Random access procedure using the secondary cell downlink channel

Abstract

Aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may determine to initiate a random access procedure for a primary cell; and receive at least one physical downlink control channel communication on a secondary cell of the primary cell, the communication conveying information associated with the random access procedure for the primary cell. Numerous other aspects are provided.

Description

Technical Field

[0001] Broadly speaking, aspects of the present disclosure relate to wireless communication, and more particularly, aspects of the present disclosure relate to techniques and apparatuses for using a random access procedure for a secondary cell downlink channel. Background Art

[0002] Wireless communication systems have been widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ a multiple access technology that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems, Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE / Advanced LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0003] A wireless communication network may include multiple Base Stations (BSs), where a BS is capable of supporting communication with multiple User Equipments (UEs). A User Equipment (UE) may communicate with a Base Station (BS) via a downlink and an uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As described in further detail herein, a BS may refer to a Node B, a gNB, an Access Point (AP), a radio head, a Transmission and Reception Point (TRP), a New Radio (NR) BS, a 5G Node B, and so on.

[0004] The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipments to communicate over urban, national, regional, or even global scales. New Radio (NR), which may also be referred to as 5G, is an evolved set of the LTE mobile standard released by the 3rd Generation Partnership Project (3GPP). NR is designed to better support mobile broadband Internet access by improving spectral efficiency, reducing cost, enhancing services, making full use of new spectrums, using orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also referred to as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple-input multiple-output (MIMO) antenna technologies, and carrier aggregation. However, with the continuous increase in the demand for mobile broadband access, there is a need to further improve LTE and NR technologies. Preferably, these improvements should also be applicable to other multiple access technologies and telecommunication standards that adopt these technologies. SUMMARY OF THE INVENTION

[0005] In some aspects, a method for wireless communication performed by a user equipment (UE) may include: determining to initiate a random access procedure for a primary cell; and receiving at least one physical downlink control channel (PDCCH) communication on a secondary cell of the primary cell, the PDCCH communication carrying information associated with the random access procedure for the primary cell.

[0006] In some aspects, a UE for wireless communication may include a memory and one or more processors operatively coupled to the memory. The memory and the one or more processors may be configured to: determine to initiate a random access procedure for a primary cell; and receive at least one PDCCH communication on a secondary cell of the primary cell, the PDCCH communication carrying information associated with the random access procedure for the primary cell.

[0007] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When the one or more instructions are executed by one or more processors of a UE, the one or more processors may be caused to: determine to initiate a random access procedure for a primary cell; and receive at least one PDCCH communication on a secondary cell of the primary cell, the PDCCH communication carrying information associated with the random access procedure for the primary cell.

[0008] In some aspects, an apparatus for wireless communication may include: a unit for determining to initiate a random access procedure for a primary cell; a unit for receiving at least one PDCCH communication on a secondary cell of the primary cell, the PDCCH communication transmitting information associated with the random access procedure for the primary cell.

[0009] Aspects of the present disclosure generally include methods, apparatuses, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and / or processing systems, as fully described herein with reference to the figures and the specification and as illustrated in the figures and the specification.

[0010] To better understand the following detailed description, the above has provided a rather general overview of the features and technical advantages of examples according to the present disclosure. Additional features and advantages will be described below. The disclosed concepts and specific examples can be readily used as a basis for modifying or designing other structures for the same purpose of implementing the present disclosure. These equivalent constructs do not depart from the scope of the appended claims. When considering the following detailed description in conjunction with the figures, the characteristics (regarding their organization and operation methods) of the concepts disclosed herein, as well as the associated advantages, will be better understood. Each of these figures is provided for illustrative and descriptive purposes only and is not used as a limitation of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] To understand in detail the features described above of the present disclosure, the present application gives a more specific description with reference to some aspects for the above brief summary, some of which are illustrated in the figures. However, it should be noted that since the description of the present invention allows other equivalent effective aspects, these figures only depict some typical aspects of the present disclosure and should not be considered as limiting the scope of protection of the present invention. The same reference numerals in different figures may identify the same or similar elements.

[0012] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network according to various aspects of the present disclosure.

