Message 2 PDSCH repetition based on multi-segment RAR window

Abstract

Various aspects of improving RAR coverage by RAR PDSCH repetition are provided. A UE is configured to transmit a preamble to a BS for initiating a RACH procedure. The BS is configured to transmit a first RAR to the UE during a first portion of a RAR window in response to receiving the preamble. The BS is configured to determine that an RRC connection request in response to the transmitted first RAR is not received. The BS is configured to transmit a first plurality of RARs to the UE in a first plurality of time slots during a second portion of the RAR window following the first portion of the RAR window upon determining that an RRC connection request in response to the transmitted first RAR is not received. The UE is configured to receive a plurality of RARs from the BS in response to the transmitted preamble.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 952,001, filed on December 20, 2019, entitled “MESSAGE 2 PDSCH REPETITION BASED ON MULTI-SEGMENT RAR WINDOW,” and U.S. Patent Application No. 17 / 107,626, filed on November 30, 2020, entitled “MESSAGE 2 PDSCH REPETITION BASED ON MULTI-SEGMENT RAR WINDOW,” the disclosures of which are expressly incorporated herein by reference in their entirety. background Technical Field

[0004] The present disclosure relates generally to communication systems, and more particularly to message 2 (msg2) random access channel (RACH) response (RAR) physical downlink shared channel (PDSCH) repetition based on a multi-segment RAR window.

[0005] introduction

[0006] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0007] 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. An example telecommunication standard is 5G New Radio (NR). 5G NR is a part of the continuous mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)) and other requirements. 5GNR includes services associated with enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). Some aspects of 5G NR can be based on 4G Long Term Evolution (LTE) standards. There is a need for further improvements to 5G NR technology. These improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies.

[0008] Overview

[0009] A brief summary of one or more aspects is given below to provide a basic understanding of such aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be presented later.

[0010] In one aspect of the present disclosure, a method, a computer readable medium, and an apparatus are provided. The apparatus may be a device at a UE. The apparatus may be a processor and / or a modem at a user equipment (UE) or the UE itself. The apparatus is configured to transmit a preamble for initiating a RACH procedure to a base station. In addition, the apparatus is configured to receive a plurality of RARs in response to the transmitted preamble from the base station. The plurality of RARs are received in a plurality of time slots during a portion of a RAR window.

[0011] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be an apparatus at a base station (BS). The apparatus may be a processor and / or a modem at the BS or the BS itself. The apparatus is configured to receive a preamble for initiating a RACH procedure from a UE. In addition, the apparatus is configured to transmit a first RAR to the UE in response to receiving the preamble. The first RAR is transmitted during a first portion of the RAR window. In addition, the apparatus is configured to determine that a radio resource control (RRC) connection request in response to the transmitted first RAR is not received. In addition, the apparatus is configured to transmit a first plurality of RARs to the UE in a first plurality of time slots during a second portion of the RAR window after the first portion of the RAR window when it is determined that an RRC connection request in response to the transmitted first RAR is not received.

[0012] To achieve the foregoing and related ends, the one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are merely indicative of several of the various ways in which the principles of the various aspects may be employed, and this description is intended to cover all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0015] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0016] Figure 2B is a diagram illustrating an example of DL channels within a subframe according to various aspects of the present disclosure.

[0017] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0018] Figure 2D is a diagram illustrating an example of UL channels within a subframe according to various aspects of the present disclosure.

[0019] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0020] Figure 4 This is a call flow diagram explaining msg2 RAR PDSCH repetition.

[0021] Figure 5A is a first diagram illustrating msg2 RAR PDSCH repetition.

[0022] Figure 5B is a second diagram illustrating msg2 RAR PDSCH repetition.

[0023] Figure 6 is a flow chart of a wireless communication method associated with a UE.

[0024] Figure 7 is a flow chart of a wireless communication method associated with a BS.

[0025] Figure 8 is a diagram illustrating an example of a hardware implementation for an example device.

[0026] Fig. 9 is a diagram illustrating another example of a hardware implementation for another example device.

[0027] Detailed Description

[0028] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. This detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid diluting such concepts.

[0029] Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0030] As an example, an element, or any part of an element, or any combination of elements may be implemented as a "processing system" including one or more processors. Examples of processors include: microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform various functionalities described throughout this disclosure. One or more processors in a processing system may execute software. Software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether it is described in software, firmware, middleware, microcode, hardware description languages, or other terms.

[0031] Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, each function may be stored or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of the aforementioned types of computer-readable media, or any other medium that can be used to store instructions or data structures in the form of computer executable code that can be accessed by a computer.

[0032] Figure 1 1 is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0033] The base station 102 configured for 4G Long Term Evolution (LTE), collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), can interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). The base station 102 configured for 5G New Radio (NR), collectively referred to as the Next Generation RAN (NG-RAN), can interface with the core network 190 via a second backhaul link 184. The base station 102 can also perform one or more of the following functions, among other functions: delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 may communicate with each other directly or indirectly (eg, through the EPC 160 or the core network 190) over a third backhaul link 134 (eg, an X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

[0034] Base stations 102 may communicate wirelessly with UEs 104. Each base station 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). A communication link 120 between a base station 102 and a UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. These communication links may be through one or more carriers. For each carrier allocated in a carrier aggregation of up to Yx MHz (x component carriers) for transmission in each direction, the base station 102 / UE104 may use a spectrum of up to Y megahertz (MHz) (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) bandwidth. These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated to DL compared to UL). The component carrier may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carrier may be referred to as a secondary cell (SCell).

[0035] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

[0036] The wireless communication system may further include a Wi-Fi access point (AP) 150 in communication with a Wi-Fi station (STA) 152 via a communication link 154, such as in a 5 gigahertz (GHz) unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) to determine whether the channel is available prior to communication.

[0037] The small cell 102' may operate in a licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' may employ NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) as used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum may boost the coverage of the access network and / or increase the capacity of the access network.

[0038] The electromagnetic spectrum is typically subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz–7.125 GHz) and FR2 (24.25 GHz–52.6 GHz). Frequencies between FR1 and FR2 are typically referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is typically (interchangeably) referred to as the “sub-6 GHz band” in various documents and articles. Similar naming issues sometimes arise regarding FR2, which is typically (interchangeably) referred to as the “millimeter wave” band in various documents and articles, although it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified as the “millimeter wave” band by the International Telecommunication Union (ITU).

[0039] In view of the above aspects, unless otherwise specifically stated, it should be understood that if used in this document, the term sub-"6GHz" and the like can broadly refer to frequencies that can be less than 6GHz, can be within FR1, or can include mid-band frequencies. In addition, unless otherwise specifically stated, it should be understood that if used in this document, the term "millimeter wave" and the like can broadly refer to frequencies that can include mid-band frequencies, can be within FR2, or can be within the EHF band.

[0040] Whether a small cell 102' or a large cell (e.g., a macro base station), the base station 102 may include and / or be referred to as an eNB, a gB node (gNB), or another type of base station. Some base stations (such as gNB 180) may operate in the traditional sub-6 GHz spectrum, in millimeter wave frequencies, and / or near millimeter wave frequencies to communicate with UE 104. When gNB 180 operates in millimeter wave frequencies or near millimeter wave frequencies, gNB 180 may be referred to as a millimeter wave base station. Millimeter wave base station 180 may utilize beamforming 182 with UE 104 to compensate for path loss and short range. Base station 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays to facilitate beamforming.

[0041] Base station 180 may transmit beamformed signals to UE 104 in one or more transmit directions 182'. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182". UE 104 may also transmit beamformed signals to base station 180 in one or more transmit directions. Base station 180 may receive beamformed signals from UE 104 in one or more receive directions. Base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of base station 180 / UE 104. The transmit direction and receive direction of base station 180 may be the same or may be different. The transmit direction and receive direction of UE 104 may be the same or may be different.

[0042] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, an MBMS gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may be in communication with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are delivered through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area that broadcasts a specific service, and may be responsible for session management (start / stop) and for collecting eMBMS-related charging information.

[0043] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. AMF 192 may be in communication with a unified data management (UDM) 196. AMF 192 is a control node that handles signaling between UE 104 and the core network 190. In general, AMF 192 provides quality of service (QoS) flow and session management. All user IP packets are delivered through UPF 195. UPF 195 provides UE IP address allocation and other functions. UPF 195 is connected to IP service 197. IP service 197 may include Internet, intranet, IMS, packet switching (PS) streaming service, and / or other IP services.

[0044] A base station may include and / or be referred to as a gNB, a Node B, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmission reception point (TRP), or some other suitable term. The base station 102 provides an access point to the EPC 160 or the core network 190 for the UE 104. Examples of UE 104 include a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet device, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a health care device, an implant, a sensor / actuator, a display, or any other similar functional device. Some UEs 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, ovens, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0045] Although the present disclosure may focus on 5G NR, the concepts and aspects described herein may be applicable to other similar areas such as LTE, Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), or other wireless / radio access technologies.

[0046] Refer again Figure 1 In certain aspects, both UE 104 and base station 180 may be configured for msg2 RARPDSCH duplication handling, as described below with respect to Figure 4 , 5A , 5B, 6, 7 (198) discussed.

