Method and apparatus for random access response for two-step random access procedure

Abstract

The invention relates to a method and apparatus for random access response for a two-step random access procedure. Aspects of the present disclosure generally relate to wireless communications. A user equipment (UE) may transmit a random access message including a preamble and a payload. The base station may detect a preamble of the random access message. The base station may fail to decode the payload of the random access message or successfully decode the payload of the random access message. The base station may transmit a random access response based at least in part on detecting the preamble and different decoding results for the payload. The random access response may include an uplink group grant for multiple UEs whose preamble transmissions share the same time and frequency opportunities and an indication of a type of the uplink group grant. The UE may monitor the type and content of the uplink group grant and then transmit data on a shared set of time-frequency resources. Numerous other aspects are provided.

Description

[0001] This patent application is a divisional application of the Chinese patent application No. 202080041330.9 and the international application No. PCT / US2020 / 036354, titled "Method and Apparatus for Random Access Response for a Two-Step Random Access Procedure", filed on June 5, 2020.

[0002] Cross - Reference to Related Applications

[0003] This patent application claims the priority of the US Provisional Patent Application No. 62 / 859,604, titled "DESIGN CONSIDERATIONS FOR RANDOM ACCESS RESPONSE FOR A TWO-STEP RANDOM ACCESS PROCEDURE", filed on June 10, 2019, and the US Non-Provisional Patent Application No. 16 / 892,670, titled "DESIGN CONSIDERATIONS FOR A RANDOM ACCESS RESPONSE FOR A TWO-STEP RANDOM ACCESS PROCEDURE", filed on June 4, 2020. These two applications are hereby incorporated by reference in their entirety. TECHNICAL FIELD

[0004] Aspects of the present disclosure generally relate to wireless communication and relate to techniques and apparatuses for random access response for a two-step random access procedure. BACKGROUND ART

[0005] Wireless communication systems are 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 capable of supporting 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 / LTE-Advanced is an enhanced set of the universal mobile telecommunications system (UMTS) mobile standards promulgated by the 3rd Generation Partnership Project (3GPP).

[0006] A wireless communication network may include several base stations (BSs) capable of supporting communication of several 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 will be described in more detail herein, a BS may be referred to as a B node, a gNB, an access point (AP), a radio head, a transmission reception point (TRP), a new radio (NR) BS, a 5G B node, and so on.

[0007] The above multi-access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipments to communicate at the urban, national, regional, and even global levels. New Radio (NR) (which may also be referred to as 5G) is an enhanced set of the LTE mobile standard promulgated by the Third Generation Partnership Project (3GPP). NR is designed to better support mobile broadband Internet access by improving spectral efficiency, reducing costs, improving services, utilizing new spectrums, and using orthogonal frequency division multiplexing (OFDM) with cyclic prefix (CP) (CP-OFDM) on the downlink (DL), CP-OFDM and / or SC-FDM on the uplink (UL) (e.g., also referred to as discrete Fourier transform spread OFDM (DFT-s-OFDM)), and supporting beamforming, multiple input multiple output (MIMO) antenna technology, and carrier aggregation to better integrate with other open standards. However, as the demand for mobile broadband access continues to grow, there is a need for further improvement in LTE and NR technologies. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. Summary of the Invention

[0008] In some aspects, a wireless communication method performed by a user equipment (UE) may include: transmitting a preamble and a payload of a random access message associated with a two-step random access procedure; receiving a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for a plurality of UEs including the UE and an indication of the type of the uplink group grant; and transmitting uplink communication on a shared time-frequency resource set at least partially based on the uplink group grant.

[0009] 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: transmit a preamble and a payload of a random access message associated with a two-step random access procedure; receive a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for a plurality of UEs including the UE and an indication of a type of the uplink group grant; and transmit uplink communication on a shared time-frequency resource set at least partially based on the uplink group grant.

[0010] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to: transmit a preamble and a payload of a random access message associated with a two-step random access procedure; receive a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for a plurality of UEs including the UE and an indication of a type of the uplink group grant; and transmit uplink communication on a shared time-frequency resource set at least partially based on the uplink group grant.

[0011] In some aspects, a device for wireless communication may include: means for transmitting a preamble and a payload of a random access message associated with a two-step random access procedure; means for receiving a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for a plurality of devices including the device and an indication of a type of the uplink group grant; and means for transmitting uplink communication on a shared time-frequency resource set at least partially based on the uplink group grant.

[0012] In some aspects, a wireless communication method performed by a base station may include: detecting a preamble of a random access message associated with a two-step random access procedure, where the random access message is received from a user equipment (UE); processing the payload of the random access message, where a result of processing the payload is successfully decoding the payload or failing to decode the payload; and transmitting a random access response associated with the two-step random access procedure at least partially based on detecting the preamble and the result of processing the payload, where the random access response includes an uplink group grant for a plurality of UEs including the UE and an indication of a type of the uplink group grant, where preamble transmissions of the plurality of UEs share a time and a frequency opportunity.

[0013] In some aspects, a base station 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: detect a preamble of a random access message associated with a two-step random access procedure, wherein the random access message is received from a user equipment (UE); process a payload of the random access message, wherein a result of processing the payload is successfully decoding the payload or failing to decode the payload; and transmit a random access response associated with the two-step random access procedure at least in part based on detecting the preamble and the result of processing the payload, wherein the random access response includes an uplink group grant for a plurality of UEs including the UE and an indication of a type of the uplink group grant, wherein preamble transmissions of the plurality of UEs share time and frequency opportunities.

[0014] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a base station, may cause the one or more processors to: detect a preamble of a random access message associated with a two-step random access procedure, wherein the random access message is received from a user equipment (UE); process a payload of the random access message, wherein a result of processing the payload is successfully decoding the payload or failing to decode the payload; and transmit a random access response associated with the two-step random access procedure at least in part based on detecting the preamble and the result of processing the payload, wherein the random access response includes an uplink group grant for a plurality of UEs including the UE and an indication of a type of the uplink group grant, wherein preamble transmissions of the plurality of UEs share time and frequency opportunities.

[0015] In some aspects, an apparatus for wireless communication may include: means for detecting a preamble of a random access message associated with a two-step random access procedure, wherein the random access message is received from a user equipment (UE); means for processing a payload of the random access message, wherein a result of processing the payload is successfully decoding the payload or failing to decode the payload; and means for transmitting a random access response associated with the two-step random access procedure at least in part based on detecting the preamble and the result of processing the payload, wherein the random access response includes an uplink group grant for a plurality of UEs including the UE and an indication of a type of the uplink group grant, wherein preamble transmissions of the plurality of UEs share time and frequency opportunities.

[0016] In some aspects, a wireless communication method performed by a base station may include: constructing an uplink group grant for a plurality of UEs performing a two-step random access procedure, wherein a preamble or payload of a random access message provided by the plurality of UEs has been detected by the base station; and transmitting a random access response associated with the two-step random access procedure, wherein the random access response includes the uplink group grant and an indication of the type of the uplink group grant.

[0017] In some aspects, a wireless communication method performed by a UE may include: transmitting a preamble and a payload of a random access message associated with a two-step random access procedure; and receiving, after transmitting the preamble and the payload of the random access message, a random access response associated with the two-step random access procedure, wherein the random access response includes an uplink group grant for a plurality of UEs including the UE, and wherein the random access response includes an indication of the type of the uplink group grant.

[0018] In some aspects, a base station 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: construct an uplink group grant for a plurality of UEs performing a two-step random access procedure, wherein a preamble or payload of a random access message provided by the plurality of UEs has been detected by the base station; and transmit a random access response associated with the two-step random access procedure, wherein the random access response includes the uplink group grant and an indication of the type of the uplink group grant.

