A baseband processor for user equipment

Abstract

The present disclosure relates to a service device that can operate to generate sidelink communications with peer UE devices based on a PC5 unicast link to achieve direct peer-to-peer communications as part of PC5 vehicle-to-everything (V2X) communications. Radio state link detection can be configured via the PC5 unicast link based on a keep-alive (KA) coordination scheme to monitor the state of the PC5 unicast link. A KA timer can be configured via the PC5 unicast link based on the KA coordination scheme. The KA coordination scheme is configured to reduce redundant KA requests in the PC5 unicast link to coordinate the direct peer-to-peer communication across the PC5 unicast link.

Description

Technical Field

[0001] The present disclosure relates to wireless technologies, and more particularly to a vehicle-to-everything (V2X) device or similar device for a PC5 to remain activated. Background Art

[0002] Mobile communications in the next generation wireless communication system 5G or New Radio (NR) networks will provide ubiquitous connectivity and access to information and the ability to share data around the world. 5G networks and network slices will be unified, service-based frameworks that will target common and sometimes conflicting performance standards and provide services to extremely diverse application domains ranging from enhanced mobile broadband (eMBB) to massive machine type communications (mMTC), ultra-reliable low latency communications (URLLC) and other communications. In general, NR will evolve based on the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Advanced technology with additional enhanced radio access technologies (RATs) to achieve seamless and faster wireless connectivity solutions.

[0003] Some services have ultra-low latency, high data capacity and strict reliability requirements, because any failure or performance problem in the network can cause service failure, which in turn can cause property damage and physical injury. A type of mobile communication includes vehicle communication, in which vehicles transmit or exchange vehicle-related information. Vehicle communication may include vehicle-to-everything (V2X), which may include vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) and vehicle-to-pedestrian (V2P), etc., each of which may include user equipment (UE) or base station equipment such as new radio node B (gNB), eNodeB (eNB) or other equipment / node. For example, when V2X nodes are mentioned herein, the node may include new radio node B (gNB), eNodeB (eNB), user equipment (UE), roadside unit (RSU), drone or other vehicle equipment or network equipment. In some cases, vehicle-related information is intended for a single vehicle or other entity. In other cases (such as emergency alerts), vehicle-related information is intended for a large number of vehicles or other equipment entities. Emergency alerts may include collision warnings, loss of control warnings, collision avoidance, pedestrian safety, and other coordination to ensure safe and efficient traffic flow, especially in vehicle (e.g., cars, boats, drones, etc.)-to-vehicle communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] 1 is a block diagram illustrating an example of a user equipment (UE) communicatively coupled to a network component as a peer device via a network that may be used in conjunction with various embodiments (aspects) described herein.

[0005] Figure 2is a block diagram illustrating a system that can be employed at a UE according to various embodiments described herein.

[0006] Figure 3 is an exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0007] Figure 4 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0008] Figure 5 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0009] Figure 6 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0010] Figure 7 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0011] Figure 8 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0012] Fig. 9 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0013] Fig.10 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0014] Fig.11 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0015] Fig.12 is another exemplary block diagram for handling direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme in accordance with various embodiments described herein.

[0016] Fig.13is a block diagram illustrating an exemplary process flow for configuring direct peer-to-peer communications utilizing at least one PC5 unicast link for a KA coordination scheme according to various embodiments described herein.

[0017] Fig.14 A simplified block diagram of a user equipment wireless communication device or other network device / component is shown in accordance with various aspects described. DETAILED DESCRIPTION

[0018] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0019] The present disclosure will now be described with reference to the accompanying drawings, wherein throughout the text, similar figure numerals are used to refer to similar elements, and the structures and devices shown therein need not be drawn to scale. As used herein, the terms "component", "system", "interface", etc. are intended to refer to entities, hardware, software (e.g., in execution) and / or firmware related to a computer. For example, a component can be a processor (e.g., a microprocessor, a controller or other processing device), a process running on a processor, a controller, an object, an executable file, a program, a storage device, a computer, a tablet computer and / or a user equipment (e.g., a mobile phone, etc.) with a processing device. By way of example, an application program and a server running on a server can also be a component. One or more components can reside in a process, and a component can be located on a computer and / or distributed between two or more computers. This article can describe a set of elements or other component sets, wherein the term "set" can be interpreted as "one or more".

[0020] In addition, these components can be executed from various computer-readable storage media having various data structures stored thereon, such as using modules. Components can communicate via local and / or remote processes, such as according to signals having one or more data packets (e.g., data from one component interacts with another component in a local system, a distributed system, and / or an entire network, such as the Internet, a local area network, a wide area network, or a similar network with other systems via signals).

[0021] As another example, a component may be a device having a specific function provided by a mechanical component operated by an electrical or electronic circuit, wherein the electrical or electronic circuit may be operated by a software application or a firmware application executed by one or more processors. The one or more processors may be internal or external to the device and may execute at least a portion of the software or firmware application. As another example, a component may be a device that provides a specific function by electronic components without mechanical components; the electronic component may include one or more processors therein to execute at least a portion of the software and / or firmware that gives the electronic component its function.

[0022] The use of the word "exemplary" is intended to present concepts in a specific way. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X employs A or B" is intended to mean any natural inclusive arrangement. That is, if X employs A; X employs B; or X employs both A and B, then "X employs A or B" is satisfied in any of the foregoing cases. In addition, the articles "one" and "an" used in this application and the appended claims should generally be interpreted as meaning "one or more" unless otherwise specified or clear from the context to point to a singular form. In addition, to the extent that the terms "including", "comprising", "having", "having", "with" or variations thereof are used in the detailed description and claims, such terms are intended to be included in a manner similar to the term "comprising". In addition, in the case of discussing one or more numbered items (e.g., "first X", "second X", etc.), generally, one or more numbered items may be different or they may be the same, but in some cases, the context may indicate that they are different or that they are the same.

[0023] As used herein, the term "circuit" may refer to or include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) or associated memory (shared, dedicated, or group) operably coupled to a circuit that executes one or more software or firmware programs, a combinational logic circuit, or other suitable hardware component that provides the functionality, or a portion thereof. In some embodiments, the circuit may be implemented in one or more software or firmware modules or the functionality associated with the circuit may be implemented by one or more software or firmware modules. In some embodiments, the circuit may include a logic component that may operate at least partially in hardware.

[0024] In view of various issues for PC5 vehicle-to-everything UE communications (including direct peer-to-peer communications), a keep-alive coordination scheme can be enabled between various UEs via a PC5 unicast link. The UE can establish, configure or set a PC5 unicast link for PC5 V2X communication. Radio state link detection is performed via one or more UEs connected in the PC5 unicast link based on a keep-alive (KA) coordination scheme to monitor the state of the PC5 unicast link and the activities of peer devices communicatively coupled to the UE through the PC5 unicast link. The UE can configure its corresponding KA timer based on a specific KA coordination scheme. The KA coordination scheme reduces redundant KA requests in the PC5 unicast link to coordinate direct peer-to-peer communications across the PC5 unicast link and further avoid KA requests from conflicting or transmitting at the same time as each other.

[0025] The implementation scheme (aspect) includes a UE for establishing reliable radio link status detection using a KA coordination scheme via one or more protocol layers (e.g., access layer (AS), etc.). For the transmission (Tx) side (e.g., Tx-UE), even if hybrid automatic repeat request (HARQ) feedback is used, there is no guarantee that there is traffic on the PC5 unicast link for detection. In addition, HARQ feedback may be bound to a specific PC5 QoS flow and does not necessarily reflect the overall status of the PC5 unicast link. To address this issue, a mechanism and process flow for maintaining activation between UE-1 and UE-2 unicast links may be configured. UE-1 (or UE-2) may initiate a maintain activation request when a configured timer expires. The peer UE may respond with a KA confirmation (KA ACK). However, for the KA mechanism between peer UEs in PC5 V2X communications, several key functional issues and unique challenges remain. In the absence of coordination, because the respective timers of UE1 and UE2 may expire at the same time, they may initiate a maintain activation request together and then respond with a maintain activation confirmation. This may result in redundant PC5 signaling messages, which is inefficient for connecting the links.

[0026] Direct communication between vehicles and other devices (V2V, V2I) uses the so-called public or mission-critical (PC) 5 interface. PC5 refers to the reference point for a UE (V-UE, RSU, etc.) to communicate directly with another UE through a direct channel. In this case, there is no need to communicate with the base station. At the system architecture level, proximity services (ProSe) are features of the architecture that specify direct communication between UEs. In the 3GPP RAN specification, "sidelink" is a term that refers to direct communication through PC5. The PC5 interface was originally used to address the needs of mission-critical communications for the public safety community (public safety LTE or PS-LTE) in Release 13. The motivation for mission-critical communications is to allow law enforcement agencies or emergency rescue to use LTE communications even when infrastructure is unavailable (such as natural disaster scenarios). After Release 14, the use of the PC5 interface has been extended to meet various market needs, such as communications involving wearable devices such as smart watches. In C-V2X, the PC5 interface is reapplied to direct communications in V2V and V2I and other V-UEs. Additionally, unicast may refer to a one-to-one transmission from one point in a network to another; that is, one sender and one receiver, each of which may have a network address that uniquely identifies a single endpoint. Other aspects and details of the disclosure are further described below with respect to the accompanying drawings.

[0027] Figures 1A to 1C is a block diagram of a wireless communication network 100 in which wireless communication devices (e.g., user equipment (UE) devices) can use unicast, groupcast, and broadcast communications, according to, for example, one or more embodiments herein. Each device in the network includes vehicle-to-everything (V2X) circuitry 110, which includes memory storage and processing circuitry / components including one or more processors configured to perform various types of V2X communications. For purposes of this specification, when a "device" is described as performing some function, it is understood that it is a processor / component in the V2X device circuitry that is performing the function.

