Instructions on TBS scaling and repetition for MSG4 PDSCH

Abstract

Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques and mechanisms for indicating transport block size (TBS) scaling and / or repetition for a Msg4 physical downlink shared channel (PDSCH).

Description

[0001] background

[0002] Public domain

[0003] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques and mechanisms for indicating transport block size (TBS) scaling and / or repetition for a Msg4 physical downlink shared channel (PDSCH).

[0004] Related technical description

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcast, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, 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, and Time Division Synchronous Code Division Multiple Access (TD-SCDMA) systems, to name just a few.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide common protocols that enable different wireless devices to communicate at city, country, region, and even global levels. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is an enhancement set of the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by using OFDMA with cyclic prefix (CP) on downlink (DL) and uplink (UL) to improve spectrum efficiency, reduce costs, improve services, utilize new spectrum, and better integrate with other open standards. To this end, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation.

[0007] However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should be applicable to other multiple access technologies and the telecommunication standards that employ these technologies.

[0008] Overview

[0009] The systems, methods, and devices of the present disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the present disclosure as expressed in the appended claims, some features will now be briefly discussed. After considering this discussion, and especially after reading the section entitled "Detailed Description," it will be understood how the features of the present disclosure can provide advantages such as improved reliability of message decoding and reduced decoding complexity.

[0010] Certain aspects provide a method for wireless communications by a user equipment (UE). The method generally includes: indicating to a network entity at least one of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; determining, as part of the random access channel (RACH) procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for implementing a reduced code rate applicable to the limited capabilities of the UE; and processing the PDSCH according to the determined transmission parameters.

[0011] Certain aspects provide a method for wireless communications by a network entity. The method generally includes: receiving from a user equipment (UE) an indication of at least one of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; determining, as part of the RACH procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for implementing a reduced code rate applicable to the limited capabilities of the UE; and transmitting the PDSCH to the UE according to the determined transmission parameters.

[0012] Aspects of the present disclosure provide apparatuses, devices, processors, and computer-readable media for performing the methods described herein.

[0013] Aspects of the present disclosure provide apparatuses, devices, processors, and computer-readable media for performing techniques and methods that may be complementary to operations performed by a UE as described herein (eg, performed by a BS).

[0014] To achieve the foregoing and related ends, one or more aspects include features fully described below and particularly pointed out in the claims. The following description and the accompanying drawings set forth in detail certain illustrative features of one or more aspects. However, these features are only indicative of several of the various ways in which the principles of the various aspects can be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to understand in detail the manner in which the above-stated features of the present disclosure are used, a more particular description of the content briefly summarized above may be made with reference to various aspects, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying 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.

[0017] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure.

[0018] Figure 2 is a block diagram illustrating an example architecture of a distributed radio access network (RAN) in accordance with certain aspects of the present disclosure.

[0019] Figure 3 is a block diagram illustrating an example of a communication protocol stack for implementing an example RAN architecture, in accordance with certain aspects of the present disclosure.

[0020] Figure 4 is a block diagram conceptually illustrating designs of example base stations (BSs) and user equipment (UEs) in accordance with certain aspects of the present disclosure.

[0021] Figure 5 An example system architecture for interworking between a 5G system (5GS) and an Evolved Universal Mobile Telecommunications System Network (E-UTRAN) system in accordance with certain aspects of the present disclosure is illustrated.

[0022] Figure 6 An example of a frame format for a telecommunications system is illustrated in accordance with certain aspects of the present disclosure.

[0023] Figure 7 is a timing diagram illustrating an example four-step RACH procedure in accordance with certain aspects of the present disclosure.

[0024] Figure 8 is a timing diagram illustrating an example two-step RACH procedure in accordance with certain aspects of the present disclosure.

[0025] Fig. 9 Capabilities of various types of UEs in accordance with certain aspects of the present disclosure are illustrated.

[0026] Fig. 10A and 10B An example MCS index table for PDSCH is shown in accordance with certain aspects of the present disclosure.

[0027] Fig.11 is a table comparing two-step RACH and four-step RACH in accordance with certain aspects of the present disclosure.

[0028] Fig.12An example of PDSCH repetition in accordance with certain aspects of the present disclosure is illustrated.

[0029] Fig.13

[0013] Example operations for wireless communications by a UE are illustrated in accordance with certain aspects of the present disclosure.

[0030] Fig.14

[0013] Example operations for wireless communications by a network entity are illustrated in accordance with certain aspects of the present disclosure.

[0031] Fig.15 is a set of tables illustrating diversion of an indication field for a transport block size (TBS) in accordance with certain aspects of the present disclosure.

[0032] Fig.16 is a set of tables illustrating the diversion of modulation and coding scheme (MCS) and downlink assignment index (DAI) fields for transport block size (TBS) in accordance with certain aspects of the present disclosure.

[0033] Fig.17 is a table illustrating how scaling and repetition may be signaled via bits of the TBS scaling field in accordance with certain aspects of the present disclosure.

[0034] Fig.18 Illustrated are communications devices that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

[0035] Fig.19 Illustrated are communications devices that may include various components configured to perform operations for the techniques disclosed herein in accordance with aspects of the present disclosure.

[0036] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation.

[0037] Detailed Description

[0038] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques and mechanisms for indicating transmission parameters, such as transport block size (TBS) scaling and / or repetition, of a physical downlink shared channel (PDSCH) transmission (e.g., Msg4 PDSCH) for a random access channel procedure. The transmission parameters may be selected to enhance reliability for UEs with limited capabilities, such as reduced capability (RedCap) UEs.

[0039] The following description provides examples rather than limiting the scope, applicability, or examples set forth in the claims. Changes may be made to the functions and arrangements of the elements discussed without departing from the scope of the present disclosure. Various examples may appropriately omit, replace, or add various procedures or components. For example, the described method may be performed in an order different from the order described, and various steps may be added, omitted, or combined. Moreover, the features described with reference to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement a device or practice method. In addition, the scope of the present disclosure is intended to cover such devices or methods practiced using other structures, functionality, or structures and functionality as supplements to the various aspects of the present disclosure set forth herein or in addition. It should be understood that any aspect of the present disclosure disclosed herein may be implemented by one or more elements of the claims. The wording "exemplary" is used herein to mean "used as an example, instance, or explanation". Any aspect described as "exemplary" herein is not necessarily to be interpreted as being superior to or superior to other aspects.

[0040] The technology described herein can be used for various wireless communication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network can implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes other variants of Wideband CDMA (WCDMA) and CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network can implement radio technologies such as Global System for Mobile Communications (GSM). An OFDMA network can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are parts of Universal Mobile Telecommunications System (UMTS).

[0041] New Radio (NR) is an emerging wireless communication technology being developed in collaboration with the 5G Technology Forum (5GTF). 3GPP Long Term Evolution (LTE) and Advanced LTE (LTE-A) are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization called "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization called "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, although various aspects may be described herein using terms commonly associated with 3G and / or 4G wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations, such as 5G and later generations, including NR technologies.

[0042] New Radio (NR) access (e.g., 5G technology) can support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., 80 MHz or higher), millimeter wave (mmW) targeting high carrier frequency (e.g., 25 GHz or higher), massive machine type communication MTC (mMTC) targeting non-backward compatible MTC technology, and / or mission critical services targeting ultra-reliable low latency communication (URLLC). These services may include latency and reliability requirements. These services may also have different transmission time intervals (TTIs) to meet corresponding quality of service (QoS) requirements. In addition, these services can coexist in the same subframe.

