random access resources including time and/or frequency radio resources that are reserved for a plurality of UEs by the base station for packet transmission.
According to another implementation of the second aspect, the at least one processor is further configured to execute the computer-executable instructions to provide capability information to the base station, the capability information indicating whether the UE supports operations in the RRC_Inactive state.
According to another implementation of the second aspect, the at least one processor is further configured to execute the computer-executable instructions to receive a pre-configured random access configuration in an RRC state configuration message; and apply the pre-configured random access configuration in a random access procedure to transmit the at least one packet to the base station, wherein the pre-configured random access configuration comprises at least one of a pre-configured bandwidth part (BWP) configuration, a plurality of access control parameters, a UE ID, and a time pattern of random access.
According to another implementation of the second aspect, the at least one packet includes an indicator indicating whether another packet is pending for transmission from the UE to the base station.
According to another implementation of the second aspect, the at least one processor is further configured to execute the computer-executable instructions to receive information of additional uplink grant resources in the ACK/NACK message, when the indicator indicates that the another packet is pending for transmission from the UE to the base station, wherein the base station allocates the additional uplink grant resources to the UE for transmitting the another packet.
In a third aspect of the present disclosure, a method performed by a base station (BS) is provided. The method includes receiving, from a user equipment (UE), radio resource control (RRC) inactive state assistance information comprising capability information of the UE, the capability information indicating whether the UE is capable of transitioning to an RRC inactive state; and transmitting, to the UE, an RRC state configuration message for instructing the UE to transition to the RRC inactive state.
According to an implementation of the third aspect, the method further includes receiving, from the UE, an RRC connection resume request message; allocating one or more radio resources to the UE after receiving the RRC connection resume request message; and receiving, from the UE, at least one data packet on the allocated one or more radio resources, while the UE is in the RRC inactive state, wherein the BS identifies the UE for allocating the one or more radio resources and receiving the at least one data packet based on the received RRC connection resume request message.
According to another implementation of the third aspect, the method further includes, after receiving the at least one data packet, transmitting, to the UE, an RRC suspend message for instructing the UE to stay in the RRC inactive state.
According to another implementation of the third aspect, allocating the one or more radio resources to the UE comprises allocating the one or more radio resources to the UE via a random access response message.
According to another implementation of the third aspect, the at least one data packet includes an indicator indicating to the BS whether one or more uplink (UL) data packets are pending for transmission to the BS.
According to another implementation of the third aspect, the RRC state configuration message comprises a preconfigured random access configuration, the UE is configured to apply the preconfigured random access configuration in a random access procedure to transmit the at least one data packet to the BS, and the preconfigured random access configuration comprises at least one of a preconfigured bandwidth part (BWP) configuration, a plurality of access control parameters, a UE identifier (ID), and a time pattern of random access.
According to another implementation of the third aspect, the plurality of access control parameters comprises one or more logical channels enabled to be transmitted via the at least one data packet, while the UE is in the RRC inactive state.
According to another implementation of the third aspect, the UE transmits the at least one data packet to the BS by accessing at least one grant-free resource, which is part of the preconfigured bandwidth part (BWP) configuration.
In a fourth aspect of the present disclosure, a BS is provided. The BS includes one or more non-transitory computer-readable media storing one or more computer-executable instructions and at least one processor coupled to the one or more non-transitory computer-readable media. The at least one processor is configured to execute the computer-executable instructions to receive, from a user equipment (UE), radio resource control (RRC) inactive state assistance information comprising capability information of the UE, the capability information indicating whether the UE is capable of transitioning to an RRC inactive state; and transmit, to the UE, an RRC state configuration message for instructing the UE to transition to the RRC inactive state.
In a fifth aspect of the present disclosure, a UE is provided. The UE includes one or more non-transitory computer-readable media storing one or more computer-executable instructions and at least one processor coupled to the one or more non-transitory computer-readable media. The at least one processor is configured to execute the computer-executable instructions to transmit, to a base station (BS), radio resource control (RRC) inactive state assistance information comprising capability information of the UE, the capability information indicating to the BS whether the UE is capable of transitioning to an RRC inactive state; receive, from the BS, an RRC state configuration message; and transition to the RRC inactive state after receiving the RRC state configuration message.
According to an implementation of the fifth aspect, the RRC state configuration message comprises a preconfigured random access configuration, the UE is configured to apply the preconfigured random access configuration in a random access procedure to transmit the at least one data packet to the BS, and the preconfigured random access configuration comprises at least one of a preconfigured bandwidth part (BWP) configuration, a plurality of access control parameters, a UE identifier (ID), and a time pattern of random access.
According to another implementation of the fifth aspect, the plurality of access control parameters comprises one or more logical channels enabled to be transmitted via the at least one data packet while the UE is in the RRC inactive state.
