Repetition and Pre - emphasis of Sidelink Signals

Abstract

To provide sidelink signal repetition and preemption.SOLUTION: A first wireless device receives from a second wireless device, indication of: one or more first resources of a sidelink transport block; and priority of the sidelink transport block. Based on the priority and a priority threshold, a sidelink transmission of one or more second resources that overlap with the one or more first resources is dropped. In one embodiment, the indication is indicated by sidelink control information. In one embodiment, the sidelink control information is received via a physical sidelink control channel (PSCCH).SELECTED DRAWING: Figure 43

Description

Background Art

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 910,359, filed Oct. 3, 2019, which is hereby incorporated by reference in its entirety.

Summary of the Invention

Means for Solving the Problems

[0002] In the present disclosure, various embodiments are presented as examples of how the disclosed technology can be implemented and / or how the disclosed technology can be practiced in environments and scenarios. It will be apparent to those skilled in the relevant art that various changes in form and detail can be made without departing from the scope. Indeed, after reading the specification, methods for implementing alternative embodiments will be apparent to those skilled in the relevant art. The present embodiments should not be limited by any of the exemplary embodiments. Embodiments of the present disclosure are described with reference to the accompanying drawings. Limitations, features, and / or elements from the disclosed exemplary embodiments can be combined to create further embodiments within the scope of the present disclosure. Figures highlighting functions and advantages are shown by way of example only. The disclosed architecture is sufficiently flexible and configurable so that it can be utilized in ways other than those shown. For example, any action listed in any flowchart can be rearranged or used as an optional only in some embodiments. The present invention provides, for example, the following. (Item 1) Receiving, by a first wireless device, from a base station, a message indicating a priority threshold for pre - emption of sidelink transmission; From a second wireless device, one or more first resources of a sidelink transport block, and receiving sidelink control information indicating the priority of the sidelink transport block; To determine that between the one or more first resources of the sidelink transport block and one or more second resources of one or more sidelink transmissions of the first wireless device, to determine that there is resource duplication; based on the priority and the priority threshold, to drop a first portion of the one or more sidelink transmissions that overlap with the one or more first resources; to transmit a second portion of the one or more sidelink transmissions, the method comprising. (Item 2) For a first wireless device, to receive from a base station a message indicating a priority threshold for preemption of sidelink transmissions; from a second wireless device, one or more first resources of a sidelink transport block, and to receive sidelink control information indicating the priority of the sidelink transport block; the one or more first resources of the sidelink transport block, and to determine that between the one or more first resources of the sidelink transport block and one or more second resources of one or more sidelink transmissions of the first wireless device, there is resource duplication; based on the priority and the priority threshold, to drop a first portion of the one or more sidelink transmissions that overlap with the one or more first resources, the method comprising. (Item 3) The method according to item 2, wherein the first portion includes the one or more second resources that completely or partially overlap with the one or more first resources. (Item 4) For a first wireless device, to receive from a base station a message indicating a priority threshold for preemption of sidelink transmissions; From a second wireless device, one or more first resources of a sidelink transport block, and receiving sidelink control information indicating the priority of the sidelink transport block; determining that one or more third resources are duplicate resources between the one or more first resources and one or more second resources for the sidelink transmission of the first wireless device; dropping the sidelink transmission of the one or more third resources based on the priority and a priority threshold. A method comprising. (Item 5) By a first wireless device, from a second wireless device, one or more first resources of a sidelink transport block, and receiving an indication of the priority of the sidelink transport block; dropping the sidelink transmission of one or more second resources that overlap with the one or more first resources based on the priority and a priority threshold. A method comprising. (Item 6) The method according to item 5, wherein the indication is indicated by sidelink control information. (Item 7) The method according to item 6, wherein the sidelink control information is received via a physical sidelink control channel (PSCCH). (Item 8) The method according to any one of items 5 to 7, wherein dropping the sidelink transmission of the one or more second resources further comprises dropping the sidelink transmission of one or more third resources. (Item 9) The method according to item 8, wherein the one or more third resources include the one or more second resources that completely or partially overlap with the one or more first resources. (Item 10) The method according to any one of Items 8 to 9, wherein the one or more third resources include one or more sub-channels in a sidelink resource pool. (Item 11) The method according to any one of Items 5 to 10, wherein the priority threshold is indicated by a base station. (Item 12) The method according to Item 11, wherein the first wireless device receives a message indicating the priority threshold from the base station. (Item 13) The method according to Item 12, wherein the message is received via a radio resource control message. (Item 14) The method according to any one of Items 12 to 13, wherein the message is received via a system information block. (Item 15) The method according to any one of Items 5 to 14, wherein the priority threshold is preconfigured. (Item 16) The method according to any one of Items 5 to 15, wherein the value of the priority is smaller than the priority threshold. (Item 17) The method according to any one of Items 5 to 16, further comprising transmitting, by the first wireless device, a first transport block via one or more fourth resources, wherein the one or more fourth resources are non-overlapping resources of the one or more first resources of the one or more second resources. (Item 18) The method according to Item 17, wherein the one or more fourth resources include one or more sub-channels in a sidelink resource pool. (Item 19) The method according to any one of Items 5 to 18, wherein the priority threshold is for preemption of the sidelink transmission. (Item 20) From a second wireless device, the one or more first resources, and The method according to any one of items 5 to 19, further comprising receiving sidelink control information indicating the priority. (Item 21) The method according to item 20, wherein the sidelink control information is received via a physical layer sidelink control channel. (Item 22) The method according to any one of items 5 to 21, further comprising receiving, by a first wireless device, from a base station, a message indicating the priority threshold. (Item 23) The method according to item 22, wherein the message is a radio resource control message. (Item 24) The method according to item 23, wherein the message is a system information block. (Item 25) The method according to any one of items 5 to 24, wherein the sidelink transmission is transmitted via one or more physical layer shared channels. (Item 26) The method according to any one of items 5 to 25, wherein the priority is less than the priority threshold. (Item 27) The method according to any one of items 5 to 26, wherein the one or more first resources include one or more subchannels within a sidelink resource pool. (Item 28) The method according to any one of items 5 to 27, wherein the one or more second resources include one or more subchannels within a sidelink resource pool. (Item 29) By a first wireless device, from a base station, Repeating a first number of sidelink synchronization signal blocks (SL-SSBs) within a synchronization signal periodicity, and Receiving one or more configuration messages indicating a timing gap between adjacent transmissions of clusters of the SL-SSB repetitions of the SL-SSB repetitions, Transmitting, to one or more second wireless devices, the cluster having the timing gap between adjacent transmissions of each of the clusters during the synchronization signal periodicity, wherein the cluster includes a repetition of a first number of sidelink synchronization signal blocks (SL-SSBs), and each of the clusters includes a repetition of a second number of consecutive SL-SSBs, the transmitting; a method including the above. (Item 30) By a first wireless device Receiving a display of a repetition of a first number of sidelink synchronization signal blocks (SL-SSBs) within a synchronization signal periodicity, and Receiving a display of the timing gap between adjacent transmissions of a cluster of repetitions of the SL-SSBs of the repetition of the SL-SSBs; a method including the above. Transmitting, during the synchronization signal periodicity, the cluster having the timing gap between adjacent transmissions of each of the clusters, wherein the cluster includes a repetition of the first number of SL-SSBs, and each of the clusters includes a repetition of a second number of consecutive SL-SSBs, the transmitting; a method including the above. (Item 31) The method according to item 30, wherein one or more configuration messages include the display. (Item 32) The method according to item 31, wherein the one or more configuration messages are RRC. (Item 33) The method according to any one of items 31 to 32, wherein the one or more configuration messages are SIB. (Item 34) The method according to any one of items 31 to 33, wherein the one or more configuration messages are RRC. (Item 35) The method according to any one of items 31 to 34, wherein the one or more configuration messages are SIB. (Item 36) Transmitting, by a first wireless device, the cluster having a timing gap between each adjacent transmission of the cluster during a synchronization signal periodicity, wherein the cluster includes a repetition of a first number of sidelink synchronization signal blocks (SL-SSBs), and each of the clusters includes a repetition of a second number of consecutive SL-SSBs, a method. (Item 37) The method according to item 36, wherein the timing gap and the first number are indicated by a message. (Item 38) The method according to item 37, wherein the message is received from a base station. (Item 39) The method according to any one of items 37 to 38, wherein the message is an RRC message. (Item 40) The method according to any one of items 37 to 39, wherein the message is an SIB. (Item 41) The method according to any one of items 37 to 40, wherein the second number is indicated by a message. (Item 42) The method according to item 41, wherein the message is received from a base station. (Item 43) The method according to any one of items 41 to 42, wherein the message is an RRC message. (Item 44) The method according to any one of items 41 to 43, wherein the message is an SIB. (Item 45) The method according to any one of items 36 to 44, wherein the timing gap is zero or more. (Item 46) The method according to any one of items 36 to 45, further comprising receiving, by the first wireless device, one or more configuration messages including an SL-SSB offset. (Item 47) The method according to item 46, further comprising that the repetition of the first SL-SSB of the repetition of the SL-SSBs starts from the SL-SSB offset. (Item 48) The method according to item 47, further comprising receiving, by the first wireless device, one or more configuration messages including an LTE sidelink synchronization signal (SLSS) offset. (Item 49) The method according to item 48, wherein the SL-SSB offset indicates the same time as the LTE SLSS offset. (Item 50) The method according to any one of items 36 to 49, wherein the second number is determined based on the first number and a subcarrier spacing (SCS). (Item 51) The method according to item 50, wherein the SCS is indicated by a base station. (Item 52) The method according to any one of items 50 to 51, wherein the SCS is preconfigured. (Item 53) The method according to any one of items 50 to 52, wherein the SCS is indicated for a sidelink bandwidth part. one item described above. (Item 54) The method according to any one of items 36 to 53, wherein the transmitting further includes transmitting to one or more second wireless devices. (Item 55) The SL-SSB is a primary sidelink synchronization signal, a secondary sidelink synchronization signal, and a physical sidelink broadcast channel, and the method according to any one of items 36 to 54. (Item 56) The method according to any one of items 36 to 55, wherein the second number is determined based on a subcarrier spacing (SCS) of the SL-SSB. (Item 57) The second number is 1 for 15 kHz SCS, 2 for 30 kHz SCS, 4 for 60 kHz SCS, 8 for 120 kHz SCS, and 16 for 240 kHz SCS, the method according to item 56, which is one of them. (Item 58) A first wireless device, One or more processors, A memory that stores instructions for causing the first wireless device to perform the method according to any one of items 1 to 57 when executed by the one or more processors, a first wireless device. (Item 59) A non-transitory computer-readable medium that includes instructions for causing the one or more processors to perform the method according to any one of items 1 to 57 when executed by the one or more processors. (Item 60) A first wireless device, One or more first processors, When executed by the one or more first processors, the first wireless device One or more first resources of a sidelink transport block, and A first memory that stores first instructions for causing the first wireless device to transmit a display of the priority of the sidelink transport block, a first wireless device, and A second wireless device, One or more second processors, When executed by the one or more second processors, the second wireless device Receiving the display, and A second memory that stores second instructions for causing the second wireless device to drop a sidelink transmission of one or more second resources that overlap with the one or more first resources based on the priority and a priority threshold, a second wireless device, and a system.

Brief Description of the Drawings

[0003] Examples of some of the various embodiments of the present disclosure are described herein with reference to the drawings.

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Mode for Carrying Out the Invention

[0052] Embodiments can be configured to operate as needed. The disclosed mechanisms can be executed, for example, in a wireless device, a base station, a wireless environment, a network, the above combinations, etc., when certain criteria are met. Exemplary criteria may be based at least in part on, for example, wireless device or network node configuration, traffic load, initial system settings, packet size, traffic characteristics, the above combinations, etc. When one or more criteria are met, various exemplary embodiments can be applied. Thus, it may be possible to implement exemplary embodiments that selectively implement the disclosed protocol.

[0053] The base station can communicate with a mixture of wireless devices. The wireless device and / or the base station can support multiple technologies and / or multiple releases of the same technology. The wireless device can have some specific capabilities depending on the category and / or capabilities of the wireless device. When the present disclosure refers to a base station communicating with multiple wireless devices, the present disclosure can refer to a subset of all wireless devices within the coverage area. The present disclosure can refer to, for example, multiple wireless devices of a given LTE or 5G release that include a given capability and are in a given sector of the base station. The multiple wireless devices in the present disclosure can refer to a selected multiple wireless devices and / or a subset of all wireless devices within the coverage area that are executed according to the disclosed method, etc. There may be multiple base stations or multiple wireless devices in a coverage area that do not conform to the disclosed method. For example, those wireless devices or base stations are executed based on an older release of LTE or 5G technology.

[0054] As used herein, the terms "a" and "an" and similar phrases are to be construed as "at least one" and "one or more". Similarly, any term ending with the suffix "(s)" should be construed as "at least one" and "one or more". As used herein, the term "may" is to be construed as "for example, can be". In other words, the term "may" indicates that the phrase following the term "may" is one example of a plurality of appropriate possibilities and may or may not be used by one or more of the various embodiments. As used herein, the terms "comprises" and "consists of" enumerate one or more components of the recited element. The term "comprises" is interchangeable with "includes" and does not exclude unrecited components included in the recited element. In contrast, "consists of" provides a complete enumeration of one or more components of the recited element. As used herein, the term "based on" should be construed as "at least partially based on" rather than, for example, "based only on". As used herein, the term "and / or" represents any possible combination of the recited elements. For example, "A, B, and / or C" can represent A, B, C, A and B, A and C, B and C, or A, B, and C.

[0055] If A and B are sets and all elements of A are also elements of B, then A is called a subset of B. In this specification, only non-empty sets and subsets are considered. For example, the possible subsets of B = {Cell 1, Cell 2} are {Cell 1}, {Cell 2}, and {Cell 1, Cell 2}. The phrase "based on" (or equivalently "at least based on") indicates an example of one of a number of suitable possibilities where the phrase following "based on" may or may not be used in one or more of various embodiments. The phrase "in response to" (or equivalently "at least in response to") indicates an example of one of a number of suitable possibilities where the phrase following "in response to" may or may not be used in one or more of various embodiments. The phrase "in accordance with" (or equivalently "at least in accordance with") indicates an example of one of a number of suitable possibilities where the phrase following "in accordance with" may or may not be used in one or more of various embodiments. The phrase "employ / use" (or equivalently "at least employ / use") indicates an example of one of a number of appropriate possibilities where the phrase following "employ / use" may or may not be used in one or more of various embodiments.

[0056] The term "comprising" can relate to the capacity of a device, whether the device is in an operating state or a non-operating state. "Comprising" can also refer to specific settings of a device that affect the operating characteristics of the device, whether the device is in an operating state or a non-operating state. In other words, hardware, software, firmware, registers, memory values, etc. can be "configured" within a device whether the device is in an operating state or a non-operating state in order for the device to provide certain characteristics. Terms such as "control messages generated in a device" can mean that, whether the device is in an operating state or a non-operating state, the control messages can be used to configure certain characteristics in the device or can have parameters that can be used to implement certain actions in the device.

[0057] In the present disclosure, a parameter (or equivalently a field, or information element: called an IE) can include one or more information objects, and an information object can include one or more other objects. For example, if parameter (IE) N includes parameter (IE) M, parameter (IE) M includes parameter (IE) K, and parameter (IE) K includes parameter (information element) J, then for example, N includes K and N includes J. In an exemplary embodiment, when one or more messages include a plurality of parameters, it means that among the plurality of parameters, the parameters are included in at least one of the one or more messages, but do not have to be included in each of the one or more messages.

[0058] Furthermore, many of the features presented above are described as being optional, either by the use of "may" or the use of parentheses. For the sake of brevity and readability, the present disclosure does not explicitly describe every possible variation that could be obtained by selecting from the set of optional features. The present disclosure should be construed as disclosing all such variations explicitly. For example, a system described as having three optional features could be implemented in seven ways, namely, by only one of the three possible features, by any two of the three features, or by all three of the three features.

[0059] Many of the elements described in the disclosed embodiments can be implemented as modules. Here, a module is defined as an element that performs a defined function and has a defined interface to other elements. The modules described in the present disclosure may be implemented in hardware, software combined with hardware, firmware, wetware (e.g., hardware having biological elements), or combinations thereof, and they can be behaviorally equivalent. For example, a module can be implemented as a software routine described in a computer language configured to be executed on a hardware machine (such as C, C++, Fortran, Java®, Basic, Matlab®) or in Simulink, Stateflow, GNU Octave, or LabVIEW MathScript. It may also be possible to implement a module using physical hardware incorporating discrete or programmable analog, digital, and / or quantum hardware. Examples of programmable hardware include computers, microcontrollers, microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs). Computers, microcontrollers, and microprocessors are programmed using languages such as assembly, C, C++. FPGAs, ASICs, and CPLDs are often programmed using hardware description languages (HDLs) such as VHSIC Hardware Description Language (VHDL) or Verilog, which configure connections between internal hardware modules with fewer programmable device functions. To achieve the results of functional modules, the above techniques are often used in combination.

[0060] Figure 1A shows an example of a mobile communication network 100 in which embodiments of the present disclosure may be implemented. The mobile communication network 100 may be, for example, a public land mobile network (PLMN) operated by a network operator. As shown in Figure 1A, the mobile communication network 100 includes a core network (CN) 102, a radio access network (RAN) 104, and a wireless device 106.

[0061] CN 102 may provide an interface to one or more data networks (DNs) such as a public DN (e.g., the Internet), a private DN, and / or an operator-internal DN to the wireless device 106. As part of the interface function, CN 102 may set up an end-to-end connection between the wireless device 106 and one or more DNs, authenticate the wireless device 106, and provide a charging function.

[0062] RAN 104 may connect CN 102 to the wireless device 106 via wireless communication on an air interface. As part of the wireless communication, RAN 104 may provide scheduling, radio resource management, and a retransmission protocol. The communication direction from RAN 104 to the wireless device 106 on the air interface is known as the downlink, and the communication direction from the wireless device 106 to RAN 104 on the air interface is known as the uplink. Downlink transmission may be separated from uplink transmission using frequency division duplexing (FDD), time division duplexing (TDD), and / or some combination of the two duplexing techniques.

[0063] The term "wireless device" is used throughout this disclosure to refer to and encompass any mobile or fixed (non-portable) device for which wireless communication is necessary or available. For example, a wireless device can be a phone, smartphone, tablet, computer, laptop, sensor, meter, wearable device, Internet of Things (IoT) device, vehicle roadside unit (RSU), relay node, automobile, and / or any combination thereof. The term "wireless device" encompasses other terms including user equipment (UE), user terminal (UT), access terminal (AT), mobile station, handset, wireless transmit / receive unit (WTRU), and / or wireless communication device.

[0064] RAN104 may include one or more base stations (not shown). The term "base station" can be used throughout this disclosure to refer to and encompass Node B (associated with UMTS and / or 3G standards), evolved Node B (eNB, associated with E-UTRA and / or 4G standards), remote radio head (RRH), a baseband processing unit coupled to one or more RRHs, a repeater node or relay node used to extend the coverage area of a donor node, next-generation evolved Node B (ng-eNB), gNode B (gNB, associated with NR and / or 5G standards), access point (AP, e.g., associated with WiFi or other suitable wireless communication standards), and / or any combination thereof. A base station may include at least one gNB central unit (gNB-CU) and at least one gNB distributed unit (gNB-DU).

[0065] The base stations included in RAN104 may include a set of one or more antennas for communicating with the wireless device 106 over the air interface. For example, one or more base stations may include three sets of antennas for controlling three cells (or sectors) respectively. The size of a cell may be determined by the range within which a receiver (e.g., a base station receiver) can successfully receive transmissions from a transmitter (e.g., a wireless device transmitter) operating in the cell. Together, the cells of the base stations may provide wireless coverage to the wireless device 106 over a wide geographic area to support wireless device mobility.

[0066] In addition to the three-sector site, other implementations of the base station are possible. For example, one or more base stations of RAN104 may be implemented as a sector site having more than three or less than three sectors. One or more base stations of RAN104 may be implemented as an access point, as a baseband processing unit coupled to a plurality of remote radio heads (RRHs), and / or as a repeater or relay node used to extend the coverage area of a donor node. The baseband processing unit coupled to the RRH may be part of a centralized or cloud RAN architecture, and the baseband processing unit may be centralized within a pool of baseband processing units or may be virtualized. A repeater node may amplify and rebroadcast a wireless signal received from a donor node. A relay node may perform the same / similar functions as a repeater node, but may decode a wireless signal received from a donor node and remove noise before amplifying and rebroadcasting the wireless signal.

[0067] RAN 104 can be deployed as a homogeneous network of macrocell base stations having similar antenna patterns and similar high-level transmission powers. RAN 104 can be deployed as a heterogeneous network. In a heterogeneous network, small cell base stations can be used to provide small coverage areas, for example, coverage areas that overlap with the relatively large coverage area provided by a macrocell base station. The small coverage areas can be provided in areas with high data traffic (or so-called hotspots), or areas with weak macrocell coverage. Examples of small cell base stations include microcell base stations, picocell base stations, and femtocell base stations or home base stations, in order of decreasing coverage area.

[0068] The Third Generation Partnership Project (3GPP™) was formed in 1998 to provide global standardization of the specifications of mobile communication networks similar to the mobile communication network 100 of FIG. 1A. To date, 3GPP™ has produced the specifications of three generations of mobile networks, namely, the third generation (3G) network known as the Universal Mobile Telecommunications System (UMTS), the fourth generation (4G) network known as Long Term Evolution (LTE), and the fifth generation (5G) network known as the 5G System (5GS). Embodiments of the present disclosure are described with reference to the RAN of the 3GPP™ 5G network, referred to as the Next Generation RAN (NG-RAN). The embodiments can be applicable to the RANs of other mobile communication networks such as the RAN 104 of FIG. 1A, the RANs of previous 3G and 4G networks, and future networks not yet specified (e.g., the 3GPP™ 6G network). The NG-RAN implements the 5G radio access technology known as New Radio (NR) and can be supplied to implement other radio access technologies including 4G radio access technology or non-3GPP™ radio access technology.

[0069] Figure 1B shows a mobile communication network 150 of another example in which an embodiment of the present disclosure can be implemented. The mobile communication network 150 can be, for example, a PLMN executed by a network operator. As shown in Figure 1B, the mobile communication network 150 includes a 5G core network (5G-CN) 152, an NG-RAN 154, and UEs 156A and 156B (collectively UEs 156). These components can be implemented and operate in the same or similar manner as the corresponding components described with respect to Figure 1A.

[0070] The 5G-CN 152 provides an interface for the UEs 156 to one or more DNs such as a public DN (e.g., the Internet), a private DN, and / or an operator-internal DN. As part of the interface function, the 5G-CN 152 can set up an end-to-end connection between the UEs 156 and one or more DNs, authenticate the UEs 156, and provide a charging function. Compared with the CN of the 3GPP (registered trademark) 4G network, the base of the 5G-CN 152 can be a service-based architecture. This means that the architecture of the nodes constituting the 5G-CN 152 can be defined as a network function that provides services via an interface to other network functions. The network functions of the 5G-CN 152 can be implemented in several ways, as network elements on dedicated or shared hardware, as software instances operating on dedicated or shared hardware, or as virtualized functions instantiated on a platform (e.g., a cloud-based platform).

[0071] As shown in FIG. 1B, 5G-CN152 includes an Access and Mobility Management Function (AMF) 158A and a User Plane Function (UPF) 158B, which, for simplicity of explanation, are shown as a single component AMF / UPF158 in FIG. 1B. UPF158B can function as a gateway between NG-RAN154 and one or more DNs. UPF158B can perform functions such as packet routing and forwarding, packet inspection and enforcement of user plane policy rules, reporting of traffic usage, uplink classification to support routing of traffic flows to one or more DNs, Quality of Service (QoS) handling for the user plane (e.g., packet filtering, gating, uplink / downlink rate enforcement, and uplink traffic verification), downlink packet buffering, and downlink data notification triggering. UPF158B can function as an anchor point for intra / inter Radio Access Technology (RAT) mobility, an external protocol (or packet) Data Unit (PDU) session point interconnected to one or more DNs, and / or a branching point to support multi-home PDU sessions. UE156 can be configured to receive services via a PDU session, which is a logical connection between the UE and the DN.

