Improved Monitoring of Random Access

Abstract

Aspects relate to a configurable monitoring window duration for random access. In some examples, a reduced monitoring window duration may be utilized by a user equipment (UE) to monitor random access messages transmitted by a base station. The reduced monitoring window duration may be configured as an offset from the transmission time of a first random access message by the UE or as a reduced time duration as measured from the transmission time of the first random access message. The configurable monitoring window duration may be associated with a random access response monitoring window, a random access contention resolution monitoring window, or a random access msgB response window.

Description

Technical Field

[0001] The techniques described below generally relate to wireless communication networks, and more particularly, to techniques for monitoring random access messages.

Background Art

[0002] In a 5G new radio wireless communication network, in order for a user equipment (UE) to obtain access to a cell either initially or after a link failure, the UE may perform a random access procedure on a physical random access channel (PRACH). In an example of a random access procedure, the UE may transmit a first random access message to a base station that includes a request for initial access. For example, the UE may randomly select a PRACH preamble from the available set of preambles within the cell served by the base station and transmit the selected PRACH preamble in a RACH occasion (e.g., the time-frequency resource allocated for the first random access message). Upon successful reception of the PRACH preamble, the base station may transmit a second random access message (e.g., a random access response) that includes an identifier of the preamble sent by the UE, a timing advance (TA), a temporary cell radio network temporary identifier (TC-RNTI) or a random access (RA) RNTI for the UE, and a grant for the allocated uplink (UL) resource.

[0003] The random access procedure implemented in a cell may be referred to as a two-step RACH procedure or a four-step RACH procedure. In the four-step RACH procedure, since the preamble is randomly selected by the UE, if another UE selects the same preamble in the same RACH occasion, a collision may occur between the two scheduled entities. Any collision can then be resolved using a contention resolution procedure, in which the UE transmits a third random access message (e.g., an uplink message) containing the UE's identifier, using the TA and the allocated uplink resources in the second random access message. Upon successful decoding of the third random access message, the base station transmits a fourth random access message (e.g., a contention resolution message) containing the UE's identifier. The four-step RACH procedure can be compressed into a two-step RACH procedure by the UE transmitting a combined first random access message that includes the RACH preamble and an uplink message for contention resolution. The base station can then respond with a combined second random access message that includes a random access response and a contention resolution message.

Summary of the Invention

Means for Solving the Problems

[0004] The following presents an overview of such aspects in order to provide a basic understanding of one or more aspects of the present disclosure. This overview is not an extensive overview of all contemplated features of the present disclosure, nor does it identify the main or important elements of all aspects of the present disclosure, nor does it delimit the scope of any or all aspects of the present disclosure. Its sole purpose is to present some concepts of one or more aspects of the present disclosure in a form as a prelude to the more detailed description presented later.

[0005] In one example, a method of wireless communication in a user equipment (UE) is disclosed. The method includes transmitting a first random access message to a base station during a random access procedure, and selecting a monitored window from at least a first monitored window and a second monitored window. The first monitored window includes a first duration that is different from a second duration of the second monitored window. The method further includes monitoring for a second random access message from the base station within the selected monitored window.

[0006] Another example provides a method of wireless communication in a base station. The method includes receiving a first random access message from a user equipment (UE) during a random access procedure, and selecting a monitored window from at least a first monitored window and a second monitored window. The first monitored window includes a first duration that is different from a second duration of the second monitored window. The method further includes transmitting a second random access message to the UE within the selected monitored window.

[0007] These and other aspects of the invention will be more fully understood upon consideration of the following detailed description of the invention. Upon review of the following detailed description of specific exemplary embodiments of the invention, in conjunction with the accompanying drawings, other aspects, features, and embodiments of the invention will become apparent to those of ordinary skill in the art. Although the features of the invention may be described below with reference to several embodiments and figures, all embodiments of the invention can include one or more of the advantageous features described herein. In other words, while one or more embodiments may be described as having several advantageous features, one or more of such features may also be used in accordance with various embodiments of the invention described herein. Similarly, while exemplary embodiments may be described below as device embodiments, system embodiments, or method embodiments, it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.

Brief Description of the Drawings

[0008]

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[0009] The following description of the embodiments for carrying out the invention with reference to the accompanying drawings describes various configurations, and does not represent the only configuration in which the concepts described in this specification can be practiced. The embodiments for carrying out the invention include specific details for providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0010] In this application, several examples will be illustrated for aspects and embodiments. Those skilled in the art will understand that additional implementation forms and use cases may occur in many different configurations and scenarios. The innovations described herein can be implemented across many different platform types, devices, systems, shapes, sizes, and packaging configurations. For example, embodiments and / or applications can occur via integrated chip embodiments and other non-module component-based devices (such as end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchase devices, medical devices, AI-enabled devices, etc.). Some examples may or may not specifically target use cases or application examples, but a wide variety of applicability of the described innovations can occur. Implementations can range from chip-level or modular components to non-modular and non-chip-level implementations, and even to aggregated, distributed, or OEM devices or systems that incorporate one or more aspects of the described innovations. In some practical settings, devices incorporating the described aspects and features may also necessarily include additional components and features for the implementation and practice of the claimed and described embodiments. For example, the transmission and reception of wireless signals necessarily includes several components (such as hardware components including antennas, RF chains, power amplifiers, modulators, buffers, processors, interleavers, adders / summers, etc.) for analog and digital applications. It is intended that the innovations described herein can be practiced in a wide variety of devices, chip-level components, systems, distributed configurations, end-user devices, etc. of various sizes, shapes, and structures.

[0011] The various concepts presented throughout this disclosure may be implemented across a wide variety of telecommunications systems, network architectures, and communication standards. Referring now to FIG. 1, and by way of non-limiting, illustrative example, various aspects of the present disclosure are shown with respect to a wireless communication system 100. The wireless communication system 100 includes three interacting areas: a core network 102, a radio access network (RAN) 104, and a user equipment (UE) 106. The wireless communication system 100 enables the UE 106 to perform data communication with an external data network 110, such as the Internet (but not limited thereto).

[0012] The RAN 104 may implement one or more any suitable radio access technology (RAT) to provide wireless access to the UE 106. As an example, the RAN 104 may operate according to the Third Generation Partnership Project (3GPP™) New Radio (NR) specifications, often referred to as 5G. As another example, the RAN 104 may operate under a hybrid of 5G NR and the evolved Universal Terrestrial Radio Access Network (eUTRAN) standard, often referred to as LTE. 3GPP™ refers to this hybrid RAN as the next generation RAN, or NG-RAN. In another example, the RAN 104 may operate according to both the LTE standard and the 5G NR standard. Of course, within the scope of the present disclosure, many other examples may be utilized.

[0013] As shown, RAN 104 includes a plurality of base stations 108. Broadly speaking, a base station is a network element within a radio access network that is responsible for wireless transmission and reception in one or more cells to or from a UE. In different technologies, standards, or contexts, a base station may be variously referred to by those skilled in the art as a base transceiver station (BTS), radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), access point (AP), Node B (NB), eNode B (eNB), gNode B (gNB), transmit receive point (TRP), or some other suitable term. In some examples, a base station may include two or more TRPs that may or may not be collocated. Each TRP may communicate at the same or different carrier frequencies within the same or different frequency bands. In an example where RAN 104 operates according to both the LTE standard and the 5G NR standard, one of the base stations 108 may be an LTE base station and another base station may be a 5G NR base station.

[0014] Wireless access network 104 is further illustrated to support wireless communication for a plurality of mobile devices. The mobile device may be referred to as a user equipment (UE) 106 in the 3GPP standard, but may also be called a mobile station (MS), subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal (AT), mobile terminal, wireless terminal, remote terminal, handset, terminal, user agent, mobile client, client, or some other suitable term by those skilled in the art. UE 106 may be a device that provides a user with access to network services. In an example where RAN 104 operates according to both the LTE standard and the 5G NR standard, UE 106 may be an evolved universal terrestrial radio access network - new radio dual connectivity (EN-DC) UE that is capable of simultaneously connecting to both an LTE base station and an NR base station to receive data packets from both the LTE base station and the NR base station.

[0015] In this document, a "mobile" device does not necessarily have to have the ability to move and may be stationary. The term mobile device or mobile apparatus broadly refers to a wide variety of devices and technologies. A UE may include some hardware structural components sized, shaped, and arranged to assist in communication, such components can include an antenna, an antenna array, an RF chain, an amplifier, one or more processors, etc. that are electrically coupled to each other. For example, some non-limiting examples of mobile devices include mobile, cellular (cell) phones, smartphones, Session Initiation Protocol (SIP) phones, laptops, personal computers (PCs), notebooks, netbooks, smartbooks, tablets, personal digital assistants (PDAs), and a wide range of embedded systems corresponding to, for example, the "Internet of Things". Additionally, mobile devices can be automobiles or other transportation vehicles, remote sensors or actuators, robots or robotic devices, satellite radios, Global Positioning System (GPS) devices, object tracking devices, drones, multicopters, quadcopters, remote control devices, consumer and / or wearable devices, such as eyewear, wearable cameras, virtual reality devices, smartwatches, health or fitness trackers, digital audio players (e.g., MP3 players), cameras, game consoles, etc. Additionally, mobile devices can be digital home devices or smart home devices such as home audio, video, and / or multimedia devices, appliances, vending machines, intelligent lighting, home security systems, smart meters, etc. Additionally, mobile devices can be smart energy devices, security devices, solar panels or solar arrays, urban infrastructure devices that control power (e.g., smart grids), lighting, water supply, etc., industrial automation and enterprise devices, logistics controllers, agricultural equipment, etc. Even further, mobile devices can provide support for connected healthcare or telemedicine, i.e., remote healthcare.Telemedicine devices may include telemedicine monitoring devices and telemedicine operation devices, and these communications may be given preferential handling or privileged access rights over other types of information, for example, for preferential access for the transport of important service data and / or for related QoS for the transport of important service data.

