WO2020248887A1

WO2020248887A1 - Method and apparatus for antenna panel control

Info

Publication number: WO2020248887A1
Application number: PCT/CN2020/094314
Authority: WO
Inventors: Hsinhsi TSAI; Chiahung Wei; Chieming CHOU
Original assignee: FG Innovation Company Limited
Priority date: 2019-06-11
Filing date: 2020-06-04
Publication date: 2020-12-17

Abstract

A method for antenna panel control performed by a UE is provided. The method includes: initiating a random access (RA) procedure; performing transmission, via a first antenna panel of the plurality of antenna panels, during the RA procedure; receiving, from a base station (BS), an antenna panel control message during the RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels; and ignoring the antenna panel control message.

Description

METHOD AND APPARATUS FOR ANTENNA PANEL CONTROL

CROSS-REFERENCE TO RELATED APPLICATION (S)

The present disclosure claims the benefit of and priority of provisional U.S. Patent Application Serial No. 62/859,889, filed on June 11, 2019, entitled “Method and apparatus for panel control during random access procedure in a wireless communication system” ( “the ’889 provisional” ) . The disclosure of the ’889 provisional is hereby incorporated fully by reference into the present disclosure.

FIELD

The present disclosure is related to wireless communication, and more particularly, to a method for controlling antenna panels in cellular wireless communication networks.

BACKGROUND

Abbreviations used in this disclosure:

Abbreviation Full name

3GPP 3 ^rd Generation Partnership Project

5G 5 ^th Generation

BFR Beam Failure Recovery

BS Base Station

BWP Bandwidth Part

CE Control Element

CSI Channel State Information

CSI-RS Channel State Information based Reference Signal

DCI Downlink Control Information

DL Downlink

FR Frequency Range

LTE Long Term Evolution

MAC Medium Access Control

MIMO Multi-Input Multi-Output

Msg Message

NR New RAT/Radio

NW Network

PCell Primary Cell

PDCCH Physical Downlink Control Channel

PDSCH Physical Downlink Shared Channel

PDU Protocol Data Unit

PHY Physical

PRACH Physical Random Access Channel

PSCCH Physical Sidelink Control Channel

PSFCH Physical Sidelink Feedback Channel

PSSCH Physical Sidelink Shared Channel

PUCCH Physical Uplink Control Channel

PUSCH Physical Uplink Shared Channel

RA Random Access

RAR Random Access Response

RF Radio Frequency

RNTI Radio Network Temporary Identifier

RRC Radio Resource Control

RS Reference Signal

RSRP Reference Signal Received Power

SCell Secondary Cell

SDU Service Data Unit

SINR Signal to Interference plus Noise Ratio

SL SideLink

SR Scheduling Request

SRS Sounding Reference Signal

SSB Synchronization Signal Block

TA Timing Alignment /Timing Advance

TCI Transmission Configuration Indication

TR Technical Report

TRP Transmission /Reception Point

TS Technical Specification

UE User Equipment

UL Uplink

UL-SCH Uplink Shared Channel

URLLC Ultra-Reliable Low Latency Communication

Various efforts have been made to improve different aspects of wireless communications, such as data rate, latency, reliability and mobility, for cellular wireless communication systems (e.g., 5G NR) . Supporting carrier frequencies up to 100GHz brings a number of challenges in the area of radio propagation. As the carrier frequency increases, the path loss also increases. In lower frequency bands (e.g., < 6GHz) the required cell coverage may be provided by forming a wide sector beam for transmitting downlink common channels. However, the cell coverage is reduced with the same antenna gain when utilizing wide sector beam on higher frequencies (e.g., > 6GHz) . Thus, in order to provide required cell coverage on higher frequency bands, higher antenna gain is needed to compensate the increased path loss. Larger antenna arrays (number of antenna elements ranging from tens to hundreds) are used to form high gain beams to increase the antenna gain.

The high gain beams are narrow compared to a wide sector beam, so multiple beams for transmitting downlink common channels are needed to cover the required cell area. The number of concurrent high gain beams that an access point is able to form may be limited by the cost and complexity of the utilized transceiver architecture. In practice, on higher frequencies, the number of concurrent high gain beams is much less than the total number of beams required to cover the cell area. In other words, the access point is able to cover only part of the cell area by using a subset of beams at any given time.

Beamforming is a signal processing technique used in antenna arrays for directional signal transmission/reception. With beamforming, a beam can be formed by combining elements in a phased array of antennas in such a way that signals at particular angles experience constructive interference while others experience destructive interference. Different beams can be utilized simultaneously using multiple arrays of antennas. In addition, a base station (e.g., a gNB) may have multiple TRPs (either centralized or distributed) . Each TRP may form multiple beams. The number of beams and the number of simultaneous beams in the time/frequency domain depend on the number of antenna array elements and the RF circuit at the TRP.

A collection of antenna elements is needed to perform beamforming. By tuning the phase and optionally gain of a signal input to individual antenna elements, a beam with different characteristics is formed. Based on implementation, a certain collection of antenna elements may be controlled at the same time as an entity (which may also be referred to as a panel, an antenna panel, or a UE panel in the following disclosure) to form one beam. Depending on implementation, different panels may be activated at the same time to form individual beams. The UE may need multiple panels to achieve omni-directional/isotropic spatial coverage. There is a need in the industry for an improved and efficient mechanism for the UE to control panel related operations.

SUMMARY

The present disclosure is directed to a method for antenna panel control performed by a UE in cellular wireless communication networks.

According to an aspect of the present disclosure, a method for antenna panel control performed by a UE is provided. The method includes: initiating an RA procedure; performing transmission, via a first antenna panel of the plurality of antenna panels, during the RA procedure; receiving, from a BS, an antenna panel control message during the RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels; and ignoring the antenna panel control message.

According to another aspect of the present disclosure, a method for antenna panel control performed by a UE is provided. The method includes: initiating an RA procedure; performing transmission, via a first antenna panel of the plurality of antenna panels, during the RA procedure; receiving, from a BS, an antenna panel control message during the first RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels; stopping the first RA procedure; initiating a second RA procedure; and performing transmission, via a second antenna panel of the plurality of antenna panels, during the second RA procedure.

According to yet another aspect of the present disclosure, a UE is provided that includes a plurality of antenna panels, one or more non-transitory computer-readable media containing computer-executable instructions embodied therein and at least one processor coupled to the one or more non-transitory computer-readable media. The at least one processor is configured to execute the computer-executable instructions to: initiate an RA procedure; perform transmission, via a first antenna panel of the plurality of antenna panels, during the RA procedure; receive, from a BS, an antenna panel control message during the RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels; and ignore the antenna panel control message.

According to still yet another aspect of the present disclosure, a UE is provided that includes a plurality of antenna panels, one or more non-transitory computer-readable media containing computer-executable instructions embodied therein and at least one processor coupled to the one or more non-transitory computer-readable media. The at least one processor is configured to execute the computer-executable instructions to: initiate an RA procedure; perform transmission, via a first antenna panel of the plurality of antenna panels, during the RA procedure; receive, from a BS, an antenna panel control message during the first RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels; stop the first RA procedure; initiate a second RA procedure; and perform transmission, via a second antenna panel of the plurality of antenna panels, during the second RA procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying drawings. Various features are not drawn to scale. Dimensions of various features may be arbitrarily increased or reduced for clarity of discussion.

Fig. 1A includes a diagram illustrating a contention-based random access (CBRA) procedure according to an example implementation of the present disclosure.

