Communication method and apparatus

Abstract

Provided in the present disclosure are a communication method and an apparatus, relating to the technical field of communications. The communication method comprises: in response to the signal quality of at least one candidate cell satisfying a first handover condition before an RLF occurs, performing a handover to a target cell, or performing a handover to the target cell after the RLF has occurred, the target cell being a cell among the at least one candidate cell.

Description

Communication methods and devices

[0001] Cross-reference of related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202411929387.9, filed in China on December 24, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of communication technology, and in particular to a communication method and apparatus. Background Technology

[0004] Radio Link Failure (RLF) refers to a situation where the wireless link is interrupted during communication due to various reasons. The RLF procedure is triggered when the quality of the wireless link between the terminal device and the network device deteriorates to the point that normal communication cannot be maintained.

[0005] In existing technologies, after an RLF occurs, a Radio Resource Control (RRC) reconstruction process is usually initiated. That is, after an RLF occurs, the terminal device will select a cell and rebuild in the selected cell (i.e., the target cell). The target cell needs to obtain the terminal device's context from the original cell before it can restore the configuration and transmit data. Summary of the Invention

[0006] This disclosure provides a solution for improving communication efficiency by performing cell handover in advance or in a timely manner in the event of a potential RLF (Recurrent Leakage Fault).

[0007] To achieve the above objectives, this disclosure provides the following technical solutions:

[0008] In a first aspect, a communication method is provided, comprising: performing a handover to a target cell in response to the signal quality of at least one candidate cell satisfying a first handover condition before a radio link failure (RLF) occurs, or performing a handover to the target cell after an RLF occurs, wherein the target cell is a cell among the at least one candidate cell.

[0009] Optionally, the occurrence of an RLF may include one or more of the following events: the RLF timer starts or expires, the expiration of the RLF timer indicating the occurrence of an RLF; or receiving N consecutive out-of-step instructions, where N is a positive integer.

[0010] Optionally, the RLF timer includes timer T310 or timer T312.

[0011] Optionally, the step of performing a handover to the target cell in response to the signal quality of at least one candidate cell satisfying the first handover condition before an RLF occurs includes: in response to the start of the RLF timer, evaluating the signal quality of one or more candidate cells, wherein the at least one candidate cell is a cell among the one or more candidate cells; and performing a handover to the target cell in response to the signal quality of the at least one candidate cell satisfying the first handover condition.

[0012] Optionally, the step of performing a handover to the target cell in response to the signal quality of at least one candidate cell satisfying the first handover condition before an RLF occurs includes: in response to receiving N consecutive out-of-synchronization indications, evaluating the signal quality of one or more candidate cells, wherein the at least one candidate cell is a cell among the one or more candidate cells, and N is a positive integer; and performing a handover to the target cell in response to the signal quality of the at least one candidate cell satisfying the first handover condition.

[0013] Optionally, the step of performing a handover to the target cell in response to the signal quality of at least one candidate cell satisfying the first handover condition before an early RLF occurs includes: starting an RLF timer in response to the signal quality of the at least one candidate cell satisfying the first handover condition; and performing a handover to the target cell in response to the expiration of the RLF timer, wherein the expiration of the RLF timer indicates that an early RLF has occurred.

[0014] Optionally, the communication method further includes: reporting a measurement report in response to the signal quality of the at least one candidate cell satisfying the first handover condition.

[0015] Optionally, performing a handover to the target cell after an RLF occurs includes: in response to an RLF, selecting the target cell and performing a handover to the target cell, wherein the signal quality of the at least one candidate cell meets the signal quality required by the first handover condition before the RLF occurs, and the duration for which the signal quality required by the first handover condition is met does not reach a first duration.

[0016] Optionally, the communication method further includes: receiving first information, wherein the first information indicates whether early switching is permitted.

[0017] Optionally, the communication method further includes: receiving configuration information, the configuration information being used to indicate the first switching condition and the second switching condition, the second switching condition being used to trigger condition switching when not in RLF mode.

[0018] Optionally, the configuration information includes the second switching condition and the first switching condition; or, the configuration information includes the second switching condition and the offset between the first switching condition and the second switching condition.

[0019] Optionally, the target cell is the cell with the best signal quality among the at least one candidate cell, or the cell whose signal quality satisfies the signal quality required by the first handover condition for the longest duration.

[0020] Secondly, this disclosure also discloses a communication method, which includes: performing a handover of a terminal device to a target cell before or after an RLF occurs, wherein the target cell is a cell among at least one candidate cell, and the signal quality of the at least one candidate cell satisfies a first handover condition before the RLF occurs.

[0021] Optionally, the communication method further includes: sending configuration information, the configuration information being used to indicate the first switching condition and the second switching condition, the second switching condition being used to trigger condition switching when not in RLF.

[0022] Optionally, the configuration information includes the second switching condition and the first switching condition; or, the configuration information includes the second switching condition and the offset between the first switching condition and the second switching condition.

[0023] Thirdly, this disclosure also discloses a communication device, comprising: a communication module, configured to perform a handover to a target cell in response to a first handover condition being met by at least one candidate cell before an RLF occurs, or to perform a handover to the target cell after an RLF occurs, wherein the target cell is a cell among the at least one candidate cell.

[0024] Fourthly, this disclosure also discloses a communication device, comprising: a communication module, configured to perform a handover of a terminal device to a target cell before or after an RLF occurs, wherein the target cell is a cell among at least one candidate cell, and the signal quality of the at least one candidate cell satisfies a first handover condition before the RLF occurs.

[0025] Fifthly, a computer-readable storage medium is provided having a computer program stored thereon, the computer program being executed by a processor to perform any one of the methods provided in the first or second aspect.

[0026] In a sixth aspect, a communication device is provided, including a memory and a processor, wherein the memory stores a computer program executable on the processor, and the processor executes the computer program to perform any of the methods provided in the first aspect.

[0027] In a seventh aspect, a communication device is provided, including a memory and a processor, wherein the memory stores a computer program executable on the processor, and the processor executes the computer program to perform any of the methods provided in the second aspect.

