Uplink transmission on a contention-based bandwidth part

Abstract

A method in a UE for transmitting data via a contention-based BWP in an idle state of a protocol for controlling radio resources can be performed by one or more processors. The method includes determining that the UE has time alignment with a base station for uplink transmissions to the base station (602), determining that a time resource for the uplink transmissions is available on the contention-based BWP (604), and transmitting data within the time resource according to the time alignment while the UE is in the idle state (606).

Description

Technical Field

[0001] This disclosure generally relates to wireless communications, and more specifically, to managing uplink transmissions on contention-based bandwidth portions (BWPs). Background Technology

[0002] This background description is provided to present the overall context of this disclosure. The work of the currently named inventors within the scope described in this background section, as well as aspects that may not conform to the description as prior art at the time of filing, are neither explicitly nor implicitly acknowledged as prior art relative to this disclosure.

[0003] 5G New Radio (NR) base stations can configure user equipment (or user equipment, "UE") to operate within a specific bandwidth portion (BWP) or a portion of a wide carrier bandwidth. Specification 3GPP TS 38.211 Release 15.3.0 defines a BWP as a contiguous set of physical resource blocks on a given carrier. As a more specific example, the full carrier bandwidth could be 80 MHz, the UE could be able to have a maximum carrier bandwidth of 20 MHz, and the base station could accordingly configure a 20 MHz BWP for the UE. As another specific example, the full carrier bandwidth could be 200 MHz, the UE might be able to have a maximum carrier bandwidth of 100 MHz, and the base station could accordingly configure a 100 MHz BWP for the UE.

[0004] Base stations can allocate specific contention-based resource windows (BWPs) for contention-based uplink transmissions. For example, a base station can announce an allocation to a UE by transmitting Radio Resource Control (RRC) protocol messages or broadcasting one or more contention-based BWPs in a System Information Block (SIB). In some cases, a base station can allocate only a certain number of time slots for contention-based access, each time slot comprising a predefined number of Orthogonal Frequency Division Multiplexing (OFDM) symbols. These time slots can have a fixed offset relative to the start of a radio frame of fixed duration and appear at specific periods. Furthermore, the base station can dynamically change certain parameters of the BWP based on the contention level within it.

[0005] To transmit on a contention-based BWP, the UE obtains uplink authorization or permission to transmit at a specific time from the base station. To do this, the UE can perform a random access procedure (RACH), during which the UE first transmits a random access preamble to the base station. This procedure delays transmission and consumes bandwidth and power. Furthermore, this procedure can sometimes result in the UE failing to obtain uplink authorization and thus being unable to obtain access to the time resources used for uplink transmission, because another device has already obtained access to the same time resources. The UE can then re-attempt to obtain access to the BWP at a later time. Summary of the Invention

[0006] When the UE of this disclosure has a small amount of data to transmit to the base station (e.g., less than a predetermined threshold amount), and when the UE is time-aligned with the base station, the UE transmits data on a contention-based BWP without first obtaining or attempting to obtain UL authorization. The UE may be, for example, a sensor or wearable device that reports small amounts of data relatively infrequently.

[0007] The UE can determine whether its time alignment with the base station is still valid based on the amount of time elapsed since it last received a timing advance, for example, based on whether the timeAlignmentTimer is still running. The UE can perform a Listen-Before-Speak (LBT) procedure or another suitable Clear Channel Assessment (CCA) procedure to determine whether time resources are available on a contention-based BWP. Time resources can span one or more OFDM symbols and do not need to be aligned with the boundaries of time slots or subframes.

[0008] In addition to the payload, the UE can also transmit its identifier, modulation and coding scheme (MCS), data redundancy information (e.g., whether this is the first transmission or a retransmission), etc. The base station can then transmit an acknowledgment, for example, a certain number of time slots after the transmission from the UE.

[0009] An example embodiment of these technologies is a method for transmitting data via a contention-based BWP in a UE during an idle state of a protocol for controlling radio resources. The method can be executed by one or more processors and includes: determining that the UE has a time alignment with a base station for uplink transmission to the base station; determining that time resources for uplink transmission are available on the contention-based BWP; and, while the UE is in an idle state, transmitting data within the time resources according to the time alignment.

