阅读说明：本技术 用于电信系统中的随机接入过程的方法和装置 (Method and arrangement for random access procedure in a telecommunication system ) 是由 S·图尔蒂南 T·科斯克拉 吴春丽 S·阿科拉 于 2018-09-20 设计创作，主要内容包括：本公开的实施例提供了用于功率控制的方法、装置和计算机程序。根据一个或多个实施例,一种在终端设备处实现的方法包括：在随机接入过程中针对随机接入前导码传输选择波束,其中所选择的波束不同于针对先前的随机接入前导码传输而被选择的波束；确定所选择的波束对先前选择的波束是否具有准共址假定,或者所选择的波束和先前选择的波束两者是否对同一波束具有准共址假定；以及基于该确定来决定是否提升随机接入前导码传输的功率。(Embodiments of the present disclosure provide methods, apparatus and computer programs for power control. In accordance with one or more embodiments, a method implemented at a terminal device comprises: selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission; determining whether the selected beam has a quasi-co-location assumption for a previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam; and deciding whether to boost the power of the random access preamble transmission based on the determination.)

1. A method implemented at a terminal device, comprising:

selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission;

determining whether the selected beam has a quasi-co-location assumption for a previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam; and

deciding whether to boost the power of the random access preamble transmission based on the determination.

2. The method of claim 1, wherein deciding whether to boost the power of the random access preamble transmission based on the determination further comprises:

in response to determining that the selected beam has a quasi-co-location assumption for a previously selected beam or that both the selected beam and a previously selected beam have quasi-co-location assumptions for the same beam, deciding to boost the power of the random access preamble transmission.

3. The method of claim 2, further comprising:

performing a power boost for the random access preamble transmission by incrementing the power for the random access preamble transmission by a predetermined power boost step size.

4. The method of claim 3, wherein:

the predetermined power ramping stepsize is achieved by incrementing a preamble power ramping counter for the random access preamble transmission by 1.

5. The method of claim 2, further comprising:

performing a power boost for the random access preamble transmission by incrementing the power for the random access preamble transmission by a portion of a predetermined power boost step size.

6. The method of claim 1, wherein the quasi co-location assumption is established on a condition that two beams share one or more same attributes, the one or more same attributes being selected from the group consisting of:

the delay spread is such that the delay spread,

the average delay is calculated by averaging the delay,

the spread of the doppler is then detected,

the doppler shift is a frequency shift of the doppler,

spatial receiver parameters.

7. The method of claim 1, wherein selecting a beam for random access preamble transmission in a random access procedure comprises:

preferentially selecting a beam having a quasi co-location assumption for the previously selected beam or for the same beam as the previously selected beam.

8. The method of any one of claims 1 to 7, wherein:

the selected beam is a synchronization signal block or a beam of a channel state information reference signal, and

the previously selected beam is a beam of a synchronization signal block or a channel state information reference signal.

9. The method of claim 8, wherein performing power boosting for the random access preamble transmission further comprises:

performing power boosting for the random access preamble transmission only when no random access resources are associated with the selected beam of channel state information reference signals.

10. A terminal device, comprising:

at least one processor; and

at least one memory including computer program code;

the at least one memory and the computer program code configured to, with the at least one processor, cause the terminal device to:

selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission;

determining whether the selected beam has a quasi-co-location assumption for a previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam;

deciding whether to boost the power of the random access preamble transmission based on the determination.

11. The terminal device of claim 10, wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the terminal device to decide whether to boost the power of the random access preamble transmission based on the determination comprises:

in response to determining that the selected beam has a quasi-co-location assumption for a previously selected beam or that both the selected beam and a previously selected beam have quasi-co-location assumptions for the same beam, deciding to boost the power of the random access preamble transmission.

12. The terminal device of claim 11, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal device to further:

performing a power boost for the random access preamble transmission by incrementing the power for the random access preamble transmission by a predetermined power boost step size.

13. The terminal device of claim 12, wherein:

the predetermined power ramping stepsize is achieved by incrementing a preamble power ramping counter for the random access preamble transmission by 1.

14. The terminal device of claim 11, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the terminal device to further:

performing a power boost for the random access preamble transmission by incrementing the power for the random access preamble transmission by a portion of a predetermined power boost step size.