[0016] The wireless communication between RAN104 and UE106 can be described as using an air interface. Transmissions via the air interface from a base station (for example, base station 108) to one or more UEs (for example, UE106) may be called downlink (DL) transmissions. According to some aspects of the present disclosure, the term downlink may refer to point-to-multipoint transmissions originating at a scheduling entity (for example, base station 108), which will be further described below. Another way to describe this method may be to use the term broadcast channel multiplexing. Transmissions from a UE (for example, UE106) to a base station (for example, base station 108) may be called uplink (UL) transmissions. According to a further aspect of the present disclosure, the term uplink may refer to point-to-point transmissions originating at a scheduled entity (for example, UE106), which will be further described below.

[0017] In some examples, access to the air interface may be scheduled, and a scheduling entity (for example, base station 108) may allocate resources for communication among some or all of the devices and apparatuses within its service area or cell. Within the present disclosure, as will be further described below, a scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources to one or more scheduled entities. That is, for scheduled communication, UE106, which can be a scheduled entity, may utilize the resources allocated by scheduling entity 108.

[0018] Base station 108 is not the only entity that can function as a scheduling entity. That is, in some examples, a UE can function as a scheduling entity that schedules resources for one or more scheduled entities (e.g., one or more other UEs).

[0019] As shown in FIG. 1, scheduling entity 108 can broadcast downlink traffic 112 to one or more scheduled entities 106. Generally, scheduling entity 108 is a node or device responsible for scheduling traffic in a wireless communication network, including downlink traffic 112 and, in some examples, uplink traffic 116 from one or more scheduled entities 106 to scheduling entity 108. On the other hand, scheduled entity 106 is a node or device that receives downlink control information 114, including but not limited to scheduling information (e.g., grants), synchronization or timing information, or other control information, from another entity in a wireless communication network such as scheduling entity 108.

[0020] In addition, uplink and / or downlink control information and / or traffic information may be time-division multiplexed in frames, subframes, slots, and / or symbols. As used herein, a symbol may refer to a unit of time that carries one resource element (RE) per subcarrier in an orthogonal frequency division multiplexing (OFDM) waveform. A slot can carry 7 or 14 OFDM symbols. A subframe may refer to a duration of 1 ms. Multiple subframes or slots may be grouped together to form a single frame or radio frame. Of course, these definitions are not essential, and any suitable manner for organizing the waveform may be utilized, and various time divisions of the waveform may have any suitable duration.

[0021] Generally, base station 108 may include a backhaul interface for communication with the backhaul portion 120 of the wireless communication system. Backhaul 120 may provide a link between base station 108 and core network 102. Further, in some examples, the backhaul network may provide an interconnection between respective base stations 108. Any suitable transport network may be used, and various types of backhaul interfaces may be employed, such as direct physical connections, virtual networks, etc.

[0022] Core network 102 may be part of wireless communication system 100 and may be independent of the radio access technology used in RAN 104. In some examples, core network 102 may be configured according to 5G standards (e.g., 5GC). In other examples, core network 102 may be configured according to 4G evolved packet core (EPC) or any other suitable standard or configuration.

[0023] Referring now to FIG. 2, by way of example and not limitation, a schematic diagram of RAN 200 is provided. In some examples, RAN 200 may be the same as RAN 104 described above and shown in FIG. 1. The geographic area covered by RAN 200 may be divided into cellular regions (cells) that can be uniquely identified by user equipment (UE) based on the identification information broadcast from one access point or base station. FIG. 2 shows macrocells 202, 204, and 206, as well as small cell 208, each of which may include one or more sectors (not shown). A sector is a sub - area of a cell. All sectors within one cell are served by the same base station. The radio link within a sector may be identified by a single logical identification information belonging to that sector. In a cell divided into sectors, a plurality of sectors within the cell may be formed by a group of antennas, and each antenna is responsible for communication with UEs in a part of the cell.

[0024] In FIG. 2, two base stations 210 and 212 are shown within cells 202 and 204, and a third base station 214 that controls a remote radio head (RRH) 216 within cell 206 is shown. That is, a base station can have an integrated antenna or can be connected to an antenna or RRH by a feeder cable. In the illustrated example, since base stations 210, 212, and 214 support cells of a large size, cells 202, 204, and 206 may be referred to as macro cells. Further, a base station 218 is shown within a small cell 208 (e.g., a micro cell, a pico cell, a femto cell, a home base station, a home node B, a home e-node B, etc.) that may overlap one or more macro cells. In this example, since base station 218 supports a cell of a relatively small size, cell 208 may be referred to as a small cell. Cell sizing can be done according to system design as well as component constraints.

[0025] It should be understood that the wireless access network 200 can include any number of wireless base stations and cells. Further, relay nodes may be deployed to extend the size or coverage area of a given cell. Base stations 210, 212, 214, 218 provide a wireless access point to a core network for any number of mobile devices. In some examples, base stations 210, 212, 214, and / or 218 can be the same as the base station / scheduling entity 108 described above and shown in FIG. 1.

[0026] Within RAN 200, a cell may include UEs that are communicating with one or more sectors of each cell. Further, each base station 210, 212, 214, and 218 may be configured to provide an access point to the core network 102 (see FIG. 1) for all UEs within their respective cells. For example, UEs 222 and 224 may be communicating with base station 210, UEs 226 and 228 may be communicating with base station 212, UEs 230 and 232 may be communicating with base station 214 via RRH 216, and UE 234 may be communicating with base station 218. In some examples, UEs 222, 224, 226, 228, 230, 232, 234, 238, 240, and / or 242 may be the same as the UE / scheduled entity 106 described above and shown in FIG. 1.

[0027] In some examples, an unmanned aerial vehicle (UAV) 220, which may be a drone or quadcopter, may be a mobile network node and may be configured to function as a UE. For example, UAV 220 may operate within cell 202 by communicating with base station 210.

[0028] In the radio access network 200, the ability of a UE to communicate while moving, regardless of its location, is referred to as mobility. The various physical channels between the UE and the radio access network are generally set up, maintained, and released under the control of an access and mobility management function (AMF, not shown, part of the core network 102 in FIG. 1), which may include a security context management function (SCMF) that manages the security context for both control plane and user plane functionality, and a security anchor function (SEAF) that performs authentication.

[0029] The wireless access network 200 may utilize DL-based mobility or UL-based mobility to enable mobility and handover (i.e., the transfer of a UE's connection from one radio channel to another). In a network configured for DL-based mobility, during a call using a scheduling entity, or at any other time, the UE may monitor various parameters of signals from its serving cell, as well as various parameters of neighboring cells. Depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if the signal quality from a neighboring cell exceeds the signal quality from the serving cell over a given amount of time, the UE may initiate a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE 224 (shown as a vehicle, although any suitable form of UE may be used) may move from the geographical area corresponding to its serving cell 202 to the geographical area corresponding to neighbor cell 206. When the signal strength or quality from neighbor cell 206 exceeds the signal strength or quality of its serving cell 202 over a given amount of time, UE 224 may send a report message indicating this condition to its serving base station 210. In response, UE 224 may receive a handover command, and the UE may undergo a handover to cell 206.

[0030] In a network configured for UL-based mobility, UL reference signals from each UE can be utilized by the network to select a serving cell for each UE. In some examples, base stations 210, 212, and 214 / 216 may broadcast combined synchronization signals (e.g., combined primary synchronization signal (PSS), combined secondary synchronization signal (SSS), and combined physical broadcast channel (PBCH)). UEs 222, 224, 226, 228, 230, and 232 may receive the combined synchronization signals, derive carrier frequency and slot timing from the synchronization signals, and transmit an uplink pilot or reference signal in response to the derived timing. An uplink pilot signal transmitted by a UE (e.g., UE 224) may be simultaneously received by two or more cells (e.g., base stations 210 and 214 / 216) within the radio access network 200. Each of the cells may measure the strength of the pilot signal, and the radio access network (e.g., one or more of base stations 210 and 214 / 216, and / or a central node within the core network) may determine a serving cell for UE 224. As UE 224 moves through the radio access network 200, the network can continue to monitor the uplink pilot signal transmitted by UE 224. When the signal strength or quality of the pilot signal measured by a neighboring cell exceeds the signal strength or quality measured by the serving cell, the network 200 may notify UE 224 or hand over UE 224 from the serving cell to a neighboring cell without notification.

[0031] The synchronization signals transmitted by base stations 210, 212, and 214 / 216 can be integrated, but the synchronization signals may not identify a specific cell. Instead, they can identify zones of multiple cells operating on the same frequency and / or using the same timing. The use of zones in a 5G network or other next-generation communication network enables an uplink-based mobility framework and improves the efficiency of both the UE and the network because the number of mobility messages that need to be exchanged between the UE and the network can be reduced.

[0032] In various implementations, the air interface in radio access network 200 can utilize licensed spectrum, unlicensed spectrum, or shared spectrum. Licensed spectrum generally provides exclusive use of a portion of the spectrum by a mobile network operator purchasing a license from a government regulatory agency. Unlicensed spectrum provides shared use of a portion of the spectrum without the need for a license permitted by the government. Compliance with some technical rules is generally still required to access unlicensed spectrum, but generally any operator or device can obtain access. Shared spectrum can be in between licensed and unlicensed spectrum, and technical rules or restrictions may be required to access the spectrum, but the spectrum can still be shared by multiple operators and / or multiple RATs. For example, the holder of a license for a portion of licensed spectrum can provide Licensed Shared Access (LSA) that is authorized to share that spectrum with other parties, for example, with conditions determined by a suitable license for access.

[0033] In some examples, access to the air interface may be scheduled, where a scheduling entity (e.g., a base station) allocates communication resources (e.g., time-frequency resources) among some or all of the devices and apparatuses within its service area or cell. Within the present disclosure, as further described below, the scheduling entity may be responsible for scheduling, allocating, reconfiguring, and releasing resources to one or more scheduled entities. That is, for scheduled communication, a UE or a scheduled entity utilizes resources allocated by the scheduling entity.

[0034] The base station is not the only entity that can function as a scheduling entity. That is, in some examples, a UE can function as a scheduling entity that schedules resources for one or more scheduled entities (e.g., one or more other UEs). For example, two or more UEs (e.g., UE238, 240, and 242) can communicate with each other using peer-to-peer (P2P) or sidelink signals 237 without relaying their communication through a base station. In some examples, UE238, 240, and 242 can each function as a scheduling entity or a transmitting sidelink device and / or a scheduled entity or a receiving sidelink device to schedule resources and communicate sidelink signals 237 among themselves without relying on scheduling or control information from the base station. In other examples, two or more UEs (e.g., UE226 and 228) within the coverage area of a base station (e.g., base station 212) may communicate sidelink signals 227 via a direct link (sidelink) without relaying their communication through base station 212. In this example, base station 212 may allocate resources to UE226 and 228 for sidelink communication. In any case, such sidelink signaling 227 and 237 can be implemented in a P2P network, a device-to-device (D2D) network, a vehicle-to-vehicle (V2V) network, a vehicle-to-everything (V2X), a mesh network, or other suitable direct link network.