Fig. 1B includes a diagram illustrating a contention-free random access (CFRA) procedure, according to an example implementation of the present application.

Fig. 2 includes a diagram illustrating a two-step RA procedure, according to an example implementation of the present application.

Fig. 3 includes a diagram illustrating an example multi-panel operation, according to an example implementation of the present application.

Fig. 4 includes a diagram illustrating an example panel activation/deactivation operation, according to an example implementation of the present application.

Fig. 5 includes a diagram illustrating an example panel switching operation, according to an example implementation of the present application.

Fig. 6 is a flowchart of a method for antenna panel control according to an example implementation of the present disclosure.

Fig. 7 is a flowchart of a method for antenna panel control according to another example implementation of the present disclosure.

Fig. 8 is a block diagram illustrating a node for wireless communication according to the present disclosure.

DETAILED DESCRIPTION

The following description contains specific information related to implementations of the present disclosure. The drawings and their accompanying detailed description are merely directed to implementations.

However, the present disclosure is not limited to these implementations. Other variations and implementations of the present disclosure will be obvious to those skilled in the art.

Unless noted otherwise, like or corresponding elements among the drawings may be indicated by like or corresponding reference numerals. Moreover, the drawings and illustrations in the present disclosure are generally not to scale and are not intended to correspond to actual relative dimensions.

For the purpose of consistency and ease of understanding, like features may be identified (although, in some examples, not shown) by the same numerals in the drawings. However, the features in different implementations may be different in other respects and shall not be narrowly confined to what is shown in the drawings.

The phrases “in one implementation, ” or “in some implementations, ” may each refer to one or more of the same or different implementations. The term “coupled” is defined as connected whether directly or indirectly through intervening components and is not necessarily limited to physical connections. The term “comprising” means “including, but not necessarily limited to” and specifically indicates open-ended inclusion or membership in the so-described combination, group, series or equivalent. The expression “at least one of A, B and C” or “at least one of the following: A, B and C” means “only A, or only B, or only C, or any combination of A, B and C. ”

The terms “system” and “network” may be used interchangeably. The term “and/or” is only an association relationship for describing associated objects and represents that multiple relationships may exist such that A and/or B may indicate that A exists alone, A and B exist at the same time, or B exists alone. The character “/” generally represents that the associated objects are in an “or” relationship.

For the purposes of explanation and non-limitation, specific details such as functional entities, techniques, protocols, and standards are set forth for providing an understanding of the present disclosure. In other examples, detailed description of well-known methods, technologies, systems, and architectures are omitted so as not to obscure the description with unnecessary details.

Persons skilled in the art will recognize that any network function (s) or algorithm (s) disclosed may be implemented by hardware, software or a combination of software and hardware. Disclosed functions may correspond to modules which may be software, hardware, firmware, or any combination thereof.

A software implementation may include computer executable instructions stored on a computer readable medium such as memory or other type of storage devices. One or more microprocessors or general-purpose computers with communication processing capability may be programmed with corresponding executable instructions and perform the disclosed network function (s) or algorithm (s) .

The microprocessors or general-purpose computers may include Applications Specific Integrated Circuitry (ASIC) , programmable logic arrays, and/or using one or more Digital Signal Processor (DSPs) . Although some of the present disclosure is directed to software installed and executing on computer hardware, alternative implementations as firmware or as hardware or combination of hardware and software are well within the scope of the present disclosure. The computer readable medium includes but is not limited to Random Access Memory (RAM) , Read Only Memory (ROM) , Erasable Programmable Read-Only Memory (EPROM) , Electrically Erasable Programmable Read-Only Memory (EEPROM) , flash memory, Compact Disc Read-Only Memory (CD-ROM) , magnetic cassettes, magnetic tape, magnetic disk storage, or any other equivalent medium capable of storing computer-readable instructions.

A radio communication network architecture such as a Long Term Evolution (LTE) system, an LTE-Advanced (LTE-A) system, an LTE-Advanced Pro system, or a 5G NR Radio Access Network (RAN) typically includes at least one base station (BS) , at least one UE, and one or more optional network elements that provide connection within a network. The UE communicates with the network such as a Core Network (CN) , an Evolved Packet Core (EPC) network, an Evolved Universal Terrestrial RAN (E-UTRAN) , a 5G Core (5GC) , or an internet via a RAN established by one or more BSs.

A UE may include but is not limited to a mobile station, a mobile terminal or device, or a user communication radio terminal. The UE may be portable radio equipment that includes but is not limited to a mobile phone, a tablet, a wearable device, a sensor, a vehicle, or a Personal Digital Assistant (PDA) with wireless communication capability. The UE is configured to receive and transmit signals over an air interface to one or more cells in a RAN.

The BS may be configured to provide communication services according to at least a Radio Access Technology (RAT) such as Worldwide Interoperability for Microwave Access (WiMAX) , Global System for Mobile communications (GSM) that is often referred to as 2G, GSM Enhanced Data rates for GSM Evolution (EDGE) RAN (GERAN) , General Packet Radio Service (GPRS) , Universal Mobile Telecommunication System (UMTS) that is often referred to as 3G based on basic wideband-code division multiple access (W-CDMA) , high-speed packet access (HSPA) , LTE, LTE-A, evolved LTE (eLTE) that is LTE connected to 5GC, NR (often referred to as 5G) , and/or LTE-A Pro. However, the scope of the present disclosure is not limited to these protocols.

The BS may include but is not limited to a node B (NB) in the UMTS, an evolved node B (eNB) in LTE or LTE-A, a radio network controller (RNC) in UMTS, a BS controller (BSC) in the GSM/GERAN, a ng-eNB in an E-UTRA BS in connection with 5GC, a next generation Node B (gNB) in the 5G-RAN, or any other apparatus capable of controlling radio communication and managing radio resources within a cell. The BS may serve one or more UEs via a radio interface.

The BS is operable to provide radio coverage to a specific geographical area using a plurality of cells forming the RAN. The BS supports the operations of the cells. Each cell is operable to provide services to at least one UE within its radio coverage.

Each cell (often referred to as a serving cell) provides services to serve one or more UEs within its radio coverage such that each cell schedules the downlink (DL) and optionally uplink (UL) resources to at least one UE within its radio coverage for DL and optionally UL packet transmissions. The BS can communicate with one or more UEs in the radio communication system via the plurality of cells.

A cell may allocate sidelink (SL) resources for supporting Proximity Service (ProSe) or Vehicle to Everything (V2X) service. Each cell may have overlapped coverage areas with other cells.

As discussed previously, the frame structure for NR supports flexible configurations for accommodating various next generation (e.g., 5G) communication requirements such as Enhanced Mobile Broadband (eMBB) , Massive Machine Type Communication (mMTC) , and Ultra-Reliable and Low-Latency Communication (URLLC) , while fulfilling high reliability, high data rate and low latency requirements. The Orthogonal Frequency-Division Multiplexing (OFDM) technology in the 3rd Generation Partnership Project (3GPP) may serve as a baseline for an NR waveform. The scalable OFDM numerology such as adaptive sub-carrier spacing, channel bandwidth, and Cyclic Prefix (CP) may also be used.

Two coding schemes are considered for NR, specifically Low-Density Parity-Check (LDPC) code and Polar Code. The coding scheme adaption may be configured based on channel conditions and/or service applications.