[0028] A transmitting (TX) device (e.g., Tx-UE or device 101) attempting to transmit data to one or more receiving (RX) devices in a wireless communication network first determines the sidelink channel resources available for this purpose. In Mode 1 (not shown), the TX device 101 requests sidelink channel resources from a manager device 100, which coordinates communications between devices in the network. The manager device 100 can be another UE device or a base station device (gNB, eNB, etc.). The manager device 100 provides downlink (DL) control information (DCI) or a permitted configuration of the sidelink configuration to the TX device, which identifies the specific sidelink channel resources to be used by it to transmit data. These specific sidelink channel resources are selected from a resource pool allocated to the network.

[0029] Depending on whether the TX device is to perform unicast, multicast, or broadcast transmission of data, the TX device determines (e.g., via higher layer signaling) a layer-1 destination identifier (L1 destination ID) that uniquely identifies one or more channels between the TX device 101 and a specific RX device (unicast identifier), a group of RX devices (multicast identifier), or all RX devices or Rx-UEs (broadcast identifier) ​​in the wireless communication network. In one example, the channel identified by the L1 destination ID is a physical sidelink control channel (PSCCH).

[0030] In Mode 2 ( Figures 1A to 1C As shown), TX device 101 selects sidelink channel resources to transmit data from a pre-allocated resource pool received a priori from a manager device or network component, rather than receiving a designation or allocation of specific sidelink communication resources from manager device 100.

[0031] exist Figure 1A In the unicast example of , the TX device 101 may be configured to transmit data to the RX device 102 and not to other devices. To enable this "direct" communication, the TX device 101 may initiate communication with the RX device 102 using a unicast L1 destination ID for the device 102. The TX device 101 uses the PSCCH resource associated with the L1 destination ID for the RX device 102 to send sidelink control information (SCI). The SCI indicates how the RX device 102 subsequently receives a transport block (TB) of data from the TX device 101. For example, the SCI includes a unicast L1 destination ID for the RX device 102 and identifies the frequency and time resources of the physical sidelink shared channel (PSSCH) that will be used to transmit (and in some cases retransmit) the TB. The SCI may also indicate whether the RX device provides feedback (such as an ACK / NACK indication) to confirm that the TB is received or to inform that the TB is not received. To this end, the SCI may include a hybrid automatic repeat request (HARQ) process identifier that uniquely identifies the TB for the RX device to use to provide feedback.

[0032] exist Figure 1BIn the multicast example of FIG. 1 , TX device 101 attempts to transmit data to group G, which includes several devices 102, 103, 104, and 105 (although there are only four devices in the group shown, there can be different numbers of devices in the group). The groupcast LI destination ID identifies the PSCCH channel for SCI monitored by the devices in group G. To enable multicast communication, TX device 101 determines the LI destination ID for group G. TX device 101 sends the SCI using the PSCCH resources associated with the LI destination ID for group G. The SCI instructs the devices in group G how to subsequently receive TBs from device 101. For example, the SCI includes the multicast L1 destination ID for group G and identifies the frequency and time resources of the physical sidelink shared channel (PSSCH) that is specified to be used for transmission and retransmission (in some cases) of TBs.

[0033] The SCI may indicate multicast options 1 or 2, which indicate whether and how the RX devices in group G provide feedback. In multicast option 1, when feedback is enabled, the only type of feedback provided by the RX device is NACK, and in some examples, when a particular RX device is outside the communication range specified in the SCI, the RX device does not provide any feedback. In multicast option 2, when feedback is enabled, the RX device provides both ACK / NACK feedback. The SCI may include a hybrid automatic repeat request (HARQ) process identifier that uniquely identifies the TB for the RX device to use to provide feedback.

[0034] exist Figure 1C In the broadcast example, the TX device 101 attempts to transmit data to all devices in the network. The broadcast L1 destination ID identifies the PSCCH channel for SCI that is monitored by all devices in the network. To enable broadcast communications, the device 101 determines the broadcast L1 destination ID for the network. The TX device 101 sends the SCI using the PSCCH resources associated with the broadcast L1 destination ID for the network. The SCI indicates how devices in the network can subsequently receive data from the device 101. For example, the SCI includes the broadcast L1 destination ID and identifies the frequency and time resources of the physical sidelink shared channel (PSSCH) that will be used to transmit and retransmit (in some cases) TBs.

[0035] Two modes of operation may be configured for V2X communications, namely, via PC5 and via LTE-Uu. LTE-Uu may be unicast or Multimedia Broadcast Service (MBMS). These two modes of operation may be used independently by the UE for transmission and reception (e.g., the UE may use MBMS for reception without using LTE-Uu for transmission). The UE may also receive V2X messages via the LTE-Uu unicast downlink. For both modes of operation, V2X devices (e.g., in different domains) may communicate with each other to exchange V2X messages. The interface between V2X application servers and the message exchange methods between V2X application servers are outside the scope of 3GPP.

[0036] refer to Figure 2 , which shows a block diagram of a system 200 that can be employed at a UE / V2X 101, UE 102, or a participating / peer entity 240 for direct peer-to-peer communication. The system 200 may include a processor 210, which includes processing circuits and associated interfaces (e.g., a communication interface for communicating with a communication circuit 220, a memory interface for communicating with a memory 230, etc.) and a communication circuit 220 (e.g., including circuits for wired and / or wireless connections, such as transmitter circuits (e.g., associated with one or more transmit chains) and / or receiver circuits (e.g., associated with one or more receive chains)). The transmitter circuits and receiver circuits of the transceiver 220 may employ common or different circuit elements or a combination thereof. The memory 230 may include any of a variety of storage media and may store instructions or data associated with one or more of the processor 210 or the communication circuit 220. In an embodiment, signaling or messaging between different embodiments of system 200 may be generated by processor 210, transmitted by communication circuitry 220 via a suitable interface or reference point (e.g., PC5, etc.), received by communication circuitry 220, and processed by processor 210.

[0037] When UE 101 is authorized to use V2X services over a 3GPP network, the UE may receive V2X configuration information. The authorization is done by a V2X function in the core network, and as part of the authorization process, the V2X function may send, for example, a list of preferred air interface technologies. Alternatively, V2X configuration may be performed by an application server that is not part of the core network. UE 101 may employ one or more channel quality measurements, such as power measurements or other measurements related to sidelink communications, for direct peer-to-peer communications.

[0038] A V2X UE may be located in a given coverage area within a cell covered by a gNB that supports 5G, LTE, and dedicated short range communication (DSRC) road side unit (RSU) functionality. These UEs 240 may inform the gNB / RSU which V2X communication radio access technology (RAT) is supported. Based on this information, the network may select an access technology for the UE to use. The system 200 includes a vehicle / traffic participant entity 240. The vehicle / traffic participant entity 240 includes one or more pedestrian devices (P-UE) 222, infrastructure entities 224 (e.g., RAN 120), vehicle entities 226, or other network devices / components. The V2X UE 101 may also include one or more antennas 208 for communication, including sidelink communications 214 with a vehicle / traffic participant entity or peer device 240.

[0039] The vehicle communication between the V2X-UE 101 and any vehicle / pedestrian device entity 240 can utilize cooperative sensing including information from other vehicles, sensors, etc. to process and share information to provide vehicle services such as collision warning, autonomous driving, etc. The V2X UE 101 is configured to obtain, select or determine the QoS attributes associated with the sidelink communication. The communication / communication configuration herein may include transmission resources, frame structure design, transmit power for broadcast (communication), subframe structure, modulation and coding scheme (MCS), number of occupied subchannels / transmission time interval (TTI), resource reservation interval / cycle, transmission range of each transmission block (TB), channel busy ratio (CBR), channel occupancy rate (CR), CR limit (CR_limit), associated LTE parameters in 3GPP, etc. For example, the frame structure has parameters including sampling rate, frame length, subframe length, subcarrier spacing and cyclic prefix length, and is based on the success rate obtained.

[0040] The sensing operation may be a simplified sensing process for V2X UE resource selection, aiming to reduce complexity and power consumption. In general, the principles of the sensing and resource selection process may be used for sidelink communication management. The resource (re)selection trigger utilized herein may include a resource reselection counter, a probabilistic reselection based on a probability of reselecting one or more resources, and one or more reselection trigger conditions, including whether the UE 101 skips transmission, for example, for a preconfigured / predetermined number of resource reservation periods. Specifically, modifications may be considered to the resource exclusion operation and the sidelink (SL) received signal strength indication (SL-RSSI) average or other sidelink channel indication for non-excluded resources. Such indications may, for example, provide information on whether a sidelink signal or a sidelink synchronization reference has been lost or is unavailable for initial sidelink synchronization.

[0041] Embodiments herein include various mechanisms including enhanced NR sidelink communication operations using PC5 unicast links 214 between UEs with components, configurations, or processes for resource allocation to enable device-to-device (D2D) communication or sidelink communication in one or more UEs 101, 102, V-UEs 226, or other networked devices 240 for direct communication between these devices. In PC5 V2X communication, there may be several different combinations between the source UE and the peer UE, including one or more of the following: V2V, V2P, V2I, RSU, or other UEs as UEs or V-UEs, which coordinate with each other as peers to participate in direct peer / sidelink communication. If there is no coordination, it may happen that both UE1 101 and UE2 102, for example, will initiate a keep-alive request 250 at the same time (or in succession) because their KA timers 232, 234 may expire at the same time. Then, both UEs will then have to respond to the peer's KA request with a Keep Alive Ack 252 to indicate that link 214 is still active. This can result in redundant PC5 signaling messages, which is desirable to avoid, and also results in redundant PC5 signaling on unicast link 214 or more unnecessary traffic.

[0042] Various KA coordination schemes may therefore be configured for optimal keep-alive procedures and efficiency over the PC5 unicast link 214 as a direct link to a single entity with a PC5 reference point. In one aspect, the UE 101 or 102 may define a KA initiator, which is a designated device that specifically initiates the KA request 250. Specifically, UE1 101 may be a device that initiates, sets up, or establishes a PC5 unicast link to UE2 102, and may therefore be designated as a KA initiator between peer devices (UE1 101 and UE2 102) over the PC5 unicast link 214.