[0035] In some examples, a D2D relay framework may be included within a cellular network to facilitate communication relay between a base station 212 via a D2D link (e.g., sidelink 227 or 237). For example, one or more UEs (e.g., UE 228) within the coverage area of base station 212 may act as a relay UE to extend the coverage of base station 212, improve transmission reliability to one or more UEs (e.g., UE 226), and / or, for example, enable the base station to recover from a UE link that has failed due to interference or fading.

[0036] The air interface in the wireless access network 200 may utilize one or more duplexing algorithms. Duplexing refers to a point-to-point communication link where both endpoints can communicate with each other in both directions. Full duplex means that both endpoints can communicate with each other simultaneously. Half duplex means that only one endpoint can send information to the other at a time. Half-duplex emulation is frequently implemented for wireless links using time-division duplexing (TDD). In TDD, transmissions in different directions on a given channel are separated from each other using time-division multiplexing. That is, at a certain time, the channel is dedicated to transmission in one direction, but at other times, the channel is dedicated to transmission in the other direction, and in that case, the direction can change very rapidly, for example, several times per slot. In a wireless link, a full-duplex channel generally relies on physical separation of the transmitter and receiver, as well as suitable interference cancellation techniques. Full-duplex emulation is frequently implemented for wireless links by utilizing frequency-division duplexing (FDD) or space-division duplexing (SDD). In FDD, transmissions in different directions may operate at different carrier frequencies (e.g., within a paired spectrum). In SDD, transmissions in different directions on a given channel are separated from each other using space-division multiplexing (SDM). In other examples, full-duplex communication may be implemented within an asymmetric spectrum (e.g., within a single carrier bandwidth), where transmissions in different directions occur within different sub-bands of the carrier bandwidth. This type of full-duplex communication is sometimes referred to in this specification as sub-band full duplex (SBFD), also known as flexible duplexing.

[0037] The air interface in the wireless access network 200 may further utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of various devices. For example, the 5G NR specification provides multiple access for UL transmissions from UEs 222 and 224 to the base station 210 and for multiplexing DL transmissions from the base station 210 to one or more UEs 222 and 224 that utilize orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP). In addition, for UL transmissions, the 5G NR specification provides support for discrete Fourier transform spread OFDM (DFT-s-OFDM) (also referred to as single carrier FDMA (SC-FDMA)) with CP. However, within the scope of the present disclosure, multiplexing and multiple access are not limited to the above-described methods and may be performed using time division multiple access (TDMA), code division multiple access (CDMA), frequency division multiple access (FDMA), sparse code multiple access (SCMA), resource spread multiple access (RSMA), or other suitable multiple access methods. Further, multiplexing DL transmissions from the base station 210 to UEs 222 and 224 may be performed using time division multiplexing (TDM), code division multiplexing (CDM), frequency division multiplexing (FDM), orthogonal frequency division multiplexing (OFDM), sparse code multiplexing (SCM), or other suitable multiplexing methods.

[0038] Various aspects of the present disclosure are described with reference to the OFDM waveform, and an example of the OFDM waveform is schematically shown in FIG. 3. Those skilled in the art should understand that various aspects of the present disclosure may be applied to the SC-FDMA waveform in substantially the same manner as described hereinafter in this specification. That is, some examples of the present disclosure may focus on the OFDM link for clarity, but it should be understood that the same principles may equally apply to the SC-FDMA waveform.

[0039] Referring now to FIG. 3, an enlarged view of an exemplary DL subframe 302 is illustrated, showing an OFDM resource grid. However, as will be readily appreciated by those skilled in the art, the PHY transmission structure for any particular application example may vary from the examples described herein depending on any number of factors. Here, time is in the horizontal direction in units of OFDM symbols, and frequency is in the vertical direction in units of subcarriers.

[0040] Resource grid 304 can be used to schematically represent the time-frequency resources for a given antenna port. That is, in a multiple-input multiple-output (MIMO) implementation with a plurality of available antenna ports, a corresponding plurality of resource grids 304 may be available for communication. Resource grid 304 is divided into a plurality of resource elements (REs) 306. An RE, which is 1 subcarrier × 1 symbol, is the smallest individual part of the time-frequency grid and contains a single complex quantity representing data from a physical channel or signal. Depending on the modulation utilized in a particular implementation, each RE may represent one or more bits of information. In some examples, a block of REs may be referred to as a physical resource block (PRB) or more simply a resource block (RB) 308, which includes any suitable number of contiguous subcarriers in the frequency domain. In one example, an RB may include 12 subcarriers, a number independent of the numerology used. In some examples, depending on the numerology, an RB may include any suitable number of contiguous OFDM symbols in the time domain. Within the present disclosure, it is assumed that a single RB, such as RB 308, fully corresponds to a single direction of communication (either transmission or reception for a given device).

[0041] Scheduling of a UE or a side-link device (collectively referred to as UE below) for downlink, uplink, or side-link transmission typically involves scheduling one or more resource elements 306 within one or more sub-bands or bandwidth parts (BWPs). Thus, the UE generally utilizes only a subset of the resource grid 304. In some examples, an RB can be the smallest unit of resources that can be allocated to the UE. Thus, the more RBs scheduled for the UE and the higher the modulation scheme selected for the air interface, the higher the data rate of the UE. The RBs can be scheduled by a base station (e.g., gNB, eNB, etc.) or self-scheduled by the UE / side-link device implementing D2D side-link communication.

[0042] In this figure, RB 308 is shown as occupying less than the entire bandwidth of subframe 302, and some sub-carriers are shown above and below RB 308. In a given implementation, subframe 302 can have a bandwidth corresponding to any number of one or more RBs 308. Further, in this figure, RB 308 is shown as occupying less than the entire duration of subframe 302, but this is only one possible example.

[0043] Each 1 ms subframe 302 can consist of one or more adjacent slots. In the example shown in FIG. 4, one subframe 302 includes, as an example for illustration purposes, four slots 310. In some examples, a slot can be defined according to a specified number of OFDM symbols with a given cyclic prefix (CP) length. For example, a slot can include seven or fourteen OFDM symbols with a nominal CP. Additional examples can include mini-slots, sometimes referred to as shortened transmission time intervals (TTIs), having a shorter duration (e.g., one to three OFDM symbols). These mini-slots or shortened transmission time intervals (TTIs) can, in some cases, be transmitted occupying resources scheduled for an ongoing slot transmission for the same UE or different UEs. Any number of resource blocks can be utilized within a subframe or slot.

[0044] An enlarged view of one of the slots 310 shows a slot 310 including a control region 312 and a data region 314. Generally, the control region 312 can carry a control channel (e.g., PDCCH), and the data region 314 can carry a data channel (e.g., PDSCH or PUSCH). Of course, a slot can include all DL, all UL, or at least one DL portion and at least one UL portion. The simple structure shown in FIG. 3 is merely an example in nature, and different slot structures may be utilized and may include one or more of each of the control region and the data region.

[0045] Although not shown in FIG. 3, the various resource elements 306 within a resource block 308 can be scheduled to carry one or more physical channels, including control channels, shared channels, data channels, etc. Other resource elements 306 within the resource block 308 can also carry pilots or reference signals. These pilots or reference signals can enable a receiving device to perform channel estimation of the corresponding channels, which can enable coherent demodulation / detection of control channels and / or data channels within the resource block 308.

[0046] In some examples, slot 310 may be utilized for broadcast, multicast, groupcast, or unicast communication. For example, broadcast, multicast, or groupcast communication may refer to a point-to-multipoint transmission from one device (e.g., a base station, a UE, or other similar device) to other devices. Here, broadcast communication is delivered to all devices, while multicast communication is delivered to a plurality of intended receiving devices, and groupcast communication is delivered to a group of intended receiving devices. Unicast communication may refer to a point-to-point transmission from one device to a single other device.

[0047] In an example of cellular communication over a cellular carrier via a Uu interface, for a DL transmission, a scheduling entity (e.g., a base station) may allocate one or more resource elements (REs) (e.g., within control region 312) for carrying DL control information including one or more DL control channels such as a physical downlink control channel (PDCCH) to one or more scheduled entities (e.g., UEs). The PDCCH may carry downlink control information (DCI) including, but not limited to, power control commands (e.g., one or more open-loop power control parameters and / or one or more closed-loop power control parameters), scheduling information, grants, and / or allocation of REs for DL and UL transmissions. The PDCCH may further carry HARQ feedback transmissions such as an acknowledgement (ACK) or a negative acknowledgement (NACK). HARQ is a technique well known to those skilled in the art, and for the sake of accuracy, packet transmission integrity may be checked at the receiving side using any suitable integrity checking mechanism such as a checksum or a cyclic redundancy check (CRC). If the transmission integrity is confirmed, an ACK may be transmitted, but if not, a NACK may be transmitted. In response to a NACK, the transmitting device may send a HARQ retransmission that may implement techniques such as chase combining, incremental redundancy, etc.

[0048] The base station may further allocate one or more RE306 (e.g., within the control region 312 or the data region 314) to carry other DL signals such as demodulation reference signals (DMRS), phase tracking reference signals (PT-RS), channel state information (CSI) reference signals (CSI-RS), and synchronization signal blocks (SSB). The SSB may be broadcast at regular intervals based on periodicity (e.g., 5, 10, 20, 40, 80, or 160 ms). The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a physical broadcast control channel (PBCH). The UE may utilize the PSS and SSS to achieve radio frame, sub-frame, slot, and symbol synchronization within the time domain, identify the center of the channel (system) bandwidth within the frequency domain, and identify the physical cell identification information (PCI) of the cell.