[0072] AMF158A can perform functions such as termination of non-access stratum (NAS) signaling, NAS signaling security, access stratum (AS) security control, inter-CN node signaling for mobility between 3GPP (registered trademark) access networks, idle mode UE reachability (e.g., control and execution of paging retransmission), registration area management, in-system and inter-system mobility support, access authentication, access authorization including checking of roaming rights, mobility management control (subscription and policy), support for network slicing, and / or selection of a Session Management Function (SMF). NAS may refer to functions operating between the CN and the UE, and AS may refer to functions operating between the UE and the RAN.

[0073] 5G-CN152 may include one or more additional network functions not shown in FIG. 1B for clarity. For example, 5G-CN152 may include one or more of a session management function (SMF), an NR repository function (NRF), a policy control function (PCF), a network exposure function (NEF), a unified data management (UDM), an application function (AF), and / or an authentication server function (AUSF).

[0074] NG-RAN154 may connect 5G-CN 152 to UE156 via wireless communication on the air interface. NG-RAN154 may include one or more gNBs (collectively gNB160) illustrated as gNB160A and gNB160B and / or one or more ng-eNBs (collectively ng-eNB162) illustrated as ng-eNB162A and ng-eNB162B. gNB160 and ng-eNB162 may more generally be referred to as base stations. gNB160 and ng-eNB162 may include a set of one or more antennas for communicating with UE156 on the air interface. For example, one or more of gNB160 and / or one or more of ng-eNB162 may include three antenna sets for controlling three cells (or sectors) respectively. Collectively, the cells of gNB160 and ng-eNB162 may provide wireless coverage to UE156 over a wide geographic area to support UE mobility.

[0075] As shown in FIG. 1B, gNB 160 and / or ng-eNB 162 may be connected to 5G-CN 152 via the NG interface and may be connected to other base stations via the Xn interface. The NG and Xn interfaces may be established using direct physical connections and / or indirect connections over an underlying transport network such as an Internet Protocol (IP) transport network. gNB 160 and / or ng-eNB 162 may be connected to UE 156 via the Uu interface. For example, as shown in FIG. 1B, gNB 160A may be connected to UE 156A via the Uu interface. The NG, Xn, and Uu interfaces are associated with protocol stacks. The protocol stacks associated with the interfaces may be used by the network elements in FIG. 1B to exchange data and signaling messages and may include two planes: a user plane and a control plane. The user plane may process data of interest to the user. The control plane may process signaling messages of interest to the network elements.

[0076] gNB 160 and / or ng-eNB 162 may be connected to one or more AMF / UPF functions of 5G-CN 152, such as AMF / UPF 158, via one or more NG interfaces. For example, gNB 160A may be connected to UPF 158B of AMF / UPF 158 via the NG user plane (NG-U) interface. The NG-U interface may provide the supply of user plane PDUs between gNB 160A and UPF 158B (e.g., non-guaranteed delivery). gNB 160A may be connected to AMF 158A using the NG control plane (NG-C) interface. The NG-C interface may provide, for example, NG interface management, UE context management, UE mobility management, NAS message transfer, paging, PDU session management and configuration transfer and / or warning message transmission.

[0077] gNB 160 may provide NR user plane and control plane protocol termination towards UE 156 on the Uu interface. For example, gNB 160A may provide NR user plane and control plane protocol termination towards UE 156A on the Uu interface associated with the first protocol stack. ng-eNB 162 may provide Evolved UMTS Terrestrial Radio Access (E-UTRA) user plane and control plane protocol termination towards UE 156 on the Uu interface, where E-UTRA refers to the 3GPP (registered trademark) 4G radio access technology. For example, ng-eNB 162B may provide E-UTRA user plane and control plane protocol termination towards UE 156B on the Uu interface associated with the second protocol stack.

[0078] 5G-CN 152 was described as being configured to handle NR and 4G radio access. One skilled in the art will understand that it may be possible for NR to connect to a 4G core network in a mode known as "non-standalone operation". In non-standalone operation, the 4G core network is used to provide (or at least support) control plane functions such as initial access, mobility, and paging. Only one AMF / UPF 158 is shown in Figure 1B, but one gNB or ng-eNB may be connected to multiple AMF / UPF nodes to provide redundancy and / or load sharing across multiple AMF / UPF nodes.

[0079] As discussed, in Figure 1B, interfaces between network elements (e.g., Uu, Xn, and NG interfaces) may be associated with protocol stacks that network elements use to exchange data and signaling messages. The protocol stack may include two planes, namely, a user plane and a control plane. The user plane may process data of interest to the user, and the control plane may process signaling messages of interest to the network element.

[0080] Figures 2A and 2B respectively show examples of an NR user plane and an NR control plane protocol stack for the Uu interface between UE210 and gNB220. The protocol stacks shown in Figures 2A and 2B may be the same as or similar to those used for the Uu interface between UE156A and gNB160A shown in Figure 1B.

[0081] Figure 2A shows an NR user plane protocol stack including five layers implemented in UE210 and gNB220. At the bottom of the protocol stack, physical layers (PHYs) 211 and 221 may provide a transport service to the upper layers of the protocol stack and may correspond to layer 1 of the Open Systems Interconnection (OSI) model. The next four protocols above PHY211 and 221 include a media access control layer (MAC) 212 and 222, a radio link control layer (RLC) 213 and 223, a packet data convergence protocol layer (PDCP) 214 and 224, and a service data application protocol layer (SDAP) 215 and 225. Collectively, these four protocols may constitute layer 2 or the data link layer of the OSI model.

[0082] Figure 3 shows an example of services provided between protocol layers of the NR user plane protocol stack. Starting from the top in FIGS. 2A and 3, SDAPs 215 and 225 may perform QoS flow processing. The UE 210 may receive services via a PDU session, which may be a logical connection between the UE 210 and the DN. The PDU session may have one or more QoS flows. The UP function of the CN (e.g., UPF 158B) may map IP packets to one or more QoS flows of the PDU session based on QoS requirements (e.g., regarding latency, data rate, and / or error rate). SDAPs 215 and 225 may perform mapping / demapping between one or more QoS flows and one or more data radio bearers. The mapping / demapping between the QoS flow and the data radio bearer may be determined by the SDAP 225 at the gNB 220. The SDAP 215 at the UE 210 may be notified about the mapping between the QoS flow and the data radio bearer via reflected mapping or control signaling received from the gNB 220. For reflected mapping, the SDAP 225 at the gNB 220 may mark downlink packets with a QoS flow indicator (QFI) that can be observed by the SDAP 215 of the UE 210 to determine the mapping / demapping between the QoS flow and the data radio bearer.

[0083] PDCP214 and PDCP224 may perform header compression / decompression to reduce the amount of data that needs to be transmitted over the air interface, encryption / decryption to prevent unauthorized decryption of the data transmitted over the air interface, and integrity protection (to ensure that control messages are sent from the intended source). PDCP214 and 224 may perform, for example, retransmission of unsent packets, in-sequence delivery and re-sequencing of packets, and removal of duplicate packets received for gNB-internal handover. PDCP214 and 224 may perform packet duplication to improve the likelihood of received packets and to remove any duplicate packets at the receiver. Packet duplication may be useful for services that require high reliability.

[0084] Although not shown in Figure 3, PDCP214 and 224 may perform mapping / demapping between split radio bearers and RLC channels in a dual-connectivity scenario. Dual connectivity is a technique that enables a UE to connect to two cells, or more generally, two cell groups of a master cell group (MCG) and a secondary cell group (SCG). A split bearer is when a single radio bearer, such as one provided by PDCP214 and 224 as a service to SDAP215 and 225, is processed by cell groups in a dual-connectivity. PDCP214 and 224 may map / demap a split radio bearer between RLC channels belonging to cell groups.

[0085] RLC 213 and 223 can each perform segmentation, retransmission through automatic repeat request (ARQ), and removal of duplicate data units received from MAC 212 and 222. RLC 213 and 223 can support three transmission modes: transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM). Based on the transmission mode in which the RLC is operating, the RLC can perform one or more of the indicated functions. This RLC configuration can be per logical channel without depending on numerology and / or transmission time interval (TTI) duration. As shown in Figure 3, RLC 213 and 223 can each provide an RLC channel as a service to PDCP 214 and 224.

[0086] MAC212 and MAC222 may perform multiplexing / demultiplexing of logical channels and / or mapping between logical channels and transport channels. Multiplexing / demultiplexing may include multiplexing / demultiplexing of data units belonging to one or more logical channels to / from transport blocks (TBs) delivered to / from PHY211 and 221. MAC222 may be configured to perform scheduling, scheduling information reporting, and prioritization among UEs by dynamic scheduling. Scheduling may be performed at gNB220 (at MAC222) for downlink and uplink. MAC212 and 222 may be configured to perform error correction, prioritization between logical channels of UE210 by logical channel prioritization, and / or padding through hybrid automatic repeat request (HARQ) (e.g., one HARQ entity per carrier in the case of carrier aggregation (CA)). MAC212 and MAC222 may support one or more numerologies and / or transmission timings. In one embodiment, the mapping restrictions in logical channel prioritization can control which numerology and / or transmission timing a logical channel can use. As shown in Figure 3, MAC212 and 222 may provide logical channels to RLC213 and 223 as a service.

[0087] PHY211 and 221 may perform mapping of transport channels to physical channels and digital and analog signal processing functions to transmit and receive information on the air interface. These digital and analog signal processing functions may include, for example, encoding / decoding and modulation / demodulation. PHY211 and 221 may perform multi-antenna mapping. As shown in Figure 3, PHY211 and 221 may provide one or more transport channels to MAC212 and 222 as a service.

[0088] Figure 4A shows an example of downlink data flow through the NR user plane protocol stack. Figure 4A shows the downlink data flow of three IP packets (n, n+1, and m) through the NR user plane protocol stack, and generates two transport blocks at gNB 220. The uplink data flow through the NR user plane protocol stack may be similar to the downlink data flow shown in Figure 4A.

[0089] The downlink data flow in Figure 4A starts when SDAP 225 receives three IP packets from one or more QoS flows and maps the three packets to radio bearers. In Figure 4A, SDAP 225 maps IP packets n and n+1 to the first radio bearer 402 and IP packet m to the second radio bearer 404. An SDAP header (labeled "H" in Figure 4A) is added to the IP packets. Data units from / to higher protocol layers are called service data units (SDUs) of lower protocol layers, and data units to / from lower protocol layers are called protocol data units (PDUs) of higher protocol layers. As shown in Figure 4A, the data unit from AP 225 is the SDU of the lower protocol layer PDCP 224 and the PDU of SDAP 225.

[0090] The remaining protocol layers in FIG. 4A can perform related functions (e.g., with respect to FIG. 3), add corresponding headers, and transfer each output to the next lower layer. For example, PDCP 224 can perform IP header compression and encryption and transfer its output to RLC 223. RLC 223 can optionally perform segmentation (e.g., as shown for IP packet m in FIG. 4A) and transfer its output to MAC 222. MAC 222 may multiplex several RLC PDUs and attach a MAC sub-header to the RLC PDU to form a transport block. In NR, as shown in FIG. 4A, the MAC sub-header can be distributed over the entire MAC PDU. In LTE, the MAC sub-header can be placed entirely at the beginning of the MAC PDU. The NR MAC PDU structure can reduce processing time and related latency because the MAC PDU sub-header can be calculated before the complete MAC PDU is assembled.

[0091] FIG. 4B shows an example format of the MAC sub-header in the MAC PDU. The MAC sub-header includes an SDU length field for indicating the length (such as in bytes) of the MAC SDU corresponding to the MAC sub-header, a logical channel identifier (LCID) field for identifying the logical channel on which the MAC SDU started to assist the demultiplexing process, a flag (F) for indicating the size of the SDU length field, and a reserved bit (R) field for future use.

[0092] Figure 4B further shows MAC control elements (CEs) inserted into the MAC PDU by a MAC such as MAC223 or MAC222. For example, Figure 4B shows two MAC CEs inserted into the MAC PDU. The MAC CE can be inserted at the start of the MAC PDU for downlink transmission (as shown in Figure 4B) and at the end of the MAC PDU for uplink transmission. The MAC CE can be used for in-band control signaling. Examples of MAC CEs include scheduling-related MAC CEs such as buffer status reports and power headroom reports, activation / deactivation MAC CEs for PDCP duplicate detection, channel state information (CSI) reports, sounding reference signal (SRS) transmission, and activation / deactivation for preconfigured components, discontinuous reception (DRX)-related MAC CEs, timing advance MAC CEs, and random access-related MAC CEs. The MAC CE may be preceded by a MAC sub-header in a format similar to that described for the MAC SDU and can be identified by a reserved value in an LCID field indicating the type of control information included in the MAC CE.

[0093] Before describing the NR control plane protocol stack, the logical channels, transport channels, and physical channels, as well as the mapping between channel types, are first described. One or more channels can be used to perform functions related to the NR control plane protocol stack described below.

[0094] Figures 5A and 5B show the mapping between logical channels, transport channels, and physical channels for the downlink and uplink, respectively. Information is transmitted through channels between the RLC, MAC, and PHY of the NR protocol stack. Logical channels can be used between the RLC and MAC and can be classified as control channels that convey control and configuration information within the NR control plane or as traffic channels that convey data within the NR user plane. Logical channels can be classified as dedicated logical channels specific to a particular UE or as common logical channels that can be used by multiple UEs. Logical channels can also be defined by the type of information they carry. The set of logical channels defined by NR includes, for example, - A paging control channel (PCCH) for displaying paging messages used to page UEs whose location is not known to the network at the cell level, - A broadcast control channel (BCCH) for transmitting system information messages in the form of a master information block (MIB) and some system information blocks (SIBs), where the system information messages can be used by the UE to obtain information about how the cell is configured and how it operates within the cell, - A common control channel (CCCH) for transmitting control messages along with random access, - A dedicated control channel (DCCH) for transmitting control messages between a particular UE to configure the UE, - And a dedicated traffic channel (DTCH) for transmitting user data between a particular UE.

[0095] Transport channels are used between the MAC layer and the PHY layer and can be defined by how the information they carry is transmitted on the air interface. The set of transport channels defined by NR includes, for example, - A paging channel (PCH) for transmitting paging messages sent from the PCCH, - A broadcast channel (BCH) for carrying the MIB from the BCCH, - A downlink shared channel (DL-SCH) for transmitting downlink data and signaling messages, including the SIB from the BCCH - An uplink shared channel (UL-SCH) for transmitting uplink data and signaling messages, - A random access channel (RACH) that enables the UE to connect to the network without prior scheduling.

[0096] The PHY can pass information between processing levels of the PHY using physical channels. A physical channel may have an associated set of time-frequency resources for carrying information of one or more transport channels. The PHY can generate control information to support the low-level operation of the PHY and provide the control information to the low level of the PHY via a physical control channel known as the L1 / L2 control channel. The set of physical channels and physical control channels defined by NR is, for example, - A physical broadcast channel (PBCH) for carrying the MIB from the BCH, - A physical downlink shared channel (PDSCH) for carrying downlink data and signaling messages from the DL-SCH, as well as paging messages from the PCH, - A physical downlink control channel (PDCCH) for carrying downlink control information (DCI) that may include downlink scheduling commands, uplink scheduling grants, and uplink power control commands, - A physical uplink shared channel (PUSCH) for carrying uplink data and signaling messages from the UL-SCH and, in some examples, uplink control information (UCI) as described below, - A physical uplink control channel (PUCCH) for carrying UCI, which may include HARQ acknowledgment responses, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and scheduling requests (SR), and - A physical random access channel (PRACH) for random access, are included.

[0097] Similar to the physical control channel, the physical layer generates physical signals to support the low-level operations of the physical layer. As shown in FIGS. 5A and 5B, the physical layer signals defined by NR include primary synchronization signals (PSS), secondary synchronization signals (SSS), channel state information reference signals (CSI-RS), demodulation reference signals (DMRS), sounding reference signals (SRS), and phase tracking reference signals (PT-RS). These physical layer signals are described in more detail below.

[0098] FIG. 2B shows an example of the NR control plane protocol stack. In FIG. 2B, the NR control plane protocol stack may use the same / first four protocol layers similar to those of the NR user plane protocol stack example. These four protocol layers include PHY211 and 221, MAC212 and 222, RLC213 and 223, and PDCP214 and 224. Instead of having SDAP215 and 225 at the top of the stack like the NR user plane protocol stack, the NR control plane stack has radio resource control (RRC) 216 and 226, and NAS protocol 217 and 237 at the top of the NR control plane protocol stack.

[0099] The NAS protocols 217 and 237 can provide control plane functions between the UE 210 and the AMF 230 (e.g., AMF 158A), or more generally, between the UE 210 and the CN. The NAS protocols 217 and 237 can provide control plane functions between the UE 210 and the AMF 230 via signaling messages called NAS messages. There is no direct path for sending NAS messages between the UE 210 and the AMF 230. NAS messages can be sent using the AS of the Uu and NG interfaces. The NAS protocols 217 and 237 can provide control plane functions such as authentication, security, connection setup, mobility management, and session management.

[0100] The RRCs 216 and 226 can provide control plane functions between the UE 210 and the gNB 220, or more generally, between the UE 210 and the RAN. The RRCs 216 and 226 can provide control plane functions between the UE 210 and the gNB 220 via signaling messages called RRC messages. RRC messages can be sent between the UE 210 and the RAN using signaling radio bearers and the same / similar PDCP, RLC, MAC, and PHY protocol layers. The MAC can multiplex control plane and user plane data within the same transport block (TB). The RRCs 216 and 226 can provide control plane functions including broadcast of system information related to the AS and NAS, paging initiated by the CN or RAN, establishment, maintenance, and release of the RRC connection between the UE 210 and the RAN, security functions including key management, establishment, configuration, maintenance, and release of signaling and data radio bearers, mobility functions, QoS management functions, UE measurement report and report control, detection and recovery of radio link failure (RLF), and / or transfer of NAS messages. As part of the establishment of the RRC connection, the RRCs 216 and 226 can establish an RRC context, which may involve setting parameters for communication between the UE 210 and the RAN.

[0101] FIG. 6 is an exemplary diagram showing the RRC state transition of a UE. The UE can be the same as or similar to the wireless device 106 shown in FIG. 1A, the UE 210 shown in FIGS. 2A and 2B, or any other wireless device described in the present disclosure. As shown in FIG. 6, the UE can be in at least one of three RRC states. That is, RRC connection 602 (e.g., RRC_CONNECTED), RRC idle 604 (e.g., RRC_IDLE), and RRC inactive 606 (e.g., RRC_INACTIVE).

[0102] In RRC connection 602, the UE may have an established RRC context and have at least one RRC connection with a base station. The base station may be one of one or more base stations included in RAN104 shown in FIG. 1A, one of gNB160 or ng-eNB162 shown in FIG. 1B, gNB220 shown in FIGS. 2A and 2B, or similar to any other base station described in the present disclosure. There may be an RRC context of the UE in the base station to which the UE is connected. The RRC context, called the UE context, may include parameters for communication between the UE and the base station. These parameters may include, for example, one or more AS contexts, one or more radio link configuration parameters, bearer configuration information (e.g., related to data radio bearers, signaling radio bearers, logical channels, QoS flows, and / or PDU sessions), security information, and / or PHY, MAC, RLC, PDCP, and / or SDAP layer configuration information. In RRC connection 602, the mobility of the UE may be managed by the RAN (e.g., RAN104 or NG-RAN154). The UE may measure the signal levels (e.g., reference signal levels) from the serving cell and adjacent cells and report these measurements to the base station currently providing service to the UE. The serving base station of the UE may request a handover to a cell of one of the adjacent base stations based on the reported measurements. The RRC state may transition from RRC connection 602 to RRC idle 604 via the connection release procedure 608, or may transition to RRC inactive 606 via the connection deactivation procedure 610.

[0103] In RRC idle 604, the RRC context cannot be established for the UE. In RRC idle 604, the UE cannot have an RRC connection with the base station. During RRC idle 604, the UE can be in a sleep state most of the time (e.g., to save battery power). The UE can wake up periodically (e.g., once per discontinuous reception cycle) to monitor paging messages from the RAN. The mobility of the UE can be managed by the UE through a procedure known as cell reselection. The RRC state can transition from RRC idle 604 to RRC connection 602 via a connection establishment procedure 612 that may involve a random access procedure as discussed in more detail below.

[0104] In RRC inactive 606, the previously established RRC context is maintained at the UE and the base station. This reduces the signaling overhead and enables a fast transition to RRC connection 602 compared to the transition from RRC idle 604 to RRC connection 602. In RRC inactive 606, the UE is in a sleep state and the mobility of the UE can be managed by the UE through cell reselection. The RRC state can transition from RRC inactive 606 to RRC connection 602 by a connection resume procedure 614, or to RRC idle 604 via a connection release procedure 616 that is the same as or similar to the connection release procedure 608.

[0105] The RRC state may be associated with the mobility management entity. In RRC idle 604 and RRC inactive 606, mobility is managed by the UE through cell reselection. The purpose of mobility management in RRC idle 604 and RRC inactive 606 is to enable the network to notify the UE of events via paging messages without having to broadcast the paging messages across the entire mobile communication network. The mobility management entity used in RRC idle 604 and RRC inactive 606 may enable the network to track the UE at the cell group level such that paging messages can be broadcast on the cells of the cell group in which the UE is currently located instead of across the entire mobile communication network. The mobility management entity for RRC idle 604 and RRC inactive 606 tracks the UE at the cell group level. They can do so using different granularities of grouping. For example, there can be three levels of granularity of cell grouping, namely, individual cells, cells within a RAN area identified by a RAN area identifier (RAI), and cells within a group of RAN areas called a tracking area and identified by a tracking area identifier (TAI).

[0106] The tracking area may be used to track the UE at the CN level. The CN (e.g., CN102 or 5G-CN152) may provide the UE with a list of TAIs associated with the UE registration area. If the UE moves, through cell reselection, to a cell associated with a TAI that is not included in the list of TAIs associated with the UE registration area, the UE may perform a registration update with the CN so that the CN can update the UE's location and may provide the UE with a new UE registration area.

[0107] The RAN area can be used to track the UE at the RAN level. For a UE in the RRC inactive 606 state, a RAN notification area can be assigned to the UE. The RAN notification area may include one or more cell identities, a list of RAI, or a list of TAI. In one embodiment, the base station may belong to one or more RAN notification areas. In one embodiment, a cell can belong to one or more RAN notification areas. When the UE moves to a cell not included in the RAN notification area assigned to the UE through cell reselection, the UE can perform an update of the notification area in the RAN and update the RAN notification area of the UE.

[0108] The base station storing the RRC context for the UE, or the last serving base station of the UE, may be referred to as the anchor base station. The anchor base station can maintain the RRC context for the UE at least during the time the UE stays in the RAN notification area of the anchor base station and / or during the time the UE stays in RRRC inactive 606.

[0109] A gNB such as gNB160 in FIG. 1B can be divided into two parts, namely a central unit (gNB-CU), and one or more distributed units (gNB-DU). The gNB-CU can be coupled to one or more gNB-DUs using the F1 interface. The gNB-CU may include RRC, PDCP, and SDAP. The gNB-DU may include RLC, MAC, and PHY.

[0110] In NR, physical signals and physical channels (Figs. 5A and 5B) can be mapped onto orthogonal frequency division multiplexing (OFDM) symbols. OFDM is a multi-carrier communication scheme that transmits data over F orthogonal sub-carriers (or tones). Before transmission, the data can be mapped to a series of complex symbols (e.g., M quadrature amplitude modulation (M-QAM) or M phase shift keying (M-PSK) symbols), which are called source symbols and are split into F parallel symbol streams. The F parallel symbol streams are treated as if they were in the frequency domain and can be used as inputs to an inverse fast Fourier transform (IFFT) block that converts them to the time domain. The IFFT block can take one from each of the F parallel symbol streams at a time, capture it as an F source symbol, and use each source symbol to modulate the amplitude and phase of one of the F sine-wave basis functions corresponding to the F orthogonal sub-carriers. The output of the IFFT block can be F time-domain samples representing the sum of the F orthogonal sub-carriers. The F time-domain samples can form a single OFDM symbol. After some processing (e.g., adding a cyclic prefix) and up-conversion, the OFDM symbol provided by the IFFT block can be transmitted over the air interface at the carrier frequency. The F parallel symbol streams can be mixed using an FFT block before being processed by the IFFT block. This process can generate pre-coded OFDM symbols with discrete Fourier transform (DFT) and be used by a UE in the uplink to reduce the peak-to-average power ratio (PAPR). The reverse process can be performed on the OFDM symbol at the receiver using an FFT block to recover the data mapped to the source symbols.