[0010] Another example embodiment of these technologies is a UE that includes processing hardware and is configured to implement the methods described above. Attached Figure Description

[0011] Figure 1 This is a block diagram of an example wireless communication system in which a UE transmits a small amount of data on a contention-based BWP without first acquiring or requesting uplink authorization.

[0012] Figure 2A This is a message passing diagram of the known four-step RACH process;

[0013] Figure 2B This is a message passing diagram of a known two-step RACH process;

[0014] Figure 3 During that time Figure 1A block diagram of example time resources that a UE can transmit data for;

[0015] Figure 4 This is a flowchart illustrating example methods for transmitting data on a competition-based BWP using different technologies depending on the size of the transmission. Figure 1 Implemented in the UE;

[0016] Figure 5 This is a flowchart of an example method for formatting messages for transmission on a contention-based BWP, which can be... Figure 1 Implemented in the UE; and

[0017] Figure 6 This is a flowchart of an example method for transferring data on a contention-based BWP, which can be... Figure 1 Implemented in the UE. Detailed Implementation

[0018] Figure 1 An example wireless communication system 100 is depicted, in which UE 102 can transmit small amounts of data via a competition-based BWP without first attempting to obtain UL authorization.

[0019] In addition to UE 102, the wireless communication system 100 also includes a base station 104 connected to a core network (CN) 110 via an NG interface or other suitable link. The core network (CN) 110 may be, for example, a fifth-generation core network (5GC). The 5GC may implement multiple components, such as: a User Plane Function (UPF) configured to transmit user plane data packets related to audio calls, video calls, internet traffic, etc.; an Access and Mobility Management (AMF) configured to manage authentication, registration, paging, and other related functions; and a Session Management Function (SMF) configured to manage Protocol Data Unit (PDU) sessions (all not shown to avoid confusion). In this example implementation, base station 104 is a 5G Node B (gNB), but typically base station 104 can be of any suitable type and can support types of Radio Access Technologies (RATs) other than NR. Base station 104 supports cell 120.

[0020] UE 102 can be, for example, a sensor, wearable device, or Internet of Things (IoT) device, configured to transmit data relatively infrequently and in small amounts. More generally, UE 102 can be any device capable of supporting the Radio Access Technology (RAT) of base station 104.

[0021] In operation, UE 102 operating in cell 120 can use time resource 132 to transmit data to base station 104 on contention-based uplink (UL) BWP 130. Because another device, such as UE 108, can attempt to transmit on BWP 130 simultaneously with UE 102, UE 102 can perform a listen-before-speak (LBT) procedure before using time resource 132.

[0022] To support this functionality, UE 102 is equipped with processing hardware 140, which may include one or more general-purpose processors (e.g., a central processing unit (CPU)) and a non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors and / or dedicated processing units. The processing hardware 140 in the example embodiment includes: a contention-based access controller 142 configured to determine when UE 102 can access time resources on a contention-based UL BWP; and a small data transfer (Tx) controller 144 configured to determine when UE 102 should attempt to transmit without obtaining UL authorization.

[0023] Base station 104 is equipped with processing hardware 140, which may further include one or more general-purpose processors and a non-transitory computer-readable memory storing machine-readable instructions executable on the one or more general-purpose processors and / or dedicated processing units. Processing hardware 140 implements a contention-based UL BWP controller 152, configured to determine when UE 102 may transmit small amounts of data on UL BWP 130.

[0024] Base station 104 can dynamically modify UL BWP 130 based on traffic volume. For example, base station 104 can increase the bandwidth of UL BWP 130 when a certain number of uplink transmissions occur on UL BWP 130 during a specific time period. Although Figure 1 The illustration shows a contention-based UL BWP 130, but base station 104 can also support a dedicated BWP for regular UL transmissions. Furthermore, base station 104 can allocate certain time slots for contention-based access within another BWP in some cases, where the remaining time slots conform to another access scheme.

[0025] In order to notify UE 102, UE 108 and other devices in cell 120 of UL BWP130, base station 104 may use, for example, announcements in the System Information Block (SIB) or messages in the Radio Resource Control (RRC) protocol.