[0013] Figure 2 is a block diagram conceptually illustrating an example of communication between a base station and a UE in a wireless communication network according to various aspects of the present disclosure.

[0014] Figure 3A and Figure 3B are diagrams showing examples of a random access procedure using a secondary cell downlink channel according to various aspects of the present disclosure.

[0015] Figure 4FIG. is a diagram showing an exemplary process performed, for example, by a user equipment, in accordance with various aspects of the present disclosure. DETAILED DESCRIPTION

[0016] Aspects of the present disclosure are described more fully hereinafter with reference to the accompanying drawings. However, the present disclosure may be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those of ordinary skill in the art. Based on the present application, those of ordinary skill in the art should understand that the scope of the present disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently or in combination with any other aspect of the present disclosure. For example, a device may be implemented using any number of the aspects set forth herein, or a method may be implemented. Further, the scope of the present disclosure is intended to cover such a device or method that may be implemented using other structures, functions, or structures and functions different from those set forth in the aspects of the present disclosure herein, or structures and functions different from those set forth in the aspects of the present disclosure herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more components of the present invention.

[0017] Some aspects of a telecommunications system are now presented with reference to various devices and techniques. These devices and techniques will be described in the following detailed description and depicted in the drawings by various boxes, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using hardware, software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system.

[0018] It should be noted that although terms typically associated with 3G and / or 4G wireless technologies are used herein to describe aspects herein, aspects of the present disclosure may also be applied to communication systems based on other generations (e.g., 5G and later, which includes NR technology).

[0019] Figure 1FIG. 0 is a diagram illustrating a wireless network 100 that can implement aspects of the present disclosure. The wireless network 100 can be an LTE network or some other wireless network (e.g., a 5G or NR network). The wireless network 100 can include multiple BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with user equipment (UE), and a BS can also be referred to as a base station, NR BS, Node B, gNB, 5G Node B (NB), access point, transmission reception point (TRP), etc. Each BS can provide communication coverage for a specific geographical area. In 3GPP, depending on the context in which the term "cell" is used, the term "cell" can refer to the coverage area of a BS and / or the BS subsystem serving that coverage area.

[0020] A BS can provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell can cover a relatively large geographical area (e.g., with a radius of several kilometers), which allows UEs with service subscriptions to access without restriction. A pico cell can cover a relatively small geographical area, which allows UEs with service subscriptions to access without restriction. A femto cell can cover a relatively small geographical area (e.g., a home), which allows UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)) to have restricted access. A BS for a macro cell can be called a macro BS. A BS for a pico cell can be called a pico BS. A BS for a femto cell can be called a femto BS or a home BS. In Figure 1 the example shown, BS 110a can be a macro BS for macro cell 102a, BS 110b can be a pico BS for pico cell 102b, and BS 110c can be a femto BS for femto cell 102c. A BS can support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "Node B", "5G NB", and "cell" can be used interchangeably.

[0021] In some aspects, a cell does not need to be stationary, and the geographical area of a cell can move according to the location of a mobile BS. In some aspects, a BS can use any suitable transport network to interconnect with each other and / or interconnect to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces (e.g., direct physical connections, virtual networks, etc.).

[0022] The wireless network 100 may also include relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send the transmission of the data to a downstream station (e.g., a UE or a BS). A relay station can also be a UE that can relay transmissions of other UEs. In Figure 1 In the example shown, the relay station 110d can communicate with the macro BS 110a and the UE 120d to facilitate communication between the BS 110a and the UE 120d. A relay station can also be referred to as a relay BS, a relay base station, a repeater, etc.

[0023] The wireless network 100 can be a heterogeneous network that includes different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.). These different types of BSs can have different transmit power levels, different coverage areas, and different impacts on interference in the wireless network 100. For example, a macro BS can have a relatively high transmit power level (e.g., 5 to 40 watts), while pico BSs, femto BSs, and relay BSs can have relatively low transmit power levels (e.g., 0.1 to 2 watts).

[0024] The network controller 130 can be coupled to a set of BSs and provide coordination and control for these BSs. The network controller 130 can communicate with these BSs via a backhaul. These BSs can also communicate with each other, e.g., directly or indirectly via a wireless backhaul or a wired backhaul.