[0043] Example Wireless Communication System

[0044] Figure 1 An example wireless communication network 100 is illustrated in which aspects of the present disclosure may be performed. For example, a UE 120 may be configured to perform Fig.13 Operation 1300 of determining the transmission parameters for Msg4 PDSCH. Similarly, base station 110 may be configured to perform Fig.14 Operation 1400 of indicating the transmission parameters for Msg4 PDSCH to the UE (e.g., performing Fig.13 Operation 1300).

[0045] like Figure 1As explained in , the wireless communication network 100 may include several base stations (BS) 110 and other network entities. The BS may be a station that communicates with a user equipment (UE). Each BS 110 may provide communication coverage for a specific geographical area. In 3GPP, the term "cell" may refer to the coverage area of ​​a B node (NB) and / or a NB subsystem that serves the coverage area, depending on the context in which the term is used. In the NR system, the term "cell" and the next generation B node (gNB or gNodeB), NRBS, 5GNB, access point (AP), or transmission reception point (TRP) may be interchangeable. In some examples, the cell may not necessarily be stationary, and the geographical area of ​​the cell may move according to the location of the mobile BS. In some examples, the base station may use any suitable transmission network to interconnect with each other and / or to one or more other base stations or network nodes (not shown) in the wireless communication network 100 through various types of backhaul interfaces (such as direct physical connections, wireless connections, virtual networks, etc.).

[0046] In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a specific radio access technology (RAT) and may operate on one or more frequencies. RAT may also be referred to as radio technology, air interface, etc. Frequency may also be referred to as carrier, subcarrier, frequency channel, frequency modulation, subband, etc. Each frequency may support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

[0047] A BS may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a residence, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1In the example shown in FIG. 1 , BSs 110a, 110b, and 110c may be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x may be a pico BS for pico cell 102x. BSs 110y and 110z may be femto BSs for femto cells 102y and 102z, respectively. A BS may support one or more (e.g., three) cells.

[0048] The wireless communication network 100 may also include a relay station. A relay station is a station that receives transmissions of data and / or other information from an upstream station (e.g., a BS or a UE) and sends transmissions of the data and / or other information to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that relays transmissions for other UEs. Figure 1 In the example shown in , a relay station 110r may communicate with a BS 110a and a UE 120r to facilitate communication between the BS 110a and the UE 120r. A relay station may also be referred to as a relay BS, a relay, or the like.

[0049] The wireless communication network 100 may be a heterogeneous network including different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relays, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in the wireless communication network 100. For example, a macro BS may have a high transmit power level (e.g., 20 watts), while a pico BS, a femto BS, and a relay may have a lower transmit power level (e.g., 1 watt).

[0050] The wireless communication network 100 may support synchronous or asynchronous operation. For synchronous operation, each BS may have similar frame timing, and transmissions from different BSs may be roughly aligned in time. For asynchronous operation, each BS may have different frame timing, and transmissions from different BSs may not be aligned in time. The techniques described herein may be used for both synchronous and asynchronous operation.

[0051] A network controller 130 may couple to a set of BSs and provide coordination and control for the BSs. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other (eg, directly or indirectly) via a wireless or wired backhaul.

[0052] UE 120 (e.g., 120x, 120y, etc.) may be dispersed throughout the wireless communication network 100, and each UE may be stationary or mobile. UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smart phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical equipment, biometric sensor / device, wearable device (such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), transportation component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate via wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node can provide connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0053] Some wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also often referred to as frequency modulation, frequency bins, etc. Each subcarrier can be modulated with data. In general, modulation symbols are sent in the frequency domain for OFDM and in the time domain for SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing of subcarriers can be 15kHz, and the minimum resource allocation (called a "resource block" (RB)) can be 12 subcarriers (or 180kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (ie, 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0054] Although aspects of the examples described herein may be associated with LTE technology, aspects of the present disclosure may be applicable to other wireless communication systems, such as NR. NR may utilize OFDM with CP on the uplink and downlink and include support for half-duplex operation using TDD. Beamforming may be supported and the beam direction may be dynamically configured. MIMO transmission with precoding may also be supported. MIMO configurations in the DL may support up to 8 transmit antennas (with multi-layer DL transmissions of up to 8 streams) and up to 2 streams per UE. Multi-layer transmissions of up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported using up to 8 serving cells.

[0055] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., BS) allocates resources for communication between some or all devices and equipment within its service area or cell. A scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, subordinate entities utilize resources allocated by the scheduling entity. A base station is not the only entity that can be used as a scheduling entity. In some examples, a UE may act as a scheduling entity, and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize resources scheduled by the UE for wireless communication. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In a mesh network example, UEs may communicate directly with each other in addition to communicating with a scheduling entity.

[0056] exist Figure 1 In FIG. 1 , a solid line with double arrows indicates desired transmissions between a UE and a serving BS, which is a BS designated to serve the UE on a downlink and / or uplink. A thin dashed line with double arrows indicates interfering transmissions between a UE and a BS.

[0057] Figure 2 An example architecture of a distributed radio access network (RAN) 200 is illustrated. Figure 1 The wireless communication network 100 described in the embodiment is implemented in FIG. Figure 2 As shown in FIG. 1 , the distributed RAN includes a core network (CN) 202 and access nodes 208 .

[0058] The CN 202 may host core network functions. The CN 202 may be centrally deployed. The CN 202 functionality may be offloaded (e.g., to Advanced Wireless Services (AWS)) in an effort to handle peak capacity. The CN 202 may include an access and mobility management function (AMF) 204 and a user plane function (UPF) 206. The AMF 204 and the UPF 206 may perform one or more core network functions.

[0059] AN 208 may communicate with CN 202 (e.g., via a backhaul interface). AN 208 may communicate with AMF 204 via an N2 (e.g., NG-C) interface. AN 208 may communicate with UPF 208 via an N3 (e.g., NG-U) interface. AN 208 may include a central unit control plane (CU-CP) 210, one or more central unit user planes (CU-UP) 212, one or more distributed units (DU) 214-218, and one or more antenna / remote radio units (AU / RRU) 220-224. CU and DU may also be referred to as gNB-CU and gNB-DU, respectively. One or more components of AN 208 may be implemented in gNB 226. AN 208 may communicate with one or more neighboring gNBs.

[0060] The CU-CP 210 may be connected to one or more of the DUs 214-218. The CU-CP 210 and the DUs 214-218 may be connected via an F1-C interface. Figure 2 As shown in FIG. 1 , the CU-CP 210 may be connected to a plurality of DUs, but these DUs may be connected to only one CU-CP. Figure 2 Only one CU-UP 212 is illustrated, but the AN 208 may include multiple CU-UPs. The CU-CP 210 selects the appropriate CU-UP(s) for the requested service (eg, for a UE).

[0061] The CU-UPs 212 may be connected to the CU-CP 210. For example, the DU-UPs 212 and the CU-CP 210 may be connected via an E1 interface. The CU-CP 212 may be connected to one or more DUs 214-218. The CU-UPs 212 and the DUs 214-218 may be connected via an F1-U interface. Figure 2 As shown in , the CU-CP 210 may be connected to a plurality of CU-UPs, but each CU-UP may be connected to only one CU-CP.