[0028] Eighthly, a computer program product is provided, on which a computer program is stored, the computer program being executed by a processor to perform any one of the methods provided in the first or second aspect.

[0029] Ninthly, a communication system is provided, including the aforementioned terminal equipment and the aforementioned network equipment.

[0030] In a tenth aspect, embodiments of this disclosure also provide a chip that stores a computer program, which, when executed by the chip, implements the steps of the above-described method.

[0031] Eleventhly, embodiments of this disclosure also provide a system chip for use in a terminal device. The system chip includes at least one processor and an interface circuit. The interface circuit and the at least one processor are interconnected via a line. The at least one processor is used to execute instructions to perform any one of the methods provided in the first or second aspect. Attached Figure Description

[0032] Figure 1 is an interactive flowchart of a communication method provided in an embodiment of this disclosure;

[0033] Figure 2 is an interactive flowchart of another communication method provided in an embodiment of this disclosure;

[0034] Figure 3 is a schematic diagram of the RLF timer provided in an embodiment of this disclosure;

[0035] Figure 4 is an interactive flowchart of another communication method provided in an embodiment of this disclosure;

[0036] Figure 5 is a schematic diagram of a communication configuration provided in an embodiment of this disclosure;

[0037] Figure 6 is a schematic diagram of the hardware structure of a communication device provided in an embodiment of this disclosure. Detailed Implementation

[0038] The communication systems applicable to the embodiments of this disclosure include, but are not limited to, Long Term Evolution (LTE) systems, 5th-generation (5G) systems, New Radio (NR) systems, and future evolution systems or multiple converged communication systems. The 5G system can be a non-standalone (NSA) 5G system or a standalone (SA) 5G system. The technical solutions of this disclosure are also applicable to different network architectures, including but not limited to relay network architectures, dual-connectivity architectures, and vehicle-to-everything (V2X) communication architectures.

[0039] This disclosure primarily relates to communication between terminal devices and network devices. Specifically:

[0040] The network device in this disclosure embodiment can also be called an access network device, for example, a base station (BS) (also called a base station device). A network device is a device deployed in a radio access network (RAN) to provide wireless communication functions. For example, in second-generation (2G) networks, the equipment providing base station functionality includes base transceiver stations (BTS); in third-generation (3G) networks, it includes nodes (NodeB); in fourth-generation (4G) networks, it includes evolved nodes (eNB); in wireless local area networks (WLANs), the equipment providing base station functionality is access points (APs); and in NR, the equipment providing base station functionality includes next-generation node base stations (gNBs) and further evolved nodes (ng-eNBs). gNBs and terminal devices communicate using NR technology, while ng-eNBs and terminal devices communicate using evolved universal terrestrial radio access (E-UTRA) technology. Both gNBs and ng-eNBs can connect to the 5G core network. The network device in this disclosure also includes devices that provide base station functionality in future new communication systems.

[0041] In this disclosure, "terminal equipment" can refer to various forms of access terminals, user units, user stations, mobile stations, mobile stations (MS), remote terminals, mobile devices, user terminals, wireless communication devices, user agents, or user devices. Terminal equipment can also be cellular phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDAs), handheld devices with wireless communication capabilities, computing devices, or other processing devices connected to a wireless modem, in-vehicle devices, wearable devices, terminal equipment in future 5G networks, or terminal equipment in future evolved Public Land Mobile Networks (PLMNs), etc. This disclosure does not limit the scope of these examples. Terminal equipment can also be referred to as User Equipment (UE), terminal, etc.

[0042] To facilitate understanding of the technical solutions disclosed herein, a brief introduction to the relevant technologies involved in this disclosure will be given first.

[0043] Currently, NR introduces Conditional Handover (CHO). Conditional handover refers to a handover performed by the terminal device when handover conditions (which may include one or more measurement events) are met. This prevents the terminal device from failing to complete the handover due to drastic signal changes or weak signal strength (for example, if the terminal device detects drastic or weak signal strength changes in the network device, the original network device may not be able to issue a handover command to the terminal device in time, thus preventing the terminal device from completing the handover). Optionally, the terminal device measures the serving cell and its neighboring cells and reports the measurement results. Based on the measurement results reported by the terminal device, the Centralized Unit (CU) or network device configures one or more candidate cells (or alternative cells) and their related configurations, as well as the handover conditions. When the handover conditions are met, the terminal device directly hands over to the target cell (which is one of the candidate cells). The terminal device initiates a random access procedure in the target cell, sends an RRC reconfiguration completion message, and then can notify the original network device to release the terminal device's connection.

[0044] Optionally, the handover conditions may include relevant event assessments based on signal quality such as Reference Signal Receiving Power (RSRP), Reference Signal Receiving Quality (RSRQ), and Signal to Interference plus Noise Ratio (SINR). The handover event in the handover conditions may be event A3, event A4, or event A5.

[0045] Among them, event A3 indicates that the signal quality of the neighboring cell exceeds the signal quality of the primary cell of a master or secondary cell group (Spcell) by a certain offset. Event A4 indicates that the measurement result of the neighboring cell is greater than a threshold. Event A5 indicates that the signal quality of the Spcell is lower than threshold 1, while the signal quality of the neighboring cell is higher than threshold 2. In addition to meeting the corresponding signal quality conditions, these events also require that the relevant signal quality conditions be met continuously within the time to trigger (TTT).

[0046] Optionally, the measurement results in the different events mentioned above are all Layer 3 (L3) measurement results. The L1 measurement results need to be filtered by L3 before they can be used to determine whether the triggering conditions required by the event are met.

[0047] Layer 1 measurement refers to measurement operations performed at the physical layer (PHY layer), primarily used for real-time monitoring and evaluation of the radio channel status. Layer 1 measurement results refer to the outcomes obtained from Layer 1 measurements. Layer 3 measurement, on the other hand, involves filtering the obtained Layer 1 measurement results by the RRC layer. Unlike Layer 1 measurements (physical layer measurements), Layer 3 measurements are mainly used for long-term channel quality assessment and mobility management, such as cell handover, reselection, and load balancing. Layer 3 measurement results refer to the outcomes obtained from Layer 3 operations.