[0049] The PBCH within the SSB may further include a master information block (MIB) that contains various system information along with parameters for decoding system information blocks (SIB). For example, the SIB may be SystemInformationType 1 (SIB1) that contains various additional system information. Examples of system information transmitted within the MIB may include, but are not limited to, subcarrier spacing, number of system frames, configuration of the physical downlink control channel (PDCCH) control resource set (CORESET) (e.g., PDCCH CORESET0), and search space for SIB1. Examples of additional system information transmitted in SIB1 may include, but are not limited to, random access search space, downlink configuration information, and uplink configuration information. Both the MIB and SIB1 provide the minimum system information (SI) for initial access.

[0050] In UL transmission, a scheduled entity (e.g., a UE) may utilize one or more RE306 to carry UL control information (UCI) including one or more UL control channels such as a physical uplink control channel (PUCCH) to a scheduling entity. The UCI may include various packet types and categories including information configured to enable or assist in decoding pilots, reference signals, and uplink data transmissions. In some examples, the UCI may include a scheduling request (SR), i.e., a request for the scheduling entity to schedule uplink transmission. Here, in response to the SR transmitted on the UCI, the scheduling entity may transmit downlink control information (DCI) that can schedule resources for uplink packet transmission. The UCI may also include HARQ feedback, channel state feedback (CSF) such as CSI reporting, or any other suitable UCI.

[0051] In addition to control information, one or more RE306 (e.g., within data region 314) may be allocated for data traffic. Such data traffic may be carried on one or more traffic channels such as a physical downlink shared channel (PDSCH) for DL transmission or a physical uplink shared channel (PUSCH) for UL transmission. In some examples, one or more RE306 within data region 314 may be configured to carry other signals such as one or more SIBs and DMRS.

[0052] In an example of sidelink communication on a sidelink carrier via a PC5 interface, the control region 312 of slot 310 may include a physical sidelink control channel (PSCCH) that contains sidelink control information (SCI) transmitted by a starting (transmitting) sidelink device (e.g., a V2X or other sidelink device) towards a set of one or more other receiving sidelink devices. The data region 314 of slot 310 may include a physical sidelink shared channel (PSSCH) that contains sidelink data traffic transmitted by the starting (transmitting) sidelink device within the resources reserved on the sidelink carrier by the transmitting sidelink device via the SCI. Other information may be further transmitted on various REs 306 within slot 310. For example, HARQ feedback information may be transmitted from a receiving sidelink device to a transmitting sidelink device within a physical sidelink feedback channel (PSFCH) within slot 310. Additionally, one or more reference signals such as sidelink SSB and / or sidelink CSI-RS may be transmitted within slot 310.

[0053] These physical channels described above are generally multiplexed for processing in the media access control (MAC) layer and mapped to transport channels. The transport channels carry blocks of information called transport blocks (TBs). The transport block size (TBS), which may correspond to the number of bits of information, may be a controlled parameter based on the modulation and coding scheme (MCS) and the number of RBs in a given transmission.

[0054] The channels or carriers shown in FIG. 3 are not necessarily all the channels or carriers that can be used between devices. In addition to those shown, those skilled in the art will recognize that other channels or carriers such as other traffic channels, control channels, and feedback channels can be used.

[0055] To obtain access to a cell, the UE may execute a random access procedure on the Physical Random Access Channel (PRACH). The UE may identify a random access search space including PRACH resources for starting the RACH procedure from SIB1. For example, the random access process may be started after the UE reads the SSB and SIB1, acquires the cell, and determines the occurrence of a RACH occasion (e.g., PRACH resources). The SSB provides initial system information (SI), and SIB1 (and other SIB blocks) provides the remaining minimum SI (RMSI). For example, the PBCH MIB of the SSB may carry the first part of the SI required for the user equipment (UE) to access the network. SIBs (e.g., SIB1 and SIB2) can carry the RMSI required for the UE to obtain access to the network.

[0056] The RACH procedure can be executed in various scenarios such as loss of uplink synchronization, lack of available PUCCH resources, scheduling request failure, and other use cases. In addition, the RACH procedure can be contention-based or contention-free and can include a two-step RACH process (contention-based or contention-free), a three-step RACH process (contention-free), or a four-step RACH process (contention-based).

[0057] FIG. 4 is a diagram showing an example of a four-step contention-based random access (CBRA) procedure 400 between a base station 402 and a UE 404. The base station 402 may correspond to, for example, any of the scheduling entities shown in FIG. 1 and / or FIG. 2. Additionally, the UE 404 may correspond to, for example, any of the scheduled entities shown in FIG. 1 and / or FIG. 2.

[0058] The random access procedure 400 shown in FIG. 4 is initiated by the UE 404 randomly selecting a preamble from the available set of preambles in the cell served by the base station 402 and transmitting the selected preamble to the base station 402 in a RACH preamble message 406 (msg1). In one example, the UE 404 may select from 64 possible preamble sequences to include in the RACH preamble message 406. Msg1 406 may be transmitted by the UE 404 on the selected PRACH resource using power ramping. The selected PRACH resource may include a supplementary uplink resource or a normal uplink resource. Here, the supplementary uplink resource includes a lower frequency resource than the normal uplink resource. Thus, the supplementary uplink resource and the uplink resource each correspond to different respective uplink frequency bands. Msg1 406 may be further communicated on the beam selected by the UE 404 based on beam measurements (e.g., RSRP / RSRQ / SINR) performed by the UE 404. The beam may correspond to, for example, an SSB beam.

[0059] If the base station 402 successfully detects the preamble, the base station 402 transmits a random access response (RAR) message 408 (msg2) including the PDCCH and PDSCH to the UE 404. If msg2 (RAR) 408 is not received within the RAR window, the UE 404 may retransmit msg1 406 using power boosting. Msg2 408 (PDCCH + PDSCH) includes the identifier of the preamble sent by the UE 404, the timing advance (TA), a temporary cell radio network temporary identifier (TC-RNTI) or a random access (RA) RNTI for the UE 404, and permission for the allocated uplink (UL) resources. The PDCCH in msg2 408 may be scrambled with the RA-RNTI, which is a function of the RACH occasion (RO) (e.g., the time-frequency resources allocated for the RACH msg1) used by the UE 404 to send msg1 406. The medium access control-control element (MAC-CE) in the PDSCH provides an acknowledgment response for the reception of msg1 and the UL permission. To receive msg2 408, the UE 404 may monitor DCI 1_0 for the PDCCH scrambled with the RA-RNTI corresponding to the RO used by the UE 404 to send msg1 406, and if detected, proceed with PDSCH decoding. When receiving the RAR message 408, the UE 404 compares the preamble ID with the preamble sent by the scheduled entity in the RACH preamble message 406. If the preamble ID matches the preamble sent in the RACH preamble message 406, the UE 404 applies the timing advance and starts the contention resolution procedure.

[0060] Since the preamble is randomly selected by a scheduled entity, a collision may occur between two scheduled entities if another scheduled entity selects the same preamble in the same RO. Any collision can then be resolved using a contention resolution procedure. During contention resolution, UE 404 uses the TA and the allocated uplink resources in the PDSCH of msg2 408 to transmit an uplink message (msg3) 410 on the common control channel (CCCH). In one example, the uplink message 410 is a layer 2 / layer 3 (L2 / L3) message such as a radio resource control (RRC) connection request message. The uplink message 410 includes the identifier (UE-ID) of UE 404 for use by the scheduling entity in resolving any collision. Other scheduled entities may use the TA and the allocated uplink resources to transmit colliding uplink messages, but these colliding uplink messages may not succeed in decoding at the scheduling entity because the colliding uplink messages were transmitted using a TA not intended for those scheduled entities.

[0061] Upon successful decoding of the uplink message, the base station 402 transmits a contention resolution message 412 (msg4) to UE 404. The contention resolution message 412 can be, for example, an RRC connection setup message. In addition, the contention resolution message 412 includes the identifier of UE 404 received in the uplink message 410. When UE 404 receives its own identification information returned in the contention resolution message 412, it concludes that the random access procedure was successful and completes the RRC connection setup process. Any other scheduled entity that receives the RRC connection setup message along with the identification information of UE 404 will conclude that the random access procedure has failed and will re-initialize the random access procedure.

[0062] The 4-step CBRA procedure 400 can be compressed into the 2-step random access procedure 500 shown in FIG. 5. The 2-step random access procedure 500 reduces the overhead and latency associated with control signaling by removing transmissions in each direction between the UE 504 and a base station or scheduling entity such as the shown gNB 502. Compared with FIG. 4, the 2-step random access procedure 500 starts with a transmission by the UE 504 of a single message (msgA 506) that includes the sent RACH preamble message 406 and uplink message 410 of the contention-based random access procedure 400. Here, the uplink message 410 can be a scheduled PUSCH transmission sent on a PUSCH resource, and the RACH preamble message 406 can be sent on a selected PRACH resource. The gNB 502 responds with a single message (msgB 508) that includes the random access response 408 and contention resolution message 412.

[0063] FIG. 6 is a diagram showing an exemplary monitoring window for random access according to some aspects. In FIG. 6, monitoring windows for both a 4-step random access procedure 602 and a 2-step random access procedure 604 are shown. In the 4-step random access procedure 602, the UE may transmit msg1, which includes, for example, a PRACH preamble message, at a first time (t1), and upon transmitting msg1, may initialize a random access response window 606 for monitoring a random access response (msg2). The UE may further initialize a random access contention resolution window 608 for monitoring a contention resolution message (msg4) upon transmitting msg1. As described above, within the random access response window 606, the UE monitors DCI 1_0 for a PDCCH scrambled with an RA-RNTI corresponding to the RO used by the UE to transmit msg1. If the UE receives msg2 within the random access response window 606 (e.g., at a second time (t2)), the UE may proceed to transmit an uplink message (msg3) at a third time (t3) and then may monitor a contention resolution message (msg4), which may be received, for example, at a fourth time (t4) within the random access contention resolution window 608. If the UE does not receive msg2 within the random access response window 606 or msg4 within the random access contention resolution window 608, the UE may declare a RACH failure and may select a new PRACH preamble to start the random access procedure 602 again.

[0064] In the two-step random access procedure 604, the UE may transmit msgA at a first time (tA), for example, including a PRACH preamble message and an uplink message. When the UE transmits msgA, it may further initialize a random access msgB response window 610 for monitoring msgB. To complete the random access procedure, msgB may be received at a second time (tB) within, for example, the random access msgB response window 610. If the UE does not receive msgB within the random access msgB response window 610, the UE may declare a RACH failure and select a new PRACH preamble to start the random access procedure 604 again.