At least DL transmission data, a guard period, and an UL transmission data should be included in a transmission time interval (TTI) of a single NR frame. The respective portions of the DL transmission data, the guard period, and the UL transmission data should also be configurable based on, for example, the network dynamics of NR. SL resources may also be provided in an NR frame to support ProSe services or V2X services.

An RA procedure may be triggered by one or more of the following events:

- Initial access from RRC_IDLE;

- RRC Connection Re-establishment procedure;

- DL or UL data arrival during RRC_CONNECTED when UL synchronisation status is "non-synchronised" ;

- UL data arrival during RRC_CONNECTED when there are no PUCCH resources for SR available;

- SR failure;

- Request by RRC upon synchronous reconfiguration (e.g., handover) ;

- Transition from RRC_INACTIVE;

- To establish time alignment at SCell addition;

- Request for Other SI;

- Beam failure recovery.

Fig. 1A includes a diagram 100A illustrating a contention-based random access (CBRA) procedure according to an example implementation of the present disclosure. In action 132, UE 110 transmits a message 1 (Msg1) to base station 120. UE 110 may perform a random access preamble transmission via Msg1 (e.g., transmit a random access preamble using the selected PRACH occasion, corresponding RA-RNTI, preamble index and/or a preamble received target power) . In action 134, base station 120 transmits a message 2 (Msg2) , which may include a Random Access Response (RAR) , to UE 110. UE 110 may receive an RAR from base station 120 via Msg2 (e.g., the UE 110 monitors a PDCCH transmission addressed to a RA-RNTI or C-RNTI) . The Msg2 may carry resource allocation information, such as a UL grant, for a message 3 (Msg3) transmission. After UE 110 successfully decodes the RAR, in action 136, UE 110 sends the Msg3 on the granted resource to base station 120. The Msg3 may be a MAC PDU stored in the Msg3 buffer. In action 138, base station 120 sends a message 4 (Msg4) to UE 110. The Msg4 may include a contention resolution MAC Control Element (CE) . The Msg4 may be a PDCCH transmission, and the UE 110 may monitor the PDCCH transmission while a contention resolution timer (e.g., ra-contentionresolutionTimer) is running.

Fig. 1B includes a diagram 100B illustrating a contention-free random access (CFRA) procedure, according to an example implementation of the present application. In action 140, base station 120 assigns a preamble to UE 110. In action 142, UE 110 transmits a Msg1 to base station 120. In action 144, base station 120 transmits a Msg2, which may include an RAR, to UE 110.

Fig. 2 includes a diagram 200 illustrating a two-step RA procedure, according to an example implementation of the present application. In action 232, UE 210 transmits a PRACH preamble and associated MsgA PUSCH on a configured time and frequency resource, where MsgA PUSCH may carry at least contents equivalent to the Msg3 in a 4-step RA procedure illustrated in Fig. 1A and Fig. 1B. Further, after successful detection of the PRACH preamble and decoding of the MsgA PUSCH, in action 234, base station 220 transmits MsgB that may carry contents equivalent to the Msg2 and Msg4 in the 4-step RA procedure illustrated in Fig. 1A and Fig. 1B.

Some or all of the following terminology/assumption may be used hereafter.

TRP: a transmission and reception point that provides network coverage and directly communicates with UEs. A TRP may be referred to as a distributed unit (DU) or a network node or a remote unit (RU) .

Cell: a cell may be composed of one or multiple associated TRPs. Coverage of the cell may be composed of coverage of all associated TRP (s) . A cell may be referred to as a TRP group (TRPG) or a network entity with scheduling feature.

An identifier (ID) may be used for indicating a panel-specific UL transmission. In one implementation, an ID that is supported in the Rel-15 specification may be reused or modified to fit various implementations in this disclosure. In one implementation, a new ID may be introduced. Implementations related to the ID for indicating the panel-specific UL transmission may include:

- The ID may be an SRS resource set ID.

- The ID may be associated with a reference RS resource and/or resource set.

- The ID may be assigned to a target RS resource or resource set.

- The ID may be additionally configured in spatial relation information.

UE capability signalling may be introduced for panel-specific UL transmission.

The categories of the multi-panel UE (MPUE) may include:

- MPUE-Assumption1: Multiple panels are implemented on a UE and only one panel can be activated at a time, with panel switching/activation delay of X ms, where X is a positive real number.

- MPUE-Assumption2: Multiple panels are implemented on a UE and multiple panels can be activated at a time and one or more panels can be used for transmission.

- MPUE-Assumption3: Multiple panels are implemented on a UE and multiple panels can be activated at a time but only one panel can be used for transmission.

A BS (e.g., a gNB) may configure/indicate panel-specific UL transmission via

- Alternative #1: Introduce a new UL-TCI framework that supports UL-TCI based signaling analogous to DL beam indication supported in the Rel-15 specification. In the new UL-TCI framework:

- A new panel ID may or may not be introduced.

- A panel specific signaling may be performed using UL-TCI state.

- Alternative #2: Introduce a new panel ID that may be implicitly/explicitly applied to the transmission for a target RS resource or resource set, for PUCCH resource, for SRS resource, and for PRACH resource.

- A panel specific signaling may be performed using the new panel ID implicitly (e.g., by DL beam reporting enhancement) or explicitly.

- The panel ID may be explicitly configured in the target RS/channel or reference RS (e.g., in the DL RS resource configuration or in spatial relation information) .

In order to ensure the efficiency of multi-beam operation in UL/DL transmission, a UE may be equipped with multiple antenna panels, e.g., multiple Tx/Rx units. An antenna panel may be a unit of antenna group (e.g., a group of antenna elements) to control beam independently, to control its transmission power, and/or to control its transmission timing. In one implementation, multiple panels at UE side may be activated at a time for simultaneous UL/DL transmission, which may achieve diversity gain and robustness against interference, deep fading and blocking.

Fig. 3 includes a diagram 300 illustrating an example multi-panel operation, according to an example implementation of the present application. UE 310 may be equipped with four

panels

322, 324, 326 and 328. In one implementation, different panels may be used to communicate with the same TRP (e.g., panel #1 322 and panel #2 324 are used to communicate with TRP #1 332) . In one implementation, different panels may be used to communicate with different TRPs (e.g., panel #3 326 is used to communicate with TRP #2 334 and panel #4 is used to communicate with TRP #3 336) . However, power consumption may be significant if UE 310 keeps activating panels no matter whether these panels are used or not. For example, an activated panel may need to maintain the beam quality constantly, which may consume power due to resource measurement or channel monitoring. In one implementation, only one panel or a subset of panels may be used for transmission at a time. In this sense, it may be beneficial to perform measurement once a while to control multi-panel operation, including panel activation/deactivation and/or panel switching.

Case 1-1: panel activation/deactivation

From the network’s perspective, the network does not require a UE to always activate multiple panels simultaneously, which may result in system performance loss. The network may control the state (or status) of the panels, e.g., via network indication. From the UE’s perspective, it may be more flexible to control the state of the UE panels by the UE itself. In one implementation, control of the UE panels may be a UE optional feature, with taking UE’s implementation complexity and functional flexibility into consideration. The UE may control panel activation or deactivation with consideration of UE power saving and/or system performance. In one implementation, the UE may periodically or aperiodically report the panel state to the network to align understanding on UE panel status between the network and the UE.

In one implementation, the state of UE panels may include at least one of activated panel (s) and deactivated panel (s) . For example, the state of UE panels may be controlled by an indication with a bitmap, with each bit corresponding to an activation/deactivation status of one panel. In another example, the state of UE panels may be controlled by an indication with index (es) corresponding to activated (or deactivated) panel (s) .