[0047] Figure 2A 200 is a diagram illustrating an example of a first subframe within a 5G / NR frame structure. Figure 2B FIG230 is a diagram illustrating an example of DL channels within a 5G / NR subframe. Figure 2C 250 is a diagram illustrating an example of a second subframe within a 5G / NR frame structure. Figure 2D280 is a diagram illustrating an example of an UL channel within a 5G / NR subframe. The 5G / NR frame structure can be frequency division duplex (FDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to either DL or UL; or can be time division duplex (TDD), where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL. Figure 2A , 2C In the example provided, the 5G / NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly DL) and subframe 3 is configured with slot format 34 (mostly UL), where D is DL, U is UL, and F is for flexible use between DL / UL. Although subframes 3 and 4 are shown as having slot formats 34 and 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mixture of DL, UL, and flexible symbols. The UE is configured with a slot format (dynamically configured by DL control information (DCI) or semi-statically / statically configured by radio resource control (RRC) signaling) through the received slot format indicator (SFI). Note that the following description also applies to the 5G / NR frame structure for TDD.

[0048] Other wireless communication technologies may have different frame structures and / or different channels. A frame (e.g., a 10 millisecond (ms) frame) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. A subframe may also include a mini-time slot, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. The symbols on the DL may be cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots within a subframe is based on the time slot configuration and parameter design. For slot configuration 0, different parameter designs μ of 0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For slot configuration 1, different parameter designs 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Accordingly, for slot configuration 0 and parameter design μ, there are 14 symbols per slot and 2 per subframe. μ time slots. The subcarrier spacing and symbol length / duration vary depending on parameter design. The subcarrier spacing can be equal to 2 μ*15 kilohertz (kHz), where μ is parameter design 0 to 4. Thus, parameter design μ=0 has a subcarrier spacing of 15 kHz, while parameter design μ=4 has a subcarrier spacing of 240 kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A-2D An example of a slot configuration 0 with 14 symbols per slot and a parameter design μ=2 with 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is about 16.67 μs. Within a frame set, there may be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP may have a specific parameter design.

[0049] A resource grid may be used to represent the frame structure. Each slot includes a resource block (RB) (also called a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a number of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0050] like Figure 2A As explained in the illustration, some REs carry reference (pilot) signals (RS) for UEs. RSs may include demodulation RSs (DM-RSs) for channel estimation at the UE (indicated as R for a particular configuration). x , where 100x is the port number, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS). RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0051] Figure 2BAn example of various DL channels within a subframe of a frame is illustrated. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including 9 RE groups (REGs), each REG including 4 consecutive REs in an OFDM symbol. The PDCCH within a BWP may be referred to as a control resource set (CORESET). Additional BWPs may be located at higher and / or lower frequencies across the channel bandwidth. The primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by the UE 104 to determine subframe / symbol timing and physical layer identity. The secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE may determine the physical cell identifier (PCI). Based on the PCI, the UE may determine the location of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth, and the system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted over the PBCH (such as the system information block (SIB)), and paging messages.

[0052] As in Figure 2C As explained in , some REs carry DM-RSs for channel estimation at the base station (indicated as R for one specific configuration, but other DM-RS configurations are possible). The UE may transmit DM-RSs for the physical uplink control channel (PUCCH) and DM-RSs for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first or first two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether a short PUCCH or a long PUCCH is transmitted and on the specific PUCCH format used. The UE may transmit a sounding reference signal (SRS). The SRS may be transmitted in the last symbol of the subframe. The SRS may have a comb structure, and the UE may transmit the SRS on one of the comb teeth. The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0053] Figure 2DAn example of various UL channels within a subframe of an illustration frame. The PUCCH may be located at a location as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) / negative acknowledgement (NACK) feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0054] Figure 3 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration of UE measurement reports; PDCP layer functionality associated with header compression / decompression, security (ciphering, cipher decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with delivery of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0055] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine coding and modulation schemes and for spatial processing. The channel estimates may be derived from reference signals and / or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0056] At the UE 350, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 350. If there are multiple spatial streams destined for the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then transforms the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the signal constellation point most likely transmitted by the base station 310. These soft decisions can be based on the channel estimates calculated by the channel estimator 358. These soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the base station 310. These data and control signals are then provided to the controller / processor 359 which implements layer 3 and layer 2 functionality.

[0057] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, cipher interpretation, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0058] Similar to the functionality described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing MAC SDUs onto TBs, demultiplexing MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0059] Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by a TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0060] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0061] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, cipher decoding, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0062] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to Figure 1 At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform operations related to Figure 1 The 198 combined aspects.

[0063] In NR and LTE, msg2 (i.e., RAR) is transmitted from the BS to the UE and is an important step for initial access (i.e., RACH procedure). However, in mmWave transmission, due to the high path loss of mmWave and the lack of narrow beams for initial access (i.e., the beams used for initial access are wider), msg2 performance becomes a bottleneck in system coverage. That is, the RACH procedure generally does not allow the use of narrow beams, which would otherwise compensate for the high path loss associated with mmW transmission, and thus the BS typically uses wide beams to transmit RAR data to the UE in the PDSCH, resulting in weaker coverage. Thus, there is a need to improve the coverage of msg2RAR PDSCH. Aspects of the present disclosure provide improvements in this coverage by allowing the base station and the UE to apply RAR PDSCH repetition, as described below with respect to Figure 4 , 5A and discussed in 5B.

[0064] Figure 4 is a call flow diagram 400 illustrating an example of a call flow between a UE and a base station applying msg2 RAR PDSCH repetition. Figure 5A is a first diagram 500 illustrating an example of msg2 RAR PDSCH repetition. Figure 5B 5 is a second diagram 520 illustrating an example of a RAR window including msg2 RARPDSCH repetitions. Figure 4, UE 402 transmits a preamble 406 for initiating a RACH procedure to BS 404. BS 404 then transmits a msg2RAR 408 in response to the received preamble 406 to UE 402. If BS 404 determines at 410 that UE 402 has not received msg2 RAR 408 (such as by determining at 410 that a message 3 (msg3) RRC connection request 409 in response to the transmitted msg2 RAR 408 has not been received from UE 402), BS 404 transmits a msg2 RAR 412 with PDSCH repetitions to UE 402. UE 402 may receive multiple RARs 412 (i.e., msg2 RARs with PDSCH repetitions) in response to the transmitted preamble 406 from BS 404. For example, referring to Figure 5A and 5B , the UE 402 may receive the multiple RARs 412 in the multiple time slots 2m+1, 2m+2 during the portion 540 of the RAR window 526. If the UE 402 correctly receives the multiple RARs 412, the UE transmits a msg3 RRC connection request 414 to the BS 404.

[0065] In one configuration, if the BS 404 determines at 416 that the UE 402 has not received the msg2 RAR 412 with PDSCH repetitions (such as by determining that no msg3 RRC connection request 414 in response to the transmitted msg2 RAR 412 with PDSCH repetitions is received from the UE 402), the BS 404 again transmits the msg2 RAR 418 with PDSCH repetitions to the UE 402. The UE 402 receives a plurality of RARs 418 (i.e., msg2 RARs with PDSCH repetitions) in response to the transmitted preamble 406 from the BS 404. For example, referring to Figure 5A and 5B , UE 402 may receive multiple RARs 418 in multiple time slots 2n+1, 2n+2 during portion 550 of RAR window 526. Assuming UE 402 correctly receives msg2 RAR 418, UE 402 transmits msg3 RRC connection request 420 to BS 404. msg2 RAR 412 may be transmitted based on a first repetition configuration, and msg2 RAR 418 may be transmitted based on a second repetition configuration. In one example, the second repetition configuration may include more repetitions than the first repetition configuration.

[0066] Reference Figure 5A and 5B, after the BS 404 receives the message 1 (msg1) preamble 406, the BS 404 may transmit a msg2 PDCCH in slot 1 of the legacy segment 530 of the RAR window 526. The msg2 PDCCH may be within the DL control information (DCI) of the CORESET that schedules the PDSCH carrying the msg2 RAR 408. Subsequently, in slot 1 of the RAR window, the BS 404 may transmit the msg2 RAR 408. If the BS 404 determines at 410 that the UE 402 did not correctly receive the msg2 RAR 408, the BS 404 may transmit one or more msg2 PDCCHs (e.g., in slot 2m and slot 2m+1 of the portion 540) to schedule multiple msg2 RARs 412. BS 404 may configure the number of msg2 RARs 412 used for transmission (i.e., the number of msg2 PDSCH repetitions during portion 540) to be two, although in other examples this number may be different. Figure 5A As illustrated in the example of , the msg2 PDCCH may also be configured to have repetitions during portion 540 (i.e., they are transmitted in more than one time slot). For example, BS 404 may transmit two msg2 PDCCHs in time slots 2m and 2m+1, respectively, wherein each msg2 PDCCH schedules one of two msg2 RARs 412 to be received in the PDSCHs of time slots 2m+1 and 2m+2, respectively. For example, the msg2 PDCCH in time slot 2m may schedule the msg2 PDSCH in time slot 2m+1, and the msg2 PDCCH in time slot 2m+1 may schedule the msg2 PDSCH in time slot 2m+2. In other examples, the msg2 PDCCH may not be configured with repetitions. For example, a single msg2 PDCCH in time slot 2m may schedule msg2 PDSCH repetitions in portion 540 (e.g., in time slots 2m+1 and 2m+2).