[0043] When link 214 is inactive for a period of time, the KA operation at each UE comes into play to determine whether to keep link 214 active. Timers 232 and 234 of each UE are started, and if the timer (e.g., 232 of UE1 101) with a shorter timer value (e.g., x) expires first, a KA request is transmitted by UE1 101 over link 214. In response, the receiving UE (e.g., UE2 102) responds with a KA ACK 652 while stopping the timer 234 configured with a longer duration (e.g., x+y). If a KA request is not received when the longer timer value (e.g., x+y) expires, this may be considered a failure condition, and the UE (e.g., UE2 102) initiates a KA request in response to the timer expiration.

[0044] In one embodiment, UE1 101 and UE2 102 may determine whether UE1 101 or UE2 102 coupled to the PC5 unicast link operates as a KA request initiator to initiate one or more KA requests based on the source of the first PC5 message that establishes the direct link setup for the PC5 unicast link 214 or based on the last action that occurred on the PC5 unicast link, wherein the last action includes the reception or transmission of a PC5 message. Then, whichever UE device is designated as the KA request initiator, it provides a KA request 250 within a period of time or during the activation of the PC5 unicast link 214.

[0045] In one embodiment, the KA request may be initiated by the same UE (UE-1 or UE-2), based on who first initiated the first PC5 message to initiate the direct link establishment between UE1 101 and UE2 102 for direct peer-to-peer communication using the PC5 unicast link 214. This may be an implicitly defined designation of the KA initiator, for example, implied at setup time based on which device sends the first PC5 message over the PC5 unicast link 214, or this may be explicitly defined by including a new field "KA Initiator" in the direct link establishment request message or as the initial / first PC5 message. This will further clarify the situation and will not create confusion as to who will initiate the KA request 250. For example, if UE1 101 has initiated the direct link setup with UE2 (e.g., in so-called step 0 or step zero), the direct link 214 is established (in step zero). Regardless of which UE (UE1 101 or UE2 102) has initiated the initial setup step, that UE will be solely responsible for initiating the KA request as the initiator.

[0046] In one example, if UE1 101 initiates a direct link setup with UE2 102, the KA timers 232, 234 may be negotiated such that the timer 232 of UE1 101 is configured for "x" time units and the timer 234 of UE2 102 is configured for "x+y" time units. Thus, upon expiration or near expiration of x time units, UE1 101 transmits a KA request 250 over the PC5 unicast link 214. If UE2 102 obtains the KA request, it transmits a KA acknowledgement (ACK) 252 in response to the receipt. However, in the event of a failure / failure condition, such as the KA request 250 never arriving at UE2 102 within the expiration of the timer 234 of UE2 102 (e.g., x+y time units), UE2 102 is configured to transmit a KA request as a KA request initiator. In this case, when UE1 101 reaches a safety limit, fails, or is in a state where a KA request cannot be sent or reach UE2 102 , UE2 102 can still recover / maintain the link 214 and send a KA request based on the x+y time of its timer 234 .

[0047] y and x may be viewed as different amounts of time units (e.g., milliseconds, seconds, minutes, or other time units), where the KA timer 234 of the UE2 may be configured with an amount of time units of y time units that is greater than x time units. The KA timer 234 of the UE2 102 may be configured with y time units or with a function that ensures that the KA timer 234 is greater than x, such as x+y or any amount greater than x. Alternatively or additionally, y may be the same amount as x, but x+y is an amount greater than x, for configuring the KA timer 234 of the UE2 to ensure, for example, a recovery process.

[0048] Specifically, it may be agreed at the link setup via a PC5 signaling message or link setup signaling that the KA timer 234 of UE2 102 is configured to be longer than the timer 232. As part of step 0, for example, when the V2X link is set up as part of a PC5 signaling message, the time unit x of the timer 232 and the time unit x+y of the timer 234 may be entities that may be agreed or defined at this time. Thus, if UE1 101 initiates a direct link setup for the PC5 unicast link 214, UE1 101 will be the KA initiator providing a KA request at time unit x, and x may be any n time period unit, such as 1s, 5s, 10ms, or any other set of n time units.

[0049] refer to Figure 3 , which shows another example of a system 300 that can be employed at a UE / V2X 101, UE 102, or a participating / peer entity 240 in direct peer-to-peer communication according to another KA coordination scheme. Figure 2, UE1 101 and UE2 102 are configured to communicate via PC5 unicast link 214 to perform a KA coordination scheme, wherein a KA request 350 and a KA ACK 352 are sent over the PC5 unicast link 214 based on their corresponding KA timers 232 and 234 .

[0050] In another embodiment, the KA initiator may be determined based on a dynamic decision. The last action on the PC5 unicast link 214 may determine the KA initiator (e.g., transmission or reception of a signal or message), rather than the UE that initiated the link setup being authorized to initiate a KA request as a KA initiator via the PC5 unicast link 214. For example, a UE (e.g., UE2 102) whose last action was to transmit a PC5 message 348 may be designated / determined as a KA initiator to provide a KA request 350, either continuously (unless a failure / failure condition occurs) or initially in a KA coordination scheme.

[0051] As part of the UE1 101 to UE2 102 communication, there may be several PC5 messages 348 as signaling or user traffic. If the last interaction (message transfer) between the UEs was UE2 102 delivering or sending a message to UE1 101, for example, before the keep-alive procedure, UE2 102 as the KA initiator may initiate a KA request 350 to UE1 101. For example, the last action of UE2 102 may be a Tx of a V2X PC5 message (signaling or user traffic), and the last action of UE1 is a reception (Rx) of a V2X message, UE2 102 may initiate a KA request 350 and UE1 101 may respond with a KA ACK 352 to indicate that the link 214 is still active / activated. In this case, the timer 234 of UE2 102 may be configured to x, which is 10 seconds, and in this case of link 214 inactivity for 10 seconds, UE2 102 may go ahead and initiate the mechanism, because at this point which UE takes Tx as the last action, it may initiate the KA request 350. However, UE1 102 may have a timer configured to x+y time units, such as Figure 2 as described in the implementation scheme of .

[0052] This ensures coordination and ensures that UE2 102 (i.e., the UE that has transmitted the last Tx message) will have the opportunity to initiate the next KA message / request 350. This is useful in the following situations: any of these UEs (e.g., Figure 3UE 2 in the example 102) has a higher maximum transmission power limit (MTPL) as a Tx-UE, which means that the UE (e.g., UE2 102) will have a greater opportunity to transmit at a higher power, or the UE has a better battery / better RF resources, so it can then take the responsibility of initiating and transmitting the KA request 350. Alternatively or additionally, the UE with better RF resources or better backhaul resources can also take the responsibility of the KA request when due, which can be sensed, broadcasted, or known to the UE via link 214 or other means.

[0053] The reverse case of these UEs is also possible, where the KA timer can be negotiated such that UE-1 --> "x" time units, UE-2 --> "x+y" time units, as can be understood by those of ordinary skill in the art in the exemplary embodiments.

[0054] refer to Figure 4 , which shows another example of a system 400 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to another KA coordination scheme. Alternatively or additionally, the UE (e.g., UE1 101) whose last action is to receive the PC5 message 448 can be designated as a KA initiator to provide / initiate a KA request 450. In this embodiment, Figure 3 Since PC5 message 448 is being received by UE1 101 , as illustrated by receiving Rx over link 214 as the last action, UE1 101 will be the KA initiator sending KA request 450 to UE2 102 , which will respond with KA ACK 452 .

[0055] Thus, before the keep alive procedure, if the last action of UE1 101 or UE2 102 was Rx of a V2X PC5 message 448 (signaling or user traffic), the UE (e.g., UE1 101) will be agreed to have its KA timer (e.g., timer 232) set to x, while the KA timer of the other UE (e.g., timer 234 of UE2 102) is set to x+y. This implementation ensures coordination and ensures that the UE that has received the last PC5 unicast Rx message 448 will have the opportunity to initiate the next keep alive message or KA request 450. This may be useful in scenarios to ensure Tx / Rx fairness for the 2 UEs involved in V2V communication.

[0056] Figure 5An example is shown of another example of a system 500 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to another KA coordination scheme. The KA coordination scheme includes configuring a random value through random value generators 502 and 504 that are part of UE1 101 and UE2 102, respectively.

[0057] In this embodiment, the KA coordination scheme includes adding or subtracting the KA timer value of the KA timers 232 and 234 with random jitter. As described above, the same KA timer value may be agreed upon or configured as a time T, and once this is known, each UE (UE1 101, UE2 102) may generate a random value and add it to the KA timer value T for the KA timers 232 and 234. The random value generators 502 and 504 may be configured to generate a random value and provide the value for addition or subtraction in order to determine when UE1 101 and UE2 102 each operate to initiate or provide a KA request. Because the random value will be truly random, the random value selected by UE1 101 and UE2 102 is highly likely (greater than 99%) to be different from each other. For example, if the base timer value is T time units, each UE adds (adds or subtracts) the random value to the timer value of its timer (KA timer 232, 234) as T+ / -random value. This may further ensure that the KA timers 232 and 234 do not collide, and via the random jittered nonce value generation bias added to their keep alive timer values, one of the UEs will have a shorter KA timer upon KA request, while the other will have a longer KA timer. Additionally, UE1 101 and UE2 102 may continue to regenerate new nonce values ​​after each keep alive procedure.

[0058] Figure 6 Another example of a system 600 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to another KA coordination scheme is shown, which includes a round-robin KA scheme for a V2V UE or other UE communicatively coupled via a PC5 unicast link 214. The KA coordination scheme includes selecting a KA initiator in a round-robin mechanism.

[0059] For example, if the current KA request 650 (e.g., the nth request) is initiated by, for example, UE1 101 and sent to UE2 102, then the keep-alive timers 232 and 234 for the next KA procedure (n+1 requests) may be configured to be set to UE-1->"x+y" time units, UE-2->"x" time units. Request n may be any KA request within a sequence of KA requests over the PC5 unicast link between UE1 101 and UE2 102. Thus, for each round (e.g., first round 660, second round 662, etc.), the timer value may be switched, where, for example, the timer value of the timer 232 of UE1 101 in one round (e.g., round 660) is a longer duration (e.g., x+y), and the timer value of the timer 234 of UE2 102 is a longer duration (e.g., x+y) in the next round, and so on, for the duration that the link 214 between these UEs is active. This may ensure coordination and ensure that both UEs (eg, UE2 being the UE that received the last keep-alive request) may have an opportunity to initiate transmission of the next KA message / request 654 in a round-robin mechanism, etc.