In one implementation, if panel activation/deactivation is controlled by the network, the UE may inform related information to the network. Such information may give assistance to the network. The number of simultaneous activated panels may be determined by UE capacity and/or TRP configuration to make a compromise between system performance and latency.

The UE capability for UE panel may include at least one or more than one of the following information:

- The number of UE panels;

- The number of different Tx beams on each panel; and

- Latency required for UE panel activation.

The network indication for panel activation/deactivation may be included in an RRC configuration/message, MAC control element, and/or PHY signaling (e.g., DCI) .

Fig. 4 includes a diagram 400 illustrating an example panel activation/deactivation operation, according to an example implementation of the present application. UE 410 is equipped with four

panels

422, 424, 426 and 428. As shown in the upper part of Fig. 4, panel #1 422 and panel #2 424 are activated, and panel #3 426 and panel #4 428 are deactivated. In one implementation, UE 410 may receive a network indication to turn on (activate) panel #3 426 and panel #4 428 and turn off (deactivate) panel #1 422 and panel #2 424. In one implementation, UE 410 may control by itself to turn on (activate) panel #3 426 and panel #4 428 and turn off (deactivate) panel #1 422 and panel #2 424. As shown in the lower part of Fig. 4, panel #1 422 and panel #2 424 are deactivated, and panel #3 426 and panel #4 428 are activated.

Case 1-2: panel switching

In one implementation, the NW may indicate UE to switch the panel for transmission. In one implementation, the panel for transmission may be selected among the activated panels. In one implementation, an activated panel may include at least two transmission states: activated panel used for transmission and activated panel not used for transmission. In one implementation, an identifier of the panel may be used to indicate panel-specific UL transmission.

In one implementation, the network indication for panel switching may be included in a RRC configuration, MAC control element, or PHY signaling (e.g., DCI) . In one implementation, the transmission may be a PRACH, PUCCH, PUSCH, SL (e.g., PSFCH, PSSCH, PSCCH) and/or SRS transmission.

Fig. 5 includes a diagram 500 illustrating an example panel switching operation, according to an example implementation of the present application. UE 510 is equipped with four

panels

522, 524, 526 and 528. Panel #1 522 and panel #2 524 are activated, and panel #3 526 and panel #4 528 are deactivated. As shown in the upper part of Fig. 5, panel #1 522 is used for transmission between UE 510 and TRP 530. UE 510 may receive an indication from network for panel switching. The indication is to request UE 510 to switch the panel for transmission from panel #1 522 to panel #2 524. As shown in the lower part of Fig. 5, panel #2 524 is used for transmission instead of panel #1 522. In one implementation, different panels may be used for transmission on different channels. In one implementation, panel #1 522 may be used for PRACH transmission, and panel #2 524 may be used for PUCCH/PUSCH transmission. In one implementation, a same panel may be used for transmission on different channels. In one implementation, panel #1 522 may be used for PRACH/PUCCH/PUSCH transmission.

In a random access procedure, the UE may perform PRACH/preamble transmission (which is the first step of the RA procedure) , and the UE may expect to receive a random access response (RAR) from network (which is the second step of the RA procedure) . The UE may start to monitor PDCCH for RAR (identified by the RA-RNTI) during a window (e.g., configured by a parameter ra-ResponseWindow) after transmitting the preamble. The UE may consider the RAR reception not successful and/or consider the RA procedure not completed if the UE does not successfully receive the RAR during the window (for example, the UE does not receive the RAR containing random access preamble identifiers that matches the transmitted preamble index) . Then the UE may perform the next attempt of the RA procedure (e.g., to perform RA resource selection procedure) . There may be other reasons to cause the RA procedure failure in addition to unsuccessful RAR reception, such as an unsuccessful contention resolution. A first attempt of the RA procedure and a second attempt of the RA procedure may be related to the same RA procedure.

Based on panel-specific UL transmission, the UE may use a panel for PRACH transmission. For example, the UE may transmit a preamble on PRACH resource via one of the UE panels. The UE panel (s) used for PRACH/preamble transmission may be selected by UE and/or configured/indicated by the network. In one implementation, at least one specific panel identifier may be implicitly or explicitly used to indicate which panel is used for PRACH transmission.

The UE may receive an indication from the network to deactivate a panel when the UE is performing a RA procedure via the panel, e.g., the UE is performing the transmission during the RA procedure via the panel. The transmission (during the RA procedure) mentioned in the present disclosure may be a DL transmission (e.g., PDCCH, PDSCH, RAR, Msg2, Msg4, MsgB, etc. ) and/or a UL transmission (e.g., PUCCH, PUSCH, PRACH, Msg1, Msg3, MsgA, etc. ) . For example, if the UE is equipped with four panels, two of them are activated, and two of them are deactivated. The NW may transmit an indication to deactivate one of the activated panels to reduce UE’s power consumption or increase system efficiency. Although the network may not arbitrarily deactivate a UE panel if the network knows the UE is using the panel to perform the RA procedure and/or the transmission during the RA procedure. In some cases the network may not know the UE is performing the RA procedure, such as a contention-based RA that is triggered by the UE itself. Therefore, a mechanism may be needed if the UE receives an indication from NW to deactivate the panel that is used for an (ongoing) RA procedure and/or the transmission during the RA procedure.

Case 2: panel activation/deactivation indication during an RA procedure

Referring to the upper part of Fig. 4, panel #1 422 and panel #2 424 are activated, and panel #3 426 and panel #4 428 are deactivated. UE 410 may perform a random access procedure via the panel #1 422 (e.g., for PRACH transmission) . UE 410 may receive an indication from NW to activate or deactivate a panel during the random access procedure (at any time during the RA procedure) . UE 410 may use panel #1 422 to transmit Msg1 and/or Msg 3 during the random access procedure. The indication from the NW may be transmitted via Msg 2 and/or Msg 4 during the random access procedure. In one implementation, the indication may be a specific indication rather than Msg 2 and/or Msg 4, such as a DCI, a MAC CE, and/or an RRC configuration via PDCCH or PDSCH. Referring to Fig. 1A, the panel activation/deactivation indication during the RA procedure may be transmitted in action 134, in action 138, or any time after action 132 (e.g., between action 132 and action 134) . Referring to Fig. 1B, the panel activation/deactivation indication during the RA procedure may be transmitted in action 144 or any time after action 142 (e.g., between action 142 and action 144) .

Referring to Fig. 2, for the two-step RA procedure, panel #1 may be used to transmit MsgA and/or receive MsgB. The panel activation/deactivation indication from the NW may be transmitted via MsgB or carried in a DCI or MAC CE or RRC configuration via PDCCH or PDSCH. The panel activation/deactivation indication during the RA procedure may be transmitted in action 234 or any time after action 232 (e.g., between action 232 and action 234) .

When the UE receives an indication from NW to activate or deactivate a panel during the random access procedure, the UE may perform one or more of the following actions. If the UE performs multiple actions below, the order for performing the actions is not limited. For example, the UE may stop the RA procedure first and then re-initiate a new RA procedure.