[0019] 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: transmit a preamble and a payload of a random access message associated with a two-step random access procedure; and receive, after transmitting the preamble and the payload of the random access message, a random access response associated with the two-step random access procedure, wherein the random access response includes an uplink group grant for a plurality of UEs including the UE, and wherein the random access response includes an indication of the type of the uplink group grant.

[0020] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a base station, may cause the one or more processors to: construct an uplink group grant for a plurality of UEs performing a two-step random access procedure, wherein a preamble or payload of a random access message provided by the plurality of UEs has been detected by the base station; and transmit a random access response associated with the two-step random access procedure, wherein the random access response includes the uplink group grant and an indication of a type of the uplink group grant. In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to: transmit a preamble and a payload of a random access message associated with a two-step random access procedure; and receive, after transmitting the preamble and the payload of the random access message, a random access response associated with the two-step random access procedure, wherein the random access response includes an uplink group grant for a plurality of UEs including the UE, and wherein the random access response includes an indication of a type of the uplink group grant.

[0021] In some aspects, an apparatus for wireless communication may include: means for constructing an uplink group grant for a plurality of UEs performing a two-step random access procedure, wherein a preamble or payload of a random access message provided by the plurality of UEs has been detected by the base station; and means for transmitting a random access response associated with the two-step random access procedure, wherein the random access response includes the uplink group grant and an indication of a type of the uplink group grant.

[0022] In some aspects, an apparatus for wireless communication may include: means for transmitting a preamble and a payload of a random access message associated with a two-step random access procedure; and means for receiving, after transmitting the preamble and the payload of the random access message, a random access response associated with the two-step random access procedure, wherein the random access response includes an uplink group grant for a plurality of UEs including the apparatus, and wherein the random access response includes an indication of a type of the uplink group grant.

[0023] Aspects generally include methods, apparatuses, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and processing systems substantially as described herein with reference to the figures and the description as illustrated in the figures and the description.

[0024] The foregoing has outlined rather broadly the features and technical advantages of examples in accordance with the present disclosure in an effort to enable the following detailed description to be better understood. Additional features and advantages will be described hereinafter. The disclosed concepts and specific examples may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes as the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, in terms of both their organization and method of operation, as well as the associated advantages, will be better understood when the following description is considered in conjunction with the accompanying drawings. Each of the drawings is provided for purposes of illustration and description, and is not to be construed as defining a limitation of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To enable a more particular understanding of the features briefly summarized above, aspects will be described in more detail below, some of which are illustrated in the accompanying drawings. It should be noted, however, that the drawings illustrate only certain typical aspects of the present disclosure and are not to be considered limiting of its scope, as the description may admit to other equally effective aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0026] Figure 1 is a block diagram conceptually illustrating an example of a wireless communication network in accordance with various aspects of the present disclosure.

[0027] Figure 2 is a block diagram conceptually illustrating an example of a base station and a UE in communication in a wireless communication network in accordance with various aspects of the present disclosure.

[0028] Figures 3A - 3C is a diagram illustrating an example associated with a random access response for a two-step random access procedure in accordance with various aspects of the present disclosure.

[0029] Figure 4 is a diagram illustrating an example process, such as may be performed by a base station, in accordance with various aspects of the present disclosure.

[0030] Figure 5 is a diagram illustrating an example process, such as may be performed by a UE, in accordance with various aspects of the present disclosure.

[0031] Figure 6 is a diagram illustrating an example process, such as may be performed by a base station, in accordance with various aspects of the present disclosure.

[0032] Figure 7 is a diagram illustrating an example process, such as may be performed by a UE, in accordance with various aspects of the present disclosure. DETAILED DESCRIPTION

[0033] 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 present disclosure to those skilled in the art. Based on the teachings herein, those skilled in the art should appreciate that the scope of the present disclosure is intended to cover any aspect of the present disclosure disclosed herein, whether implemented independently of or in combination with any other aspect of the present disclosure. For example, any number of the aspects set forth herein may be used to implement an apparatus or practice a method. Additionally, the scope of the present disclosure is intended to cover such apparatus or methods practiced using other structures, functionality, or a combination of structures and functionality that supplement or are additional to the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the present disclosure disclosed herein may be implemented by one or more elements of a claim.

[0034] Certain aspects of a telecommunications system will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in detail hereinafter and illustrated in the drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using hardware, software, or a combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0035] It should be noted that although aspects may be described herein using terminology typically associated with 3G and / or 4G wireless technologies, aspects of the present disclosure may be applied in communication systems based on other generations, such as 5G and later generations, including NR technologies.

[0036] Figure 1 FIG. 100 is a diagram illustrating a wireless network 100 in which aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include several BSs 110 (shown as BS110a, BS110b, BS110c, and BS110d) and other network entities. A BS is an entity that communicates with user equipment (UE) and may 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 may provide communication coverage for a particular geographic area. In 3GPP, the term "cell" may refer to the coverage area of a BS and / or the BS subsystem serving that coverage area, depending on the context in which the term is used.

[0037] The BS can provide communication coverage for macro cells, pico cells, femto cells, and / or another type of cell. A macro cell can cover a relatively large geographical area (e.g., with a radius of several kilometers) and can allow unconstrained access by UEs with a service subscription. A pico cell can cover a relatively small geographical area and can allow unconstrained access by UEs with a service subscription. A femto cell can cover a relatively small geographical area (e.g., a residence) and can allow constrained access by UEs associated with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG)). The BS for a macro cell can be referred to as a macro BS. The BS for a pico cell can be referred to as a pico BS. The BS for a femto cell can be referred to as a femto BS or a home BS. In the example shown in Figure 1 , BS110a can be a macro BS for macro cell 102a, BS110b can be a pico BS for pico cell 102b, and BS110c can be a femto BS for femto cell 102c. The BS can support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "B node", "5G NB", and "cell" can be used interchangeably herein.

[0038] In some aspects, the cell may not have to be stationary, and the geographical area of the cell can move according to the location of the mobile BS. In some aspects, the BSs can be interconnected with each other and / or interconnected to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces such as direct physical connections, virtual networks, and / or analogs using any suitable transport network.

[0039] The wireless network 100 can also include relay stations. A relay station is an entity that can receive the 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 for other UEs. In the example shown in Figure 1 , relay station 110d can communicate with macro BS110a and UE 120d to facilitate communication between BS110a and UE 120d. The relay station can also be referred to as a relay BS, a relay base station, a relay, etc.

[0040] The wireless network 100 can be a heterogeneous network including different types of BSs (e.g., macro BS, pico BS, femto BS, relay BS, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 to 40 watts), while pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 watts).

[0041] The network controller 130 can be coupled to a set of BSs and can provide coordination and control of these BSs. The network controller 130 can communicate with each BS via a backhaul. These BSs can also communicate with each other directly or indirectly, e.g., via a wireless or wired backhaul.

[0042] UEs 120 (e.g., 120a, 120b, 120c) can be dispersed throughout the wireless network 100, and each UE can be stationary or mobile. UEs can also be referred to as access terminals, terminals, mobile stations, subscriber units, stations, 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, a camera, a gaming device, a netbook, a smartbook, a superbook, a medical device or equipment, a biometric sensor / 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), a vehicle component or sensor, a smart meter / sensor, an industrial manufacturing equipment, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium.