15. The terminal device of claim 10, wherein the quasi co-location assumption is established on a condition that two beams share one or more same attributes, the one or more same attributes being selected from the group consisting of:

the delay spread is such that the delay spread,

the average delay is calculated by averaging the delay,

the spread of the doppler is then detected,

the doppler shift is a frequency shift of the doppler,

spatial receiver parameters.

16. The terminal device of claim 10, wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the terminal device to select a beam for random access preamble transmission in a random access procedure comprises:

preferentially selecting a beam having a quasi co-location assumption for the previously selected beam or for the same beam as the previously selected beam.

17. The terminal device of any of claims 10 to 16, wherein:

the selected beam is a synchronization signal block or a beam of a channel state information reference signal, and

the previously selected beam is a beam of a synchronization signal block or a channel state information reference signal.

18. The method of claim 17, wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the terminal device to perform power boosting for the random access preamble transmission further comprises:

performing power boosting for the random access preamble transmission only when no random access resources are associated with the selected beam of channel state information reference signals.

19. An apparatus, comprising:

means for selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission;

means for determining whether the selected beam has a quasi-co-location assumption for a previously selected beam or whether both the selected beam and a previously selected beam have quasi-co-location assumptions for the same beam; and

means for deciding whether to boost the power of the random access preamble transmission based on the determination.

20. The apparatus of claim 19, wherein the means comprises:

at least one processor; and

at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause execution of the apparatus.

21. A computer-readable storage medium having stored thereon a computer program which, when executed by a processor, causes the processor to:

selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission;

determining whether the selected beam has a quasi-co-location assumption for a previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam; and

deciding whether to boost the power of the random access preamble transmission based on the determination.

22. A computer-readable medium, on which a computer program is stored which, when executed by at least one processor of an apparatus, causes the apparatus to perform the method according to any one of claims 1 to 9.

Technical Field

The non-limiting and example embodiments of the present disclosure relate generally to the field of wireless communication technology and, in particular, relate to a method, apparatus and computer program for random access procedures in a wireless communication network.

Background

This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements in this section should be read in this light and not as admissions of what is present in the prior art or what is not present in the prior art.

In cellular systems, a terminal device, such as a User Equipment (UE), is allowed to initially request connection setup with a network device, such as an enhanced nodeb (enodeb) or a gNB. Such a procedure is commonly referred to as "random access".

In the random access procedure, the UE needs to send a random access preamble on a Physical Random Access Channel (PRACH) to its serving network device in a first step (message 1). Upon reception in the network device, the preamble should therefore be detected so that the network device can perform the following steps in the random access procedure.

In 5G communication systems, such as NR, PRACH preambles and/or PRACH occasions may be associated with Synchronization Signal Blocks (SSBs) and/or channel state information reference signals (CSI-RSs). The association provides a means for the UE to signal the preferred downlink beam (e.g., in initial access, handover, or beam failure recovery) and a means for the network device, such as the gNB, to set up the appropriate receive beam. A beam is generally considered to correspond to a Reference Signal (RS) and may be, for example, one of an SSB or CSI-RS. Fig. 1 schematically shows a time-frequency structure 100 of an SSB. As shown in fig. 1, the SSB includes a Physical Broadcast Channel (PBCH)110, a Primary Synchronization Signal (PSS)120, and a Secondary Synchronization Signal (SSS) 130. Each of the PSS 120 and the SSS 130 occupies 1 Orthogonal Frequency Division Multiplexing (OFDM) symbol and 127 subcarriers. The PBCH 110 spans 3 OFDM symbols and 240 subcarriers, where an unused portion in the frequency domain is reserved for SSS 130 on one symbol, as shown in fig. 1. The period of the SSB may be configured by the network.

The common RACH configuration for the beam in the target cell is associated only with the SSB(s). On the other hand, the network may have dedicated RACH configurations associated with the SSB(s) and/or dedicated RACH configurations associated with the CSI-RS(s) within the cell. According to 3GPP TS 38.300 release 15, the target gNB can only include one of the following RACH configurations in the handover command to enable the UE to access the target cell:

i) a common RACH configuration;

ii) common RACH configuration + dedicated RACH configuration associated with SSB(s);

iii) common RACH configuration + dedicated RACH configuration associated with CSI-RS(s).

Disclosure of Invention

Since different beams of SSB(s) or CSI-RS(s) may be associated with the PRACH preamble, there is a need to further define the behavior of the UE after downlink beam changes during the random access procedure.