[0060] When the link 214 is inactive for a period of time, the KA operation at each UE may start to act in order to determine whether to keep the link 214 in an active state. The timers 232 and 234 of each UE are started, and if the timer (e.g., 232 of UE1 101) with a shorter timer value (e.g., x) expires first, a KA request 650 is transmitted over the link 214. In response, the receiving UE (e.g., UE2 102) sends a KA ACK 652. This interaction may be a so-called round (e.g., round 660 or 662). However, for example, if the timer value (x+y) of the timer 234 of UE2 102 expires first without receiving the KA request 650, the KA request is transmitted instead of the KA ACK, which may be the result of a failure / failure condition. The failure condition may be caused by the inactivity of the link 214, a transmission failure of the UE1 101, or other resources that cannot make the KA request 650 reach the UE2 102 before the longer duration timer (e.g., x+y) expires.

[0061] In response to receiving a KA request 654 from UE2 102, for example because UE2 102 was the last to transmit a KA ACK 652, or because of the expiration of the timer value (x+y) of the timer 234, UE2 102 then transmits a KA request 656 as part of a different round 662 in the cyclic operation mechanism. In each subsequent round 660, the timer values ​​will be switched, with the timer 232 of UE1 101 now configured to have a value of x+y and the timer 234 of UE2 102 configured to have a value of x. A transition between a longer timer duration and a shorter timer duration may be initiated between the two UEs per round, either when a KA ACK is transmitted / received or when a KA request is made after the expiration of the longer timer (x+y). As long as the PC5 unicast link 214 is active, the longer timer should not expire. In the best case, it may happen that the UE configured with the timer x for a given round (e.g., 660, 662) expires first and initiates a KA request. The receiving UE then sends a KA ACK, and upon automatically sending the KA ACK, the UE will stop the longer timer of (x+y). For example, in each subsequent round (e.g., N+2, etc.), the timer value may be inverted / converted so that the next UE (now designated as the KA initiator) configures its timer to have x, while another UE configures its timer to have a longer duration of x+y.

[0062] The round-robin mechanism in the KA coordination scheme may be used, for example, to ensure fairness in Tx / Rx for the 2 UEs involved in V2V communication or direct peer-to-peer communication, and that, for example, KA Request / ACK is being exchanged instead of other traffic.

[0063] Figure 7 Another example of a communication flow in a KA coordination scheme 700 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to various embodiments over a PC5 unicast link 214 is shown. Figure 6 The KA coordination scheme of the cyclic KA scheme, Figure 7 A communication flow for a fault condition is shown and illustrates a fault mechanism that, for example, the UE may initiate or configure for corresponding timers 232 and 234 of the UE.

[0064] The KA coordination scheme 700 takes into account the handling of failure situations, where, for example, a KA request is not received when a longer timer value (e.g., x+y) expires, and the UE with the longer timer in this round initiates a KA request in response to the expiration of the timer. In this case, when the UE reaches a safety limit, fails, or is in a state where it cannot send a KA request or cannot make the KA request reach another peer UE, the peer UE can still recover / maintain the link 214 by sending a KA request based on the expiration of the x+y duration. In response to receiving a KA request from another peer UE, the UE that failed in the initial attempt to send the KA request responds with a KAACK within this round. If there is a failure situation or the KA request cannot reach another peer UE for at least two consecutive rounds, the other UE that successfully transmitted the KA request can assume the role of the KA initiator and continue to send the KA request. Therefore, both UEs accept by default a situation that one UE can only successfully obtain a KA confirmation via the PC5 unicast link 214, rather than a KA request. The size of the KA confirmation can be smaller than the size of the KA request and requires less power or resources to be transmitted over the PC5 unicast link 214.

[0065] For example, the first two rounds 660 and 662 of the round-robin scheme may be similar to Figure 6 KA communication, where UE1 101 may initiate a KA procedure at "x" configured as a timer value at timer 232 in a first round 660, and then UE-2 initiates the next KA procedure at a timer value 2*x as a timer 234 in a next round 662. y may be, for example, an amount equal to or less than x. Similarly, KA ACK 652 is transmitted by UE2 102 in response to KA request 650, and KA ACK 656 is transmitted by UE1 101 in response to KA request 654.

[0066] For example, a KA request 702 sent by UE1 101 experiences a failure condition. At this point, the KA request 702 fails to reach UE2 102 when its timer 3x+y expires. In response to the expiration of its timer 234, UE2 102, as the KA initiator for this round 764, sends a KA request 704. At this point, UE2's timer 234 will expire because the peer UE can always start the timer with an offset of y. For example, if UE1 101 had started at 3x, UE2 102 would start at 3x+y. Therefore, at this point, UE2 102 realizes that it will not get a KA request, and therefore initiates a KA request 704. In response to receiving the KA request 704, as part of round 764, UE1 101 responds, for example, with a KA ACK 706.

[0067] Because UE2 102 actually sends this KA request 708 at this time as part of the round robin mechanism in round 764, the next KA request 708 will be initiated by UE1 101 at 4x+y. Another round 766 begins with the KA initiator of that round (e.g., UE1 101) transmitting the KA request 708. However, once again, in the second consecutive round (e.g., round 766) as the KA initiator, UE1 101 fails to transmit a KA request (e.g., KA request 708) to its peer entity UE2 102 via the PC5 unicast link 214. UE2 102 then sends a KA request 710 when its timer value 4x+2y expires, thereby being responsible for initiating the KA request 710 due to the second consecutive round failure of its peer UE1 101. In response to receiving the KA request 710, UE1 101 responds with a KA ACK 712.

[0068] At this point, in the KA coordination scheme via the PC5 unicast link 214, the fail-safe mechanism is activated in response to at least two consecutive failures in a round in which UE1's KA request does not reach UE2 102. Therefore, UE1 101 is trying to initiate an uplink message including a KA request. However, UE1 101 can successfully send a KA ACK. This may mean that UE1 101 may have problems sending a larger message because the KA request is expected to be slightly larger than the KA ACK, which may be based on the fact that the KA request has a higher data content and the ACK is expected to be smaller. Therefore, after n consecutive failures (e.g., two or more rounds) as a KA initiator, UE2 102 assumes the role of a permanent KA initiator for the PC5 unicast link 214, thereby alleviating the burden of UE1 101 from further attempting KA requests over the link 214 and saving resources, for example temporarily or for the duration of the link 214. In other words, UE2 102 makes a decision to further initiate all future KA requests.

[0069] In one aspect, the decision of UE2 102 to act as a permanent KA initiator may also be communicated to UE1 101, since it may not be aware that UE2 102 has made this decision. The decision of a permanent KA initiator may be communicated in different ways. For example, it may be communicated explicitly in an additional field or as an additional / reserved bit via a KA request, or implicitly in another way, such as in a KA message / request. This field or entry may, for example, be used to indicate which entity will initiate the next KA request or the next few KA requests or initiate KA requests throughout the activation period of link 214. Alternatively, the explicit communication may be performed as part of a direct link modification procedure. Now UE1 101, for example, no longer initiates future KA requests in subsequent rounds (such as in 768), where, for example, KA request 714 is transmitted by UE2 102 as a permanent KA initiator. UE1 101 then only responds, such as with a KA ACK 716 in round 768, which may save resources.

[0070] Although the failure mechanism is demonstrated using the cyclic KA coordination scheme, the failure mechanism can also be applied to any of the other implementation schemes of the KA coordination scheme and is not limited to the above-mentioned Figure 6 The KA coordination loop mechanism was first introduced in .

[0071] Figure 8 Another example of a communication flow in a KA coordination scheme 700 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to various embodiments over a PC5 unicast link 214 is shown. Figure 6 The KA coordination scheme of the cyclic KA scheme, Figure 8 An embodiment is shown in which a cyclic stretching timer is configurable at timers 232 and 234 at each round of PC5 unicast link communication.

[0072] At this point, UE1 101 and UE2 102 may configure a telescoping timer mechanism in which a keep-alive initiator is selected in a round-robin manner, but each subsequent round may configure a larger base interval / KA time interval that will telescope or extend far beyond the initial shorter time value of x in each round as a telescoping or telescoping time interval unit. In peer devices communicatively coupled via the PC5 unicast link 214, the time value (base interval) of the KA initiator may also be a shorter time interval.

[0073] For example, if the current KA request 850 (e.g., the nth request in round 870) is initiated by UE1 101 and sent to UE2 102, which responds with KA ACK 852, then the keep-alive timers 232 and 234 of the next KA procedure round (n+1(a) request 856 of round 872) may be set such that the timer value of UE1 101 is configured according to (x*(n+1(a)))+y time units, and the timer value of UE2 102 is configured according to (x*(n+1(a))) time units. Thus, the index n+1, n+2, etc. of each round may be used as a telescoping interval or time by which the base interval of each KA initiator's timer (corresponding to the timer 232 or timer 234 of the UE device) is extended. Alternatively or additionally, α(a) may be further utilized or not utilized in each round, which may also further extend or adjust, for example, the weight of the current index of a given round. α may be, for example, any function, variable, or constant.

[0074] Subsequently, for the (n+2) request 860 of round 874, the keep-alive timers 232 and 234 may be set such that UE-1->"(x*(n+2(a)))" time units, UE-2->"(x*(n+2(a)))+y" time units. Each KA request 850, 854, and 858 is responded to with a corresponding KA ACK message 852, 856, and 860 accordingly.

[0075] The telescoping mechanism may further operate to ensure coordination and ensure that the UE that received the previous keep-alive request will have the opportunity to initiate the transmission of the next keep-alive message as the KA initiator. Additionally or alternatively, the mechanism may continue to increase the keep-alive interval based on the attempt count or attempts to send a KA request.