[0062] A DU (such as DU 214, 216 and / or 218) may host one or more TRPs (transmission / reception points, which may include edge nodes (ENs), edge units (EUs), radio heads (RHs), smart radio heads (SRHs), etc.). A DU may be located at the edge of a network with radio frequency (RF) functionality. A DU may be connected to multiple CU-UPs, which are connected to the same CU-CP (e.g., under the control of the same CU-CP) (e.g., for RAN sharing, radio as a service (RaaS), and service-specific deployments). A DU may be configured to serve traffic to a UE individually (e.g., dynamically selected) or jointly (e.g., jointly transmitted). Each DU 214-216 may be connected to one of the AU / RRUs 220-224.

[0063] The CU-CP 210 may be connected to multiple DUs that are connected to the same CU-UP 212 (e.g., under the control of the same CU-UP 212). Connectivity between the CU-UP 212 and the DUs may be established by the CU-CP 210. For example, a bearer context management function may be used to establish connectivity between the CU-UP 212 and the DUs. Data forwarding between the CU-UPs 212 may be via an Xn-U interface.

[0064] The distributed RAN 200 may support forward haul solutions across different deployment types. For example, the RAN 200 architecture may be based on transport network capabilities (e.g., bandwidth, latency, and / or jitter). The distributed RAN 200 may share features and / or components with LTE. For example, the AN 208 may support dual connectivity with NR and may share a common forward haul for LTE and NR. The distributed RAN 200 may, for example, enable collaboration between and among the DUs 214-218 via the CU-CP 212. Inter-DU interfaces may not be used.

[0065] The various logical functions may be dynamically distributed in the distributed RAN 200. Figure 3Described in more detail, a radio resource control (RRC) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, a medium access control (MAC) layer, a physical (PHY) layer and / or a radio frequency (RF) layer may be adaptively placed in the AN and / or the UE.

[0066] Figure 3 A diagram showing an example of a communication protocol stack 300 for implementing a RAN (e.g., such as RAN 200) according to various aspects of the present disclosure is illustrated. The illustrated communication protocol stack 300 may be implemented by a device operating in a wireless communication system (e.g., a 5G NR system) (e.g., wireless communication network 100). In various examples, the layers of the protocol stack 300 may be implemented as separate software modules, as part of a processor or ASIC, as part of non-co-located devices connected by a communication link, or various combinations thereof. Co-located and non-co-located implementations may be used, for example, in a protocol stack for a network access device or UE. As shown in FIG. Figure 3 As shown in , the system can support various services on one or more protocols. One or more protocol layers of the protocol stack 300 can be implemented by the AN and / or the UE.

[0067] like Figure 3 As shown in FIG, the protocol stack 300 is implemented in an AN (e.g., Figure 2 The RRC layer 305, the PDCP layer 310, the RLC layer 315, the MAC layer 320, the PHY layer 325, and the RF layer 530 may be implemented by the AN. For example, the CU-CP (e.g., Figure 2 210) and CU-UP (e.g., Figure 2 CU-UP 212 in each of the DUs may implement the RRC layer 305 and the PDCP layer 310. Figure 2 DU 214-218 in the AU / RRU (e.g., Figure 2 The AU / RRU 220-224 in the RF module may implement the PHY layer(s) 325 and the RF layer(s) 330. The PHY layer 325 may include a high PHY layer and a low PHY layer.

[0068] The UE may implement the entire protocol stack 300 (eg, the RRC layer 305, the PDCP layer 310, the RLC layer 315, the MAC layer 320, the PHY layer(s) 325, and the RF layer(s) 330).

[0069] Figure 4 Explained (such as Figure 11 and 120, which may be used to implement aspects of the present disclosure. For example, antenna 452, processors 466, 458, 464, and / or controller / processor 480 of UE 120 may be configured to perform operations related to Fig.13 The operations described herein, while a similar processor of BS 110 may perform operations related to Fig.14 The operation described.

[0070] At BS 110, transmit processor 420 may receive data from data source 412 and control information from controller / processor 440. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), a physical downlink control channel (PDCCH), a group common PDCCH (GC PDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. Processor 420 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Processor 420 may also generate reference symbols (e.g., of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a cell-specific reference signal (CRS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 430 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, and / or reference symbols, where applicable, and may provide an output symbol stream to modulators (MODs) 432a to 432t. Each modulator 432 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from modulators 432a to 432t may be transmitted via antennas 434a to 434t, respectively.

[0071] At UE 120, antennas 452a to 452r may receive downlink signals from base station 110 and may provide received signals to demodulators (DEMODs) 454a to 454r in the transceiver, respectively. Each demodulator 454 may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 456 may obtain received symbols from all demodulators 454a to 454r, perform MIMO detection on the received symbols where applicable, and provide detected symbols. A receive processor 458 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120 to a data sink 460, and provide decoded control information to a controller / processor 480.

[0072] On the uplink, at the UE 120, the transmit processor 464 may receive and process data from a data source 462 (e.g., data for a physical uplink shared channel (PUSCH)) and control information from a controller / processor 480 (e.g., control information for a physical uplink control channel (PUCCH)). The transmit processor 464 may also generate reference symbols for a reference signal (e.g., a sounding reference signal (SRS)). The symbols from the transmit processor 464 may be precoded by a TX MIMO processor 466, if applicable, further processed by demodulators 454a to 454r in the transceiver (e.g., for SC-FDM, etc.), and transmitted to the base station 110. At the BS 110, the uplink signal from the UE 120 may be received by the antenna 434, processed by the modulator 432, detected by the MIMO detector 436, if applicable, and further processed by the receive processor 438 to obtain decoded data and control information sent by the UE 120. Receive processor 438 may provide decoded data to data sink 439 and decoded control information to controller / processor 440 .

[0073] Controllers / processors 440 and 480 may direct the operation at BS 110 and UE 120, respectively. Processor 440 and / or other processors and modules at BS 110 may perform or direct the execution of processes for the techniques described herein. Memories 442 and 482 may store data and program codes for BS 110 and UE 120, respectively. Scheduler 444 may schedule UEs for data transmission on the downlink and / or uplink.

[0074] Figure 5An example system architecture 500 for interworking between a 5GS (e.g., such as distributed RAN 200) and an E-UTRAN-EPC is illustrated in accordance with certain aspects of the present disclosure. Figure 5 As shown in FIG, UE 502 may be served by separate RANs 504A and 504B controlled by separate core networks 506A and 506B, where RAN 504A provides E-UTRA services and RAN 504B provides 5G NR services. A UE may operate in only one RAN / CN or both RAN / CNs at a time.

[0075] In LTE, the basic transmission time interval (TTI) or packet duration is a 1ms subframe. In NR, a subframe is still 1ms, but the basic TTI is called a time slot. A subframe contains a variable number of time slots (e.g., 1, 2, 4, 8, 16...time slots), depending on the subcarrier spacing. NR RBs are 12 consecutive frequency subcarriers. NR can support a base subcarrier spacing of 15KHz, and other subcarrier spacings can be defined relative to the base subcarrier spacing, such as 30kHz, 60kHz, 120kHz, 240kHz, etc. The symbol and time slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing.

[0076] Figure 6 6 is a diagram showing an example of a frame format 600 for NR. The transmission timeline for each of the downlink and uplink may be divided into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 ms) and may be divided into 10 subframes with indices 0 to 9, each subframe being 1 ms. Each subframe may include a variable number of slots, depending on the subcarrier spacing. Each slot may include a variable number of symbol periods (e.g., 7 or 14 symbols), depending on the subcarrier spacing. An index may be assigned to the symbol period in each slot. A mini slot (which may be referred to as a subslot structure) refers to a transmission time interval having a duration less than a slot (e.g., 2, 3, or 4 symbols).