[0067] If BS 404 determines at 416 that UE 402 did not correctly receive msg2 RAR 412 with repetitions, BS 404 may transmit one or more additional msg2 PDCCHs (e.g., in slot 2n and slot 2n+1 of portion 550) to schedule a second plurality of msg2 RARs 418. BS 404 may configure the number of msg2 RARs 418 for transmission (i.e., the number of msg2 PDSCH repetitions during portion 550) to be four, although in other examples the number may be different. Additionally, as in Figure 5AAs illustrated in the example of , the msg2 PDCCHs may again be configured to have repetitions (i.e., they are transmitted in more than one time slot) during portion 550. For example, BS 404 may transmit four msg2 PDCCHs in time slots 2n, 2n+1, 2n+2, and 2n+3, respectively, wherein each msg2 PDCCH schedules one of four msg2 RARs 418 to be received in the PDSCHs of time slots 2n+1, 2n+2, 2n+3, and 2n+4, respectively. For example, the msg2 PDCCH in slot 2n may schedule the msg2 PDSCH in slot 2n+1, and the msg2 PDCCH in slot 2n+1 may schedule the msg2 PDSCH in slot 2n+2, the msg2 PDCCH in slot 2n+2 may schedule the msg2 PDSCH in slot 2n+3, and the msg2 PDCCH in slot 2n+3 may schedule the msg2 PDSCH in slot 2n+4. In other examples, the msg2 PDCCH may not be configured with repetitions. For example, a single msg2 PDCCH in slot 2n may schedule msg2 PDSCH repetitions in portion 550 (e.g., in slots 2n+1, 2n+2, 2n+3, and 2n+4).

[0068] The UE 402 / BS 404 may automatically apply the configured and / or predefined multi-slot repetition to the scheduled msg2 PDSCH based on the time of the scheduled PDCCH or the time of the scheduled PDSCH itself. For example, if the BS 404 transmits a msg2 PDCCH or schedules a msg2 PDSCH during the legacy segment 530, the UE and the BS may not apply any msg2 PDSCH repetition (i.e., transmit and receive only one msg2 RAR 408 as described above). In another example, if the BS 404 transmits a msg2 PDCCH or schedules a msg2 PDSCH during the portion 540, the UE and the BS may apply a two-slot msg2 PDSCH repetition (i.e., transmit and receive two msg2 RARs 412 as described above). In a further example, if the BS 404 transmits a msg2 PDCCH or schedules a msg2 PDSCH during portion 550, the UE and the BS may apply a four-slot msg2 PDSCH repetition (i.e., transmit and receive four msg2 RARs 418 as described above). In addition, the UE 402 may be configured with the msg2 RAR PDSCH repetition number prior to receiving the PDCCH, or may receive a configuration with the msg2 RAR PDSCH repetition number within the PDCCH itself.

[0069] Reference Figure 5B, the RAR window 526 may be partitioned into two or more portions with increasing slot aggregation for repetitions of the scheduled msg2 PDSCH. For example, if the base station configures the RAR window 526 to be 10 slots in a system information block (e.g., SIB1), the base station may partition the RAR window 526 such that one slot is included in the legacy segment 530 (without msg2 PDSCH repetitions), four slots are included in the portion 540 (with two-slot msg2 PDSCH repetitions), and five slots are included in the portion 550 (with four-slot msg2 PDSCH repetitions). The additional slots (i.e., additional repetitions) increase the probability that the UE will successfully receive the msg2 RAR PDSCH. For example, the legacy segment 530 may correspond to slot 1, and the first msg2 PDSCH segment (i.e., portion 540) may correspond to slots 2m, 2m+1, 2m+2, etc. The second msg2 PDSCH segment (ie, portion 550 ) may correspond to slots 2n, 2n+1, . . . , 2n+4, and may include a greater number of slots for repetition than in portion 540 .

[0070] Alternatively, one or more additional segments may be appended to the RAR window 526. For example, instead of dividing the RAR window 526 into the legacy segment 530 and the segments 540, 550 such as described above, the base station may append one or more of the segments 540 and 550 to the end of the RAR window 526 including the legacy segment 530. For example, if the base station configures the RAR window 526 to be 10 slots in SIB1, the base station may divide the RAR window 526 such that 6 slots are included in the legacy segment 530 and 4 slots are included in the segment 540, and the base station may append the additional 5 slots for the segment 550 to the end of the RAR window (e.g., effectively resulting in a 15-slot RAR window).

[0071] Regardless of whether the RAR window is divided or appended, the receiver / UE 402 can soft combine the repeated msg2 RARPDSCH to decode the data in the msg2 RAR. Repetition can also be applied based on whether the scheduled PDCCH is within the corresponding RAR window portion. For example, as described above, the UE 402 and the BS 404 can not apply msg2 PDSCH repetition during the legacy segmentation 530, apply two-slot msg2 PDSCH repetition during the portion 540 of the divided or appended RAR window, or apply four-slot msg2 PDSCH repetition during the portion 550 of the divided or appended RAR window.

[0072] During the msg2 PDSCH repetition, the same time and frequency resource allocation (i.e., symbols and RBs) and other transmission parameters (such as MCS) (according to the scheduling PDCCH) may be applied to the repeated transmission. For example, when BS 404 sends a msg2 PDCCH including a DCI, the DCI may indicate that the same number of symbols, RBs, MCS, and other transmission parameters will be used for the PDSCH in msg2 RAR 412 and msg2 RAR 418 (as well as msg2 RAR 408). Thus, the msg2 PDCCH in the legacy segment 530 may indicate transmission parameters for the msg2 PDSCH repetitions in portions 540, 550, or the msg2 PDCCH in portion 540 may indicate transmission parameters for the msg2 PDSCH repetitions in portion 550.

[0073] Alternatively, a preconfigured or predefined change in frequency resource allocation (e.g., based on preconfigured frequency hopping) may be applied to different repetitions of the msg2 PDSCH. The UE 402 may receive configurations of different frequency hopping patterns for different segments of the RAR window 526 through residual system information (RMSI) in the SIB or through DCI. For example, when the BS 404 sends SIB1 (RMSI) or a msg2 PDCCH including a DCI to the UE, the RMSI or DCI may indicate that the msg2 RAR 412 and the msg2 RAR 418 are transmitted on different frequencies or in different RBs according to the configured frequency hopping pattern indicated in the RMSI or DCI. For example, individual msg2 RARs 412 may be transmitted at different frequencies relative to each other, individual msg2 RARs 418 may be transmitted at different frequencies relative to each other, or msg2 RARs 412 may be transmitted at different frequencies relative to msg2 RARs 418. The frequency change may also be based on a configured frequency hopping pattern within an active bandwidth portion (BWP). For example, based on a predefined mapping of frequency hopping patterns to the BWP in which the RAR window 526 is received, the UE 402 and the BS 404 may receive and transmit the msg2 RAR 412 and the msg2 RAR 418, respectively, on different frequencies or RBs.

[0074] The portion of the RAR window 526 corresponding to the msg2 PDSCH repetition may also correspond to the msg2 PDCCH repetition. That is, the msg2 PDCCH repetition may be in the same or different segmented portion that includes the msg2 PDSCH repetition in the RAR window 526. In other words, the PDCCH and PDSCH may be in different segments, or may also be in the same segment, and the repetition may be applied differently based on whether the PDSCH shares a segment with the PDCCH. For example, both the msg2 PDCCH repetition and the msg2 PDSCH repetition may be within the portion 540, or they may be split into segments 540a, 540b, respectively. In such an example, segment 540a of portion 540 may include msg2 PDCCH repetitions but not msg2 PDSCH repetitions (or vice versa), segment 540b of portion 540 may include msg2 PDSCH repetitions but not msg2 PDCCH repetitions (or vice versa), and portion 550 may include both msg2 PDCCH repetitions and msg2 PDSCH repetitions (or only one of the two). Alternatively or additionally, the number of repetitions for msg2PDSCH and its scheduled PDCCH may be different. For example, in portion 550, the number of msg2 PDCCH repetitions may be two, while the number of msg2 PDSCH repetitions may be four. The difference in number between msg2 PDCCH repetitions and msg2 PDSCH repetitions may be applied similarly or differently in one or more of portions 540 or 550 and in the split portions (e.g., in one or more of segments 540a or 540b).

[0075] The addition and / or division of the additional segments of the RAR window and / or the number of PDSCH repetitions corresponding to each segment of the RAR window may be signaled by an additional bit defining the RAR window length in the system information bit field. For example, when the BS 404 configures SIB1 to include a parameter defining the RAR window length (e.g., ra-ResponseWindow or another name) in the RMSI, one or more additional bits may be added to the parameter (or a configuration including the parameter), and the BS 404 may set the one or more additional bits to indicate whether msg2 RAR repetition is applied, the parameters of the parts 540, 550 in the RAR window 526 to which msg2 RAR repetition is applied, whether the parts 540, 550 are divisions of the RAR window 526 or segments appended to the RAR window 526, and the number of msg2 RAR repetitions within each part. Alternatively, the relevant information (e.g., the above information) may be indicated in other parts of the RMSI.

[0076] Alternatively, the addition and / or division of the additional segments of the RAR window and / or the number of PDSCH repetitions corresponding to each segment of the RAR window may be signaled in one or more bits in the MIB carried by the PBCH. For example, when the BS 404 configures the MIB that schedules SIB1, one or more additional bits may be similarly added to the MIB, and the BS 404 may set the one or more additional bits to indicate whether msg2 RAR repetition is applied, the parameters of the parts 540, 550 in the RAR window 526 to which the msg2 RAR repetition is applied, whether the parts 540, 550 are divisions of the RAR window 526 or segments appended to the RAR window 526, and the number of msg2 RAR repetitions within each part.

[0077] In addition, the mapping between the bit field used to indicate the parameters of the RAR window in the system information and the segmentation of the RAR window and / or their corresponding time length and / or their associated PDSCH repetition number can be predefined, for example, by a fixed table and / or by one of a plurality of mappings depending on a bit field in the MIB. For example, when the BS 404 configures the MIB for scheduling SIB1, the BS 404 may indicate the system information based on one or more predefined mappings between the system information and the value or index of the bit field in the MIB. For example, the BS 404 may set one or more bits in the MIB to one or more predefined indexes, which indicate whether msg2 RAR repetition is applied, the parameters of the parts 540, 550 in the RAR window 526 to which the msg2 RAR repetition is applied, whether the parts 540, 550 are divisions of the RAR window 526 or segments appended to the RAR window 526, and the number of msg2 RAR repetitions in each part.