Case 2-1: UE does not deactivate the panel and continues with the ongoing RA procedure

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #1) that is used for the random access procedure (e.g., used for the transmission during the random access procedure) , the UE may not deactivate the panel (e.g., panel #1) and continue with the ongoing random access procedure. In one implementation, the UE may ignore the indication.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #2) that is not used for the random access procedure (e.g., not used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #2) and continue with the ongoing random access procedure via panel #1. In one implementation, the UE may not ignore the indication.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to activate a panel (e.g., panel #3) that is originally deactivated, the UE may activate the panel (e.g., panel #3) and continue with the ongoing random access procedure. In one implementation, the UE may use one or more of the activated panels (e.g., panel #1 and/or panel #3) to continue with the ongoing random access procedure and/or to perform the transmission during the RA procedure.

Case 2-2: UE deactivates the panel and re-initiates a new RA procedure via another activated panel

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #1) that is used for the random access procedure (e.g., used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #1) and re-initiate a new RA procedure. For example, the UE may perform random access procedure initialization.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #2) that is not used for the random access procedure (e.g., not used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #2) and not re-initiate a new RA procedure.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to activate the a panel (e.g., panel #3) that is originally deactivated, the UE may activate the panel (e.g., panel #3) and not re-initiate a new RA procedure. In one implementation, the UE may use one or more of the activated panels (e.g., panel #1 and/or panel #3) to continue with the ongoing random access procedure and/or to perform the transmission during the RA procedure.

In one implementation, (PRACH) transmission of the new RA procedure may be transmitted via another activated panel (e.g., panel #2) or a default panel. The default panel may be a panel that cannot be deactivated.

In one implementation, the UE may stop the original RA procedure if the UE re-initiates a new RA procedure.

In one implementation, the Msg3 buffer may be flushed if the UE re-initiates a new RA procedure.

In one implementation, the preamble transmission counter may be reset if the UE re-initiates a new RA procedure.

In one implementation, the preamble power ramping counter may be reset if the UE re-initiates a new RA procedure.

In one implementation, the preamble backoff timer may be reset if the UE re-initiates a new RA procedure.

In one implementation, the DL beam (e.g., SSB or CSI-RS) may be re-selected during the new RA procedure. In another implementation, the DL beam (e.g., SSB or CSI-RS) may not be re-selected during the new RA procedure.

Case 2-3: UE deactivates the panel and performs the random access resource selection procedure

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #1) that is used for the random access procedure (e.g., used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #1) and perform the random access resource selection procedure via another activated panel (e.g., the panel #2) or a default panel.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #2) that is not used for the random access procedure (e.g., not used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #2) and continue with the random access procedure without impact.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to activate a panel (e.g., panel #3) , that is originally deactivated the UE may activate the panel (e.g., panel #3) and continue with the random access procedure without impact. In one implementation, the UE may use one or more of the activated panels (e.g., panel #1 and/or panel #3) for transmission during the ongoing random access procedure.

In one implementation, the random access resource selection procedure may be the first step of the RA procedure.

In one implementation, the UE is performing the next attempt of the RA procedure when the UE performs the random access resource selection procedure. That is, in the implementations in Case 2-3, the UE may perform random access resource selection in the same RA procedure, rather than initiating a new random access procedure.

In one implementation, the UE may consider the RAR and/or contention resolution of the RA procedure is received unsuccessfully.

In one implementation, the Msg3 buffer may not be flushed.

In one implementation, the preamble transmission counter may not be reset. The preamble transmission counter may be incremented in one implementation and may not be incremented in another implementation.

In one implementation, the preamble power ramping counter may not be reset. The preamble power ramping counter may be incremented in one implementation and may not be incremented in another implementation.

In one implementation, the preamble backoff timer may not be reset.

In one implementation, the DL beam (e.g., SSB or CSI-RS) may be re-selected during the RA procedure. In another implementation, the DL beam (e.g., SSB or CSI-RS) may not be re-selected during the RA procedure.

Case 2-4: UE deactivates the panel and stops the RA procedure

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #1) that is used for the random access procedure (e.g., used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #1) and stop the random access procedure.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #2) that is not used for the random access procedure (e.g., not used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #2) and not stop the random access procedure.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to activate a panel (e.g., panel #3) that is originally deactivated, the UE may activate the panel (panel #3) and not stop the random access procedure. In one implementation, the UE may use one or more of the activated panels (e.g., panel #1 and/or panel #3) for transmission during the ongoing random access procedure.

In one implementation, the UE may re-initiate a new RA procedure via another activated panel or a default panel after the UE stops the RA procedure.

In one implementation, the UE may trigger a beam failure recovery procedure via another activated panel or a default panel after the UE stops the RA procedure.

In one implementation, UE may consider this as RA failure and perform cell re-selection. The UE may record the situation and report the failure (e.g., including a failure cause) and corresponding cell to the NW after RRC re-establishment.

Case 2-5: UE deactivates the panel and indicates RA problem to higher layer

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #1) that is used for the random access procedure (e.g., used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #1) and a MAC entity of the UE may indicate an RA problem to a higher layer (e.g., RRC layer) .

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate a panel (e.g., panel #2) that is not used for the random access procedure (e.g., not used for the transmission during the random access procedure , the UE may deactivate the panel (e.g., panel #2) and the MAC entity of the UE may not indicate an RA problem to a higher layer.

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to activate a panel (e.g., panel #3) that is originally deactivated , the UE may activate the panel (e.g., panel #3) and the MAC entity of the UE may not indicate an RA problem to a higher layer. In one implementation, the UE may use one or more of the activated panels (e.g., panel #1 and/or panel #3) for transmission during the ongoing random access procedure.

In one implementation, the UE may continue the RA procedure.

Case 2-6: UE deactivates the panel and triggers a beam failure recovery procedure

In one implementation, when the UE receives an indication from NW during a random access procedure, wherein the indication is to deactivate the a panel (e.g., panel #1) that is used for the random access procedure (e.g., used for the transmission during the random access procedure) , the UE may deactivate the panel (e.g., panel #1) and triggers a BFR procedure.

In one implementation, the UE may use another activated panel (e.g., panel #2) or a default panel to perform the BFR procedure.

In one implementation, the UE may stop the original RA procedure. In one implementation, the UE may stop the original RA procedure and initiate a new RA procedure for BFR.

Case 2-7: NW does not deactivate a panel of a UE if the UE is using the panel for RA procedure (e.g., for the transmission during the random access procedure)

In one implementation, the NW is not allowed to deactivate a panel during a RA procedure if the UE is using the panel (e.g., panel #1) to perform the RA procedure. In one implementation, when the NW performs CFRA (e.g., NW is providing a PDCCH order) , the NW may signal a dedicated panel together with the PDCCH order to indicate to the UE which panel is to be used for the CFRA transmission (e.g., preamble transmission) . The dedicated panel may be activated or deactivated according to a previous panel state configuration. In one implementation, the NW may signal a dedicated panel via a handover configuration (e.g., ReconfigurationWithSync) or a BFR configuration (e.g., BeamFailureRecoveryConfig) to the UE, such that the UE performs a specific RA procedure by using the dedicated panel.

In one implementation, the NW is allowed to deactivate a panel (e.g., panel #2) that is not used for a RA procedure (e.g., not used for the transmission during the random access procedure) .

In one implementation, the NW is allowed to activate a panel (e.g., panel #3) that is not used for a RA procedure (e.g., not used for the transmission during the random access procedure) .

The RA procedure in Case 2-7 may be a CFRA procedure. The RA procedure in Case 2-7 may be triggered by the NW.