[0111] Figure 7 shows a configuration example of an NR frame in which OFDM symbols are grouped. The NR frame can be identified by a system frame number (SFN). The SFN can be repeated over a period of 1024 frames. As shown in the figure, one NR frame may have a duration of 10 milliseconds (ms) or may include 10 subframes each having a duration of 1 ms. A subframe can be divided, for example, into slots each including 14 OFDM symbols per slot.

[0112] The duration of a slot can depend on the numerology used for the OFDM symbols of the slot. In NR, flexible numerology is supported to accommodate different cell deployments (e.g., cells with carrier frequencies less than 1 GHz up to cells with carrier frequencies in the maximum mmWave range). Numerology can be defined with respect to the subcarrier spacing and the cyclic prefix duration. For numerology in NR, the subcarrier spacing may be scaled up by a power of 2 from a baseline subcarrier spacing of 15 kHz, and the cyclic prefix duration may be scaled down by a power of 2 from a baseline cyclic prefix duration of 4.7 μs. For example, NR defines numerology using the following combinations of subcarrier spacing / cyclic prefix duration: 15 kHz / 4.7 μs, 30 kHz / 2.3 μs, 60 kHz / 1.2 μs, 120 kHz / 0.59 μs, and 240 kHz / 0.29 μs.

[0113] A slot may have a fixed number of OFDM symbols (e.g., 14 OFDM symbols). Numerologies with higher subcarrier spacing have shorter slot durations and, correspondingly, more slots per subframe. FIG. 7 shows this numerology-dependent slot duration and slot transmission structure per subframe (for ease of illustration, the numerology with a 240 kHz subcarrier spacing is not shown in FIG. 7). Subframes within NR may be used as numerology-independent time references, while slots may be used as units in which uplink and downlink transmissions are scheduled. For low-latency support, scheduling in NR is separated from the slot duration and may start at any OFDM symbol and end with as many symbols as necessary for transmission. These partial slot transmissions may also be referred to as mini-slot transmissions or sub-slot transmissions.

[0114] FIG. 8 shows an example configuration of a slot in the time and frequency domains of an NR carrier. A slot contains resource elements (REs) and resource blocks (RBs). An RE is the smallest physical resource in NR. As shown in FIG. 8, an RE spans one OFDM symbol in the time domain by one subcarrier in the frequency domain. An RB spans 12 consecutive REs in the frequency domain as shown in FIG. 8. An NR carrier may be limited to a width of 275 RBs or 275×12 = 3300 subcarriers. These limitations, if used, may limit the NR carrier to 50, 100, 200, and 400 MHz for subcarrier spacings of 15, 30, 60, and 120 kHz, respectively, and a 400 MHz bandwidth may be set based on 400 MHz per carrier bandwidth limitation.

[0115] FIG. 8 shows a single numerology used across the full bandwidth of an NR carrier. In other exemplary configurations, multiple numerologies may be supported on the same carrier.

[0116] NR can support a wide carrier bandwidth (e.g., up to 400 MHz for a 120 kHz sub-carrier spacing). Not all UEs can receive the full carrier bandwidth (e.g., due to hardware limitations, etc.). Also, receiving the full carrier bandwidth may be prohibited from the perspective of the UE's power consumption. In one embodiment, to reduce power consumption and / or for other purposes, the UE may adapt the size of its receive bandwidth based on the amount of traffic the UE expects to receive. This is called bandwidth adaptation.

[0117] NR supports UEs that cannot receive the full carrier bandwidth and defines a bandwidth part (BWP) that supports bandwidth adaptation. In one embodiment, a BWP may be defined by a subset of consecutive RBs on a carrier. A UE may be configured (e.g., via the RRC layer) with one or more downlink BWPs and one or more uplink BWPs per serving cell (e.g., up to four downlink BWPs and up to four uplink BWPs per serving cell). At a given time, one or more of the BWPs configured for a serving cell may be active. These one or more BWPs may be referred to as the active BWPs of the serving cell. When the serving cell is composed of a secondary uplink carrier, the serving cell may have one or more first active BWPs on the uplink carrier and one or more second active BWPs on the secondary uplink carrier.

[0118] For unpaired spectrum, when the downlink BWP index of the downlink BWP is the same as the uplink BWP index of the uplink BWP, the downlink BWP from the set of configured downlink BWPs may be linked to the uplink BWP from the set of configured uplink BWPs. For unpaired spectrum, the UE may expect that the center frequency of the downlink BWP is the same as the center frequency of the uplink BWP.

[0119] For a downlink BWP within a set of configured downlink BWPs on a primary cell (PCell), the base station may configure the UE for at least one search space with one or more control resource sets (CORESETs). A search space is a set of positions in the time and frequency domains where the UE can find control information. The search space can be a UE-specific search space or a common search space (potentially usable by multiple UEs). For example, the base station can configure the UE with a common search space on the PCell or on a primary secondary cell (PSCell) in an active downlink BWP.

[0120] For an uplink BWP within a set of configured uplink BWPs, the BS can configure the UE with one or more resource sets for one or more PUCCH transmissions. The UE can receive downlink receptions (e.g., PDCCH or PDSCH) within the downlink BWP according to the numerology configured for the downlink BWP (e.g., subcarrier spacing and cyclic prefix duration). The UE can transmit uplink transmissions (e.g., PUCCH or PUSCH) within the uplink BWP according to the numerology configured (e.g., subcarrier spacing and cyclic prefix length of the uplink BWP).

[0121] One or more BWP indicator fields may be provided in the downlink control information (DCI). The value of the BWP indicator field may indicate which BWP in the set of configured BWPs is the active downlink BWP for one or more downlink receptions. The value of one or more BWP indicator fields may indicate the active uplink BWP for one or more uplink transmissions.

[0122] The base station may semi-statically configure the UE with the default downlink BWP within the set of configured downlink BWPs associated with the PCell. If the base station does not provide a default downlink BWP for the UE, the default downlink BWP may be the initial active downlink BWP. The UE may determine which BWP is the initial active downlink BWP based on the CORESET configuration obtained using the PBCH.

[0123] The base station may configure the UE with the BWP Inactive timer value. The UE may start or restart the BWP Inactive timer at any appropriate time. For example, (a) when the UE detects DCI indicating an active downlink BWP other than the default downlink BWP for paired spectrum operation, or (b) when the UE detects DCI indicating an active downlink BWP or active uplink BWP other than the default downlink BWP or uplink BWP for unpaired spectrum operation, the UE may start or restart the BWP Inactive timer. If the UE does not detect DCI for a certain period (e.g., 1 millisecond or 0.5 millisecond), the UE may run the BWP Inactive timer towards expiration (e.g., increment from zero to the BWP Inactive timer value or decrement from the BWP Inactive timer value to zero). When the BWP Inactive timer expires, the UE may be switched from the active downlink BWP to the default downlink BWP.

[0124] In one embodiment, the base station may semi-statically configure a UE having one or more BWPs. The UE may switch the active BWP from the first BWP to the second BWP in response to receiving DCI indicating the second BWP as the active BWP and / or in response to the expiration of the BWP Inactive timer (e.g., when the second BWP is the default BWP).

[0125] Downlink and uplink BWP switching (where BWP switching refers to switching from the currently active BWP to a non-currently active BWP) may be performed independently in a pair of spectrums. In non-pair spectrums, downlink and uplink BWP switching may be performed simultaneously. The switching between configured BWPs may occur based on RRC signaling, DCI, expiration of the BWP inactive timer, and / or the start of random access.

[0126] Figure 9 shows an example of bandwidth adaptation using three configured BWPs for an NR carrier. A UE configured with three BWPs may switch from one BWP to another at a switching point. In the example shown in Figure 9, the BWPs include BWP902 with a bandwidth of 40 MHz and a subcarrier spacing of 15 kHz, BWP904 with a bandwidth of 10 MHz and a subcarrier spacing of 15 kHz, and BWP906 with a bandwidth of 20 MHz and a subcarrier spacing of 60 kHz. BWP902 may be the initial active BWP, and BWP904 may be the default BWP. The UE may switch between BWPs at the switching point. In the example of Figure 9, the UE may switch from BWP902 to BWP904 at switching point 908. The switching at switching point 908 may occur for any suitable reason, for example, in response to the expiration of a BWP inactive timer (indicating a switch to the default BWP) and / or in response to receiving DCI indicating BWP904 as the active BWP. The UE may switch from active BWP904 to BWP906 at switching point 910 in response to receiving DCI indicating BWP906 as the active BWP. The UE may switch from active BWP906 to BWP904 at switching point 912 in response to the expiration of the BWP inactive timer and / or in response to receiving DCI indicating BWP904 as the active BWP. The UE may switch from active BWP904 to BWP902 at switching point 914 in response to receiving DCI indicating BWP902 as the active BWP.

[0127] If the UE is configured for a secondary cell with a set of configured downlink BWPs and a default downlink BWP in timer values, the UE procedures for switching the BWP on the secondary cell can be the same / similar to those on the primary cell. For example, the UE can use the timer values and the default downlink BWP for the secondary cell in the same / similar manner as it uses these values for the primary cell.

[0128] To provide a larger data rate, carrier aggregation (CA) can be used to aggregate two or more carriers and transmit simultaneously between the same UEs. The aggregated carriers of CA may also be referred to as component carriers (CCs). When using CA, there are multiple serving cells for the UE and one cell for the CC. The CC can have three configurations within the frequency domain.

[0129] Figure 10A shows three CA configurations with two CCs. In the in-band, contiguous configuration 1002, the two CCs are aggregated in the same frequency band (frequency band A) and are placed directly adjacent to each other within the frequency band. In the in-band, non-contiguous configuration 1004, the two CCs are aggregated in the same frequency band (frequency band A) and are separated by a gap within the frequency band. In the in-band configuration 1006, the two CCs are located in frequency bands (frequency band A and frequency band B).

[0130] In one embodiment, up to 32 CCs can be aggregated. The aggregated CCs can have the same or different bandwidths, subcarrier spacings, and / or duplexing schemes (TDD or FDD). The serving cell of a UE using CA can have a downlink CC. For FDD, one or more uplink CCs can optionally be configured for the serving cell. The ability to aggregate more downlink carriers than uplink carriers can be useful, for example, when the UE has more data traffic in the downlink than in the uplink.

[0131] When using CA, one of the aggregated cells of the UE may be referred to as the Primary Cell (PCell). The PCell can be the serving cell to which the UE first connects in RRC connection establishment, re - establishment, and / or handover. The PCell can provide NAS mobility information and security inputs to the UE. The UE can have different PCells. In the downlink, the carrier corresponding to the PCell may be referred to as the Downlink Primary CC (DL PCC). In the uplink, the carrier corresponding to the PCell may be referred to as the Uplink Primary CC (UL PCC). The other aggregated cells of the UE may be referred to as Secondary Cells (SCells). In one embodiment, an SCell can be configured after the PCell is configured for the UE. For example, an SCell can be configured via the RRC connection re - configuration procedure. In the downlink, the carrier corresponding to the SCell may be referred to as the Downlink Secondary CC (DL SCC). In the uplink, the carrier corresponding to the SCell may be referred to as the Uplink Secondary CC (UL SCC).

[0132] The SCell configured for the UE can be activated and deactivated, for example, based on traffic and channel conditions. The deactivation of the SCell can mean that the PDCCH and PDSCH reception on the SCell is stopped, and the PUSCH, SRS, and CQI transmissions on the SCell are stopped. The configured SCell can be activated and deactivated using MAC CE with respect to Figure 4B. For example, the MAC CE can use a bitmap (e.g., 1 bit per SCell) to indicate which SCell (e.g., among a subset of the configured SCells) for the UE is activated or deactivated. The configured SCell can be deactivated in response to the expiration of an SCell deactivation timer (e.g., one SCell deactivation timer per SCell).

[0133] Downlink control information such as cell scheduling assignment and scheduling grant can be transmitted on the cell corresponding to the assignment and grant, known as self-scheduling. DCI for a cell can be transmitted on another cell known as cross-carrier scheduling. Uplink control information for an aggregation cell (e.g., HARQ acknowledgment responses and channel state feedback such as CQI, PMI, and / or RI) can be transmitted on the PUCCH of the PCell. If the number of aggregated downlink CCs is large, the PUCCH of the PCell may become overloaded. The cell may be divided into multiple PUCCH groups.

[0134] FIG. 10B shows an example of how an aggregation cell can be configured into one or more PUCCH groups. PUCCH group 1010 and PUCCH group 1050 may each include one or more downlink CCs. In the example of FIG. 10B, UCCH group 1010 includes three downlink CCs of PCell 1011, SCell 1012, and SCell 1013. PUCCH group 1050 includes three downlink CCs of PCell 1051, SCell 1052, and SCell 1053 in this example. One or more uplink CCs may be configured as PCell 1021, SCell 1022, and SCell 1023. One or more other uplink CCs may be configured as primary S cell (PSCell) 1061, SCell 1062, and SCell 1063. Uplink control information (UCI) related to the downlink CCs of PUCCH group 1010 shown as UCI 1031, UCI 1032, and UCI 1033 may be transmitted on the uplink of PCell 1021. Uplink control information (UCI) related to the downlink CCs of PUCCH group 1050 shown as UCI 1071, UCI 1072, and UCI 1073 may be transmitted on the uplink of PSCell 1061. In one example, if the aggregation cell depicted in FIG. 10B is not split into PUCCH group 1010 and PUCCH group 1050, a single uplink PCell and PCell for transmitting UCI related to the downlink CCs may be overloaded. By splitting the transmission of UCI between PCell 1021 and PSCell 1061, overload can be prevented.

[0135] A cell including a downlink carrier and an optional uplink carrier can be assigned a physical cell ID and a cell index. The physical cell ID or the cell index can identify the downlink carrier and / or the uplink carrier of the cell, depending on the context, e.g., where the physical cell ID is used. The physical cell ID can be determined using the synchronization signal transmitted on the downlink component carrier. The cell index can be determined using the RRC message. In the present disclosure, the physical cell ID may be referred to as the carrier ID. The cell index may be referred to as the carrier index. For example, when the present disclosure refers to the first physical cell ID for the first downlink carrier, the present disclosure can mean that the first physical cell ID is for the cell including the first downlink carrier. The same concept can be applied, for example, to the activation of a carrier. When the present disclosure indicates that the first carrier is activated, this specification can mean that the cell including the first carrier is activated.

[0136] In CA, the multi-carrier nature of the PHY can be exposed to the MAC. In one embodiment, the HARQ entity can operate on the serving cell. A transport block can be generated per allocation / grant per serving cell. The transport block and potential HARQ retransmissions of the transport block can be mapped to the serving cell.

[0137] In the downlink, a base station may transmit (e.g., unicast, multicast, and / or broadcast) one or more reference signals (RSs) to a UE (e.g., PSS, SSS, CSI-RS, DMRS, and / or PT-RS as shown in FIG. 5A). In the uplink, a UE can transmit one or more RSs to a base station (e.g., DMRS, PT-RS, and / or SRS as shown in FIG. 5B). The PSS and SSS are transmitted by the base station and used by the UE to synchronize the UE to the base station. The PSS and SSS may be provided within a synchronization signal (SS) / physical broadcast channel (PBCH) block that includes the PSS, SSS, and PBCH. The base station may periodically transmit bursts of SS / PBCH blocks.

[0138] FIG. 11A shows an example of the structure and location of an SS / PBCH block. A burst of SS / PBCH blocks may include one or more SS / PBCH blocks (e.g., four SS / PBCH blocks as shown in FIG. 11A). The burst may be transmitted periodically (e.g., every 2 frames or every 20 milliseconds). The burst may be restricted to a half-frame (e.g., a first half-frame having a duration of 5 milliseconds). FIG. 11A is an example, and it will be understood that these parameters (the number of SS / PBCH blocks per burst, the periodicity of the burst, the position of the burst within a frame) may be configured based on, for example, the carrier frequency of the cell in which the SS / PBCH block is transmitted, the numerology of the cell or the subcarrier spacing, network configuration (e.g., using RRC signaling), or any other appropriate factor. In one embodiment, a UE may assume a subcarrier spacing for an SS / PBCH block based on the carrier frequency being monitored, provided that this is not the case if the radio network has configured the UE to assume a different subcarrier spacing.

[0139] The SS / PBCH block may span one or more OFDM symbols within the time domain (e.g., four OFDM symbols as shown in the example of FIG. 11A), and may also span one or more subcarriers in the frequency domain (e.g., 240 consecutive subcarriers). The PSS, SSS, and PBCH may have a common center frequency. The PSS may be transmitted first, e.g., over one OFDM symbol and 127 subcarriers. The SSS may be transmitted after the PSS (e.g., in the next two symbols), and may span 1 OFDM symbol and 127 subcarriers. The PBCH may be transmitted after the PSS (e.g., over the next three OFDM symbols), and may span 240 subcarriers.

[0140] The position of the SS / PBCH block in the time and frequency domains may not be known to the UE (e.g., when the UE is searching for a cell). To find and select a cell, the UE may monitor the carrier of the PSS. For example, the UE may monitor the frequency position within the carrier. If the PSS is not found after a certain period (e.g., 20 milliseconds), the UE may search for the PSS at different frequency positions within the carrier as indicated by the synchronization raster. When the PSS is found at its position in the time and frequency domains, the UE may determine the positions of the SSS and PBCH respectively based on the known structure of the SS / PBCH block. The SS / PBCH block may be a cell-defined SS block (CD-SSB). In one embodiment, the primary cell may be associated with the CD-SSB. The CD-SSB may be placed on the synchronization raster. In one embodiment, cell selection / search and / or reselection may be based on the CD-SSB.

[0141] The SS / PBCH block can be used by a UE to determine one or more parameters of a cell. For example, the UE can determine the physical cell identifier (PCI) of a cell based on each of the sequences of the PSS and SSS. The UE can determine the position of the frame boundary of a cell based on the position of the SS / PBCH block. For example, the SS / PBCH block may indicate that it was transmitted according to a transmission pattern, and the SS / PBCH block in the transmission pattern is a known distance from the frame boundary.

[0142] The PBCH may use QPSK modulation and may use forward error correction (FEC). The FEC may use polar coding. One or more symbols spanned by the PBCH may carry one or more DMRSs for demodulation of the PBCH. The PBCH may include an indication of the current system frame number (SFN) of the cell and / or the SS / PBCH block timing index. These parameters may facilitate time synchronization of the UE to the base station. The PBCH may include the master information block (MIB) used to provide one or more parameters to the UE. The MIB can be used by the UE to find the remaining minimum system information (RMSI) associated with the cell. The RMSI may include the system information block type 1 (SIB1). The SIB1 may include information necessary for the UE to access the cell. The UE may use one or more parameters of the MIB to monitor the PDCCH, which can be used to schedule the PDSCH. The PDSCH may include the SIB1. The SIB1 may be decoded using the parameters provided in the MIB. The PBCH may indicate the absence of the SIB1. Based on the PBCH indicating the absence of the SIB1, the UE may indicate a frequency. The UE may search for the SS / PBCH block at the frequency indicated by the UE.

[0143] The UE can assume that one or more SS / PBCH blocks transmitted with the same SS / PBCH block index are quasi-co-located (QCL) (e.g., having the same / similar Doppler spread, Doppler shift, average gain, average delay, and / or spatial Rx parameters). The UE cannot assume that SS / PBCH blocks having different SS / PBCH block indexes are QCL for SS / PBCH block transmissions.

[0144] SS / PBCH blocks (e.g., blocks within a half-frame) can be transmitted in a spatial direction (e.g., using different beams across the cell coverage area). In one example, a first SS / PBCH block may be transmitted in a first spatial direction using a first beam, and a second SS / PBCH block may be transmitted in a second spatial direction using a second beam.

[0145] In one example, within the frequency span of a carrier, the base station can transmit multiple SS / PBCH blocks. In one example, the first PCI of the first SS / PBCH block of the multiple SS / PBCH blocks may be different from the second PCI of the second SS / PBCH block of the multiple SS / PBCH blocks. The PCI of SS / PBCH blocks transmitted at different frequency positions may be different or the same.

[0146] CSI-RS can be transmitted by a base station and used by a UE to obtain channel state information (CSI). The base station can configure the UE with one or more CSI-RSs for channel estimation or any other suitable purpose. The base station can configure the UE with one or more of the same / similar CSI-RSs. The UE can measure one or more CSI-RSs. The UE can estimate the downlink channel state and / or generate a CSI report based on the measurement of one or more downlink CSI-RSs. The UE can provide the CSI report to the base station. The base station can perform link adaptation using the feedback (e.g., the estimated downlink channel state) provided by the UE.

[0147] The base station can semi-statically configure the UE with one or more CSI-RS resource sets. The CSI-RS resources may be associated with positions and periodicities within the time and frequency domains. The base station can selectively activate and / or deactivate the CSI-RS resources. The base station can indicate to the UE that the CSI-RS resources within the CSI-RS resource set are activated and / or deactivated.

[0148] The base station can configure the UE to report CSI measurement values. The base station can configure the UE to provide CSI reports periodically, non-periodically, or semi-persistently. For periodic CSI reports, the UE can be configured with the timing and / or periodicity of multiple CSI reports. For non-periodic CSI reports, the base station can request a CSI report. For example, the base station can instruct the UE to measure the configured CSI-RS resources and provide a CSI report regarding the measurement values. For semi-persistent CSI reports, the base station can transmit periodic reports regularly and configure the UE to selectively activate or deactivate. The base station can configure the UE with CSI-RS resource sets and CSI reports using RRC signaling.

[0149] The CSI-RS configuration may include one or more parameters indicating, for example, up to 32 antenna ports. The UE can be configured to use the same OFDM symbol for the downlink CSI-RS and the control resource set (CORESET) when the downlink CSI-RS and the CORESET are spatially QCL and the resource elements associated with the downlink CSI-RS are outside the physical resource blocks (PRBs) configured for the CORESET. The UE can be configured to use the same OFDM symbol for the downlink CSI-RS and the SS / PBCH block when the downlink CSI-RS and the SS / PBCH block are spatially QCL and the resource elements associated with the downlink CSI-RS are outside the PRBs configured for the SS / PBCH block.

[0150] The downlink DMRS may be transmitted by the base station and can be used by the UE for channel estimation. For example, the downlink DMRS can be used for coherent demodulation of one or more downlink physical channels (e.g., PDSCH). The NR network may support one or more variable and / or configurable DMRS patterns for data demodulation. At least one downlink DMRS configuration can support a front-loaded DMRS pattern. The front-loaded DMRS can be mapped to one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). The base station can semi-statically configure the UE using the number (e.g., the maximum number) of front-loaded DMRS symbols of the PDSCH. The DMRS configuration may support one or more DMRS ports. For example, in the case of single-user MIMO, the DMRS configuration may support a maximum of eight orthogonal downlink DMRS ports per UE. In the case of multi-user MIMO, the DMRS configuration can support a maximum of four orthogonal downlink DMRS ports per UE. The radio network can support a common DMRS structure for downlink and uplink (e.g., for at least CP-OFDM). The DMRS position, DMRS pattern, and / or scrambling sequence may be the same or different. The base station can transmit the downlink DMRS and the corresponding PDSCH using the same precoding matrix. The UE can use one or more downlink DMRSs for coherent demodulation / channel estimation of the PDSCH.

[0151] In one embodiment, a transmitter (e.g., a base station) may use a precoder matrix for a part of the transmission bandwidth. For example, the transmitter may use a first precoder matrix for a first bandwidth and a second precoder matrix for a second bandwidth. The first precoder matrix and the second precoder matrix may be different based on the first bandwidth being different from the second bandwidth. The UE may assume that the same precoding matrix is used across a set of PRBs. The set of PRBs may be indicated as a precoding resource block group (PRG).

[0152] The PDSCH may include one or more layers. The UE may assume that at least one symbol with DMRS is present on one or more layers of the PDSCH. The upper layer may configure up to three DMRSs for the PDSCH.