To address at least a portion of the above issues, methods, apparatuses, and computer programs are provided in the present disclosure. It is to be understood that embodiments of the present disclosure are not limited to a 5G scenario, but may be more broadly applied to any application scenario where similar issues exist.

Various embodiments of the present disclosure are generally directed to methods, apparatuses, and computer programs for power control. Other features and advantages of embodiments of the present disclosure will also be understood from the following description of specific embodiments, when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of embodiments of the disclosure.

According to a first aspect of the present disclosure, a method implemented at a terminal device is provided. The method comprises the following steps: selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission; determining whether the selected beam has a quasi-co-location assumption for a previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam; and deciding whether to boost (ramp up) the power of the random access preamble transmission based on the determination.

According to a second aspect of the present disclosure, a terminal device is provided. The terminal device includes at least one processor; and at least one memory including computer program code. The at least one memory and the computer program code configured to, with the at least one processor, cause the terminal device to: selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission; determining whether the selected beam has a quasi-co-location assumption for a previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam; and deciding whether to boost the power of the random access preamble transmission based on the determination.

According to a third aspect of the present disclosure, an apparatus is provided. The apparatus comprises means for selecting a beam for a random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission; means for determining whether the selected beam has a quasi-co-location assumption for a previously selected beam or whether both the selected beam and a previously selected beam have quasi-co-location assumptions for the same beam; and means for deciding whether to boost the power of the random access preamble transmission based on the determination.

According to a fourth aspect of the present disclosure, there is provided a computer readable storage medium having a computer program stored thereon. The computer program, when executed by a processor, causes the processor to: selecting a beam for random access preamble transmission in a random access procedure, wherein the selected beam is different from a beam selected for a previous random access preamble transmission; determining whether the selected beam has a quasi-co-location assumption for a previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam; and deciding whether to boost the power of the random access preamble transmission based on the determination.

According to a fifth aspect of the present disclosure, there is provided a computer-readable medium comprising instructions which, when executed on one or more processors, cause the one or more processors to perform the method of an embodiment of the first aspect of the present disclosure.

Drawings

The above and other aspects, features and benefits of various embodiments of the present disclosure will become more fully apparent from the following detailed description, by way of example, with reference to the accompanying drawings, wherein like reference numerals or letters are used to designate similar or equivalent elements. The accompanying drawings are illustrated to facilitate a better understanding of embodiments of the disclosure and are not necessarily drawn to scale, wherein:

fig. 1 shows a time-frequency structure of a synchronization signal block;

fig. 2 shows a flow diagram of a method 200 implemented at a terminal device in accordance with one or more embodiments of the present disclosure;

fig. 3 shows a schematic block diagram of an apparatus 300 implemented as/in a terminal device in accordance with one or more embodiments of the present disclosure; and

fig. 4 shows a simplified block diagram of an apparatus 410 that may be implemented as/in a terminal device and an apparatus 420 that may be implemented as/in a network device.

Detailed Description

Hereinafter, the principle and spirit of the present disclosure will be described with reference to illustrative embodiments. It is to be understood that all such embodiments are presented solely to enable those skilled in the art to better understand and further practice the present disclosure, and are not intended to limit the scope of the present disclosure. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. In the interest of clarity, not all features of an actual implementation are described in this specification.

References in the specification to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a "first" element may also be referred to as a "second" element, and similarly, a "second" element may also be referred to as a "first" element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used herein, specify the presence of stated features, elements, and/or components, etc., but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

As used herein, the term "wireless communication network" refers to a network that conforms to any suitable wireless communication standard, such as LTE-advanced (LTE-a), LTE, Wideband Code Division Multiple Access (WCDMA), High Speed Packet Access (HSPA), NR, and the like. Further, communication between network devices in a wireless communication network may be performed according to any suitable generation of communication protocols, including but not limited to first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, and/or any other protocols currently known or to be developed in the future.

As used herein, the term "network device" refers to a device in a wireless communication network via which a terminal device accesses the network and receives services therefrom. A network device may refer to a Base Station (BS) or an Access Point (AP), e.g., a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), a gNodeB or gNB, a Remote Radio Unit (RRU), a Radio Header (RH), a Remote Radio Head (RRH), a relay, a low power node (such as a femto node, pico node, etc.), depending on the terminology and technology applied.

