CN112243248A

CN112243248A - Link state monitoring method and terminal of direct link

Info

Publication number: CN112243248A
Application number: CN201910651612.XA
Authority: CN
Inventors: 王达; 赵锐; 赵亚利
Original assignee: Datang Mobile Communications Equipment Co Ltd
Current assignee: Datang Mobile Communications Equipment Co Ltd
Priority date: 2019-07-18
Filing date: 2019-07-18
Publication date: 2021-01-19
Also published as: WO2021008227A1

Abstract

The application provides a link state monitoring method and a terminal of a direct link, and belongs to the technical field of wireless communication. The method comprises the steps that a first terminal sets a timer when monitoring the link state of a straight-through link, the timer corresponding to the straight-through link is started according to the starting condition of the timer after the link state of the straight-through link between the first terminal and a second terminal is determined, and the link state of the straight-through link is determined to be unchanged during the running period of the timer. Through the mode, even if no periodic RLM signal is available for measurement on the through link, the first terminal can determine the link state of the through link according to the link state of the through link determined when the timer is started during the running period of the timer, and further monitoring of the link state of the through link is achieved.

Description

Link state monitoring method and terminal of direct link

Technical Field

The present application relates to the field of wireless communication technologies, and in particular, to a link state monitoring method and a terminal for a direct link.

Background

Terminals that are close to each other and terminals that are close to each other allow direct communication between the terminals. As shown in fig. 1, for convenience of description, a direct communication link between a terminal and a terminal is defined as a through link. The wireless interface on the terminal corresponding to the direct link is called a direct communication interface, also called a SL (direct communication) interface. The communication link between the network and the terminal is called a Uu link (cellular communication link), and the radio interface on the terminal corresponding to the cellular communication link is called a Uu interface.

In an LTE (Long Term Evolution ) system, services of a direct communication interface only support broadcast services, and for an NR (New Radio, New air interface) system, services of the direct communication interface are richer than those of the LTE system, and besides the broadcast services, unicast services and multicast services are also supported. For the broadcast service and the multicast service, link connection does not need to be established, and management and maintenance of the link are also not needed, so that a direct communication interface in the LTE system does not need to carry out link management. However, for the unicast service, that is, when two UEs (User equipments) perform direct communication, link connection needs to be established and management and maintenance needs to be performed on the link.

Generally, the Link status can be determined by measuring an RLM (Radio Link Monitoring) signal. In the unicast service scenario of two terminals of the NR system, the RLM signal on the through link is transmitted along with the through link data, and if the through link data is aperiodic, no periodic RLM signal on the through link is available for measurement, so that link status monitoring cannot be performed.

Disclosure of Invention

The application provides a link state monitoring method and a terminal of a direct link, which are used for solving the problem that the direct link state monitoring can not be carried out in the prior art.

In a first aspect, an embodiment of the present application provides a method for monitoring a link state of a direct link, where the method includes:

the method comprises the steps that a first terminal determines the link state of a direct link between the first terminal and a second terminal, and starts a timer corresponding to the direct link according to a timer starting condition;

the first terminal determines that the link state of the through link is unchanged during the running of the timer.

According to the method for monitoring the link state of the through link, the first terminal is provided with the timer, after the link state of the through link between the first terminal and the second terminal is determined, the timer corresponding to the through link is started according to the starting condition of the timer, and the link state of the through link is determined to be unchanged during the running period of the timer. Through the mode, even if no periodic RLM signal is available for measurement on the through link, the first terminal can determine the link state of the through link according to the link state of the through link determined when the timer is started during the running period of the timer, and further monitoring of the link state of the through link is achieved.

In a possible implementation manner, the starting, by the first terminal, the timer according to a timer starting condition includes:

when a timer starting condition is met, if a timer corresponding to the running straight-through link does not exist currently, the first terminal starts the timer corresponding to the straight-through link; or

When a timer starting condition is met, if a timer corresponding to the straight-through link which is running currently exists, the first terminal stops the running timer and starts a new timer corresponding to the straight-through link.

In the method, for any straight-through link, if a new timer starting condition is met before the running of the timer is finished, the currently running timer is stopped and a new timer is started, and during the running period of the new timer, the link state of the straight-through link is periodically determined to be unchanged according to the link state of the straight-through link determined when the new timer is started, so that the link state of the straight-through link is continuously monitored.