Case 3: panel switching indication during an RA procedure

When a UE is performing a RA procedure via a first panel, the UE may receive an indication from network during the RA procedure to switch the first panel to a second panel for UL transmission. However, there may be some impacts when the UE changes the panel (for PRACH transmission) during the RA procedure.

One possible impact is that different panels may have different power control. For example, the UE may use different power via different panels for UL transmission. In an RA procedure, if an attempt of the RA procedure fails, the reason may be UL transmission power is not sufficient. Thus, for each attempt of the RA procedure, the UE may ramp up the power (e.g., by incrementing a preamble power ramping counter) to transmit the preamble. However, if the panel for PRACH transmission is switched during the RA procedure, some impacts related to power control may be expected due to different power control per panel.

Another possible impact is that different panels may have different timing control. For example, a timing advance parameter NTA and/or a timing advance offset may be provided per panel. In the RA procedure, the NW may estimate the timing advance of a panel based on preamble transmission. Therefore, the NW may provide a suitable timing advance value via RAR to the UE. However, if the panel for PRACH transmission is switched during the RA procedure, some impact related to timing advance may be expected due to different timing control per panel.

Referring to the upper part of Fig. 5, UE 510 uses panel #1 522 to perform an RA procedure (e.g., to perform preamble/PRACH transmission) . UE 510 may receive an indication from NW during the RA procedure (at any time during the RA procedure) to switch panel #1 522 to panel #2 524 to perform the RA procedure. In one implementation, panel #1 522 may be used for a first attempt of the RA procedure, and panel #2 524 may be used for a second attempt of the RA procedure. Panel #1 522 and panel #2 524 may be activated panels. In one implementation, the panel switching indication may be transmitted via a Msg2 and/or Msg4 of the random access procedure from NW. In one implementation, the panel switching indication may be a specific indication instead of being transmitted via the Msg2 and/or Msg4. Referring to Fig. 1A, the panel switching indication during the RA procedure may be transmitted in action 134, in action 138, or any time after action 132 (e.g., between action 132 and action 134) . Referring to Fig. 1B, the panel switching indication during the RA procedure may be transmitted in action 144 or any time after action 142 (e.g., between action 142 and action 144) . Referring to Fig. 2, for the two-step RA procedure, the panel switching indication during the RA procedure may be transmitted in action 234 or any time after action 232 (e.g., between action 232 and action 234) .

When the UE receives an indication from NW to switch the first panel (e.g., panel #1) to the second panel (e.g., panel #2) during a random access procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) , the UE may perform one or more of the following actions. If the UE performs multiple actions below, the order for performing the actions is not limited.

Case 3-1: UE does not switch the panel

In one implementation, the UE is using the first panel (e.g., panel #1) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) then the UE receives the indication from NW during the RA procedure, wherein the indication indicates to the UE to switch the first panel (e.g., panel #1) to the second panel (e.g., panel #2) . When receiving the indication, the UE may not follow the indication to switch the panel. In one implementation, the UE may ignore the indication.

In one implementation, the UE may continue using the first panel (e.g., panel #1) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) .

Case 3-2: UE switches the panel and continues with the ongoing RA procedure

In one implementation, the UE is using the first panel (e.g., panel #1) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure, then the UE receives the indication from NW during the RA procedure, wherein the indication indicates to the UE to switch the first panel (e.g., panel #1) to the second panel (e.g., panel #2) . After receiving the indication, the UE may switch from the first panel (e.g., panel #1) to the second panel (e.g., panel #2) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) and continue with the ongoing RA procedure.

In one implementation, the UE may apply the indication and continue with the ongoing RA procedure

In one implementation, the UE may switch the panel and continue with the ongoing RA procedure if the UE has received the RAR.

Case 3-3: UE switches the panel and re-initiates a new RA procedure

In one implementation, the UE is using the first panel (e.g., panel #1) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) , then the UE receives the indication from NW during the RA procedure, wherein the indication indicates the UE to switch the first panel (e.g., panel #1) to the second panel (e.g., panel #2) . After receiving the indication, the UE may stop the ongoing RA procedure and then re-initiate a new RA procedure. For example, the UE may perform random access procedure initialization.

In one implementation, the UE may use the second panel (e.g., panel #2) to perform the new RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) .

In one implementation, the Msg3 buffer may be flushed.

In one implementation, the preamble transmission counter may be reset.

In one implementation, the preamble power ramping counter may be reset.

In one implementation, the preamble backoff timer may be reset.

Case 3-4: UE switches the panel and performs the random access resource selection procedure

In one implementation, the UE is using the first panel (e.g., panel #1) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) , then the UE receives the indication from NW during the RA procedure, wherein the indication indicates to the UE to switch the first panel (e.g., panel #1) to the second panel (e.g., panel #2) . After receiving the indication, the UE may switch the first panel to the second panel and perform the random access resource selection procedure (immediately) via the second panel (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) .

In one implementation, the UE is performing the next attempt of the RA procedure when the UE performs the random access resource selection procedure. That is, in the implementations in Case 3-4, the UE may perform random access resource selection in the same RA procedure, rather than initiating a new random access procedure.

In one implementation, the Msg3 buffer may not be flushed.

In one implementation, the preamble transmission counter may not be reset. In one implementation, the preamble transmission counter may be incremented. In another implementation, the preamble transmission counter may not be incremented.

In one implementation, the preamble power ramping counter may not be reset. In one implementation, the preamble power ramping counter may be incremented. In another implementation, the preamble power ramping counter may not be incremented.

In one implementation, the preamble backoff timer may not be reset.

Case 3-5: UE switches the panel, and triggers a beam failure recovery procedure

In one implementation, the UE is using the first panel (e.g., panel #1) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) , then the UE receives the indication from NW during the RA procedure, wherein the indication indicates to the UE to switch the first panel (e.g., panel #1) to the second panel (e.g., panel #2) . After receiving the indication, the UE may switch the first panel to the second panel and trigger a BFR procedure.

In one implementation, the UE may use the second panel (e.g., panel #2) to perform the BFR procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the BFR procedure) .

In one implementation, the UE may initiate a new RA procedure for the BFR procedure, and the UE may use the second panel to perform preamble/PRACH transmission and/or other transmission during the new RA procedure.

In one implementation, the UE may stop the original RA procedure.

Case 3-6: NW does not switch a panel of a UE if the UE is performing an RA procedure via the panel

In one implementation, the NW is not allowed to switch a panel during an RA procedure if the UE is using the panel (e.g., panel #1) to perform the RA procedure (e.g., to perform preamble/PRACH transmission and/or other transmission during the RA procedure) .

If the UE activates/deactivates/switches the panel during a RA procedure, the UE may or may not ignore the received timing advance command (e.g., included in RAR) .

In one implementation, the UE may ignore the received timing advance command. For example, if the random access preamble was selected by the MAC entity among the contention-based random access preamble and the time alignment timer is running, the UE may ignore the received timing advance command. Because the TA included in the RAR is calculated based on the measurement of Msg1 transmission, the precision may not be better than the maintained TA. Thus, the UE may apply the maintained TA (e.g., NTA) instead of applying the TA from RAR.

However, if the UE switches the panel during the RA procedure, the TA for different panels may be different. The UE may re-initiate a new RA procedure or perform random access resource selection procedure again. In this case, the UE may not ignore the received timing advance command in the new RA procedure or the next attempt of the RA procedure. The UE may apply the timing advance command included in the RAR of the new RA procedure or of the next attempt of the RA procedure.