[0025] UEs 120 (e.g., 120a, 120b, 120c) can be dispersed throughout the wireless network 100, and each UE can be stationary or mobile. A UE can also be referred to as an access terminal, a terminal, a mobile station, a user unit, a station, etc. A UE can be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet device, a camera, a gaming device, a netbook, a smartbook, a superbook, a medical device or equipment, a biosensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio device), a vehicle component or sensor, a smart meter / sensor, an industrial manufacturing device, a global positioning system device, or any other suitable device configured to communicate via a wireless medium or a wired medium.

[0026] Some UEs can be regarded as Machine Type Communication (MTC) UEs or evolved or enhanced Machine Type Communication (eMTC) UEs. For example, MTC and eMTC UEs include robots, drones, remote devices, sensors, meters, monitors, location tags, etc. that can communicate with a base station, another device (e.g., a remote device), or some other entity. For example, a wireless node can provide a connection to or from a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs can be considered Internet of Things (IoT) devices and / or can be implemented as NarrowBand IoT (NB-IoT) devices. Some UEs can be considered Customer Premises Equipment (CPE). The UE 120 can be included in a housing that houses the components of the UE 120 (e.g., a processor component, a memory component, etc.).

[0027] Generally, in a given geographical area, any number of wireless networks can be deployed. Each wireless network can support a specific Radio Access Technology (RAT) and can operate on one or more frequencies. The RAT can also be referred to as a radio technology, an air interface, etc. The frequency can also be referred to as a carrier, a frequency channel, etc. Each frequency can support a single RAT in a given geographical area to avoid interference between wireless networks of different RATs. In some cases, an NR or 5G RAT network can be deployed.

[0028] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) can communicate directly using one or more sidelink channels (e.g., communicate with each other without using the base station 110 as an intermediate device). For example, the UE 120 can communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocols (e.g., which can include vehicle-to-vehicle (V2V) protocols, vehicle-to-infrastructure (V2I) protocols, etc.), a mesh network, etc. In this case, the UE 120 can perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein that are performed by the base station 110.

[0029] As indicated above, Figure 1 is provided as an example. Other examples can be different from the examples described with reference to Figure 1 the examples described above.

[0030] Figure 2 A block diagram 200 of a design solution 200 of the base station 110 and the UE 120 is shown, where the base station 110 and the UE 120 can be one of the base stations in Figure 1 and Figure 1One of the UEs in. The base station 110 may be equipped with T transmit antennas 234a to 234t, and the UE 120 may be equipped with R receive antennas 252a to 252r, where generally T≥1 and R≥1.

[0031] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCSs) for the UE at least in part based on the channel quality indicator (CQI) received from each UE, process (e.g., encode and modulate) the data for the UE at least in part based on the MCS selected for each UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRSs)) and synchronization signals (e.g., primary synchronization signal (PSS) and secondary synchronization signal (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on these data symbols, control symbols, overhead symbols, and / or reference symbols (if any), and provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to an analog signal, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T transmit antennas 234a to 234t, respectively. According to various aspects described in further detail below, position coding may be utilized to generate synchronization signals to convey other information.

[0032] At the UE 120, antennas 252a through 252r may receive downlink signals from the base station 110 and / or other base stations and may provide the received signals to demodulators (DEMOD) 254a through 254r. Each demodulator 254 may condition (e.g., filter, amplify, down-convert, and digitize) the respective received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. The MIMO detector 256 may obtain the received symbols from all R demodulators 254a through 254r, perform MIMO detection (if any) on the received symbols, and provide detected symbols. The receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for the UE 120 to the data sink 260, and provide decoded control information and system information to the controller / processor 280. The channel processor may determine a reference signal received power (RSRP), a received signal strength indicator (RSSI), a reference signal received quality (RSRQ), a channel quality indicator (CQI), etc. In some aspects, one or more components of the UE 120 may be included in a housing.