[0048] Optionally, the L1 measurement results may include measurement results for at least one of the following: Received Signal Strength Indicator (RSSI), RSRP, RSRQ, SNR, SINR, Bit Error Rate (BER), Channel State Information (CSI), etc.

[0049] In subsequent discussions, a Layer 1 / Layer 2-triggered Mobility (LTM) handover triggered by Layer 2 (L2) signaling based on L1 measurement results was introduced. In this process, L1 measurement results are reported periodically or triggered by network devices. This may result in multiple reports even when handover conditions (e.g., the aforementioned handover events) are not met, wasting reporting resources and potentially failing to report L1 measurement results in a timely manner. Therefore, event-triggered measurement reporting based on L1 measurement results was introduced. That is, when the L1 measurement results obtained by the terminal device meet certain conditions, a measurement report is triggered to notify the network device. Current L1 measurement events include: LTM Event 2, LTM Event 3, LTM Event 4, and LTM Event 5.

[0050] LTM event 2 indicates that the serving cell's beam quality is below absolute threshold 1. LTM event 3 indicates that the candidate cell's beam quality exceeds the preset offset of the serving cell's beam quality. LTM event 4 indicates that the candidate cell's beam quality is above absolute threshold 2. LTM event 5 indicates that the serving cell's beam quality is below absolute threshold 1, and the candidate cell's beam quality is above absolute threshold 2.

[0051] Furthermore, when a terminal device detects a wireless link problem (such as low signal strength, inability to decode the control channel, or loss of synchronization), it will start a corresponding timer, such as timer T310. Specifically, T310 will be started when the RRC layer receives N310 consecutive loss of synchronization indications from the physical layer (N310 is configured by the network; if the network is not configured, the default value can be used). If the wireless link problem is not resolved before the timer expires, for example, if it does not receive N311 consecutive synchronization indications from the physical layer (N311 is configured by the network; if the network is not configured, the default value can be used), the terminal device will declare an RLF (Re-establishment Failure). After an RLF occurs, the terminal device will attempt to restore the connection through the RRC reconstruction procedure. This may include sending an RRC Reestablishment Request message to the network device and waiting for the network device to respond to re-establish the connection. Alternatively, after an RLF occurs, the terminal device will notify the network side through failure information reporting procedures; or after the timer expires, if access stratum (AS) security is not activated, it will enter the RRC idle (RRC_IDLE) state.

[0052] Traditional RLF (Remote Link Fault) handling mechanisms typically only trigger when a serious problem occurs in the wireless link, which can lead to prolonged outages and a degraded user experience. To address this issue, the early RLF mechanism has been introduced to identify and handle potential wireless link problems at an earlier stage.

[0053] Optionally, the network device can configure or associate a timer T312 for a certain event X. If the event is reported after meeting the signal quality conditions and trigger time (Time to Trigger, TTT), the timer T312 will be started. When the timer T312 expires, it will trigger an early RLF declaration or a fast handover failure recovery process.

[0054] The timing duration of timer T312 can be any of the following: 50 milliseconds (ms), 100ms, 200ms, 300ms, 400ms, 500ms, or 1000ms. The timing duration of timer T310 can be any of the following: 50ms, 100ms, 200ms, 500ms, 1000ms, 2000ms, 4000ms, or 6000ms. Generally, the timing duration of T312 is shorter than that of T310.

[0055] As described in the background section, existing reconstruction processes can lead to increased data transmission latency; in the event of failure to obtain the context of the terminal device, the terminal device will also re-establish the RRC, resulting in data transmission interruption.

[0056] Furthermore, during conditional handover or LTM handover processes, in the event of an RLF (Recurrent Leakage Failure) or handover failure, cell selection (the selected cell is called the target cell) is required first. Handover can only proceed if the target cell is a candidate cell; otherwise, the terminal device performs an RRC (Recurrent Recall) reconstruction process within the target cell. Therefore, regardless of whether the selected cell is a candidate cell, cell selection is always necessary, resulting in some latency and data transmission interruption.

[0057] In this disclosed technical solution, the terminal device can determine whether the candidate cell meets the first handover condition before an RLF occurs, and if so, directly perform a handover to the target cell, thereby achieving early handover before the RLF occurs and reducing data transmission latency and interruption caused by drastic changes in the serving cell link. Furthermore, the terminal device can also directly perform a handover to the target cell after an RLF occurs, without the need for cell selection and RRC reconstruction procedures, further reducing data transmission latency and interruption.

[0058] To make the above-mentioned objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0059] This disclosure provides a communication method. Referring to FIG1, the following detailed steps will be described in detail.

[0060] It is understood that, in specific implementations, the communication method can be implemented using software programs, which run within a processor integrated into the chip or chip module. The method can also be implemented using a combination of software and hardware; this disclosure does not impose any limitations. The following description uses a terminal device as the executing entity.

[0061] Step 101: In response to the fact that the signal quality of at least one candidate cell meets the first handover condition before the RLF occurs, the terminal device performs a handover to the target cell, or the terminal device performs a handover to the target cell after the RLF occurs. The target cell is one of the at least one candidate cell.

[0062] In some embodiments of this disclosure, an RLF (Remote Link Failure) indicates that the terminal device has declared an RLF. Specifically, this could be due to the terminal device detecting poor wireless link quality over a period of time, after which the wireless link quality remains poor. Optionally, when the terminal device detects poor wireless link quality, it starts an RLF timer to monitor whether the wireless link can recover within the timer's duration. If the wireless link quality remains poor during the RLF timer's start time, the RLF timer expires, indicating that an RLF has occurred.

[0063] Optionally, the RLF timer may include timer T310 or timer T312.

[0064] For example, when a higher layer of the terminal device, such as the RRC layer, detects a problem, such as continuously receiving downlink out-of-sync indications from the physical layer regarding the serving cell, such as the primary cell (Pcell) or primary secondary cell (PScell), the terminal device will start timer T310. Specifically, when the terminal device receives N310 consecutive out-of-sync indications, the terminal device will consider that the radio link may be faulty, and timer T310 will be triggered. The parameter N310 is used to set the maximum number of consecutive out-of-sync indications detected by the terminal device.