[0078] In the case of dual connectivity, the addition and / or partitioning of the additional segments of the RAR window and / or the number of PDSCH repetitions corresponding to each segment of the RAR window can be configured by the RRC of the other link. For example, in E-UTRA-NR dual connectivity (EN-DC), BS 404 can be a gNB operating in NR, and UE 402 can be connected to BS 404 and another BS that can be an eNB operating in LTE. Alternatively, BS 404 may include two separate nodes (eNB and gNB). In either case, the eNB can send RRC messages and other control information to the UE, while the gNB sends data to the UE. Accordingly, in such an example, the eNB can configure the MIB scheduling SIB1 and indicate system information to the UE (e.g., in RMSI, in the MIB, or based on a predefined mapping), after which the gNB transmits msg2 RAR to the UE as described above. In other examples besides EN-DC (where the dual connectivity is not inter-RAT), one node or BS may configure the system information for msg2 RAR, while the other node or BS may transmit msg2 RAR and repetitions.

[0079] In one example, as discussed above, repetition of the msg2 PDSCH may be done only in the later segments (e.g., portions 540 and 550, instead of the legacy segment 530) of the RAR window 526, and only for UEs that have not received a msg3 response (this avoids wasting resources caused by unnecessary PDSCH repetitions for all UEs). In other examples, repetition of the msg2 PDSCH may be configured for UEs in the later segments (e.g., portions 540 and 550), regardless of whether a msg3 response is successfully received (e.g., based on the time when the msg2 PDCCH is transmitted or the msg2 PDSCH is scheduled, as described above).

[0080] Figure 6 600 is a flow chart of a wireless communication method. The method may be performed by a device at a UE 402 (e.g., UE 104, 350, 402; device 802). The device may be a processor / modem used with the UE 402 or the UE 402 itself. The device is referred to herein as a UE. Optional aspects are illustrated in dashed lines. The method allows a UE to improve data reception in a msg2 RAR in a mmW environment through msg2 RARPDSCH repetition.

[0081] At 602, the UE transmits a preamble to the base station for initiating a RACH procedure. For example, 602 can be performed by the preamble component 840. For example, referring to Figure 4 , UE 402 transmits msg1 preamble 406 to BS 404 to initiate a RACH procedure.

[0082] At 606, the UE receives a plurality of RARs from the base station in response to the transmitted preamble. For example, 606 may be performed by the RAR component 842. The plurality of RARs are received in a plurality of time slots during a portion of the RAR window. For example, referring to Figure 4 , 5A 5B, UE 402 receives multiple RARs 412 in response to the transmitted preamble 406 from BS 404 in time slots 2m+1, 2m+2 of portion 540. The multiple RARs 412 are received in multiple time slots 2m+1, 2m+2 during portion 504 of RAR window 526.

[0083] In one configuration, at 604, the UE may determine that a first RAR in response to the preamble was not successfully received. For example, 604 may be performed by the determining component 844. In such a configuration, at 606, a plurality of RARs are received based on the first RAR not being successfully received. For example, referring to Figure 4 , the UE may determine that the first RAR 408 in response to the preamble 406 was not successfully received based on not receiving the msg3 RRC connection request 409 from the UE 402. In such a configuration, multiple RARs 412 are received at 606 based on the first RAR 408 not being successfully received.

[0084] In one configuration, at 608, the UE combines (e.g., by soft combining) the received RARs into one RAR, and at 610, attempts to decode the one RAR. For example, 608 may be performed by the combining component 846, and 610 may be performed by the decoding component 848. If, at 610, the UE successfully decodes the one RAR, then at 612, the UE transmits an RRC connection request in response to the one RAR to the base station. For example, 612 may be performed by the RRC connection request component 850. However, if, at 610, the UE does not successfully decode the plurality of RARs, then returning to 606, the UE receives a second plurality of RARs from the base station in a second plurality of time slots. The second plurality of RARs are received based on the plurality of RARs not being successfully received. For example, referring to Figure 4 , 5A, 5B, UE 402 combines the RARs 412 received from the PDSCH in time slots 2m+1, 2m+2 into one RAR, and attempts to decode the one RAR at 610. If UE 402 successfully decodes the one RAR at 610, UE 402 transmits an RRC connection request 414 in response to the one RAR to BS 404 at 612. However, if UE 402 does not successfully decode the multiple RARs 412 from the PDSCH in time slots 2m+1, 2m+2 at 610, then returning to 606, UE 402 receives a second plurality of RARs 418 from BS 404 in a second plurality of time slots 2n+1, 2n+2, 2n+3, 2n+4. The second plurality of RARs 418 are received based on the fact that the multiple RARs 412 are not successfully received.

[0085] In one configuration, the second plurality of time slots may include a greater number of time slots than the plurality of time slots. Figure 5A , 5B , the second plurality of time slots 2n+1, 2n+2, 2n+3, 2n+4 in portion 550 includes four time slots, while the plurality of time slots 2m+1, 2m+2 in portion 540 includes two time slots.

[0086] In one configuration, each RAR in the plurality of RARs may be received with the same MCS in the same set of subcarriers and the same set of symbols in a corresponding time slot in the plurality of time slots. Figure 5A , the RARs received in slots 2m+1 and 2m+2 may have the same MCS and may occupy the same set of subcarriers and symbols in each slot. Similarly, the RARs received in slots 2n+1, 2n+2, 2n+3, and 2n+4 may have the same MCS and may occupy the same set of subcarriers and symbols in each slot.

[0087] However, in another configuration, each of the multiple RARs may be received with the same MCS in the same set of symbols and different sets of subcarriers based on the frequency hopping pattern for the multiple RARs. That is, the RAR received in slot 2m+2 may be in a different frequency range (based on the preconfigured frequency hopping pattern) than the RAR received in slot 2m+1. The same may be true for the RARs received in slots 2n+1, 2n+2, 2n+3, and 2n+4.

[0088] In one configuration, the UE may receive at least one PDCCH that schedules a PDSCH for receiving the plurality of RARs. Figure 4 , 5A, UE 402 receives two PDCCHs (in slots 2m, 2m+1) that schedule PDSCHs for receiving multiple RARs 412. In this example, msg2 PDCCH repetition is configured. If msg2 PDCCH repetition is not configured, UE 402 may receive only the PDCCH that schedules PDSCHs for receiving multiple RARs 412 in slot 2m+1.

[0089] In one configuration, at least one PDCCH that schedules a PDSCH for receiving the plurality of RARs includes a plurality of PDCCHs, each PDCCH including the same information for scheduling a PDSCH for receiving the plurality of RARs. Figure 4 , 5A , at least one PDCCH for scheduling PDSCHs for receiving multiple RARs 412 includes multiple PDCCHs in time slots 2m, 2m+1, and each PDCCH includes the same information for scheduling PDSCHs for receiving multiple RARs 412.

[0090] In one configuration, at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window. Figure 4 , 5A , 5B, portion 540 of the RAR window 526 may be split into two segments 540a, 540b, and at least one PDCCH may be received during a first configured segment 540a within portion 540 of the RAR window 526, and multiple RARs 412 may be received during a second configured segment 540b within portion 540 of the RAR window 526 after the first configured segment 540a within portion 540 of the RAR window 526.

[0091] In one configuration, at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during the first configured segment of the RAR window. Figure 4 , 5A 5B, portion 540 of the RAR window 526 may not be subdivided into segments, at least one PDCCH may be received during a first configured segment (portion 540) of the RAR window 526, and multiple RARs 412 may be received during the first configured segment (portion 540) of the RAR window 526.

[0092] In one configuration, the UE receives a configuration indicating a frequency hopping pattern for receiving multiple RARs. The configuration may be received via one of DCI or system information. In such a configuration, multiple RARs are received based on the received configuration. For example, referring to Figure 4 , 5A , UE 402 may receive a configuration indicating a frequency hopping pattern for receiving multiple RARs 412 in PDSCH of time slots 2m+1, 2m+2. The configuration may be received via one of DCI or system information (e.g., SIB1 or RMSI). In such a configuration, UE 402 receives multiple RARs 412 based on the received configuration.

[0093] In one configuration, the UE may receive a configuration indicating whether RAR repetition is configured. The configuration may be received via one of the MIB or system information. In such a configuration, multiple RARs are received based on the received configuration. For example, referring to Figure 4 , 5A , UE 402 may receive a configuration indicating whether RAR repetition is configured after legacy segment 530. The configuration may be received via one of MIB or system information (e.g., SIB1 or RMSI). In such a configuration, assuming RAR repetition is configured, multiple RARs 412 are received based on the received configuration.

[0094] In one configuration, the UE may receive a configuration indicating at least one of: a partition of the RAR window for RAR repetition, a segment within the RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segment. The configuration may be received via one of a MIB, a system information, or an RRC message. In such a configuration, multiple RARs are received based on the received configuration. For example, referring to Figure 5A , 5B , the UE 402 may receive a configuration indicating at least one of: a partition of the RAR window 526 for RAR repetition (e.g., portion 540 or 550), one or more segments within the RAR window 526 for RAR repetition (e.g., segments 540a, 540b), or a number of RAR repetitions for each RAR window partition or segment (e.g., two for portion 540 and four for portion 550 as illustrated). The configuration may be received via one of a MIB, system information (SIB1 or RMSI), or an RRC message. In such a configuration, a plurality of RARs 412 are received based on the received configuration.