[0077] Each symbol in a slot may indicate a link direction (e.g., DL, UL, or flexible) for data transmission, and the link direction for each subframe may be switched dynamically. The link direction may be based on the slot format. Each slot may include DL / UL data and DL / UL control information.

[0078] In NR, a synchronization signal (SS) block is transmitted. The SS block includes PSS, SSS, and two-symbol PBCH. The SS block can be in a fixed time slot position (such as Figure 6) is transmitted in the codewords 0-3 shown in . PSS and SSS can be used by UE for cell search and acquisition. PSS can provide half-frame timing, and SS can provide CP length and frame timing. PSS and SSS can provide cell identity. PBCH carries some basic system information, such as downlink system bandwidth, timing information within a radio frame, SS burst set periodicity, system frame number, etc. SS blocks can be organized into SS bursts to support beam sweeping. Further system information (such as remaining minimum system information (RMSI), system information block (SIB), other system information (OSI)) can be transmitted on the physical downlink shared channel (PDSCH) in certain subframes. SS blocks can be transmitted up to 64 times, for example, for mmW, up to 64 different beam directions are used to transmit. Up to 64 transmissions of SS blocks are called SS burst sets. SS blocks in SS burst sets are transmitted in the same frequency region, while SS blocks in different SS burst sets can be transmitted at different frequency positions.

[0079] In some cases, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh networks, and / or various other suitable applications. In general, a sidelink signal may refer to a signal that is communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., UE or BS), even if the scheduling entity may be used for scheduling and / or control purposes. In some examples, the sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

[0080] The UE may operate in various radio resource configurations, including a configuration associated with transmitting a pilot using a dedicated resource set (e.g., a radio resource control (RRC) dedicated state, etc.), or a configuration associated with transmitting a pilot using a shared resource set (e.g., an RRC shared state, etc.). When operating in the RRC dedicated state, the UE may select a dedicated resource set for transmitting a pilot signal to the network. When operating in the RRC shared state, the UE may select a shared resource set for transmitting a pilot signal to the network. In either case, the pilot signal transmitted by the UE may be received by one or more network access devices (such as an AN, or a DU, or parts thereof). Each receiving network access device may be configured to receive and measure a pilot signal transmitted on a shared resource set, and also receive and measure a pilot signal transmitted on a dedicated resource set allocated to a UE, wherein the network access device is a member of a monitoring network access device set for the UE. One or more receiving network access devices or a CU to which the receiving network access device transmits pilot signal measurements may use these measurements to identify a serving cell of the UE or initiate a change in a serving cell for one or more UEs.

[0081] Example RACH Procedure

[0082] The Random Access Channel (RACH) is so named because it refers to a wireless channel (medium) that can be shared by multiple UEs and used by these UEs to (randomly) access the network for communication. For example, RACH can be used for call setup and access network for data transmission. In some cases, RACH can be used for initial access to the network when the UE switches from radio resource control (RRC) connected idle mode to active mode, or when switching in RRC connected mode. In addition, RACH can be used for downlink (DL) and / or uplink (UL) data arrival when the UE is in RRC idle or RRC inactive mode, and when reestablishing a connection with the network.

[0083] Figure 77 is a timing diagram (or "call flow diagram") 700 illustrating an example four-step RACH procedure in accordance with certain aspects of the present disclosure. A first message (MSG1) may be sent from UE 120 to BS 110 on a physical random access channel (PRACH). In this case, MSG1 may include only a RACH preamble. BS 110 may respond with a random access response (RAR) message (MSG2), which may include an identifier (ID) of the RACH preamble, a timing advance (TA), an uplink grant, a cell radio network temporary identifier (C-RNTI), and a backoff indicator. MSG2 may include a PDCCH communication including control information about subsequent communications on the PDSCH, as illustrated. In response to MSG2, MSG3 is transmitted from UE 120 to BS 110 on the PUSCH. MSG3 may include one or more of an RRC connection request, a tracking area update request, a system information request, a location lock or positioning signal request, or a scheduling request. BS 110 then responds with MSG4 which may include a contention resolution message.

[0084] In some cases, to speed up access, a two-step RACH procedure may be supported. As the name implies, the two-step RACH procedure effectively "collapses" the four messages of the four-step RACH procedure into two messages.

[0085] Figure 8 8 is a timing diagram 800 illustrating an example two-step RACH procedure according to certain aspects of the present disclosure. A first enhanced message (msgA) may be sent from UE 120 to BS 110. In certain aspects, msgA includes some or all of the information of MSG1 and MSG3 from the four-step RACH procedure (effectively combining MSG1 and MSG3). For example, msgA may include MSG1 and MSG3 multiplexed together, such as using one of time division multiplexing or frequency division multiplexing. In certain aspects, msgA includes a RACH preamble and a payload for random access. For example, the msgA payload may include a UE-ID and other signaling information (e.g., a buffer status report (BSR)) or a scheduling request (SR). BS 110 may respond using a random access response (RAR) message (msgB), which may effectively combine the above-mentioned MSG2 and MSG4. For example, msgB may include an ID of a RACH preamble, a timing advance (TA), a backoff indicator, a contention resolution message, a UL / DL grant, and a transmit power control (TPC) command.

[0086] In the two-step RACH procedure, msgA may include a RACH preamble and a payload. In some cases, the RACH preamble and the payload may be sent in a msgA transmission opportunity.

[0087] The random access message (msgA) transmission opportunity generally includes the msgA preamble opportunity (used to transmit the preamble signal) and the msgA payload opportunity used to transmit the PUSCH. The msgA preamble transmission generally involves:

[0088] (1) Selection of preamble sequence; and

[0089] (2) Selection of preamble opportunities (for transmitting the selected preamble sequence) in the time / frequency domain.

[0090] The msgA payload transmission generally involves:

[0091] (1) Construction of random access message payload (DMRS / PUSCH); and

[0092] (2) Selection of one or more PUSCH resource units (PRUs) in the time / frequency domain to transmit the message (payload).

[0093] In some cases, the UE monitors SSB transmissions sent (by the gNB using different beams) and associated with a limited set of time / frequency resources that define RACH occasions (ROs) and PRUs. As will be described in more detail below, upon detection of an SSB, the UE may select the RO and one or more PRUs associated with the SSB for msgA transmission. The limited set of ROs and PRUs may help reduce the monitoring overhead (blind decoding) of the base station.

[0094] There are several benefits to the two-step RACH procedure, such as access speed and the ability to send relatively small amounts of data without the overhead of the entire four-step RACH procedure to establish a connection (as the four-step RACH message may be larger than the payload).

[0095] The two-step RACH procedure may operate in any RRC state and with any supported cell size.Networks using the two-step RACH procedure may typically support contention-based random access (CBRA) message (eg, msgA) transmissions within a limited range of payload sizes and with a limited number of MCS levels.

[0096] Various technologies may be the focus of current wireless communication standards. For example, Release 15 and / or Release 16 may focus on high-end smartphones (e.g., enhanced mobile broadband (eMBB)) and other vertical markets, such as ultra-reliable low latency communications (URLLC) and / or vehicle-to-everything (V2X) communications. In some wireless communication standards (e.g., Release 17 and higher), there may be a strong desire for new radio (NR) to be scalable and deployable in a more efficient and economical manner. Therefore, a new UE type with reduced capability (RedCap) is introduced. Specifically, RedCap UEs may exhibit an overall relaxation of peak throughput, as well as lower latency and / or reliability requirements.

