WO2022205427A1

WO2022205427A1 - Validation of timing advance in wireless communication

Info

Publication number: WO2022205427A1
Application number: PCT/CN2021/085320
Authority: WO
Inventors: Li Zhang; Juan Liu
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2021-04-02
Filing date: 2021-04-02
Publication date: 2022-10-06
Anticipated expiration: 2023-10-02
Also published as: CN116868637A

Abstract

Systems, apparatus and method of wireless communication are provided. A method for wireless communication includes performing, by a wireless device, a determination about whether a timing advance (TA) validation condition is met, and selectively performing a small data transmission responsive to a result of the determination. A reference signal received power (RSRP) measurement is performed for TA validation.

Description

VALIDATION OF TIMING ADVANCE IN WIRELESS COMMUNICATION

TECHNICAL FIELD

This document is directed generally to wireless communications.

BACKGROUND

Mobile communication technologies are moving the world toward an increasingly connected and networked society. The rapid growth of mobile communications and advances in technology have led to greater demand for capacity and connectivity. Other aspects, such as energy consumption, device cost, spectral efficiency, and latency are also important to meeting the needs of various communication scenarios. Various techniques, including new ways to provide higher quality of service, longer battery life, and improved performance are being discussed.

SUMMARY

This patent document describes, among other things, techniques for timing advance (TA) validation in wireless networks.

In one example aspect, a method of wireless communication is disclosed. The method includes performing, by a wireless device, a determination about whether a timing advance (TA) validation condition is met, and selectively performing a small data transmission responsive to a result of the determination.

In another example aspect, another method of wireless communication is disclosed. The method includes transmitting, from a network device to a wireless device, a message identifying a set of beams that the wireless device is to use for a timing advance (TA) validation procedure.

In yet another example embodiment of the disclosed technology, the above-described methods are embodied in the form of processor-executable code and stored in a computer-readable program medium.

In yet another example embodiment of the disclosed technology, a device that is configured or operable to perform the above-described methods is disclosed.

The above and other aspects and their implementations are described in greater detail in the drawings, the descriptions, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a wireless communication system.

FIG. 2 is a flowchart of an example method of validating Timing Advance (TA) .

FIG. 3 shows an example configuration of a wireless network.

FIG. 4 is a flowchart for an example method of wireless communication.

FIG. 5 is a flowchart for an example method of wireless communication.

FIG. 6 is a block diagram representation of a portion of a radio station in accordance with one or more embodiments of the present technology can be applied.

DETAILED DESCRIPTION

The present document uses examples from the 3GPP New Radio (NR) network architecture and 5G protocol only to facilitate understanding and the disclosed techniques and embodiments may be practiced in other wireless systems that use different communication protocols than the 3GPP protocols.

Some applications of wireless communications include devices or appliances that are configured to perform wireless communication but may not be continuously powered. Some examples include battery operated devices such as power meters, product ID tags, and so on. These devices may go into long sleep modes and awake at certain infrequent times to communicate with the network. For example, some devices such as utility meters may wake up once every day or once every week or month to communicate with a network-side server.

Future wireless standards are planning to support such use cases by defining protocols for communication that provide transmission opportunities to wireless devices using relatively smaller bandwidths (e.g., compared to bandwidths used by smartphones) , and for infrequent communication of small amount of data such as a few kilobytes at a time.

In the upcoming 5G standard, a communication protocol, commonly called narrowband internet-of-things (NB-IoT) , has been provided to address such scenarios. This protocol may be used by such small data transmission embodiments. One challenge faced by such a use case is that, from one use of a wireless device to a next use, the wireless channel between the wireless device and the network may have changed significantly unknown to the wireless device and the network. One reason being that, unlike devices that are powered continuously (e.g., smartphones) and that continuously exchange messages with the network to track changes to the wireless channel, the wireless channel may change significantly due to mobility of the wireless device during the time the wireless device is disconnected from the network. For example, the distance between a wireless device and a network device, which affects the transmission delay or timing delay between the wireless device and the network device, may have changed significantly.

In NB-IoT pre-configured uplink resources (PUR) , considering TA timer duration does not reflect the UE’s mobility, therefore the UE may become misaligned before the TA timer expires. Also, the UE may be still time aligned when the TA timer expires. Therefore, the TA validation was extended to judge the variation of the serving cell reference signal received power (RSRP) . The detailed description in TS 36.331 specification is as below.