According to another implementation of the fifth aspect, the UE transmits the at least one data packet to the BS by accessing at least one grant-free resource, which is part of the preconfigured bandwidth part (BWP) configuration.
Aspects of the exemplary disclosure are best understood from the following detailed description when read with the accompanying Figures. Various features are not drawn to scale, dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.
The following description contains specific information pertaining to implementations in the present application. The drawings in the present application and their accompanying detailed description are directed to merely exemplary implementations. Unless noted otherwise, like or corresponding elements among the figures may be indicated by like or corresponding reference numerals. Moreover, the drawings and illustrations in the present application are generally not to scale, and are not intended to correspond to actual relative dimensions.
For the purpose of consistency and ease of understanding, like features are identified (although, in some examples, not shown) by numerals in the exemplary figures. However, the features in different implementations may be differed in other respects, and thus shall not be narrowly confined to what is shown in the figures.
The description uses the phrases “in one implementation,” or “in some implementations,” which may each refer to one or more of the same or different implementations. The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The term “comprising,” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series and the equivalent.
Additionally, for the purposes of explanation and non-limitation, specific details, such as functional entities, techniques, protocols, standard, and the like are set forth for providing an understanding of the described technology. In other examples, detailed description of well-known methods, technologies, system, architectures, and the like are omitted so as not to obscure the description with unnecessary details.
Persons skilled in the art will immediately recognize that any network function(s) or algorithm(s) described in the present disclosure may be implemented by hardware, software or a combination of software and hardware. Described functions may correspond to modules may be software, hardware, firmware, or any combination thereof. The software implementation may include computer executable instructions stored on computer readable medium such as memory or other type of storage devices. For example, one or more microprocessors or general purpose computers with communication processing capability may be programmed with corresponding executable instructions and carry out the described network function(s) or algorithm(s). The microprocessors or general purpose computers may be formed of applications specific integrated circuitry (ASIC), programmable logic arrays, and/or using one or more digital signal processor (DSPs). Although some of the exemplary implementations described in this specification are oriented to software installed and executing on computer hardware, nevertheless, alternative exemplary implementations implemented as firmware or as hardware or combination of hardware and software are well within the scope of the present disclosure.
The computer readable medium includes but is not limited to random access memory (RAM), read only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, compact disc read-only memory (CD ROM), magnetic cassettes, magnetic tape, magnetic disk storage, or any other equivalent medium capable of storing computer-readable instructions.
A radio communication network architecture (e.g., a long term evolution (LTE) system, a LTE-Advanced (LTE-A) system, or a LTE-Advanced Pro system) typically includes at least one base station, at least one user equipment (UE), and one or more optional network elements that provide connection towards a network. The UE communicates with the network (e.g., a core network (CN), an evolved packet core (EPC) network, an Evolved Universal Terrestrial Radio Access network (E-UTRAN), a Next-Generation Core (NGC), or an internet), through a radio access network (RAN) established by the base station.
It should be noted that, in the present application, a UE may include, but is not limited to, a mobile station, a mobile terminal or device, a user communication radio terminal. For example, a UE may be a portable radio equipment, which includes, but is not limited to, a mobile phone, a tablet, a wearable device, a sensor, or a personal digital assistant (PDA) with wireless communication capability. The UE is configured to receive and transmit signals over an air interface to one or more cells in a radio access network.
A base station may include, but is not limited to, a node B (NB) as in the LTE, an evolved node B (eNB) as in the LTE-A, a radio network controller (RNC) as in the UMTS, a base station controller (BSC) as in the GSM/GERAN, a new radio evolved node B (NR eNB) as in the NR, a next generation node B (gNB) as in the NR, and any other apparatus capable of controlling radio communication and managing radio resources within a cell. The base station may connect to serve the one or more UEs through a radio interface to the network.
A base station may be configured to provide communication services according to at least one of the following radio access technologies (RATs): Worldwide Interoperability for Microwave Access (WiMAX), Global System for Mobile communications (GSM, often referred to as 2G), GSM EDGE radio access Network (GERAN), General Packet Radio Service (GRPS), Universal Mobile Telecommunication System (UMTS, often referred to as 3G) based on basic wideband-code division multiple access (W-CDMA), high-speed packet access (HSPA), LTE, LTE-A, New Radio (NR, often referred to as 5G), and/or LTE-A Pro. However, the scope of the present application should not be limited to the above mentioned protocols.
The base station is operable to provide radio coverage to a specific geographical area using a plurality of cells forming the radio access network. The base station supports the operations of the cells. Each cell is operable to provide services to at least one UE within its radio coverage. More specifically, each cell (often referred to as a serving cell) provides services to serve one or more UEs within its radio coverage, (e.g., each cell schedules the downlink and optionally uplink resources to at least one UE within its radio coverage for downlink and optionally uplink packet transmissions). The base station can communicate with one or more UEs in the radio communication system through the plurality of cells. A cell may allocate sidelink (SL) resources for supporting proximity service (ProSe). Each cell may have overlapped coverage areas with other cells.