[0076] In another embodiment, the telescoping interval may be a different base interval / KA interval with which the timers 232 and 234 are configured. For example, each of the timers 232 and 234 may include a periodic timer every 10 seconds. The second timer may be configured as a telescoping timer, where the timer is configured for 10 seconds in the first round, and if this is successful, the next round is, for example, 20 seconds later, then a round after 70 seconds, the next round after 150 seconds, and so on. Thus, the interval increase may also be based on the successful receipt of one or more KA requests.

[0077] Fig. 9Another example of a communication flow in a KA coordination scheme 900 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to various embodiments is shown. Here, UE2 102 may be, for example, a V2I or a road side unit (RSU).

[0078] In one embodiment, for PC5, the RSU 102 may be connected to a power source, primarily an infrastructure. Therefore, the UE1 101 and the RSU 102 may include a mechanism as part of a KA coordination scheme via the PC5 unicast link 214 to ensure that the RSU is always the KA initiator that initiates the transmission of a KA request (e.g., KA Request 950), with the UE1 101 responding only with a KA ACK 952.

[0079] Generally, in a V2X unicast PC5 link, if one entity 240 (e.g., cellular device, etc.) is connected to a power source (as opposed to a battery or related device) and the other peer entities are not connected, then the UE connected to the power source should be responsible for initiating the KA request 950, not necessarily based on, for example, whether one peer entity is an RSU or a V2I device. This can be achieved by the UE connected to the power source having a lower keep alive timer 232 compared to the peer UE timer 234, or vice versa. The type of device or connection to the power source may also be transmitted or predefined, for example.

[0080] Fig.10 Another example of a communication flow in a KA coordination scheme 1000 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to various embodiments is shown. UE1 101 may also include an implicit KA ACK timer 1002, and UE2 102 may include an implicit KA ACK timer 1004.

[0081] In an embodiment, instead of just responding to a KA request 1050 from UE1 101 with a KA ack from UE2 102 (or vice versa), UE2 102 may transmit a signal or message (e.g., PC5 message 1052) in its queue or storage device 230 (if queued therein) instead of a KA ACK. Thus, instead of a KA ACK, if UE2 102 sends some valid PC5 signaling or traffic message, for example, after receiving the KA request 1050 and before sending the KA ACK, this may be considered an implicit KA ACK to UE1 101. UE1 101 may consider the link 214 to still be active. Furthermore, UE-1 will not expect an explicit KA ACK.

[0082] The implicit KA ACK timers 1002 and 1004 may be set to reduce redundant KA ACKs and may be started at UE2 102 (or the receiving UE of the KA request) once UE2 102 receives the KA request 1050 from UE1 101 and prevent the sending of KA ACK before the expiration of the timer 234. In addition, UE2 102 may send KA ACK when the implicit KA ACK timer 1004 expires. However, before the implicit KA ACK timer 1004 expires, if there is any valid PC5 signaling or user traffic message to be sent from UE2 102 to UE1 101, UE2 102 may stop the implicit KA ACK timer 1004 and send the valid PC5 message instead of sending KA ACK.

[0083] At least one benefit of the KA coordination scheme 1000 may be that it provides an opportunity to reduce the need to send a KA ACK if there is any pending valid PC5 traffic that would be sent anyway, thereby providing an opportunity for valid traffic to be sent while also functioning as an implicit KA ACK.

[0084] refer to Fig.11 , which is another example of a communication flow in a KA coordination scheme 1100 that can be employed at a UE / V2X 101, UE 102, or participating / peer entity 240 in direct peer-to-peer communication according to various embodiments.

[0085] In one embodiment, in addition to or as an alternative to inactivity, a KA request may be initiated in response to one or more triggers. The trigger may be, for example, a lower layer failure detection (e.g., a link layer of a protocol stack or a lower layer including a PHY layer). For example, any kind of link layer or layer 1, physical layer problem (e.g., a high level or threshold for a block error rate (BLER) or error rate at layer 1 or lower layer detection 1148 failure is met, low signal strength, a power measurement / level drops below a threshold or otherwise meets a threshold, or a very low signal strength less than a threshold, or other such lower layer failure detection). In response to the detection 1148, a KA request 1150 may be initiated by UE1 101 or UE2 102. In addition to or as an alternative to the expiration of a timer of a timer value x or x+y, this may provide an active mechanism for initiating a KA request 1150, for example, to keep the PC5 unicast link 214 in an activated / active state.

[0086] exist Fig.11In the example of , UE1 101 may detect a link failure or a drop below or a signal measurement that satisfies a threshold measurement of the strength of the PC5 unicast link 214 at 1148. UE1 101 may then be triggered to provide a KA request 1150. In response to the KA request 1150, UE2 102 responds with a KA ACK 1152. In this case, UE1 101 receives the KA ACK 1152, and UE1 101 may determine that although the link 214 may be poor, it still maintains a communication link valid with the peer UE2 102. However, if the peer UE2 102 does not respond, there may still be an active mechanism that is triggered via an additional triggering mechanism and does not require waiting for the timer mechanism 232 to expire, regardless of the time unit configured for the timer mechanism. In this way, UEs that conduct direct peer communications via the PC5 unicast link 214 may actively consider or estimate the active feasibility of the link, and when the keep-alive procedure does not obtain a successful ACK, the UE may actively consider that the link has stopped functioning. In contrast, for example, if the KA request does obtain a successful KA ACK, the UE may consider that the PC5 unicast link is still valid and not disconnect the link itself based on detection 1148 and send a KA request or receive a KA request.

[0087] refer to Fig.12 , which is another example of a communication flow in a KA coordination scheme 1100 that can be employed at participating / peer entities 240 (e.g., UE2, UE3, and UE4) in direct peer-to-peer communication according to various embodiments. The KA coordination scheme may include multiple peer entities 240, such as UE2, UE3, and UE4, each of which has a PC5 unicast link 1204 connected to UE1 101 for PC5 messaging. In various scenarios, UE1 101 may have multiple connections, especially in commercial V2X deployments, where there may be multiple active PC5 unicast links (e.g., UE1 to UE2, UE1 to UE3, UE1 to UE4, etc.).

[0088] If UE1 101 initiates a unicast KA request with each peer entity (UE2, UE3 and UE4) individually, that could be a lot of signaling. Therefore, in such a scenario, a "single broadcast" "keep alive" request / message 1202 may be generated via broadcast messaging instead of sending several unicast KA requests. It may be broadcast or multicast, for example, as a single message to all UEs that have a PC5 unicast link to UE1 101. This single broadcast / multicast message may be sent by UE1 101 when the keep alive timer 232 expires or is about to expire for multiple PC5 unicast links. Therefore, UE1 101 may only send a broadcast keep alive or multicast keep alive or groupcast keep alive as a single message and send to all UEs that are near PC5 or have a PC5 unicast link 1204 with UE1 101, instead of sending a separate message to each UE.

[0089] Based on receiving the broadcast / multicast / groupcast keep alive request 1202 from UE1 101, the peer UEs (UE2, UE3, and UE4) may then decide to respond to UE1 101 with a unicast KA ACK (e.g., 1250, 1252, 1254) to let UE-1 know which of these UEs (UE2, UE3, and UE4) has an active PC5 unicast link 1204. For example, UE1 101 may send a broadcast 1202, and only UE2 and UE3 respond with KA ACK 1250 and 1252. UE1 101 may then know that the UE1 to UE4 PC5 unicast link is disconnected and take mitigation measures or re-establish the link 1204 with UE4.

[0090] In one embodiment, for the case where the broadcast message 1202 is lost and does not reach the destination (e.g., UE4), a timer called T keep alive retransmission or "Tka retransmission" 1232 may be configured. At this time, if UE1 101 still has not received a keep alive ack when the Tka-retransmission timer expires, UE1 will resend the keep alive request as a unicast message to each individual peer UE or UE from which it did not receive a KA ACK due to the broadcast KA request 1202. For example, if UE1 101 sends a broadcast to UE-2-3-4 and only UE 2 and 3 (via the corresponding PC5 unicast link 1204) respond with KA ACK 1250 and 1252, and then the timer Tka retransmission expires at UE1 101, at this time UE1 101 may attempt to resend the keep alive request in unicast 1204 over the corresponding individual PC5 unicast link for the request to UE-4. Then, if UE-4 still does not respond, it will attempt to reestablish or tear down the link. However, if UE4 does receive the KA request 1254 over the PC5 unicast link with UE1 101 as a standalone unicast link 1204, UE4 may respond with a KA ACK (not shown) via the unicast link 1204 to remain active in direct peer-to-peer communications with its peer UE1 101.

[0091] The broadcast V2X message 1202 at layer 2 may be sent via radio link control (RLC) unacknowledged mode (UM), while the unicast V2X message may be sent via RLC acknowledged mode (AM). This means that in AM, the Ack / Nack may be transmitted at the layer 2 link layer, rather than having to be transmitted at the keepalive layer. However, this is where the broadcast message may not reach the destination, and even the source of the KA request may not be aware of it because there is no ACK. Therefore, the broadcast message may not reach the destination, such as in the case of UE4. In this case, in the event that the broadcast keepalive message 1202 reaches the peer UE (which is a good case), the KA ACK will be received by UE1 because the KA ACK is still received via RLC-AM because the ACK can be received over the air. For the case where the broadcast message 1202 is lost and does not reach the destination, a timer 1232 is specifically configured for broadcast 1202. At this point, if UE1 still has not received the KA ACK when the Tka-retransmission timer expires, UE1 101 may resend one or more KA requests as unicast messages to each individual peer UE via each individual PC5 unicast link 1204 there, or only to the peer entities that did not respond to the broadcast KA request.