Table 1

Before the UE proceeds to perform a PUR transmission, the current measured serving cell RSRP as neither increased above the increaseThresh nor has decreased below the decreaseThresh compared to the previous serving cell RSRP should be ensured if pur-RSRP-ChangeThreshold is configured.

For small data transmission, configured grant (CG) based small data transfer (SDT) is being discussed in the 3GPP. Similar to PUR, the variation of RSRP should also be considered before transmission due to the UE mobility. However, in New Radio (NR) , the feature of multi-beam is introduced. In such a scenario, it may not be sufficient to use the serving cell RSRP. This document provides techniques that may be used by embodiments operating in a multi-beam scenario to perform TA validation.

Brief discussion

For a multi-beam scenario, a direct way is that beam specific RSRP such as Synchronization Signal (SS) RSRP may be used to judge TA validation. In other words, in the description in Table 1 above, the serving cell RSRP may be replaced by SS-RSRP. However, one drawback of this strategy is that beam may have changed due to the UE mobility. Hence, in the following, some approaches are given regarding on how to calculate RSRP variation based on beam specific RSRP.

Approach 1: Before performing a small data transmission, if RSRP judgement threshold is configured, the UE will calculate RSRP variation between the RSRP of the current beam and the RSRP of the beam used by the UE when last TA is valid. If the RSRP variation has neither increased above the threshold1 nor has decreased below the threshold2, and if TA timer is running or TA timer is not configured, TA is considered valid.

Approach 2: Before small data transmission, if RSRP judgement threshold is configured, the UE will calculate RSRP variation of each beam within a certain beam subset. The beam subset may be configured by network or selected by the UE based on a measurement result. If there is at least a beam which RSRP variation has neither increased above the threshold1 nor has decreased below the threshold2, and if TA timer is running or TA timer is not configured, TA is considered valid.

Approach 3: before small data transmission, if RSRP judgement threshold is configured, the UE derives a linear power scale average value RSRP1 based on RSRP value of a certain beam subset and calculates RSRP variation between RSRP1 and the current linear power scale average value RSRP2 which is derived based on the beam subset when the last TA is valid. The beam subset may be configured by network or selected by the UE based on measurement result. If the RSRP variation has neither increased above the threshold1 nor has decreased below the threshold2, and if TA timer is running or TA timer is not configured, TA may be considered valid.

Example Embodiments

Embodiment 1

Small data transmission based on a configured grant is mainly used for stationary or low mobility UE. In some scenarios, RSRP judgement for TA validation is not necessary. Hence RSRP judgement may be defined as optional UE capability. When the UE supports this capability and the parameters related to RSRP judgement are configured, the UE needs to judge whether RSRP variation has not decreased and/or increased by more than threshold1 and/or threshold2.

A possible example is as below:

UE capability:

ta-RSRPjudgement ENUMERATED {supported} OPTIONAL,

Threshold:

Embodiment 2

When small data transmission is triggered, the UE calculates RSRP variation between RSRP of the current serving beam and the RSRP of the beam used by the UE when last TA is valid. If the RSRP variation has neither increased above the threshold1 nor has decreased below the threshold2, and if TA timer is running or TA timer is not configured, TA is considered valid.

FIG. 3 shows an example of a wireless system in which multiple beams may be used during the wireless communication. Here, the wireless device UE1 may communication with a network device, shown as a base station 302, using one or more of beams 1 to 5 at different time. As further described in the present document, one or more beam measurements may be used for validating TA in such a scenario.

For example, referring to FIG. 3, In T1, TA is updated and beam 2 is as the serving beam. When small data transmission is triggered in T2, beam 4 is as the current serving beam due to the UE mobility as in figure 1 below. The UE needs to judge whether RSRP variation between beam 2 and beam 4 if threshold is configured. If RSRP variation has not decreased by more than threshold 1 and increased by more than threshold 2 if threshold2 is configured, and if TA timer is running or TA timer is not configured, the UE assumes that TA is valid. Then small data transmission may be performed in the configured grant resource.

Regarding beam change, a possible judgement is that once the best beam has changed, the current best beam may be used as a new serving beam. Of course, in the disclosed embodiments, the judgement regarding which beam to use may not just be based on the beam with highest RSRP, and other possible beam selection techniques may be used.