As discussed above, the frame structure for NR is to support flexible configurations for accommodating various next generation (e.g., 5G) communication requirements, such as enhanced mobile broadband (eMBB), massive machine type communication (mMTC), ultra reliable communication and low latency communication (URLLC), while fulfilling high reliability, high data rate and low latency requirements. The orthogonal frequency-division multiplexing (OFDM) technology as agreed in 3GPP may serve as a baseline for NR waveform. The scalable OFDM numerology, such as the adaptive sub-carrier spacing, the channel bandwidth, and the Cyclic Prefix (CP) may be also used. Additionally, two coding schemes are considered for NR: (1) low-density parity-check (LDPC) code and (2) Polar Code. The coding scheme adaption may be configured based on the channel conditions and/or the service applications.
Moreover, it is also considered that in a transmission time interval TX of a single NR frame, a downlink (DL) transmission data, a guard period, and an uplink (UL) transmission data should at least be included, where the respective portions of the DL transmission data, the guard period, the UL transmission data should also be configurable, for example, based on the network dynamics of NR. In addition, sidelink resource may also be provided in a NR frame to support ProSe services.
Referring to
As shown in
In this implementation, RRC Inactive state 164B is regarded as one sub-state of RRC Connected state 162B. As shown in
In the present application, a UE may undergo RRC state transitions, following the RRC state transition procedures in
In the present application, a radio access network (RAN) (e.g., 5G-RAN or NR-RAN) may configure a UE to send an RRC Resume Request during either a 2-step or a 4-step random access procedure. Before a random access procedure, however, it is also worthy to note that a RAN (e.g., the last serving base station, such as a gNB, which instructs the UE to move to RRC Inactive state) may pre-configure the random access configuration.
In accordance with implementations of the present application, a base station may configure a UE in RRC Inactive state to realize a 2-step random access procedure or a 4-step random access procedure.
In action 322 of random access procedure 320, an RRC Inactive UE 302 may send MSG1 to base station 306 of a radio access network (e.g., RAN 204 in
In action 324, UE 302 may transmit data packet(s) (e.g., small data packet(s)) on radio resources (e.g., DRBs or logical channels) indicated in the pre-configured random access configuration.
After base station 306 receives the data packet(s) from UE 302, in action 326, base station 306 may send MSG2 to UE 302, where MSG2 may include a Random Access Response message (e.g., ACK/NACK message) to UE 302. In one implementation, MSG2 may also include an RRC suspend message, such that RRC Inactive UE 302 may perform uplink data packet transmission without transitioning to RRC Connected state, thereby reducing network signaling overhead and conserving radio resource. In another implementation, MSG2 may include a Random Access Response message having an RRC Resume message, which may cause UE 302 to transition from RRC Inactive state to RRC Connected state.
In action 332 of random access procedure 330, an RRC Inactive UE 302 may send MSG1 to base station 306 of a radio access network (e.g., RAN 204 in
In action 334, after base station 306 (and the associated RAN) receives the Preamble, base station 306 may send MSG2 to UE 302. MSG2 may include a Random Access Response. In one implementation, MSG2 may provide time advance and resource grant for at least one Signaling Radio Bearer (e.g., SRB0) and/or at least one Data Radio Bearer (DRB) or logical channel for UE 302 to deliver an RRC Connection Resume Request and data packet(s) (e.g., small data packet(s)), for example, in MSG3. In one implementation, each DRB may be mapped to a corresponding logical channel in the pending packet scheduling, such that there is a one-to-one mapping relationship between a DRB and a logical channel.
In action 336, RRC Inactive UE 302 may send MSG3 to base station 306. MSG3 may include an RRC Connection Resume Request, having an RRC Resume ID provided by base station 306, for example, using SRB0.
In addition, in action 338, UE 302 may also transmit data packet(s) (e.g., small data packet(s)) on indicated resource grant (e.g., radio resources granted by base station 306 in action 334). In some implementations, base station 306 may only provide UL grant for UE 302 to transmit SRB signaling, and UE 302 may transmit data of DRB(s) in grant-free resource pools. The configurations of grant-free resource pools are provided by base station 306 through broadcasting (e.g., system information) or in the random access configuration. In some implementations, the grant-free resource pools are periodical radio resources in time domain, for example, as illustrated in
After base station 306 receives the data packet(s) from UE 302, in action 340, base station 306 may send MSG4 to UE 302, where MSG4 may include an RRC Response message (e.g., ACK/NACK message) to UE 302. In one implementation, MSG4 may also include an RRC suspend message, such that RRC Inactive UE 302 may perform uplink data packet transmission without transitioning to RRC Connected state, thereby reducing network signaling overhead and conserving radio resource. In another implementation, MSG4 may include a Random Access Response message having an RRC Resume message, which may cause UE 302 to transition from RRC Inactive state to RRC Connected state.