Yet another example of a network device includes a multi-standard radio (MSR) radio such as an MSR BS, a network controller such as a Radio Network Controller (RNC) or a Base Station Controller (BSC), a Base Transceiver Station (BTS), a transmission point, a transmission node, a multi-cell/Multicast Coordination Entity (MCE), a core network node (e.g., MSC, MME), an O & M node, an OSS node, a SON node, a positioning node (e.g., E-SMLC), and/or an MDT. More generally, however, the network device may represent any suitable device (or group of devices) that is capable, configured, arranged and/or operable to enable and/or provide terminal devices with access to and/or to provide some service to terminal devices that have access to the wireless communication network.

The term "terminal device" refers to any terminal device that can access a wireless communication network and receive services therefrom. By way of example, and not limitation, a terminal device may be referred to as a User Equipment (UE), Subscriber Station (SS), portable subscriber station, Mobile Station (MS), or Access Terminal (AT). The terminal devices may include, but are not limited to, mobile phones, cellular phones, smart phones, tablets, wearable devices, Personal Digital Assistants (PDAs), portable computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, wearable terminal devices, in-vehicle wireless terminal devices, and the like. In the following description, the terms "terminal device", "terminal", "user equipment" and "UE" may be used interchangeably.

In 3GPP TS 38.321 V15.2.0, random access resource selection and beam selection are specified in section 5.1.2. According to section 5.1.2 of the present invention,

"the MAC entity should:

1> if a random access procedure is initiated for beam failure recovery (as described in section 5.17); and is

1> if the beamFailureRecoveryTimer (in section 5.17) is running or not configured; and is

1> if a contention-free random access resource of a beam failure recovery request associated with any SSB and/or CSI-RS has been explicitly provided by RRC; and is

1> if at least one of the SSB of the candidateBeamRSList with SS-RSRP higher than RSRP-ThresholdSSB or the CSI-RS of the CandidateBeamRSList with CSI-RSRP higher than RSRP-ThresholdCSI-RS is available:

2> selecting an SSB with SS-RSRP higher than RSRP-threshold SSB among SSBs in candidateBeamRSList, or selecting a CSI-RS with CSI-RSRP higher than RSRP-threshold SI-RS among CSI-RSs in candidateBeamRSList;

2> if a CSI-RS is selected and there is no ra-preamblelndex associated with the selected CSI-RS:

3> set PREAMBLE _ INDEX to ra-PreambleIndex corresponding to SSB in the candidateBeamRSList quasi co-located with the selected CSI-RS specified in TS38.214[7 ].

2> otherwise:

3> set PREAMBLE _ INDEX to ra-PreambleIndex corresponding to the selected SSB or CSI-RS in the random access PREAMBLE set for the beam failure recovery request.

1> else, if ra-preamblelndex has been explicitly provided by PDCCH or RRC; and is

1> if ra-PreambleIndex is not 0b 000000; and is

1> if RRC has not explicitly provided contention-free random access resources associated with SSB or CSI-RS:

2> set PREAMBLE _ INDEX to the signaled ra-PreambbleIndex.

1> otherwise, if contention-free random access resources associated with the SSBs have been explicitly provided by RRC and at least one SS-RSRP higher than RSRP-threshold SSB among the associated SSBs is available:

2> selecting SSBs with SS-RSRP higher than RSRP-threshold SSB from the associated SSBs;

2> set PREAMBLE _ INDEX to ra-PreambleIndex corresponding to the selected SSB.

1> otherwise, if contention-free random access resources associated with the CSI-RS have been explicitly provided by RRC and at least one CSI-RS with a CSI-RSRP higher than RSRP-threshold CSI-RS among the associated CSI-RS is available:

2> selecting a CSI-RS with CSI-RSRP higher than RSRP-ThresholdCSI-RS from the associated CSI-RSs;

2> set PREAMBLE _ INDEX to ra-PreambleIndex corresponding to the selected CSI-RS.

1> otherwise:

2> if at least one SSB of the SSBs with SS-RSRP higher than RSRP-threshold SSB is available:

3> selecting SSB with SS-RSRP higher than RSRP-ThresholdSSB.

2> otherwise:

3> select any SSB.

… "(emphasis added.)

As can be seen from the above, an SSB or CSI-RS beam may be selected in order to determine the preamble to be used in the random access procedure. However, in the current section 5.1.3 "random access preamble transmission", no power boost behavior is defined for CSI-RS beams, nor for handovers between SSBs and CSI-RS beams.