[0065] A fifth-generation (5G) wireless communication network, such as a new radio (NR) wireless communication network, supports communication between a base station and a high-end UE for multiple different use cases, including, for example, enhanced mobile broadband (eMBB) and ultra-reliable low-latency communication (URLLC). The NR network may further support communication between a base station and a low-end UE in a massive machine type communication (mMTC) use case. In some examples, LTE-M or narrowband Internet of Things (NB-IoT) technology may be utilized to meet the requirements of mMTC.

[0066] When RACH is executed, a significant amount of power is utilized at the UE to monitor response messages, such as msg2 or msg4 in the four-step random access procedure 400, or msgB in the two-step random access procedure 500. For example, the UE monitors each slot within a random access monitoring window (such as windows 606, 608, and 610) for the PDCCH to determine whether there is a random access transmission of a response from the base station (gNB) to the UE (such as msg2 in the four-step random access procedure 400, or msgB in the two-step random access procedure 500).

[0067] For normal high-end UEs and normal traffic, the power consumption for random access monitoring may not be significantly large compared to the overall power consumption utilized by such high-end UEs. However, in the case of IoT devices and other low-end UEs, the power consumption may represent a large proportion of the overall power consumption. This is particularly true for small data transmissions (e.g., short data transmissions), where low-end UEs sometimes transmit a small amount of data and then return to the sleep state, for example, when operating in the discontinuous reception (DRX) mode.

[0068] In both LTE networks and NR networks, the monitoring window duration for random access is fixed, and thus there is no mechanism to reduce the monitoring duration based on UE type (e.g., low-end or high-end) and / or data transmission type (e.g., small data transmission or normal data transmission). For example, in a two-step RACH, the random access msgB response window can be up to 40 ms. The UE needs to monitor the downlink for the entire 40 ms before declaring a RACH failure, regardless of the UE type or data transmission type.

[0069] Accordingly, various aspects of the present disclosure provide a configurable monitoring window for random access. The configurable monitoring window may have a time duration that can be selected based on one or more factors such as UE type or data transmission type. In some examples, the configurable monitoring window may have a reduced duration to limit the time required for the UE to monitor random access messages from the base station. The reduced monitoring window duration may be configured as an offset from the transmission time of the first random access message (e.g., msg1 or msgA) by the UE, or as a reduced time duration as measured from the transmission time of the first random access message.

[0070] FIG. 7 is a block diagram illustrating an example of a hardware implementation for a user equipment (UE) 700 that employs a processing system 714. For example, UE 700 may correspond to any of the UEs or other scheduled entities illustrated and described above with respect to FIGS. 1, 2, 4, and / or 5.

[0071] UE 700 may be implemented using a processing system 714 that includes one or more processors 704. Examples of processors 704 include microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. In various examples, UE 700 may be configured to perform any one or more of the functions described herein. That is, the processor 704 utilized in UE 700 may be used to implement any one or more of the processes and procedures described below.

[0072] In this example, the processing system 714 may be implemented with a bus architecture schematically represented by bus 702. Bus 702 can include any number of interconnecting buses and bridges depending on the specific application of the processing system 714 and overall design constraints. Bus 702 links together various circuits including one or more processors (schematically represented by processor 704), memory 705, and a computer-readable medium (schematically represented by computer-readable medium 706). Bus 702 may also link together various other circuits such as a timing source, peripherals, voltage regulators, and power management circuits, which are well known in the art and, thus, will not be described further herein.

[0073] The bus interface 708 provides an interface between the bus 702 and the transceiver 710 and one or more antenna arrays 730 (e.g., one or more antenna panels). The transceiver 710 provides means for communicating with various other devices via a transmission medium (e.g., an air interface). Depending on the nature of the device, a user interface 712 (e.g., a keypad, a display, a touch screen, a speaker, a microphone, a control knob, etc.) may also be provided. Of course, such a user interface 712 is optional and may be omitted in some instances.

[0074] The processor 704 is responsible for managing the bus 702 and performing general processing including the execution of software stored in the computer-readable medium 706. Software should be broadly construed to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc., whether called by the names software, firmware, middleware, microcode, hardware description language, or other names. When executed by the processor 704, the software causes the processing system 714 to perform various functions described below for any particular device. The computer-readable medium 706 and the memory 705 may also be used to store data that is manipulated by the processor 704 when executing the software.

[0075] The computer-readable medium 706 can be a non-transitory computer-readable medium. Non-transitory computer-readable media include, by way of example, magnetic storage devices (such as hard disks, floppy disks, magnetic strips), optical disks (such as compact discs (CDs) or digital versatile discs (DVDs)), smart cards, flash memory devices (such as cards, sticks, or key drives), random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, and any other suitable medium for storing software and / or instructions that can be accessed and read by a computer. The computer-readable medium 706 may be present within the processing system 714, external to the processing system 714, or distributed across multiple entities including the processing system 714. The computer-readable medium 706 can be embodied in a computer program product. By way of example, the computer program product may include the computer-readable medium within a packaging material. In some examples, the computer-readable medium 706 may be part of the memory 705. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure, depending on the particular application and overall design constraints imposed on the overall system.

[0076] In some aspects of the present disclosure, the processor 704 can include circuitry configured for various functions. For example, the processor 704 can include a communication and processing circuitry configuration 742 configured to communicate with a base station such as a gNB. In some examples, the communication and processing circuitry configuration 742 can include one or more hardware components that provide a physical structure for performing processes related to wireless communication (such as signal reception and / or signal transmission) and signal processing (such as processing of received signals and / or processing of signals for transmission).

[0077] In some examples, the communication and processing circuitry 742 can be configured to transmit random access messages, such as msg1 or msg3 in a 4-step random access procedure, or msgA in a 2-step random access procedure. The communication and processing circuitry 742 can be further configured to receive random access messages, such as msg2 or msg4 in a 4-step random access procedure, or msgB in a 2-step random access procedure. The communication and processing circuitry 742 can be further configured to execute communication and processing instructions (software) 752 stored in the computer-readable medium 706 to implement one or more of the functions described herein.

[0078] The processor 704 may further include a random access circuit configuration 744 configured to perform a random access procedure, such as a 2-step random access procedure or a 4-step random access procedure. In some examples, the random access circuit configuration 744 may be configured to select a PRACH preamble for inclusion in msg1 or msgA, and to generate and transmit msg1 or msgA. The PRACH preamble may be randomly selected from the available set of PRACH preambles configured in the cell. In some examples, the set of PRACH preambles may include two or more subsets of PRACH preambles, each associated with a different monitoring window duration. In some examples, the different monitoring window durations may be configured for different UE types or different data transmission types. For example, a first subset of PRACH preambles may be associated with a first monitoring window duration, and a second subset of PRACH preambles may be associated with a second monitoring window duration, where the first monitoring window duration may be less than the second monitoring window duration. In this example, the random access circuit configuration 744 may select a PRACH preamble from one of the subsets of PRACH preambles based on the type of UE 700 (e.g., low-end or high-end), or the data transmission type (e.g., normal or small data transmission) that will be transmitted by UE 700 after the random access procedure is completed.

[0079] The random access circuit configuration 744 may be further configured to operate with the communication and processing circuit configuration 742 to transmit msg1 or msgA to the base station. In some examples, the random access circuit configuration 744 may select an uplink grant for use in transmitting the PUSCH in msgA based on a desired monitoring window duration. For example, SIB1 may indicate different uplink grants for the PUSCH of msgA for different monitoring window durations. In some examples, the different monitoring window durations may be configured for different UE types or different data transmission types. In this example, the random access circuit configuration 744 may select an uplink grant for the PUSCH of msgA based on the type of UE 700 (e.g., low-end or high-end), or the data transmission type (e.g., normal or small data transmission) that will be transmitted by UE 700 after completing the random access procedure. In some examples, the random access circuit configuration 744 may generate a payload for the PUSCH of msgA having a payload size based on a selected time duration for the random access msgB response monitoring window. For example, the payload size of the PUSCH of msgA may be smaller for a shorter monitoring window duration and larger for a longer monitoring window duration.

[0080] The random access circuit configuration 744 may be further configured to receive and process msg2. In some examples, msg2 may include an indication of a selected monitoring window duration for the random access contention resolution window. For example, msg2 may include a selected time duration for the random access contention resolution window, or an index indicating the selected time duration. The random access circuit configuration 744 may be further configured to monitor msg2 within the random access response monitoring window.

[0081] The random access circuit configuration 744 may be further configured to generate and transmit msg3 in response to receiving an uplink grant for msg3 in msg2. In some examples, the uplink grant provided by the base station may indicate a monitoring window duration for use in a random access contention resolution monitoring window. In other examples, the uplink grant may include a plurality of uplink grants from which the random access circuit configuration 744 can select based on a time duration selected by the UE 700 for a random access contention resolution monitoring window. In some examples, the random access circuit configuration 744 may generate a payload for msg3 having a payload size based on a selected time duration for a random access contention resolution monitoring window. For example, the payload size of msg3 may be smaller for a shorter monitoring window duration and larger for a longer monitoring window duration.

[0082] The random access circuit configuration 744 may be further configured to receive and process msg4 of a 4-step random access procedure or msgB of a 2-step random access procedure. The random access circuit configuration 744 may be further configured to monitor msg4 during a random access contention resolution window and msgB during a random access msgB response window.

[0083] The random access circuit configuration 744 may be further configured to execute a random access procedure during a channel occupancy time (COT) of an unlicensed channel. In this example, the COT may be initiated by the base station, and the monitoring window durations (e.g., a random access response monitoring window, and a random access contention resolution window, or a random access msgB response window) occur within the COT. The random access circuit configuration 744 may be further configured to execute random access instructions (software) 754 stored in a computer-readable medium 706 to implement one or more of the functions described herein.