In
In action 352 of random access procedure 350, an RRC Inactive UE 302 may send MSG1 to base station 306 of a radio access network (e.g., RAN 204 in
In action 354, after base station 306 (and the associated RAN) receives the RRC Connection Resume Request, base station 306 may send MSG2 to UE 302. MSG2 may include an RRC Connection Resume Response message. In one implementation, MSG2 may provide time advance and resource grant for at least one Data Radio Bearer (DRB) or logical channel for UE 302 to deliver data packet(s) (e.g., small data packet(s)), for example, in MSG3. In one implementation, each DRB may be mapped to a corresponding logical channel in the pending packet scheduling, such that there is a one-to-one mapping relationship between a DRB and a logical channel. In one implementation, MSG2 may also include one or more bandwidth part (BWP) configuration indices, for example, corresponding to one or more pre-configured BWP configurations based on the pre-configured random access configuration. Based on the BWP indices from base station 306, UE 302 may apply the corresponding BWP configuration (e.g., pre-configured BWP configuration stored on UE 302) for the subsequent UL data packet transmission.
In addition, in action 356, UE 302 may transmit data packet(s) (e.g., small data packet(s)) on indicated resource grant (e.g., radio resources, such as DRBs and/or logical channels, granted by base station 306 in action 354).
After base station 306 receives the data packet(s) from UE 302, in action 358, base station 306 may send MSG4 to UE 302, where MSG4 may include ACK/NACK message to UE 302. In one implementation, MSG4 may also include an RRC suspend message, such that RRC Inactive UE 302 may perform uplink data packet transmission without transitioning to RRC Connected state, thereby reducing network signaling overhead and conserving radio resource. In another implementation, MSG4 may include an RRC Resume message, which may cause UE 302 to transition from RRC Inactive state to RRC Connected state.
It should be noted that, in
As mentioned with reference to
A pre-configured random access configuration may include at least one of the following objects:
Table 1 shows parameters that can be included in a pre-configured random access configuration.
Table 2 shows exemplary mapping rules between CE levels and the values of packet repetition, where the mapping rules may be included in the random access configuration. Mcell is a UE's measurement report, and {Mcell,Q1˜Q4} may be RSRP, RSRQ, RSSI, SINR and so their units may be dB (for RSRP, RSRQ, SINR) or dBm (for RSSI).
A UE may implement a random access procedure based on stored pre-configured random access configuration(s). For example, in a random access procedure, a default BWP configuration and/or a pre-configured BWP configuration may be provided to the UE.
In some implementations, the UE may obtain the default BWP configuration through broadcast signal (e.g., system information) from a base station (e.g., gNB), and the pre-configured BWP configuration through the pre-configured random access configuration. In the beginning of a random access procedure, the UE may apply random access on the default BWP since the base station may not recognize the UE before the base station receives a UE-specific MSG1 or a UE ID in MSG3. As note that, in some other implementations, the UE may be configured with more than one pre-configured BWP configuration in the pre-configured random access configuration and each pre-configured BWP would have a BWP-index in the random access configuration.
After the base station identifies the UE (e.g., gNB receives UE identity in MSG1 (or MSG3), the base station may provide UL grant (e.g., in MSG2 or MSG4 transmission of a 4-step random access procedure) and control parameters (e.g., TA) based on the pre-configured BWP. Also note, in the implementations which more than one pre-configured BWP configuration is in the random access configuration, the base station may further indicate which pre-configured BWP configuration that the UE should apply in the subsequent random access procedure (e.g., by indicating a BWP index of the corresponding BWP configuration in MSG2 or MSG4 transmission of a 4-step random access procedure).
In addition, after the base station identifies the UE, the UE may apply the pre-configured BWP for subsequent message exchange with the base station.
In some other implementations, the UE may not be provided with pre-configured BWP in the pre-configured random access configuration. As such, the default BWP configuration, for example, broadcast by the base station through system information, may be applied for the entire random access procedure for the UE. In either a default or pre-configured BWP, the UE may apply random access procedure based on a configured numerology, a given frequency location, a UL waveform, and a bandwidth. The BWP configuration may affect the basic granularity of radio frame structure, such as the time/frequency span of one symbol, one slot, and one physical radio block, etc.