Currently, the power boost in section 5.1.3 of 3GPP TS 38.321 V15.2.0 works as follows: "the MAC entity should, for each random access preamble:

1> if PREAMBLE _ transition _ COUNTER is greater than 1; and is

1> if no notification to halt the power up counter has been received from the lower layer; and is

1> if the selected SSB has not changed (i.e., is the same as the previous random access preamble transmission):

2> PREAMBLE _ POWER _ RAMPING _ COUNTER is incremented by 1.

1> select the value of DELTA _ PREAMBLE according to section 7.3;

1> set PREAMBLE _ RECEIVED _ TARGET _ POWER to PREAMBLE RECEIVEDTargetPOWER + DELTA _ PREAMBLE + (PREAMBLE _ POWER _ RAMPING _ COUNTER-1) x PREAMBLE _ POWER _ RAMPING _ STEP;

1> calculating an RA-RNTI associated with a PRACH opportunity to transmit a random access preamble in addition to a contention-free random access preamble for a beam failure recovery request;

1> instructs the physical layer to transmit the random access PREAMBLE using the selected PRACH, the corresponding RA-RNTI (if available), the PREAMBLE _ INDEX and the PREAMBLE _ RECEIVED _ TARGET _ POWER.

The RA-RNTI associated with the PRACH that transmits the random access preamble is calculated as follows:

RA-RNTI＝1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id

where s _ id is the index of the first OFDM symbol of the designated PRACH (0 ≦ s _ id <14), t _ id is the index of the first slot of the designated PRACH in the system frame (0 ≦ t _ id <80), f _ id is the index of the designated PRACH in the frequency domain (0 ≦ f _ id <8), UL _ carrier _ id is the UL carrier for Msg1 transmission (0 for NUL carrier, 1 for SUL carrier). "(emphasis added.)

The above specifies that in the case of SSBs (i.e. the power boosting is not performed whenever the selected SSB has changed from the previously selected SSB in the previous preamble transmission, this is done because the newly selected SSB may be of better quality than the previous SSB, and therefore increasing the preamble power may unnecessarily increase the uplink interference because the previously used transmit power is more than sufficient.

However, the inventors of the present disclosure found that such UE behavior is not always beneficial. For example, in certain specific cases, it may be desirable to perform power boosting to increase the transmit power of a preamble transmission attempt. If many subsequent preamble transmission attempts do not allow for power boosting, which may occur when a narrower downlink CSI-RS beam, this may delay the random access procedure completion and lead to unnecessary uplink Radio Link Failure (RLF) events.

In accordance with one or more embodiments of the present disclosure, the preamble power boost of the UE may be determined according to whether the selected beam of the SSB or CSI-RS is substantially different from a previously selected beam of the SSB or CSI-RS. If the properties of the selected beam of the SSB or CSI-RS are substantially the same/similar to the properties of the previously selected beam, UE power boosting needs to be performed to increase the random access preamble transmission power even if the beam has changed from one to another.

In accordance with one or more embodiments of the present disclosure, determining whether the selected beam of the SSB or CSI-RS is substantially different from a previous beam may be based on quasi co-location (QCL) assumptions between the two beams. According to section 5.1.5 of 3GPP TS38.214 release 15, when two different signals share the same QCL type, they share the same predefined attributes. As an example, the QCL properties may be e.g. delay spread, average delay, doppler spread, doppler shift, spatial receiver parameters. Currently, 38.214 lists the following QCL types:

- 'QCL-TypeA': { Doppler shift, Doppler spread, average delay, delay spread }

- 'QCL-TypeB': { Doppler shift, Doppler spread }

- 'QCL-TypeC': { Doppler shift, average delay }

- 'QCL-type': { space Rx parameter }

If the CSI-RS and the SSB share the same QCL type, e.g., type D, then there is a QCL assumption between each other, which means that the UE can receive these signals with the same RX spatial filter parameters. Thus, under the condition that two beams/signals have QCL assumptions, the two beams/signals may be considered substantially the same or similar in certain properties, depending on the type of QCL.

In one or more embodiments of the present disclosure, if a QCL can be assumed between the selected SSB/CSI-RS and the previously selected CSI-RS/SSB, the UE should boost the preamble transmission power; otherwise, it does not boost the preamble transmission power.