[0033] On the uplink, at the UE 120, the transmit processor 264 may receive data from the data source 262, receive control information (e.g., for reporting including RSRP, RSSI, RSRQ, CQI, etc.) from the controller / processor 280, and process the data and control information. The transmit processor 264 may also generate reference symbols for one or more reference signals. Symbols from the transmit processor 264 may be precoded (if any) by the TX MIMO processor 266, further processed (e.g., for DFT-s-OFDM, CP-OFDM, etc.) by the modulators 254a through 254r, and sent back to the base station 110. At the base station 110, uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 232, detected (if any) by the MIMO detector 236, and further processed by the receive processor 238 to obtain decoded data and control information sent by the UE 120. The receive processor 238 may provide the decoded data to the data sink 239 and the decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292.

[0034] Figure 2The controller / processor 240 of base station 110, the controller / processor 280 of UE 120, and / or any other component may perform one or more techniques associated with a random access procedure using a secondary cell downlink channel, as further described in detail elsewhere herein. For example, the controller / processor 240 of base station 110, the controller / processor 280 of UE 120, and / or Figure 2 any other component may perform or direct operations of, for example Figure 4 processing 400, and / or other processing as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, when the one or more instructions are executed by one or more processors of base station 110 and / or UE 120, operations of, for example Figure 4 processing 400, and / or other processing as described herein may be performed or directed. Scheduler 246 may schedule data transmissions of the UE on the downlink and / or uplink.

[0035] In some aspects, UE 120 may include: a unit for determining to initiate a random access procedure for a primary cell; a unit for receiving at least one physical downlink control channel (PDCCH) communication on a secondary cell of the primary cell, the PDCCH communication carrying information associated with the random access procedure for the primary cell, and so on. In some aspects, these units may include one or more components of UE 120 described in conjunction with Figure 2 for example, controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, and so on.

[0036] As indicated above, Figure 2 is provided as an example. Other examples may be different from the example described with reference to Figure 2

[0037] ​In some wireless communication systems, a UE may access multiple cells. For example, the UE may monitor communications on a primary cell, a secondary cell, a primary-secondary cell (e.g., among multiple secondary cells that the UE is configured to monitor), etc. The UE may receive a Physical Downlink Shared Channel (PDSCH) on the primary cell, or transmit a Physical Uplink Shared Channel (PUSCH) on the primary cell. In this case, a secondary cell may be configured as a scheduling cell for the primary cell. For example, the UE may monitor a Physical Downlink Control Channel (PDCCH) on the secondary cell. The UE may receive Downlink Control Information (DCI) on the secondary cell, which schedules, for example, the PDSCH or the PUSCH. A Random Access (RA) procedure may occur for the primary cell. However, in order for the RA procedure to occur for the primary cell, the UE may have to monitor the PDCCH on the primary cell to enable the RA procedure. As a result, the UE may use excessive processing resources, excessive power resources, and / or excessive network resources due to monitoring the PDCCH on both the primary cell and the secondary cell.

[0038] Some aspects described herein enable an RA procedure using a secondary cell downlink channel. For example, the UE may monitor and receive a PDCCH on the secondary cell, which may carry information associated with the RA procedure for the primary cell. In this way, the UE may avoid monitoring the PDCCH on both the primary cell and the secondary cell, thereby reducing the use of processing resources, power resources, and / or network resources.

[0039] Figure 3A and Figure 3B are diagrams of example 300 / 300' of an RA procedure using a secondary cell downlink channel, in accordance with various aspects of the present disclosure. As Figure 3A and Figure 3B shown, example 300 / 300' includes a BS 110 and a UE 120.

[0040] As Figure 3AAs further shown and by reference numeral 310, the UE 120 may initiate a RA procedure for a primary cell (PCell) or a primary-secondary cell (PSCell). For example, the UE 120 may determine to monitor the PDCCH on a secondary cell (SCell) to initiate data transmission for the primary cell, obtain timing information, obtain synchronization information, etc. In some aspects, the UE 120 may receive configuration information associated with configuring the monitoring of the PDCCH on the secondary cell. For example, the UE 120 may receive information identifying a common search space (CSS) (e.g., type 1 CSS) on the secondary cell, which is combined with a UE-specific search space (USS) for which cross-carrier scheduling will be monitored. In such a case, the UE 120 may monitor the type 1 CSS on the secondary cell to receive a PDSCH with a random access (RA) response (RAR) grant (e.g., downlink control information (DCI) type 1_0 with a cyclic redundancy check (CRC) scrambled at least in part based on a RA radio network temporary identifier (RA-RNTI)), a retransmission of a RAR-granted PUSCH (e.g., DCI type 0_0 with a CRC scrambled at least in part based on a cell RNTI (C-RNTI) or a temporary C-RNTI (TC-RNTI)), a scheduled PDSCH message type 4 (msg4) (e.g., DCI type 1_0 with a CRC scrambled at least in part based on a TC-RNTI), etc.