A default BWP configuration is provided to a UE, for example, through system information broadcast by a base station. The UE and base station may exchange MSG1 and MSG2 using the default BWP configuration. If a pre-configured BWP configuration is provided to the UE through an RRC Connection Release message (e.g., in action 212A/212B in
As illustrated in
In some implementations, a base station may only provide UL grant for UE to transmit SRB signaling, and the UE may transmit data of DRB (s) in grant-free resource pools. The configurations of grant-free resource pools are provided by the base station, for example, through broadcasting (e.g., system information) or in the random access configuration. In some implementations, the grant-free resource pools are periodical radio resources in time domain, for example, as illustrated in
As illustrated in
With reference to
In one implementation, in a 2-step random access procedure, MSG1 may include a pre-defined preamble. The UE identity may be shown by the pre-defined preamble and/or PRBs, which are pre-configured by RAN, before the UE transitioned into RRC Inactive state, for example, in a pre-configured random access configuration, such as the ones shown in
In another implementation, in a 4-step random access procedure, a UE may not include a UE identity in MSG1, but may inform a base station about the amount of pending uplink data by preamble selection. The amount of pending uplink data may include the control signaling (e.g., RRC signaling) and UL data available for transmission plus MAC header and, where required, MAC control elements. In addition, the UL data available may be limited by the specific conditions of the logical channel(s), which is configured by the RAN in the random access configuration. In some implementations, the UE may calculate the amount of pending uplink data by jointly multiplying the number of repetition values for the pending packets.
In this approach, the UE may select a preamble based on the selection rules in Table 3. As shown in Table 3, all preambles may be further divided into several preamble groups. Each preamble group includes at least one preamble. The UE may first select a preamble group based on the calculated pending uplink data amount. Then, the UE may select a preamble from the selected preamble group, for example, autonomously. In Table 3, the unit of pending uplink data amount (D) and the thresholds {TA, TB, TC . . . TJ} are represented by bytes.
In yet another implementation, in a 4-step random access procedure, a UE may select a preamble from many candidate preambles, for example, autonomously. The UE may send the selected preamble in MSG1 without conveying any additional information.
In yet another implementation, as shown in
As shown in
The UL data available may be limited by the specific conditions of the logical channel(s), which is configured by the RAN in the random access configuration. During the random access procedure, the UE may be allowed to transmit only the pending packets of the logical channels configured in the random access configuration. Thus, when calculating the pending uplink data amount, the UE may only need to calculate the pending packets of the configured logical channels, which are enabled by the base station to be transmitted through the random access procedure. By contrast, logical channels that are not configured by the RAN may not be included in the calculation of the pending uplink data amount. In Table 4, the unit of data amount (D) and the thresholds {Ta, Tb, Tc . . . Tj} are represented by bytes.
In yet another implementation, as shown in
It should be noted that in some implementations, MSG1 may be transmitted on the default BWP, for example, broadcast by a serving base station. In some other implementations, MSG1 may be transmitted on pre-configured BWP configured in the random access configuration. The default BWP configuration configured by the serving base station may have a higher priority, if the UE has both the default BWP configuration and the pre-configured BWP configuration from the random access configuration.
Referring back to
In a situation where the base station obtains the pending uplink data amount after receiving MSG1 from the UE, the base station may provide uplink grant for the UE to transmit MSG3 based on the pending uplink data amount. Otherwise, the base station may provide a fixed amount of UL grant to the UE if the pending uplink data amount is not provided in MSG1. To the UE, the UE may know that MSG1 delivery (and the embedded information) is recognized by the base station after the UE receives MSG2 successfully. Then, the UE may prepare for MSG3 delivery based on the UL grant in MSG2. Otherwise, the UE may consider that MSG1 transmission to the base station has failed, for example, if the UE does not receive MSG2 within a predetermined time period after MSG1 transmission. In a 2-step random access procedure, the UE may transmit UL data packets on grant-free resource pools, which may be configured on random access configuration based on a pre-configured BWP configuration (if there is one). Otherwise, the grant-free resource pools may be provided through serving base station based on a default BWP configuration. In a 4-step random access procedure, the UL grant in MSG2 may be provided based on a default BWP configuration.
The base station may decide uplink TA for the UE to transmit MSG3 and the subsequent uplink message. In a 4-step random access procedure, the base station may decide the granularity of TA if the RAN has a pre-configured BWP configuration of MSG3 to the UE in the random access configuration. For example, the base station may decide the granularity of TA based on the subcarrier spacing of MSG3 transmission. Otherwise, the base station may indicate the UE's TA based on a default granularity (e.g., the default granularity decided based on the default BWP configuration).
In some implementations, MSG2 may be transmitted on the default BWP configured by the serving the base station (e.g., in a 2-step random access procedure). In some other implementations, MSG2 are transmitted on the configured-BWP configured in the random access configuration (e.g., in a 4-step random access procedure).
Referring back to
The UE may transmit MSG3 based on BWP configuration, which may include numerology, UL waveform, bandwidth, and frequency location. In a 4-step random access procedure, the base station may identify the UE through MSG1 (e.g., as shown in
In a 4-step random access procedure, the base station may recognize the UE after receiving MSG3 (e.g., as shown in
In some implementations, only one default BWP is applied to the random access procedure. In this condition, the UL grant is provided based on default BWP and the UE may transmit RRC Resume Request message and the following UL packets to the base station based on the default BWP directly. The base station may also decode MSG3 based on the default BWP configuration.