Alternatively, if the UE has not performed the next attempt of the RA procedure, the UE may ignore the received timing advance command. The UE may not apply the timing advance command included in the RAR of the RA procedure.

In one implementation, when the UE initiates the RA procedure (in RRC Connected state) , the panel activation/deactivation configuration may be suspended (e.g., the configuration may still be valid, but the UE does not follow the configuration during the RA procedure) . Consequently, the UE may use all panels to perform the RA procedure and the panel activation/deactivation configuration may resume after the RA procedure is completed. In one implementation, when the UE receives an indication from a base station to change the panel activation/deactivation state, the UE may update the configuration accordingly and apply the configuration after the RA procedure is successfully completed. In one implementation, during the RA procedure, the UE may use any panel, e.g., by UE implementation, to attempt the RA procedure.

In one implementation, when the UE initiates an RA procedure, the configuration or indication for panel activation/deactivation or panel switch may be released or discarded. The UE may not apply any configuration or indication for panel activation/deactivation or panel switch during the RA procedure.

Implementations disclosed below may be applied to any implementation, action, example or embodiment mentioned above:

In one implementation, if the UE uses a new panel for the RA procedure (e.g., used for the transmission during the RA procedure) , the UE may apply the configuration (for panel) for the new panel (instead of applying the configuration for the original panel) .

In one implementation, the indication for panel switch may be used to switch the panel for any UL transmission (e.g., PRACH, PUCCH, PUSCH, SRS transmission, etc. )

In one implementation, the RA procedure may be a CFRA, CBRA, and/or RA for BFR, etc.

In one implementation, when the UE receives an indication, the UE may trigger a confirmation message or MAC CE (e.g., MAC CE in a fixed size of zero bits) . The confirmation message may let the NW know the UE has successfully received the indication (e.g., the indication may be used to activate/deactivate/switch UE panel) . In one implementation, the confirmation message may be triggered or transmitted when (or after) the UE receives the indication. The confirmation message may be triggered or transmitted when (or after) the UE activates, deactivates, or switches the indicated panel.

Case 4: default panel

In one implementation, the default panel may be a panel that cannot be deactivated. The default panel may be used for initial access. The default panel may be used if the UE has not been indicated which panel is used for transmission. The default panel may be used if the currently used or indicated panel is deactivated. The default panel may be used for RA procedure (e.g., used for the transmission during the RA procedure) .

In one implementation, the default panel may be configured by RRC signaling. During the RRC configuration via UE specific downlink RRC message (e.g., a dedicated signaling) by a base station (e.g., a gNB) , the UE may be indicated with a default (set of) panel or a specific (set of) panel. The default panel or the specific panel may be applied for uplink and/or downlink (transmission) corresponding to a specific layer’s procedure (e.g., RA procedure) . For example, the UE may apply the default (set of) panel or the specific panel for Msg1, Msg2, Msg3, and/or Msg4 transmission of the RA procedure. In one implementation, the default panel or the specific panel may be configured as activated or deactivated in the RRC (re-) configuration. In one implementation, the default panel or the specific panel may be activated by the UE while the specific layer’s procedure is triggered. In one implementation, the default panel or the specific panel may be kept as activated until the UE receives explicitly downlink signaling that indicates deactivation. In one implementation, the default panel or the specific panel may be deactivated neither by the gNB nor the UE. In one implementation, the gNB may apply different (format of) signaling between (de) activation of the default/specific panel and (de) activation of the non-default/non-specific panel.

If the MAC entity receives a PDCCH/indication for panel switching (for a TRP, a serving Cell or a BWP) while a Random Access procedure (associated with that Serving Cell) is ongoing in the MAC entity, it may be up to UE implementation whether to switch panel or ignore the PDCCH/indication for panel switching, except for the PDCCH/indication reception for panel switching addressed to the C-RNTI for successful Random Access procedure completion in which case the UE may perform panel switching indicated by the PDCCH/indication. Upon reception of the PDCCH/indication for panel switching other than successful contention resolution, if the MAC entity decides to perform panel switching, the MAC entity may stop the ongoing Random Access procedure and initiate a Random Access procedure after performing the panel switching; if the MAC decides to ignore the PDCCH/indication for panel switching, the MAC entity may continue with the ongoing Random Access procedure (on the Serving Cell) .

Fig. 6 is a flowchart of a method 600 for antenna panel control according to an example implementation of the present disclosure. In action 602, the UE initiates an RA procedure. The RA procedure may be CBRA shown in Fig. 1A, CFRA shown in Fig. 1B, or two-step RA shown in Fig. 2. The UE may be equipped with a plurality of antenna panels, including a first antenna panel (e.g., panel #1) and a second antenna panel (e.g., panel #2) .

In action 604, the UE performs transmission, via a first antenna panel of the plurality of antenna panels (e.g., panel #1) , during the RA procedure. For example, the UE may use the first antenna panel for PRACH preamble transmission.

In action 606, the UE receives, from a base station (BS) , an antenna panel control message during the RA procedure. The antenna panel control message indicates to the UE to change a state of the plurality of antenna panels. The antenna panel control message in action 606 may be a panel activation/deactivation indication in Case 2 or a panel switching indication in Case 3.

In one implementation, the antenna panel control message indicates to the UE to deactivate the first antennal panel (e.g., panel #1) . In one implementation, the antenna panel control message indicates to the UE to switch the first antennal panel (e.g., panel #1) to the second antennal panel (e.g., panel #2) for transmission.

In one implementation, the antenna panel control message is not received via a random access response (RAR) or via a signal for contention resolution of the RA procedure. For CBRA shown in Fig. 1A and CFRA shown in Fig. 1B, the antenna panel control message may be received between Msg1 and Msg2, between Msg2 and Msg3, between Msg3 and Msg4, or after Msg4. For two-step RACH shown in Fig. 2, the antenna panel control message may be received between MsgA and MsgB, or after MsgB.

In action 608, the UE ignores the antenna panel control message. Example implementations of action 608 may include, but not limited to, Case 2-1 and Case 3-1.

Fig. 7 is a flowchart of a method 700 for antenna panel control according to another example implementation of the present disclosure. In action 702, the UE initiates a first RA procedure. The first RA procedure may be CBRA shown in Fig. 1A, CFRA shown in Fig. 1B, or two-step RA shown in Fig. 2. The UE may be equipped with a plurality of antenna panels, including a first antenna panel (e.g., panel #1) and a second antenna panel (e.g., panel #2) .

In action 704, the UE performs transmission, via a first antenna panel of the plurality of antenna panels (e.g., panel #1) , during the first RA procedure. For example, the UE may use the first antenna panel for PRACH preamble transmission.

In action 706, the UE receives, from a BS, an antenna panel control message during the first RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels. The antenna panel control message in action 706 may be a panel activation/deactivation indication in Case 2 or a panel switching indication in Case 3.

In action 708, the UE stops the first RA procedure. In action 710, the UE initiates a second RA procedure. Example implementations of action 708 and action 710 may include, but not limited to, Case 2-2, Case 2-4 and Case 3-3.

In action 712, the UE performs transmission, via a second antenna panel of the plurality of antenna panels (e.g., panel #2) , during the second RA procedure.

In one implementation, the antenna panel control message indicates to the UE to deactivate the first antennal panel (e.g., panel #1) . In one implementation, the antenna panel control message indicates to the UE to activate the second antennal panel (e.g., panel #2) . In one implementation, the antenna panel control message indicates to the UE to switch the first antennal panel (e.g., panel #1) to the second antennal panel (e.g., panel #2) for transmission.