Base station functionalities

In some embodiments, a message may include an information element, called SDT-RSRP-ChangeThreshold, including increaseThresh and decreaseThresh and TA timer may be configured to UE. In some embodiments, this configuration may be performed via an RRC release message or other RRC message.

UE side functionalities

In some embodiments, UE will consider the timing alignment value for transmission using configured grant to be valid when all of the following conditions are fulfilled:

1> if cg-sdt-TimeAlignmentTimer is configured:

2> cg-sdt-TimeAlignmentTimer is running as confirmed by lower layers;

1> if sdt-RSRP-ChangeThreshold is configured:

2> since the last TA validation, SS-RSRP has not increased by more than increaseThresh; and

2> since the last TA validation, SS-RSRP has not decreased by more than decreaseThresh.

In such embodiments, if any of the above condition is not fulfilled, then the UE may consider that the timing alignment is incorrect and may refrain from a small data transmission using the configured grant resource.

Embodiment 3

When small data transmission is triggered, the UE will calculate RSRP variation between the current RSRP and the RSRP since the last TA validation for each beam within a certain beam subset. The beam subset may be configured by network or selected by the UE based on measurement result. If there is at least a beam which RSRP variation has not decreased by more than threshold 1 and increased by more than threshold 2, and if TA timer is running or TA timer is not configured, the UE assumes that TA is valid. Then small data transmission may be performed in the configured grant resource.

Embodiment 4 (Approach 3)

When small data transmission is triggered, the UE derives a linear power scale average value RSRP 1 based on RSRP value of a certain beam subset and calculates RSRP variation between RSRP1 and the current linear power scale average value RSRP 2 which is derived based on the beam subset when the last TA is valid. The beam subset may be configured by network or selected by the UE based on measurement result. In some embodiments, the values RSRP 1 and RSRP 2 may be determined as a different function of the RSRPs of the beam subset. Some example functions may include weighting the RSRP relative to “last used” time of the beam, and so on.

If the RSRP variation has neither increased above the threshold1 nor has decreased below the threshold2, and if TA timer is running or TA timer is not configured, TA is considered valid. In case that the TA is valid, a small data transmission using the configured grant may be performed.

FIG. 1 shows an example of a wireless communication system (e.g., an LTE, 5G New Radio (NR) cellular network) that includes a radio access node 120 and one or more wireless devices such as user equipment (UE) 111, 112 and 113. In some embodiments, the downlink transmissions (141, 142, 143) include a control plane message that comprises a processing order for processing the plurality of user plane functions. This may be followed by uplink transmissions (131, 132, 133) based on the processing order received by the UEs. Similarly, the user plane functions can be processed by UEs for downlink transmissions based on the processing order received. The UE may be, for example, a smartphone, a tablet, a mobile computer, a machine to machine (M2M) device, a terminal, a mobile device, an Internet of Things (IoT) device, and so on.

FIG. 2 shows an example flowchart of a TA validation procedure. At the top, TA may be assumed to be valid. A determination may be made regarding whether TA timer is configured. If the TA timer is not configured, then TA validation based on TA timer is not performed. If the TA timer is configured, then a check is made regarding whether TA is running. In case that TA is running, then TA is assumed to be valid if threshold is not configured, otherwise, another condition should be checked. If TA is not running, then TA is assumed to be invalid.

Further, a check is made regarding whether RSRP threshold has been configured for the wireless device. If RSRP threshold has not been configured, then TA validation judgement is not performed. If RSRP threshold has been configured, then a check is made regarding whether a RSRP variation calculation meets the threshold comparisons described here. If the answer is that the threshold comparison is satisfied (e.g., using threshold1 and threshold2 as described above) , then TA is considered valid, otherwise TA is considered invalid.

Some preferred embodiments may implement the following solutions variously incorporate approaches 1 to 3, described in the present document.

1. A method for wireless communication (e.g., method 400 shown in FIG. 4) , comprising: performing (402) , by a wireless device, a determination about whether a timing advance (TA) validation condition is met; and selectively performing (404) a small data transmission responsive to a result of the determination. The small data transmission is selectively performed in that if TA cannot be validated, the wireless device will refrain from making a small data transmission using the pre-configured resource. In such cases, the wireless device may use alternate methods such as performing a data transmission on a random access channel or may request that the network device may initiate a TA calibration procedure.

2. The method of solution 1, wherein the TA validation condition comprises that TA is configured and a TA timer is running.