In MSG2, the base station may provide UL grant across multiple scheduling units.
In the random access configuration, the UE decides the MSG3 transmission by considering the logical channels that are allowed to transmit data through the random access procedure. In addition, the UE may also repeat each packet if a repetition value is configured with the logical channel. In some other implementations, the UE may decide the value of packet repetition by the measurement results of the serving base station.
In each RB, the UE may add a one-bit indicator (e.g., one-bit end of transmission (“EoT”) bit) to indicate the end of transmission or to indicate continuation to the next RB transmission. Therefore, in some implementations, the UE may set EoT=0 if there are still some pending packets.
When the base station receives a packet having EoT=0 from the UE, in one implementation, the base station may allocate additional UL grant resource(s) to the UE for the subsequent UL packet transmission, if the UE needs more radio resource to finish UL packet transmission. The base station may allocate additional UL grant to the UE with the ACK message and RRC Connection Resume Response message in MSG4.
When the base station receives a packet having EoT=0 from the UE, in another implementation, the base station may require the UE to transition to RRC Connected state, instead of staying RRC Inactive state, for the subsequent packet transmission. The UE may set EoT=1 when transmitting the last pending packet to the base station. Then, the base station may send an RRC Suspend message to let the UE transition back to RRC INACTIVE state and disconnect with the base station. If there are remaining PRBs which are not used by the UE, the base station may schedule the un-used PRBs may for other UEs.
It should be noted that, the UE may not transmit the EoT bit with a UL packet if the base station disables the continuous RB transmissions in MSG3.
Referring back to
Referring now to
In diagram 1000 of
In some implementations, N1 may be pre-configured by the base station (e.g., in the pre-configured random access configuration) before the random access procedure, and so the value of N1 may be UE-specific. As such, the base station may identify UE after receiving MSG1 and knows the time limit for transmitting MSG2.
In some implementations, the value of N1 may be a fixed value in the technical specification or may be conducted by receiving broadcasted signaling (e.g., system information) from the base station. For example, the system information may indicate the default numerology for the random access procedure. A default BWP (and so a default numerology) may include sub-carrier-spacing, cyclic-prefix length, and etc. Thus, the default BWP configuration may affect the value of symbols and slots in the frame structure. In addition, the granularity of N1 may be one or multiple symbols (e.g., 1-7 symbols in time domain), one or multiple time slots, or one or multiple subframes.
It is also noted that the design of N1 can be generally applied to both the 2-step and 4-step random access procedures.
In diagram 1000 of
In some implementations, there is a group of uplink messages in MSG3. As described above with reference to
In some implementations, the base station may configure multiple RBs for the UE based on a slot aggregation approach. As such, the scheduling units {S #i, S #j, S #k, . . . S #m, S #n} are contiguous to each other. In addition, the value of each of {N2a, N2b, . . . N2j} is equivalent to the time duration of one time slot.
In diagram 1000 of
In a 4-step random access procedure, N1, N2, and N3 may be pre-configured by the base station (e.g., through dedicated signaling, such as RRC signaling) in the random access configuration. The value of each of N1, N2, and N3 may be UE-specific. The base station may identify the UE after receiving MSG1. As such, the base station knows the values of N1, N2, and N3 since they are pre-configured. In another 4-step random access procedure, the values of N1, N2, and N3 may be fixed, and be decided by a default BWP configuration.
A base station may configure RRC Inactive state access control parameters in the random access configuration. To prevent congestion of random access resource, the base station may configure a prohibit timer to an UE transitioning to RRC Inactive state. The UE in RRC Inactive state may activate the prohibit timer, Pac, (e.g., having a unit: second/millisecond), when the base station sends an RRC Response message (e.g., RRC Suspend message to the UE) to finish a random access procedure. The UE may not be allowed to trigger a random access procedure just for another UL packet transmission (as shown in
In some other implementations, a threshold data amount, Dac, (unit: bytes) is provided to prevent congestion of random access resource. Based on the
In some other implementations, the base station will provide a threshold (Tac). An RRC Inactive UE may generate a random value within a pre-defined range. For example, the UE may randomly select a value within the range (0,1), where (0,1) is pre-defined by the RAN. Then, the UE may compare with the random value with the threshold, Tac. In one implementation, the UE may be allowed to trigger a random access procedure for UL packet transmission, if the random value is higher than the Tac. Otherwise, the UE may re-activate the prohibit timer, Pac, and re-generate another random value to compare with the threshold, Tac, after the prohibit timer expires. In another implementation, the UE may be allowed to trigger a random access procedure for UL packet transmission, if the random value is lower than (or equal to) the Tac. The value of Tac may be UE-specific or logical channel-specific.