[0084] When monitoring random access messages from the base station, the processor 704 may further include a random access monitoring window circuit configuration 746 configured to select one or more random access monitoring windows 720 that will be utilized by the random access circuit configuration 744. The random access monitoring window 720 may include one or more of a random access response window for monitoring msg2, a random access msgB response window for monitoring msgB, or a random access contention resolution window for monitoring msg4. The random access monitoring window circuit configuration 746 may be configured to select a selected monitoring window 720 for monitoring a particular random access message (e.g., msg2, msg4, or msgB), for example. The selected monitoring window may be selected from at least a first monitoring window and a second monitoring window, where the first monitoring window has a first duration that is different from a second duration of the second monitoring window.

[0085] In some examples, the random access monitoring window circuit configuration 746 may be configured to select the selected monitoring window 720 based on the RACH type among a plurality of RACH types. For example, each RACH type may be associated with a different respective UE type or data transmission type. In some examples, the first duration of the first monitoring window is less than the second duration of the second monitoring window. In this example, the random access monitoring window circuit configuration 746 may be configured to select the first monitoring window having a shorter duration when the current data transmission type to be utilized by the UE is a small data transmission type.

[0086] The random access monitoring window circuit configuration 746 can be further configured to initialize the timer 722 along with the time duration of the selected monitoring window 720. Different random access monitoring windows 720 can be selected for each of the random access monitoring window types (e.g., random access response window, random access msgB response window, and random access contention resolution window). Thus, the random access monitoring window circuit configuration 746 can initialize each respective timer 722 for the selected monitoring window 720 of each monitoring window type.

[0087] In some examples, the random access monitoring window circuit configuration 746 can initialize the timer 722 along with the selected monitoring window duration upon transmission of msg1 or msgA by the random access circuit configuration 744. In other examples, the random access monitoring window circuit configuration 746 can initialize the timer 722 along with the selected monitoring window duration at a start time offset by an offset time amount from the transmission time of msg1 or msgA. For example, the start time at which the timer 722 is initialized can be determined by adding the offset time amount to the transmission time of msg1 or msgA. In some examples, different offset time amounts can be configured for each of the random access response window, random access msgB response window, and random access contention resolution window.

[0088] In some examples, the selected monitoring window 720 can be a random access contention resolution window. In this example, the random access monitoring window circuit configuration 746 can be configured to update the selected monitoring window 720 (e.g., update the timer 722) upon receiving an indication of the selected monitoring window duration for the random access contention resolution window in msg2. The random access monitoring window circuit configuration 746 can be further configured to update the selected monitoring window 720 (e.g., update the timer 722) based on the uplink resources allocated for msg3 in msg2. The random access monitoring window circuit configuration 746 can be further configured to execute random access monitoring window instructions (software) 756 stored in the computer-readable medium 706 to implement one or more of the functions described herein.

[0089] FIG. 8 is a conceptual diagram illustrating an example of a hardware implementation for an exemplary base station 800 that employs a processing system 814. For example, the base station 800 can correspond to any one or more of the base stations (e.g., gNB) or other scheduling entities shown in any one or more of FIGS. 1, 2, 4, or 5.

[0090] According to various aspects of the present disclosure, an element, or any part of an element, or any combination of elements, may be implemented using a processing system 814 that includes one or more processors 804. The processing system 814 may be substantially the same as the processing system 714 shown in FIG. 7 and includes a bus interface 808, a bus 802, a memory 805, a processor 804, and a computer-readable medium 806. Further, the base station 800 may include any user interface 812 and transceiver 810 that are substantially similar to those described above in FIG. 7. In some examples, the transceiver 810 may include a phase shifter 816 for digital and / or analog beamforming via one or more antenna arrays 830. The processor 804 utilized in the base station 800 may be used to implement any one or more of the processes described below.

[0091] In some aspects of the present disclosure, the processor 804 may include circuitry configured for various functions. For example, the processor 804 may include a resource allocation and scheduling circuit configuration 842 configured to generate, schedule, and modify resource allocations or grants for time-frequency resources (e.g., a set of one or more resource elements). For example, the resource allocation and scheduling circuit configuration 842 may schedule time-frequency resources within a plurality of time-division duplex (TDD) and / or frequency-division duplex (FDD) subframes, slots, and / or minislots for carrying user data traffic and / or control information to and / or from a plurality of UEs.

[0092] In some examples, the resource allocation and scheduling circuit configuration 842 may be configured to schedule resources for the transmission of random access messages, such as msg1, msg2, msg3, and msg4, or msgA and msgB. The resource allocation and scheduling circuit configuration 842 may be further configured to reserve an unlicensed channel for channel occupancy time (COT) and to schedule resources for the transmission of random access messages within the COT. The resource allocation and scheduling circuit configuration 842 may be further configured to execute resource allocation and scheduling instructions (software) 852 stored in the computer-readable medium 806 to implement one or more of the functions described herein.

[0093] The processor 804 may further include a communication and processing circuit configuration 844 configured to communicate with the UE. In some examples, the communication and processing circuit configuration 844 may include one or more hardware components that provide a physical structure for performing processes related to wireless communication (e.g., signal reception and / or signal transmission) and signal processing (e.g., processing of received signals and / or processing of signals for transmission).

[0094] In some examples, the communication and processing circuit configuration 844 may be configured to transmit random access messages, such as msg2 or msg4 in a 4-step random access procedure, or msgB in a 2-step random access procedure. The communication and processing circuit configuration 844 may be further configured to receive random access messages, such as msg1 or msg3 in a 4-step random access procedure, or msgA in a 2-step random access procedure. The communication and processing circuit configuration 844 may be further configured to execute communication and processing instructions (software) 854 stored in the computer-readable medium 806 to implement one or more of the functions described herein.

[0095] Processor 804 may further include a random access circuit configuration 846 configured to perform a random access procedure, such as a two-step random access procedure or a four-step random access procedure, with the UE. In some examples, the random access circuit configuration 846 may be configured to receive a first random access message (e.g., msg1 or msgA) from the UE and, in response to msg1 or msgA, generate and transmit a random access response message (e.g., msg2 or msgB) to the UE. In a four-step random access procedure, the random access circuit configuration 846 may be further configured to receive an uplink message (e.g., msg3) from the UE in response to msg2 and, in response to msg3, transmit a contention resolution message (e.g., msg4) to the UE.

[0096] In some examples, the random access circuit configuration 846 may be further configured to select one or more random access monitoring windows 820 that will be utilized by the UE when monitoring random access messages from the base station 800. The random access monitoring window 820 may include one or more of a random access response window for monitoring msg2, a random access msgB response window for monitoring msgB, or a random access contention resolution window for monitoring msg4. The random access circuit configuration 846 may be configured to select a selected random access monitoring window 820 for monitoring a particular random access message (e.g., msg2, msg4, or msgB), for example. The selected random access monitoring window may be selected from at least a first monitoring window and a second monitoring window, where the first monitoring window has a first duration that is different from a second duration of the second monitoring window. In some examples, each of the monitoring window durations may be associated with a respective one of a plurality of RACH types. For example, each RACH type may be associated with a different respective UE type or data transmission type. In some examples, the first duration of the first monitoring window is less than the second duration of the second monitoring window. In this example, the random access circuit configuration 846 may be configured to select the first monitoring window having the shorter duration when the current data transmission type to be utilized by the UE is a small data transmission type.

[0097] In some examples, msg1 or msgA may include a PRACH preamble indicating a RACH type associated with the UE (e.g., a current RACH type associated with the current data transmission type utilized by the UE). The RACH type may further indicate a respective monitoring window duration for one or more random access monitoring windows on the UE. In this example, the random access circuitry 846 may select a respective selected monitoring window 820 for one or more monitoring window types (e.g., a random access response window, a random access msgB response window, and a random access contention resolution window) based on the PRACH preamble.

[0098] In some examples, msgA may utilize resources for a PUSCH indicating the RACH type. In some examples, the payload for the PUSCH of msgA may have a payload size indicating the RACH type and thus the monitoring window duration. For example, the payload size of the PUSCH of msgA may be smaller for a shorter monitoring window duration and larger for a longer monitoring window duration. In these examples, the random access circuitry 846 may select a respective selected monitoring window 820 for one or more monitoring window types (e.g., a random access response window, a random access msgB response window, and a random access contention resolution window) based on the resources utilized for the PUSCH of msgA or the payload size of the PUSCH of msgA.

[0099] The random access circuit configuration 846 may be further configured to include an indication of a selected monitoring window duration for the random access contention resolution window in msg2. For example, msg2 may include a time duration selected for the random access contention resolution window, or an index indicating the selected time duration. As another example, the uplink grant for msg3 included in msg2 may indicate a selected time duration. In other examples, the uplink grant may include a plurality of uplink grants each associated with a different time duration for the random access contention window. In this example, the random access circuit configuration 846 may be configured to select a selected monitoring window time duration for the random access contention resolution monitoring window based on the uplink resources utilized by the UE to transmit msg3. In other examples, the random access circuit configuration 846 may select a selected monitoring window time duration for the random access contention resolution message based on the payload size of msg3. For example, the payload size of msg3 may be smaller for a shorter monitoring window duration and larger for a longer monitoring window duration.

[0100] The random access circuit configuration 846 may be further configured to initialize timer 822 with each selected time duration for each selected monitoring window 820. The random access circuit configuration 846 may utilize timer 822 to operate with the resource allocation and scheduling circuit configuration 842 to schedule resources for the transmission of msg2, msgB, and / or msg4 within the selected monitoring window 820. The random access circuit configuration 846 may be further configured to execute random access instructions (software) 856 stored in the computer-readable medium 806 to implement one or more of the functions described herein.

[0101] Figure 9 is a flowchart illustrating an exemplary process 900 for selecting a random access monitoring window in a UE according to some embodiments. As described below, some or all of the features shown may be omitted in certain implementations within the scope of the present disclosure, and some of the features shown may not be required for implementation in all embodiments. In some examples, process 900 may be performed by UE 700 shown in FIG. 7. In some examples, process 900 may be performed by any suitable device or means for performing the functions or algorithms described below.

[0102] In block 902, the UE may transmit a first random access message to the base station during a random access procedure. In some examples, the UE may select a physical random access channel (PRACH) preamble for the first random access message based on the current RACH type among a plurality of RACH types associated with the current data transmission type among the plurality of data transmission types utilized by the UE. In some examples, the random access procedure is a two-step random access procedure, and the first random access message includes msgA in the two-step random access procedure. In this example, the UE may select at least one of a physical random access channel (PRACH) preamble of the first random access message or a resource for a physical uplink shared channel based on the current RACH type associated with the current data transmission type. For example, the random access circuitry 744 may provide means for transmitting a first random access message to the base station, together with the communication and processing circuitry 742 and the transceiver 710 illustrated and described above with respect to FIG. 7.