[0095] Figure 7700 is a flow chart of a wireless communication method. The method may be performed by a device at BS 404 (e.g., base station 102 / 180, 310, 404; device 902). The device may be a processor / modem used in conjunction with BS 404 or BS 404 itself. The device is referred to herein as BS. Optional aspects are illustrated in dashed lines. The method allows the BS to improve data transmission in msg2 RAR in mmW environments through msg2 RAR PDSCH repetition.

[0096] At 702, the BS receives a preamble from the UE for initiating a RACH procedure. For example, 702 can be performed by the preamble component 940. For example, referring to Figure 4 , BS 404 receives a preamble 406 from UE 402 for initiating a RACH procedure.

[0097] At 704, the BS transmits a first RAR to the UE in response to receiving the preamble. For example, 704 may be performed by the RAR component 942. The first RAR is transmitted during the first portion of the RAR window. For example, referring to Figure 4 , 5A 5B, BS 404 transmits a first RAR 408 to UE 402 in response to receiving preamble 406. First RAR 408 is transmitted during a first portion of RAR window 526 (eg, legacy segment 530).

[0098] At 706, the BS determines that an RRC connection request in response to the transmitted first RAR is not received. For example, 706 can be performed by the determining component 944. For example, referring to Figure 4 , the BS 404 determines at 410 that the RRC connection request 409 in response to the transmitted first RAR 408 is not received. When the BS 404 fails to decode the RRC connection request 409 from the UE 402, the BS 404 may determine at 410 that the RRC connection request 409 in response to the transmitted first RAR 408 is not received.

[0099] At 708, upon determining that an RRC connection request in response to the transmitted first RAR is not received, the BS transmits a first plurality of RARs to the UE in a first plurality of time slots during a second portion of the RAR window after the first portion of the RAR window. For example, 708 may also be performed by the RAR component 942. For example, referring to Figure 4 , 5A, 5B, when 410 determines that an RRC connection request 409 is not received in response to the transmitted first RAR 408, the BS 404 transmits a first plurality of RARs 412 to the UE 402 in a first plurality of time slots 2m+1, 2m+2 during a second portion (e.g., portion 540) of the RAR window 526 after the first portion (e.g., legacy segment 530) of the RAR window 526.

[0100] In one configuration, the BS receives an RRC connection request from the UE in response to the transmitted first plurality of RARs. Figure 4 , BS 404 may receive an RRC connection request 414 in response to the transmitted first plurality of RARs 412 from UE 402.

[0101] In one configuration, the BS determines that a second RRC connection request in response to the transmitted first plurality of RARs is not received. Furthermore, upon determining that a second RRC connection request in response to the transmitted first plurality of RARs is not received, the BS transmits a second plurality of RARs to the UE in a second plurality of time slots during a third portion of the RAR window after the second portion of the RAR window. For example, referring to Figure 4 , 5A , 5B, the BS 404 determines at 416 that an RRC connection request 414 in response to the transmitted first plurality of RARs 412 is not received. In addition, upon determining that an RRC connection request 414 in response to the transmitted first plurality of RARs 412 is not received, the BS 404 transmits a second plurality of RARs 418 to the UE 402 in a second plurality of time slots 2n+1, 2n+2, 2n+3, 2n+4 during a third portion (e.g., portion 550) of the RAR window 526 after the second portion (e.g., portion 540) of the RAR window 526.

[0102] In one configuration, the second plurality of time slots includes a greater number of time slots than the first plurality of time slots. Figure 5A The second plurality of time slots 2n+1, 2n+2, 2n+3, 2n+4 includes a greater number of time slots than the first plurality of time slots 2m+1, 2m+2. In one configuration, the BS 404 receives an RRC connection request 420 from the UE 402 in response to the transmitted second plurality of RARs 418.

[0103] In one configuration, each RAR in the first plurality of RARs transmits with the same MCS in a corresponding time slot in the first plurality of time slots in a same set of subcarriers and a same set of symbols. Figure 4 , 5A, each RAR in the first plurality of RARs 412 may be transmitted with the same MCS in the same set of subcarriers and the same set of symbols in a corresponding slot in the first plurality of slots 2m+1, 2m+2. Similarly, the RARs in the second plurality of slots 2n+1, 2n+2, 2n+3, 2n+4 may be transmitted with the same MCS in the same set of subcarriers and symbols in the slot.

[0104] In one configuration, each RAR in the first plurality of RARs transmits with the same MCS in the same set of symbols and different sets of subcarriers based on a frequency hopping pattern for the first plurality of RARs. Figure 4 , 5A , each RAR in the first plurality of RARs 412 may be transmitted with the same MCS in the same set of symbols and a different set of subcarriers based on the frequency hopping pattern for the first plurality of RARs 412. Similarly, each RAR in the second plurality of RARs 418 may be transmitted with the same MCS, the same symbols, but with different subcarriers defined by the preconfigured frequency hopping pattern.

[0105] In one configuration, the BS transmits at least one PDCCH that schedules a PDSCH for transmission of the first plurality of RARs. Figure 4 , 5A , BS 404 transmits at least one PDCCH in time slots 2m, 2m+1, the at least one PDCCH scheduling a PDSCH for transmission of the first plurality of RARs 412 in time slots 2m+1, 2m+2. In one configuration, the at least one PDCCH scheduling a PDSCH for transmission of the first plurality of RARs includes a plurality of PDCCHs, each PDCCH including the same information for scheduling a PDSCH for transmission of the first plurality of RARs. For example, referring to Figure 4 , 5A , the at least one PDCCH scheduling the PDSCH for transmission of the first plurality of RARs 412 includes a plurality of PDCCHs (in Figure 5A In one configuration, at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs is transmitted during a second configured segment of the RAR window following the first configured segment of the RAR window. For example, referring to Figure 4 , 5A, 5B, at least one PDCCH is transmitted during a first configured segment (e.g., segment 540a) of the RAR window 526, and a first plurality of RARs 412 are transmitted during a second configured segment (e.g., segment 540b) of the RAR window 526 following the first configured segment (e.g., segment 540a) of the RAR window 526 (here, portion 540 is split into separate segments 540a, 540b for msg2 PDCCH (with or without repetition) and msg2 PDSCH repetition, respectively). In one configuration, at least one PDCCH is transmitted during the first configured segment of the RAR window, and a first plurality of RARs are transmitted during the first configured segment of the RAR window. For example, referring to Figure 4 , 5A , at least one PDCCH is transmitted during a first configured segment (e.g., portion 540) of the RAR window 526, and a first plurality of RARs 412 are transmitted during the first configured segment (e.g., portion 540) of the RAR window 526 (here, portion 540 is not split into separate segments 540a, 540b for msg2 PDCCH (with or without repetition) and msg2 PDSCH repetition, respectively).

[0106] In one configuration, the BS transmits a configuration indicating a frequency hopping pattern for transmission of a first plurality of RARs. The configuration is transmitted via one of a DCI or system information. The first plurality of RARs are transmitted based on the transmitted configuration. For example, referring to Figure 4 , BS 404 transmits a configuration indicating a frequency hopping pattern for transmission of the first plurality of RARs 412. The configuration is transmitted through one of DCI or system information (eg, SIB1 or RMSI). The first plurality of RARs 412 are transmitted based on the transmitted configuration.

[0107] In one configuration, the BS transmits a configuration indicating whether RAR repetition is configured. The configuration is transmitted via one of the MIB or system information. The first plurality of RARs are transmitted based on the transmitted configuration. For example, referring to Figure 4 , BS 404 transmits a configuration indicating whether RAR repetition is configured. The configuration is transmitted through one of MIB or system information (eg, SIB1 or RMSI). The first plurality of RARs 412 is transmitted based on the transmitted configuration.

[0108] In one configuration, the BS transmits a configuration indicating at least one of: a partition of the RAR window for RAR repetition, a segment within the RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segment. The configuration is transmitted via one of a MIB, a system information, or an RRC message. The first plurality of RARs is transmitted based on the transmitted configuration. For example, referring to Figure 4 , 5A , 5B, BS 404 transmits a configuration indicating at least one of: a partition of RAR window 526 for RAR repetition (e.g., portion 540 or 550), one or more segments within RAR window 526 for RAR repetition (e.g., segments 540a, 540b), or a number of RAR repetitions for each RAR window partition or segment, respectively (e.g., two-slot or four-slot repetitions). The configuration is transmitted through one of the MIB, system information (SIB1 or RMSI), or an RRC message. The first plurality of RARs 412 (and the second plurality of RARs 418) are transmitted based on the transmitted configuration.

[0109] Figure 8800 is an example of a hardware implementation of an illustrative device 802. The device 802 is a UE and includes a cellular baseband processor 804 (also referred to as a modem) coupled to a cellular RF transceiver 822 and one or more subscriber identity modules (SIM) cards 820, an application processor 806 coupled to a secure digital (SD) card 808 and a screen 810, a Bluetooth module 812, a wireless local area network (WLAN) module 814, a global positioning system (GPS) module 816, and a power supply 818. The cellular baseband processor 804 communicates with the UE 104 and / or the BS 102 / 180 through the cellular RF transceiver 822. The cellular baseband processor 804 may include a computer-readable medium / memory. The computer-readable medium / memory may be non-transient. The cellular baseband processor 804 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the cellular baseband processor 804, causes the cellular baseband processor 804 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 804 when executing software. The cellular baseband processor 804 further includes a receiving component 830, a communication manager 832, and a transmission component 834. The communication manager 832 includes one or more of the illustrated components. The components within the communication manager 832 may be stored in a computer-readable medium / memory and / or configured as hardware within the cellular baseband processor 804. The cellular baseband processor 804 may be a component of the UE 350 and may include a memory 360 and / or at least one of the following: a TX processor 368, an RX processor 356, and a controller / processor 359. In one configuration, the device 802 may be a modem chip and include only the baseband processor 804, while in another configuration, the device 802 may be the entire UE (e.g., see Figure 3 350) and includes the aforementioned additional modules of device 802.