[0043] Some UEs can be considered machine type communication (MTC) UEs, or evolved or enhanced machine type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node can provide connectivity to a network (e.g., a wide area network such as the Internet or a cellular network) or provide connectivity to the network, e.g., 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 premise equipment (CPE). The UE 120 can be included inside a housing that houses components of the UE 120, such as processor components, memory components, etc.

[0044] Generally, any number of wireless networks can be deployed in a given geographical area. Each wireless network can support a specific RAT and can operate on one or more frequencies. The RAT can also be referred to as radio technology, air interface, etc. The frequency can also be referred to as carrier, 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.

[0045] 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 intermediary). 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) protocol, vehicle-to-infrastructure (V2I) protocol, etc.), mesh network, etc. In this case, the UE 120 can perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by the base station 110.

[0046] As indicated above, Figure 1 is provided as an example. Other examples may be different from the examples described with respect to Figure 1 which are described.

[0047] Figure 2 FIG. 200 shows a block diagram of a design of the base station 110 and the UE 120, and the base station 110 and the UE 120 can be Figure 1 one of the base stations and one of the UEs in. The base station 110 can be equipped with T antennas 234a to 234t, while the UE 120 can be equipped with R antennas 252a to 252r, where generally T≥1 and R≥1.

[0048] At base station 110, transmit processor 220 may receive data for one or more UEs from data source 212, select one or more modulation and coding schemes (MCSs) for a UE at least in part based on channel quality indicators (CQIs) received from each UE, process (e.g., encode and modulate) data for the UE at least in part based on the MCSs selected for each UE, and provide data symbols for all UEs. 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. 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)). Transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, overhead symbols, and / or reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232a through 232t. Each modulator 232 may process the corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The T downlink signals from modulators 232a through 232t may be transmitted via T antennas 234a through 234t, respectively. According to various aspects described in more detail below, position coding may be utilized to generate synchronization signals to convey additional information.

[0049] 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, respectively. Each demodulator 254 may condition (e.g., filter, amplify, down-convert, and digitize) the 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 on the received symbols when applicable, and provide detected symbols. The receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide the decoded data for the UE 120 to the data sink 260, and provide the decoded control information and system information to the controller / processor 280. The channel processor may determine the reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), channel quality indicator (CQI), etc. In some aspects, one or more components of the UE 120 may be included in a housing.

[0050] On the uplink, at the UE 120, the transmit processor 264 may receive and process data from the data source 262 and control information from the controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by the TX MIMO processor 266 when applicable, further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to the base station 110. At the base station 110, the uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 when applicable, and further processed by the receive processor 238 to obtain the decoded data and control information transmitted by the UE 120. The receive processor 238 may provide the decoded data to the data sink 239 and provide 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.

[0051] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2Any other component(s) thereof may perform one or more techniques for a random access response for a two-step random access procedure, as described in more detail elsewhere herein. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component(s) thereof may perform or direct operations of, for example Figure 4 procedure 400, Figure 5 procedure 500, and / or other procedures described herein. The memories 242 and 282 may store data and program codes for the base station 110 and the UE 120, respectively. The scheduler 246 may schedule the UE for data transmission on the downlink and / or uplink.

[0052] In some aspects, the base station 110 may include: means for detecting a preamble of a random access message associated with a two-step random access procedure, where the random access message is received from the UE 120; means for processing a payload of the random access message, where the result of processing the payload is successfully decoding the payload or failing to decode the payload; and means for transmitting a random access response associated with the two-step random access procedure based at least in part on detecting the preamble and the result of processing the payload, where the random access response includes an uplink group grant for a plurality of UEs including the UE 120 and an indication of the type of the uplink group grant, where the preamble transmissions of the plurality of UEs share time and frequency opportunities; and so on. In some aspects, such means may include one or more components of the base station 110 described in conjunction with Figure 2 herein.

[0053] In some aspects, the base station 110 may include: means for constructing an uplink group grant for a plurality of UEs 120 performing a two-step random access procedure, where the preamble or payload of the random access message provided by the plurality of UEs 120 has been detected by the base station; and means for transmitting a random access response associated with the two-step random access procedure, where the random access response includes the uplink group grant and an indication of the type of the uplink group grant; and so on. In some aspects, such means may include one or more components of the base station 110 described in conjunction with Figure 2 herein.

[0054] In some aspects, UE 120 may include: means for transmitting a preamble and payload of a random access message associated with a two-step random access procedure; means for receiving a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for a plurality of UEs including UE 120 and an indication of the type of the uplink group grant; and means for transmitting uplink communication on a shared time-frequency resource set based at least in part on the uplink group grant; and so on. In some aspects, such means may include one or more components of UE120 as described in conjunction with Figure 2 The UE 120 described.

[0055] In some aspects, UE 120 may include: means for transmitting a preamble and payload of a random access message associated with a two-step random access procedure; means for receiving a random access response associated with the two-step random access procedure after transmitting the preamble and payload of the random access message, wherein the random access response includes an uplink group grant for a plurality of UEs including the UE, and wherein the random access response includes an indication of the type of the uplink group grant; and so on. In some aspects, such means may include one or more components of UE 120 as described in conjunction with Figure 2 The UE 120 described.

[0056] As indicated above, Figure 2 Is provided as an example. Other examples may be different from the example described with respect to Figure 2 The example described.

[0057] The two-step random access channel (RACH) procedure includes two steps (instead of four steps as in the traditional four-step RACH procedure). In the two-step RACH procedure, the UE transmits a random access message (referred to as msgA) including a (e.g., randomly selected) preamble and payload (e.g., a physical uplink shared channel (PUSCH) payload). In an ideal scenario, the base station successfully detects the preamble and successfully decodes the payload, and transmits a random access response (referred to as msgB) to the UE. The random access response includes physical downlink control channel (PDCCH) communication and a physical downlink shared channel (PDSCH) payload, where the PDCCH communication identifies the resources in the PDSCH payload that carry information for the UE. The PDSCH payload may include, for example: contention resolution information for the UE, a cell radio network temporary identifier (C-RNTI) for the UE, a timing advance (TA) command for the UE, and so on. In this ideal scenario (i.e., when the base station detects the msgA preamble and decodes the msgA payload), the random access response associated with the two-step RACH procedure is referred to herein as a successful random access response (successful RAR).

[0058] However, in some cases, the base station may not detect the preamble of the random access message and / or may fail to decode the payload of the random access message. Such situations may occur due to, for example, channel impairments, contention-based multiple access, and so on. Thus, to improve the reliability of the two-step RACH procedure, fallback to the transmission of another random access message (e.g., a message similar to msg3 in the traditional four-step RACH procedure) and / or retransmission of the random access message (e.g., retransmission of msgA) may be supported.

[0059] In a case where the base station successfully detects the preamble of the random access message but fails to decode the payload of the random access message, the base station may send a random access response including the following: a random access preamble identifier (RAPID) associated with the detected preamble, an uplink grant for the UE, a TA command for the UE, and a temporary C-RNTI (TC-RNTI) for the UE. The random access response associated with the two-step RACH procedure in a case where the preamble is detected but the payload is not successfully decoded is referred to herein as a fallback random access response (fallback RAR). Generally, when a UE performing the two-step RACH procedure receives a fallback random access response, the UE falls back to the four-step RACH procedure and transmits another random access message (e.g., msg3) based on the received fallback random access response. Here, the content of the other random access message may be similar to or different from the content of the payload of the random access message transmitted by the UE during the two-step RACH attempt. It is noted that the UE does not need to transmit the preamble together with the other random access message because the base station has already detected the preamble. In a case where the base station does not detect the preamble of the random access message, the base station may send fallback indication information in the random access response media access control (MAC) sub-header (e.g., so that the UE can retransmit the random access message at a later time).