According to one embodiment, such power boosting may be allowed only when the network has not configured the RA resources (e.g., contention-based random access (CBRA)/contention-free random access (CFRA) resource/(preamble) s) associated with the selected CSI-RS for the UE. According to section 5.1.2 of 3GPP TS 38.321 V15.2.0, if a CSI-RS is selected and there is no random access PREAMBLE INDEX (ra-PREAMBLE INDEX) associated with the selected CSI-RS, then PREAMBLE _ INDEX is set to ra-PREAMBLE INDEX corresponding to the SSB in the candidateBeamRSList quasi co-located with the selected CSI-RS. In this case, the UE may select a preamble corresponding to an SSB quasi co-located with the selected CSI-RS.

If a QCL for the same SSB can be assumed for the selected CSI-RS and the previously selected CSI-RS (both CSI-RS are quasi co-located with the same SSB), the UE should boost the preamble transmission power; otherwise, it will not boost the preamble transmission power.

An example implementation of the main proposal for 3GPP TS 38.321 may be provided as follows.

5.1.3 random Access preamble Transmission

For each random access preamble, the MAC entity should:

1> if PREAMBLE _ transition _ COUNTER is greater than 1; and is

1> if no notification to halt the power up counter has been received from the lower layer; and is

1>If the selected SSB/CSI-RS is unchanged (i.e., the same as the previous random access preamble transmission),or The CSI-RS pair selected by the user is directed to the previous follow-upSSB selected for machine access preamble transmission with QCL assumptions, or selected The selected CSI-RS has QCL false for the same SSB as the CSI-RS selected for the previous random access preamble transmission Stator：

2> PREAMBLE _ POWER _ RAMPING _ COUNTER is incremented by 1.

1> select the value of DELTA _ PREAMBLE according to section 7.3;

1> set PREAMBLE _ RECEIVED _ TARGET _ POWER to PREAMBLE RECEIVEDTargetPOWER + DELTA _ PREAMBLE + (PREAMBLE _ POWER _ RAMPING _ COUNTER-1) x PREAMBLE _ POWER _ RAMPING _ STEP;

1> calculating an RA-RNTI associated with a PRACH opportunity to transmit a random access preamble in addition to a contention-free random access preamble for a beam failure recovery request;

1> instructs the physical layer to transmit the random access PREAMBLE using the selected PRACH, the corresponding RA-RNTI (if available), the PREAMBLE _ INDEX and the PREAMBLE _ RECEIVED _ TARGET _ POWER.

The RA-RNTI associated with the PRACH that transmits the random access preamble is calculated as follows:

RA-RNTI＝1+s_id+14×t_id+14×80×f_id+14×80×8×ul_carrier_id

where s _ id is the index of the first OFDM symbol of the designated PRACH (0 ≦ s _ id <14), t _ id is the index of the first slot of the designated PRACH in the system frame (0 ≦ t _ id <80), f _ id is the index of the designated PRACH in the frequency domain (0 ≦ f _ id <8), and UL _ carrier _ id is the UL carrier for Msg1 transmission (0 for NUL carrier and 1 for SUL carrier). (emphasis added.)

Fig. 2 shows a flow diagram of a method 200 implemented at a terminal device in accordance with one or more embodiments of the present disclosure.

As shown in fig. 2, in a random access procedure, the UE selects a beam for random access preamble transmission at block 210. The selected beam may be different from the beam selected for the previous random access preamble transmission.

In accordance with one or more embodiments of the present disclosure, when the UE performs beam selection for continuous random access preamble transmission, the UE may preferentially select a beam having a quasi-co-location assumption for a previously selected beam or for the same beam as the previously selected beam. That is, when beam selection is performed according to section 5.1.2 of 3GPP 38.321, quasi co-location assumptions between beams may also be considered.

In accordance with one or more embodiments of the present disclosure, the selected beam may be a beam of an SSB or CSI-RS, and the previously selected beam may also be a beam of an SSB or CSI-RS.

At block 220, the UE determines whether the selected beam has a quasi-co-location assumption for the previously selected beam, or whether both the selected beam and the previously selected beam have quasi-co-location assumptions for the same beam.

At block 230, the UE decides whether to boost the power of the random access transmission.

In accordance with one or more embodiments of the present disclosure, the UE may decide to boost the power of the random access preamble transmission in response to determining that the selected beam has a quasi co-location assumption for a previously selected beam or that both the selected beam and the previously selected beam have a quasi co-location assumption for the same beam.