[0110] The communication manager 832 includes a preamble component 840 configured to transmit a preamble for initiating a RACH procedure to a base station, e.g., as described in conjunction with 602. The communication manager 832 also includes a RAR component 842 configured to receive a plurality of RARs from the base station in response to the transmitted preamble, the plurality of RARs being received in a plurality of time slots during a portion of the RAR window, e.g., as described in conjunction with 606.

[0111] In one configuration, the communication manager 832 also includes a determining component 844 configured to determine that a first RAR in response to the preamble was not successfully received, wherein the plurality of RARs are received based on the first RAR not being successfully received, e.g., as described in conjunction with 604.

[0112] In one configuration, the communication manager 832 further includes a combining component 846 that receives input in the form of received RARs from the RAR component 842 and is configured to combine the received RARs into one RAR, e.g., as described in conjunction with 608. The communication manager 832 further includes a decoding component 848 that receives input in the form of the one RAR from the combining component 846 and is configured to decode the one RAR, e.g., as described in conjunction with 610. The communication manager 832 further includes an RRC connection request component 850 that receives input in the form of the one RAR from the combining component 846 and the decoding component 848 and is configured to transmit an RRC connection request in response to the one RAR to the base station, e.g., as described in conjunction with 612.

[0113] In one configuration, the decoding component 848 is configured to unsuccessfully decode the plurality of RARs, and the RAR component 842 is further configured to receive a second plurality of RARs from the base station in a second plurality of time slots, the second plurality of RARs being received based on the plurality of RARs being unsuccessfully received, wherein the second plurality of time slots includes a greater number of time slots than the plurality of time slots.

[0114] In one configuration, the RAR component 842 is further configured to receive at least one PDCCH that schedules a PDSCH for receiving the multiple RARs. In one configuration, the RAR component 842 is further configured to receive a configuration indicating a frequency hopping pattern for receiving the multiple RARs, the configuration being received through one of a DCI or system information, and the multiple RARs are received based on the received configuration. In one configuration, the RAR component 842 is further configured to receive a configuration indicating whether RAR repetition is configured, the configuration being received through one of a MIB or system information, wherein the multiple RARs are received based on the received configuration. In one configuration, the RAR component 842 is further configured to receive a configuration indicating at least one of the following: a partition of the RAR window for RAR repetition, a segmentation within the RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segmentation, the configuration being received through one of a MIB, system information, or an RRC message, wherein the multiple RARs are received based on the received configuration.

[0115] The apparatus may include executing Figure 4 and 6 The additional components of each box of the algorithm in the preceding flowchart. Thus, Figure 4 and 6Each block in the aforementioned flow chart of can be performed by a component and the device may include one or more of those components. These components can be one or more hardware components specially configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0116] In one configuration, the device 802 and in particular the cellular baseband processor 804 includes means for transmitting a preamble for initiating a RACH procedure to a base station; and means for receiving from the base station a plurality of RARs in response to the transmitted preamble, the plurality of RARs being received in a plurality of time slots during a portion of a RAR window. In one configuration, the device 802 and in particular the cellular baseband processor 804 may include means for determining that a first RAR in response to the preamble was not successfully received, wherein the plurality of RARs are received based on the first RAR not being successfully received. In one configuration, the device 802 and in particular the cellular baseband processor 804 may include means for combining the received RARs into one RAR and means for decoding the one RAR, wherein the means for transmitting is further configured to transmit to the base station a radio resource control (RRC) connection request in response to the one RAR. In one configuration, the device 802 and in particular the cellular baseband processor 804 may include means for unsuccessfully decoding a plurality of RARs, and the means for receiving may be further configured to receive a second plurality of RARs from the base station in a second plurality of time slots, the second plurality of RARs being received based on the plurality of RARs being unsuccessfully received, wherein the second plurality of time slots includes a greater number of time slots than the plurality of time slots. In one configuration, the means for receiving is further configured to receive at least one PDCCH scheduling a PDSCH for receiving the plurality of RARs.

[0117] The aforementioned means may be one or more of the aforementioned components in the device 802 configured to perform the functions recited by the aforementioned means. As described above, the device 802 may include the TX processor 368, the RX processor 356, and the controller / processor 359. Thus, in one configuration, the aforementioned means may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the aforementioned means.

[0118] Fig. 9900 is an example of a hardware implementation of an illustrated device 902. The device 902 is a BS and includes a baseband unit 904. The baseband unit 904 can communicate with the UE 104 via a cellular RF transceiver. The baseband unit 904 may include a computer-readable medium / memory. The baseband unit 904 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory. The software, when executed by the baseband unit 904, enables the baseband unit 904 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the baseband unit 904 when executing the software. The baseband unit 904 further includes a receiving component 930, a communication manager 932, and a transmission component 934. The communication manager 932 includes one or more of the illustrated components. The components within the communication manager 932 may be stored in a computer-readable medium / memory and / or configured as hardware within the baseband unit 904. The baseband unit 904 may be a component of the BS 310 and may include the memory 376 and / or at least one of: the TX processor 316 , the RX processor 370 , and the controller / processor 375 .

[0119] The communication manager 932 includes a preamble component 940 configured to receive a preamble from the UE for initiating a RACH procedure, e.g., as described in conjunction with 702. The communication manager 932 also includes a RAR component 942 that receives input in the form of the preamble from the preamble component 940 and is configured to transmit a first RAR to the UE in response to receiving the preamble, the first RAR being transmitted during a portion of the RAR window, e.g., as described in conjunction with 704. The communication manager 932 also includes a determination component 944 configured to determine that an RRC connection request in response to the transmitted first RAR is not received, e.g., as described in conjunction with 706. The RAR component 942 receives input in the form of the determination from the determination component 944 and is also configured to, upon determining that an RRC connection request is not received in response to the transmitted first RAR, transmit a first plurality of RARs to the UE in a first plurality of time slots during a second portion of the RAR window following the first portion of the RAR window, e.g., as described in conjunction with 708.

[0120] In one configuration, the determining component 944 is further configured to determine that a second RRC connection request in response to the transmitted first plurality of RARs is not received, and the RAR component 942 is further configured to transmit a second plurality of RARs to the UE in a second plurality of time slots during a third portion of the RAR window after the second portion of the RAR window upon determining that a second RRC connection request in response to the transmitted first plurality of RARs is not received, wherein the second plurality of time slots includes a greater number of time slots than the first plurality of time slots.

[0121] In one configuration, the RAR component 942 is further configured to transmit at least one PDCCH of a PDSCH for transmission of a first plurality of RARs. In one configuration, the RAR component 942 is further configured to transmit a configuration indicating a frequency hopping pattern for transmission of the first plurality of RARs, the configuration being transmitted through one of a DCI or system information, the first plurality of RARs being transmitted based on the transmitted configuration. In one configuration, the RAR component 942 is further configured to transmit a configuration indicating whether RAR repetition is configured, the configuration being transmitted through one of a MIB or system information, wherein the first plurality of RARs are transmitted based on the transmitted configuration. In one configuration, the RAR component 942 is further configured to transmit a configuration indicating at least one of the following: a partition of a RAR window for RAR repetition, a segmentation within a RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segmentation, the configuration being transmitted through one of a MIB, system information, or an RRC message, wherein the first plurality of RARs are transmitted based on the transmitted configuration.

[0122] The apparatus may include executing Figure 4 and 7 The additional components of each box of the algorithm in the preceding flowchart. Thus, Figure 4 and 7 Each block in the aforementioned flow chart of can be performed by a component and the device may include one or more of those components. These components can be one or more hardware components specially configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0123] In one configuration, the device 902, and in particular the baseband unit 904, includes means for receiving a preamble from a UE for initiating a RACH procedure; and means for transmitting a first RAR to the UE in response to receiving the preamble, the first RAR being transmitted during a first portion of the RAR window. The device 902, and in particular the baseband unit 904, also includes means for determining that an RRC connection request in response to the transmitted first RAR is not received; and the means for transmitting is further configured to transmit the first plurality of RARs to the UE in a first plurality of time slots during a second portion of the RAR window following the first portion of the RAR window upon determining that an RRC connection request in response to the transmitted first RAR is not received. In one configuration, the means for determining is further configured to determine that a second RRC connection request in response to the transmitted first plurality of RARs is not received; and the means for transmitting is further configured to transmit the second plurality of RARs to the UE in a second plurality of time slots during a third portion of the RAR window after the second portion of the RAR window upon determining that the second RRC connection request in response to the transmitted first plurality of RARs is not received, wherein the second plurality of time slots includes a greater number of time slots than the first plurality of time slots. In one configuration, the means for transmitting is further configured to transmit at least one PDCCH of the PDSCH that schedules transmission of the first plurality of RARs.

[0124] The aforementioned means may be one or more of the aforementioned components in the device 902 configured to perform the functions recited by the aforementioned means. As described above, the device 902 may include the TX processor 316, the RX processor 370, and the controller / processor 375. Thus, in one configuration, the aforementioned means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the aforementioned means.