In one implementation, the second antennal panel may be a default panel that cannot be deactivated. Implementations related to the default panel may be referred to Case 4.

In one implementation, the UE may reset at least one of the following parameters: a preamble transmission counter, a preamble power ramping counter, and a preamble backoff timer, when stopping the first RA procedure and initiating the second RA procedure.

Fig. 8 is a block diagram illustrating a node 800 for wireless communication according to the present disclosure. As illustrated in Fig. 8, the node 800 may include a transceiver 820, a processor 828, a memory 834, one or more presentation components 838, and at least one antenna 836. The node 800 may also include an RF spectrum band module, a BS communications module, a network communications module, and a system communications management module, Input /Output (I/O) ports, I/O components, and a power supply (not shown) .

Each of the components may directly or indirectly communicate with each other over one or more buses 840. The node 800 may be a UE or a BS that performs various functions disclosed with reference to Figs. 1 through 7.

The transceiver 820 has a transmitter 822 (e.g., transmitting/transmission circuitry) and a receiver 824 (e.g., receiving/reception circuitry) and may be configured to transmit and/or receive time and/or frequency resource partitioning information. The transceiver 820 may be configured to transmit in different types of subframes and slots including but not limited to usable, non-usable and flexibly usable subframes and slot formats. The transceiver 820 may be configured to receive data and control channels.

The node 800 may include a variety of computer-readable media. Computer-readable media may be any available media that may be accessed by the node 800 and include both volatile and non-volatile media, removable and non-removable media.

The computer-readable media may include computer storage media and communication media. Computer storage media include both volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules or data.

Computer storage media include RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices. Computer storage media do not include a propagated data signal. Communication media typically embody computer-readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and include any information delivery media.

The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Communication media include wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the previously listed components should also be included within the scope of computer-readable media.

The memory 834 may include computer-storage media in the form of volatile and/or non-volatile memory. The memory 834 may be removable, non-removable, or a combination thereof.

Example memory includes solid-state memory, hard drives, optical-disc drives, etc. As illustrated in Fig. 8, the memory 834 may store computer-readable, computer-executable instructions 832 (e.g., software codes) that are configured to cause the processor 828 to perform various disclosed functions with reference to Figs. 1 through 7. Alternatively, the instructions 832 may not be directly executable by the processor 828 but be configured to cause the node 800 (e.g., when compiled and executed) to perform various functions disclosed herein.

The processor 828 (e.g., having processing circuitry) may include an intelligent hardware device, e.g., a Central Processing Unit (CPU) , a microcontroller, an ASIC, etc. The processor 828 may include memory.

The processor 828 may process the data 830 and the instructions 832 received from the memory 834, and information transmitted and received via the transceiver 820, the base band communications module, and/or the network communications module. The processor 828 may also process information to be sent to the transceiver 820 for transmission via the antenna 836 to the network communications module for transmission to a core network.

One or more presentation components 838 present data to a person or another device. Examples of presentation components 838 include a display device, a speaker, a printing component, and a vibrating component.

In view of the present disclosure, it is obvious that various techniques may be used for implementing the concepts in the present disclosure without departing from the scope of those concepts. Moreover, while the concepts have been disclosed with specific reference to certain implementations, a person of ordinary skill in the art may recognize that changes may be made in form and detail without departing from the scope of those concepts.

As such, the described implementations are to be considered in all respects as illustrative and not restrictive. It should also be understood that the present disclosure is not limited to the particular implementations disclosed and many rearrangements, modifications, and substitutions are possible without departing from the scope of the present disclosure.

Claims

A method for antenna panel control performed by a user equipment (UE) , the UE including a plurality of antenna panels, the method comprising:

initiating a random access (RA) procedure;

performing transmission, via a first antenna panel of the plurality of antenna panels, during the RA procedure;

receiving, from a base station (BS) , an antenna panel control message during the RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels; and

ignoring the antenna panel control message.
The method of claim 1, wherein the antenna panel control message indicates to the UE to deactivate the first antennal panel.
The method of claim 1, wherein the antenna panel control message indicates to the UE to switch the first antennal panel to a second antennal panel of the plurality of antenna panels for transmission.
The method of claim 1, wherein the antenna panel control message is not received via a random access response (RAR) or via a signal for contention resolution of the RA procedure.
A method for antenna panel control performed by a user equipment (UE) , the UE including a plurality of antenna panels, the method comprising:

initiating a first random access (RA) procedure;

performing transmission, via a first antenna panel of the plurality of antenna panels, during the first RA procedure;

receiving, from a base station (BS) , an antenna panel control message during the first RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels;

stopping the first RA procedure;

initiating a second RA procedure; and

performing transmission, via a second antenna panel of the plurality of antenna panels, during the second RA procedure.
The method of claim 5, wherein the antenna panel control message indicates to the UE to deactivate the first antennal panel.
The method of claim 5, wherein the antenna panel control message indicates to the UE to activate the second antennal panel.
The method of claim 5, wherein the antenna panel control message indicates to the UE to switch the first antenna panel to the second antenna panel for transmission.
The method of claim 5, wherein the second antenna panel is a default panel that cannot be deactivated.
The method of claim 5, further comprising:

resetting at least one of the following parameters: a preamble transmission counter, a preamble power ramping counter, and a preamble backoff timer.
A user equipment (UE) comprising:

a plurality of antenna panels;

one or more non-transitory computer-readable media containing computer-executable instructions embodied therein; and

at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor configured to execute the computer-executable instructions to:

initiate a random access (RA) procedure;

perform transmission, via a first antenna panel of the plurality of antenna panels, during the RA procedure;

receive, from a base station (BS) , an antenna panel control message during the RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels; and

ignore the antenna panel control message.
The UE of claim 11, wherein the antenna panel control message indicates to the UE to deactivate the first antennal panel.
The UE of claim 11, wherein the antenna panel control message indicates to the UE to switch the first antennal panel to a second antennal panel of the plurality of antenna panels for transmission.
The UE of claim 11, wherein the antenna panel control message is not received via a random access response (RAR) or via a signal for contention resolution of the RA procedure.
A user equipment (UE) comprising:

a plurality of antenna panels;

one or more non-transitory computer-readable media containing computer-executable instructions embodied therein; and

at least one processor coupled to the one or more non-transitory computer-readable media, the at least one processor configured to execute the computer-executable instructions to:

initiate a first random access (RA) procedure;

perform transmission, via a first antenna panel of the plurality of antenna panels, during the first RA procedure;

receive, from a base station (BS) , an antenna panel control message during the first RA procedure, the antenna panel control message indicating to the UE to change a state of the plurality of antenna panels;

stop the first RA procedure;

initiate a second RA procedure; and

perform transmission, via a second antenna panel of the plurality of antenna panels, during the second RA procedure.
The UE of claim 15, wherein the antenna panel control message indicates to the UE to deactivate the first antennal panel.
The UE of claim 15, wherein the antenna panel control message indicates to the UE to activate the second antennal panel.
The UE of claim 15, wherein the antenna panel control message indicates to the UE to switch the first antenna panel to the second antenna panel for transmission.
The UE of claim 15, wherein the second antenna panel is a default panel that cannot be deactivated.
The UE of claim 15, wherein the at least one processor is further configured to execute the computer-executable instructions to:

reset at least one of the following parameters: a preamble transmission counter, a preamble power ramping counter, and a preamble backoff timer.