3. The method of

solution

1 or 2, wherein the determination of the TA validation condition comprises a reference signal received power (RSRP) variation comparison between a first beam at a current time and a second beam at a past time.

4. The method of solution 3, wherein the small data transmission is performed in cases that the RSRP variation comparison has not increased above a first threshold and/or decreased below a second threshold.

5. The method of solutions 3-4, wherein the first beam is a current serving beam, the second beam is a beam used for a last TA validation and the past time is a time at which the last TA validation was performed.

6. The method of solutions 3-4, wherein the first beam is a current serving beam, the second beam is a beam used after a last TA validation and the past time is a time after the last TA validation was performed.

7. The method of solutions 3-4, wherein the first beam is a current serving beam, the second beam is the current serving beam and the past time is a time at which use of current beam was commenced and an RSRP measurement was performed.

8. The method of

solution

1 or 2, wherein the determination of the TA validation condition comprises a reference signal received power (RSRP) variation comparison between a first RSRP value based on a first set of beams at a current time and a second RSRP value based on a second set of beams at a past time.

9. The method of solution 1, wherein the past time corresponds to a time at which a previous RSRP validation was performed.

10. The method of any of solutions 1-2, wherein the comparison comprises comparing the RSRP variation for each beam in the first set of beams.

11. The method of solution 8, wherein the comparison comprises comparing the first RSRP value and the second RSRP value.

12. The method of solution 11 wherein the first value is a linear power scale average value of RSRPs for beams in the first set of beams and the second value is a linear power scale average value of RSRPs in the second set of beams.

13. The method of solution 12, wherein the first set of beams is same as the second set of beams.

14. The method of any of solutions 8-13, wherein the first set of beams and the second set of beams are determined by the wireless device.

15. The method of any of solutions 8-13, wherein the first set of beams and the second set of beams are indicated to the wireless device by a network device.

16. A method of wireless communication (e.g., method 500 depicted in FIG. 5) , comprising: transmitting (502) , from a network device to a wireless device, a message identifying a set of beams that the wireless device is to use for a timing advance (TA) validation procedure. In various embodiments, different techniques may be used to identify the set of beams. For example, in some embodiments, the set of beams may include all beams between the wireless device and the network device where RSRP is above a threshold. In some embodiments, beams that were previously used for communication by the wireless device and meet the RSRP criteria may be used. Alternatively, in some embodiments, previously used beams may be excluded and any other beams that meet the RSRP criteria may be included in the subset.

17. The method of solution 16, wherein the network device further transmits a first threshold value to the wireless device, wherein the first threshold value is for a comparison of a maximum variation in reference signal received power (RSRP) value during the TA validation procedure.

18. The method of solution 15-16, wherein the network device further transmits a second threshold value to the wireless device, wherein the second threshold value is for a minimum comparison of a variation in reference signal received power (RSRP) value during the TA validation procedure

19. The method of any of solutions 16-18, wherein the message is transmitted in a radio resource control message.

20. An apparatus for wireless communication, comprising a memory and a processor, wherein the processor reads code from the memory and implements a method recited in any of solutions 1 to 19.

21. A computer readable program storage medium having code stored thereon, the code, when executed by a processor, causing the processor to implement a method recited in any of solutions 1 to 19.

In the above-listed solutions, while RSRP is used as an example of a measurement technique that is used for validation of TA and for selection of beam (s) to be used for communication, other channel quality determination criteria may also be used, e.g., signal to noise ratio estimates, bit error rate, and so on.

FIG. 6 is a block diagram representation of a portion of a radio station in accordance with one or more embodiments of the present technology can be applied. A radio station 605 such as a base station or a network device or a wireless device (or UE) can include processor electronics 610 such as a microprocessor that implements one or more of the wireless techniques presented in this document. The radio station 605 can include transceiver electronics 615 to send and/or receive wireless signals over one or more communication interfaces such as antenna 620. The radio station 605 can include other communication interfaces for transmitting and receiving data. Radio station 605 can include one or more memories (not explicitly shown) configured to store information such as data and/or instructions. In some implementations, the processor electronics 610 can include at least a portion of the transceiver electronics 615. In some embodiments, at least some of the disclosed techniques, modules or functions are implemented using the radio station 605.