[0153] Downlink PT-RS may be transmitted by the base station and can be used by the UE for phase noise compensation. Whether downlink PT-RS exists or not depends on the RRC configuration. The presence and / or pattern of downlink PT-RS can be indicated by a combination of RRC signaling and / or DCI, and can be configured on a UE-specific basis using its association with one or more parameters used for other purposes (e.g., modulation and coding scheme (MCS)). When configured, the dynamic presence of downlink PT-RS can be associated with one or more DCI parameters including at least MCS. The NR network can support multiple PT-RS densities defined in the time and / or frequency domain. The frequency domain density, if it exists, can be associated with at least one configuration of the scheduled bandwidth. The UE may assume the same precoding for DMRS ports and PT-RS ports. The number of PT-RS ports may be less than the number of DMRS ports within the scheduled resources. Downlink PT-RS can be restricted to the scheduled time / frequency period of the UE. Downlink PT-RS can be transmitted on symbols to facilitate phase tracking at the receiver.

[0154] The UE can transmit uplink DMRS to the base station for channel estimation. For example, the base station may use uplink DMRS for coherent demodulation of one or more uplink physical channels. For example, the UE may transmit uplink DMRS on PUSCH and / or PUCCH. The uplink DM-RS may span a frequency range similar to the frequency range associated with the corresponding physical channel. The base station can configure the UE with one or more uplink DMRS configurations. At least one DMRS configuration may support a front-loaded DMRS pattern. The front-loaded DMRS can be mapped to one or more OFDM symbols (e.g., one or two adjacent OFDM symbols). One or more uplink DMRS may be configured to be transmitted in one or more symbols of PUSCH and / or PUCCH. The base station can semi-statically configure the UE using the number (e.g., the maximum number) of front-loaded DMRS symbols for PUSCH and / or PUCCH that the UE can use to schedule single-symbol DMRS and / or double-symbol DMRS. The NR network may support a common DMRS structure for downlink and uplink (e.g., for cyclic prefix orthogonal frequency division multiplexing (CP-OFDM)), where the DMRS position, DMRS pattern, and / or DMRS scrambling sequence may be the same or different.

[0155] The PUSCH may include one or more layers, and the UE may transmit at least one symbol having DMRS existing on one or more layers of the PUSCH. In one embodiment, the upper layer may configure up to three DMRS for the PUSCH.

[0156] The uplink PT-RS (which can be used by the base station for phase tracking and / or phase noise compensation) may or may not exist depending on the UE's RRC configuration. The presence and / or pattern of the uplink PT-RS can be configured on a UE-specific basis by a combination of one or more parameters used for other purposes (e.g., Modulation and Coding Scheme (MCS)) that can be indicated by RRC signaling and / or DCI. When configured, the dynamic presence of the uplink PT-RS can be associated with one or more DCI parameters including at least the MCS. The radio network can support multiple uplink PT-RS densities defined in the time / frequency domain. The frequency domain density, if it exists, can be associated with at least one configuration of the scheduled bandwidth. The UE may assume the same precoding for the DMRS ports and the PT-RS ports. The number of PT-RS ports may be less than the number of DMRS ports within the scheduled resources. For example, the uplink PT-RS can be restricted to the UE's scheduled time / frequency period.

[0157] The SRS can be transmitted by the UE to the base station for channel state estimation in order to support uplink channel-dependent scheduling and / or link adaptation. The SRS transmitted by the UE can enable the base station to estimate the uplink channel state at one or more frequencies. The base station scheduler can use the estimated uplink channel state to allocate one or more resource blocks for uplink PUSCH transmission from the UE. The base station can semi-statically configure the UE using one or more SRS resource sets. In the case of an SRS resource set, the base station can configure the UE using one or more SRS resources. The SRS resource set applicability can be configured by higher layer (e.g., RRC) parameters. For example, when the higher layer parameter indicates beam management, the SRS resources within an SRS resource set (e.g., having the same / similar time domain behavior, periodicity, aperiodicity, and / or the same type) of one or more SRS resource sets can be transmitted instantaneously (e.g., simultaneously). The UE can transmit one or more SRS resources within the SRS resource set. The NR network can support aperiodic, periodic, and / or semi-persistent SRS transmissions. The UE may transmit SRS resources based on one or more trigger types, and the one or more trigger types may include higher layer signaling (e.g., RRC) and / or one or more DCI formats. In one embodiment, at least one DCI format can be used for the UE to select at least one of one or more configured SRS resource sets. SRS trigger type 0 can refer to SRS triggered based on higher layer signaling. SRS trigger type 1 can refer to SRS triggered based on one or more DCI formats. In one embodiment, when the PUSCH and SRS are transmitted in the same slot, the UE can be configured to transmit the SRS after the transmission of the PUSCH and the corresponding uplink DMRS.

[0158] The base station can semi-statically configure the UE using one or more SRS configuration parameters indicating at least one of the SRS resource configuration identifier, the number of SRS ports, the time-domain behavior of the SRS resource configuration (e.g., indication of periodic, semi-persistent, or aperiodic SRS), slot, mini-slot, and / or sub-frame level periodicity, the offset for periodic and / or aperiodic SRS resources, the number of OFDM symbols in the SRS resource, the starting OFDM symbol of the SRS resource, the SRS bandwidth, the frequency hopping bandwidth, the periodic shift, and / or the SRS sequence ID.

[0159] An antenna port is defined such that the channel over which a symbol on the antenna port is transmitted can be inferred from the channel over which another symbol on the same antenna port is transmitted. When a first symbol and a second symbol are transmitted on the same antenna port, the receiver can infer the channel (e.g., fade gain, multipath delay, and / or the like) for carrying the second symbol on the antenna port from the channel for carrying the first symbol on the antenna port. The first antenna port and the second antenna port may be called quasi-co-located (QCLed) if one or more large-scale characteristics of the channel over which the first symbol on the first antenna port is transmitted can be inferred from the channel over which the second symbol on the second antenna port is transmitted. The one or more large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and / or spatial receive (Rx) parameters.

[0160] In channels that use beamforming, beam management is required. Beam management may include beam measurement, beam selection, and beam indication. A beam may be associated with one or more reference signals. For example, a beam may be identified by one or more beamforming reference signals. The UE may perform downlink beam measurements based on downlink reference signals (e.g., Channel State Information Reference Signals (CSI-RS)) and generate a beam measurement report. The UE may perform downlink beam measurement procedures after the RRC connection is set up at the base station.

[0161] Figure 11B shows an example of a Channel State Information Reference Signal (CSI-RS) mapped in the time and frequency domains. The squares shown in Figure 11B may span resource blocks (RBs) within the cell bandwidth. The base station can transmit one or more RRC messages including CSI-RS resource configuration parameters indicating one or more CSI-RSs. One or more of the following parameters can be set by upper layer signaling (e.g., RRC and / or MAC signaling) for the CSI-RS resource configuration. CSI-RS resource configuration identity, number of CSI-RS ports, CSI-RS configuration (e.g., symbol and resource element (RE) positions within a subframe), CSI-RS subframe configuration (e.g., subframe position, offset, and radio frame periodicity), CSI-RS power parameter, CSI-RS sequence parameter, code division multiplexing (CDM) type parameter, frequency density, transmission beam, quasi co-location (QCL) parameter (e.g., QCL-scramblingidentity, crs-portscount, mbsfn-subframeconfiglist, csi-rs-configZPid, qcl-csi-rs-configNZPid), and / or other radio resource parameters.

[0162] The three beams shown in FIG. 11B can be configured for a UE with a UE-specific configuration. The three beams are shown in FIG. 11B (beam #1, beam #2, and beam #3), and more or fewer beams can be configured. Beam #1 can be allocated by CSI-RS1101 that can be transmitted on one or more subcarriers within the RB of the first symbol. Beam #2 can be allocated by CSI-RS1102 that can be transmitted on one or more subcarriers within the RB of the second symbol. Beam #3 can be allocated by CSI-RS1103 that can be transmitted on one or more subcarriers within the RB of the third symbol. By using frequency-division multiplexing (FDM), the base station can transmit another CSI-RS associated with the beam of another UE using other subcarriers within the same RB (e.g., those not used for transmitting CSI-RS1101). By using time-domain multiplexing (TDM), the beams used by the UE can be configured such that the symbols from the beams of other UEs are used by the beams of the UE.

[0163] The CSI-RS shown in FIG. 11B (e.g., CSI-RS 1101, 1102, 1103) is transmitted by a base station and can be used by a UE for one or more measurements. For example, the UE can measure the reference signal received power (RSRP) of the configured CSI-RS resources. The base station may configure the UE using a reporting configuration, and the UE may report the RSRP measurement value to the network (e.g., via one or more base stations) based on the reporting configuration. In one embodiment, the base station may determine one or more transmission configuration indication (TCI) states including some reference signals based on the reported measurement results. In one embodiment, the base station may indicate one or more TCI states to the UE (e.g., via RRC signaling, MAC CE, and / or DCI). The UE may receive downlink transmissions having a receive (Rx) beam determined based on one or more TCI states. In one embodiment, the UE may or may not have beam correspondence capabilities. If the UE has beam correspondence capabilities, the UE may determine the spatial domain filter of the transmit (Tx) beam based on the spatial domain filter of the corresponding Rx beam. If the UE does not have beam correspondence capabilities, the UE may execute an uplink beam selection procedure to determine the spatial domain filter of the Tx beam. The UE may execute an uplink beam selection procedure based on one or more sounding reference signal (SRS) resources configured for the UE by the base station. The base station may select and indicate an uplink beam for the UE based on the measurement values of one or more SRS resources transmitted by the UE.

[0164] In the beam management procedure, the UE may evaluate (e.g., measure) the channel quality of one or more beam pair links, the transmission beam transmitted by the base station, and the reception beam received by the UE. Based on the evaluation, the UE may transmit a beam measurement report indicating one or more beam pair quality parameters, including, for example, one or more beam identifications (e.g., beam index, reference signal index, or the like), RSRP, precoding matrix indicator (PMI), channel quality indicator (CQI), and / or rank indicator (RI).

[0165] Figure 12A shows examples of three downlink beam management procedures, P1, P2, and P3. Procedure P1 may enable UE measurements at the transmission (Tx) beam of a transmission reception point (TRP) (or multiple TRPs) to support the selection of one or more base station Tx beams and / or UE Rx beams (displayed as ellipses at the top and bottom rows of P1, respectively). Beamforming at the TRP may include a Tx beam sweep of a set of beams (as shown by the dashed arrows at the top row of P1 and P2, the ellipse is shown rotating counterclockwise). Beamforming at the UE may include an Rx beam sweep for a set of beams (as shown in the lower rows of P1 and P3, the ellipse rotates in the clockwise direction when indicated by the dashed arrow). Using procedure P2, UE measurements at the Tx beam of the TRP can be enabled. (As shown by the dashed arrow at the top row of P2, the ellipse is shown rotating counterclockwise). The UE and / or the base station may perform procedure P2 using a set of beams smaller than those used in procedure P1 or using beams narrower than the beams used in procedure P1. This may be referred to as beam refinement. The UE may perform procedure P3 for Rx beam determination by using the same Tx beam at the base station and sweeping the Rx beam at the UE.

[0166] Figure 12B shows examples of three uplink beam management procedures, U1, U2, and U3. Using procedure U1, for example, the base station may be enabled to perform measurements on the UE's Tx beam to support the selection of, for example, one or more UE Tx beams and / or base station Rx beams (shown as ellipses at the top and bottom of U1, respectively). Beamforming at the UE may include, for example, a Tx beam sweep from a set of beams. (Shown as an ellipse rotated clockwise as indicated by the dashed arrow below U1 and U3). Beamforming at the base station may include, for example, an Rx beam sweep from a set of beams. (Shown as if the ellipse is rotated counterclockwise as indicated by the dashed arrow at the top of U1 and U2). Using procedure U2, the base station may be enabled to adjust its Rx beam when the UE uses a fixed Tx beam. The UE and / or the base station may perform procedure U2 using a set of beams smaller than those used in procedure P1 or using beams narrower than the beams used in procedure P1. This may be referred to as beam refinement. The UE may perform procedure U3 to adjust its Tx beam when the base station uses a fixed Rx beam.

[0167] The UE may initiate a beam failure recovery (BFR) procedure based on the detection of a beam failure. The UE may transmit a BFR request (e.g., preamble, UCI, SR, MAC CE, and / or the like) based on the initiation of the BFR procedure. The UE may detect a beam failure based on a determination that the quality of the beam pair link of the associated control channel is unsatisfactory (e.g., having an error rate higher than an error rate threshold, a received signal power lower than a received signal power threshold, expiration of a timer, and / or the like).

[0168] The UE may measure the quality of the beam pair link using one or more reference signals (RS) including one or more SS / PBCH blocks, one or more CSI-RS resources, and / or one or more demodulation reference signals (DMRS). The quality of the beam pair link may be based on one or more of the block error rate (BLER), RSRP value, signal-to-interference plus noise ratio (SINR) value, reference signal received quality (RSRQ) value, and / or CSI value measured on the RS resource. The base station may indicate that the RS resource is quasi-co-located (QCL) with one or more DM-RS of a channel (e.g., control channel, shared data channel, and / or the like). The RS resource of the channel and one or more DMRS may be QCL when the channel characteristics (e.g., Doppler shift, Doppler spread, average delay, delay spread, spatial Rx parameters, fade, and / or the like) from the transmission to the UE via the RS resource are similar or identical to the channel characteristics from the transmission to the UE via the channel.

[0169] The network (e.g., gNB and / or ng-eNB of the network) and / or the UE may initiate a random access procedure. A UE in the RRC_IDLE state and / or a UE in the RRC_INACTIVE state may initiate a random access procedure to request connection setup to the network. The UE may initiate a random access procedure from the RRC_CONNECTED state. The UE may initiate a random access procedure to request uplink resources (e.g., for SR uplink transmission when there are no available PUCCH resources) and / or to obtain uplink timing (e.g., when the uplink synchronization state is not synchronized). The UE may initiate a random access procedure to request one or more system information blocks (SIBs) (e.g., other system information such as SIB2, SIB3, and / or the like). The UE may initiate a random access procedure for beam failure recovery. The network may initiate a random access procedure for handover and / or to establish time alignment for SCell addition.

[0170] Figure 13A shows a 4-step contention-based random access procedure. Before the start of the procedure, the base station may send a configuration message 1310 to the UE. Figure 13A includes the transmission of four messages: Msg1 1311, Msg2 1312, Msg3 1313, and Msg4 1314. Msg1 1311 may include a preamble (or random access preamble) and / or may be referred to as a preamble. Msg2 1312 may include a random access response (RAR) and / or may be referred to as a random access response (RAR).

[0171] The constitution message 1310 can be transmitted, for example, using one or more RRC messages. The one or more RRC messages may indicate one or more random access channel (RACH) parameters to the UE. The one or more RACH parameters may include at least one of general parameters (e.g., RACH-configGeneral) for one or more random access procedures, cell-specific parameters (e.g., RACH-ConfigCommon), and / or dedicated parameters (e.g., RACH-configDedicated). The base station can broadcast or multicast the one or more RRC messages to one or more UEs. The one or more RRC messages may be UE-specific (e.g., dedicated RRC messages transmitted to the UE in the RRC_CONNECTED state and / or the RRC_INACTIVE state). The UE may determine the time-frequency resources and / or uplink transmission power for the transmission of Msg1 1311 and / or Msg3 1313 based on the one or more RACH parameters. Based on the one or more RACH parameters, the UE may determine the reception timing and downlink channel for receiving Msg2 1312 and Msg4 1314.

[0172] One or more RACH parameters provided in the configuration message 1310 may indicate one or more physical RACH (PRACH) opportunities available for the transmission of Msg1 1311. The one or more PRACH opportunities may be pre-defined. One or more RACH parameters may indicate one or more available sets of one or more PRACH opportunities (e.g., prach-ConfigIndex). One or more RACH parameters may indicate the association between (a) one or more PRACH opportunities and (b) one or more reference signals. One or more RACH parameters may indicate the association between (a) one or more preambles and (b) one or more reference signals. The one or more reference signals may be SS / PBCH blocks and / or CSI-RS. For example, one or more RACH parameters may indicate the number of SS / PBCH blocks mapped to a PRACH opportunity and / or the number of preambles mapped to an SS / PBCH block.

[0173] The uplink transmission power of Msg1 1311 and / or Msg3 1313 may be determined using one or more RACH parameters provided in the configuration message 1310. For example, one or more RACH parameters may indicate a reference power for preamble transmission (e.g., a received target power and / or an initial power for preamble transmission). There may be one or more power offsets indicated by one or more RACH parameters. For example, one or more RACH parameters may indicate a power ramping step, a power offset between an SSB and a CSI-RS, a power offset between the transmission of Msg1 1311 and Msg3 1313, and / or a power offset value between preamble groups. One or more RACH parameters may indicate one or more thresholds for a UE to determine at least one reference signal (e.g., an SSB and / or a CSI-RS) and / or an uplink carrier (e.g., a normal uplink (NUL) carrier and / or a supplementary uplink (SUL) carrier).

[0174] Msg1 1311 may include one or more preamble transmissions (e.g., a preamble transmission and one or more preamble retransmissions). The RRC message may be used to constitute one or more preamble groups (e.g., group A and / or group B). The preamble group may include one or more preambles. The UE may determine the preamble group based on the path loss measurement and / or the size of Msg3 1313. The UE may measure the RSRP of one or more reference signals (e.g., SSB and / or CSI-RS) and determine at least one reference signal having an RSRP exceeding an RSRP threshold (e.g., rsrp-ThresholdSSB and / or rsrp-ThresholdCSI-RS). The UE may select at least one preamble associated with one or more reference signals and / or the selected preamble group if, for example, the association between one or more preambles and at least one reference signal is constituted by the RRC message.

[0175] The UE may determine the preamble based on one or more RACH parameters provided in the configuration message 1310. For example, the UE may determine the preamble based on path loss measurement, RSRP measurement, and / or the size of Msg3 1313. As another example, the one or more RACH parameters may indicate one or more thresholds for determining the preamble format, the maximum number of preamble transmissions, and / or one or more preamble groups (e.g., group A and group B). The base station may use the one or more RACH parameters to configure the UE in an association between one or more preambles and one or more reference signals (e.g., SSB and / or CSI-RS). When the association is configured, the UE may determine the preamble to include in Msg1 1311 based on the association. Msg1 1311 may be transmitted to the base station via one or more PRACH opportunities. The UE may use one or more reference signals (e.g., SSB and / or CSI-RS) for preamble selection and PRACH opportunity determination. One or more RACH parameters (e.g., ra-ssb-OccasionMskIndex and / or ra-OccasionList) may indicate the association between the PRACH opportunity and one or more reference signals.

[0176] If the UE does not receive a response after preamble transmission, it may perform preamble retransmission. The UE may increase the uplink transmission power for preamble retransmission. The UE may select the initial preamble transmission power based on path loss measurement and / or target received preamble power configured by the network. The UE may decide to retransmit the preamble and may ramp up the uplink transmission power. The UE may receive one or more RACH parameters (e.g., PREAMBLE_POWER_RAMPING_STEP) indicating the ramping step for preamble retransmission. The ramping step may be the amount of incremental increase in uplink transmission power for retransmission. If the UE determines the same reference signal (e.g., SSB and / or CSI-RS) as the previous preamble transmission, the UE may ramp up the uplink transmission power. The UE can count the number of preamble transmissions and / or retransmissions (e.g., PREAMBLE_TRANSMISSION_COUNTER). The UE may determine that the random access procedure has failed and completed if, for example, the number of preamble transmissions exceeds a threshold configured by one or more RACH parameters (e.g., preambleTransMax).

[0177] The Msg2 1312 received by the UE may contain an RAR. In some scenarios, the Msg2 1312 may contain multiple RARs corresponding to multiple UEs. The Msg2 1312 may be received after or in response to the transmission of Msg1 1311. The Msg2 1312 may be scheduled on the DL-SCH and indicated on the PDCCH using a random access radio network temporary identifier (RA-RNTI). The Msg2 1312 may indicate that Msg1 1311 has been received by the base station. The Msg2 1312 may include a timing alignment command that the UE may use to adjust the UE's transmission timing, Msg3 It may include scheduling permission for the transmission of 1313, and / or a temporary cell RNTI (TC-RNTI). After transmitting the preamble, the UE may start a time window (e.g., ra-ResponseWindow) for monitoring the PDCCH of Msg2 1312. The UE may determine when to start the time window based on the PRACH opportunity used by the UE to transmit the preamble. For example, the UE may start the time window after one or more symbols of the last symbol of the preamble (e.g., at the first PDCCH opportunity after the end of the preamble transmission). One or more symbols may be determined based on numerology. The PDCCH may be in a common search space (e.g., Type1-PDCCH common search space) configured by an RRC message. The UE may identify the RAR based on a radio network temporary identifier (RNTI). The RNTI may be used in response to one or more events that initiate a random access procedure. The UE may use a random access RNTI (RA-RNTI). The RA-RNTI may be associated with the PRACH opportunity used by the UE to transmit the preamble. For example, the UE may determine the RA-RNTI based on the OFDM symbol index, slot index, frequency domain index, and / or UL carrier indicator of the PRACH opportunity. Examples of RA-RNTI may be as follows. RA-RNTI = 1 + s_id + 14×t_id + 14×80×f_id + 14×80×8×ul_carrier_id Here, s_id may be the index of the first OFDM symbol of the PRACH opportunity (e.g., 0 ≦ s_id < 14), t_id may be the index of the first slot of the PRACH opportunity within the system frame (e.g., 0 ≦ t_id < 80), f_id may be the index of the PRACH opportunity in the frequency domain (e.g., 0 ≦ f_id < 8), and ul_carrier_id may be the UL carrier used for preamble transmission (e.g., 0 for NUL carrier and 1 for SUL carrier). In response to successful reception of Msg2 1312 (e.g., using the resources identified in Msg2 1312), the UE may transmit Msg3 1313. Msg3 1313 may be used, for example, for contention resolution in the contention-based random access procedure shown in Figure 13A. In some scenarios, multiple UEs may transmit the same preamble to the base station, and the base station may provide a RAR corresponding to the UE. If multiple UEs interpret the RAR as corresponding to themselves, a mismatch may occur. Contention resolution (e.g., the use of Msg3 1313 and Msg4 1314) may be used to increase the likelihood that a UE does not accidentally use the identity of another UE. To perform contention resolution, the UE may include a device identifier (e.g., if assigned, the C-RNTI, the TC-RNTI included in Msg2 1312, and / or any other appropriate identifier) in Msg3 1313.

[0178] Msg4 1314 may be received after or in response to the transmission of Msg3 1313. If the C-RNTI is included in Msg3 1313, the base station uses the C-RNTI to handle the UE on the PDCCH. If the UE's unique C-RNTI is detected on the PDCCH, it is determined that the random access procedure has been successfully completed. If the TC-RNTI is included in Msg3 1313 (e.g., if the UE is in the RRC_IDLE state or otherwise not connected to the base station), Msg4 1314 is received using the DL-SCH associated with the TC-RNTI. If the MAC PDU is successfully decoded and the MAC PDU matches the CCCH SDU transmitted (e.g., sent) in Msg3 1313 or otherwise contains the corresponding UE contention resolution identity EtOAc CE, the UE may determine that contention resolution has been successful and / or the UE may determine that the random access procedure has been successfully completed.

[0179] The UE can be composed of a supplementary uplink (SUL) carrier and a normal uplink (NUL) carrier. Initial access (e.g., random access procedure) can be supported on the uplink carrier. For example, the base station can configure the UE with two separate RACH configurations, i.e., one for the SUL carrier and the other for the NUL carrier. For random access within the cell configured with the SUL carrier, the network can indicate which carrier (NUL or SUL) to use. The UE can determine the SUL carrier, for example, when the measurement quality of one or more reference signals is lower than the broadcast threshold. The uplink transmission of the random access procedure (e.g., Msg1 1311 and / or Msg3 1313) can stay on the selected carrier. The UE can switch the uplink carrier during the random access procedure (e.g., between Msg1 1311 and Msg3 1313) in one or more cases. For example, the UE can determine and / or switch the uplink carrier of Msg1 1311 and / or Msg3 1313 based on the channel clear assessment (e.g., listen before talk).