[0097] Therefore, some design goals for NR RedCap UEs may include scalable resource allocation, coverage enhancement for DL ​​and / or UL, power saving in all RRC states, and / or coexistence with NR High-End UEs. Fig. 9 As shown in , the NR-RedCap UE can be a smart wearable device, a sensor / camera, or any other device configured for loose Internet of Things (IoT) communications. In addition, the RedCap UE functionality and / or capabilities may overlap with the functionality and / or capabilities of Long Term Evolution (LTE) and / or fifth generation (5G) devices (e.g., high-end 5G devices). For example, the functionality of a loose IoT device may overlap with the functionality of a URLLC device, the functionality of a smart wearable device may overlap with the functionality of a low power wide area (LPWA) massive machine type communication (mMTC) device, and / or the functionality of a sensor / camera may overlap with the functionality of an eMBB device.

[0098] In some cases, one of the reduced capabilities of an NR-Lite UE is a reduced maximum bandwidth (BW) support. In Release 15 and / or Release 16, the UE may be required to support the maximum channel BW defined for the frequency band (e.g., 50 MHz for a subcarrier spacing (SCS) of 15 kHz and 100 MHz for an SCS of 30 / 60 kHz for band n78 (3300 MHz–3800 MHz). In Release 17 NR-Lite, a smaller bandwidth capability may be required (e.g., 20 MHz in frequency range FR1).

[0099] The techniques presented herein can be applied in various frequency bands used for NR. For example, for the higher frequency bands called FR4 (e.g., 52.6 GHz-114.25 GHz), OFDM waveforms with very large subcarrier spacing (960 kHz-3.84 MHz) are required to combat severe phase noise. Due to the large subcarrier spacing, the slot length tends to be very short. In the lower frequency band called FR2 (24.25 GHz to 52.6 GHz) with an SCS of 120 kHz, the slot length is 125 μSec, while in FR4 with 960 kHz, the slot length is 15.6 μSec.

[0100] Example TBS scaling and repetition indication for Msg4 PDSCH

[0101] Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques and mechanisms for indicating transmission parameters (such as TBS scaling and / or repetition) for Msg4PDSCH. The transmission parameters may be selected to enhance reliability for UEs with limited capabilities (such as RedCap UEs).

[0102] The techniques presented herein can be used in certain candidate traffic scenarios, for example, scenarios involving devices with reduced capabilities (e.g., NR lightweight devices). Such devices include those used in industrial wireless sensors, video surveillance, and smart wearable devices.

[0103] In some cases, in order to support devices with different capabilities, different modulation and coding scheme (MCS) tables may be supported. For example, for an MCS with the highest modulation order 64QAM, a conventional MCS table ( Fig. 10A shown) and low SE MCS table ( Fig. 10B shown).

[0104] Fig. 10A The rule table of is specified in Release 15 and can be regarded as a basic MCS table, which is considered mandatory for NRUE. Fig. 10B The Low SE table (added later in Release 16 to support URLLC features for higher transmission reliability) is considered optional for NR UEs. In addition, another MCS table with the highest modulation order 256QAM is also considered mandatory for Release 15 / 16 UEs, but may not be supported by RedCap UEs because the maximum mandatory modulation for RedCap UEs may be relaxed to 64QAM.

[0105] In 5G NR, repeated transmission of PDSCH on consecutive time slots (also called slot repetition / aggregation, or multi-slot PDSCH) is supported, such as Fig.11In this case, the MCS and resource allocation may be indicated in the scheduling DCI and shared over consecutive time slots.

[0106] For each slot of a multi-slot PDSCH, the transport block (TB) is the same, but the coded bits may be different because the redundancy version (RV) for each slot may be different. The RV for the first slot may be indicated in the scheduling DCI, while the RV for the nth slot is determined by "n mod 4". Fig.11 For the 4-slot PDSCH example shown, an exemplary RV sequence over a slot may be {RV0, RV2, RV3, RV1} for a new transmission and {RV3, RV1, RV0, RV 2} for a retransmission.

[0107] Transmission reliability during initial access is often a bottleneck for coverage, which may become more critical for RedCap UEs with smaller BW support and reduced number of antennas. To improve transmission reliability, transport block size (TBS) scaling for lower code rates (where the scaling factor is < 1), or repeated transmissions may be used. In some systems, TBS scaling may be supported for some random access channel (RACH) messages (such as Msg 2PDSCH), where a dedicated TBS scaling field is indicated in the scheduling DCI (e.g., indicated by the CRC of the RA-RNTI mask). Fig.12 A table illustrating example TBS scaling factors that may be signaled via the TBS scaling field (of the scheduling DCI).

[0108] Aspects of the present disclosure provide additional techniques and mechanisms for indicating transmission parameters (such as TBS scaling and / or repetition) for other types of RACH messages (such as Msg4PDSCH), which can help enhance reliability for UEs with limited capabilities, such as RedCap UEs. These techniques can help support RedCap UEs that may not support a sufficiently large TBS (e.g., 130 bytes) for Msg4 with a small scaling factor (e.g., 0.25) in a single slot.

[0109] Fig.13 is a flow diagram illustrating example operations 1300 for wireless communications in accordance with certain aspects of the present disclosure. For example, operations 1300 may be performed by a UE (such as, for example, UE 120a in wireless communication network 100) to determine a TBS scaling and / or repetition factor for a Msg4 PDSCH.

[0110] Operations 1300 begin, at 1302, by indicating to a network entity at least one of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE.

[0111] At 1304, the UE determines, as part of a random access channel (RACH) procedure, one or more transmission parameters for achieving a reduced code rate applicable to the limited capability of the UE for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message.

[0112] At 1306, the UE processes the PDSCH according to the determined transmission parameters.

[0113] Fig.14 is a flow chart illustrating example operations 1400 for wireless communications by a network entity and may be considered similar to Fig.13 For example, operation 1400 may be performed by BS 110 to provide a method for performing Fig.13 The UE of operation 1300 instructs TBS scaling and / or repetition.

[0114] Operations 1400 begin, at 1402, by receiving from a user equipment (UE) an indication of at least one of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE.

[0115] At 1404, the network entity determines, as part of a RACH procedure, one or more transmission parameters for implementing a reduced code rate applicable to the limited capability of the UE for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message.

[0116] At 1406, the network entity transmits the PDSCH to the UE according to the determined transmission parameters.

[0117] Various approaches may be used to indicate transmission parameters (eg, TBS scaling and / or repetition factor) for Msg4 PDSCH.

[0118] For example, in some cases, the TBS scaling factor indicated for Msg4 PDSCH is the same as the TBS scaling factor indicated for Msg2 PDSCH. In this case, the UE may apply the same TBS scaling factor as indicated in the scheduling DCI of the Msg2 PDSCH.

[0119] In some cases, one or more (N) reserved bits of the Msg2 scheduling DCI may be used as an indication of transmission parameters (e.g., TBS scaling and / or repetition factor) for the Msg4 PDSCH, such as Fig.15 shown.

[0120] In some cases, the bits of one or more fields of Msg4 Scheduling DCI may be used as an indication of transmission parameters, such as Fig.16 For example, the Downlink Assignment Index (DAI) field (in Fig.16 2A) and / or the MCS field (in Fig.16 One or more bits of the MCS field (marked as 2B in the figure) may be re-used. In some cases, the re-used bits of the MCS field may be the most significant bits (MSBs) because only low MCS values ​​may be required due to higher reliability requirements of the transmission. Examples of other fields (bits) that may be re-used include one or a combination of HARQ process ID, TPC (transmit power control) for PUCCH, PUCCH resource indicator, or PDSCH-to-HARQ_feedback timing indicator.