[0041] As Figure 3A As further shown and by reference numeral 320, the UE 120 may transmit signaling associated with the RA procedure. For example, the UE 120 may receive at least one PDCCH communication on the secondary cell to enable the RA procedure for the primary cell (or the primary-secondary cell). In some aspects, the UE 120 may receive or transmit at least one communication of the RA procedure on the primary cell. For example, the UE 120 may receive a physical random access channel (PRACH) and transmit a physical uplink control channel (PUCCH) on the primary cell in conjunction with the RA procedure. In such a case, as Figure 3A shown, the UE 120 may receive a PRACH transmission on the primary cell (or the primary-secondary cell), receive a PDCCH with DCI type 1_0 in the type 1 CSS and a corresponding scheduled RAR grant on the secondary cell, transmit a PUSCH scheduled by the RAR grant on the secondary cell, receive a PDCCH with DCI type 1_0 in the type 1 CSS and an associated msg4 PDSCH on the secondary cell, and may transmit a hybrid automatic repeat request (HARQ) acknowledgment (ACK) on the PUCCH on the primary cell (or the primary-secondary cell).

[0042] In some aspects, the UE 120 may determine the quasi - co - location (QCL) parameters for DCI type 1_0 received on a secondary cell in type 1 CSS (e.g., the DCI scheduling the PDSCH for the RAR grant). For example, the UE 120 may determine that the QCL parameters are the same as the QCL parameters for the synchronization signal (SS) / physical broadcast channel (PBCH) block. Additionally or alternatively, the UE 120 may determine that the QCL parameters are the same as the QCL parameters for the channel state information reference signal (CSI - RS) resource that the UE 120 uses for PRACH associated transmission. Additionally or alternatively, the UE 120 may determine the spatial domain filter, spatial domain relationship, and / or transmit or receive beam at least in part based on the QCL parameters for the SS / PBCH block, CSI - RS resource, combinations thereof, etc. In some aspects, the UE 120 may determine the QCL parameters independent of whether the QCL parameters are indicated by the transmission configuration indicator (TCI) state for a control resource set (CORESET) in which the UE 120 receives the PDCCH with DCI format type 1_0. Alternatively, the UE 120 may use the QCL parameters indicated by the TCI state for the CORESET in which the UE 120 receives the PDCCH with DCI format type 1_0. In some aspects, the UE 120 may determine the transform precoder for the PUSCH scheduled by the RAR grant (e.g., the PUSCH on the secondary cell). For example, the UE 120 may select the transform precoder in the random access channel (RACH) configuration common message (e.g., which is configured on the primary cell). Alternatively, the UE 120 may select the transform precoder configured on the secondary cell.

[0043] In contrast, as Figure 3B shown, the UE 120 may transmit the PUSCH scheduled by the RAR grant on the primary cell. For example, the UE 120 may transmit the PUSCH granted by the RAR on the primary cell at least in part based on the PUSCH being scheduled by the RAR grant on the secondary cell or the DCI format type 0_0 with a CRC scrambled by the TC - RNTI on the secondary cell. In some aspects, the UE 120 may determine the bandwidth part size for the PUSCH granted by the RAR for the secondary cell at least in part based on the frequency domain resource allocation indicator of the DCI format type 0_0. Additionally or alternatively, the UE 120 may determine the bandwidth part size for the PUSCH granted by the RAR for the primary cell at least in part based on the frequency domain resource allocation indicator of the DCI format type 0_0.