Some of the embodiments described herein are described in the general context of methods or processes, which may be implemented in one embodiment by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. A computer-readable medium may include removable and non-removable storage devices including, but not limited to, Read Only Memory (ROM) , Random Access Memory (RAM) , compact discs (CDs) , digital versatile discs (DVD) , etc. Therefore, the computer-readable media can include a non-transitory storage media. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-or processor-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

Some of the disclosed embodiments can be implemented as devices or modules using hardware circuits, software, or combinations thereof. For example, a hardware circuit implementation can include discrete analog and/or digital components that are, for example, integrated as part of a printed circuit board. Alternatively, or additionally, the disclosed components or modules can be implemented as an Application Specific Integrated Circuit (ASIC) and/or as a Field Programmable Gate Array (FPGA) device. Some implementations may additionally or alternatively include a digital signal processor (DSP) that is a specialized microprocessor with an architecture optimized for the operational needs of digital signal processing associated with the disclosed functionalities of this application. Similarly, the various components or sub-components within each module may be implemented in software, hardware or firmware. The connectivity between the modules and/or components within the modules may be provided using any one of the connectivity methods and media that is known in the art, including, but not limited to, communications over the Internet, wired, or wireless networks using the appropriate protocols.

While this document contains many specifics, these should not be construed as limitations on the scope of an invention that is claimed or of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or a variation of a sub-combination. Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results.

Only a few implementations and examples are described and other implementations, enhancements and variations can be made based on what is described and illustrated in this disclosure.

Claims

A method for wireless communication, comprising:

performing, by a wireless device, a determination about whether a timing advance (TA) validation condition is met; and

selectively performing a small data transmission responsive to a result of the determination.
The method of claim 1, wherein the TA validation condition comprises that TA is configured and a TA timer is running.
The method of claim 1 or 2, wherein the determination of the TA validation condition comprises a reference signal received power (RSRP) variation comparison between a first beam at a current time and a second beam at a past time.
The method of claim 3, wherein the small data transmission is performed in cases that the RSRP variation comparison has not increased above a first threshold and/or decreased below a second threshold.
The method of claims 3-4, wherein the first beam is a current serving beam, the second beam is a beam used for a last TA validation and the past time is a time at which the last TA validation was performed.
The method of claims 3-4, wherein the first beam is a current serving beam, the second beam is a beam used after a last TA validation and the past time is a time after the last TA validation was performed.
The method of claims 3-4, wherein the first beam is a current serving beam, the second beam is the current serving beam and the past time is a time at which use of current beam was commenced and an RSRP measurement was performed.
The method of claim 1 or 2, wherein the determination of the TA validation condition comprises a reference signal received power (RSRP) variation comparison between a first RSRP value based on a first set of beams at a current time and a second RSRP value based on a second set of beams at a past time.
The method of claim 1, wherein the past time corresponds to a time at which a previous RSRP validation was performed.
The method of any of claims 1-2, wherein the comparison comprises comparing the RSRP variation for each beam in the first set of beams.
The method of claim 8, wherein the comparison comprises comparing the first RSRP value and the second RSRP value.
The method of claim 11 wherein the first value is a linear power scale average value of RSRPs for beams in the first set of beams and the second value is a linear power scale average value of RSRPs in the second set of beams.
The method of claim 12, wherein the first set of beams is same as the second set of beams.
The method of any of claims 8-13, wherein the first set of beams and the second set of beams are determined by the wireless device.
The method of any of claims 8-13, wherein the first set of beams and the second set of beams are indicated to the wireless device by a network device.
A method of wireless communication, comprising:

transmitting, from a network device to a wireless device, a message identifying a set of beams that the wireless device is to use for a timing advance (TA) validation procedure.
The method of claim 16, wherein the network device further transmits a first threshold value to the wireless device, wherein the first threshold value is for a comparison of a maximum variation in reference signal received power (RSRP) value during the TA validation procedure.
The method of claim 15-16, wherein the network device further transmits a second threshold value to the wireless device, wherein the second threshold value is for a minimum comparison of a variation in reference signal received power (RSRP) value during the TA validation procedure.
The method of any of claims 16-18, wherein the message is transmitted in a radio resource control message.
An apparatus for wireless communication, comprising a memory and a processor, wherein the processor reads code from the memory and implements a method recited in any of claims 1 to 19.
A computer readable program storage medium having code stored thereon, the code, when executed by a processor, causing the processor to implement a method recited in any of claims 1 to 19.