[0121] In some cases, the associated indications of TPC, PUCCH resource indicator, and / or PDSCH to HARQ feedback timing indicator may instead be carried in the Msg4 PDSCH, rather than in its scheduling PDCCH. This may allow these bits to be repurposed, and such an approach may be motivated by the potential to free up more bits for these indications, e.g., using the PUCCH resource indicator if PUCCH repetitions for HARQ feedback are required, and / or using bits of the PDSCH to HARQ feedback timing indicator if timeline relaxation for HARQ feedback allows for more possible PDSCH to HARQ feedback offsets. It is also possible that TPC for PUCCH may not be required for deterministic full power transmission for HARQ feedback PUCCH.

[0122] The UE has various options to indicate its support for the transmission parameter signaling proposed in this document. For example, according to one option, the UE can report reduced capability or request coverage enhancement via Msg1 (RACH preamble). According to another option, the UE can report reduced capability or request coverage enhancement via Msg3. In addition to reporting reduced capability or requesting coverage enhancement, the UE can also transmit a channel state information (CSI) report in Msg3, which can help the gNB determine the TBS scaling factor and / or repetition number for Msg4.

[0123] In some cases, the gNB may indicate to the UE via a SIB (e.g., SIB1) whether the low CE MCS table for Msg4 is enabled or disabled. If enabled by the gNB, the UE may indicate its capability for Msg4 (e.g., for Msg4) via a RACH preamble (Msg1) or Msg3. Fig. 10B Low SE MCS shown in the table).

[0124] In some cases, the gNB may further indicate via Msg4 DCI whether the low SE MCS table is used for Msg4 PDSCH (and / or repeated). Fig.17 As shown, according to the first alternative (Alt1), the bits in the DAI field in Msg4 can be used to indicate repetition (which can be associated with a regular MCS table or a low SE MCS table). Fig.17 As shown, according to the second alternative (Alt 2), the diverted bits may be used to jointly indicate the MCS table and repetition.

[0125] Fig.18 The following describes operations that may include being configured to perform the techniques disclosed herein (such as Fig.13 1800 includes a communication device 1800 that includes various components (e.g., corresponding to means-plus-function components) of the operations illustrated in 1802. The communication device 1800 includes a processing system 1802 coupled to a transceiver 1808. The transceiver 1808 is configured to transmit and receive signals (such as the various signals described herein) for the communication device 1800 via an antenna 1810. The processing system 1802 may be configured to perform processing functions for the communication device 1800, including processing signals received and / or to be transmitted by the communication device 1800.

[0126] The processing system 1802 includes a processor 1804 coupled to a computer-readable medium / memory 1812 via a bus 1806. In some aspects, the computer-readable medium / memory 1812 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1804, cause the processor 1804 to perform Fig.13, or other operations for performing the various techniques discussed herein. In some aspects, the computer-readable medium / memory 1812 stores code 1814 for indicating to a network entity at least one of the limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; code 1816 for determining, as part of a random access channel (RACH) procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for implementing a reduced code rate applicable to the limited capabilities of the UE; and code 1818 for processing the PDSCH according to the determined transmission parameters. In some aspects, the processor 1804 has a circuit system configured to implement the code stored in the computer-readable medium / memory 1812. Processor 1804 includes: a circuit system 1820 for indicating to a network entity at least one of the limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; a circuit system 1822 for determining, as part of a random access channel (RACH) procedure, one or more transmission parameters for implementing a reduced code rate applicable to the limited capabilities of the UE for a subsequent random access (RA) message of a physical downlink shared channel (PDSCH) received after a random access response (RAR) message; and a circuit system 1824 for processing the PDSCH based on the determined transmission parameters.

[0127] Fig.19 The following describes operations that may include being configured to perform the techniques disclosed herein (such as Fig.14 1900 includes a communication device 1900 that includes various components (e.g., corresponding to means-plus-function components) of the operations illustrated in 1902. The communication device 1900 includes a processing system 1902 coupled to a transceiver 1908. The transceiver 1908 is configured to transmit and receive signals (such as the various signals described herein) for the communication device 1900 via an antenna 1910. The processing system 1902 may be configured to perform processing functions for the communication device 1900, including processing signals received and / or to be transmitted by the communication device 1900.

[0128] The processing system 1902 includes a processor 1904 coupled to a computer-readable medium / memory 1912 via a bus 1906. In some aspects, the computer-readable medium / memory 1912 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1904, cause the processor 1904 to perform Fig.14, or other operations for performing the various techniques discussed herein. In certain aspects, the computer-readable medium / memory 1912 stores code 1914 for receiving from a user equipment (UE) at least one of an indication of a limited capability of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capability of the UE; code 1916 for determining, as part of a RACH procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for implementing a reduced code rate applicable to the limited capability of the UE; and code 1918 for transmitting the PDSCH to the UE according to the determined transmission parameters. In certain aspects, the processor 1904 has a circuit system configured to implement the code stored in the computer-readable medium / memory 1912. Processor 1904 includes: a circuit system 1920 for receiving, from a user equipment (UE), an indication of at least one of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; a circuit system 1922 for determining, as part of a RACH procedure, one or more transmission parameters for implementing a reduced code rate applicable to the limited capabilities of the UE for a subsequent random access (RA) message of a physical downlink shared channel (PDSCH) received after a random access response (RAR) message; and a circuit system 1924 for transmitting the PDSCH to the UE based on the determined transmission parameters.

[0129] Additional considerations

[0130] The techniques described herein may be used for various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and other networks. The terms "network" and "system" are often used interchangeably. A CDMA network may implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, and the like. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95, and IS-856 standards. A TDMA network may implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are parts of Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are versions of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). NR is an emerging wireless communication technology under development.

[0131] The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, although various aspects may be described herein using terms commonly associated with 3G, 4G and / or 5G wireless technologies, various aspects of the present disclosure may be applied in communication systems based on other generations.

[0132] In 3GPP, the term "cell" may refer to the coverage area of ​​a B node (NB) and / or a NB subsystem serving the coverage area, depending on the context in which the term is used. In NR systems, the terms "cell" and BS, next-generation B node (gNB or g B node), access point (AP), distributed unit (DU), carrier, or transmission reception point (TRP) may be used interchangeably. The BS may provide communication coverage for macro cells, pico cells, femto cells, and / or other types of cells. A macro cell may cover a relatively large geographic area (e.g., a radius of several thousand meters) and may allow unrestricted access by UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs of users in a residence, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS.

[0133] UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, customer premises equipment (CPE), cellular phone, smart phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, wireless local loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or medical equipment, biometric sensor / device, wearable device (such as smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), transportation component or sensor, smart meter / sensor, industrial manufacturing equipment, global positioning system device, or any other suitable device configured to communicate via wireless or wired medium. Some UEs may be considered machine type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which can communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node can provide connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices.

[0134] Some wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also often referred to as frequency modulation, frequency bins, etc. Each subcarrier can be modulated with data. In general, modulation symbols are sent in the frequency domain for OFDM and in the time domain for SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the spacing of subcarriers can be 15kHz, and the minimum resource allocation (called a "resource block" (RB)) can be 12 subcarriers (or 180kHz). Therefore, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal fast Fourier transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth may also be divided into subbands. For example, a subband may cover 1.08 MHz (e.g., 6 RBs), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe.