[0060] As indicated above, in the conventional two-step RACH procedure, the base station includes an uplink grant for the UE (e.g., a single UE uplink grant) in a given fallback random access response, but does not include any uplink grant in a successful random access response. This uplink grant design for two-step RACH may result in inefficiencies, for example, in terms of spectral efficiency, power consumption, and signaling overhead.

[0061] Some aspects described herein provide improvements to the uplink grant design for a two-step RACH procedure. For example, in some aspects, the uplink grant included in the fallback random access response can be an uplink group grant for multiple UEs (e.g., to allow the multiple UEs to share uplink resources for further uplink transmissions). As another example, in some aspects, an uplink grant can be included in the successful random access response (e.g., to allow the UE to send additional uplink data without requesting uplink resources). Here, the uplink grant can be a single-UE grant or can be an uplink group grant for multiple UEs. As yet another example, the uplink group grant can be used by UEs that obtain different random access message processing results (e.g., a UE for which decoding of the payload of msgA fails and a second UE for which decoding of the payload of msgA succeeds, where the second UE needs to transmit additional uplink data). As described below, the uplink grant design aspects described herein provide higher spectral efficiency and reduced power consumption while reducing signaling overhead.

[0062] Figures 3A - 3C is a diagram illustrating an example associated with a random access response for a two-step random access procedure in accordance with various aspects of the present disclosure. For purposes of the Figures 3A - 3C example shown in, a UE (e.g., UE 120) is configured to use a two-step RACH procedure associated with a connection to a base station (e.g., base station 110).

[0063] Figure 3A is a diagram of example 300, where the uplink grant included in the fallback random access response is an uplink group grant associated with multiple UEs including the UE. As shown by reference numerals 302 and 304 in Figure 3A , the UE can transmit a preamble of a random access message (msgA preamble) associated with the two-step RACH procedure and a payload of the random access message (msgA payload) associated with the two-step RACH procedure.

[0064] As shown by reference numeral 306, the base station detects the preamble of the random access message. However, as shown by reference numeral 308, the base station fails to decode the payload of the random access message.

[0065] As indicated by reference numeral 310, based at least in part on detecting a preamble and failing to decode a payload, the base station may transmit a random access response associated with a two-step random access procedure, the random access response including an uplink group grant for a plurality of UEs including the UE. In other words, the base station may transmit msgB with a fallback random access response, the fallback random access response including an uplink group grant. In some aspects, the fallback random access response may include a set of K (K≥1) RAPIDs, each RAPID associated with a respective one of the K UEs for which a preamble was detected but the payload was not successfully decoded.

[0066] An uplink group grant is an uplink grant for a plurality of UEs, meaning that the plurality of UEs may share the resources associated with additional uplink transmissions in the uplink grant. In some aspects, the uplink group grant may indicate a set of resources and a modulation and coding scheme (MCS) (e.g., a set of resources and an MCS that the UEs will use to transmit msg3) that the plurality of UEs will use to transmit other random access messages.

[0067] In some aspects, a demodulation reference signal (DMRS) resource configuration (e.g., ports and / or sequences) for a plurality of UEs may be explicitly indicated in the uplink group grant. Alternatively, the DMRS resource configuration for a plurality of UEs may be implicitly indicated by a mapping rule associated with a preamble resource index and a DMRS resource index configured by the base station for the plurality of UEs (e.g., a mapping rule between the preamble resource index and the DMRS resource index, where the preamble resource index may include both a random access channel (RACH) occasion (RO) and a sequence, and the DMRS resource index may include both an antenna port and a sequence).

[0068] In some aspects, the base station may transmit a timing advance (TA) command associated with the UE and a temporary cell radio network temporary identifier (TC-RNTI) associated with the UE separately from the uplink group grant (e.g., such that each of the plurality of UEs can receive the respective TA command and TC-RNTI).

[0069] In some aspects, the uplink group grant may be the only uplink group grant included in the random access response. In other words, in some cases, the random access response transmitted by the base station may include a single uplink group grant for a plurality of UEs.

[0070] Alternatively, in some aspects, the random access response may include multiple uplink group grants. For example, the uplink group grant may be a first uplink group grant, and the multiple UEs may be a first multiple of UEs for which a preamble was detected but the payload was not successfully decoded. In this example, the random access response may further include a second uplink group grant associated with a second multiple of UEs (e.g., a separate uplink group grant for an additional multiple of UEs for which a preamble was detected but the payload was not successfully decoded). In some aspects, the base station may partition the group of UEs into a first multiple of UEs and a second multiple of UEs based at least in part on, for example, proximity of timing offsets associated with a group of UEs or UE states associated with the group of UEs (e.g., derived from rules for msgA preamble, RO selection, etc.).

[0071] In some aspects, the random access response may further include a single-UE uplink grant for another UE. For example, the random access response may include uplink group grants for multiple UEs and may further include a single-UE grant for another UE (e.g., a UE not included in the multiple UEs).

[0072] As further shown by reference numeral 312 in Figure 3A the UE may receive a random access response including an uplink group grant for multiple UEs and may transmit uplink communication (e.g., msg3) based at least in part on the uplink group grant. Here, the UE may individually adjust the timing offset (e.g., based on a TA command associated with the UE) and individually scramble the PUSCH bits, but may use the resource set and MCS indicated by the uplink group grant (i.e., the same resource set and the same MCS as used by other UEs among the multiple UEs).

[0073] Here, the use of the uplink group grant improves spectral efficiency since multiple UEs may use the same resource set and MCS in association with transmitting uplink communication during a two-step RACH procedure. Additionally, by using uplink group grants (instead of multiple single-UE grants), power consumption is reduced at the base station and signaling overhead is reduced.

[0074] Figure 3B is a diagram of example 320, where an uplink grant is included in a successful random access response. As in Figure 3BAs shown by reference numerals 322 and 324 in the figure, the UE may transmit a preamble (msgA preamble) of a random access message associated with a two-step RACH procedure and a payload (msgA payload) of a random access message associated with the two-step RACH procedure. As indicated by reference numeral 324, the payload of the random access message may include an indication that the UE needs to transmit additional uplink data (e.g., in addition to the uplink data included in the payload, the UE also has uplink data ready for transmission). In some aspects, the indication may be in the form of a buffer status report (BSR) included in the payload of the random access message, a scheduling request (SR) included in the payload of the random access message, etc.

[0075] As shown by reference numeral 326, the base station detects the preamble of the random access message. As shown by reference numeral 328, the base station decodes the payload of the random access message. As further shown by reference numeral 328, the base station may determine that the UE needs to transmit additional uplink data. In some aspects, the base station may determine that the UE needs to transmit additional uplink data at least partially based on the indication in the payload of the random access message.

[0076] As shown by reference numeral 330, at least partially based on determining that the UE needs to transmit additional uplink data, the base station may transmit a random access response associated with the two-step random access procedure, and the random access response includes an uplink grant for the UE. In other words, the base station may transmit a successful random access response including an uplink grant.

[0077] In some aspects, the uplink grant may be a single-UE uplink grant for the UE (e.g., an uplink grant specific to the UE). In such cases, in some aspects, the random access response may further include an uplink group grant for a plurality of UEs other than the UE (e.g., for a plurality of other UEs whose payload decoding is successful, and each of the plurality of UEs needs to transmit additional uplink data).