In some embodiments, the power boost may be performed by incrementing the power for the random access preamble transmission by a predetermined power boost step size. The predetermined POWER RAMPING stepsize is achieved by incrementing a PREAMBLE POWER RAMPING COUNTER (such as PREAMBLE _ POWER _ RAMPING _ COUNTER specified in 3GPP TS 38.321) for random access PREAMBLE transmission by 1.

In some additional or alternative embodiments, the power ramping step size may have additional scaling when switching between two signals for consecutive random access attempts when based on QCL assumptions. The UE may perform power boosting for random access preamble transmission by incrementing the power for random access preamble transmission by a fraction of a predetermined power boosting step (e.g., only 0.25/0.5/0.75 x the normal power boosting step). Alternatively or additionally, the scaling may depend on the type of previously selected and currently selected downlink reference signals. For example, it may be defined that full boosting may be applied in case the selected beam is changed from CSI-RS to another CSI-RS with the same QCL source.

In accordance with one or more embodiments of the present disclosure, the selected power boost for the new beam may be performed only when no random access resource is associated with the selected beam of the CSI-RS.

According to one or more embodiments of the present disclosure, the QCL between two beams may be established on the condition that the two beams share one or more same attributes selected from the group consisting of: delay spread, mean delay, doppler spread, doppler shift, spatial receiver parameters.

Fig. 3 shows a schematic block diagram of an apparatus 300 implemented as/in a terminal device in accordance with one or more embodiments of the present disclosure.

As shown in fig. 3, a terminal device 300, such as a UE, is configured to communicate with one or more network devices, such as a gNB.

The terminal device 300 includes a selection unit 310, a determination unit 320, and a decision unit 330. Terminal device 300 may include a suitable radio-frequency transceiver for wireless communication with one or more network devices via one or more antennas (not shown in fig. 3).

The selecting unit 310 is configured to select a beam for random access preamble transmission in a random access procedure. The selected beam is different from the beam selected for the previous random access preamble transmission.

According to one or more embodiments of the present disclosure, when beam selection is performed for consecutive random access preamble transmissions, the terminal device 300 may preferentially select a beam having a quasi-co-location assumption for a previously selected beam or for the same beam as the previously selected beam. That is, when beam selection is performed according to section 5.1.2 of 3GPP 38.321, quasi co-location assumptions between beams may also be considered.

In accordance with one or more embodiments of the present disclosure, the selected beam may be a beam of an SSB or CSI-RS, and the previously selected beam may also be a beam of an SSB or CSI-RS.

The determining unit 320 is configured to determine whether the selected beam has a quasi co-location assumption for a previously selected beam or whether both the selected beam and the previously selected beam have a quasi co-location assumption for the same beam.

The deciding unit 330 is configured to decide whether to boost the power of the random access preamble transmission according to the determination.

In accordance with one or more embodiments of the present disclosure, the decision unit 330 may decide to boost the power of the random access preamble transmission in response to determining that the selected beam has a quasi co-location assumption for a previously selected beam or that both the selected beam and the previously selected beam have a quasi co-location assumption for the same beam.

In some embodiments, terminal device 300 may perform the power boost by incrementing the power for the random access preamble transmission by a predetermined power boost step size. The predetermined POWER RAMPING stepsize is achieved by incrementing a PREAMBLE POWER RAMPING COUNTER (such as PREAMBLE _ POWER _ RAMPING _ COUNTER specified in 3GPP TS 38.321) for random access PREAMBLE transmission by 1.

In some additional or alternative embodiments, the power ramping step size may have additional scaling when switching between two signals for consecutive random access attempts when based on QCL assumptions. The terminal device 300 may perform power boosting for random access preamble transmission by incrementing the power for random access preamble transmission by a fraction of a predetermined power boosting step (e.g., only 0.25/0.5/0.75 x the normal power boosting step). Alternatively or additionally, the scaling may depend on the type of previously selected and currently selected downlink reference signals. For example, it may be defined that full boosting may be applied in case the selected beam is changed from CSI-RS to another CSI-RS with the same QCL source.

According to one or more embodiments of the present disclosure, the terminal device 300 may be configured to perform the power boosting for the selection of the new beam only when no random access resource is associated with the selected beam of the CSI-RS.

According to one or more embodiments of the present disclosure, the QCL between two beams may be established on the condition that the two beams share one or more same attributes selected from the group consisting of: delay spread, mean delay, doppler spread, doppler shift, spatial receiver parameters.