[0103] At 904, the UE may select a selected monitoring window from at least a first monitoring window and a second monitoring window. The first monitoring window has a first duration that is different from the second duration of the second monitoring window. In some examples, the selected monitoring window is within the channel occupancy time of the unauthorized channel.

[0104] In some examples, the UE may initialize a timer with the first duration or the second duration based on the selected monitoring window. In some examples, the UE may initialize the timer when transmitting the first random access message. In this example, each of the first duration and the second duration may be associated with a different respective RACH type, and each RACH type may be associated with a different respective data transmission type. In some examples, the first duration is less than the second duration, and the UE may select the first monitoring window as the selected monitoring window when the current data transmission type is a small data transmission type.

[0105] In some examples, the first duration is less than the second duration, and the selected monitoring window is the first monitoring window. In this example, the UE may initialize the timer at a start time offset by an offset time amount from the transmission time of the first random access message. In some examples, the second random access message is a random access response, and the selected monitoring window is a random access response window. For example, the random access procedure may include a two-step random access procedure, and the second random access message may include msgB in the two-step random access procedure. In this example, msgB includes a random access response and a contention resolution message in the two-step random access procedure, and the random access response window is a random access msgB response window.

[0106] In an example where the random access procedure is a two-step random access procedure and the first random access message is msgA of the two-step random access procedure, the UE may further select a monitoring window based on the payload size of msgA or the resources utilized for msgA.

[0107] In some examples, the first random access message includes a physical random access channel (PRACH) preamble and the second random access message includes a contention resolution message. In this example, the UE may further receive a third random access message including a random access response in response to the first random access message, and may transmit a fourth random access message including an uplink message for contention resolution in response to the random access response. In this example, the UE may select the selected monitoring window based on the payload size of the uplink message or the resources utilized for the uplink message. As another example, the UE may receive an indication of the selected monitoring window in the random access response. For example, the random access monitoring window circuit configuration 746 may provide means for selecting the selected monitoring window together with the random access circuit configuration 744 illustrated and described above with respect to FIG. 7.

[0108] At 906, the UE may monitor a second random access message from the base station within a selected monitoring window. In some examples, the first random access message includes a physical random access channel (PRACH) preamble, and the second random access message includes a contention resolution message. In this example, in response to the first random access message, the UE may further receive a third random access message including a random access response, and in response to the random access response, may transmit a fourth random access message including an uplink message for contention resolution. In this example, the UE may monitor the second random access message in response to the uplink message, where the selected monitoring window is a random access contention resolution window. For example, the random access circuit configuration 744 illustrated and described above with respect to FIG. 7 may monitor a second random access message from the base station within a selected monitoring window.

[0109] In one configuration, the UE 700 includes various means as described in this disclosure. In one aspect, the means described above may be the processor 704 shown in FIG. 7 configured to perform the functions enumerated by the means described above. In another aspect, the means described above may be a circuit or any device configured to perform the functions enumerated by the means described above.

[0110] Of course, in the above example, the circuit configuration included in the processor 704 is provided by way of example only, and other means for performing the described functions include, but are not limited to, instructions stored in the computer-readable medium 706, or any other suitable device or means that utilizes the processes and / or algorithms described in any one of FIGS. 1, 2, and / or 4 - 6 and described herein with respect to, for example, FIG. 9, and may be included within various aspects of the present disclosure.

[0111] FIG. 10 is a flowchart illustrating an exemplary process 1000 for selecting a random access monitoring window at a base station according to some embodiments. As will be described below, some or all of the features shown may be omitted in certain implementations within the scope of the present disclosure, and some of the features shown may not be required for implementation of all embodiments. In some examples, process 1000 may be performed by base station 800 shown in FIG. 8. In some examples, process 1000 may be performed by any suitable device or means for performing the functions or algorithms described below.

[0112] At block 1002, the base station may receive a first random access message from a user equipment (UE) during a random access procedure. For example, the random access circuitry 846 may provide means for receiving the first random access message, together with the communication and processing circuitry 844 and the transceiver 810 illustrated and described above with respect to FIG. 8.

[0113] At block 1004, the base station may select a selected monitoring window from at least a first monitoring window and a second monitoring window for transmitting a second random access message therein. The first monitoring window has a first duration that is different from a second duration of the second monitoring window. In some examples, the selected monitoring window is within the channel occupancy time of the unlicensed channel. In some examples, the base station may initialize a timer, together with the first duration or the second duration, based on the selected monitoring window.

[0114] In some examples, the first time duration is less than the second time duration, and the selected monitoring window is the first monitoring window. In this example, the second random access message can be a random access response, and the selected monitoring window can be a random access response window. As an example, the random access procedure can include a two-step random access procedure, and the second random access message can include msgB in the two-step random access procedure. In this example, msgB includes a random access response and a contention resolution message in the two-step random access procedure, and the random access response window is a random access msgB response window.

[0115] In some examples, each of the first time duration and the second time duration is associated with a different respective random access channel (RACH) type among a plurality of RACH types. In some examples, the plurality of RACH types are each associated with a different respective data transmission type among a plurality of data transmission types. In some examples, the base station can select the selected monitoring window based on the physical random access channel (PRACH) preamble of the first random access message. The PRACH preamble can indicate the current RACH type among the plurality of RACH types associated with the current data transmission type among the plurality of data transmission types used by the UE.

[0116] In some examples, the random access procedure is a two-step random access procedure, and the first random access message includes msgA in the two-step random access procedure. In this example, the base station can select the selected monitoring window based on at least one of the physical random access channel (PRACH) preamble of the first random access message, which indicates the current RACH type among the plurality of RACH types associated with the current data transmission type among the plurality of data transmission types used by the UE, or the resources for the physical uplink shared channel.

[0117] In some examples, the first random access message includes a physical random access channel (PRACH) preamble, and the second random access message includes a contention resolution message. In this example, the base station may further transmit a third random access message with a random access response in response to the first random access message, and may receive a fourth random access message with an uplink message for contention resolution in response to the random access response. In this example, the base station may select a selected monitoring window based on the payload size of the uplink message or the resources utilized for the uplink message. In an example where the random access procedure is a two-step random access procedure, the base station may select a selected monitoring window based on the payload size of msgA or the resources utilized for msgA.

[0118] In an example where the random access procedure is a four-step random access procedure, the base station may include an indication of the selected monitoring window within the random access response. For example, the random access circuit configuration 846 illustrated and described above with respect to FIG. 8 may provide means for selecting a selected monitoring window.

[0119] At 1006, the base station may transmit a second random access message to the UE within the selected monitoring window. In some examples, the first random access message includes a physical random access channel (PRACH) preamble, and the second random access message includes a contention resolution message. In this example, the base station further transmits a third random access message including a random access response in response to the first random access message, and may receive a fourth random access message including an uplink message for contention resolution in response to the random access response. The base station may then transmit a second random access response in response to the uplink message. In this example, the selected monitoring window may include a random access contention resolution window. For example, the random access circuit configuration 846 may provide means for transmitting a second random access message to the UE, together with the communication and processing circuit configuration 844 illustrated and described above with respect to FIG. 8.

[0120] In one configuration, the base station 800 includes various means as described in this disclosure. In one aspect, the means described above may be the processor 804 shown in FIG. 8 configured to perform the functions enumerated by the means described above. In another aspect, the means described above may be a circuit or any device configured to perform the functions enumerated by the means described above.

[0121] Of course, in the above example, the circuit configuration included in the processor 804 is provided by way of example only, and other means for performing the described functions include, but are not limited to, instructions stored in the computer-readable medium 806, or any other suitable device or means that utilizes the processes and / or algorithms described in any one of FIGS. 1, 2, and / or 4 - 6 and, for example, described herein with respect to FIG. 10, and may be included within various aspects of this disclosure.

[0122] Additional information regarding various aspects of the present disclosure and some exemplary embodiments of the present invention is provided in the accompanying appendix filed herewith.

[0123] Some aspects of wireless communication networks have been presented with reference to exemplary implementations. As will be readily appreciated by those skilled in the art, the various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures, and communication standards.

[0124] By way of example, the various aspects may be implemented within other systems defined by the 3rd Generation Partnership Project (3GPP®), such as Long Term Evolution (LTE), Evolved Packet System (EPS), Universal Mobile Telecommunications System (UMTS), and / or Global System for Mobile (GSM). The various aspects may also be extended to systems defined by the 3rd Generation Partnership Project 2 (3GPP2), such as CDMA2000 and / or Evolution-Data Optimized (EV-DO). Other examples may be implemented within systems employing IEEE802.11 (Wi-Fi), IEEE802.16 (WiMAX), IEEE802.20, Ultra Wide Band (UWB), systems employing Bluetooth, and / or other suitable systems. The actual telecommunication standards, network architectures, and / or communication standards employed will depend on the overall design constraints imposed on a particular application and system.

[0125] Within this disclosure, the term "exemplary" is used to mean "serving as an example, instance, or illustration." Any implementation or aspect described herein as "exemplary" should not necessarily be construed as being more preferred or advantageous than other aspects of the disclosure. Similarly, the term "aspect" does not require that all aspects of the disclosure include the discussed feature, advantage, or mode of operation. The term "coupled" is used herein to refer to either a direct or an indirect connection between two objects. For example, if object A physically contacts object B and object B contacts object C, objects A and C can still be considered to be coupled to each other even if they do not directly physically contact each other. For example, a first object can be coupled to a second object even if the first object is not in direct physical contact with the second object. The terms "circuit" and "circuitry" are used broadly and are not limited with respect to the type of electronic circuit, but include both the hardware implementation of an electrical device and conductors that, when connected and configured, enable the performance of the functions described in this disclosure, as well as the software implementation of information and instructions that, when executed by a processor, enable the performance of the functions described in this disclosure.