[0026] Next, Figure 2AThe diagram illustrates the message passing of a known four-step RACH procedure 200. According to procedure 200, UE 102 transmits a 202 random access preamble (“Msg1”) to base station 104. In response, base station 104 transmits a 204 random access response (RAR or “Msg2”) to UE 102, and UE 102 subsequently transmits a 206 scheduled transport (“Msg3”) to base station 104. Finally, base station 104 transmits a 208 contention resolution (“Msg4”) to UE 102.

[0027] Generally, a two-step RACH process compresses Msg1 and Msg3 into the first step (“MsgA”), and Msg2 and Msg4 into the second step (“MsgB”). Specifically, as... Figure 2B As shown, UE 102 transmits the 222 MsgA preamble on the Physical Random Access Channel (PRACH) and the 226 MsgA data on the Physical Uplink Shared Channel (PUSCH). The MsgA preamble and MsgA data can be separated only by the backoff interval 224, without requiring any messages from base station 104. Base station 104 then responds with MsgB, which includes uplink grant, timing advance, and contention resolution, in response to 228.

[0028] Now for reference Figure 3 Timing diagram 300 illustrates an example schedule, which UE 102 can use to select time resources for transmitting small amounts of data. The bandwidth occupied by BWP 130 is less than the carrier bandwidth of base station 104. Time resources on BWP 130 can have the duration of OFDM symbols, where a certain number of consecutive OFDM symbols define time slots. For example, time slots TS1, TS2, ... TS N Each of these consists of a corresponding sequence of 14 OFDM symbols (symbol #0, symbol #1, ..., symbol #13). Several time slots can define a subframe, and several subframes can form a single frame.

[0029] The small data Tx controller 144 of UE 102 can determine that the size of the UL data is suitable for transmission without requesting uplink authorization. For example, the small data Tx controller 144 can determine that the size of the data 310 to be transmitted in the uplink direction is less than a size threshold T. size (e.g., 10 bytes, 100 bytes, 1KB), and the contention-based access controller 142 can determine that the UE 102 has the necessary time alignment with the base station 104, as referenced below. Figure 4As discussed below, the contention-based access controller 142 can then perform the LBT procedure, and after determining that time resource 312 is available, the small data Tx controller 144 and / or the contention-based access controller 142 can enable UE 102 to transmit small data. As discussed below, the small data Tx controller 144 can also transmit other information along with the data, such as the identifier of UE 102 or the modulation scheme.

[0030] In this example, time resource 312 begins at OFDM symbol #1 and spans six consecutive OFDM symbols (#1, #2, ... #6). In another example, the time resource begins at OFDM symbol #0, aligned with the boundary of slot TS2. Typically, time resources do not need to be aligned with the boundaries of slots or frames and can span any suitable number of OFDM symbols (or other time units).

[0031] Therefore, in order to transmit data 310 during time resource 312, UE 102 does not need to... Figure 2A The process first obtains uplink authorization or according to Figure 2B The process involves attempting to obtain uplink authorization while transmitting data.

[0032] refer to Figure 4 The example method further discusses techniques that UE 102 can implement to transmit data without obtaining uplink authorization. Method 400 can be implemented, for example, in component 142 and / or component 144 as a set of instructions that can be executed by processing hardware 140.

[0033] Method 400 begins at box 402, where UE 102 determines whether the amount of data UE 102 must transmit exceeds a threshold value. If the size is less than the threshold, the process proceeds to box 404; otherwise, the process proceeds to box 430. In box 402, UE 102 can operate in an idle state of the protocol used to control radio resources (e.g., the idle state of the RRC protocol, or RRC_IDLE).

[0034] At box 404, UE 102 determines whether it has time alignment with base station 104. UE 102 may make this determination based on the amount of time that has elapsed since UE 102 last received a timing advance from the base station. As discussed above, for example, UE 102 may receive a timing advance during a random access procedure. As a more specific example, UE 102 may determine whether the timer timeAlignmentTimer specified by 3GPP TS 38.321 is still running. If UE 102 determines that time alignment is still available, the procedure proceeds to box 406. When UE 102 determines that timeAlignmentTimer has expired, or that time alignment is otherwise unavailable, the procedure proceeds to box 430.