In yet some other implementations, the transmission latency of UL packets may be more critical. Thus, the base station may configure the latency threshold, Lac, for an RRC Inactive UE. Thus, the RRC Inactive UE may establish an RRC connection with the base station, when the waiting time of the UL packets in the UE's buffer is longer than the configured latency threshold, Lac. The value of Lac may be UE-specific or logical channel specific, which means different logical channels may be provided with different priorities. Thus, the base station may provide different Lac values in the random access configuration for different logical channels.
In yet some other implementations, another threshold data amount, D′ac, (unit: bytes) may also be configured to the UE. The UE may establish an RRC connection for packet transmission if the amount of pending packet is higher than D′ac and if UE can't transmit pending packets successfully through random access procedure. The value of D′ac may be UE-specific or logical channel-specific.
In some implementations, a base station may deliver downlink (DL) packets (e.g., DL small packets) to UEs in RRC Inactive state.
Base station 1206 may configure a specific UE ID, which is provided for DL packet transmission, to UE 1202. In some implementations, the specific UE ID may be the RRC Resume ID (or truncated RRC Resume ID). Moreover, base station 1206 may also configure a UE-specific MSG1 for DL small data transmission. Both the specific UE ID and the UE-specific MSG1 may be configured in the RRC state configuration message.
Base station 1206 may inform, by delivering the specific UE ID of the UE 1202 in the paging message, in action 1210, UE 1202 at RRC Inactive state to perform DL packet transmission. In this implementation, UE 1202 may not transition to an RRC Connected state for performing the DL packet transmission. Then, in action 1212, UE 1202 may deliver the UE-specific MSG1 to base station 1206, which allows base station 1206 to identify UE 1202 by the UE-specific MSG1.
In some implementations, base station 1206 may provide one-bit indicator (e.g., by setting the indicator to 1) in the paging message to UE 1202, which allows UE 1202 to perform DL packet transmission without transiting to RRC Connected state and to send the UE-specific MSG1 after receiving the paging message.
In action 1214, base station 1206 may deliver a RAR response, containing timing advance information, DL scheduling information for DL packet transmissions, and UL resource grant for UE 1202 to send ACK/NACK message to base station 1206. UE 1202 may decode the RAR message in response to the information in the paging message (e.g., a gNB pages UE 1202 based on a UE-specific ID/RRC Resume ID or one-bit indicator to inform UE 1202 to receive the RAR response for DL packet transmission). In action 1216, UE 1202 may receive the DL packets directly. After DL packet transmission is completed, UE 1202 may send ACK/NACK messages to base station 1206 in action 1218. In the DL scheduling information, base station 1206 may further indicate which pre-configured BWP configuration (e.g., through BWP-index if there are more than one pre-configured BWP configurations) would be applied for the following DL packet transmission. Otherwise, the following DL packet transmission would be transmitted based on default BWP.
Therefore, in order to enable the DL packet transmission for UEs in RRC Inactive state, the base station may need to configure a UE-specific ID/UE-specific MSG1 for DL packet transmission. Thus, when the UE finds the configured UE-specific ID in the paging message, the UE will stop doing state transition for the following DL packet transmission. Moreover, the base station may configure the UE with another UE-specific ID in the RRC state configuration message. Therefore, the UE may require RRC Connection establishment or RRC Connection Resume Request after receiving the specific ID in paging message. In some other implementations, the eNB may provide an indicator (e.g., one bit) to indicate the UE to implement RRC Connection establishment (e.g., indicator is set to 0) or RRC Connection Resume Request or DL packet reception (e.g., indicator is set to 1).
As shown in
Based on implementations of the present application, a base station may determine a UE's RRC state through following inputs: (a) input from the core network; (b) input from the UE; (c) self-observation from the base station.
(a) Input from the Core Network (CN)
In some implementations, a base station determines a UE's RRC state in response to the input, (e.g., network slice instances), from the CN. The CN may deliver the network slice instance information of the UE to the base station. Then, the base station may configure the UE's RRC states in response to the received network slice instance of the UE.
In one implementation, the base station may configure RRC Connected state or RRC Idle state to the UE, for example, when eMBB network slice instance is generated to UE. In another implementation, the base station may configure RRC Connected state/RRC Idle state/RRC Inactive state to the UE, for example, when URLLC network slice instance is generated to the UE. In another implementation, the base station may configure an RRC Connected state, an RRC Idle state, or an RRC Inactive state to the UE when mMTC network slice instance is generated to the UE.
Thus, a base station may configure an RRC Connected state, an RRC Idle state, or an RRC Inactive state to a UE including an mMTC network slice instance. In contrast, the network may only configure an RRC Connected state or an RRC Idle state to a UE including an eMBB network slice instance.
Moreover, a UE may be configured with multiple network slice instances. In one implementation, the network may consider the RRC state configuration of the UE by jointly considering the UE′ network slice instances. For example, the UE may be configured with an eMBB network slice instance and a mMTC network slice instance. Therefore, the network may still configure an RRC Connected state, an RRC Idle state, or an RRC Inactive state to UE 1302 configured with the eMBB and the mMTC network slice instances respectively.