[0044] In some aspects, the UE 120 may receive a PDCCH to trigger a PUSCH retransmission of a RAR grant on the primary cell. For example, the UE 120 may monitor a type 1 CSS on a secondary cell to receive DCI format 1_0 that schedules a PDSCH for a RAR grant and a msg4 PDSCH, and may monitor a type 1 CSS on the primary cell to receive DCI format 0_0 (which schedules a retransmission of the PDSCH for a RAR grant). In this case, the UE 120 utilizes the resources of both cells to achieve efficient transmission and trigger the retransmission of the PDSCH for a RAR grant.

[0045] As indicated above, Figure 3A and Figure 3B are provided as examples. Other examples may be different from the examples Figure 3A and Figure 3B described with reference to

[0046] Figure 4 FIG. 400 is a diagram illustrating an exemplary process 400 performed, for example, by a UE, in accordance with various aspects of the present disclosure. Exemplary process 400 is an example of operations performed by a UE (e.g., UE 120, etc.) associated with a random access procedure using a secondary cell downlink channel.

[0047] As Figure 4 shown in FIG. 400, in some aspects, process 400 may include: determining to initiate a random access procedure for a primary cell (block 410). For example, the UE may (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) determine to initiate a random access procedure for a primary cell, as described above.

[0048] As Figure 4 further shown in FIG. 400, in some aspects, process 400 may include: receiving at least one PDCCH communication on a secondary cell of a primary cell, the PDCCH communication carrying information associated with a random access procedure for the primary cell (block 420). For example, the UE may (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) receive at least one PDCCH communication on a secondary cell of a primary cell, the PDCCH communication carrying information associated with a random access procedure for the primary cell, as described above.

[0049] Process 400 may include additional aspects, e.g., any single aspect or any combination of the aspects described below and / or aspects of one or more other processes described elsewhere herein.

[0050] In a first aspect, receiving the at least one PDCCH communication includes: monitoring a common search space on the secondary cell to receive the at least one PDCCH communication.

[0051] In a second aspect, either alone or in combination with the first aspect, the common search space is a type 1 CSS on which downlink control information with a cyclic redundancy check is received, and the cyclic redundancy check is scrambled at least in part based on a random access radio network temporary identifier or a temporary cell radio network temporary identifier.

[0052] In a third aspect, either alone or in combination with one or more of the first and second aspects, receiving the at least one PDCCH communication includes: monitoring a UE-specific search space configured for cross-carrier scheduling to receive the at least one PDCCH communication.

[0053] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, the at least one PDCCH communication includes at least one downlink control information message.

[0054] In a fifth aspect, either alone or in combination with one or more of the first to fourth aspects, the at least one PDCCH communication includes at least one of the following: a scheduled random access response physical downlink shared channel, a retransmission of a scheduled random access response grant for a physical uplink shared channel, or a scheduled message type 4 (msg4) physical downlink shared channel.

[0055] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, processing 400 includes: transmitting a physical random access channel communication or a physical uplink control channel communication on the primary cell, and transmitting a feedback message for the msg4 physical downlink shared channel communication.

[0056] In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the quasi-co-location (QCL) parameters of a control resource set (CORESET) of downlink control information on a type 1 CSS for scheduling a random access response physical downlink shared channel are at least in part based on resources associated with the physical random access channel communication, and the resources are at least one of the following: a synchronization signal resource, a physical broadcast channel block resource, or a channel state information reference signal resource.

[0057] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, the QCL parameter of the downlink control information for scheduling the random access response physical downlink shared channel on type 1 CSS is at least partially based on the transmission configuration indicator state of the control resource set associated with the communication of the at least one PDCCH.

[0058] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, the transform precoder of the physical uplink shared channel on the secondary cell scheduled by the random access response grant is at least partially based on the transform precoder in the random access channel message on the primary cell.

[0059] In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the transform precoder of the physical uplink shared channel on the secondary cell scheduled by the random access response grant is at least partially based on the transform precoder configured on the secondary cell.

[0060] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, the processing 400 includes: transmitting the physical uplink shared channel communication granted by the random access response on the primary cell.