[0125] Refer again Figure 4 , 5A , 5B, as discussed above, UE 402 may not be able to receive msg2 RAR 408 due to high path loss and the relatively wide beam (rather than a narrow beam) carrying msg2 RAR 408. To improve reception of msg2 RAR, then within portion 540 of RAR window 526, BS 404 may transmit msg2 RAR with PDSCH repetitions, such as multiple RARs 412 in multiple time slots (e.g., time slots 2m+1, 2m+2). msg2 PDSCH may be scheduled by one or more msg2 PDCCHs. If more than one msg2 PDCCH is used (such as Figure 5A), the msg2 PDCCH is also configured with repetitions. If the UE 402 cannot correctly receive the plurality of RARs 412, then within the portion 550 of the RAR window 526, the BS 404 may transmit a msg2 RAR with more PDSCH repetitions, such as a second plurality of RARs 418 within a second plurality of time slots (e.g., time slots 2n+1, 2n+2, 2n+3, 2n+4). The transmission / reception of the msg2 RAR PDSCH with repetitions improves the performance of the RACH procedure.

[0126] It should be understood that the specific order or hierarchy of each box in the disclosed process / flowchart is an illustration of an example approach. It should be understood that the specific order or hierarchy of each box in these process / flowcharts can be rearranged based on design preferences. In addition, some boxes can be combined or omitted. The attached method claims present the elements of various boxes in an exemplary order and are not meant to be limited to the specific order or hierarchy presented.

[0127] 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 in this article can be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown in this article, but should be granted the full scope consistent with the claims in language, wherein the singular reference of the elements is not intended to represent "there is and only one", but "one or more", unless otherwise stated. Terms such as "if", "when..." and "when..." should be interpreted as meaning "under the condition", rather than implying a direct time relationship or reaction. That is, these phrases (e.g., "when...") do not imply an immediate action in response to the occurrence of an action or during the occurrence of an action, but only imply that an action will occur when the condition is met, and no specific or immediate time constraints are required for the action to occur. The wording "exemplary" is used in this article to represent "used as an example, instance, or explanation". Any aspect described as "exemplary" herein need not be interpreted as being superior to or superior to other aspects. Unless otherwise stated, the term "some / certain" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" include any combination of A, B, and / or C, and may include multiple A, multiple B, or multiple C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be only A, only B, only C, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout the present disclosure that are currently or later known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, regardless of whether such disclosure is expressly recited in the claims. The terms “module,” “mechanism,” “element,” “device,” etc. may not be substitutes for the term “means.” Thus, no claim element should be construed as means-plus-function unless the element is explicitly recited using the phrase “means for….”

[0128] The following examples are merely illustrative and may be combined with other embodiments or aspects of the teachings described herein without limitation.

[0129] Example 1 is a wireless communication method for a device at a user equipment (UE), comprising: transmitting a preamble code for initiating a random access channel (RACH) procedure to a base station; and receiving a plurality of random access responses (RARs) in response to the transmitted preamble code from the base station, the plurality of RARs being received in a plurality of time slots during a portion of a RAR window.

[0130] Example 2 is the method of Example 1, further comprising determining that a first RAR in response to the preamble is not successfully received, wherein the plurality of RARs are received based on the first RAR not being successfully received.

[0131] Example 3 is the method of Example 1 or 2, further comprising: combining the received RARs into one RAR; decoding the one RAR; and transmitting a radio resource control (RRC) connection request in response to the one RAR to a base station.

[0132] Example 4 is the method of Example 1 or 2, further comprising: unsuccessfully decoding the multiple RARs; and receiving a second multiple RARs from the base station in a second multiple time slots, the second multiple RARs being received based on the multiple RARs not being successfully received, wherein the second multiple time slots include a greater number of time slots than the multiple time slots.

[0133] Example 5 is the method of any one of Examples 1 to 4, further comprising receiving at least one physical downlink control channel (PDCCH) scheduling a physical downlink shared channel (PDSCH) for receiving the plurality of RARs.

[0134] Example 6 is the method of Example 5, wherein the at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during a second configured segment of the RAR window after the first configured segment of the RAR window.

[0135] Example 7 is the method of Example 5, wherein the at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during the first configured segment of the RAR window.

[0136] Example 8 is the method of any one of Examples 1 to 7, further comprising receiving a configuration indicating a frequency hopping pattern for receiving the multiple RARs, the configuration being received via one of downlink control information (DCI) or system information, the multiple RARs being received based on the received configuration.

[0137] Example 9 is the method of any one of Examples 1 to 8, further comprising receiving a configuration indicating whether RAR repetition is configured, the configuration being received via one of a master information block (MIB) or system information, wherein the plurality of RARs are received based on the received configuration.

[0138] Example 10 is the method of any one of Examples 1 to 9, further comprising receiving a configuration indicating at least one of: a partition of the RAR window for RAR repetition, a segmentation within the RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segmentation, the configuration being received via one of a master information block (MIB), system information, or a radio resource control (RRC) message, wherein the plurality of RARs are received based on the received configuration.

[0139] Example 11 is an apparatus for wireless communication, which is a device at a user equipment (UE), comprising: a memory; and at least one processor coupled to the memory, which is configured to: transmit a preamble code for initiating a random access channel (RACH) procedure to a base station; and receive multiple random access responses (RARs) in response to the transmitted preamble code from the base station, the multiple RARs being received in multiple time slots during a portion of the RAR window.

[0140] Example 12 is the apparatus of Example 11, wherein the at least one processor is further configured to determine that a first RAR in response to the preamble is not successfully received, wherein the plurality of RARs are received based on the first RAR not being successfully received.

[0141] Example 13 is the apparatus of Example 11 or 12, wherein the at least one processor is further configured to: combine the received RARs into one RAR; decode the one RAR; and transmit a radio resource control (RRC) connection request in response to the one RAR to the base station.

[0142] Example 14 is the apparatus of Example 11 or 12, wherein the at least one processor is further configured to: unsuccessfully decode the plurality of RARs; and receive a second plurality of RARs from the base station in a second plurality of time slots, the second plurality of RARs being received based on the plurality of RARs not being successfully received, wherein the second plurality of time slots includes a greater number of time slots than the plurality of time slots.

[0143] Example 15 is the apparatus of any one of Examples 11 to 14, wherein the at least one processor is further configured to receive at least one physical downlink control channel (PDCCH) scheduling a physical downlink shared channel (PDSCH) for receiving the multiple RARs.

[0144] Example 16 is the apparatus of Example 15, wherein the at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window.

[0145] Example 17 is the apparatus of Example 15, wherein the at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during the first configured segment of the RAR window.

[0146] Example 18 is a wireless communication method for a device at a base station (BS), comprising: receiving a preamble for initiating a random access channel (RACH) procedure from a user equipment (UE); transmitting a first random access response (RAR) to the UE in response to receiving the preamble, the first RAR being transmitted during a first part of a RAR window; determining that a radio resource control (RRC) connection request is not received in response to the transmitted first RAR; and upon determining that the RRC connection request is not received in response to the transmitted first RAR, transmitting a first plurality of RARs to the UE in a first plurality of time slots during a second part of the RAR window after the first part of the RAR window.

[0147] Example 19 is the method of Example 18, further comprising: determining that a second RRC connection request in response to the transmitted first plurality of RARs is not received; and upon determining that the second RRC connection request in response to the transmitted first plurality of RARs is not received, transmitting a second plurality of RARs to the UE in a second plurality of time slots during a third portion of the RAR window after the second portion of the RAR window, wherein the second plurality of time slots includes a greater number of time slots than the first plurality of time slots.

[0148] Example 20 is the method of Example 18 or 19, further comprising transmitting at least one physical downlink control channel (PDCCH) of a physical downlink shared channel (PDSCH) scheduling transmission for the first plurality of RARs.

[0149] Example 21 is the method of Example 20, wherein the at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during a second configured segment of the RAR window after the first configured segment of the RAR window.

[0150] Example 22 is the method of Example 20, wherein the at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during the first configured segment of the RAR window.

[0151] Example 23 is a method of any one of Examples 18 to 22, further comprising transmitting a configuration indicating a frequency hopping pattern for transmission of a first plurality of RARs, the configuration being transmitted via one of downlink control information (DCI) or system information, the first plurality of RARs being transmitted based on the transmitted configuration.

[0152] Example 24 is the method of any one of Examples 18 to 23, further comprising transmitting a configuration indicating whether RAR repetition is configured, the configuration being transmitted via one of a master information block (MIB) or system information, wherein the first plurality of RARs is transmitted based on the transmitted configuration.

[0153] Example 25 is the method of any one of Examples 18 to 24, further comprising transmitting a configuration indicating at least one of: a partition of the RAR window for RAR repetition, a segmentation within the RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segmentation, the configuration being transmitted via one of a master information block (MIB), system information, or an RRC message, wherein the first plurality of RARs is transmitted based on the transmitted configuration.

[0154] Example 26 is an apparatus for wireless communication, which is a device at a base station (BS), comprising: a memory; and at least one processor coupled to the memory, which is configured to: receive a preamble for initiating a random access channel (RACH) procedure from a user equipment (UE); transmit a first random access response (RAR) to the UE in response to receiving the preamble, the first RAR being transmitted during a first part of a RAR window; determine that a radio resource control (RRC) connection request is not received in response to the transmitted first RAR; and upon determining that the RRC connection request is not received in response to the transmitted first RAR, transmit a first plurality of RARs to the UE in a first plurality of time slots during a second part of the RAR window after the first part of the RAR window.