[0065] For example, if timer T310 times out without receiving enough in-sync indications, such as N311, the terminal device will consider an RLF to have occurred. Here, parameter N311 is used to set the maximum number of consecutive in-sync indications detected by the terminal device.

[0066] It should be noted that the RLF timer can also be any other timer with any implementable name used for monitoring wireless link quality, and this disclosure does not impose any restrictions on it.

[0067] In some embodiments of this disclosure, the signal quality of at least one candidate cell meets a first handover condition before an RLF occurs. The first handover condition includes a required signal quality; that is, the signal quality of the candidate cell meeting the first handover condition means that the signal quality of the candidate cell meets the signal quality or entering condition required by the first handover condition.

[0068] For example, if the first handover condition includes event A4, then the signal quality of the candidate cell satisfies the first handover condition when the signal quality of the candidate cell is greater than a threshold. For example, the candidate cell's RSRP is greater than threshold 11, the candidate cell's RSRQ is greater than threshold 12, and the candidate cell's SINR is greater than threshold 13, or one or more of these conditions.

[0069] In one alternative implementation, the first handover condition includes the required signal quality and duration (e.g., a first duration). Then, the signal quality of the candidate cell satisfying the first handover condition means that the signal quality of the candidate cell meets the signal quality required by the first handover condition, and the duration of satisfaction reaches the first duration.

[0070] Optionally, the first handover condition may be configured by the network device for the terminal device or specified by the communication protocol, and this disclosure does not impose any restrictions on it.

[0071] It should be noted that the switching in this disclosure can be conditional switching, conditional LTM switching, or other processes where the terminal device judges and decides on the switching based on pre-configured switching conditions.

[0072] In one specific embodiment of this disclosure, the terminal device performs a handover to the target cell before an RLF occurs. At this time, the signal quality of the candidate cell satisfies the first handover condition, which means that the signal quality of the candidate cell meets the signal quality required by the first handover condition, and the duration of the satisfaction reaches a first duration.

[0073] Compared to existing technologies, in some embodiments of this disclosure, when the quality of the serving cell's radio link is poor, the signal quality requirements for at least one candidate cell are lower. Therefore, once a candidate cell that meets the first handover condition is found, it indicates that the current radio link quality of that cell is good, and handover can be performed immediately without waiting for the terminal device to announce an RLF, thereby reducing data transmission latency and transmission interruption.

[0074] In another specific embodiment of this disclosure, the terminal device performs a handover to the target cell after an RLF occurs. At this time, the signal quality of the candidate cell satisfying the first handover condition means that the signal quality of the candidate cell meets the signal quality required by the first handover condition, and the duration of satisfaction does not reach a first duration. It should be noted that "after an RLF occurs" can also occur before initiating an RRC reconstruction, or after timer T310, timer T312, or the RLF timer times out or expires.

[0075] Compared to the aforementioned embodiments, some embodiments of this disclosure have lower requirements for at least one candidate cell. Therefore, if at least one candidate cell meets the first handover condition before an RLF occurs, it can continue to wait until the terminal device announces the RLF, at which point the terminal device will then perform a handover to the target cell. Since some embodiments of this disclosure eliminate the need for cell selection and RRC reconstruction procedures, they can also reduce data transmission latency and interruptions.

[0076] In this disclosed technical solution, the terminal device can determine whether the candidate cell meets the first handover condition before an RLF occurs, and if so, directly perform a handover to the target cell, thereby achieving early handover before the RLF occurs and reducing data transmission latency and interruption caused by drastic changes in the serving cell link. Furthermore, the terminal device can also directly perform a handover to the target cell after an RLF occurs, without the need for cell selection and RRC reconstruction procedures, further reducing data transmission latency and interruption.

[0077] The present disclosure will now be described in detail with reference to specific embodiments.

[0078] Please refer to Figure 2, which illustrates a communication method. In some embodiments of this disclosure, the terminal device can perform cell handover in advance before an RLF occurs.

[0079] In practice, the terminal device can independently determine whether to perform conditional handover before an RLF occurs based on the first handover condition configured in the network device.

[0080] In step 201, the network device sends configuration information. Correspondingly, the terminal device receives the configuration information. The configuration information indicates a first handover condition and a second handover condition. The second handover condition is used to trigger conditional handover when there is no RLF (Recurrent Leakage Fault), while the first handover condition is used to trigger conditional handover before an RLF occurs.

[0081] In this disclosed technical solution, the terminal device can receive configuration information, which is used to indicate a first handover condition and a second handover condition. The second handover condition is used to trigger conditional handover in non-RLF scenarios. In this disclosed technical solution, the network device can configure two sets of handover parameters for the terminal device, namely the first handover condition and the second handover condition, respectively for scenarios where an RLF may occur and non-RLF scenarios. This allows the terminal device to more easily determine the target cell before an RLF occurs, smoothly achieve cell handover, and improve communication efficiency.

[0082] In some embodiments of this disclosure, the first handover condition has lower requirements for signal quality compared to the second handover condition, thereby making it easier for the terminal device to determine the target cell before an RLF occurs, so as to successfully complete the handover.

[0083] For example, the signal quality required by the first handover condition is lower than the signal quality required by the second handover condition.

[0084] For example, the duration of signal quality satisfaction required in the first switching condition is shorter than the duration of signal quality satisfaction required in the second switching condition.

[0085] In one specific implementation, the configuration information includes a second switching condition and a first switching condition.

[0086] For example, the configuration information includes a first event A3 (i.e., the first switching condition) and a second event A3 (i.e., the second switching condition), where the offset 1 in the first event A3 is lower than the offset 2 in the second event A3.

[0087] For example, the configuration information includes a first LTM event 5 (i.e., the first switching condition) and a second LTM event 5 (i.e., the second switching condition), where the absolute threshold in the first LTM event 5 is lower than the absolute threshold in the second LTM event 5.