[0061] In a twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, at least partially based on the random access response uplink grant or downlink control information message received on the secondary cell, transmitting the physical uplink shared channel communication granted by the random access response on the primary cell.

[0062] In a thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the frequency domain resource allocation of the downlink control information message is at least partially based on the bandwidth part size of the secondary cell or the primary cell.

[0063] In a fourteenth aspect, alone or in combination with one or more of the first to thirteenth aspects, the processing 400 includes: receiving a specific PDCCH communication on the primary cell to trigger a retransmission of the physical uplink shared channel granted by the random access response.

[0064] In a fifteenth aspect, alone or in combination with one or more of the first to fourteenth aspects, the processing 400 includes: monitoring type 1 CSS on the secondary cell and the primary cell to receive the at least one PDCCH communication and the specific PDCCH communication.

[0065] In a sixteenth aspect, either alone or in combination with one or more of the first to fifteenth aspects, the processing 400 includes: receiving, in the type 1 CSS on the secondary cell, at least one of the following: a scheduled random access response physical downlink shared channel (PDSCH) or a msg4 PDSCH.

[0066] In a seventeenth aspect, either alone or in combination with one or more of the first to sixteenth aspects, the processing 400 includes: receiving, in the type 1 CSS on the primary cell, a message scheduling a retransmission of a physical uplink shared channel for a random access response grant.

[0067] Although Figure 4 illustrative blocks of the processing 400 are shown, in some aspects, compared to Figure 4 those described in, the processing 400 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks. Additionally or alternatively, two or more of the blocks of the processing 400 may be executed in parallel.

[0068] The foregoing disclosure provides illustration and description, but is not exhaustive and does not limit these aspects to the precise forms disclosed. Modifications and variations can be made in light of the above disclosure, or can be obtained from practice of these aspects.

[0069] As used herein, the term "component" is intended to be broadly interpreted to include hardware, firmware, and / or a combination of hardware and software. As used herein, a processor is implemented using hardware, firmware, and / or a combination of hardware and software.

[0070] As used herein, depending on the context, meeting a threshold may refer to a value greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and so on.

[0071] It is apparent that the systems and / or methods described herein can be implemented using different forms of hardware, firmware, and / or a combination of hardware and software. The actual specific control hardware or software code used to implement these systems and / or methods does not limit these aspects. Accordingly, having described the operation and performance of these systems and / or methods without reference to specific software code, it should be understood that software and hardware can be designed to implement these systems and / or methods based at least in part on this description.

[0072] Although combinations of features are set forth in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of each aspect. In fact, many of these features may be combined in ways not specifically set forth in the claims and / or not disclosed in the specification. While each dependent claim listed below directly depends on only one claim, the disclosure of each aspect includes each dependent claim in combination with every other claim in the group of claims. A phrase referring to "at least one" of a list of items refers to any combination of those items (including a single member). For example, "at least one of a, b, or c" is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination having multiple of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c, or any other ordering of a, b, and c).

[0073] No element, act, or instruction used in this application should be construed as critical or essential unless so explicitly described. Additionally, as used herein, the articles "a" and "an" are intended to include one or more and may be used interchangeably with "one or more." Additionally, as used herein, the terms "set" and "group" are intended to include one or more (e.g., related items, unrelated items, combinations of related and unrelated items, etc.) and may be used interchangeably with "one or more." If only one item is intended to be referred to, the phrase "only one" or similar language will be used. Additionally, as used herein, the terms "comprising," "having," "including," etc. are intended to be open-ended terms. Additionally, the phrase "based on" is intended to mean "at least partially based on" unless otherwise explicitly stated.

Claims

1. A method for wireless communication performed by a user equipment (UE), comprising: determining to initiate a random access procedure for a primary cell; and receiving at least one physical downlink control channel (PDCCH) communication on a secondary cell of the primary cell, the at least one PDCCH communication transmitting information associated with the random access procedure for the primary cell, wherein the at least one PDCCH communication includes a retransmission of a scheduled physical uplink shared channel communication of a random access response grant, or a scheduled message type 4 (msg4) physical downlink shared channel communication.