[0092] Alternatively or additionally, UE2, UE3, or UE4 may decide to broadcast or multicast or groupcast KA ACK instead of transmitting KA ACK via corresponding PC5 unicast link 1204 in response to receiving broadcast KA request 1202. Thus, the UE transmits a KA message including KA request, KA ACK, or both via unicast or broadcast. For example, in response to UE2 and UE3 receiving KA request 1202, each of them may decide to broadcast KA ACK, for example, as an activation message (e.g., "I am active"), or send KA ACK via their respective unicast links, and UE-1 may consider the PC5 link from UE-1 to UE2 to be active, for example, based on receiving the I am active indication from UE-2.

[0093] Based on receiving the broadcast keep alive request 1202 from UE-1-UE2, UE3 and UE4 may choose to respond to UE-A or UE2 with a unicast KA ACK, or UE3, UE4 may further decide to broadcast an "I am active" indication. Based on the "I am active" broadcast indication received from UE-2, UE-1 may consider the PC5 link from UE-1 to UE-2 to be active. By intelligently utilizing the broadcast function in the KA coordination scheme described herein, this mechanism helps reduce the amount of PC5 maintenance messages required.

[0094] Although the method described in the present disclosure is shown and described as a series of actions or events in this article, it should be understood that the order of such actions or events shown should not be interpreted as having a limiting meaning. For example, some actions can occur in different orders and / or simultaneously with other actions or events other than those shown and / or described herein. In addition, all the actions shown may not be required to implement one or more aspects or embodiments of this specification. In addition, one or more actions in the actions depicted herein may be performed in one or more separate actions and / or stages. For ease of description, reference may be made to the above-mentioned accompanying drawings. However, the method is not limited to any specific embodiment or example provided in the present disclosure, and may be applied to any system in the system disclosed herein.

[0095] refer to Fig.13 , which illustrates an exemplary process flow 1300 for a network device or component (eg, UE 101 or other network component) to perform operations for direct peer-to-peer communications between UE peer devices.

[0096] At 1310, process flow 1300 begins by generating or processing PC5 messages for direct peer-to-peer communications over a PC5 unicast link.

[0097] At 1320 , process flow 1300 also includes configuring a keep-alive (KA) coordination scheme to reduce redundant or concurrent KA requests via the PC5 unicast link and monitor the status of the PC5 unicast link.

[0098] At 1330 , process flow 1300 includes configuring a KA timer based on the KA coordination scheme.

[0099] In another embodiment, the process flow may include establishing a direct link setup of a PC5 unicast link via PC5 messages.The KA request initiator may be configured to provide one or more KA requests over the PC5 unicast link based on having initiated establishment of the PC5 unicast link.

[0100] Alternatively or additionally, in response to being the last device to transmit or receive a PC5 message over the PC5 unicast link, a first KA request may be provided within x value time units of the KA timer. The process flow may include receiving a KA confirmation (ACK) in response to the KA request, or receiving a second KA request in response to expiration of y value time units greater than x value time units associated with a KA timer of another peer UE of the PC5 unicast link.

[0101] In another embodiment, the processing flow may include providing a KA request via a PC5 unicast link based on a trigger, the trigger comprising at least one of: expiration of a KA timer or detection of a fault related to an access layer / link layer or lower layers of the protocol stack, wherein the fault comprises satisfying a threshold of at least one of: a block error rate (BLER), a noise level, a signal power, or a link parameter.

[0102] In another embodiment, the process flow may include broadcasting or multicasting a KA request in response to a plurality of PC5 unicast links being active, and receiving one or more KA ACKs via one or more of the plurality of PC5 unicast links based on the broadcasted KA request. The embodiment may also include resending the KA request via at least one of the plurality of PC5 unicast links in response to a T-KA-retransmission timer expiring before receiving a KA ACK from at least one of the plurality of PC5 unicast links.

[0103] Alternatively or additionally, the process flow may include broadcasting a broadcast KA request in response to the plurality of PC5 unicast links being active, or independently transmitting the plurality of KA requests through the plurality of PC5 unicast links. The process flow may also include receiving one or more KA ACKs based on the broadcast KA request or the plurality of KA requests via one or more of the plurality of PC5 unicast links, or receiving one or more activation indications in one or more broadcast messages based on the broadcast KA request or the plurality of KA requests.

[0104] refer to Fig.14 , which shows a block diagram of a user equipment wireless communication device (UE) or other network device / component (e.g., UE1, UE2, UE3, UE4 or other participating entity) configured to perform direct peer-to-peer communication according to various aspects described herein. The UE device 1400 may include: one or more processors 1410 (e.g., one or more baseband processors), including processing circuits and associated interfaces; transceiver circuits 1420 (e.g., including RF circuits, which may include transmitter circuits (e.g., associated with one or more transmit chains) and / or receiver circuits (e.g., associated with one or more receive chains), which may use common circuit elements, different circuit elements, or a combination thereof); and a memory 1430 (which may include any of a variety of storage media and may store instructions and / or data associated with one or more of the processors 1410 or the transceiver circuits 1420).

[0105] In various embodiments (aspects) discussed herein, signals and / or messages may be generated and output for transmission, and / or the transmitted messages may be received and processed. Depending on the type of signal or message generated, output for transmission (e.g., by processor 1410, processor 1410, etc.) may include one or more of the following operations: generating a set of associated bits encoding the content of the signal or message; encoding (e.g., may include adding a cyclic redundancy check (CRC) and / or encoding via a turbo code, a low-density parity check (LDPC) code, a tail-biting convolutional code (TBCC), etc.); scrambling (e.g., based on a scrambling seed); modulation (e.g., via one of binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), or some form of quadrature amplitude modulation (QAM), etc.); and / or resource mapping (e.g., mapping to a scheduled resource set, mapping to a time and frequency resource set authorized for uplink transmission, etc.). Depending on the type of signal or message received, processing (e.g., by processor 1410) may include one or more of the following operations: identifying physical resources associated with the signal / message, detecting the signal / message, resource element group deinterleaving, demodulating, descrambling and / or decoding.

[0106] As used in this specification, the term "processor" may refer to substantially any computing processing unit or device, including but not limited to single-core processors; single processors with software multithreaded execution capabilities; multi-core processors; multi-core processors with software multithreaded execution capabilities; multi-core processors with hardware multithreading technology; parallel platforms; and parallel platforms with distributed shared memory. In addition, a processor may refer to an integrated circuit, an application-specific integrated circuit, a digital signal processor, a field programmable gate array, a programmable logic controller, a complex programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions and / or processes described herein. The processor may utilize nanoscale architectures, such as, but not limited to, molecular and quantum dot-based transistors, switches, and gates, in order to optimize space usage or enhance the performance of a mobile device. The processor may also be implemented as a combination of computing processing units.

[0107] Examples (implementations) may include subject matter such as methods, devices for performing actions or boxes of the methods, and at least one machine-readable medium comprising instructions that, when executed by a machine (e.g., a processor with memory, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc.), cause the machine to perform actions of a method or device or system for concurrent communication using multiple communication technologies according to the embodiments and examples described herein.

[0108] The first example is a device adopted in a user equipment (UE), wherein the device includes: a processing circuit, wherein the processing circuit is configured to: enable direct peer communication using a PC5 unicast link for PC5 vehicle-to-everything (V2X) communication; generate a radio state link detection via the PC5 unicast link based on a keep-alive (KA) coordination scheme to monitor the state of the PC5 unicast link; and configure a KA timer via the PC5 unicast link based on the KA coordination scheme, wherein the KA coordination scheme is configured to reduce redundant KA requests in the PC5 unicast link to coordinate the direct peer communication across the PC5 unicast link.

[0109] A second example may include the first example, wherein the processing circuit is further configured to: initiate a direct link setup of the PC5 unicast link by generating a first PC5 message on the PC5 unicast link; and in response to providing the first PC5 message to generate the direct link setup of the PC5 unicast link, operate as a designated KA request initiator to provide any KA request over the PC5 unicast link for the keep-alive coordination scheme.

[0110] A third example may include the first example or the second example, wherein the processing circuit is further configured to: provide a KA request via the PC5 unicast link based on one or more triggers, the one or more triggers including at least one of the following: expiration of the KA timer or detection of a fault related to the access layer / link layer or lower layer of the protocol stack, wherein the fault includes a threshold that satisfies at least one of the following: block error rate (BLER), noise level, signal power, or link parameters.

[0111] A fourth example may include any one or more of the first to third examples, wherein the processing circuit is further configured to: determine a KA request initiator that initiates one or more KA requests between the UE and the peer UE based on whether the transmission or reception of the most recent PC5 message in time is associated with the UE or with a peer UE of the PC5 unicast link.

[0112] The fifth example may include any one or more of the first to fourth examples, wherein the processing circuit is further configured to: in response to providing a KA request, a KA confirmation, or establishment of a direct link setup via the PC5 unicast link: generate a random value via a random value generator; and add or subtract the random value from the T value time unit of the KA timer to determine the expiration for another KA request or another KA confirmation.

[0113] The sixth example may include any one or more of the first to fifth examples, wherein the processing circuit is further configured to: configure a first round of the KA cycle process of the KA coordination scheme in the following manner: based on an x ​​numerical time unit associated with the KA timer, provide a first KA request as a KA initiator through the PC5 unicast link; and receive a first KA ACK through the PC5 unicast link in response to the first KA request; configure a second round of the KA cycle process of the KA coordination scheme in the following manner: receive a second KA request via the PC5 unicast link based on y numerical time units greater than the x numerical time units using the KA timer; and provide a second KA ACK through the PC5 unicast link in response to the second KA request.

[0114] The seventh example may include any one or more of the first to sixth examples, wherein the processing circuit is further configured to: provide a KA request via the PC5 unicast link; determine whether the PC5 unicast link includes an active link based on at least one of the following: a KA confirmation (ACK) or an implicit KA ACK indication including any valid PC5 message or user traffic message via the PC5 unicast link; and stop the KA timer based on the PC5 unicast link including the active link.

[0115] The eighth example may include any one or more of the first to seventh examples, wherein the processing circuit is further configured to: receive a KA request via the PC5 unicast link; start a KA ACK wait timer in response to receiving the KA request; and generate a KAACK via the PC5 unicast link in response to expiration of the KA ACK wait timer, or generate a PC5 signal / user traffic message on the PC5 unicast link before the KA ACK wait timer expires, and stop the KA ACK wait timer to allow the PC5 signal / user traffic message to be an implicit KA ACK indication in response to the KA request.