[0180] Figure 13B shows a two-step contention-free random access procedure. Similar to the four-step contention-based random access procedure shown in Figure 13A, the base station can send a configuration message 1320 to the UE before the start of the procedure. The configuration message 1320 can be similar to the configuration message 1310 in some respects. Figure 13B includes the transmission of two messages, Msg1 1321 and Msg2 1322. Msg1 1321 and Msg2 1322 can be similar to Msg1 1311 and Msg2 1312 shown in Figure 13A respectively in some respects. As understood from Figures 13A and 13B, the contention-free random access procedure may not include messages similar to Msg3 1313 and / or Msg4 1314.

[0181] The random access procedure without contention shown in FIG. 13B may be initiated for beam failure recovery, other SI requests, SCell addition, and / or handover. For example, the base station may indicate or allocate to the UE the preamble used for Msg1 1321. The UE may receive an indication of the preamble (e.g., ra-PreambleIndex) from the base station via PDCCH and / or RRC.

[0182] After transmitting the preamble, the UE may start a time window (e.g., ra-ResponseWindow) to monitor the PDCCH of the RAR. In the case of a beam failure recovery request, the base station may configure the UE with a separate time window and / or a separate PDCCH within the search space indicated by the RRC message (e.g., recoverySearchSpaceId). The UE may monitor for PDCCH transmissions addressed to the Cell RNTI (C-RNTI) on the search space. In the random access procedure without contention shown in FIG. 13B, the UE may determine that the random access procedure has completed successfully after or in response to the transmission of Msg1 1321 and the reception of the corresponding Msg2 1322. The UE may determine that the random access procedure has completed successfully, for example, if the PDCCH transmission is addressed to the C-RNTI. The UE may determine that the random access procedure has completed successfully if, for example, the UE receives an RAR that includes a preamble identifier corresponding to the preamble transmitted by the UE, and / or if the RAR includes a MAC sub-PDU that includes the preamble identifier. The UE may determine the response as an indicator of confirmation for the SI request.

[0183] FIG. 13C shows another two-step random access procedure. Similar to the random access procedures shown in FIGS. 13A and 13B, the base station may be able to transmit a configuration message 1330 to the UE before the start of the procedure. The configuration message 1330 may be similar in some respects to the configuration message 1310 and / or the configuration message 1320. FIG. 13C includes the transmission of two messages, namely, Msg A 1331 and Msg B 1332.

[0184] Msg A 1331 can be transmitted by the UE in an uplink transmission. Msg A 1331 may include one or more transmissions of preamble 1341 and / or one or more transmissions of transport block 1342. The transport block 1342 may include content similar and / or equivalent to the content of Msg3 1313 shown in FIG. 13A. The transport block 1342 may include UCI (e.g., SR, HARQ ACK / NACK, and / or the like). The UE may receive Msg B 1332 after or in response to the transmission of Msg A 1331. Msg B 1332 may include content similar and / or equivalent to the content of Msg 2 1312 (e.g., RAR) shown in FIGS. 13A and 13B, and / or the content of Msg4 1314 shown in FIG. 13A.

[0185] The UE can initiate the two-step random access procedure of FIG. 13C for licensed spectrum and / or unlicensed spectrum. The UE may determine whether to initiate the two-step random access procedure based on one or more factors. The one or more factors may be the radio access technology in use (e.g., LTE, NR, and / or the like), whether the UE has a valid TA, cell size, the RRC state of the UE, the type of spectrum (e.g., licensed versus unlicensed), and / or any other appropriate factor.

[0186] The UE may determine the radio resources and / or uplink transmission power for the transport block 1342 included in the preamble 1341 and / or Msg A 1331 based on the two-step RACH parameters included in the configuration message 1330. The RACH parameters may indicate a modulation and coding scheme (MCS), time-frequency resources, and / or power control for the preamble 1341 and / or the transport block 1342. The time-frequency resources for the transmission of the preamble 1341 (e.g., PRACH) and the time-frequency resources for the transmission of the transport block 1342 (e.g., PUSCH) may be multiplexed using FDM, TDM, and / or CDM. The RACH parameters may enable the UE to determine the reception timing and downlink channel for the monitoring and / or reception of Msg B 1332.

[0187] The transport block 1342 may include data (e.g., delay-sensitive data), the UE identifier, security information, and / or device information (e.g., International Mobile Subscriber Identity (IMSI)). The base station may transmit Msg B 1332 as a response to Msg A 1331. Msg B 1332 may include at least one of a preamble identifier, a timing advance command, a power control command, an uplink grant (e.g., radio resource allocation and / or MCS), a UE identifier for contention resolution, and / or an RNTI (e.g., C-RNTI or TC-RNTI). The UE may determine that the two-step random access procedure is successfully completed when the preamble identifier of Msg B 1332 matches the preamble transmitted by the UE and / or the UE identifier of Msg B 1332 matches the UE identifier of Msg A 1331 (e.g., the transport block 1342).

[0188] The UE and the base station can exchange control signaling. The control signaling may be referred to as L1 / L2 control signaling and may originate from the PHY layer (e.g., layer 1) and / or the MAC layer (e.g., layer 2). The control signaling may include downlink control signaling transmitted from the base station to the UE and / or uplink control signaling transmitted from the UE to the base station.

[0189] The downlink control signaling may include downlink scheduling assignments, uplink scheduling grants indicating uplink radio resources and / or transport formats, slot format information, preemption indication, power control commands, and / or any other suitable signaling. The UE may receive the downlink control signaling in the payload transmitted by the base station on the physical downlink control channel (PDCCH). The payload transmitted on the PDCCH may be referred to as downlink control information (DCI). In some scenarios, the PDCCH may be a group common PDCCH (GC-PDCCH) common to a group of UEs.

[0190] The base station may attach one or more cyclic redundancy check (CRC) parity bits to the DCI to facilitate detection of transmission errors. If the DCI is intended for a UE (or a group of UEs), the base station may scramble the CRC parity bits with the identifier of the UE (or the identifier of the group of UEs). Scrambling the CRC parity bits with the identifier may include modulo-2 addition (or exclusive OR operation) of the identifier value and the CRC parity bits. The identifier may include a 16-bit value of a radio network temporary identifier (RNTI).

[0191] The DCI can be used for different purposes. The purpose can be indicated by the type of RNTI used to scramble the CRC parity bits. For example, DCI having CRC parity bits scrambled with a paging RNTI (P-RNTI) can indicate paging information and / or system information change notification. The P-RNTI can be pre-defined as "FFFE" in hexadecimal. DCI having CRC parity bits scrambled with a system information RNTI (SI-RNTI) can indicate the broadcast transmission of system information. The SI-RNTI can be pre-defined as "FFFE" in hexadecimal. DCI having CRC parity bits scrambled with a random access RNTI (RA-RNTI) can indicate a random access response (RAR). DCI having CRC parity bits scrambled with a cell RNTI (C-RNTI) can indicate the unicast transmission of a dynamic schedule and / or the trigger for random access of the PDCCH order. DCI having CRC parity bits scrambled with a temporary cell RNTI (TC-RNTI) can indicate contention resolution (e.g., Msg3 similar to Msg3 1313 shown in FIG. 13A). The encoding of other RNTIs configured by the base station for the UE includes Configured Scheduling RNTI (CS-RNTI), Transmit Power Control-PUCCH RNTI (TPC-PUCCH-RNTI), Transmit Power Control-PUSCH RNTI (TPC-PUSCH-RNTI), Transmit Power Control-SRS RNTI (TPC-SRS-RNTI), Interruption RNTI (INT-RNTI), Slot Format Indication RNTI (SFI-RNTI), Semi-Persistent CSI RNTI (SP-CSI-RNTI), Modulation and Coding Scheme Cell RNTI (MCS-C-RNTI), and / or the like.

[0192] Depending on the purpose and / or content of the DCI, the base station may transmit DCI in one or more DCI formats. For example, DCI format 0_0 can be used for scheduling PUSCH within a cell. DCI format 0_0 can be a fallback DCI format (e.g., having a compact DCI payload). DCI format 0_1 can be used for scheduling PUSCH within a cell (e.g., having more DCI payload than DCI format 0_0). DCI format 1_0 can be used for scheduling PDSCH within a cell. DCI format 1_0 can be a fallback DCI format (e.g., having a compact DCI payload). DCI format 1_1 can be used for scheduling PDSCH within a cell (e.g., having more DCI payload than DCI format 1_0). DCI format 2_0 can be used to provide slot format indication to a group of UEs. DCI format 2_1 can be used to notify a group of UEs of physical resource blocks and / or OFDM symbols that are assumed not to be intended for transmission to the UEs. DCI format 2_2 can be used for transmitting transmit power control (TPC) commands for PUCCH or PUSCH. DCI format 2_3 can be used for transmitting a group of TPC commands for SRS transmission by one or more UEs. New feature DCI formats may be defined in future releases. DCI formats may have different DCI sizes or share the same DCI size.

[0193] After scrambling the DCI with the RNTI, the base station may process the DCI using channel coding (e.g., polar coding), rate matching, scrambling, and / or QPSK modulation. The base station may map the encoded and modulated DCI onto resource elements used and / or configured for the PDCCH. Based on the payload size of the DCI and / or the coverage of the base station, the base station may transmit the DCI via a PDCCH that occupies several consecutive control channel elements (CCEs). The number of consecutive CCEs (referred to as the aggregation level) may be 1, 2, 4, 8, 16, and / or any other appropriate number. A CCE may include a number of resource element groups (REGs) (e.g., 6). A REG may include resource blocks within an OFDM symbol. The mapping of the encoded and modulated DCI onto the resource elements may be based on the mapping of the CCEs and REGs (e.g., CCE-to-REG mapping).

[0194] Figure 14A shows an example of a CORESET configuration for a bandwidth part. The base station may transmit the DCI via a PDCCH on one or more control resource sets (CORESETs). A CORESET may include time-frequency resources on which the UE attempts to decode the DCI using one or more search spaces. The base station may configure the CORESET within the time-frequency domain. In the example of Figure 14A, a first CORESET 1401 and a second CORESET 1402 occur in the first symbol within a slot. The first CORESET 1401 overlaps with the second CORESET 1402 in the frequency domain. A third CORESET 1403 occurs in the third symbol within the slot. A fourth CORESET 1404 occurs in the seventh symbol of the slot. A CORESET may have a different number of resource blocks in the frequency domain.

[0195] FIG. 14B shows an example of CCE-to-REG mapping for DCI transmission on CORESET and PDCCH processing. The CCE-to-REG mapping can be an interleaved mapping (e.g., for the purpose of providing frequency diversity) or a non-interleaved mapping (e.g., for the purpose of facilitating interference coordination and / or frequency selective transmission of control channels). The base station may perform different or the same CCE-to-REG mapping on different CORESETs. The CORESET may be associated with the CCE-to-REG mapping by RRC configuration. The CORESET may be configured with antenna port quasi-co-location (QCL) parameters. The QCL parameters of the antenna port may indicate the QCL information of the demodulation reference signal (DMRS) for PDCCH reception within the CORESET.

[0196] The base station can transmit an RRC message to the UE that includes the configuration parameters of one or more CORESETs and one or more search space sets. The configuration parameters may indicate the association between the search space set and the CORESET. The search space set may include a set of PDCCH candidates formed by CCEs at a given aggregation level. The configuration parameters may indicate, for each aggregation level, the number of PDCCH candidates to be monitored, the PDCCH monitoring periodicity and pattern, one or more DCI formats to be monitored by the UE, and / or whether the search space set is a common search space set or a UE-specific search space set. The set of CCEs within the common search space set may be predefined and known to the UE. The set of CCEs within the UE-specific search space set may be configured based on the identity of the UE (e.g., C-RNTI).

[0197] As shown in FIG. 14B, the UE may determine the time-frequency resources of the CORESET based on the RRC message. The UE may determine the CCE-to-REG mapping (e.g., interleaved or non-interleaved, and / or mapping parameters) for the CORESET based on the configuration parameters of the CORESET. The UE may determine the number of search space sets (e.g., up to 10) configured on the CORESET based on the RRC message. The UE may monitor a set of PDCCH candidates according to the configuration parameters of the search space set. The UE may monitor a set of PDCCH candidates within one or more CORESETs to detect one or more DCIs. The monitoring may include decoding one or more PDCCH candidates of the set of PDCCH candidates according to the monitored DCI format. The monitoring may include decoding the DCI content of one or more PDCCH candidates having possible (or configured) PDCCH positions, possible (or configured) PDCCH formats (e.g., the number of CCEs in the common search space, the number of PDCCH candidates, and / or the number of PDCCH candidates in the UE-specific search space), and possible (or configured) DCI formats. The decoding may be referred to as blind decoding. The UE may determine a valid DCI for the UE in response to a CRC check (e.g., the scrambling bits for the CRC parity bits of the DCI that match the RNTI value). The UE may process the information contained in the DCI (e.g., scheduling assignment, uplink grant, power control, slot format indication, downlink preemption, and / or the like).

[0198] The UE may transmit uplink control signaling (e.g., uplink control information (UCI)) to the base station. The uplink control signaling may include a hybrid automatic repeat request (HARQ) acknowledgment response for the received DL-SCH transport block. The UE may transmit the HARQ acknowledgment response after receiving the DL-SCH transport block. The uplink control signaling may include channel state information (CSI) indicating the channel quality of the physical downlink channel. The UE may transmit the CSI to the base station. The base station may determine transmission format parameters for downlink transmission (e.g., including multi-antenna and beamforming schemes) based on the received CSI. The uplink control signaling may include a scheduling request (SR). The UE may transmit an SR indicating that uplink data is available for transmission to the base station. The UE may transmit UCI (e.g., HARQ acknowledgment (HARQ-ACK), CSI report, SR, etc.) via the physical uplink control channel (PUCCH) or the physical uplink shared channel (PUSCH). The UE may transmit uplink control signaling via the PUCCH using one of several PUCCH formats.

[0199] There can be five PUCCH formats, and the UE can determine the PUCCH format based on the size of the UCI (e.g., the number of uplink symbols for UCI transmission and the number of UCI bits). PUCCH format 0 may have a length of one or two OFDM symbols and may contain 2 or fewer bits. The UE can use PUCCH format 0 to transmit the UCI on a PUCCH resource when the transmission exceeds one or two symbols and the number of HARQ-ACK information bits (HARQ-ACK / SR bits) with positive or negative SR is one or two. PUCCH format 1 may occupy a number between 4 and 14 OFDM symbols and may contain 2 or fewer bits. The UE can use PUCCH format 1 when the transmission is four or more symbols and the number of HARQ-ACK / SR bits is one or two. PUCCH format 2 may occupy one or two OFDM symbols and may contain more than 2 bits. The UE can use PUCCH format 2 when the transmission exceeds one or two symbols and the number of UCI bits is two or more. PUCCH format 3 may occupy a number between 4 and 14 OFDM symbols and may contain more than 2 bits. The UE can use PUCCH format 3 when the transmission is four or more symbols, the number of UCI bits is two or more, and the PUCCH resource does not include an orthogonal cover code. PUCCH format 4 may occupy a number between 4 and 14 OFDM symbols and may contain more than 2 bits. The UE can use PUCCH format 4 when the transmission is four or more symbols, the number of UCI bits is two or more, and the PUCCH resource includes an orthogonal cover code.

[0200] The base station can transmit the configuration parameters of a plurality of PUCCH resource sets to the UE using, for example, RRC messages. A plurality of PUCCH resource sets (e.g., up to four sets) can be configured on the uplink BWP of the cell. A PUCCH resource set can be composed of a PUCCH resource set index, a plurality of PUCCH resources identified by a PUCCH resource identifier (e.g., pucch-Resourceid), and / or the number (e.g., the maximum number) of UCI information bits that the UE can use to transmit using one of the plurality of PUCCH resources within the PUCCH resource set. When composed of a plurality of PUCCH resource sets, the UE can select one of the plurality of PUCCH resource sets based on the total bit length of the UCI information bits (e.g., HARQ-ACK, SR, and / or CSI). When the total bit length of the UCI information bits is 2 or less, the UE can select the first PUCCH resource set whose PUCCH resource set index is equal to "0". When the total bit length of the UCI information bits is greater than 2 and less than or equal to a first configured value, the UE can select a second PUCCH resource set having a PUCCH resource set index equal to "1". When the total bit length of the UCI information bits is greater than the first configured value and less than or equal to a second configured value, the UE can select a third PUCCH resource set having a PUCCH resource set index equal to "2". When the total bit length of the UCI information bits is greater than the second configured value and less than or equal to a third value (e.g., 1406), the UE can select a fourth PUCCH resource set having a PUCCH resource set index equal to "3".

[0201] After determining a PUCCH resource set from a plurality of PUCCH resource sets, the UE may determine a PUCCH resource from the PUCCH resource set for UCI (HARQ-ACK, CSI, and / or SR) transmission. The UE may determine the PUCCH resource based on a PUCCH resource indicator in DCI received on the PDCCH (e.g., DCI format 1_0 or DCI format 1_1). The 3-bit PUCCH resource indicator of the DCI may indicate one of eight PUCCH resources within the PUCCH resource set. Based on the PUCCH resource indicator, the UE may transmit UCI (HARQ-ACK, CSI, and / or SR) using the PUCCH resource indicated by the PUCCH resource indicator in the DCI.

[0202] FIG. 15 shows an example of a wireless device 1502 communicating with a base station 1504 according to an embodiment of the present disclosure. The wireless device 1502 and the base station 1504 may be part of a mobile communication network such as the mobile communication network 100 shown in FIG. 1A, the mobile communication network 150 shown in FIG. 1B, or other communication networks. Only one wireless device 1502 and one base station 1504 are shown in FIG. 15. However, it will be understood that the mobile communication network may include a plurality of UEs and / or a plurality of base stations having the same or similar configuration as that shown in FIG. 15.

[0203] The base station 1504 may connect the wireless device 1502 to a core network (not shown) via wireless communication on an air interface (or wireless interface) 1506. The communication direction from the base station 1504 to the wireless device 1502 on the air interface 1506 is known as the downlink, and the communication direction from the wireless device 1502 to the base station 1504 on the air interface is known as the uplink. Downlink transmission may be separated from uplink transmission using FDD, TDD, and / or some combination of two duplexing techniques.

[0204] In the downlink, data transmitted from base station 1504 to wireless device 1502 can be provided to the processing system 1508 of base station 1504. The data can be provided to the processing system 1508, for example, by a core network. In the uplink, data transmitted from wireless device 1502 to base station 1504 can be provided to the processing system 1518 of wireless device 1502. The processing system 1508 and the processing system 1518 can implement layer 3 and layer 2 OSI functions to process data for transmission. Layer 2 can include, for example, an SDAP layer, a PDCP layer, an RLC layer, and a MAC layer with respect to FIGS. 2A, 2B, 3, and 4A. Layer 3 can include an RRC layer with respect to FIG. 2B.

[0205] After being processed by the processing system 1508, data transmitted to wireless device 1502 can be provided to the transmission processing system 1510 of base station 1504. Similarly, after being processed by the processing system 1518, data transmitted to base station 1504 can be provided to the transmission processing system 1520 of wireless device 1502. The transmission processing system 1510 and the transmission processing system 1520 can implement layer 1 OSI functions. Layer 1 can include a PHY layer with respect to FIGS. 2A, 2B, 3, and 4A. For transmission processing, the PHY layer can perform, for example, forward error correction coding of a transport channel, interleaving, rate matching, mapping of the transport channel to a physical channel, modulation of the physical channel, multiple-input multiple-output (MIMO) or multi-antenna processing, and / or the like.

[0206] At base station 1504, reception processing system 1512 can receive uplink transmissions from wireless device 1502. At wireless device 1502, reception processing system 1522 can receive downlink transmissions from base station 1504. Reception processing system 1512 and reception processing system 1522 can implement the OSI functions of layer 1. Layer 1 can include a PHY layer with respect to FIGS. 2A, 2B, 3, and 4A. For reception processing, the PHY layer can perform, for example, error detection, forward error correction decoding, deinterleaving, demapping of transport channels to physical channels, demodulation of physical channels, MIMO or multi-antenna processing, and / or the like.

[0207] As shown in FIG. 15, wireless device 1502 and base station 1504 can include a plurality of antennas. The plurality of antennas can be used to implement one or more MIMO or multi-antenna techniques such as spatial multiplexing (e.g., single-user MIMO or multi-user MIMO), transmit / receive diversity, and / or beamforming. In other embodiments, wireless device 1502 and / or base station 1504 can have a single antenna.

[0208] Processing system 1508 and processing system 1518 may each be associated with memory 1514 and memory 1524. Memory 1514 and memory 1524 (e.g., one or more non-transitory computer-readable media) can store computer program instructions or code that can be executed by processing system 1508 and / or processing system 1518 to perform one or more of the functions discussed in this application. Although not shown in FIG. 15, transmission processing system 1510, transmission processing system 1520, reception processing system 1512, and / or reception processing system 1522 can be coupled to a memory (e.g., one or more non-transitory computer-readable media) that stores computer program instructions or code that can be executed to perform one or more of their respective functions.

[0209] Processing system 1508 and / or processing system 1518 may include one or more controllers and / or one or more processors. The one or more controllers and / or the one or more processors may include, for example, general-purpose processors, digital signal processors (DSPs), microcontrollers, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs) and / or other programmable logic devices, discrete gates and / or transistor logic, discrete hardware components, on-board units, or any combination thereof. Processing system 1508 and / or processing system 1518 may perform at least one of signal encoding / processing, data processing, power control, input / output processing, and / or any other function that may enable wireless device 1502 and base station 1504 to operate in a wireless environment.

[0210] Processing system 1508 and / or processing system 1518 may each be connected to one or more peripheral devices 1516 and one or more peripheral devices 1526. The one or more peripheral devices 1516 and the one or more peripheral devices 1526 may include software and / or hardware that provide features and / or functions, such as speakers, microphones, keypads, display devices, touch pads, power supplies, satellite transceivers, universal serial bus (USB) ports, hands-free headsets, frequency modulation (FM) radio units, media players, Internet browsers, electronic control units (e.g., for vehicles), and / or one or more sensors (e.g., accelerometers, gyroscopes, temperature sensors, radar sensors, lidar sensors, ultrasonic sensors, optical sensors, cameras, and / or the like). Processing system 1508 and / or processing system 1518 may receive user input data from the one or more peripheral devices 1516 and / or the one or more peripheral devices 1526 and / or provide user output data. The processing system 1518 within the wireless device 1502 may be configured to receive power from a power source and / or distribute power to other components within the wireless device 1502. The power source may include one or more power sources, such as batteries, solar cells, fuel cells, or any combination thereof. Processing system 1508 and / or processing system 1518 may each be connected to a GPS chipset 1517 and a GPS chipset 1527. The GPS chipset 1517 and the GPS chipset 1527 may each be configured to provide geographical location information of the wireless device 1502 and the base station 1504.

[0211] FIG. 16A shows an exemplary structure for uplink transmission. The baseband signal representative of the physical uplink shared channel can perform one or more functions. These one or more functions can include at least one of scrambling, modulation of scrambling bits to generate complex-valued symbols, mapping of the complex-valued modulated symbols onto one or several transmission layers, transform precoding to generate complex-valued symbols, precoding of the complex-valued symbols, mapping of the precoded complex-valued symbols to resource elements, generation of a complex-valued time-domain single-carrier frequency-division multiple access (SC-FDMA) or CP-OFDM signal to an antenna port, and / or the like. In one embodiment, when transform precoding is enabled, an SC-FDMA signal for uplink transmission can be generated. In one embodiment, when transform precoding is not enabled, a CP-OFDM signal for uplink transmission can be generated by FIG. 16A. These functions are shown by way of example, and it is expected that other mechanisms can be implemented in various embodiments.

[0212] FIG. 16B shows an exemplary structure for modulation of the baseband signal to a carrier frequency and upconversion. The baseband signal can be a complex-valued SC-FDMA or CP-OFDM baseband signal and / or a complex-valued physical random access channel (PRACH) baseband signal for an antenna port. Filtering can be used before transmission.

[0213] Figure 16C shows an exemplary structure of downlink transmission. A baseband signal representing a physical downlink channel can perform one or more functions. These one or more functions can include scrambling of the encoded bits in the codeword to be transmitted on the physical channel, modulation of the scrambled bits to generate complex-valued modulation symbols, mapping of the complex-valued modulation symbols onto one or several transmission layers, precoding of the complex-valued modulation symbols on the layer for transmission on the antenna port, mapping of the complex-valued modulation symbols of the antenna port onto resource elements, generation of the complex-valued time-domain OFDM signal for each antenna port, and / or the like. These functions are shown by way of example, and it is expected that other mechanisms can be implemented in various embodiments.