[0035] Next, in box 406, UE 102 performs the LBT procedure or another suitable CCA procedure on the competing UL BWP (e.g., UL BWP 130 discussed above). Return to Reference Figure 3 UE 102 can identify time resource 312 as sufficient to transmit a small amount of data during the interval. More specifically, UE 102 can compare the amount of data to be transmitted with the total throughput of time resource 312 under the modulation and coding schemes available to UE 102. UE 102 can detect that ULBWP is in use at the start of the time slot, but determine that time resources not aligned with the time slot boundary are available.

[0036] If UE 102 determines in box 408 that the LBT procedure has successfully completed, and therefore the UL BWP is available for uplink transmission at this time, then the UE performs an unlicensed uplink transmission on the UL BWP in box 410. Otherwise, in box 420, UE 102 increments the counter for keeping track of the LBT attempt and identifies the next potential Tx opportunity. If UE 102 determines in box 422 that the counter has not yet exceeded a predetermined value N (e.g., 3, 4, 5), then the procedure returns to box 406. Otherwise, the procedure proceeds to box 430. Therefore, if UE 102 fails to perform contention-based transmissions a certain number of times consecutively, UE 102 can resume regular, licensed UL transmissions.

[0037] In box 410, UE 102 continues to operate in RRC_IDLE. Therefore, UE 102 does not need to transition to the connected state (RRC_CONNECTED) to perform unlicensed transport on a contention-based BWP. Furthermore, compared to, for example... Figure 2B Unlike transmission 226, UE 102 in frame 410 neither has uplink authorization nor is in the process of obtaining uplink authorization.

[0038] In some implementations, UE 102 may transmit additional information along with the payload at block 410. The additional information may include, for example, the identity of UE 102, such as a Cell Radio Network Temporary Identifier (C-RNTI) or another RNTI. The additional information may also include an indication of the modulation and coding scheme (MCS) used by UE 102 to transmit the payload. UE 102 may select the MCS based on measurements of the strength and / or quality of the DL signal from base station 104, or based on explicit commands from base station 104. Furthermore, the additional information may include data redundancy information to indicate whether UE 102 is transmitting the payload in a first instance, a second instance, or a subsequent instance (in other words, whether this is a retransmission of the payload).

[0039] In some cases, base station 104 specifies the MCS to be used by UE 102 in block 410. Depending on the implementation, base station 104 may advertise the MCS via broadcast in cell 120 or select an MCS specifically for UE 102. In other implementations, UE 102 is configured to use a specific MCS for uplink transmissions on contention-based BWPs.

[0040] According to some implementations, UE 102 specifies a redundancy version along with the MCS as part of additional information. The redundancy version can indicate whether the transmission occurs in the first instance or the second instance.

[0041] In one implementation or scenario, UE 102 uses open-loop power control in block 410 to transmit data on a contention-based ULBWP. In another implementation or scenario, UE 102 receives control parameters from base station 104 for contention-based UL transmission and applies the control parameters at block 410 when transmitting data.

[0042] After UE 102 transmits data in unlicensed mode at box 410, UE 102 can receive a response from base station 104 at box 410. The response can arrive at a predetermined downlink (DL) time slot on the downlink channel.

[0043] When UE 102 determines that the size of the data is greater than or equal to a threshold, UE 102 performs a random access procedure in box 430, such as... Figure 2A Process 200 or Figure 2B The process is as follows: 220. Next, in box 432, UE 102 uses the uplink grant obtained by UE 102 in box 430 to transmit data in the uplink direction.

[0044] Then, UE 102 receives a response from base station 104 in block 434. Base station 104 may transmit the DL response in a predetermined DL time slot after time resource 312. For example, base station 104 may schedule the DL response to occur N time slots after the contention-based UL transmission that occurs in block 410. Base station 104 may specify this timing, for example, using a Layer 3 (L3) message.

[0045] Now for reference Figure 5 Example method 500 for formatting messages for transmission over a contention-based BWP can be implemented in UE 102 or another suitable UE. In box 502, UE 102 selects the MCS (e.g., based on a DL signal from the base station) and specifies the MCS as part of the information accompanying the uplink data. Next, in box 504, UE 102 includes its identity in additional information. In box 506, UE 102 includes a redundant version of the data.

[0046] At box 508, UE 102 selects the power control (parameters) to be transmitted. At box 510, UE 102 formats a message or suitable transmission unit to include a small amount of data along with additional information for transmission in the uplink direction on a contention-based BWP. The data may have a small size, not exceeding a predefined threshold, suitable for transmission on a contention-based BWP to avoid licensing.