[0116] A ninth example is a computer-readable storage device storing executable instructions that, in response to execution, cause one or more processors of a vehicle user equipment (V-UE) to perform operations, the operations comprising: generating or processing PC5 messages for direct peer-to-peer communication via a PC5 unicast link; configuring a keep-alive (KA) coordination scheme to reduce redundant or concurrent KA requests via the PC5 unicast link and monitoring the status of the PC5 unicast link; and configuring a KA timer based on the KA coordination scheme.

[0117] The tenth example may include the ninth example, wherein the operation further includes: establishing a direct link setup of the PC5 unicast link via the PC5 message; and based on the established PC5 unicast link, operating as a KA request initiator to provide one or more KA requests through the PC5 unicast link.

[0118] The eleventh example may include any one or more of the ninth to tenth examples, wherein the operation further includes: providing a first KA request within x numerical time units of the KA timer in response to being the last device to transmit or receive the PC5 message through the PC5 unicast link; and receiving a KA confirmation (ACK) in response to the KA request, or receiving a second KA request in response to the expiration of y numerical time units greater than x numerical time units associated with the KA timer of another peer UE of the PC5 unicast link.

[0119] The twelfth example may include any one or more of the ninth to eleventh examples, wherein the operation further includes: providing a KA request via the PC5 unicast link based on a trigger, the trigger comprising at least one of the following: expiration of the KA timer or detection of a fault related to the access layer / link layer or lower layer of the protocol stack, wherein the fault comprises a threshold that satisfies at least one of the following: block error rate (BLER), noise level, signal power, or link parameters.

[0120] The thirteenth example may include any one or more of the ninth to twelfth examples, wherein the operation further includes: broadcasting a KA request in response to multiple PC5 unicast links being active; and receiving one or more KA ACKs via one or more PC5 unicast links among the multiple PC5 unicast links based on the broadcasted KA request.

[0121] The fourteenth example may include any one or more of the ninth to thirteenth examples, wherein the operation further includes: in response to expiration of the T-KA-retransmission timer before receiving a KA ACK from at least one PC5 unicast link among the multiple PC5 unicast links, resending the KA request via the at least one PC5 unicast link among the multiple PC5 unicast links.

[0122] The fourteenth example may include any one or more of the ninth to thirteenth examples, wherein the operation also includes: broadcasting a broadcast KA request in response to multiple PC5 unicast links being active, or independently transmitting multiple KA requests through the multiple PC5 unicast links; and receiving one or more KA ACKs based on the broadcast KA request or the multiple KA requests via one or more of the multiple PC5 unicast links, or receiving one or more activation indications in one or more broadcast messages based on the broadcast KA request or the multiple KA requests.

[0123] The sixteenth example is a system for direct peer-to-peer communication between peer user equipment (UE), the system comprising: a first UE, the first UE comprising a first keep-alive (KA) timer and a first processing circuit; wherein the processing circuit of the first UE is configured to transmit a PC5 message via a PC5 unicast link for the direct peer-to-peer communication with a second UE, and enable a keep-alive (KA) coordination scheme to reduce redundant or concurrent KA requests via the PC5 unicast link and configure the KA timer.

[0124] The seventeenth example may include the sixteenth example, wherein the processing circuit is further configured to: generate a determination of whether the first UE or the second UE coupled to the PC5 unicast link operates as a KA request initiator to initiate one or more KA requests based on at least one of the following items: the source of the first PC5 message for the direct link setup for the PC5 unicast link or the last action occurring on the PC5 unicast link is from the first UE or the second UE, wherein the last action includes reception or transmission of the PC5 message; and provide a KA request based on the determination of the KA request initiator.

[0125] The eighteenth example may include any one or more of the sixteenth to seventeenth examples, wherein the processing circuit is further configured to: rotate the designation of a KA request initiator that provides a KA request via the PC5 unicast link between the first UE and the second UE according to a cyclic process, wherein the cyclic process changes the designation of the KA initiator between the first UE and the second UE in a round of the cyclic process in response to the first UE or the second UE receiving a KA ACK or an additional KA request in place of the KA ACK.

[0126] The nineteenth example may include any one or more of the sixteenth to eighteenth examples, wherein the processing circuit is further configured to: extend the activation interval at subsequent rounds of the round of the cyclic process by an incremental value or a function multiplied by a time unit value configured for the KA timer of the first UE and another timer of the second UE.

[0127] The twentieth example may include any one or more of the sixteenth to nineteenth examples, wherein the processing circuit is further configured to: generate a fail-safe operation that fixes the designation of the KA request initiator between the rounds in response to receiving the additional KA request instead of the KA ACK in at least two consecutive rounds during the loop.

[0128] The twenty-first example may include any one or more of the sixteenth to twenty-third examples, wherein the second UE includes a vehicle-to-infrastructure (V2I) UE or a road side unit (RSU), the road side unit being coupled to a power source as a permanent power source, and the first UE being configured to enable the second UE to operate as a KA initiator, the KA initiator providing one or more KA requests via the PC5 unicast link in response to being coupled to the power source using a lower timer than the first UE.

[0129] The embodiments (aspects or examples) of this document may include, together or separately, a layer-2 link maintenance procedure through the PC5 reference point as the KA process / operation discussed herein, including at least: 0. Unicast link setup; 1. KA request; 2. KA ACK.

[0130] The PC5 signaling protocol supports a keep-alive function for detecting whether a particular PC5 unicast link (or PC5 link / message passing link) is still valid. Either side of the PC5 unicast link (e.g., link 214, etc.) may initiate a layer-2 link maintenance procedure (i.e., a keep-alive procedure) based on, for example, a trigger from the AS layer or an internal timer. The UE (e.g., UE1 101 or any peer participant 240) may operate to minimize keep-alive signaling (e.g., 1. cancel the procedure if data is successfully received over the PC5 unicast link; 2. implicitly or explicitly coordinate to ensure that the chance of keep-alive conflicts (e.g., redundant or concurrent KA requests on the link) is reduced).

[0131] Some implementations to consider are (e.g. 1. the UE initiating the direct link establishment procedure may be configured with a smaller timer, while the peer UE may be configured with a larger timer; 2. both UEs may independently generate a randomly generated value and add it to the timer value or their respective timer values).

[0132] It may be further studied whether the keep-alive timer values ​​may be exchanged in the direct link establishment procedure. This may also depend on the range of the random value. The direct link establishment may include: 0. UE-1 and UE-2 have a unicast link established as described in clause 6.3.3.1 of TS 23.287 of 3GPP Release 16 or higher; 1. Based on a trigger condition, UE-1 sends a keep-alive message to UE-2 to determine the state of the PC5 unicast link; 2. After receiving the keep-alive message, UE-2 responds with a keep-alive Ack message. The exact trigger for the keep-alive message (KA request / confirmation) and the implementation of the present disclosure may be further studied. For example, the trigger may be based on a timer associated with a layer-2 link. Another trigger may be based on a deteriorated lower layer link condition (e.g., high BLER, etc.). The timer may be reset using a successful reception event defined by TS38.300.

[0133] The UE initiating the keep-alive procedure may determine subsequent actions based on the result of the signaling, such as continuing with the implicit layer-2 link release. For example, in the case of timely reception, a successful reception event may also cancel the layer-2 link release.

[0134] In addition, various aspects or features described herein may be implemented as methods, devices or articles using standard programming and / or engineering techniques. As used herein, the term "article" is intended to cover computer programs accessible from any computer-readable device, carrier or medium. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips, etc.), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs), etc.), smart cards, and flash memory devices (e.g., EPROMs, cards, sticks, key drives, etc.). In addition, the various storage media described herein may represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and / or carrying instructions and / or data. In addition, a computer program product may include a computer-readable medium having one or more instructions or codes that are operable to cause a computer to perform the functions described herein.

[0135] Communication media embodies computer readable instructions, data structures, program modules, or other structured or unstructured data in a data signal such as a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery or transmission medium. The term "modulated data signal" or signal refers to a signal that has one or more of its characteristics set or changed in a manner that encodes information in one or more signals. By way of example, and not limitation, communication media include wired media such as a wired network or direct wired connection, and wireless media such as acoustic, RF, infrared and other wireless media.

[0136] An exemplary storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium. In an alternative, the storage medium may be integrated with the processor. In addition, in some aspects, the processor and the storage medium may reside in an ASIC. In addition, the ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in a user terminal as discrete components. In addition, in some aspects, the process and / or action of the method or algorithm may reside on a machine-readable medium and / or a computer-readable medium as one or any combination or set of codes and / or instructions, and the machine-readable medium and / or the computer-readable medium may be incorporated into a computer program product.

[0137] In this regard, although the subject matter disclosed in the present invention has been described in conjunction with various embodiments and corresponding drawings, it should be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments to perform the same, similar, alternative or alternative functions of the disclosed subject matter without departing from the described embodiments. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, but should be interpreted according to the breadth and scope of the following claims.

[0138] In particular, with respect to the various functions performed by the above-mentioned components (assemblies, devices, circuits, systems, etc.), unless otherwise specified, the terms used to describe such components (including references to "means") are intended to correspond to any component or structure that performs the specified function of the component (e.g., functionally equivalent), even if not structurally equivalent to the disclosed structure that performs the function in the exemplary implementation of the present disclosure shown herein. In addition, although specific features have been disclosed with respect to only one of several implementations, for any given or specific application, such features may be combined with one or more other features of other implementations, which may be desirable and advantageous.

[0139] appendix

[0140] The embodiments (aspects or examples) of this document may include, together or separately, a layer-2 link maintenance procedure through the PC5 reference point as the KA process / operation discussed herein, including at least: 0. Unicast link setup; 1. KA request; 2. KA ACK.