[0214] Figure 16D shows another exemplary structure for modulation and upconversion of the baseband signal to the carrier frequency. The baseband signal can be a complex-valued OFDM baseband signal for the antenna port. Filtering can be used before transmission.

[0215] The wireless device can receive from the base station one or more messages (e.g., RRC messages) including configuration parameters of a plurality of cells (e.g., primary cell, secondary cell). The wireless device can communicate with at least one base station (e.g., two or more base stations for dual connectivity) via a plurality of cells. One or more messages (e.g., as part of the configuration parameters) may include parameters of the physical, MAC, RLC, PCDP, SDAP, RRC layers for configuring the wireless device. For example, the configuration parameters may include parameters for configuring physical layer and MAC layer channels, bearers, etc. For example, the configuration parameters may include parameters indicating values of timers for the physical layer, MAC layer, RLC layer, PCDP layer, SDAP layer, RRC layer, and / or communication channels.

[0216] When the timer is started, execution begins and can continue until stopped or until expiration. The timer can be started when not running or restarted when running. The timer may be associated with a value (e.g., the timer may start or resume from a certain value, or start from zero and expire when a value is reached). The duration of the timer cannot be updated (e.g., by BWP switching) until the timer stops or expires. Timers can be used to measure the duration / window of a process. When this specification refers to implementations and procedures related to one or more timers, it will be understood that there are multiple ways to implement one or more timers. For example, it will be understood that one or more of the multiple ways to implement a timer can be used to measure the duration / window of a procedure. For example, a random access response window timer can be used to measure the window time for receiving a random access response. In one embodiment, instead of starting and expiring a random access response window timer, the time difference between two timestamps can be used. When the timer is resumed, the process for measuring the time window can be resumed. Other exemplary implementations can be provided to resume the measurement of the time window.

[0217] Figure 17 shows an example of device-to-device (D2D) communication where there is direct communication between wireless devices. In one embodiment, D2D communication may be performed via a sidelink (SL). Wireless devices may exchange sidelink communication via a sidelink interface (e.g., a PC5 interface). The sidelink is different from the uplink (where a wireless device communicates with a base station) and the downlink (where a base station communicates with a wireless device). Wireless devices and base stations may exchange uplink and / or downlink communication via a user plane interface (e.g., a Uu interface).

[0218] As shown in the figure, wireless device #1 and wireless device #2 can be within the coverage area of base station #1. For example, both wireless device #1 and wireless device #2 can communicate with base station #1 via the Uu interface. Wireless device #3 can be within the coverage area of base station #2. Base station #1 and base station #2 may share a network and jointly provide a network coverage area. Wireless device #4 and wireless device #5 can be outside the network coverage area.

[0219] In-coverage D2D communication may be performed when two wireless devices share a network coverage area. Both wireless device #1 and wireless device #2 are within the coverage area of base station #1. Therefore, they can perform in-coverage in-cell D2D communication labeled as sidelink A. Wireless device #2 and wireless device #3 are within the coverage areas of different base stations but share the same network coverage area. Therefore, they can perform in-coverage in-cell D2D communication labeled as sidelink B. Partial-coverage D2D communication can be performed when one wireless device is within the network coverage area and the other wireless device is outside the network coverage area. Wireless device #3 and wireless device #4 can perform partial-coverage D2D communication labeled as sidelink C. Out-of-coverage D2D communication can be performed when both wireless devices are outside the network coverage area. Wireless device #4 and wireless device #5 can perform out-of-coverage D2D communication labeled as sidelink D.

[0220] Sidelink communication can be configured using physical channels, such as the Physical Sidelink Broadcast Channel (PSBCH), Physical Sidelink Feedback Channel (PSFCH), Physical Sidelink Discovery Channel (PSDCH), Physical Sidelink Control Channel (PSCCH), and / or Physical Sidelink Shared Channel (PSSCH). The PSBCH can be used by a first wireless device to transmit broadcast information to a second wireless device. The PSBCH may be similar to the PBCH in some respects. The broadcast information may include, for example, slot format indication, resource pool information, sidelink system frame number, or any other suitable broadcast information. The PSFCH can be used by a first wireless device to transmit feedback information to a second wireless device. The feedback information may include, for example, HARQ feedback information. The PSDCH can be used by a first wireless device to transmit discovery information to a second wireless device. The discovery information can be used by a wireless device to signal its presence and / or service availability to other wireless devices within its area. The PSCCH can be used by a first wireless device to transmit sidelink control information (SCI) to a second wireless device. The PSCCH may be similar to the PDCCH and / or PUCCH in some respects. The control information may include, for example, time / frequency resource allocation information (RB size, number of retransmissions, etc.), demodulation-related information (DMRS, MCS, RV, etc.), identification information of the transmitting and / or receiving wireless device, process identifier (such as HARQ), or any other suitable control information. The PSCCH can be used to allocate, prioritize, and / or reserve sidelink resources for sidelink transmission. The PSSCH can be used by a first wireless device to transmit and / or relay data and / or network information to a second wireless device. The PSSCH may be similar to the PDSCH and / or PUSCH in some respects. Each of the sidelink channels may be associated with one or more demodulation reference signals.The sidelink operation can establish the timing of the sidelink operation by using sidelink synchronization signals. A wireless device configured for sidelink operation can transmit sidelink synchronization signals, for example, by using PSBCH. The sidelink synchronization signals can include a primary sidelink synchronization signal (PSSS) and a secondary sidelink synchronization signal (SSSS).

[0221] The sidelink resources can be configured for the wireless device in any suitable manner. The wireless device may be preconfigured for sidelink, for example, preconfigured with sidelink resource information. Additionally or alternatively, the network can broadcast system information related to a resource pool for sidelink. Additionally or alternatively, the network can configure a specific wireless device with a dedicated sidelink configuration. The configuration can identify sidelink resources used for sidelink operation (e.g., configuring a combination of sidelink bands).

[0222] The wireless device can operate in different modes, for example, a support mode (which may be called mode 1) or an autonomous mode (which may be called mode 2). The mode selection may be based on the coverage status of the wireless device, the radio resource control status of the wireless device, information and / or commands from the network, and / or any other suitable factors. For example, if the wireless device is idle or inactive, or if the wireless device is outside the network coverage area, the wireless device may be selected to operate in the autonomous mode. For example, if the wireless device is in a connected mode (e.g., connected to a base station), the wireless device may be selected to operate in the support mode (or commanded to operate by the base station). For example, the network (e.g., a base station) can instruct the connected wireless device to operate in a specific mode.

[0223] In the assistance mode, a wireless device may request scheduling from the network. For example, the wireless device may send a scheduling request to the network, and the network may allocate sidelink resources to the wireless device. The assistance mode may also be referred to as a network assistance mode, a gNB assistance mode, or a base station assistance mode. In the autonomous mode, the wireless device selects sidelink resources based on measurements within one or more resource pools (e.g., pre-configured or network-allocated resource pools), and the sidelink resource selection may be made by other wireless devices and / or the use of sidelink resources by other wireless devices may be selected.

[0224] To select sidelink resources, the wireless device may observe a sensing window and a selection window. During the sensing window, the wireless device may use the sidelink resource pool to observe the SCI transmitted by other wireless devices. The SCI may identify resources that may be used and / or reserved for sidelink transmissions. Based on the resources identified by the SCI, the wireless device may select resources within the selection window (e.g., resources different from those identified by the SCI). The wireless device may transmit using the selected sidelink resources.

[0225] FIG. 18 shows an example of a resource pool for sidelink operation. A wireless device may operate using one or more sidelink cells. A sidelink cell may include one or more resource pools. Each resource pool may be configured to operate according to a specific mode (e.g., assisted or autonomous). The resource pool may be divided into resource units. In the frequency domain, each resource unit may include one or more resource blocks, which may be referred to as subchannels, for example. In the time domain, each resource unit may include one or more slots, one or more subframes, and / or one or more OFDM symbols, for example. The resource pool may be continuous or discontinuous in the frequency domain and / or the time domain (e.g., including continuous resource units or discontinuous resource units). The resource pool may be divided into repeating resource pool portions. The resource pool may be shared among one or more wireless devices. Each wireless device may attempt to transmit using different resource units, for example, to avoid collisions.

[0226] The sidelink resource pool may be arranged in any suitable manner. In the figure, an exemplary resource pool is discontinuous in the time domain and limited to a single sidelink BWP. In an example of a resource pool, the frequency resources are divided into Nf resource units per unit time and numbered from zero to Nf-1. An exemplary resource pool may include a plurality of portions (discontinuous in this example) that are repeated every k units of time. In this figure, the time resources are numbered n, n+1,..., n+k, n+k+1,....

[0227] A wireless device may select one or more resource units from a resource pool for transmission. In an exemplary resource pool, the wireless device selects a resource unit (n,0) for sidelink transmission. The wireless device may further select periodic resource units in a later part of the resource pool, such as resource unit (n+k,0), resource unit (n+2k,0), resource unit (n+3k,0), etc. The selection may be based on a determination, for example, that communication using resource unit (n,0) does not collide (or has a low probability of colliding) with sidelink transmissions of wireless devices sharing the sidelink resource pool. The determination may be based on, for example, the behavior of other wireless devices sharing the resource pool. For example, if no sidelink transmission is detected at resource unit (n-k,0), the wireless device may select resource unit (n,0), resource (n+k,0), etc. For example, if a sidelink transmission from another wireless device is detected at resource unit (n-k,1), the wireless device may avoid selecting resource units such as (n,1), resource (n+k,1), etc.

[0228] For different sidelink physical channels, different resource pools may be used. For example, PSCCH may use a first resource pool, and PSSCH may use a second resource pool. Different resource priorities may be associated with different resource pools. For example, data associated with a first QoS, service, priority, and / or other characteristics may use the first resource pool, and data associated with a second QoS, service, priority, and / or other characteristics may use the second resource pool. For example, a network (e.g., a base station) may configure the priority level of each resource pool, the services supported for each resource pool, etc. For example, a network (e.g., a base station) may configure a first resource pool for use by unicast UEs, a second resource pool for use by groupcast UEs, etc. For example, a network (e.g., a base station) may configure a first resource pool for transmitting sidelink data, a second resource pool for transmitting discovery messages, etc.

[0229] In sidelink operation, system performance may be limited by in-band emissions. In-band emission (IBE) is the interference imposed on another transmitter transmitting to a receiver on another subchannel, caused by one transmitter transmitting on one subchannel. FIG. 19 is a diagram showing a plot of an in-band emission model for a transmitted signal. The plot of the in-band emission model shows that nearby subchannels and other subchannels (such as I / Q or image subchannels) receive more interference from the transmitted signal.

[0230] When the D2D UE operates in the cellular network, the power radiated by the D2D UE may cause severe interference to cellular communication. In particular, when the D2D UE uses only some frequency resources in a specific slot or subframe, the in-band emission of the power radiated by the D2D UE may cause severe interference to other frequency resources in the specific slot or subframe used in cellular communication. To prevent this problem, the D2D UE may perform cellular path loss-based power control to control the transmission power of the D2D UE. The parameters used for power control can be configured by the base station. The transmission power P of the D2D UE can be calculated using one or more of the following parameters: P0 (minimum transmission power), alpha (path loss compensation value), and path loss estimation by the transmitter UE or the receiver UE from the base station. The transmission power P can be calculated as P = P0 + alpha * path loss.

[0231] In D2D communication, the transmitting UE may accommodate a half-duplex UE that cannot perform reception while the UE is transmitting. The transmitting UE may not be able to receive the transmission of another UE due to the half-duplex problem. To mitigate this half-duplex problem, different D2D UEs performing communication can transmit signals in one or more different time resources.

[0232] D2D operation may have various advantages in that D2D communication is generally performed between devices that are relatively close to each other (e.g., compared to the communication between a UE and a base station). D2D operation can also have a high transfer rate and low latency and can perform data communication. Furthermore, in D2D operation, traffic concentrated on the base station can be distributed. When the D2D UE serves as a relay, D2D operation can also extend the coverage of the base station.

[0233] The above D2D communication can be applied to signal transmission and / or reception between vehicles. Vehicle-related communication may be referred to as vehicle-to-everything (V2X) communication. In V2X, X may refer to a pedestrian, in which case V2X may be represented by V2P (communication between a vehicle and a device carried by an individual (e.g., a handheld terminal carried by a pedestrian, cyclist, driver, or passenger)), may refer to a vehicle, in which case V2X may represent V2V (communication between vehicles), and may refer to infrastructure / network, in which case V2X is represented by V2I / N (communication between a vehicle and a roadside unit (RSU) / network). The RSU can be a transport infrastructure entity (e.g., an entity that transmits speed notifications) implemented in a base station or a stationary UE. For V2X communication, vehicles, RSUs, and handheld devices may include transceivers. FIG. 20 shows diagrams of various V2X communications including V2V, V2P, and V2I / N.

[0234] Warnings for various events can be indicated using V2X communication. For example, information about an event occurring on a vehicle or on the road can be notified to another vehicle or pedestrian via V2X communication. For example, information about a traffic accident or a change in road conditions can be transferred from one vehicle to another vehicle or pedestrian. For example, a pedestrian adjacent to or crossing a road can be informed of information by a vehicle traveling on the road and approaching the pedestrian.

[0235] In V2X communication, one challenge is to avoid collisions between V2X transmissions on the wireless channel and ensure a minimum level of communication quality even in high-density UE scenarios. Radio congestion control can represent a series of mechanisms to mitigate such collisions by adjusting one or more communication parameters to control the congestion level on the wireless channel. The wireless device measures the following two metrics to characterize the state of the wireless channel, which may enable the wireless device to take measures necessary to control congestion on the wireless channel. The first metric can be the Channel Busy Radio (CBR), which can be defined as the portion (or number) of subchannels within a resource pool where the measured RSSI exceeds a (pre-)configured threshold. The frequency resources of the resource pool can be divided into a number of subchannels. Such a metric can be sensed, for example, over 100 slots or subframes. CBR can provide an estimate of the state of the wireless channel. The second metric can be the Channel Occupancy Rate (CR). CR may be calculated in slot or subframe n and may be defined as the number of subchannels used for sidelink transmissions in slots n-a to n-b, where a and / or b may be determined by the wireless device or may be fixed parameters. CR can provide an indication regarding the channel utilization by the wireless device itself. For each CBR value detected at a certain interval (e.g., 100 slots or subframes), the CR limit can be defined as a footprint that the transmitter must not exceed. Different CR limits can be configured by the base station for different ranges of CBR values and packet priorities. For example, a lower CR limit can be configured for a higher range of CBR values than for a lower range of CBR values. In another embodiment, a lower CR limit can be configured for a lower packet priority than for a higher packet priority.

[0236] When a wireless device decides to send a packet, the wireless device may map the sensed CBR value to a CBR range to obtain a corresponding CR limit value. If the calculated CR of the wireless device is higher than the CR limit, the wireless device can reduce its CR to be lower than the CR limit. In one embodiment, one or more of the following techniques can be used to reduce the CR limit of the wireless device. 1) Drop packet retransmission: If the packet retransmission function (e.g., the function to retransmit a packet that the receiver did not receive properly) is enabled, the wireless device may disable the retransmission function. 2) Drop packet transmission: The wireless device may drop a packet for transmission (including retransmission of the packet if such a retransmission function is enabled). 3) Adapt the MCS: The wireless device can reduce its CR by enhancing the MCS index used by the wireless device to send data or information. 4) Adapt the transmission power: The wireless device may reduce the transmission power, as a result, the overall CBR in the area can be reduced, and the value of the CR limit can increase. The third technique can reduce the number of subchannels used for transmission. However, increasing the MCS reduces the robustness of the message, and thus narrows the message range.

[0237] To support various V2X services such as autonomous driving, platooning, remote driving, and see-through, some services can be supported by unicast or groupcast instead of broadcast to improve resource efficiency. Groupcast means that communication can occur only among group member UEs, and unicast means that communication can occur between a single transmitter and a target receiver UE. Broadcast means that communication can occur among all UEs within the communication range. For example, platooning, which can reduce fuel consumption by forming a group of vehicles, may require exchanging messages among vehicles within a specific platooning group. In another example, a single target receiver can be considered in a see-through service where a vehicle can deliver a forward image or video to a vehicle behind it. In such scenarios, unicast can be used to transmit the forward image or video from the forward vehicle to the rear vehicle. Since these various V2X services must operate reliably in the absence of network coverage, they need to operate in "sidelink" communication using unicast, groupcast, or broadcast.

[0238] In one embodiment, a wireless device may perform a sensing operation for resource selection in sidelink communication. In the sensing operation, the wireless device may decode one or more physical sidelink control channels (PSCCHs) of other wireless devices during a first period. The first period may be referred to as a "sensing window". Based on the decoding of one or more PSCCHs within the sensing window, the wireless device may identify one or more resources that can be used or reserved for sidelink transmission within a second time period. The second time period may be referred to as a "selection window". The wireless device may select one or more transmission resources in the selection window that cannot be used by other wireless devices.

[0239] In some embodiments, "constituting something" may mean transmitting a configuration message indicating something. The configuration message may be one or more configuration messages. The configuration message may be transmitted / signaled / received via the SIB. The configuration message may be transmitted / signaled / received via the RRC. The configuration message may be transmitted / signaled / received via the DCI. The configuration message may be transmitted / signaled / received via the sidelink RRC. The configuration message may be transmitted / signaled / received via the sidelink MAC CE. The configuration message may be transmitted / signaled / received via the sidelink control information.

[0240] In the existing technology, when there is an emergency packet to be transmitted to a wireless device, a preemption operation may be implemented. The existing sidelink preemption operation may use a preemption SCI format or a preemption field in the SCI to indicate preemption of one or more sidelink radio resources from other wireless devices. In one example, the preemption operation may use the priority of a transport block (e.g., indicated by the SCI) as an indication of preemption of other UEs. For example, a wireless device may transmit a preemption signal (e.g., using the SCI) to use resources already reserved by a second wireless device. In response to receiving the preemption signal, the second wireless device may perform resource reselection without using the resources. For example, a wireless device may transmit an SCI including a sidelink transport block and the priority of the transport block. The priority may indicate that other UEs using the resources of the transport block will be preempted. Implementing the existing technology may result in too many wireless devices preempting resources reserved by other wireless devices. When too many resource reselections are triggered, packet drops occur frequently. These may reduce the performance of the entire system. When the congestion level of the sidelink is high, resource collisions occur in the sidelink, and the performance may degrade.

[0241] Exemplary embodiments of the present disclosure perform enhanced sidelink preemption operations. The base station may transmit to the first wireless device one or more RRC configuration parameters including a priority threshold for preemption of sidelink transmissions. The priority threshold may be used by the preempting wireless device for transmission of preemptive traffic. The priority threshold may be used by the preempted wireless device to determine when one or more radio resources are to be preempted. By setting the priority threshold, the base station can control the preempting resources secured by other wireless devices. Thereby, the amount of preempting resources and resource reselection can be limited. Exemplary embodiments perform a drop behavior when a preemption indication is received. For example, a wireless device may receive a preemption indication. The wireless device can select one or more resources for transmission. The preemption indication may indicate one or more preempting resources. The wireless device may drop one or more preempting resources and resources that partially or completely overlap with the selected resources, rather than all of the selected resources. Thereby, excessive packet drops can be prevented and the amount of resource reselection can be limited. Based on the exemplary embodiments, high-priority packets may achieve better performance and increase sidelink transmission efficiency. From the perspective of the preempted wireless device, by controlling the amount of preemption operations in the network, the exemplary embodiments may reduce resource reselection and packet delay due to excessive packet drops.

[0242] In an exemplary embodiment, the base station may transmit one or more configuration messages indicating a priority threshold for preemption to a first wireless device. The first wireless device may receive sidelink control information (SCI) indicating priority and resource allocation from a second wireless device. The resource allocation may indicate one or more first resources. The first wireless device may reserve or select one or more second resources. If the priority indicates a priority higher than the threshold and there is (fully or partially) an overlap between the one or more first resources and the one or more second resources, the first wireless device may drop a portion of the one or more second resources.

[0243] The first wireless device may determine that there is a resource overlap between one or more first resources of a sidelink transport block and one or more second resources of one or more sidelink transmissions of the first wireless device. The first wireless device may determine that the overlapping resources are to be preempted based on the priority and the priority threshold. Thereby, the wireless device can selectively determine preemption based on the priority of the transport block and the configured priority threshold. For example, this can limit preemption to a limited type of traffic and reduce dropped sidelink packets.

[0244] The first wireless device may determine one or more third resources for dropping. The one or more third resources may be determined based on the priority, the priority threshold, and the one or more first resources. The first wireless device may drop a first portion of the one or more second resources. The one or more second resources may overlap with the one or more first resources. The first wireless device may drop the transmission via the overlapping resources. Thereby, preemption to the overlapping resources is reduced and sidelink transmission efficiency is improved.

[0245] In one embodiment, configuring a priority threshold used as a condition for resource reselection by preemption may be beneficial for leading too many resource reselections. For example, the base station may configure the threshold to be 2. That is, only the priority level 1 can be a preempting wireless device or a preempting resource. It can be assumed that the lower the priority level, the higher the priority. Therefore, the priority level 1 may be the highest priority. In one embodiment, the first wireless device may receive an SCI indicating a priority and one or more first resources. When the priority is equal to or higher than the priority threshold, since the priority of the packet of the second wireless device does not meet the preemption condition, the first wireless device cannot drop the secured or selected resource (for example, one or more second resources).

[0246] When the first wireless device determines that there is an overlap between one or more first resources and one or more second resources, the first wireless device may determine one or more third resources for dropping. For example, the one or more third resources may include one or more second resources that completely or partially overlap with the one or more first resources. This method can prevent excessive dropping. Since only the (completely or partially) overlapping resources can be dropped, the amount of resource reselection cannot become large. Resource reselection is only required for a part of the secured / selected resources. Based on the exemplary embodiment, a wireless device having a high-priority packet may achieve better performance and may also avoid overly frequent resource reselections.

[0247] In one embodiment, a sidelink control signal (e.g., PSCCH) is frequency division multiplexed (FDM) with a related data channel (e.g., PSSCH) as shown in FIG. 21. This FDM control / data channel multiplexing can have a larger sensing coverage because more energy can be allocated to the control channel, but the decoding delay can increase because data channel decoding cannot be started from the perspective of the receiving UE until control channel decoding is completed. In one embodiment, the control channel is limited to two symbols within a slot (e.g., a short duration compared to the duration of the related data channel) to reduce the decoding delay.

[0248] Figure 22 shows an example of control / data channel multiplexing that can reduce decoding latency. In one embodiment, the wireless device transmits a control channel only without an associated data channel within a slot to reserve resources for an initial packet transmission or to indicate preemption for one or more resources. For example, the wireless device may indicate preemption to a second wireless device via a control channel. In response to receiving the preemption indication, the second wireless device may generate resources based on the indication and may drop one or more reserved resources. The second wireless device may trigger resource reselection for one or more transmissions of packets having high priority, low target latency, or high target reliability (e.g., successful decoding rate or one-block error rate (BLER)). When the UE transmits a preemption signal (e.g., a control channel including a preemption indication). The preemption signal may include one or more first resources, priorities, and preemption indications. In response to receiving the preemption signal, a wireless device that is a transmitter wireless device and for which one or more second resources have been reserved / assigned / selected. The wireless device may determine one or more third resources to be produced or released or dropped. The one or more third resources may be determined based on the one or more second resources and the one or more first resources. The one or more third resources may partially or completely overlap the resources of the one or more second resources between the one or more first resources and the one or more second resources. The wireless device may determine the one or more third resources based on the priorities and / or the one or more first resources indicated by the preemption signal. The wireless device may release or drop sidelink transmissions on the one or more third resources to enhance the delivery ratio of packets having high priority, low target latency, large target coverage, or high target reliability. For example, the one or more third resources may be the same as the one or more second resources.For example, one or more third resources may be common resources between one or more first resources and one or more second resources.