[0088] It should be noted that the offset and absolute threshold parameters in the first and second switching conditions may include, but are not limited to, the following specific parameters: the offset of event A3 (a3-Offset), the threshold 1 of event A5 (a5-Threshold1), the threshold 2 of event A5 (a5-Threshold2), the threshold of event A4 (a4-Threshold), the hysteresis value, the trigger time (timeToTrigger), the offset of event LTM3 (LTM3-Offset), the threshold 1 of event LTM5 (LTM5-Threshold1), the threshold 2 of event LTM5 (LTM5-Threshold2), and the threshold of event LTM4 (LTM4-Threshold), etc. In another specific implementation, the configuration information includes the second switching condition and the offset between the first and second switching conditions.

[0089] For example, the configuration information includes the second event A4 (i.e., the second switching condition) and the offset between the threshold in the first event A4 (i.e., the first switching condition) and the threshold in the second event A4.

[0090] For example, the configuration information includes the second LTM event 4 (i.e., the second switching condition) and the offset between the absolute threshold in the first LTM event 4 (i.e., the first switching condition) and the absolute threshold in the second LTM event 4.

[0091] Compared to the aforementioned implementations, this disclosure only requires configuring offsets or differences based on existing configuration information, requiring less data transmission and reducing signaling overhead.

[0092] It should be noted that the specific parameters in the first and second switching conditions can be referred to the prior art, and this disclosure does not impose any restrictions on them.

[0093] Furthermore, the configuration information may also include a parameter N, which indicates the number of times the terminal device receives a step-out indication consecutively. The value of N can be less than or equal to the value of parameter N310, wherein timer T310 is started when the terminal device receives N310 consecutive step-out indications.

[0094] In practice, "non-RLF" indicates that the radio link quality of the serving cell is acceptable, for example, the RLF timer has not started and N consecutive out-of-synchronization indications have not been received. In this case, the terminal device can use the second handover condition to perform conditional handover.

[0095] In practice, the period preceding an RLF (Reversible Transfer Failure) includes one or more of the following, which are also the times when the first switching condition is used:

[0096] RLF timer starts or expires;

[0097] The system receives N consecutive out-of-step instructions, where N is a positive integer.

[0098] If the terminal device receives N consecutive out-of-synchronization instructions, the terminal device uses the first handover condition to evaluate whether to initiate an early handover, that is, to execute step 202.

[0099] Specifically, the RLF timer can be started by either timer T310 or timer T312. That is, after timer T310 or timer T312 starts, the terminal device uses the first handover condition to evaluate whether to initiate an early handover, i.e., execute step 202.

[0100] Specifically, the expiration of the RLF timer can be the expiration of timer T312. That is, when timer T312 expires, the terminal device uses the first handover condition to evaluate whether to initiate an early handover, i.e., execute step 202.

[0101] Specifically, network devices can configure timer T312 indicators in configuration information, such as conditional trigger configuration (CondTriggerConfig) or conditional LTM trigger configuration (CondLTMTriggerConfig), meaning that events in the trigger configuration are associated with timer T312. Once a candidate cell meets the first handover condition, timer T312 runs, and handover can be triggered after timer T312 expires. Alternatively, once a candidate cell meets the first handover condition, timer T312 runs, and measurement reporting is triggered, notifying the network device that the candidate cell has triggered the start of timer T312, or that the candidate cell meets the first handover condition and may trigger handover. During the execution of timer T312, the network device is monitored for subsequent scheduling or instructions; if no further scheduling or instructions are received, handover can be triggered after timer T312 expires.

[0102] It should be noted that timer T312 can also be other timers used to associate with handover conditions and trigger early handover upon expiration. This timer can be triggered by one or more candidate cells. For example, these multiple candidate cells can be a specific set of candidate cells, such as five candidate cells.

[0103] In another implementation, timer T312 is associated with a certain measurement event. If the event is met, a measurement report is triggered and timer T312 is started. If the cell that triggers the start of timer T312 is a configured candidate cell, a handover to that cell can be triggered after timer T312 expires.

[0104] For example, in a condition switching scenario, the measurement event can be one or more of events A3, A4, or A5.

[0105] For example, in a conditional LTM switching scenario, the measurement event can be one or more of LTM event 2, LTM event 3, LTM event 4, and LTM event 5.

[0106] Please refer to Figure 3 for details. Figure 3 shows the relationship between the various timers.

[0107] At time T0, the terminal device receives N consecutive out-of-synchronization (LOS) indications. At time T1, the terminal device starts timer T310. At time T2, the signal quality of the candidate cell meets the measurement event, and timer TTT starts. At time T3, timer TTT expires, and timer T312 starts. At time T4, timer T312 expires, and the terminal device prematurely declares an LRF (Local Rulfuric Failure). Correspondingly, if timer T312 has not started, at time T5, timer T310 expires, and the terminal device declares an LRF.

[0108] At any of the above times, the terminal device can evaluate whether to perform an early handover at any of the times T0, T1, T3, and T4.

[0109] In step 202, the terminal device measures one or more candidate cells to determine whether the signal quality of the one or more candidate cells meets the first handover condition before the RLF occurs. At least one candidate cell is one of the one or more candidate cells.

[0110] For example, the terminal device can evaluate the signal quality of each candidate cell at any of the times T0, T1, T3 and T4 shown in Figure 3, or it can perform the evaluation at other times.

[0111] In a specific example, in response to the start of the RLF timer, the terminal device evaluates the signal quality of one or more candidate cells.

[0112] In another specific example, in response to receiving N consecutive out-of-synchronization indications, the terminal device evaluates the signal quality of one or more candidate cells.

[0113] In step 203, in response to the fact that the signal quality of at least one candidate cell meets the first handover condition before the RLF occurs, the terminal device performs a handover to the target cell. The target cell is one of the at least one candidate cell.

[0114] In one specific example, in response to the signal quality of at least one candidate cell meeting the first handover condition and an early RLF (e.g., timer T312 expiring), the terminal device performs a handover to the target cell. Compared to the prior art that performs the RRC reconstruction procedure upon timer T310 expiring, some embodiments of this disclosure directly perform cell handover when an early handover occurs, which can trigger the handover in advance and reduce data transmission latency.