[0141] The PC5 signaling protocol supports a keep-alive function for detecting whether a particular PC5 unicast link (or PC5 link / message passing link) is still valid. Either side of the PC5 unicast link (e.g., link 214, etc.) may initiate a layer-2 link maintenance procedure (i.e., a keep-alive procedure) based on, for example, a trigger from the AS layer or an internal timer. The UE (e.g., UE1 101 or any peer participant 240) may operate to minimize keep-alive signaling (e.g., 1. cancel the procedure if data is successfully received over the PC5 unicast link; 2. implicitly or explicitly coordinate to ensure that the chance of keep-alive conflicts (e.g., redundant or concurrent KA requests on the link) is reduced).

[0142] Some implementations to consider are (e.g. 1. the UE initiating the direct link establishment procedure may be configured with a smaller timer, while the peer UE may be configured with a larger timer; 2. both UEs may independently generate a randomly generated value and add it to the timer value or their respective timer values).

[0143] It may be further studied whether the keep-alive timer values ​​may be exchanged in the direct link establishment procedure. This may also depend on the range of the random value. The direct link establishment may include: 0. UE-1 and UE-2 have a unicast link established as described in clause 6.3.3.1 of TS 23.287 of 3GPP Release 16 or higher; 1. Based on a trigger condition, UE-1 sends a keep-alive message to UE-2 to determine the state of the PC5 unicast link; 2. After receiving the keep-alive message, UE-2 responds with a keep-alive Ack message. The exact trigger for the keep-alive message (KA request / confirmation) and the implementation of the present disclosure may be further studied. For example, the trigger may be based on a timer associated with a layer-2 link. Another trigger may be based on a deteriorated lower layer link condition (e.g., high BLER, etc.). The timer may be reset using a successful reception event defined by TS38.300.

[0144] The UE that initiated the keep-alive procedure may determine subsequent actions based on the result of the signaling, such as continuing the implicit layer-2 link release. Subsequent actions may also be further determined. For example, in the case of timely reception, the successful reception event may also cancel the layer-2 link release.

Claims

1. A baseband processor for user equipment, the baseband processor being configured to perform operations when executing instructions stored in a memory, the operations comprising: Communicate using PC5 unicast links for PC5 vehicle-to-everything V2X communications; configuring a keep-alive coordination scheme to monitor the status of the PC5 unicast link; as well as Configuring a keep-alive timer based on the keep-alive coordination scheme includes generating a random value via a random value generator, and adding or subtracting the random value from a keep-alive timer value.

2. The baseband processor of claim 1, wherein the operations further comprise: initiating a direct link setup of the PC5 unicast link by generating a first PC5 message for transmission on the PC5 unicast link; as well as In response to providing the first PC5 message to generate the direct link setup for the PC5 unicast link, operating as a designated keepalive request initiator by providing any keepalive request over the PC5 unicast link for the keepalive coordination scheme.

3. The baseband processor of claim 1 , wherein the operations further comprise: A keep-alive request is provided via the PC5 unicast link based on one or more triggers, the one or more triggers comprising at least one of: expiration of the keep-alive timer or detection of a fault related to an access layer / link layer or a lower layer of a protocol stack, wherein the fault comprises a threshold satisfying at least one of: a block error rate (BLER), a noise level, a signal power or a link parameter.

4. The baseband processor of claim 1, wherein the operations further comprise: A keepalive request initiator is determined to initiate one or more keepalive requests between the user equipment and the peer user equipment based on whether the most recent transmission or reception of a PC5 message in time is associated with the user equipment or a peer user equipment of the PC5 unicast link.

5. The baseband processor of claim 1 , wherein generating a random value and adding or subtracting the random value is responsive to providing a keep-alive request, a keep-alive confirmation, or an establishment of a direct link setup via the PC5 unicast link, and wherein the operations further comprise: An expiration for another keep-alive request or another keep-alive confirmation is determined based on the keep-alive timer.

6. The baseband processor of claim 1, wherein the operations further comprise: The keep-alive cycle process of the keep-alive coordination scheme is performed in the following manner: In response to expiration of the keep-alive timer, providing a first keep-alive request for transmission over the PC5 unicast link; receiving a first keep-alive confirmation via the PC5 unicast link in response to the first keep-alive request; configuring a second keep-alive timer having a duration greater than the keep-alive timer; receiving a second keep-alive request via the PC5 unicast link before expiration of the second keep-alive timer; and A second keep alive acknowledgement is provided for transmission over the PC5 unicast link in response to the second keep alive request.

7. The baseband processor of claim 1, wherein the operations further comprise: providing a keep-alive request for transmission over the PC5 unicast link; determining whether the PC5 unicast link comprises an active link based on at least one of: a keep-alive confirmation or an implicit keep-alive confirmation indication including any valid PC5 message or user traffic message via the PC5 unicast link; as well as The keep-alive timer is stopped based on the PC5 unicast link comprising the active link.

8. The baseband processor of claim 1, wherein the operations further comprise: receiving a keep-alive request via the PC5 unicast link; starting a keep-alive confirmation wait timer in response to receiving the keep-alive request; as well as Generate a keep-alive confirmation for transmission over the PC5 unicast link in response to expiration of a keep-alive confirmation wait timer, or generate a PC5 signal / user traffic message on the PC5 unicast link before expiration of the keep-alive confirmation wait timer, and stop the keep-alive confirmation wait timer to allow the PC5 signal / user traffic message to serve as an implicit keep-alive confirmation indication in response to the keep-alive request.

9. A computer-readable storage device storing executable instructions that, in response to being executed, cause one or more processors of a vehicle user equipment to perform operations comprising: Generate or process PC5 messages for direct peer-to-peer communications via a PC5 unicast link; configuring a keep-alive coordination scheme to monitor the status of the PC5 unicast link; configuring a first keep-alive timer based on the keep-alive coordination scheme; providing a first keep-alive request in response to expiration of the first keep-alive timer and the vehicle user equipment being the last device to transmit or receive the PC5 message over the PC5 unicast link; and A keep alive confirmation is received in response to the keep alive request, or a second keep alive request is received in response to expiration of a second keep alive timer having a duration greater than the first keep alive timer, wherein the second keep alive timer is associated with a peer user equipment of the PC5 unicast link.

10. The computer readable storage device of claim 9, wherein the operations further comprise: establishing a direct link setup of the PC5 unicast link via the PC5 message; as well as Based on the PC5 unicast link being established, operating as a keepalive request initiator by providing one or more keepalive requests via the PC5 unicast link.

11. The computer readable storage device of claim 9, wherein the operations further comprise: The first stay-alive request is provided via the PC5 unicast link based on detecting a failure related to an access layer / link layer or a lower layer of a protocol stack, wherein the failure comprises satisfying a threshold of at least one of: a block error rate (BLER), a noise level, a signal power, or a link parameter.

12. The computer readable storage device of claim 9, wherein the operations further comprise: broadcasting the first keep-alive request in response to a plurality of PC5 unicast links being active; as well as One or more keep alive confirmations are received via one or more PC5 unicast links of the plurality of PC5 unicast links based on the broadcast keep alive request.

13. The computer readable storage device of claim 12, wherein the operations further comprise: In response to a T-keep-alive-retransmission timer expiring before receiving the keep-alive confirmation from at least one PC5 unicast link among the multiple PC5 unicast links, resending the first keep-alive request via the at least one PC5 unicast link among the multiple PC5 unicast links.

14. The computer readable storage device of claim 9, wherein the operations further comprise: In response to the plurality of PC5 unicast links being in an active state, broadcasting a broadcast keep-alive request, or independently transmitting a plurality of keep-alive requests through the plurality of PC5 unicast links; as well as Receiving one or more keep-alive confirmations via one or more PC5 unicast links among the multiple PC5 unicast links based on the broadcast keep-alive request or the multiple keep-alive requests, or receiving the one or more keep-alive confirmations in one or more broadcast messages based on the broadcast keep-alive request or the multiple keep-alive requests.

15. A system for direct peer-to-peer communication between peer user equipments, the system comprising: a first user equipment, the first user equipment comprising a processing circuit, the processing circuit being configured to: transmit a PC5 message with a second user equipment via a PC5 unicast link for the direct peer-to-peer communication, configure a keep-alive coordination scheme to monitor a status of the PC5 unicast link, and configure a keep-alive timer based on the keep-alive coordination scheme; The system is configured to rotate the designation of a keep-alive request initiator that provides a keep-alive request via the PC5 unicast link between the first user equipment and the second user equipment according to a process, wherein the process changes the designation of the keep-alive initiator between the first user equipment and the second user equipment in rounds of the process in response to the first user equipment or the second user equipment receiving a keep-alive confirmation or an additional keep-alive request in place of the keep-alive confirmation.

16. The system of claim 15, wherein the processing circuit is further configured to: generating a determination of whether the first user equipment or the second user equipment coupled to the PC5 unicast link operates as the keepalive request initiator to initiate one or more keepalive requests based on at least one of the following: a source of a first PC5 message for a direct link setup for the PC5 unicast link or a last action occurring on the PC5 unicast link from the first user equipment or the second user equipment, wherein the last action comprises receipt or transmission of the PC5 message; and A keep-alive request is provided based on the determination of the keep-alive request initiator.

17. The system of claim 15, wherein the processing circuit is further configured to: A keep alive interval is extended at a subsequent round of the round of the process by an increment value or a function multiplied by a time unit value configured for the keep alive timer of the first user equipment and another timer of the second user equipment.

18. The system of claim 15, wherein the processing circuit is further configured to: A fail-safe operation is generated that fixes the designation of the keep-alive request initiator between the rounds in response to receiving the additional keep-alive request in place of the keep-alive confirmation in at least two consecutive rounds in the process.

19. The system of claim 16, wherein the second user equipment comprises a vehicle-to-infrastructure (V2I) user equipment or a roadside unit (RSU) coupled to a power source, the power source being a permanent power source, and the first user equipment being configured to enable the second user equipment to operate as the keep-alive request initiator, the keep-alive request initiator providing one or more keep-alive requests via the PC5 unicast link using a lower timer than the first user equipment in response to being coupled to the power source.

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