[0126] One or more of the components, steps, features, and / or functions shown in FIGS. 1-10 may be rearranged and / or combined into a single component, step, feature, or function, or embodied in some of the components, steps, or functions. Also, additional elements, components, steps, and / or functions may be added without departing from the novel features disclosed herein. The apparatus, device, and / or components shown in FIGS. 1, 2, and 4-8 may be configured to perform one or more of the methods, features, or steps described herein. Also, the novel algorithms described herein may be efficiently implemented in software and / or incorporated into hardware.

[0127] The specific order or hierarchy of steps in the disclosed method should be understood as illustrative of an exemplary process. It is understood that, based on design preferences, the specific order or hierarchy of steps in a method can be rearranged. The appended method claims present the elements of various steps in an exemplary order and are not meant to be limited to the specific order or hierarchy presented, unless otherwise specifically recited therein.

[0128] The foregoing 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 readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein but are to be accorded the widest scope consistent with the language of the claims, and the recitation of an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more." Unless otherwise specifically stated, the term "some" refers to one or more. The phrase referring to an enumeration "at least one of" refers to any combination of those items including a single member. By way of example, "at least one of a, b, or c" is intended to include a, b, c, a and b, a and c, b and c, as well as a, b, and c. All structural and functional equivalents to the various elements of the aspects described throughout this disclosure that are known or later come to be known to those skilled in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is to be dedicated to the public regardless of whether such disclosure is expressly recited in the claims. An element of a claim is not to be construed under the provisions of 35 U.S.C. § 112, paragraph (f) unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is expressly recited using the phrase "step for."

Description of Reference Signs

[0129] 100 Wireless communication system 102 Core network 104 Radio Access Network (RAN), RAN, Radio Access Network 106 User Equipment (UE), UE, Scheduled Entity, UE / Scheduled Entity 108 Base station, Scheduling Entity, Base station / Scheduling Entity 110 External data network 112 Downlink traffic 114 Downlink control information 116 Uplink traffic 120 Backhaul portion, Backhaul 200 RAN, Radio Access Network, Network 202 Macrocell, Cell, Serving cell 204 Macrocell, Cell 206 Macrocell, Cell, Neighbor cell 208 Small cell, Cell 210 Base station, Serving base station 212, 218, 402, 800 Base station 214 Third base station, Base station 216 Remote Radio Head (RRH), RRH, Base station 220 Unmanned Aerial Vehicle (UAV), UAV 222, 224, 226, 228, 230, 232, 234, 238, 240, 242, 404, 504 UE 227 Sidelink signal, Sidelink signaling, Sidelink 237 Peer-to-peer (P2P) or Sidelink signal, Sidelink signal, Sidelink signaling, Sidelink 302 Exemplary DL subframe, Subframe, 1ms subframe 304 Resource grid 306 Resource Element (RE), Resource Element, RE 308 Resource Block (RB), RB 310 Slot 312 Control Region 314 Data Region 400 4-Step Contention-Based Random Access (CBRA) Procedure, Random Access Procedure, 4-Step CBRA Procedure, Contention-Based Random Access Procedure, 4-Step Random Access Procedure 406 RACH Preamble Message, msg1 408 Random Access Response (RAR) Message, msg2(RAR), msg2, RAR Message, Random Access Response 410 Uplink Message (msg3), Uplink Message 412 Contention Resolution Message 500 2-Step Random Access Procedure 502 gNB 506 msgA 508 msgB 602 4-Step Random Access Procedure, Random Access Procedure 604 2-Step Random Access Procedure, Random Access Procedure 606 Random Access Response Window, Window 608 Random Access Contention Resolution Window, Window 610 Random Access msgB Response Window, Window 700 User Equipment (UE), UE 702, 802 Bus 704, 804 Processor 705, 805 Memory 706, 806 Computer Readable Medium 708, 808 Bus Interface 710, 810 Transceiver 712, 812 User Interface 714, 814 Processing System 720 Random Access Monitoring Window, Selected Monitoring Window 722, 822 Timer 730, 830 Antenna Array 742, 844 Communication and Processing Circuit Configuration 744 and 846 Random Access Circuit Configuration 746 Random Access Monitoring Window Circuit Configuration 752 Communication and Processing Instructions (Software) 754 Random Access Instructions (Software) 756 Random Access Monitoring Window Instructions (Software) 816 Phase Shifter 820 Random Access Monitoring Window, Selected Random Access Monitoring Window, Selected Monitoring Window 842 Resource Allocation and Scheduling Circuit Configuration 852 Resource Allocation and Scheduling Instructions (Software) 854 Communication and Processing Instructions (Software) 856 Random Access Instructions (Software)

Claims

1. A method of wireless communication in a user equipment (UE), comprising: During a random access procedure, transmitting a first random access message to a base station; Selecting a selected monitoring window from at least a first monitoring window and a second monitoring window, wherein the first monitoring window has a first duration different from a second duration of the second monitoring window; Monitoring, within the selected monitoring window, a second random access message from the base station; The method further comprising: The first random access message comprises a physical random access channel (PRACH) preamble, the second random access message comprises a contention resolution message, and the method further comprises: Receiving, in response to the first random access message, a third random access message comprising a random access response; Transmitting, in response to the random access response, a fourth random access message comprising an uplink message for contention resolution; The method further comprising: Receiving an indication of the selected monitoring window in the random access response; A method.

2. Initializing a timer based on the selected monitoring window, together with the first duration or the second duration; The method according to claim 1, further comprising the above step.

3. A transceiver; A memory; A processor coupled to the transceiver and the memory, the processor being configured to: During a random access procedure, transmit a first random access message to a base station; Select a selected monitoring window from at least a first monitoring window and a second monitoring window, wherein the first monitoring window has a first duration different from a second duration of the second monitoring window; Monitor, within the selected monitoring window, a second random access message from the base station; And configured to perform the above operations. The first random access message comprises a physical random access channel (PRACH) preamble, the second random access message comprises a contention resolution message, and the processor receives a third random access message comprising a random access response in response to the first random access message; transmits a fourth random access message comprising an uplink message for contention resolution in response to the random access response; further includes, and selecting the selected monitoring window is receiving an indication of the selected monitoring window in the random access response A user equipment (UE) configured to further perform the above. **Claim 4** The processor is further configured to initialize a timer together with the first time duration or the second time duration based on the selected monitoring window. The UE according to claim 3, configured to further perform the above. **Claim 5** The UE according to claim 4, wherein the first time duration is less than the second time duration, and the selected monitoring window comprises the first monitoring window. **Claim 6** The processor is further configured to initialize the timer at a start time offset by an offset time amount from the transmission time of the first random access message. The UE according to claim 5, configured to further perform the above. **Claim 7** The UE according to claim 6, wherein the second random access message comprises a random access response, and the selected monitoring window comprises a random access response window. **Claim 8** The random access procedure comprises a two-step random access procedure, the second random access message comprises msgB in the two-step random access procedure, and msgB comprises the random access response and the contention resolution message in the two-step random access procedure. The UE according to claim 7, wherein the random access response window comprises a random access msgB response window. **Claim 9** The first random access message comprises a physical random access channel (PRACH) preamble, the second random access message comprises a contention resolution message, and the processor Receiving, in response to the first random access message, a third random access message comprising a random access response Transmitting, in response to the random access response, a fourth random access message comprising an uplink message for contention resolution configured to further perform, and monitoring the second random access message monitoring the second random access message in response to the uplink message, wherein the selected monitoring window comprises a random access contention resolution window The UE according to claim 6, further comprising

10. The processor Initializing the timer upon transmission of the first random access message, wherein each of the first duration and the second duration is associated with a different respective RACH type among a plurality of random access channel (RACH) types The UE according to claim 4, configured to further perform

11. The UE according to claim 10, wherein the plurality of RACH types are each associated with a different respective data transmission type among a plurality of data transmission types

12. The first duration is less than the second duration, and the processor selecting the first monitoring window as the selected monitoring window when the current data transmission type among the plurality of data transmission types used by the UE comprises a small data transmission type The UE according to claim 11, configured to further perform

13. The processor selecting a physical random access channel (PRACH) preamble for the first random access message based on the current RACH type among the plurality of RACH types associated with the current data transmission type used by the UE The UE according to claim 11, configured to further perform

14. The random access procedure comprises a two-step random access procedure, the first random access message comprises msgA in the two-step random access procedure, and the processor Selecting at least one of a physical random access channel (PRACH) preamble of the first random access message or a resource for a physical uplink shared channel based on a current RACH type among the plurality of RACH types associated with a current data transmission type among the plurality of data transmission types used by the UE The UE according to claim 11, further configured to perform the above.

15. The UE according to claim 3, wherein the selected monitoring window is within a channel occupancy time of an unauthorized channel.

16. A memory, A processor coupled to the memory, the processor Receiving, from a user equipment (UE), a first random access message during a random access procedure; Selecting a selected monitoring window from at least a first monitoring window and a second monitoring window, the first monitoring window having a first duration different from a second duration of the second monitoring window; Transmitting a second random access message to the UE within the selected monitoring window Configured to perform, The first random access message includes a physical random access channel (PRACH) preamble, the second random access message includes a contention resolution message, and the processor Transmitting a third random access message including a random access response in response to the first random access message, the random access response including an indication of the selected monitoring window; Receiving a fourth random access message including an uplink message for contention resolution in response to the random access response The network element is further configured to perform the above.

17. The processor Initializing a timer together with the first duration or the second duration based on the selected monitoring window The network element according to claim 16, further configured to perform the above.

18. The first time duration is less than the second time duration, and the selected monitoring window comprises the first monitoring window, the network element according to claim 17.

19. The second random access message comprises a random access response, and the selected monitoring window comprises a random access response window, the network element according to claim 18.

20. The first random access message comprises a physical random access channel (PRACH) preamble, the second random access message comprises a contention resolution message, and the processor transmits a third random access message comprising a random access response in response to the first random access message; receives a fourth random access message comprising an uplink message for contention resolution in response to the random access response; and transmits the second random access message in response to the uplink message, wherein the selected monitoring window comprises a random access contention resolution window. The network element according to claim 17, further configured to perform the foregoing.

21. Each of the first time duration and the second time duration is associated with a different respective RACH type among a plurality of random access channel (RACH) types, wherein the plurality of RACH types are each associated with a different respective data transmission type among a plurality of data transmission types, the network element according to claim 16.

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