[0115] Furthermore, when there are multiple candidate cells, the target cell is the cell with the best signal quality among the candidate cells. The signal quality of the candidate cells can be represented by one or more of RSSI, RSRP, RSRQ, SNR, SINR, BER, and CSI.

[0116] For example, the target cell is the cell with the highest RSRP among at least one candidate cell.

[0117] It should be noted that the sequence numbers of the steps in some embodiments of this disclosure do not represent a limitation on the execution order of the steps.

[0118] Those skilled in the art will understand that step S203 can be considered as an execution step corresponding to step S101 in the embodiment shown in FIG1 above, and the two are complementary in their specific implementation principles and logic. Therefore, the explanation of some terms involved in the embodiments of this disclosure can be referred to the relevant description of the embodiment shown in FIG1, and will not be repeated here.

[0119] Please refer to Figure 4, which illustrates another communication method. In some embodiments of this disclosure, the terminal device can perform cell handover immediately after an RLF occurs.

[0120] In step 401, the network device sends first information. Correspondingly, the terminal device receives the first information. The first information indicates whether early handover is permitted.

[0121] In some embodiments of this disclosure, the network device configures whether to allow the terminal device to perform early handover by sending first information to the terminal device. The first information may be carried in configuration information used to configure conditional handover. Optionally, the network device sends the first information simultaneously when configuring conditional handover or LTM conditional handover for the terminal device.

[0122] In step 402, the terminal device measures one or more candidate cells and determines whether the signal quality of each candidate cell meets the first handover condition before the RLF occurs.

[0123] In practice, the terminal device can evaluate the signal quality of each candidate cell during the RLF timer operation. Specifically, the terminal device can evaluate the signal quality of each candidate cell during time T1 to time T5, or during time T3 to time T4, as shown in Figure 3.

[0124] Furthermore, if the first information indicates that early handover is permitted, the terminal device executes step 403. Conversely, if the first information indicates that early handover is not permitted, the terminal device does not execute step 403, that is, it does not perform early handover, and the terminal device performs the handover according to the normal handover procedure.

[0125] In step 403, in response to the fact that the signal quality of at least one candidate cell meets the signal quality required by the first handover condition before the RLF occurs, and the duration of meeting the signal quality required by the first handover condition does not reach a first duration, the terminal device performs a handover to the target cell after the RLF occurs. The target cell is one of the at least one candidate cell.

[0126] In the technical solution disclosed herein, the signal quality of at least one candidate cell meets the signal quality required by the first handover condition before the occurrence of RLF, and the duration of meeting the signal quality required by the first handover condition does not reach the first duration. Through the above conditions, it is easier to determine the target cell after the occurrence of RLF, smoothly realize cell handover, and improve communication efficiency.

[0127] In some embodiments of this disclosure, after an RLF occurs, the terminal device selects a target cell that met the first handover condition (i.e., the signal quality meets the signal quality required by the first handover condition, and the duration of meeting the signal quality required by the first handover condition has not reached a first duration) before the RLF occurred, and performs cell handover. Optionally, the terminal device may select the target cell and perform handover after timer T310 or timer T312 expires.

[0128] Furthermore, when there are multiple candidate cells, the target cell is the cell whose signal quality meets the requirements of the first handover condition for the longest duration. This ensures that the terminal device can hand over to a cell with relatively stable signal quality, avoiding handover failures or frequent handovers.

[0129] It should be noted that the sequence numbers of each step in the embodiments of this disclosure do not represent a limitation on the execution order of each step.

[0130] Those skilled in the art will understand that step 403 can be considered as an execution step corresponding to step 101 in the embodiment shown in FIG1, and the two are complementary in their specific implementation principles and logic. Therefore, the explanation of some terms involved in the embodiments of this disclosure can be referred to the relevant description of the embodiment shown in FIG1, and will not be repeated here.

[0131] In a non-limiting embodiment, in the above embodiments, in response to the signal quality of at least one candidate cell satisfying the first handover condition, the terminal device may report a measurement report to the network device to notify the network device of the measurement results of at least one candidate cell for the network device's reference.

[0132] Furthermore, in conditional handover or LTM handover scenarios, network devices can configure timer T312 in their configuration information. Once a candidate cell meets the first handover condition, timer T312 runs, and a measurement report is sent to the network device to notify the network device that the candidate cell has triggered the start of timer T312. During the execution of timer T312, if the terminal device does not receive other instructions from the network device, such as an instruction that the terminal device is not allowed to perform early handover, the terminal device can trigger a handover to the candidate cell after timer T312 expires.

[0133] It should be noted that timer T312 can also be any other timer with any implementable name, and this disclosure does not impose any restrictions on it.

[0134] Please refer to Figure 5, which shows a communication device 50. The communication device 50 may include:

[0135] The communication module 501 is configured to perform a handover to a target cell in response to the signal quality of at least one candidate cell satisfying a first handover condition before an RLF occurs, or to perform a handover to a target cell after an RLF occurs, wherein the target cell is a cell among at least one candidate cell.

[0136] Furthermore, the communication device 50 may also include a processing module for evaluating the signal quality of one or more candidate cells in response to the start of the RLF timer. Accordingly, the communication module 501 is also configured to perform a handover to the target cell in response to the signal quality of at least one candidate cell satisfying a first handover condition.

[0137] Furthermore, the processing module is also configured to evaluate the signal quality of one or more candidate cells in response to receiving N consecutive out-of-synchronization indications. Accordingly, the communication module 501 is also configured to perform a handover to the target cell in response to the signal quality of at least one candidate cell meeting a first handover condition.

[0138] Furthermore, the processing module is also configured to start an RLF timer in response to the signal quality of at least one candidate cell meeting the first handover condition. Accordingly, the communication module 501 is also configured to perform a handover to the target cell in response to the expiration of the RLF timer, whereby the expiration of the RLF timer indicates an early RLF.

[0139] Furthermore, the communication module 501 is also used to report a measurement report in response to the signal quality of at least one candidate cell meeting the first handover condition.

[0140] Furthermore, in response to the occurrence of RLF, the communication module 501 selects a target cell and performs a handover to the target cell. The signal quality of at least one candidate cell meets the signal quality required by the first handover condition before the occurrence of RLF, and the duration of meeting the signal quality required by the first handover condition does not reach the first duration.