[0047] at last, Figure 6 An example method 600 for transmitting data on a contention-based BWP is illustrated, which can also be implemented in UE 102 or another suitable device. In block 602, UE 102 determines that it has a time alignment with the base station for potential uplink transmissions on the contention-based BWP. Next, in block 604, UE 102 can determine that time resources for uplink transmissions are available on the contention-based BWP. For this purpose, UE 102 can use a suitable LBT or another CAA technique. For example, UE 102 can then format messages or transmission units according to method 500 and transmit data (and, in some cases, additional information) on the contention-based BWP in block 606.

[0048] The following description can be applied to the description above.

[0049] User equipment (e.g., UE 102) in which the technologies of this disclosure can be implemented can be any suitable device capable of wireless communication, such as a smartphone, tablet, laptop, mobile game console, point-of-sale (POS) terminal, health monitoring device, drone, camera, streaming dongle or other personal media device, wearable device such as a smartwatch, wireless hotspot, femtocell base station, or broadband router. Furthermore, in some cases, the user equipment can be embedded in electronic systems such as a head unit of a vehicle or an advanced driver assistance system (ADAS). Further still, the user equipment can operate as an Internet of Things (IoT) device or a mobile internet device (MID). Depending on the type, the user equipment may include one or more general-purpose processors, computer-readable storage, a user interface, one or more network interfaces, one or more sensors, etc.

[0050] Some embodiments described in this disclosure include logic or multiple components or modules. A module can be a software module (e.g., code or machine-readable instructions stored on a non-transitory machine-readable medium) or a hardware module. A hardware module is a tangible unit capable of performing a specific operation and can be configured or arranged in a particular manner. A hardware module may contain a permanently configured dedicated circuit system or logic (e.g., as a dedicated processor, such as a field-programmable gate array (FPGA) or application-specific integrated circuit (ASIC), digital signal processor (DSP), etc.) to perform certain operations. A hardware module may also include programmable logic or circuit systems (e.g., as covered in a general-purpose processor or other programmable processor) that are temporarily configured by software to perform certain operations. The decision to implement a hardware module in dedicated and permanently configured circuit systems or in temporarily configured circuit systems (e.g., configured by software) may be driven by cost and time considerations.

[0051] When implemented in software, this technology can be provided as part of an operating system, a library used by multiple applications, or a specific software application. This software can be executed by one or more general-purpose processors or one or more dedicated processors.

[0052] The following list of examples reflects various embodiments explicitly contemplated by this disclosure.

[0053] Example 1. A method for transmitting data via a contention-based BWP during an idle state of a protocol for controlling radio resources is implemented in a UE and executed by processing hardware. The method includes: determining that the UE has a time alignment with a base station for uplink transmission to the base station; determining that time resources for uplink transmission are available on the contention-based BWP; and transmitting data within the time resources according to the time alignment when the UE is in an idle state.

[0054] Example 2. The method of Example 1, wherein the time resource begins at the boundary of an OFDM symbol that does not coincide with the boundary of a time slot consisting of multiple OFDM symbols.

[0055] Example 3. The method of Example 1 or 2, wherein: the transmission occurs within a subframe of a radio frame of fixed duration, the subframe comprising multiple OFDM symbols; the method further comprises not transmitting a random access preamble within the radio frame.

[0056] Example 4. The method of any of the preceding examples further includes selecting time resources for uplink transmission in response to determining that the size of the data is below a threshold size.

[0057] Example 5. The method of any of the preceding examples, wherein determining the availability of time resources includes performing a Listen-Before-Speak (LBT) process.

[0058] Example 6. The method of any of the foregoing examples further includes transmitting the UE's identifier within time resources.

[0059] Example 7. The method of Example 6, where the identifier is a Cell Radio Network Temporary Identifier (C-RNTI).

[0060] Example 8. The method of any of the foregoing examples further includes: transmitting an indication of the modulation and coding scheme (MCS) being used by the UE within the time resources.

[0061] Example 9. The method of any one of Examples 1 to 8 further includes: selecting the MCS by processing hardware based on downlink (DL) signal measurements.