[0078] In some aspects, the uplink grant may be an uplink group grant for multiple UEs including the UE (e.g., for multiple UEs whose payload decoding was successful, where each of the multiple UEs needs to transmit additional uplink data). In some aspects, the grouping of the multiple UEs may be at least partially based on reference signal received power (RSRP) measurements, channel state information (CSI) reports, beam management, quality of service (QoS) handling, location-related measurements, etc. In other words, in some aspects, the base station may group the UEs into a given uplink group grant at least partially based on one or more measurements and / or characteristics determined from the payloads of the random access messages transmitted by each of these UEs. The information carried and / or indicated by the uplink group grant is similar to that described above in conjunction with Figure 3A The information described. In some aspects, the uplink group grant may be the only uplink group grant included in the random access response, or may be one of multiple uplink group grants included in the random access response. Additionally, in some aspects, in the case where the uplink grant is an uplink group grant, the random access response may further include a single-UE uplink grant for another UE.

[0079] As further shown by reference numeral 332 in Figure 3B , the UE may receive a random access response including an uplink grant for the UE and may transmit uplink communication (e.g., including additional uplink data) at least partially based on the uplink grant. Here, if the uplink grant is an uplink group grant, the UE may individually adjust the timing offset (e.g., based on the TA command associated with the UE) and scramble the PUSCH bits, but may use the resource set and MCS indicated by the uplink group grant (i.e., the same resource set and the same MCS used by other UEs among the multiple UEs).

[0080] Here, the use of the uplink grant in a successful random access response may improve spectral efficiency since multiple UEs may use the same resource set and MCS associated with transmitting uplink communication. Additionally, by providing the uplink grant in the successful random access response (instead of waiting for the UE to provide an explicit request for uplink resources), power consumption is reduced at both the UE and the base station and signaling overhead is reduced.

[0081] Figure 3C is a diagram of Example 340 where the uplink grant included in the fallback random access response is an uplink group grant associated with multiple UEs, including UEs for which the decoding of the payload of the random access message failed and UEs for which the decoding of the payload of the random access message was successful.

[0082] In some aspects, a base station may identify a plurality of UEs to which an uplink group grant will be transmitted, associated with a two-step random access procedure, where the plurality of UEs includes a first UE for which decoding of the payload of a first random access message fails and a second UE for which decoding of the payload of a second random access message succeeds.

[0083] For example, as shown by reference numerals 342 and 344, a first UE (UE1) may transmit a preamble of a first random access message and a payload of the first random access message. As shown by reference numeral 346, the base station detects the preamble of the first random access message. However, as shown by reference numeral 348, the base station fails to decode the payload of the first random access message. Further, as shown by reference numerals 350 and 352, a second UE (UE2) may transmit a preamble of a second random access message and a payload of the second random access message. As shown by reference numeral 354, the base station detects the preamble of the second random access message, and as shown by reference numeral 356, successfully decodes the payload of the second random access message. In this example, the base station has identified a plurality of UEs to which an uplink group grant will be transmitted, associated with a two-step random access procedure, where the plurality of UEs includes the first UE (e.g., UE1 for which decoding of the payload of the first random access message fails) and the second UE (e.g., UE2 for which decoding of the payload of the second random access message succeeds).

[0084] As shown by reference numeral 358, at least in part based on identifying the plurality of UEs, the base station may transmit a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for the plurality of UEs including the first UE and the second UE. Notably, in this case, the uplink group grant will be shared by a plurality of UEs having different msgA processing results. In other words, the uplink group grant may be shared by the first UE for which payload decoding fails (e.g., to transmit msg3) and the second UE for which payload decoding succeeds (e.g., to transmit additional uplink communication). Here, a single uplink group grant is needed, rather than separate uplink grants as required in fallback random access responses and successful random access responses.

[0085] In some aspects, in a resource set independent of resources corresponding to a fallback random access response and resources corresponding to a successful random access response, the base station may transmit and the plurality of UEs may receive a random access response. Alternatively, in some aspects, in a resource set shared by a fallback random access response and a successful random access response, the base station may transmit and the UE may receive an uplink group grant.

[0086] In some aspects, the information carried and / or indicated by the uplink group grant may be similar to the information described above in connection with Figure 3A the information described. In some aspects, the uplink group grant may be the only uplink group grant included in the random access response, or may be one of multiple uplink group grants included in the random access response. Additionally, in some aspects, the random access response may further include a single-UE uplink grant for another UE.

[0087] Similar to the above-described manner, the first UE and the second UE may receive a random access response including an uplink group grant and may transmit corresponding uplink communications (e.g., including msg3 and additional uplink data) at least partially based on the uplink group grant.

[0088] Here, the use of the uplink group grant improves spectral efficiency since multiple UEs may use the same resource set and MCS in association with transmitting uplink communications during the two-step RACH procedure. Additionally, by using uplink group grants (instead of multiple single-UE grants), power consumption is reduced at the base station and signaling overhead is reduced. Further, by providing an uplink group grant in the random access response to the UE whose payload decoding was successful (instead of waiting for the UE to provide an explicit request for uplink resources), power consumption is reduced at both the UE and the base station and signaling overhead is reduced.

[0089] As indicated in the above example, the base station may construct one or more uplink group grants for two-step RACH UEs whose preambles or payloads have been detected. In some aspects, the status of the uplink group grant included in the random access response (e.g., msgB) may include information identifying the number of group grants, information identifying the type of group grant, an indication of the type of group grant, and so on. In some aspects, the indication of the type of group grant may be at least partially based on a bit map.

[0090] In some aspects, the random access response may include a random access response PDCCH (e.g., msgB PDCCH) and a random access response PDSCH (e.g., msgB PDSCH) (including DMRS).

[0091] In some aspects, the random access response PDCCH may include downlink control information (DCI) with a cyclic redundancy check (CRC) attached. In some aspects, the CRC may be masked using a group RNTI, such as a RA-RNTI. In some aspects, the random access response PDCCH may be configured within a common search space, which will be monitored by a group of two-step RACH UEs sharing the same RACH occasion used for random access message (e.g., msgA) transmission. In some aspects, the DCI may carry resource assignments for the random access response PDSCH. In some aspects, the DCI may carry an early indication of the type of uplink group grant, such as an uplink group grant in a Fallback RAR, an uplink group grant in a Success RAR, a shared uplink group grant, etc.

[0092] In some aspects, the random access response PDSCH may include a MAC packet data unit (PDU). In some aspects, the MAC PDU may carry at least a Fallback RAR and a Success RAR, where the uplink group grant may be included in the Fallback RAR, the Success RAR, or one or more other fields of the MAC PDU. In some aspects, the uplink group grant field may include at least a common time-frequency resource allocation for subsequent uplink transmissions (e.g., PUSCH transmissions). In some aspects, the uplink group grant field further includes MCS, a PUSCH hopping flag, DMRS resource configuration, and / or common information for power control and beam management.

[0093] As indicated above, Figures 3A - 3C is provided as an example. Other examples may be different from the examples described with respect to Figures 3A - 3C above.

[0094] Figure 4 is a diagram illustrating an example process 400, performed, for example, by a base station, in accordance with various aspects of the present disclosure. Example process 400 is an example where a base station (e.g., base station 110, etc.) performs operations associated with a random access response for a two-step RACH procedure.

[0095] As Figure 4 shown, in some aspects, process 400 may include detecting a preamble of a random access message associated with a two-step random access procedure (block 410). For example, the base station (e.g., using a receiving processor 238, a controller / processor 240, a memory 242, etc.) may detect the preamble of a random access message associated with a two-step random access procedure, as described above. In some aspects, the random access message is received from a UE (e.g., UE 120).