[0141] Furthermore, the communication module 501 is also used to receive first information, which indicates whether early switching is permitted.

[0142] Furthermore, the communication module 501 is also used to receive configuration information, which is used to indicate a first switching condition and a second switching condition, and the second switching condition is used to trigger condition switching when there is no RLF.

[0143] In specific implementations, the aforementioned communication device 50 may correspond to a chip with communication function in a terminal device, such as a system-on-a-chip (SOC), a baseband chip, etc.; or to a chip module in a terminal device that includes a chip with communication function; or to a chip module with a chip with data processing function; or to a terminal device.

[0144] In another non-limiting embodiment, the communication module 501 is used to perform a handover of the terminal device to a target cell before or after an RLF occurs, the target cell being a cell among at least one candidate cell, the signal quality of the at least one candidate cell satisfying a first handover condition before the RLF occurs.

[0145] Furthermore, the communication module 501 is also used to send configuration information, which is used to indicate the first switching condition and the second switching condition, and the second switching condition is used to trigger the condition switching when there is no RLF.

[0146] Furthermore, the communication module 501 is also used to send first information, which indicates whether early switching is allowed.

[0147] In specific implementations, the aforementioned communication device 50 may correspond to a chip with communication function in a network device, such as a SOC or baseband chip; or to a chip module in a network device that includes a chip with communication function; or to a chip module with a chip that has data processing function; or to a network device.

[0148] Other relevant descriptions of the communication device 50 can be found in the descriptions in the foregoing embodiments, and will not be repeated here.

[0149] Regarding the modules / units included in the various devices and products described in the above embodiments, they can be software modules / units, hardware modules / units, or a combination of both. For example, for devices and products applied to or integrated into a chip, all modules / units can be implemented using hardware methods such as circuits, or at least some modules / units can be implemented using software programs running on a processor integrated within the chip, while the remaining (if any) modules / units can be implemented using hardware methods such as circuits. For devices and products applied to or integrated into a chip module, all modules / units can be implemented using hardware methods such as circuits. Different modules / units can be located in the same component (e.g., chip, circuit module, etc.) or different components of the chip module, or at least some modules / units can be implemented using hardware methods such as circuits. The implementation is achieved through a software program that runs on a processor integrated within the chip module. The remaining modules / units (if any) can be implemented using hardware methods such as circuits. For various devices and products applied to or integrated into terminal equipment, each of their modules / units can be implemented using hardware methods such as circuits. Different modules / units can be located in the same component (e.g., chip, circuit module, etc.) or different components within the terminal equipment. Alternatively, at least some modules / units can be implemented using a software program that runs on a processor integrated within the terminal equipment, while the remaining modules / units (if any) can be implemented using hardware methods such as circuits.

[0150] This disclosure also discloses a storage medium, which is a computer-readable storage medium storing a computer program thereon. When the computer program is executed, it can perform the steps of the method shown in the foregoing embodiments. The storage medium may include read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk, etc. The storage medium may also include non-volatile memory or non-transitory memory, etc.

[0151] Referring to Figure 6, this disclosure also provides a hardware structure diagram of a communication device. The device includes a processor 601, a memory 602, and a transceiver 603.

[0152] Processor 601 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of programs according to the present disclosure. Processor 601 may also include multiple CPUs, and processor 601 may be a single-core processor or a multi-core processor. Here, "processor" may refer to one or more devices, circuits, or processing cores for processing data (e.g., computer program instructions).

[0153] The memory 602 may be a ROM or other type of static storage device capable of storing static information and instructions, RAM or other type of dynamic storage device capable of storing information and instructions, or it may be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer. This disclosure does not impose any limitations on this. The memory 602 may exist independently (in which case, the memory 602 may be located outside or inside the device) or it may be integrated with the processor 601. The memory 602 may contain computer program code. The processor 601 is used to execute the computer program code stored in the memory 602 to implement the method provided in this disclosure.

[0154] The processor 601, memory 602, and transceiver 603 are connected via a bus. The transceiver 603 is used to communicate with other devices or communication networks. Optionally, the transceiver 603 may include a transmitter and a receiver. The device in the transceiver 603 that implements the receiving function can be considered as a receiver, which is used to perform the receiving steps in the embodiments of this disclosure. The device in the transceiver 603 that implements the transmitting function can be considered as a transmitter, which is used to perform the transmitting steps in the embodiments of this disclosure.

[0155] When the structural diagram shown in Figure 6 is used to illustrate the structure of the terminal device involved in the above embodiments, the processor 601 is used to control and manage the actions of the terminal device. For example, the processor 601 is used to support the terminal device in performing actions performed by the terminal device in other processes described in the embodiments of this disclosure. The processor 601 can communicate with other network entities through the transceiver 603, for example, with the aforementioned network device. The memory 602 is used to store the program code and data of the terminal device.

[0156] When the structural diagram shown in Figure 6 is used to illustrate the structure of the network device involved in the above embodiments, the processor 601 is used to control and manage the actions of the network device. For example, the processor 601 is used to support the network device in performing actions performed by the network device in other processes described in the embodiments of this disclosure. The processor 601 can communicate with other network entities through the transceiver 603, for example, with the aforementioned terminal device. The memory 602 is used to store the program code and data of the network device.

[0157] All embodiments of this disclosure can be executed individually or in combination with other embodiments, and are all considered to be within the scope of protection claimed by this disclosure.

[0158] In this embodiment of the disclosure, a one-way communication link from the access network to the terminal device is defined as a downlink, and the data transmitted on the downlink is called downlink data. The transmission direction of the downlink data is called the downlink direction. On the other hand, a one-way communication link from the terminal device to the access network is defined as an uplink, and the data transmitted on the uplink is called uplink data. The transmission direction of the uplink data is called the uplink direction.

[0159] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article indicates that the preceding and following related objects have an "or" relationship.

[0160] In this disclosure, "multiple" refers to two or more.