[0062] Example 10. The method according to any of the foregoing examples further includes: receiving an indication of an MCS to be used in a contention-based BWP; wherein the transmission conforms to the MCS.

[0063] Example 11. The method of any of the preceding examples further includes: an indication of transmitting a redundant version of the data within a time resource.

[0064] Example 12. The method of any of the foregoing examples further includes: receiving power control parameters from a base station by processing hardware; wherein the transmission includes applying the power control parameters.

[0065] Example 13. The method of any of Examples 1 to 11, wherein the transmission includes the application of open-loop power control.

[0066] Example 14. A method of any of the preceding examples, wherein determining that the UE has time alignment with the base station is based on the amount of time elapsed since the UE last received a timing advance from the base station.

[0067] Example 15. A method of any of the preceding examples, wherein: transmission occurs in a first instance, the method further comprising, in a second instance: when the UE has time alignment with the base station, the processing hardware identifies a second resource on a contention-based BWP for transmitting second data, and in response to determining that the second resource is unavailable, performing a process for obtaining an uplink grant for transmitting the second data on the contention-based BWP.

[0068] Example 16. The method of Example 15, wherein determining that the second resource is unavailable includes causing the LBT process to fail N times, where N>=1.

[0069] Example 17. The method of any of the preceding examples further includes: receiving a response to data from the base station by processing hardware.

[0070] Example 18. The method of Example 17 includes receiving a response in a time slot that is offset by a fixed interval from a time slot including time resources.

[0071] Example 19. The method of Example 18 further includes: receiving a fixed interval from a base station.

[0072] Example 20. A UE, including processing hardware and configured to implement any of the foregoing examples.

Claims

1. A wireless communication method performed by a user equipment (UE), the method comprising: Determine whether the amount of uplink UL data transmitted to the base station is below a threshold value; as well as In response to determining that the amount of UL data is below the threshold value: Based on the amount of time elapsed since the UE last received a timing advance from the base station, it is determined that the UE has time alignment with the base station for UL transmission to the base station; The idle channel assessment (CCA) process is performed based on the determination that the time resources for the UL transmission are available on the contention-based bandwidth portion (BWP). as well as While the UE is in an idle state, the UL data is transmitted within a subframe of a radio frame without transmitting the random access preamble within the radio frame, the subframe being aligned with the time resource according to the time.

2. The method according to claim 1, wherein: The time resources begin at the first boundary of an OFDM symbol, wherein the first boundary does not coincide with the second boundary of a time slot consisting of multiple OFDM symbols.

3. The method according to claim 1, wherein: The radio frame has a fixed duration, and the subframe includes multiple OFDM symbols.

4. The method according to claim 1, further comprising: The time resource is selected for the UL transmission in response to determining that the size of the data is below a threshold size.

5. The method according to claim 1, wherein, Determining the availability of the time resources includes: Perform the Listen Before You Speak (LBT) process.

6. The method of claim 1, further comprising: Receive instructions on the MCS to be used in the competition-based BWP; The transmission conforms to the MCS.

7. The method according to claim 1, wherein: The transmission occurs in the first instance. In the second example, the method further includes: When the UE has time alignment with the base station, it identifies the second resource on the contention-based BWP used for transmitting the second UL data, and In response to determining that the second resource is unavailable, a process for obtaining UL authorization for transmitting the second UL data is performed.

8. The method according to claim 7, wherein, Determining that the second resource is unavailable includes causing the LBT process to fail. N Second-rate, N >=1.

9. The method of claim 1, further comprising: Receive a response to the UL data from the base station.

10. The method of claim 9, wherein the reception of the response occurs in a time slot offset by a fixed interval from the time slot including the time resource.

11. The method of claim 10, further comprising: Receive the instruction for the fixed interval from the base station.

12. The method according to claim 1, wherein: The contention-based BWP is one of several contention-based BWPs supported by the base station for regular UL transmission.

13. The method according to any one of claims 1 to 11, wherein: The competition-based BWP is the first competition-based BWP; as well as The second contention-based BWP includes time slots allocated by the base station for contention-based access.

14. The method according to claim 13, wherein, The first contention-based BWP and the second contention-based BWP have different access schemes.

15. A user equipment (UE) including processing hardware and configured to implement the method of any one of claims 1-14.

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