[0135] NR can utilize OFDM with CP on the uplink and downlink and includes support for half-duplex operation using TDD. In NR, a subframe is still 1ms, but the basic TTI is called a time slot. A subframe contains a variable number of time slots (e.g., 1, 2, 4, 8, 16...time slots), depending on the subcarrier spacing. NR RB is 12 consecutive frequency subcarriers. NR can support a base subcarrier spacing of 15KHz, and other subcarrier spacings can be defined relative to the base subcarrier spacing, such as 30kHz, 60kHz, 120kHz, 240kHz, etc. The symbol and time slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming can be supported and the beam direction can be dynamically configured. MIMO transmission with precoding can also be supported. In some examples, the MIMO configuration in the DL can support up to 8 transmit antennas (multi-layer DL transmission with up to 8 streams) and up to 2 streams per UE. In some examples, multi-layer transmission of up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported using up to 8 serving cells.

[0136] In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., BS) allocates resources for communication between some or all devices and equipment within its service area or cell. A scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communications, subordinate entities utilize resources allocated by the scheduling entity. A base station is not the only entity that can be used as a scheduling entity. In some examples, a UE may act as a scheduling entity, and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and other UEs may utilize resources scheduled by the UE for wireless communication. In some examples, a UE may act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In a mesh network example, UEs may communicate directly with each other in addition to communicating with a scheduling entity.

[0137] In some examples, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh networks, and / or various other suitable applications. In general, a sidelink signal may refer to a signal that is communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., UE or BS), even if the scheduling entity may be used for scheduling and / or control purposes. In some examples, the sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum).

[0138] Each method disclosed herein includes one or more steps or actions for implementing the method. These method steps and / or actions can be interchangeable with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of specific steps and / or actions can be changed without departing from the scope of the claims.

[0139] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single members. As an example, "at least one of a, b, or c" is intended to cover: a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other ordering of a, b, and c).

[0140] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" may include calculating, computing, processing, deriving, investigating, searching (e.g., searching in a table, a database, or another data structure), ascertaining, and the like. Also, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Also, "determining" may include resolving, selecting, choosing, establishing, and the like.

[0141] The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be easily understood by those skilled in the art, and the universal principles defined herein can be applied to other aspects. Thus, the claims are not intended to be limited to the various aspects shown herein, but should be granted the full scope consistent with the language of the claims, wherein the singular reference to the element is not intended to mean "there is and only one" (unless specifically stated) but "one or more". Unless otherwise specifically stated, the term "some / some" refers to one or more. The elements of the various aspects described throughout this disclosure are all structural and functional equivalents currently or hereafter known to ordinary technicians in the art and are explicitly incorporated herein by reference, and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be donated to the public, regardless of whether such disclosure is explicitly recorded in the claims. Any element of the claim should not be interpreted under the provisions of 35 U.S.C. § 112 (f), unless the element is explicitly stated using the phrase "device for..." or in the case of a method claim, the element is stated using the phrase "step for...".

[0142] The various operations of the methods described above may be performed by any suitable device capable of performing the corresponding functions. These devices may include various hardware and / or software components and / or modules, including but not limited to circuits, application specific integrated circuits (ASICs), or processors. Generally, where there are operations illustrated in the accompanying drawings, these operations may have corresponding paired device-plus-function components with similar numbers.

[0143] The various illustrative logical blocks, modules, and circuits described in conjunction with the present disclosure may be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0144] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link together various circuits including a processor, a machine-readable medium, and a bus interface. The bus interface may be used to connect a network adapter, etc., to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the user terminal 120 (see Figure 1 ), a user interface (e.g., a keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art and will not be described further. The processor may be implemented with one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuit systems capable of executing software. Those skilled in the art will recognize how to best implement the functionality described with respect to the processing system, depending on the specific application and the overall design constraints imposed on the overall network or system.

[0145] If implemented in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or other. Computer-readable media include both computer storage media and communication media, which include any media that facilitate the transfer of computer programs from one place to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. A computer-readable storage medium may be coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. As an example, a machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium having instructions stored thereon that is separated from a wireless node, all of which may be accessed by a processor through a bus interface. Alternatively or additionally, a machine-readable medium or any part thereof may be integrated into a processor, such as a cache and / or a general register file, which may be the case. As an example, examples of machine-readable storage media may include RAM (random access memory), flash memory, ROM (read only memory), PROM (programmable read only memory), EPROM (erasable programmable read only memory), EEPROM (electrically erasable programmable read only memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage media, or any combination thereof. Machine-readable media may be implemented in a computer program product.

[0146] A software module may include a single instruction, or many instructions, and may be distributed over several different code segments, between different programs, and across multiple storage media. A computer-readable medium may include multiple software modules. These software modules include instructions that cause a processing system to perform various functions when executed by an apparatus such as a processor. These software modules may include a transmission module and a reception module. Each software module may reside in a single storage device or may be distributed across multiple storage devices. As an example, when a triggering event occurs, a software module may be loaded into a RAM from a hard drive. During the execution of a software module, a processor may load some instructions into a cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When describing the functionality of a software module as described below, it will be understood that such functionality is implemented by the processor when the processor executes instructions from the software module.

[0147] Likewise, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technology (such as infrared (IR), radio, and microwave), then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology (such as infrared, radio, and microwave) is included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Disks, where disks often reproduce data magnetically, and discs reproduce data optically with lasers. Thus, in some aspects, computer-readable media may include non-transitory computer-readable media (e.g., tangible media). Additionally, for other aspects, computer-readable media may include transient computer-readable media (e.g., signals). Combinations of the above should also be included within the scope of computer-readable media.

[0148] Thus, certain aspects may include a computer program product for performing the operations presented herein. For example, such a computer program product may include a computer-readable medium having stored (and / or encoded) thereon instructions that can be executed by one or more processors to perform the operations described herein, such as for performing the operations described herein and in Fig.13 Or instructions for the operations explained in 14.

[0149] In addition, it should be appreciated that modules and / or other appropriate means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by a user terminal and / or base station where applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or a floppy disk, etc.) so that once the storage device is coupled to or provided to a user terminal and / or base station, the device can obtain the various methods. In addition, any other suitable technology suitable for providing the methods and techniques described herein to a device may be utilized.

[0150] It will be understood that the claims are not limited to the precise configuration and components illustrated above. Various changes, substitutions and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.

Claims

1. An apparatus for wireless communication by a user equipment (UE), comprising: at least one processor and a memory, the at least one memory and the processor being configured to: indicating to a network entity at least one of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; determining, as part of a random access channel (RACH) procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for achieving a reduced code rate applicable to the restricted capabilities of the UE; as well as processing the PDSCH according to the determined transmission parameters, The transmission parameter is indicated via downlink control information (DCI) scheduling the RAR message or via DCI scheduling the PDSCH.

2. The device of claim 1, wherein: The transmission parameters include at least one of a transport block size (TBS) scaling factor or a repetition factor to be applied to the PDSCH; as well as The TBS scaling factor or repetition factor is indicated via the DCI scheduling the RAR message.

3. The device of claim 2, wherein: The DCI scheduling the RAR message indicates the same TBS scaling as used for the RAR message for the PDSCH.

4. The apparatus of claim 3, wherein the DCI that schedules the RAR message comprises one or more bits, the one or more bits indicating at least one of the TBS scaling factor or repetition used for the PDSCH by reusing one or more bits of the reserved bits of the DCI that schedules the RAR message.