[0096] As in Figure 4As further shown in, in some aspects, process 400 may include processing the payload of the random access message, where the result of processing the payload is successfully decoding the payload or failing to decode the payload (block 420). For example, the base station (e.g., using the receiving processor 238, the controller / processor 240, the memory 242, etc.) may process the payload of the random access message as described above. In some aspects, the result of processing the payload is successfully decoding the payload or failing to decode the payload.

[0097] As in Figure 4 As further shown in, in some aspects, process 400 may include transmitting a random access response associated with the two-step random access procedure based at least in part on detecting the preamble and the result of processing the payload, where the random access response includes an uplink group grant for a plurality of UEs including the UE and an indication of the type of the uplink group grant (block 430). For example, the base station (e.g., using the transmitting processor 220, the receiving processor 238, the controller / processor 240, the memory 242, etc.) may transmit a random access response associated with the two-step random access procedure based at least in part on detecting the preamble and the result of processing the payload as described above. In some aspects, the random access response includes an uplink group grant for a plurality of UEs including the UE and an indication of the type of the uplink group grant. In some aspects, the preamble transmissions of the plurality of UEs share time and frequency opportunities.

[0098] Process 400 may include additional aspects, such as any individual aspect or any combination of aspects described below and / or in combination with one or more other processes described elsewhere herein.

[0099] In a first aspect, when the result of processing the payload of the random access message is failing to decode the payload, the uplink group grant is included in the random access response based at least in part on failing to decode the payload.

[0100] In a second aspect, either alone or in combination with the first aspect, the uplink group grant is included in a fallback random access response.

[0101] In a third aspect, either alone or in combination with one or more of the first and second aspects, the UE is included in the plurality of UEs based at least in part on a timing offset associated with the UE or the UE state of the UE. For example, a group of UEs may be divided into two or more groups of a plurality of UEs including the plurality of UEs based at least in part on the proximity of the timing offset associated with the group of UEs or the UE state associated with the group of UEs.

[0102] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, the uplink group grant indicates a common time-frequency resource set, a modulation and coding scheme (MCS), common information for power control or beam management, and a physical uplink shared channel (PUSCH) hopping flag to be used by the plurality of UEs for transmitting other random access messages.

[0103] In a fifth aspect, either alone or in combination with one or more of the first to fourth aspects, the demodulation reference signal (DMRS) resource configuration for the plurality of UEs is explicitly indicated in the uplink group grant.

[0104] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the demodulation reference signal (DMRS) resource configuration for the plurality of UEs is implicitly indicated by a mapping rule associated with a preamble resource index and a DMRS resource index configured by the base station for the plurality of UEs.

[0105] In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, a timing advance (TA) command associated with the UE and a temporary cell radio network temporary identifier (TC-RNTI) associated with the UE are transmitted separately from the uplink group grant.

[0106] In an eighth aspect, either alone or in combination with one or more of the first to seventh aspects, the uplink group grant is the only uplink group grant included in the random access response.

[0107] In a ninth aspect, either alone or in combination with one or more of the first to eighth aspects, the uplink group grant is one of the multiple uplink group grants included in the random access response.

[0108] In a tenth aspect, either alone or in combination with one or more of the first to ninth aspects, the random access response further includes a single-UE uplink grant for another UE.

[0109] In an eleventh aspect, either alone or in combination with one or more of the first to tenth aspects, the result of processing the payload of the random access message is successful decoding of the payload. Here, the base station can determine that the UE needs to transmit additional uplink data at least partially based on the indication in the payload.

[0110] In a twelfth aspect, either alone or in combination with one or more of the first to eleventh aspects, the uplink group grant is included in a successful random access response.

[0111] In a thirteenth aspect, either alone or in combination with one or more of the first to twelfth aspects, the indication is provided via a buffer status report (BSR).

[0112] In a fourteenth aspect, either alone or in combination with one or more of the first to thirteenth aspects, the indication is provided via a scheduling request (SR).

[0113] In a fifteenth aspect, either alone or in combination with one or more of the first to fourteenth aspects, the UE is grouped into the plurality of UEs based at least in part on at least one of the following: reference signal received power (RSRP) measurement, channel state information (CSI) report, beam management, quality of service (QoS) handling, or positioning-related measurement.

[0114] In a sixteenth aspect, either alone or in combination with one or more of the first to fifteenth aspects, the uplink group grant is transmitted in a resource independent of the resource corresponding to the fallback random access response and the resource corresponding to the successful random access response.

[0115] In a seventeenth aspect, either alone or in combination with one or more of the first to sixteenth aspects, the uplink group grant is transmitted in a resource set shared by the fallback random access response and the successful random access response.

[0116] In an eighteenth aspect, either alone or in combination with one or more of the first to seventeenth aspects, an indication of the type of the uplink group grant is transmitted in a downlink control information (DCI) field of a random access response physical downlink control channel (PDCCH).

[0117] In a nineteenth aspect, either alone or in combination with one or more of the first to eighteenth aspects, the indication of the type of the uplink group grant is based at least in part on a bit mapping.

[0118] In a twentieth aspect, either alone or in combination with one or more of the first to nineteenth aspects, the DCI is associated with a cyclic redundancy check (CRC). Here, the CRC may be masked by a group radio network temporary identifier (RNTI).

[0119] In a twenty-first aspect, either alone or in combination with one or more of the first to twentieth aspects, the random access response PDCCH is transmitted in a common search space.

[0120] Although Figure 4 an example block of process 400 is shown, in some aspects, process 400 may include and Figure 4The boxes depicted in [reference] have fewer boxes, different boxes, or boxes arranged differently compared to the additional boxes. Additionally or alternatively, two or more boxes of process 400 may be executed in parallel.

[0121] Figure 5 is a diagram illustrating an example process 500, such as performed by a UE, in accordance with various aspects of the present disclosure. Example process 500 is an example where a UE (e.g., UE 120, etc.) performs operations associated with a random access response for a two-step RACH procedure.

[0122] As Figure 5 shown in [reference], in some aspects, process 500 may include transmitting a preamble and payload of a random access message associated with a two-step random access procedure (block 510). For example, the UE (e.g., using transmit processor 264, controller / processor 280, memory 282, etc.) may transmit the preamble and payload of a random access message associated with a two-step random access procedure, as described above.

[0123] As further shown in Figure 5 [reference], in some aspects, process 500 may include receiving a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for a plurality of UEs including the UE and an indication of the type of the uplink group grant (block 520). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may receive a random access response associated with the two-step random access procedure, the random access response including an uplink group grant for a plurality of UEs including the UE and an indication of the type of the uplink group grant, as described above.

[0124] As in Figure 5 [reference], in some aspects, process 500 may include transmitting uplink communication on a shared time-frequency resource set based at least in part on the uplink group grant (block 530). For example, the UE (e.g., using transmit processor 264, controller / processor 280, memory 282, etc.) may transmit uplink communication on a shared time-frequency resource set based at least in part on the uplink group grant, as described above.

[0125] Process 500 may include additional aspects, such as any single aspect or any combination of aspects described below and / or in connection with one or more other processes described elsewhere herein.

[0126] In a first aspect, the uplink group grant is included in the random access response at least in part based on the base station's failure to decode the payload.

[0127] In a second aspect, alone or in combination with the first aspect, the uplink group grant is included in the fallback random access response.

[0128] In a third aspect, alone or in combination with one or more of the first and second aspects, the UE is included in the plurality of UEs at least partially based on a timing offset associated with the UE or the UE state of the UE.