[0155] Example 27 is the apparatus of Example 26, wherein the at least one processor is further configured to: determine that a second RRC connection request in response to the transmitted first plurality of RARs is not received; and upon determining that the second RRC connection request in response to the transmitted first plurality of RARs is not received, transmit a second plurality of RARs to the UE in a second plurality of time slots during a third portion of the RAR window after the second portion of the RAR window, wherein the second plurality of time slots includes a greater number of time slots than the first plurality of time slots.

[0156] Example 28 is the apparatus of Example 26 or 27, wherein the at least one processor is further configured to transmit at least one physical downlink control channel (PDCCH) of a physical downlink shared channel (PDSCH) that schedules transmission of the first plurality of RARs.

[0157] Example 29 is the apparatus of Example 28, wherein the at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during a second configured segment of the RAR window after the first configured segment of the RAR window.

[0158] Example 30 is the apparatus of Example 28, wherein the at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during the first configured segment of the RAR window.

Claims

1. A wireless communication method of a device at a user equipment (UE), the method comprising: receiving, from a base station, a first repetition configuration associated with a first portion of a random access response (RAR) window and a second repetition configuration associated with a second portion of the RAR window, the second portion of the RAR window being different from the first portion of the RAR window, the first repetition configuration and the second repetition configuration indicating different numbers of RAR repetitions configured between the first portion of the RAR window and the second portion of the RAR window; transmitting a preamble for initiating a random access channel (RACH) procedure to the base station; determining that a first RAR is not successfully received after transmitting the preamble; receiving, from the base station, a first plurality of RARs in a first plurality of time slots during the first portion of the RAR window based on the first repetition configuration; determining whether the first plurality of RARs are not successfully received; as well as When the first plurality of RARs are not successfully received, a second plurality of RARs are received from the base station in a second plurality of time slots during the second portion of the RAR window based on the second repetition configuration.

2. The method of claim 1, further comprising: combining the first plurality of RARs into a combined RAR; Decoding the combined RAR; as well as A radio resource control (RRC) connection request responsive to the combined RAR is transmitted to the base station.

3. The method of claim 1 , wherein determining whether the first plurality of RARs are not successfully received comprises: The first plurality of RARs is unsuccessfully decoded, wherein the second plurality of time slots includes a greater number of time slots than the first plurality of time slots.

4. The method of claim 1, further comprising receiving at least one physical downlink control channel (PDCCH) scheduling a physical downlink shared channel (PDSCH) for receiving the first plurality of RARs.

5. The method of claim 4, wherein: The at least one PDCCH is received during a first configured segment of the RAR window, and the first plurality of RARs are received during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window.

6. The method of claim 4, wherein: The at least one PDCCH is received during a first configured segment of the RAR window, and the first plurality of RARs are received during the first configured segment of the RAR window.

7. The method of claim 1, further comprising receiving a configuration indicating a frequency hopping pattern for receiving the first plurality of RARs, the configuration being received through one of downlink control information (DCI) or system information, the first plurality of RARs being received based on the received configuration.

8. The method of claim 1, further comprising receiving a configuration indicating whether RAR repetition is configured, the configuration being received through one of a master information block (MIB) or system information, wherein the first plurality of RARs is received based on the received configuration.

9. The method of claim 1 , further comprising receiving a configuration indicating at least one of: a partition of the RAR window for RAR repetition, a segment within the RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segment, the configuration being received via one of a master information block (MIB), system information, or a radio resource control (RRC) message, wherein the first plurality of RARs is received based on the received configuration.

10. An apparatus for wireless communication, the apparatus being a device at a user equipment (UE), the apparatus comprising: Memory; as well as at least one processor coupled to the memory and configured to: receiving, from a base station, a first repetition configuration associated with a first portion of a random access response (RAR) window and a second repetition configuration associated with a second portion of the RAR window, the second portion of the RAR window being different from the first portion of the RAR window, the first repetition configuration and the second repetition configuration indicating different numbers of RAR repetitions configured between the first portion of the RAR window and the second portion of the RAR window; transmitting a preamble for initiating a random access channel (RACH) procedure to the base station; determining that a first RAR is not successfully received after transmitting the preamble; receiving a plurality of RARs from the base station in a first plurality of time slots during the first portion of the RAR window based on the first repetition configuration; determining whether the first plurality of RARs are not successfully received; as well as When the first plurality of RARs are not successfully received, a second plurality of RARs are received from the base station in a second plurality of time slots during the second portion of the RAR window based on the second repetition configuration.

11. The device of claim 10, wherein: The at least one processor is further configured to: combining the first plurality of RARs into a combined RAR; decoding the combined RAR; and A radio resource control (RRC) connection request responsive to the combined RAR is transmitted to the base station.

12. The device of claim 10, wherein: The at least one processor is configured to determine that the first RAR was not successfully received comprises unsuccessfully decoding the first plurality of RARs, wherein the second plurality of time slots comprises a greater number of time slots than the first plurality of time slots.

13. The device of claim 10, wherein: The at least one processor is further configured to receive at least one physical downlink control channel (PDCCH) scheduled for receiving a physical downlink shared channel (PDSCH) of the first plurality of RARs.

14. The device of claim 13, wherein: The at least one PDCCH is received during a first configured segment of the RAR window, and the plurality of RARs are received during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window.

15. The device of claim 13, wherein: The at least one PDCCH is received during a first configured segment of the RAR window, and the first plurality of RARs are received during the first configured segment of the RAR window.

16. A wireless communication method of a device at a base station (BS), the method comprising: transmitting, to a user equipment (UE), a first repetition configuration associated with a first portion of a random access response (RAR) window and a second repetition configuration associated with a second portion of the RAR window, the second portion of the RAR window being different from the first portion of the RAR window, the first repetition configuration and the second repetition configuration indicating different numbers of RAR repetitions configured between the first portion of the RAR window and the second portion of the RAR window; receiving a preamble for initiating a random access channel (RACH) procedure from the UE; In response to receiving the preamble, transmitting a first RAR to the UE, the first RAR being transmitted during a third portion of the RAR window; determining that a radio resource control (RRC) connection request is not received in response to the transmitted first RAR; transmitting, based on the first repetition configuration, to the UE a first plurality of RARs, the first plurality of RARs being transmitted in a first plurality of time slots during the first portion of the RAR window subsequent to the third portion of the RAR window upon determining that the RRC connection request in response to the transmitted first RARs is not received; determining that a second RRC connection request in response to the transmitted first plurality of RARs is not received; as well as A second plurality of RARs are transmitted to the UE in a second plurality of time slots during the second portion of the RAR window based on the second repetition configuration.

17. The method of claim 16, wherein the second plurality of time slots comprises a greater number of time slots than the first plurality of time slots.

18. The method of claim 16, further comprising at least one physical downlink control channel (PDCCH) that transmits a physical downlink shared channel (PDSCH) that schedules transmissions for the first plurality of RARs.

19. The method of claim 18, wherein: The at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window.

20. The method of claim 18, wherein: The at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during the first configured segment of the RAR window.

21. The method of claim 16, further comprising transmitting a configuration indicating a frequency hopping pattern for transmitting the first plurality of RARs, the configuration being transmitted through one of downlink control information (DCI) or system information, the first plurality of RARs being transmitted based on the transmitted configuration.

22. The method of claim 16, further comprising transmitting a configuration indicating whether RAR repetition is configured, the configuration being transmitted through one of a master information block (MIB) or system information, wherein the first plurality of RARs is transmitted based on the transmitted configuration.

23. The method of claim 16, further comprising transmitting a configuration indicating at least one of: a partition of the RAR window for RAR repetition, a segment within the RAR window for RAR repetition, or a number of RAR repetitions for each RAR window partition or segment, the configuration being transmitted via one of a master information block (MIB), system information, or an RRC message, wherein the first plurality of RARs is transmitted based on the transmitted configuration.

24. An apparatus for wireless communication, the apparatus being a device at a base station (BS), the apparatus comprising: Memory; as well as at least one processor coupled to the memory and configured to: transmitting, to a user equipment (UE), a first repetition configuration associated with a first portion of a random access response (RAR) window and a second repetition configuration associated with a second portion of the RAR window, the second portion of the RAR window being different from the first portion of the RAR window, the first repetition configuration and the second repetition configuration indicating different numbers of RAR repetitions configured between the first portion of the RAR window and the second portion of the RAR window; receiving a preamble for initiating a random access channel (RACH) procedure from the UE; In response to receiving the preamble, transmitting a first RAR to the UE, the first RAR being transmitted during a third portion of the RAR window; determining that a radio resource control (RRC) connection request is not received in response to the transmitted first RAR; transmitting, based on the first repetition configuration, to the UE a first plurality of RARs, the first plurality of RARs being transmitted in a first plurality of time slots during the first portion of the RAR window subsequent to the third portion of the RAR window upon determining that the RRC connection request in response to the transmitted first RARs is not received; determining that a second RRC connection request in response to the transmitted first plurality of RARs is not received; as well as A second plurality of RARs are transmitted to the UE in a second plurality of time slots during the second portion of the RAR window based on the second repetition configuration.

25. The apparatus of claim 24, wherein the second plurality of time slots comprises a greater number of time slots than the first plurality of time slots.

26. The apparatus of claim 24, wherein: The at least one processor is further configured to transmit at least one physical downlink control channel (PDCCH) scheduling a physical downlink shared channel (PDSCH) for transmission of the first plurality of RARs.

27. The device of claim 26, wherein: The at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during a second configured segment of the RAR window subsequent to the first configured segment of the RAR window.

28. The apparatus of claim 26, wherein: The at least one PDCCH is transmitted during a first configured segment of the RAR window, and the first plurality of RARs are transmitted during the first configured segment of the RAR window.

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