(b) Input from the UE
In some implementations, a UE may have specific preferences including UE's needs for data rate boost, short latency, and/or power lifetime extension. Thus, the UE may send an RRC Inactive state request to the base station which indicates whether the UE requires RRC Inactive state and cause events including data rate boost, short latency, or power lifetime extension, etc. The RRC Inactive state request may be an explicit RRC message (e.g., an RRC Connection reconfiguration message, an RRC Connection Release message or a new RRC message) or a MAC Control element (MAC CE). In some implementations, the RRC Inactive state request may be included in a UE Capability Information message sent to the base station. As shown in
(c) Self-Observation from the Base Station
A base station may configure RRC states in response to traffic characteristics (e.g., inter-arrival time of packets, traffic volume, UE's mobility state, UE speed, etc.) of a UE. In some implementations, the RRC state configuration message may be a cell-specific control signaling. In one implementation, the base station may deliver the RRC state configuration message to the UE during a handover process. In another implementation, a base station may broadcast an RRC state configuration message (e.g., through system information, Physical Downlink Control Channel, or Enhanced Physical Downlink Control Channel).
In some implementations, a base station is able to configure the RRC states of a UE. In one implementation, a base station may explicitly indicate the enabled RRC states to the UE through an RRC state configuration message including an RRC Connected state, an RRC Idle state, or an RRC Inactive state.
In another implementation, an RRC Connected state, an RRC Idle state, or an RRC Inactive state are installed in the software modules of a UE. Then, a base station may deliver the RRC state configuration message to the UE to disable the RRC Inactive state transition of the UE. As such, after receiving the RRC state configuration message, the UE may disable RRC Inactive state. In contrast, the base station may also deliver the RRC state configuration message to enable the state transition about RRC Inactive state if RRC Inactive state is disabled by the network previously. If RRC Inactive state is disabled by default, the base station needs to deliver an RRC state configuration message to enable RRC Inactive state. Moreover, the UE may fallback to default RRC states when the UE reboots. Thus, the base station may need to deliver an RRC state configuration message to the UE during an initial access process.
Transceiver 1420 having transmitter 1422 and receiver 1424 may be configured to transmit and/or receive time and/or frequency resource partitioning information. In some implementations, transceiver 1420 may be configured to transmit in different types of subframes and slots including, but not limited to, usable, non-usable and flexibly usable subframes and slot formats. Transceiver 1420 may be configured to receive data and control channels.
Node 1400 may include a variety of computer-readable media. Computer-readable media can be any available media that can be accessed by node 1400 and include both volatile and non-volatile media, removable and non-removable media. By way of example, and not limitation, computer-readable media may include computer storage media and communication media. Computer storage media includes both volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or other data.
Computer storage media includes RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices. Computer storage media does not include a propagated data signal. Communication media typically embodies computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer-readable media.
Memory 1428 may include computer-storage media in the form of volatile and/or non-volatile memory. Memory 1428 may be removable, non-removable, or a combination thereof. Exemplary memory includes solid-state memory, hard drives, optical-disc drives, and etc. As illustrated in
Processor 1426 may include an intelligent hardware device, e.g., a central processing unit (CPU), a microcontroller, an ASIC, and etc. Processor 1426 may include memory. Processor 1426 may process data 1430 and instructions 1432 received from memory 1428, and information through transceiver 1420, the base band communications module, and/or the network communications module. Processor 1426 may also process information to be sent to transceiver 1420 for transmission through antenna 1436, to the network communications module for transmission to a core network.
One or more presentation components 1434 presents data indications to a person or other device. Exemplary one or more presentation components 1434 include a display device, speaker, printing component, vibrating component, and etc.
From the above description it is manifest that various techniques can be used for implementing the concepts described in the present application without departing from the scope of those concepts. Moreover, while the concepts have been described with specific reference to certain implementations, a person of ordinary skill in the art would recognize that changes can be made in form and detail without departing from the scope of those concepts. As such, the described implementations are to be considered in all respects as illustrative and not restrictive. It should also be understood that the present application is not limited to the particular implementations described above, but many rearrangements, modifications, and substitutions are possible without departing from the scope of the present disclosure.
This application is a continuation application of U.S. patent application Ser. No. 16/900,802, filed on Jun. 12, 2020, published as U.S. Publication No. 2020/0314893, which is a continuation application of U.S. patent application Ser. No. 15/809,238, filed on Nov. 10, 2017, issued as U.S. Pat. No. 10,728,927, which claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/420,588, filed on Nov. 11, 2016, the contents of all of which are hereby incorporated herein fully by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 62420588 | Nov 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16900802 | Jun 2020 | US |
| Child | 18082111 | US | |
| Parent | 15809238 | Nov 2017 | US |
| Child | 16900802 | US |