[0249] In one embodiment, the first wireless device may transmit a first control channel (e.g., a preemption signal) without an associated data channel via K OFDM symbols (e.g., K < 14) of the OFDM symbols in a slot. The second wireless device may transmit a second control channel having an associated data channel via M OFDM symbols (e.g., M = 14). The third wireless device may receive the first control channel and the second control channel together with an associated data channel. Different transmission durations of a plurality of sidelink transmissions may result in more frequent automatic gain control (AGC) readjustment operations at the third wireless device (e.g., Rx UE). Without more frequent ACG readjustment (e.g., at the first OFDM symbol, after the first control channel transmission, etc.), the AGC adjustment value measured at the first symbol of the slot may be inaccurate, resulting in a degradation of the overall reception performance. FIG. 23 shows an embodiment. In one embodiment, a preemption indication signal (e.g., a preemption PSSCH) is transmitted via some of the first symbols of a slot. With the power change after the preemption indication, the receiving wireless device may require additional AGC adjustment (or AGC readjustment) on the symbol immediately after the preemption indication signal is transmitted. For example, if the wireless device can utilize the next OFDM symbol after the transmission of the preemption indication signal for additional ACG readjustment, the receiving wireless device may not be able to reliably receive data transmissions scheduled by a normal PSCCH (e.g., Normal PSSCH) during the AGC adjustment period. Alternatively, due to the AGC readjustment operation, some of the encoded bits of the data may be destroyed by the receiving UE, and thus the decoding performance may be significantly degraded.

[0250] Exemplary embodiments of the present disclosure define a signal repetition method for achieving greater coverage and achieving less impact on the transmission and reception of other signals. For preemption signals, some signal repetition methods within a slot are presented to avoid the problem of readjustment of the AGC. When a UE transmits a preemption signal, a dedicated DMRS sequence for the preemption signal can be allocated. The receiving UE may recognize the presence and repetition of the preemption signal within the slot so that the receiving UE performs combining the repetitions of the preemption signal. Accordingly, the decoding performance and the coverage of the preemption signal can be enhanced.

[0251] In an exemplary embodiment, a specific DMRS may be dedicated to transmitting sidelink preemption signals, and different DMRSs may include different sequence initialization identities (e.g., scrambling IDs), different DMRS RE mapping patterns / methods (time and / or frequency positions), or different cyclic shifts (CSs) applied to the sequence. For example, a sequence initialization ID may be assigned to the DMRS of the preemption signal. The physical channel for transmitting the preemption signal may have the same or a similar signal format as the PSCCH for PSSCH resource scheduling and / or reservation in terms of channel coding, scrambling, modulation, mapping from codewords to REs, transmission scheme, DMRS resource element (RE) mapping, etc. When generating the DMRS of the PSCCH, a specific sequence initialization ID can be assigned to the DMRS sequence of the preemption signal. The base station may transmit a control message including a specific DMRS sequence initialization ID for the preemption signal to the UE via the physical layer (e.g., DCI) or a higher layer signal (e.g., SIB or RRC or MAC CE). The purpose of assigning different DMRS sequences to sidelink control signals for preemption may be to reduce the complexity of blind decoding or enhance the decoding performance. This can also increase the probability of successful channel decoding even when there is an overlap with other control channels by assigning a dedicated DMRS sequence to the preemption signal. For an external network coverage UE, the DMRS sequence initialization ID for the preemption signal may be preconfigured. FIG. 25 shows an example where the base station configures the DMRS sequence initialization ID of the preemption signal for a sidelink UE, and the first UE transmits the preemption signal with a DMRS sequence having the configured sequence initialization ID. The second UE reserves one or more resources that may overlap (in whole or in part) with what the first UE wants to preempt. Upon receiving the preemption signal, the second UE may drop packet transmissions from the overlapping resources (completely or partially).The third UE in the figure represents the UE that receives the preemption signal or another PSCCH / PSSCH as the Rx UE.

[0252] In one embodiment, the wireless device may use a first DMRS RE mapping for the PSSCH for a first SCI that includes a resource allocation for one or more PSSCHs associated with the corresponding PSSCH. The wireless device may use a second DMRS RE mapping for the PSSCH for a second SCI that includes a preemption indication for one or more resources not associated with the corresponding PSSCH. FIG. 26 shows an example where the preemption signal (e.g., the second SCI) may have a DMRS RE mapping different from that of a normal PSCCH, where the normal PSCCH means a PSCCH used for scheduling or securing one or more PSSCHs and is transmitted on the associated PSSCH within a slot. This method uses the same sequence generation method but different RE mappings so that the Rx UE can detect the presence of the preemption signal in the DMRS detection step. The size of the (periodic) frequency shift of the DMRS RE of the preemption signal in the frequency domain may be pre-set / pre-configured or the base station may indicate it to the UE via the physical layer (e.g., DCI) or a higher layer signal (e.g., SIB or RRC). In one embodiment, the wireless device may divide a plurality of priority levels or groups of a plurality of priority levels by the number of DMRS sequences (e.g., K, K = 4), and / or the DMSR RE pattern of the PSCCH may be set differently for each group. In an embodiment, the DMRS sequences may be distinguished based on a sequence initialization identity (e.g., a scrambling ID), and / or a DMRS RE mapping pattern / method (time and / or frequency position), and / or different periodic shifts applied to the sequences, and / or a periodic shift mapping in the time and / or frequency domain. In one embodiment, different periodic shifts of the DMRS for the preemption signal may be applied. In the case of a sidelink PSCCH, the UE may assume that the demodulation reference signal (DMRS) sequence r l (m) for OFDM symbol l is defined by:

Number

[0253] where c(i) is a pseudo-random sequence. The pseudo-random sequence generator can be [Number] initialized with

[0254] where l is the OFDM symbol number within a slot, [Number] may be the sidelink slot number or the slot number within a frame, and [Number] may be given by the upper layer for the PSCCH or the preemption signal. In one embodiment, [Number] has a subcarrier spacing of 15 kHz * 2 μWhen it is, it can be the slot number counted only during the period of the frame or resource pool configuration, or the resource pool bitmap length, or the sidelink slot within the system frame number period (= 10240 ms). For example, if the resource pool can define slots for each P slot, the slot index of the first slot is 0, the slot index of the P-th slot is 1, and the slot index of 2P is 2. The modular operation can be applied to the re-indexed sidelink slot index. For example, the sidelink slot number is derived from the re-indexed number only among the sidelink slots within the frame. Figure 27 shows an example of the re-indexing of the sidelink slot number. In this figure, the operation of the module 20 is applied to the re-indexed slot number. The value of the modular operation (after the modular value should be smaller than this value) can be determined based on the number of slots present in one frame according to the subcarrier spacing. For example, for SCSs of 15 kHz, 30 kHz, 60 kHz, 120 kHz, 240 kHz, the operations of modules 10, 20, 40, 80, 160 can be applied to the re-indexing of the slot number respectively. This is because when the sidelink resource pool is assigned to the same slot position for each frame, the sequence may not be sufficiently randomized. Therefore, when the sidelink slots are collected again and then re-indexed, the re-indexed slot index can be used for sequence generation. The first resource and the second resource sharing the same slot index in different radio frames may use different sequence generations in the approach, which can promote the overall randomization of the DMRS sequence for the periodic sidelink resource pool configuration. This is because it can be sufficiently randomized regardless of the configuration of the resource pool. N ID can be configured differently between the normal PSCCH and the preemption signal. When a periodic shift is applied to the DMRS, r l (α) (m)=e jam rl(m) can be used for the DMRS sequence of the PSCCH or the preemption signal. For example, the second periodic shift value α may be assigned to the preemption signal, and the first periodic shift value may be assigned to the normal PSCCH. The second periodic shift value may be different from the first periodic shift. For example, π / 2 may be used as the periodic shift value of the DMRS for the preemption signal, and {-π / 2, 0, π} may be used as the periodic shift value of the DMRS for the normal PSCCH. The periodic shift value can be determined to achieve high sequence separation (e.g., orthogonality). The exact periodic shift value of the preemption signal may be pre-determined by the base station via the physical layer (e.g., DCI) or the upper layer signal (e.g., MAC CE or SIB or RRC), or can be signaled to the UE. In one embodiment, the wireless device may divide a plurality of priority levels or a plurality of priority levels into a plurality of groups, and the periodic shift value of the DMRS sequence of the PSCCH can be set differently for each group. For example, different sets of periodic shift values can be assigned to each priority group. For example, DMRS CS set A is used for priority levels 1 to K (e.g., K = 4), and DMRS CS set B is used for priority levels K + 1 (e.g., K = 5) to N (e.g., N = 8). In this embodiment, the UE can randomly select the DMRCS in the set of DMRS CS. This is to select the PSCCH DMRS periodic shift value differently in the same set so that the control channel can be decoded even if a resource collision occurs.

[0255] In one embodiment, the wireless device may use one or more second scrambling sequences for the preemption signal to distinguish the codeword of the preemption signal from another PSCCH (e.g., a normal PSSCH) having one or more first scrambling sequences. The one or more second scrambling sequences may provide an additional randomization effect when there are multiple PSSCHs. To do this, the initialization of the scrambling sequence may be generated differently. For example, the initialization of the scrambling sequence of the existing PDCCH is generated by the following equation.

Number

Number

Number

[0256] For the PSCCH, the base station may configure N ID for the PSCCH via the SIB and / or RRC. N ID may be the same as the DMRS sequence generation ID. Different N ID for the scrambling of the preemption signal and / or the generation of the DMRS sequence may be configured by the base station via the SIB or RRC. On the other hand, n RNTImay be set to 0 or a predetermined value for the PSCCH, regardless of the RRC state of the UE or whether the RNTI has been received. Alternatively, a separate n for the PSCCH and / or the preemption signal RNTI can be signaled from the base station to the UE by a physical layer (e.g., DCI) or a higher layer signal (e.g., SIB or RRC or MAC CE).

[0257] In one embodiment, the base station may indicate all or part of the DMR RE position (time / frequency resource of the DMRS) and / or the CDM code and / or the number of antenna ports of the DMRS to the sidelink UE to transmit a preemption signal via a physical layer (e.g., DCI) or a higher layer signal (e.g., MAC, SIB, or RRC). This may be to make the DMRS of the preemption signal orthogonal to the DMRS of other control signals by allocating specific REs and CDM codes of the DMRS of the preemption signal. Further, the DMRS power boost value for the preemption signal may be signaled to the UE as a physical layer (e.g., DCI) or a higher layer signal (e.g., MAC, SIB, or RRC). In the case of the preemption signal, a separate DMRS power boost for the preemption signal may be required to achieve wide coverage so that it can be configured to improve channel estimation performance and expand coverage compared to other control signal transmissions.

[0258] In an exemplary embodiment, the preamble signal may include a series of OFDM symbols, and the preamble signal may be continuously repeated within the sidelink slot and may span the entire sidelink slot. For example, the preamble signal may be repeated within one or more sidelink slots so as to cover the same duration as the PSSCH transmission. This operation is to avoid additional AGC adjustment within the slot and / or within the PSSCH transmission. The time-domain repetition may span the entire sidelink slot or several slots over which the preamble signal is transmitted. For example, if the sidelink slot format information (e.g., slot format information indicating one or more OFDM symbols within the slot where sidelink communication is allowed) changes over time, or if the number of OFDM symbols constituting one sidelink slot (e.g., the portion where sidelink operation is allowed within the slot) is variable, when the last repetition of the preamble signal does not completely construct one preamble signal, only a part of the symbol may be transmitted in the last repetition. When the PSFCH resource is set to several last symbols from the end of the slot, the repetition of the preamble signal may be limited to only the OFDM symbols in the PSSCH region (e.g., excluding one or more OFDM symbols for the PSFCH resource). FIG. 28 shows an example of the repetition of the preamble signal. The preamble PSCCH may have the same SCI format as the normal scheduling / reservation PSCCH, but different DMRS sequences, and / or different DMSS RE mappings, and / or different antenna ports may be used as presented in other embodiments. For example, the sidelink slot may have 14 OFDM sidelink-capable symbols. Assuming that the number K of OFDM symbols for the PSSCH transmission is divisible by 14, the wireless device may repeat 14 / K times within the sidelink slot.If K cannot be divided by the number of OFDM symbols of the M-side linkable symbols (e.g., K = 3 in the 14 OFDM symbol side link slots), the wireless device may repeat the floor (M / K) times for the preemption signaling. One or more remaining symbols may be transmitted to other OFDM symbols with meaningless / valueless data at the same power. In one embodiment, the repetition pattern (e.g., the number of PSSCH symbols in each repetition of a slot or several slots) may be configured to perform the repetition of the preemption indication signal.

[0259] Figure 29 shows an example of partial repetition of preemption. For example, assuming that the side link slot is composed of 13 OFDM symbols (i.e., excluding the last symbol of Tx / Rx switching in a normal slot) and the preemption signal is composed of 3 OFDM symbols, only the first symbol of the preemption signal is transmitted for the last retransmission of the preemption signal. Figure 30 shows an example of the repetition of the preemption signal for only the PSSCH region. If some of the last symbols are set for PSFCH transmission, that part is not used for preemption signal transmission.

[0260] In one embodiment, a UE receiving a preemption signal first blindly detects DMRS, and if a DMRS of a preemption signal having a predetermined threshold (e.g., RSRP threshold) or high power is detected, the UE may assume that the preemption signal is repeatedly transmitted until the end of the slot or to the PSSCH region within the slot. The receiving UE may perform a code combining (e.g., HARQ combining) operation while receiving the repetition. The preemption signal transmitting UE may use a predetermined RV pattern in the repetition of the preemption signal. For example, the RV pattern [0,0,0,0,...] or [0,3,0,3,...] or [0,2,3,1,0,2,...] may be used. The RV pattern used in the preemption signal repetition within and / or between slots may be pre-set by the base station as a physical layer (e.g., DCI) or a higher layer signal (e.g., MAC, RRC, SIB), or may be signaled to the UE.

[0261] In one embodiment, the entire sidelink slot within a slot or the PSCCH format across the PSSCH region may be used for preemption signal transmission. This may require a little more complexity in blind decoding from the perspective of the receiving UE. To reduce the complexity of blind decoding, the OFDM symbol number of the DMRS symbol of the PSSCH format may be the same as that of a normal PSCCH, but a different DMRS sequence may be used for the PSCCH format. FIG. 31 shows an example of an additional PSCCH format for preemption signal transmission. This method may avoid the problem of additional AGC readjustment within the slot.

[0262] In one embodiment, a dummy signal having a preamble PSCCH may be transmitted in the same slot and / or the same subchannel. In this case, the dummy signal may be transmitted by encoding the SCI information of the preamble PSCCH into the PSSCH, or any information determined by the UE may be transmitted. FIG. 32 shows an example of dummy signal transmission of the preamble signal. In this case, the dummy signal may be transmitted only by being limited to the frequency domain in which the preamble PSCCH is transmitted, or may be transmitted by filling the PSSCH region of the subchannel in which the PSCCH is transmitted.

[0263] In one embodiment, the preamble signal for the PSCCH or the preamble may be repeated a predetermined number of times within the sidelink slot, and the dummy signal may be transmitted in the remaining region within the sidelink slot. If it is difficult for the repetition of the PSCCH to completely fill the slot, or if partial repetition is required, this method fills the slot with the dummy signal. The dummy signal may simply be additionally transmitted to avoid problems with readjustment of the AGC.

[0264] In one embodiment, for scheduling a PSSCH whose priority level exceeds (or is below) a specific threshold, a preemption signal or a preemption PSCCH or a PSCCH for ensuring an initial PSSCH transmission may be transmitted in a separate resource pool. Note that in some cases, the smaller the number of priority levels or indicators, the higher the priority, while in other cases, the larger the number of priority levels or indicators, the higher the priority. If a lower priority level or indicator means a higher priority, a PSSCH whose priority level is below the threshold may be allowed to be transmitted within a separate resource pool. For example, the base station may configure a separate resource pool for the preemption signal or the preemption PSCCH or the PSCCH, and ensure an initial PSSCH transmission or a PSCCH for scheduling a PSSCH having a priority level exceeding (or below) a specific threshold for the UE as a physical layer (e.g., DCI) or a higher layer signal (e.g., MAC CE, RRC, or SIB). For a UE having a packet with a priority level exceeding a specific threshold, this resource pool may be used for the preemption signal for the initial PSSCH transmission or the PSCCH for reservation. One or more conditions for using such a separate resource pool, e.g., a threshold of the priority level or a target delay level, or a threshold of the target reliability or a threshold of the target coverage, may be signaled to the UE by the base station via a physical layer (e.g., DCI) or a higher layer signal (e.g., MAC CE, RRC, or SIB). FIG. 34 shows an example of a preemption PSCCH resource pool. This pool can be used for stand-alone PSCCH transmission. This may enable better resource availability when transmitting one or more PSSCHs to schedule / reserve resources for high-priority PSSCHs.

[0265] In one embodiment, the wireless device may perform RSRP measurements based on one or more PSSCHs. If a first wireless device can transmit a PSCCH without an associated PSSCH, a second wireless device may be unable to perform measurements on the PSCCH, which may be inefficient in the resource sensing / selection procedure. In this case, a method of substantially deriving the PSSCH-RSRP by measuring the PSCCH-RSRP may be considered. For example, if a stand-alone PSCCH is transmitted in N RBs and / or this PSCCH performs scheduling or preemption indication of M RBs, then the PSCCH RSRP of the N RBs is first measured, and the PSSCH RSRP is substantially derived based on applying an M / N scaling factor to the PSCCH RSRP. The second wireless device may derive the RSRP based on measurements on the PSSCH from the first wireless device. Note that the RSRP of the PSCCH or PSSCH may refer to the RSRP of the DMRS or CSI-RS transmitted on the corresponding channel. This method can measure the PSSCH RSRP even when the PSSCH is not being transmitted.

[0266] In one embodiment, the PSCCH for preemption may be repeated not only within a certain slot but also transmitted in multiple slots. The base station may indicate the number of repetitions within a slot of the preemption signal and / or the number of repetitions between slots to the UE as a physical layer (e.g., DCI) or a higher layer signal (e.g., MAC CE, RRC, or SIB). The UE may transmit the preemption signal by determining the number of repetitions within a slot and the slot of the preemption signal based on the signal. By extending this method, all or part of the transmission power, number of retransmissions, RB (or sub-channel size), and MCS of the preemption signal may be set by the base station (physical layer or higher layer signal to the UE).

[0267] In an exemplary embodiment, for preemption indication, a predetermined sequence may be transmitted within a slot and / or one or more subchannels to indicate preemption. Further, all or part of the sequence type, sequence initialization ID, sequence CS, and RE mapping of the predetermined sequence may be signaled by the base station to the UE as a physical layer (e.g., DCI) or a higher layer signal (e.g., SIB, RRC, or MAC CE). When receiving a preemption signal, the number of slots after which the actual preemption signal (or data or PSSCH) is transmitted may be determined in advance or indicated by the CS or RE mapping of the sequence. For example, if the CS is X, the slot offset (the slot interval between the preemption indication signal and the preemption signal (or data)) may be set to a, and if the CS is Y, the slot offset may be set to b differently. That is, the UE that secures resources with the corresponding offset drops the packet, and the preempting UE transmits the PSSCH with the corresponding offset. FIG. 35 shows an example of a predetermined sequence (or sequence repetition) based on a preemption signal. In this example, the preemption signal may include repetitions of a predetermined sequence. The preempting UE may transmit this signal for preemption indication in slot n, and other UEs may assume that the preempting data signal may be transmitted in slot n + k, where k may be preset or indicated by the CS or RE mapping (or frequency shift) of the preemption signal, or configured by the base station via RRC or SIB.

[0268] In one embodiment, when the preemption signal is transmitted only in one slot, UEs that perform transmission in the same slot may be unable to receive the preemption signal due to the half-duplex problem. FIG. 36 is an example for explaining the problem. Since UE A is transmitting in the same slot n in which the preemption signal is transmitted, it may be unable to receive the preemption indication signal. FIG. 36 shows that since UE A cannot listen for the preemption indication in slot n, UE A cannot execute the preemption procedure. As a result, the performance of PSSCH transmission, which attempts to preempt resources first, deteriorates. As shown in FIG. 37, the preemption signal may be continuously transmitted in multiple slots in order to address such a half-duplex problem. The reason for continuous transmission is that it is necessary to urgently transmit a signal such as the preemption signal to another UE. In this embodiment, when the preemption signal is transmitted, the number of slots for continuous transmission may be preset or signaled to the UE by the base station as a physical layer (e.g., DCI) or a higher layer signal (e.g., SIB, RRC). By repeating the preemption signal transmission, the wireless device may be able to listen for the preemption signal (e.g., UE A) and may release the indicated resources.

[0269] In one embodiment, the preemption indication signal may be transmitted in a separate dedicated resource pool or resource. In this operation, the base station may signal the UE as a physical layer (e.g., DCI) or a higher layer (e.g., MAC CE or RRC or SIB) with the resource region and the resource pool of the preemption indication signal. In this method, since the preemption signal uses a separate resource pool or resource, the reception performance of the preemption signal may be improved.

[0270] Figure 38 shows an example of complete overlap between pre-empting resources and pre-empted resources within a slot. The base station may indicate priority thresholds for the first and second wireless devices. The first wireless device (UE A in the figure) is assumed to be the pre-empted wireless device, and the second wireless device is assumed to be the pre-empting wireless device. The second wireless device may have packets indicating that the priority level is higher than the priority threshold. If a lower priority level or indicator means a higher priority, the priority level of the packets of the second wireless device is smaller than the priority threshold. The second wireless device can send a PSCCH containing sidelink control information to the first wireless device. The sidelink control information may indicate one or more first resources and the priority of the packets. The first wireless device can receive the PSCCH and identify one or more first resources and the priority of the packets. The first wireless device may determine that there is an overlap between one or more first resources and one or more second resources. One or more second resources may be reserved or selected for the sidelink transmission of the first wireless device. In this figure, the first wireless device may reserve / select two sub-channels in different slots. The second sub-channel may completely overlap with any of the one or more first resources. The first wireless device may drop the second transmission. The first wireless device may send a sidelink signal via resources that do not overlap between one or more first resources and one or more second resources. In the figure, the first wireless device may send a first sub-channel that does not overlap with one or more first resources.

[0271] FIG. 39 shows an example of partial overlap between pre-empting resources and pre-empted resources in a slot. The second wireless device may indicate one or more first resources. The first wireless device may determine that there is an overlap between one or more first resources and one or more second resources. In this figure, the first wireless device may reserve / select two sub-channels in slot n+1 and two sub-channels in slot n+k. In slot n+k, one sub-channel overlaps with the pre-empting resources (e.g., one or more first resources). In other words, one or more second resources partially overlap with one or more first resources. Since there is a partial overlap with the pre-empting resources, the first wireless device may drop the sidelink transmission in slot n+k. This prevents interference with the pre-empting resources and allows the pre-empting wireless device to achieve better performance.

[0272] In an exemplary embodiment, the base station may indicate one or more conditions for transmitting a preemption signal to a sidelink UE as a physical layer (e.g., DCI) or a higher layer signal (MAC CE, RRC, or SIB). All or some of these conditions may be pre-set or pre-configured. For example, a UE having a packet priority level above a threshold may be able to transmit a preemption signal. For example, when the congestion level (e.g., CBR measurement) exceeds a threshold, preemption signal transmission may be permitted. In another example, a UE having a target delay requirement for a packet below a threshold may be able to transmit a preemption signal. For example, a UE having a target reliability (e.g., successful decoding rate or one-block error rate (BLER)) requirement for a packet above a threshold may be able to transmit a preemption signal. In another example, a UE having a target coverage requirement for a packet above a threshold (e.g., 1000 meters) may be able to transmit a preemption signal. As another method, a resource exclusion procedure may be performed among a set of candidate resources based on the sensing result, and preemption signal transmission may be permitted when the remaining resource amount is below a threshold.

[0273] Multiple conditions may be configured in combination. Other conditions are not excluded. Any combination of the foregoing conditions may be considered. For example, a UE whose priority level exceeds a first threshold and whose CBR measurement value exceeds a second threshold may be able to transmit a preemption signal for which the first and second thresholds may be (pre-)configured. The base station may indicate any threshold or state for the sidelink UE via RRC or SIB, or the threshold or state may be pre-set. Since preemption signal transmission may cause resource reselection or packet drop of another UE, it is not desirable to permit transmission of a preemption signal to an excessive UE. Therefore, it is desirable to enable preemption signal transmission only when it is difficult for a specific UE or channel condition to find appropriate resources due to a lot of congestion.