2. The method according to claim 1, wherein, receiving the at least one PDCCH communication includes: monitoring a common search space on the secondary cell to receive the at least one PDCCH communication.

3. The method according to claim 2, wherein, the common search space is a type 1 common search space (CSS) on which downlink control information with cyclic redundancy check is received, and the cyclic redundancy check is scrambled at least in part based on a random access radio network temporary identifier or a temporary cell radio network temporary identifier.

4. The method according to claim 1, wherein, receiving the at least one PDCCH communication includes: monitoring a UE-specific search space configured for cross-carrier scheduling to receive the at least one PDCCH communication.

5. The method according to claim 1, wherein, the at least one PDCCH communication includes at least one downlink control information message.

6. The method according to claim 1, wherein, the at least one PDCCH communication further includes a scheduled random access response physical downlink shared channel.

7. The method according to claim 1, further comprising: transmitting a physical random access channel communication or a physical uplink control channel communication on the primary cell to transmit a feedback message for the scheduled msg4 physical downlink shared channel communication.

8. The method according to claim 7, wherein, the quasi-co-location (QCL) parameters of a control resource set (CORESET) for downlink control information for a scheduled random access response physical downlink shared channel on a type 1 common search space (CSS) are at least in part based on resources associated with the physical random access channel communication, and wherein the resources are at least one of the following: a synchronization signal resource, a physical broadcast channel block resource, or a channel state information reference signal resource.

9. The method according to claim 7, wherein, the quasi-co-location (QCL) parameters of downlink control information for a scheduled random access response physical downlink shared channel on a type 1 common search space (CSS) are at least in part based on a transmission configuration indicator state of a control resource set associated with the at least one PDCCH communication.

10. The method according to claim 7, wherein, The transform precoder for a physical uplink shared channel on the secondary cell scheduled by a random access response grant is at least partially based on the transform precoder in a random access channel message on the primary cell.

11. The method according to claim 7, wherein, The transform precoder for a physical uplink shared channel on the secondary cell scheduled by a random access response grant is at least partially based on the transform precoder configured on the secondary cell.

12. The method according to claim 1, further comprising: Transmitting the physical uplink shared channel communication of the random access response grant on the primary cell.

13. The method according to claim 12, wherein, The physical uplink shared channel communication of the random access response grant is transmitted on the primary cell at least partially based on a random access response uplink grant or a downlink control information message received on the secondary cell.

14. The method according to claim 13, wherein, The frequency domain resource allocation of the downlink control information message is at least partially based on the bandwidth part size of the secondary cell or the primary cell.

15. The method according to claim 1, further comprising: Receiving a specific PDCCH communication on the primary cell to trigger a retransmission of the scheduling of the physical uplink shared channel communication of the random access response grant.

16. The method according to claim 15, further comprising: Monitoring a type 1 common search space (CSS) on the secondary cell and the primary cell to receive the at least one PDCCH communication and the specific PDCCH communication.

17. The method according to claim 16, further comprising: Receiving at least one of the following in the type 1 CSS on the secondary cell: a retransmission of the scheduling of the physical uplink shared channel communication of the random access response grant or a scheduled msg4 physical downlink shared channel communication.

18. The method according to claim 16, further comprising: Receiving, in the type 1 CSS on the primary cell, a message for scheduling the retransmission of the physical uplink shared channel communication of the random access response grant.

19. A user equipment (UE) for wireless communication, comprising: a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors being configured to execute the method according to any one of claims 1 - 18.

20. A non - transitory computer - readable medium storing one or more instructions for wireless communication, the one or more instructions comprising: one or more instructions which, when executed by one or more processors of a user equipment (UE), cause the one or more processors to execute the method according to any one of claims 1 - 18.

21. A device for wireless communication, comprising: a unit for determining to initiate a random access procedure for a primary cell; and A unit for receiving at least one physical downlink control channel (PDCCH) communication on a secondary cell of the primary cell, wherein the at least one PDCCH communication conveys information associated with the random access procedure for the primary cell, and wherein the at least one PDCCH communication includes a retransmission of a scheduling of a physical uplink shared channel communication permitted by a random access response, or a scheduled message type 4 (msg4) physical downlink shared channel communication.

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