[0129] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the uplink group grant indicates a common time-frequency resource set, a modulation and coding scheme (MCS), common information for power control or beam management, and a physical uplink shared channel (PUSCH) hopping flag to be used by the plurality of UEs for transmitting other random access messages.

[0130] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the demodulation reference signal (DMRS) resource configuration for the plurality of UEs is explicitly indicated in the uplink group grant.

[0131] In a sixth aspect, alone or in combination with one or more of the first to fifth aspects, the demodulation reference signal (DMRS) resource configuration for the plurality of UEs is implicitly indicated by a mapping rule associated with a preamble resource index and a DMRS resource index configured by the base station for the plurality of UEs.

[0132] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, a timing advance (TA) command associated with the UE and a temporary cell radio network temporary identifier (TC-RNTI) associated with the UE are received separately from the uplink group grant.

[0133] In an eighth aspect, alone or in combination with one or more of the first to seventh aspects, the uplink group grant is the only uplink group grant included in the random access response.

[0134] In a ninth aspect, alone or in combination with one or more of the first to eighth aspects, the uplink group grant is one of a plurality of uplink group grants included in the random access response.

[0135] In a tenth aspect, alone or in combination with one or more of the first to ninth aspects, the random access response further includes a single-UE uplink grant for another UE.

[0136] In an eleventh aspect, alone or in combination with one or more of the first to tenth aspects, an indication that the UE needs to transmit additional uplink data is included in the payload.

[0137] In a twelfth aspect, either alone or in combination with one or more of the first to eleventh aspects, the uplink group grant is included in a successful random access response.

[0138] In a thirteenth aspect, either alone or in combination with one or more of the first to twelfth aspects, the indication is provided via a buffer status report (BSR).

[0139] In a fourteenth aspect, either alone or in combination with one or more of the first to thirteenth aspects, the indication is provided via a scheduling request (SR).

[0140] In a fifteenth aspect, either alone or in combination with one or more of the first to fourteenth aspects, the UE is grouped into the plurality of UEs based at least in part on at least one of the following: reference signal received power (RSRP) measurement, channel state information (CSI) report, beam management, quality of service (QoS) handling, or positioning-related measurement.

[0141] In a sixteenth aspect, either alone or in combination with one or more of the first to fifteenth aspects, the uplink group grant is received in a resource independent of the resource corresponding to the fallback random access response and the resource corresponding to the successful random access response.

[0142] In a seventeenth aspect, either alone or in combination with one or more of the first to sixteenth aspects, the uplink group grant is received in a resource set shared by the fallback random access response and the successful random access response.

[0143] In an eighteenth aspect, either alone or in combination with one or more of the first to seventeenth aspects, the indication of the type of the uplink group grant is received in a downlink control information (DCI) field of the random access response physical downlink control channel (PDCCH) based at least in part on monitoring the random access response PDCCH.

[0144] In a nineteenth aspect, either alone or in combination with one or more of the first to eighteenth aspects, the DCI is associated with a cyclic redundancy check (CRC). Here, the CRC can be demasked using a group radio network temporary identifier (RNTI).

[0145] In a twentieth aspect, either alone or in combination with one or more of the first to nineteenth aspects, the DCI is decoded to determine a resource assignment for the random access response physical downlink shared channel (PDSCH). Here, the indication of the type of the uplink group grant can be carried in the random access response PDSCH.

[0146] In a twenty - first aspect, alone or in combination with one or more of the first to twentieth aspects, the random access response and the uplink group grant are decoded.

[0147] In a twenty - second aspect, alone or in combination with one or more of the first to twenty - first aspects, timing advance (TA), modulation and coding scheme (MCS), power control, beam management, and time - frequency resource allocation are applied in association with transmitting the uplink communication.

[0148] Although Figure 5 example blocks of process 500 are shown, in some aspects, process 500 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks compared to the blocks depicted in Figure 5 . Additionally or alternatively, two or more blocks of process 500 may be executed in parallel.

[0149] Figure 6 is a diagram illustrating an example process 600, such as performed by a base station, in accordance with various aspects of the present disclosure. Example process 600 is an example in which a base station (e.g., base station 110, etc.) performs operations associated with design considerations for a random access response for a two - step random access procedure.

[0150] As Figure 6 shown, in some aspects, process 600 may include constructing an uplink group grant for a plurality of UEs performing a two - step random access procedure, where the preambles or payloads of the random access messages provided by the plurality of UEs have been detected by the base station (block 610). For example, the base station (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242, etc.) may construct an uplink group grant for a plurality of UEs (e.g., UE 120) performing a two - step random access procedure, as described above. In some aspects, the preambles or payloads of the random access messages provided by the plurality of UEs have been detected by the base station.

[0151] As further shown in Figure 6 , in some aspects, process 600 may include transmitting a random access response associated with the two - step random access procedure, where the random access response includes the uplink group grant and an indication of the type of the uplink group grant (block 620). For example, the base station (e.g., using transmit processor 220, controller / processor 240, memory 242, etc.) may transmit a random access response associated with the two - step random access procedure, as described above. In some aspects, the random access response includes the uplink group grant and an indication of the type of the uplink group grant.

[0152] Procedure 600 may include additional aspects, such as any individual aspect or any combination of aspects described below and / or in connection with one or more other procedures described elsewhere herein.

[0153] In a first aspect, the random access response includes the status of the uplink grant group, the status including at least one of the following: information identifying the number of uplink grants included in the random access response, or an indication of the type of the uplink grant.

[0154] In a second aspect, either alone or in combination with the first aspect, the indication of the type of the uplink grant is transmitted in a DCI field of a random access response PDCCH.

[0155] In a third aspect, either alone or in combination with one or more of the first and second aspects, the indication of the type of the uplink grant is at least partially based on a bit mapping.

[0156] In a fourth aspect, either alone or in combination with one or more of the first to third aspects, the DCI is associated with a CRC, and the CRC is masked by a group RNTI.

[0157] In a fifth aspect, either alone or in combination with one or more of the first to fourth aspects, the random access response PDCCH is transmitted in a common search space.

[0158] Although Figure 6 illustrates example blocks of procedure 600, in some aspects, procedure 600 may include additional blocks, fewer blocks, different blocks, or blocks arranged differently compared to the blocks depicted in Figure 6 . Additionally or alternatively, two or more blocks of procedure 600 may be executed in parallel.

[0159] Figure 7 is a diagram illustrating an example procedure 700, such as performed by a UE, in accordance with various aspects of the present disclosure. Example procedure 700 is an example where a UE (e.g., UE 120, etc.) performs operations associated with design considerations for a random access response for a two-step random access procedure.

[0160] As Figure 7 shown, in some aspects, procedure 700 may include transmitting a preamble and a payload of a random access message associated with a two-step random access procedure (block 710). For example, the UE (e.g., using a transmit processor 264, a controller / processor 280, a memory 282, etc.) may transmit a preamble and a payload of a random access message associated with a two-step random access procedure, as described above.

[0161] As in Figure 7As further shown, in some aspects, process 700 may include receiving a random access response associated with a two-step random access procedure after transmitting the preamble and payload of the random access message, where the random access response includes an uplink group grant for a plurality of UEs including the UE, and where the random access response includes an indication of the type of the uplink group grant (block 720). For example, the UE (e.g., using receive processor 258, controller / processor 280, memory 282, etc.) may receive a random access response associated with a two-step random access procedure after transmitting the preamble and payload of the random access message, as described above. In some aspects, the random access response includes an uplink group grant for a plurality of UEs including the UE, and where the random access response includes an indication of the type of the uplink group grant.