5. The device of claim 1, wherein: The transmission parameters include a transport block size (TBS) scaling factor to be applied to the PDSCH; and The TBS scaling factor is indicated via the DCI scheduling the PDSCH.

6. The apparatus of claim 5, wherein the indication is provided via at least one of: one or more bits of a downlink assignment index (DAI) field or one or more bits of a modulation and coding scheme (MCS) field of the DCI.

7. The apparatus of claim 1 , wherein the transmission parameter comprises at least one of a transport block size (TBS) scaling factor or a repetition factor to be applied to the PDSCH and is indicated by diverting bits of one or more of the following of the DCI: Hybrid Automatic Repeat Request (HARQ) process ID; Transmit power control (TPC) of a physical uplink control channel (PUCCH) for providing HARQ feedback for the PDSCH; a resource indicator for the PUCCH; or A timing indicator is used to provide the HARQ feedback.

8. The apparatus of claim 6, wherein the PDSCH indicates one or more of: Transmit power control (TPC) of a physical uplink control channel (PUCCH) for providing HARQ feedback for the PDSCH; a resource indicator for the PUCCH; or A timing indicator is used to provide the HARQ feedback.

9. The apparatus of claim 1, wherein the UE indicates at least one of its limited capability or the request for coverage enhancement via a random access channel (RACH) preamble message.

10. The apparatus of claim 1, wherein the UE indicates at least one of its limited capabilities or the request for coverage enhancement via an uplink message sent after receiving the RAR message.

11. The apparatus of claim 10, wherein the UE further provides channel state information (CSI) in the uplink message.

12. The apparatus of claim 1, the at least one processor and memory being further configured to receive an indication from the network entity to enable or disable use of a low spectral efficiency (SE) modulation and coding scheme (MCS) table for the PDSCH.

13. The apparatus of claim 12, the at least one processor and memory further configured to indicate a capability of the UE to support the low SE MCS table for the PDSCH.

14. The apparatus of claim 12, wherein the indication is provided via a system information block (SIB).

15. The apparatus of claim 12, wherein the indication is provided via a DCI scheduling the PDSCH.

16. The apparatus of claim 15, wherein the indication is provided via one or more bits of a downlink assignment index (DAI) field, the one or more bits of the downlink assignment index (DAI) field being diverted to at least one of: indicating a repetition associated with a regular MCS table or the low SE MCS table; or The repetition and which of the normal MCS table or the low SE MCS table to use are jointly indicated.

17. An apparatus for wireless communication by a network entity, comprising: at least one processor and memory, the at least one processor and memory configured to: receiving, from a user equipment (UE), at least one of an indication of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; determining, as part of the RACH procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for achieving a reduced code rate applicable to the restricted capabilities of the UE; as well as transmitting the PDSCH to the UE according to the determined transmission parameters, The transmission parameter is indicated via downlink control information (DCI) scheduling the RAR message or via DCI scheduling the PDSCH.

18. The apparatus of claim 17, wherein: The transmission parameters include at least one of a transport block size (TBS) scaling factor or a repetition factor to be applied to the PDSCH; and The TBS scaling factor or repetition factor is indicated via the DCI scheduling the RAR message.

19. The apparatus of claim 18, wherein: The DCI scheduling the RAR message indicates the same TBS scaling as used for the RAR message for the PDSCH.

20. The apparatus of claim 19, wherein the DCI that schedules the RAR message comprises one or more bits, the one or more bits indicating the at least one of the TBS scaling factor or repetition used for the PDSCH by reusing one or more of the reserved bits of the DCI that schedules the RAR message.

21. The apparatus of claim 17, wherein: The transmission parameters include a transport block size (TBS) scaling factor to be applied to the PDSCH; and The TBS scaling factor is indicated via the DCI scheduling the PDSCH.

22. The apparatus of claim 21, wherein the indication is provided via at least one of: one or more bits of a downlink assignment index (DAI) field or one or more bits of a modulation and coding scheme (MCS) field of the DCI.

23. The apparatus of claim 17, wherein the transmission parameter comprises at least one of a transport block size (TBS) scaling factor or a repetition factor to be applied to the PDSCH and is indicated by diverting bits of one or more of the following of the DCI: Hybrid Automatic Repeat Request (HARQ) process ID; Transmit power control (TPC) of a physical uplink control channel (PUCCH) for providing HARQ feedback for the PDSCH; a resource indicator for the PUCCH; or A timing indicator is used to provide the HARQ feedback.

24. The apparatus of claim 22, wherein the PDSCH indicates one or more of: Transmit power control (TPC) of a physical uplink control channel (PUCCH) for providing HARQ feedback for the PDSCH; a resource indicator for the PUCCH; or A timing indicator is used to provide the HARQ feedback.

25. The apparatus of claim 17, wherein the UE indicates at least one of its limited capability or the request for coverage enhancement via a random access channel (RACH) preamble message.

26. The apparatus of claim 17, wherein the UE indicates at least one of its limited capabilities or the request for coverage enhancement via an uplink message sent after receiving the RAR message.

27. The apparatus of claim 26, wherein the UE further provides channel state information (CSI) in the uplink message.

28. The apparatus of claim 17, the at least one processor and memory being further configured to send an indication to the UE to enable or disable use of a low spectral efficiency (SE) modulation and coding scheme (MCS) table for the PDSCH.

29. The apparatus of claim 28, the at least one processor and memory further configured to receive, from the UE, an indication of the UE's ability to support the low SE MCS table for the PDSCH.

30. The apparatus of claim 28, wherein the indication is sent via a system information block (SIB).

31. The apparatus of claim 28, wherein the indication is sent via a DCI scheduling the PDSCH.

32. The apparatus of claim 31 , wherein the indication is provided via one or more bits of a downlink assignment index (DAI) field, the one or more bits of the downlink assignment index (DAI) field being diverted to at least one of: indicating a repetition associated with a regular MCS table or the low SE MCS table; or The repetition and which of the normal MCS table or the low SE MCS table to use are jointly indicated.

33. A method for wireless communication by a user equipment (UE), comprising: indicating to a network entity at least one of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; determining, as part of a random access channel (RACH) procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for achieving a reduced code rate applicable to the restricted capabilities of the UE; as well as processing the PDSCH according to the determined transmission parameters, The transmission parameter is indicated via downlink control information (DCI) scheduling the RAR message or via DCI scheduling the PDSCH.

34. A method for wireless communication by a network entity, comprising: receiving, from a user equipment (UE), at least one of an indication of limited capabilities of the UE or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; determining, as part of the RACH procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for achieving a reduced code rate applicable to the restricted capabilities of the UE; as well as transmitting the PDSCH to the UE according to the determined transmission parameters, The transmission parameter is indicated via downlink control information (DCI) scheduling the RAR message or via DCI scheduling the PDSCH.

35. A computer readable medium having stored thereon instructions for: indicating to a network entity at least one of limited capabilities of a user equipment (UE) or a request for coverage enhancement of a random access channel (RACH) procedure applicable to the limited capabilities of the UE; determining, as part of a random access channel (RACH) procedure, for a physical downlink shared channel (PDSCH) subsequent random access (RA) message received after a random access response (RAR) message, one or more transmission parameters for achieving a reduced code rate applicable to the restricted capabilities of the UE; as well as processing the PDSCH according to the determined transmission parameters, The transmission parameter is indicated via downlink control information (DCI) scheduling the RAR message or via DCI scheduling the PDSCH.

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