[0274] In Mode 1, the UE may request a specific resource or candidate resources from the base station for preemption based on its sensing result. Subsequently, the gNB may schedule multiple resources for pre-empting data transmission. The UE in Mode 1 may select any one to notify the network of the preemption request. If the scheduling in Mode 1 is not satisfactory, for example, with respect to the target delay requirement, the UE in Mode 1 can switch to Mode 2. In an embodiment, the UE may request a new resource for preemption TB transmission. For "sidelink", any new state in the constellation of scheduling requests can be defined. The base station may configure one or more dedicated SR / BSR resources for preemption request resources via signaling of the physical layer (e.g., DCI) or the upper layer (e.g., RRC or SIB). In one embodiment, the UE in Mode 1 may indicate the urgency of scheduling via a sidelink scheduling request. For example, the base station may configure one or more sidelink SR resources that can be used to indicate an emergency scheduling request. In response to receiving a sidelink SR from a resource, the base station may respond with a UL grant within the configured / pre-defined delay. The wireless device may transmit Mode 2 transmission simultaneously with the sidelink SR transmission to ensure the delay requirement.

[0275] / / Repetition of NR sidelink synchronization signal

[0276] In an embodiment of the existing technology, sidelink synchronization signal transmission may be performed with a fixed periodicity (e.g., 160 milliseconds) without repeating within a period. On the other hand, as the sidelink carrier frequency increases, repeated transmission of each synchronization signal within the sidelink synchronization signal period may be required to compensate for greater path loss at higher carrier frequencies. NR In the Uu interface, multiple synchronization signals and synchronization signal and broadcast channel blocks (SSBs) can be transmitted continuously within a synchronization signal period. When this continuous repetition of sidelink SSBs (SL-SSBs) is transmitted in sidelink communication, packet delay can increase. If the repetition of SL-SSBs is continuously allocated in the time domain, other sidelink signal transmissions that are within different frequency resources but temporally overlap with SL-SSB transmissions may become unacceptable due to the half-duplex constraint of the wireless device. Such limitations can increase the packet delay and service interruption time for one or more sidelink transmissions that occur for the same duration as the repetition of the synchronization signal.

[0277] In the existing art, the NR sidelink may have a different numerology from the LTE sidelink. For example, the NR sidelink can be configured with 60 kHz SCS, while the LTE sidelink can have a fixed 15 kHz SCS. When sidelink synchronization signals and broadcast channel blocks (SL-SSBs) are repeatedly transmitted within a synchronization signal period and the repetition of SL-SSBs is allocated within a time with gaps between the repetitions of SL-SSBs, packet drops in the LTE sidelink can occur due to the time-domain overlap between transport block transmissions in the LTE sidelink and SL-SSB transmissions in the NR sidelink. The NR sidelink with 60 kHz SCS may have a slot size about 1 / 4 that of the LTE sidelink with 15 kHz SCS, and a 1 / 4-size overlap may occur between the LTE sidelink and the NR sidelink, resulting in the entire transmission of the LTE sidelink being dropped.

[0278] Exemplary embodiments of the present disclosure implement several repetition methods for sidelink synchronization signal transmission. The repetition of sidelink synchronization signals within a sidelink synchronization period can be divided into a plurality of clusters, where each cluster includes the number of repetitions of the sidelink synchronization signal, and the clusters can be evenly spaced within the sidelink synchronization transmission period. The exemplary embodiments can coexist better with existing sidelink technologies (e.g., LTE sidelink) while distributing overhead / interrupts over multiple time opportunities caused by the transmission and reception of synchronization signals. Based on the exemplary embodiments, a wireless device may achieve better SL-SSB coverage, and the wireless device can meet packet delay requirements.

[0279] In one example, a base station may configure one or more sidelink synchronization signal offsets for the transmission and reception of sidelink synchronization signals. For example, two sidelink synchronization signal offsets for slot 0 of system frame number 0 may be (pre-)configured for SLSS resource indication. One group of UEs may transmit SLSS with the first offset, and other groups of UEs may transmit SLSS with the second offset. The frequency resource (or center) of SLSS transmission may be fixed by existing technologies, but in NR sidelink, the base station may configure the frequency resource of SLSS transmission to the UE via DCI or RRC or SIB. Based on this configuration, the base station may have the flexibility to configure separate sidelink DC carriers or SLSS transmission frequency resources. On the other hand, the base station may transmit a sidelink BWP configuration message to the UE by SIB or RRC. In SIB or RRC, information regarding subcarrier spacing (SCS) may also be configured by the base station.

[0280] In one embodiment, there may be vehicles or UEs that implement NR sidelink as well as LTE sidelink. For example, service (e.g., forward collision warning) signals may be transmitted using LTE sidelink, and signals for another service (e.g., see-through is transmitted to a small vehicle when a large vehicle in front of the small vehicle blocks the view, image, or video of the camera of the vehicle in front) may be transmitted using NR sidelink. In such UE implementations, time synchronization between LTE and NR sidelink may be preferred, and even when using different subcarrier intervals in NR than in LTE, it may be desirable to transmit signals for the same duration, at least from the perspective of transmitting synchronization signals. When NR uses a different subcarrier interval than LTE, for example, assuming a 60 kHz SCS is used for NR sidelink, one slot of NR sidelink occupies 1 / 4 of an LTE subframe. However, if there is a mismatch between LTE sidelink signals and NR sidelink signals, either one may be dropped according to signal priority even though a part of the subframe or slot simply overlaps. Therefore, at least in transmitting synchronization signals, it may be desirable for LTE and NR to occupy the same duration to prevent such inefficient signal transmission and drop problems. To address these issues, exemplary embodiments present a method for determining the time resource allocation of SLSS transmission resources when SLSS repetitions are configured within an SLSS transmission period.

[0281] In some embodiments, SLSS may have the same meaning as SL-SSB. For example, SLSS transmission may mean that SLSS can be transmitted on the PSBCH within a slot. This may mean that SLSS transmission may mean SL-SSB transmission.

[0282] In some embodiments, a cluster of repetitions of SL-SSB may mean continuous transmission of repetitions of SL-SSB. One or more clusters may be transmitted with a gap between adjacent clusters of the one or more clusters. The gap size may be zero or more. The gap size may be indicated by the base station or may be pre-configured.

[0283] In some embodiments, the size of a cluster of repetitions of SL-SSB may mean the number of repetitions of SL-SSB within the cluster. If the size of the cluster is 2, two repetitions of SL-SSB may be transmitted in consecutive slots as a cluster.

[0284] In an exemplary embodiment, a first wireless device may receive, from a base station, one or more configuration messages indicating a first number of repetitions of sidelink synchronization signal blocks (SL-SSB) within synchronization signal periodicity and a timing gap between adjacent transmissions of clusters of repetitions of SL-SSB. The first wireless device may transmit, to one or more second wireless devices, clusters within the timing gap between each adjacent transmission of the cluster during synchronization signal periodicity, where the cluster includes the first number of repetitions of SL-SSB and each of the clusters includes a second number of consecutive repetitions of SL-SSB.

[0285] In one example, the first number may be pre-configured. In one example, the base station may indicate the first number to the first wireless device via SIB or RRC. The second number may be pre-configured. The base station may indicate the second number to the first wireless device via SIB or RRC. The second number may be determined based on the SL-SSB of the sidelink BWP or the SCS of the SCS. For example, 15 kHz SCS, 30 kHz, 60 kHz, The second numbers of the 120 kHz and 240 kHz SCSs can be 1, 2, 4, 8, and 16 respectively. This can be because a certain cluster of the clusters extends over a duration of 1 millisecond. For example, for the 30 kHz SCS, one slot may extend over 0.5 milliseconds, and two sizes for the cluster may extend over 1 millisecond.

[0286] In an exemplary embodiment, the UE may receive from the base station one or more configuration messages indicating / including one or more sidelink synchronization signal offsets, the number of repetitions of the SLSS or SL-SSB within the sidelink synchronization signal (SLSS) transmission period, and the SCS of the SLS. In one example, the SCS may be configured as part of the sidelink BWP configuration. In one example, the SLSS transmission period may be a fixed number. In one example, the SLSS transmission period is 160 milliseconds.

[0287] In one embodiment, the UE may determine the size of the cluster of SLSS repetitions based on the SCS of the SLS. For example, the sizes of the clusters for 15 kHz SCS, 30 kHz, 60 kHz, 120 kHz, and 240 kHz SCS are 1, 2, 4, 8, and 16 respectively. The size of the cluster may mean the number of SL-SSBs or SLSS slots of SL-SSBs that are repeated continuously in time. The size of each cluster within the SLSS transmission period may be determined by the highest value of the number of repetitions divided by the size of the cluster. Further, each cluster is equally spaced within the SLSS transmission period, and the SLSS repetitions of each cluster are assigned to consecutive sidelink slots within the SLSS transmission period. FIG. 40 shows two examples of 60 kHz SCS. In the first embodiment of FIG. (a), the SLSS repetition pattern is illustrated when 32 repetitions are configured for the SLSS repetitions within a 160 millisecond SLSS transmission period. As proposed, for 60 kHz SCS, the size of the clutter is 4 and the number of clusters is 8. As an example, each cluster transmitted every 20 milliseconds is illustrated, but the interval between clusters may be configurable. For example, the base station may configure the space of the cluster (or the duration or number of slots between clusters) via the SIB or RRC. FIG. (b) shows an example where 16 repetitions are configured for the SLSS repetitions within a 160 millisecond SLSS transmission period. A longer interval between clusters is illustrated. In these figures, it is assumed that the SLSS offset is 0. If a non-zero SLSS offset is configured, the starting offset may be the mode (sell (SLSS offset / SLSS transmission period)).

[0288] In one embodiment, the wireless device can receive one or more configuration messages indicating at least one of a sidelink synchronization signal offset, the number of repetitions of the SL-SSB within the periodicity of the sidelink synchronization signal (e.g., the repetition of the first number of SL-SSBs within the periodicity of the sidelink synchronization signal), the size of the cluster (e.g., the repetition of the second number of SL-SSBs of the cluster), the timing gap between clusters, and / or the number of clusters within the periodicity of the sidelink synchronization signal. The one or more configuration messages can be an SIB or an RRC.

[0289] In one embodiment, the base station can set for the UE a synchronization signal offset, and / or the size of the cluster, and / or the time gap (or time) between clusters, and / or the number of clusters, for the repetition of the synchronization signal in the SLSS period via the SIB or the RRC. This embodiment is more flexible in determining the cluster size than the previous example. FIG. 41 shows an example of the disclosed method. For 60 kHz SCS, the base station can configure a cluster size of 8 and a 20 millisecond period between clusters.

[0290] FIG. 42 shows an example of an embodiment. The base station can indicate a cluster size of 1 and a timing gap between clusters. In this embodiment, the cluster includes the repetition of one SL-SSB. This embodiment can reduce packet drops or packet delays because the repetition of the SL-SSB within the sidelink synchronization signal periodicity is distributed over time.

[0291] On the one hand, when the SLSS offset between the LTE sidelink and the NR sidelink is shifted and set in the UE, packet transmission (e.g., PSSCH and / or PSCCH) can be frequently dropped or interfered with by transmitting and receiving synchronization signals of another radio access technology (RAT). If possible, it is desirable that the LTE synchronization signal offset and the NR synchronization signal offset be set equal. However, this method can vary depending on the combination of bands in which the NR and LTE sidelinks operate, or the UE capabilities or implementation. For example, when LTE and NR operate in the same or adjacent bands, the base station may have a sidelink synchronization signal offset common to LTE and NR. When configured, transmitted, and received in separate circuits for different bands of LTE and NR, the LTE and NR sidelink synchronization signal offsets can be configured separately. When configuring a common synchronization signal offset between the LTE and NR sidelinks, at least one of the clusters for SLSS repetitions within the SLSS transmission period needs to be aligned with one of the SLSS offsets of the LTE sidelink. Also, depending on the UE capabilities, the base station can configure a common SLSS offset for the LTE and NR sidelinks. To indicate the common SLSS offset, the base station can configure an indicator of the common SLSS offset, or a reference RAT indicator, or a cross-carrier indicator, via SIB or RRC, to inherit the SLSS offset configured from one RAT to another RAT.

[0292] In one embodiment, when the SLSS repetitions are configured, the SLSS offset between NR and LTE may not be exactly aligned. The start time of at least one of the clusters for slot 0 of system frame number 0 can be the same as at least one of the LTE SLSS offsets.

[0293] All or some of the parameters configured by the base station in some embodiments or implementations can be pre-configured when the UE is outside the network coverage area.

[0294] In some embodiments or implementations, the UE may be replaced by a wireless device, and vice versa.

[0295] For example, a first wireless device may receive from a base station one or more configuration messages for indicating a demodulation reference signal (DMRS) configuration for a preemption signal, the preemption signal being transmitted to preempt one or more resources secured by a second wireless device, the first wireless device may transmit to the second wireless device one or more preemption signals having DMRS generated based on the DMRS configuration for preempting one or more resources secured by the second wireless device, the first wireless device may transmit one or more transport blocks on the one or more preempted resources, the one or more messages being radio resource control (RRC) or system information block (SIB), and the DMSS configuration includes at least one of the following: DMRS sequence initialization identity, DMRS resource element mapping, and DMSS period shift value. In this embodiment, the preemption signal is transmitted via a physical sidelink control channel, and the first and second wireless devices are performing sidelink communication.

[0296] In one embodiment, a first wireless device may receive a preemption signal from a second wireless device, the preemption signal including a physical sidelink control channel (PSCCH) that is repeatedly transmitted until it spans the same number of symbols as the number of physical sidelink shared channel (PSSCH) symbols in a slot, and the first wireless device may determine that the resources indicated by the preemption signal overlap with the resources reserved by the first wireless device, and based on the determination, the first wireless device may drop signal transmission on the resources reserved by the first wireless device. In this embodiment, the preemption signal includes at least one preemption resource information, the repetition of the PSCCH of the preemption signal has a predetermined redundancy version pattern, the first and second wireless devices perform sidelink communication, the first wireless device transmits one or more transport blocks at a first priority level, and the first priority level is less than a threshold. Further, the first wireless device may receive the threshold from a base station.

[0297] In one embodiment, a wireless device may receive, from a base station, conditions for preemption signal transmission, the first wireless device may determine whether preemption signal transmission is permitted based on the conditions, the first wireless device may transmit a preemption signal to preempt one or more resources based on the determination, and the first wireless device may transmit one or more transport blocks on one or more resources preempted by the preemption signal. In this embodiment, the conditions configured by the base station include all of the following: a target delay requirement threshold, a priority threshold, a reliability requirement threshold, and a target coverage threshold. Further, the preemption signal includes a physical sidelink control channel (PSCCH) that is repeatedly transmitted until it spans the same number of symbols as the number of physical sidelink shared channel (PSSCH) symbols in a slot.

[0298] In one embodiment, the wireless device can receive from the base station one or more configuration messages including a sidelink synchronization signal (SLSS) offset, the number of repetitions of the SLSS, and the subcarrier spacing (SCS) of the SLSS. And the wireless device can determine the size of the cluster of SLSS repetitions based on the SCS of the SLSS, and the wireless device can transmit the cluster within the number of times determined based on the number of repetitions and the size of the cluster during the SLSS transmission period. Here, the clusters are equally spaced within the SLSS transmission period. Also, the SLSS repetitions of each cluster are assigned to adjacent sidelink slots within the SLSS transmission period. In this embodiment, the sizes of the clusters for SCSs of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz are 1, 2, 4, 8, and 16 respectively, and the number of times of each cluster within the SLSS transmission period is determined by the highest value of the number of repetitions divided by the size of the cluster. Further, the wireless device may receive one or more configuration messages including the LTE SLSS offset, and at least one start time of the cluster with respect to slot 0 of system frame number 0 is the same as at least one of the LTE SLSS offsets.

[0299] According to various embodiments, devices such as, for example, wireless devices, off-network wireless devices, base stations, and / or the like can include one or more processors and a memory. The memory can store instructions that, when executed by the one or more processors, cause the device to perform a series of actions. Exemplary embodiments of the actions are illustrated in the accompanying figures and specification. Further embodiments can be created by combining features from various embodiments.

[0300] FIG. 43 is a flowchart according to one aspect of an exemplary embodiment of the present disclosure. At 4310, a first wireless device may receive, from a second wireless device, an indication of one or more first resources of a sidelink transport block and a priority of the sidelink transport block. At 4320, based on the priority and a priority threshold, the first wireless device may drop a sidelink transmission of one or more sidelink resources that overlap with the one or more first resources.

[0301] According to an exemplary embodiment, the indication may be indicated by sidelink control information. According to an exemplary embodiment, the sidelink control information may be received via a Physical Sidelink Control Channel (PSCCH). According to an exemplary embodiment, dropping the sidelink transmission of one or more second resources may include dropping the sidelink transmission of one or more third resources. According to an exemplary embodiment, one or more third resources may include one or more second resources that completely or partially overlap with one or more first resources. According to an exemplary embodiment, one or more third resources may include one or more subchannels within a sidelink resource pool. According to an exemplary embodiment, the priority threshold may be indicated by a base station. According to an exemplary embodiment, the first wireless device may receive, from the base station, a message indicating the priority threshold. According to an exemplary embodiment, the message may be received via a Radio Resource Control message. According to an exemplary embodiment, the message may be received via a System Information Block. According to an exemplary embodiment, the priority threshold may be preconfigured. According to an exemplary embodiment, the priority value may be smaller than the priority threshold. According to an exemplary embodiment, the first wireless device may transmit a first transport block via one or more fourth resources. For example, one or more fourth resources are non-overlapping resources of one or more first resources of one or more second resources. According to an exemplary embodiment, one or more fourth resources may include one or more subchannels within a sidelink resource pool. According to an exemplary embodiment, the priority threshold is for preemption of sidelink transmission. According to an exemplary embodiment, the first wireless device may receive, from the second wireless device, sidelink control information indicating one or more first resources and a priority. According to an exemplary embodiment, the sidelink transmission may be transmitted via one or more physical layer shared channels. According to an exemplary embodiment, one or more first resources may include one or more subchannels within a sidelink resource pool.According to an exemplary embodiment, one or more second resources may include one or more subchannels within a sidelink resource pool.

[0302] FIG. 44 is a flowchart according to one aspect of an exemplary embodiment of the present disclosure. At 4410, a first wireless device may transmit a cluster having a timing gap between each adjacent transmission of the cluster during a synchronization signal periodicity, the cluster including a repetition of a first number of sidelink synchronization signal blocks (SL-SSBs), and each of the clusters including a repetition of a second number of consecutive SL-SSBs.

[0303] According to an exemplary embodiment, the timing gap and the first number can be indicated by a message. According to an exemplary embodiment, the message can be received from a base station. According to an exemplary embodiment, the message can be an RRC message. According to an exemplary embodiment, the message can be an SIB. According to an exemplary embodiment, the second number can be indicated by a message. According to an exemplary embodiment, the message can be received from a base station. According to an exemplary embodiment, the message can be an RRC message. According to an exemplary embodiment, the message can be an SIB. According to an exemplary embodiment, the timing gap can be zero or more. According to an exemplary embodiment, the first radio device can receive one or more configuration messages including an SL-SSB offset. According to an exemplary embodiment, the first repetition of the SL-SSB starts from the SL-SSB offset. According to an exemplary embodiment, the first radio device can receive from a base station one or more configuration messages including an LTE sidelink synchronization signal (SLSS) offset. According to an exemplary embodiment, the SL-SSB offset can indicate the same time as the LTE SLSS offset. According to an exemplary embodiment, the second number can be determined based on the first number and the subcarrier spacing (SCS). According to an exemplary embodiment, the SCS can be indicated by a base station. According to an exemplary embodiment, the SCS can be preconfigured. According to an exemplary embodiment, the SCS can be indicated for a sidelink bandwidth part. According to an exemplary embodiment, the first radio device can transmit to one or more second radio devices. According to an exemplary embodiment, the SL-SSB may include a primary sidelink synchronization signal, a secondary sidelink synchronization signal, and a physical sidelink broadcast channel. According to an exemplary embodiment, the second number can be determined based on the subcarrier spacing (SCS) of the SL-SSB. According to an exemplary embodiment, the second number can be one of 1 for 15 kHz SCS, 2 for 30 kHz SCS, 4 for 60 kHz SCS, 8 for 120 kHz SCS, and 16 for 240 kHz SCS.According to an exemplary embodiment, the second number can be one of 1, 2, 4, 8, or 16.

[0304] FIG. 44 shows one aspect of an exemplary embodiment of the present disclosure. At 4410, a first wireless device transmits a cluster having a timing gap between each adjacent transmission of the cluster during a synchronization signal periodicity. The cluster includes a repetition of a first number of sidelink synchronization signal blocks (SL-SSBs). Each of the clusters includes a repetition of a second number of consecutive SL-SSBs.

Claims

1. receiving, from a base station, a message indicating a priority threshold for comparison with a priority of a sidelink control information (SCI) to be received from a first wireless device; The wireless device receives from the first wireless device: an indication of one or more first resources indicated by the SCI; an indication of the priority of the SCI; and dropping sidelink transmissions of one or more resources that overlap with the one or more first resources based on the priority and the priority threshold. The method includes:

2. 2. The method of claim 1, wherein the priority threshold is for preemption of the sidelink transmission.

3. 2. The method of claim 1, wherein dropping the sidelink transmission is further based on a priority level of the priority being less than the priority threshold.

4. The method of claim 1 , wherein the one or more resources overlap with the one or more first resources in a time domain and a frequency domain.

5. 2. The method of claim 1, wherein dropping the one or more resources further comprises dropping one or more second resources for the sidelink transmission.

6. The method of claim 5 , wherein the one or more second resources include the one or more resources that fully or partially overlap with the one or more first resources.

7. 6. The method of claim 5, wherein the one or more second resources comprise one or more sub-channels in a sidelink resource pool.

8. The method of claim 1 , wherein the message is received via a Radio Resource Control (RRC) message or a System Information Block (SIB).

9. 10. The method of claim 1, further comprising: transmitting a second sidelink transport block over one or more second resources, the one or more second resources being non-overlapping with the one or more resources that overlap with the one or more first resources.

10. 1. A wireless device, comprising: one or more processors; a memory storing instructions that, when executed by the one or more processors, cause the wireless device to: receiving, from a base station, a message indicating a priority threshold for comparison with a priority of a sidelink control information (SCI) to be received from a first wireless device; from the first wireless device, an indication of one or more first resources indicated by the SCI; an indication of the priority of the SCI; and dropping sidelink transmissions of one or more resources that overlap with the one or more first resources based on the priority and the priority threshold. Memory and Wireless devices including

11. The wireless device of claim 10 , wherein the priority threshold is for preemption of the sidelink transmission.

12. 11. The wireless device of claim 10, wherein the instructions further cause the wireless device to drop the sidelink transmission further based on a priority level of the priority being less than the priority threshold.

13. The wireless device of claim 10 , wherein the one or more resources overlap with the one or more first resources in a time domain or a frequency domain.

14. 11. The wireless device of claim 10, wherein the instructions further cause the wireless device to drop one or more second resources for the sidelink transmission.

15. 15. The wireless device of claim 14, wherein the one or more second resources include the one or more resources that fully or partially overlap with the one or more first resources.

16. 15. The wireless device of claim 14, wherein the one or more second resources include one or more subchannels in a sidelink resource pool.

17. The wireless device of claim 10 , wherein the message is received via a Radio Resource Control (RRC) message or a System Information Block (SIB).

18. 11. The wireless device of claim 10, wherein the instructions further cause the wireless device to transmit a second sidelink transport block over one or more second resources, the one or more second resources being non-overlapping with the one or more resources that overlap with the one or more first resources.

19. A non-transitory computer-readable storage medium comprising instructions that, when executed by one or more processors of a wireless device, cause the wireless device to: receiving, from a base station, a message indicating a priority threshold for comparison with a priority of a sidelink control information (SCI) to be received from a first wireless device; from the first wireless device, an indication of one or more first resources indicated by the SCI; an indication of the priority of the SCI; and dropping sidelink transmissions of one or more resources that overlap with the one or more first resources based on the priority and the priority threshold. A non-transitory computer-readable storage medium that causes

20. 20. The non-transitory computer-readable storage medium of claim 19, wherein the priority threshold is for preemption of the sidelink transmission.

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