[0162] Process 700 may include additional aspects, such as any individual aspect or any combination of aspects described below and / or in connection with one or more other processes described elsewhere herein.

[0163] In a first aspect, the random access response includes the status of the uplink group grant, the status including at least one of the following: information identifying the number of uplink group grants included in the random access response, or an indication of the type of the uplink group grant.

[0164] In a second aspect, either alone or in combination with the first aspect, the indication of the type of the uplink group grant is received in a DCI field of a random access response PDCCH.

[0165] In a third aspect, either alone or in combination with one or more of the first and second aspects, the indication of the type of the uplink group grant is at least partially based on a bit map.

[0166] In a fourth aspect, either alone or in combination with one or more of the first through third aspects, the DCI is associated with a CRC, where the CRC is masked by a group RNTI.

[0167] In a fifth aspect, either alone or in combination with one or more of the first through fourth aspects, the random access response PDCCH is received in a common search space.

[0168] Although Figure 7 example blocks of process 700 are shown, in some aspects, process 700 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks compared to the blocks depicted in Figure 7 In addition, or alternatively, two or more blocks of process 700 may be executed in parallel.

[0169] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations can be made in light of the above disclosure or can be obtained by practicing the aspects.

[0170] As used herein, the term "component" is intended to be broadly construed as hardware, firmware, and / or a combination of hardware and software. As used herein, a processor is implemented with hardware, firmware, and / or a combination of hardware and software.

[0171] As used herein, depending on the context, meeting a threshold can mean that a value is 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.

[0172] It will be apparent that the systems and / or methods described herein can be implemented in different forms of hardware, firmware, and / or a combination of hardware and software. The actual special control hardware or software code used to implement these systems and / or methods does not limit the aspects. Thus, the operation and behavior of these systems and / or methods are described herein without reference to specific software code—understanding that software and hardware can be designed to implement these systems and / or methods at least in part based on the description herein.

[0173] Although specific feature combinations are recited in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of the various aspects. In fact, many of these features can be combined in ways not specifically recited in the claims and / or not disclosed in the specification. Although each of the dependent claims listed below can directly depend on only one claim, the disclosure of the various aspects includes each dependent claim in combination with each other claim in this group of claims. The phrase reciting "at least one of" a list of items refers to any combination of those items, including a single member. As an 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 identical elements (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).

[0174] The elements, acts, or instructions used herein should not be construed as critical or essential unless expressly described as such. Also, as used herein, the articles "a" and "an" are intended to include one or more items 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 items (e.g., related items, unrelated items, combinations of related and unrelated items, etc.) and may be used interchangeably with "one or more." Where only one item is intended, the phrase "only one" or similar language is used. Also, as used herein, the terms "having," "containing," "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 expressly stated.

Claims

1. A method for wireless communication at a user equipment (UE), comprising: Transmitting a preamble and a payload of a random access message associated with a two-step random access procedure; Receiving a random access response associated with the two-step random access procedure, the random access response including an uplink grant for a plurality of UEs including the UE, a status of the uplink grant, and an indication of a type of the uplink grant; Wherein the status includes information identifying a number of uplink grants included in the random access response; Wherein the indication of the type of the uplink grant is capable of indicating that the uplink grant is for one of a fallback random access response, a successful random access response, or a shared uplink grant; and Wherein the uplink grant is transmitted in a resource set shared by the fallback random access response and the successful random access response; And Transmitting an uplink communication on a shared time-frequency resource set at least partially based on the uplink grant.

2. The method according to claim 1, wherein the uplink grant included in the random access response indicates that a network entity fails to decode the payload.

3. The method according to claim 2, wherein the uplink grant is included in the fallback random access response.

4. The method according to claim 2, wherein the UE is included in the plurality of UEs at least partially based on a timing offset associated with the UE or a UE state of the UE.

5. The method according to claim 1, wherein the uplink grant indicates a shared time-frequency resource set, a modulation and coding scheme (MCS), shared information for power control or beam management, and a physical uplink shared channel (PUSCH) hopping flag that will be used by the plurality of UEs to transmit other random access messages.

6. The method according to claim 1, wherein a demodulation reference signal (DMRS) resource configuration for the plurality of UEs is explicitly indicated in the uplink grant.

7. The method according to claim 1, wherein a demodulation reference signal (DMRS) resource configuration for the plurality of UEs is implicitly indicated by a mapping rule associated with a preamble resource index and a DMRS resource index configured by a network entity for the plurality of UEs.

8. The method according to claim 1, wherein a timing advance (TA) command associated with the UE and a temporary cell radio network temporary identifier (TC-RNTI) associated with the UE are received separately from the uplink grant.

9. The method according to claim 1, wherein the uplink grant is a single uplink grant included in the random access response.

10. The method according to claim 1, wherein the uplink grant is one of a plurality of uplink grants included in the random access response.

11. The method according to claim 1, wherein the random access response further includes a single-UE uplink grant for another UE.

12. The method according to claim 1, wherein an indication that the UE needs to transmit additional uplink data is included in the payload of the random access message.

13. The method according to claim 11, wherein the uplink grant is included in the successful random access response.

14. The method according to claim 11, wherein the indication of the type of the uplink grant is provided via a buffer status report BSR.

15. The method according to claim 11, wherein the indication of the type of the uplink grant is provided via a scheduling request SR.

16. The method according to claim 11, wherein the UE is grouped into the plurality of UEs based at least in part on at least one of the following: Reference signal received power RSRP measurement, Channel state information CSI report, Beam management, Quality of service QoS handling, or Location-related measurement.

17. A user equipment UE for wireless communication, comprising: A memory; And One or more processors coupled to the memory, the one or more processors operable individually or in any combination to cause the UE to: Transmit a preamble and a payload of a random access message associated with a two-step random access procedure; Receive a random access response associated with the two-step random access procedure, the random access response including an uplink grant for a plurality of UEs including the UE, a status of the uplink grant, and an indication of the type of the uplink grant; Wherein the status includes information identifying the number of uplink grants included in the random access response, Wherein the indication of the type of the uplink grant can indicate that the uplink grant is for one of a fallback random access response or a successful random access response, and Wherein the uplink grant is transmitted in a resource set shared by the fallback random access response and the successful random access response; and Transmit uplink communication on a shared time-frequency resource set based at least in part on the uplink grant.

18. The UE according to claim 17, wherein the uplink grant included in the random access response indicates that a network entity fails to decode the payload.

19. The UE according to claim 17, wherein the uplink grant is included in the successful random access response.

20. A network entity for wireless communication, comprising: A memory; And One or more processors coupled to the memory, the one or more processors operable individually or in any combination to cause the network entity to: Detect a preamble of a random access message associated with a two-step random access procedure, Wherein the random access message is received from a user equipment UE; Process the payload of the random access message, wherein the result of processing the payload is successfully decoding the payload or failing to decode the payload; And Transmit a random access response associated with the two-step random access procedure based at least in part on detecting the preamble and the result of processing the payload, wherein the random access response includes an uplink grant for a plurality of UEs including the UE, a status of the uplink grant, and an indication of a type of the uplink grant, wherein the status includes information identifying a number of uplink grants included in the random access response, wherein the indication of the type of the uplink grant is capable of indicating that the uplink grant is for one of a fallback random access response or a successful random access response, wherein preamble transmissions of the plurality of UEs share a time and frequency opportunity, and wherein the uplink grant is transmitted in a resource set shared by the fallback random access response and the successful random access response.

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