Terminal device 300 may include a processor 30 (which includes one or more microprocessors or microcontrollers), as well as other digital hardware, which may include a Digital Signal Processor (DSP), dedicated digital logic, or the like. The processor 30 may be configured to execute program code stored in a memory (not shown in fig. 3), which may include one or several types of memory, such as Read Only Memory (ROM), random access memory, cache memory, flash memory devices, optical storage devices, and so forth. In some embodiments, program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols and instructions for performing one or more of the techniques described herein. In some implementations, the processor 30 may be configured to cause the selection unit 310, the determination unit 320 and the decision unit 330, as well as any other suitable unit of the terminal device 300, to perform corresponding functions in accordance with one or more embodiments of the present disclosure.

Fig. 4 shows a simplified block diagram of an apparatus 410 that may be implemented/embodied in a terminal device (e.g., terminal device 300) and an apparatus 420 that may be implemented/embodied in a network device (e.g., gNB).

The apparatus 410 may include one or more processors 411, such as a Data Processor (DP), and one or more memories (MEM)412 coupled to the processors 411. The apparatus 410 may also include a transmitter TX and a receiver RX 413 coupled to the processor 411. The MEM 412 may be a non-transitory machine-readable storage medium and may store a Program (PROG) 414. The PROG 414 may include instructions that, when executed on the associated processor 411, enable the apparatus 410 to operate in accordance with embodiments of the disclosure, e.g., to perform the method 200. The combination of one or more processors 411 and one or more MEMs 412 may form a processing component 415 suitable for implementing various embodiments of the present disclosure.

The apparatus 420 includes one or more processors 421 (such as a DP) and one or more MEMs 422 coupled to the processors 421. The apparatus 420 may also include a suitable TX/RX 423 coupled to the processor 421. The MEM 422 may be a non-transitory machine-readable storage medium and may store the PROG 424. PROG 424 may include instructions that, when executed on associated processor 421, enable apparatus 420 to communicate with apparatus 410. The combination of one or more processors 421 and one or more MEMs 422 may form a processing component 425 suitable for implementing the functionality of a network device such as a gNB.

The MEMs 412 and 422 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory terminal devices, magnetic memory terminal devices and systems, optical memory terminal devices and systems, fixed memory and removable memory, as non-limiting examples.

The processors 411 and 421 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors, DSPs, and processors based on a multi-core processor architecture, as non-limiting examples.

Additionally, the present disclosure may also provide a memory containing a computer program as described above, the memory including a machine-readable medium and a machine-readable transmission medium. The machine-readable medium may also be referred to as a computer-readable medium and may include a machine-readable storage medium, such as a magnetic disk, magnetic tape, optical disk, phase change memory, or electronic memory terminal device, such as Random Access Memory (RAM), Read Only Memory (ROM), flash memory device, CD-ROM, DVD, Blu-ray disk, and so forth. A machine-readable transmission medium may also be referred to as a carrier and may include, for example, electrical, optical, radio, acoustic, or other form of propagated signals, such as carrier waves, infrared signals, etc.

The techniques described herein may be implemented by various means, so that an apparatus implementing one or more functions of a corresponding apparatus described by an embodiment includes not only the related art means but also means for implementing one or more functions of a corresponding apparatus described by an embodiment, and it may include separate means for each separate function or may include means that may be configured to perform two or more functions. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or a combination thereof. For firmware or software, implementation can be through modules (e.g., procedures, functions, and so on) that perform the functions described herein.

Example embodiments herein have been described above with reference to block diagrams and flowchart illustrations of methods and apparatus devices. It should be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, can be implemented by various means, including hardware, software, firmware, and combinations thereof. For example, in one embodiment, each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be loaded onto a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions which execute on the computer or other programmable data processing apparatus create means for implementing the functions specified in the flowchart block or blocks.

Further, while operations are depicted 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. In some cases, multitasking and parallel processing may be advantageous. Also, while several specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the subject matter described herein, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this specification 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 subcombination. Furthermore, 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 subcombination or variation of a subcombination.

It is clear to a person skilled in the art that with the advancement of technology, the inventive concept may be implemented in various ways. The above-described embodiments are given for the purpose of illustration and not limitation of the present disclosure, and it is to be understood that modifications and variations may be made without departing from the spirit and scope of the disclosure, as will be readily understood by those skilled in the art. Such modifications and variations are considered to be within the scope of the disclosure and the appended claims. The scope of the disclosure is defined by the appended claims.