[0161] The descriptions of "first," "second," etc., appearing in the embodiments of this disclosure are for illustrative purposes and to distinguish the objects being described. They have no order and do not indicate any particular limitation on the number of devices in the embodiments of this disclosure, nor do they constitute any limitation on the embodiments of this disclosure.

[0162] The term "connection" in this disclosure refers to various connection methods, such as direct connection or indirect connection, to achieve communication between devices. This disclosure does not limit the scope of the term.

[0163] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, all or part of the processes or functions described in the embodiments of this disclosure are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means.

[0164] It should be understood that in the various embodiments of this disclosure, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this disclosure.

[0165] In the several embodiments provided in this disclosure, it should be understood that the disclosed methods, apparatuses, and systems can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for example, the division of units is merely a logical functional division, and other division methods may exist in actual implementation; for example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0166] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the objectives of some embodiments of this disclosure, depending on actual needs.

[0167] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can be physically comprised separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in the form of hardware plus software functional units.

[0168] The integrated unit implemented as a software functional unit described above can be stored in a computer-readable storage medium. This software functional unit, stored in a storage medium, includes several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute some steps of the methods described in the various embodiments of this disclosure.

[0169] While the above disclosure is provided, it is not limited thereto. Any person skilled in the art may make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure shall be determined by the scope defined in the claims.

Claims

1. A communication method, comprising: In response to the signal quality of at least one candidate cell satisfying a first handover condition before a radio link failure (RLF) occurs, a handover to a target cell is performed, or a handover to the target cell is performed after an RLF occurs, wherein the target cell is a cell among the at least one candidate cell.

2. The communication method according to claim 1, wherein, The occurrence of RLF includes one or more of the following: The RLF timer starts or expires, and the expiration of the RLF timer indicates that an RLF has occurred. The system receives N consecutive out-of-step instructions, where N is a positive integer.

3. The communication method according to claim 2, wherein the RLF timer includes timer T310 or timer T312.

4. The communication method according to claim 2 or 3, wherein, The step of performing a handover to the target cell in response to the signal quality of at least one candidate cell satisfying a first handover condition before an RLF occurs includes: In response to the start of the RLF timer, the signal quality of one or more candidate cells is evaluated, wherein the at least one candidate cell is a cell among the one or more candidate cells; In response to the signal quality of the at least one candidate cell satisfying the first handover condition, a handover to the target cell is performed.

5. The communication method according to claim 1 or 2, wherein, The step of performing a handover to the target cell in response to the signal quality of at least one candidate cell satisfying a first handover condition before an RLF occurs includes: In response to receiving N consecutive out-of-synchronization indications, the signal quality of one or more candidate cells is evaluated, wherein the at least one candidate cell is a cell among the one or more candidate cells, and N is a positive integer; In response to the signal quality of the at least one candidate cell satisfying the first handover condition, a handover to the target cell is performed.

6. The communication method according to any one of claims 1 to 3, wherein The step of performing a handover to the target cell in response to the signal quality of at least one candidate cell satisfying a first handover condition before an RLF occurs includes: In response to the signal quality of the at least one candidate cell satisfying the first handover condition, the RLF timer is started; In response to the expiration of the RLF timer, a handover to the target cell is performed, whereby the expiration of the RLF timer indicates an early RLF.

7. The communication method according to claim 6 further includes: In response to the signal quality of the at least one candidate cell satisfying the first handover condition, a measurement report is reported.

8. The communication method according to claim 1, wherein The step of performing a handover to the target cell after an RLF occurs includes: In response to an RLF, a target cell is selected and a handover is performed to the target cell, wherein the signal quality of the at least one candidate cell meets the signal quality required by the first handover condition before the RLF occurs, and the duration for which the signal quality required by the first handover condition is met does not reach a first duration.

9. The communication method according to claim 1 or 8, further comprising: Receive first information, which indicates whether early switching is permitted.

10. The communication method according to any one of claims 1 to 7, further comprising: Receive configuration information, which is used to indicate the first switching condition and the second switching condition, and the second switching condition is used to trigger condition switching when there is no RLF.

11. The communication method according to claim 10, wherein The configuration information includes the second switching condition and the first switching condition; Alternatively, the configuration information may include the second switching condition and the offset between the first switching condition and the second switching condition.

12. The communication method according to any one of claims 1 to 11, wherein, The target cell is the cell with the best signal quality among the at least one candidate cell, or the cell whose signal quality meets the requirements of the first handover condition for the longest duration.

13. A communication method, comprising: Before or after an RLF occurs, the terminal device performs a handover to a target cell, which is a cell among at least one candidate cell, and the signal quality of the at least one candidate cell meets a first handover condition before the RLF occurs.

14. The communication method according to claim 13, comprising: Send configuration information, which is used to indicate the first switching condition and the second switching condition, and the second switching condition is used to trigger condition switching when there is no RLF.

15. The communication method according to claim 14, wherein, The configuration information includes the second switching condition and the first switching condition; Alternatively, the configuration information may include the second switching condition and the offset between the first switching condition and the second switching condition.

16. A communication device, comprising: A communication module is configured to perform a handover to a target cell in response to a first handover condition being met before an RLF occurs in at least one candidate cell, or to perform a handover to the target cell after an RLF occurs, wherein the target cell is a cell among the at least one candidate cell.

17. A communication device, comprising: A communication module is used to perform a handover of a terminal device to a target cell before or after an RLF occurs, wherein the target cell is a cell among at least one candidate cell, and the signal quality of the at least one candidate cell meets a first handover condition before the RLF occurs.

18. A computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to perform the steps of the communication method of any one of claims 1 to 12, or to perform the steps of the communication method of any one of claims 13 to 15.

19. A computer program product comprising a computer program / instructions that, when executed by a processor, implement the steps of the communication method of any one of claims 1 to 12, or perform the steps of the communication method of any one of claims 13 to 15.

20. A communication device comprising a memory and a processor, the memory storing a computer program executable on the processor, the processor executing the steps of the communication method according to any one of claims 1 to 12 when running the computer program.

21. A communication device comprising a memory and a processor, the memory storing a computer program executable on the processor, the processor executing the steps of the communication method of any one of claims 13 to 15 when running the computer program.

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