In a possible implementation manner, the timer starting condition is that the physical layer of the first terminal receives the RLM signal of the direct link or the access layer of the first terminal receives the link state of the direct link reported by the physical layer of the first terminal.

In the method, the timer can be started by a physical layer or an access layer of the first terminal, and flexible control can be realized. If the physical layer of the first terminal starts the timer, the received RLM signal of the through link is used as a trigger condition for starting the timer, when the physical layer of the first terminal receives the RLM signal of the through link, the physical layer confirms that the timer starting condition is met, the timer is started, and the link state of the through link is periodically determined to be unchanged during the running period of the timer. If the access layer of the first terminal starts the timer, the received link state of the through link reported by the physical layer is used as a trigger condition for starting the timer, when the access layer of the first terminal receives the link state of the through link reported by the physical layer, the fact that the timer starting condition is met is confirmed, the timer is started, and the link state of the through link is periodically determined to be unchanged during the running period of the timer.

In one possible implementation, the timer starting condition is that a physical layer of the first terminal receives an RLM signal of the direct link, and the determining, by the first terminal, a link state of the direct link with a second terminal includes:

and the physical layer of the first terminal determines the link state of the through link according to the received RLM signal.

In the above method, the step of determining the link status of the direct link is performed by a physical layer of the first terminal, and the physical layer of the first terminal may determine the link status of the direct link according to the received RLM signal. The method for determining the link state of the downlink by the Uu interface is applied to the SL interface for determining the link state of the direct link, so that the link state of the direct link can be accurately determined.

In one possible implementation, the method further includes:

and if the running of the timer corresponding to the through link is finished and no new timer corresponding to the through link is started, the physical layer determines that the link state of the through link is an uncertain state.

In the method, if the timer corresponding to the through link ends and no new RLM signal is received, the physical layer of the first terminal cannot determine the current link state of the through link according to the RLM signal, and at this time, the link state of the through link is considered to be an uncertain state, the new timer may not be started, and when the RLM signal is received again, the new timer is started again, and the link state of the through link is continuously monitored. If a new RLM signal is not received until the first terminal determines that the straight-through link fails to be connected, subsequent operations can be performed according to a processing mode when the link fails to be connected, and the monitoring process of the link state of the straight-through link is completed.

In one possible implementation, the method further includes:

and the physical layer reports the determined link state of the straight-through link to an access layer of the first terminal according to a set link state reporting period.

In the method, the physical layer of the first terminal reports the determined link state of the through link to the access layer of the first terminal according to the set link state reporting period, so that the access layer of the first terminal monitors whether the through link fails to be connected according to the link state reported by the physical layer, and the monitoring and subsequent processing of the link state of the through link are realized.

In a possible implementation manner, the enabling condition of the timer is that an access layer of the first terminal receives a link state of a direct link reported by a physical layer of the first terminal, and determining, by the first terminal, the link state of the direct link with a second terminal includes:

and the access layer of the first terminal takes the link state reported by the physical layer of the first terminal as the link state of the straight-through link.

In the method, the access layer of the first terminal executes the step of determining the link state of the through link, and when the condition of starting the timer is met, the access layer of the first terminal can take the link state reported by the physical layer as the link state of the through link, so that the method is simple and easy to implement.

In one possible implementation, the method further includes:

if the running of the timer is finished and no new timer corresponding to the straight-through link is started, the access layer determines that the link state of the straight-through link is an uncertain state;

and when the continuous times that the link state of the straight-through link is in the uncertain state reach a set number, the access layer determines that the straight-through link fails to be connected.

In the method, if the timer corresponding to the through link ends and a new link state reported by the physical layer is not received, the access layer of the first terminal cannot determine the current link state of the through link according to the link state reported by the physical layer, and at this time, the link state of the through link is considered to be an uncertain state, so that the new timer is not started, and when the link state reported by the physical layer is received again, the new timer is started again, and the link state of the through link is continuously monitored. And if the continuous times that the link state of the straight-through link is in the uncertain state reach the set number, the access layer of the first terminal determines that the straight-through link fails to be connected, and performs subsequent operation according to the processing mode when the link fails to be connected, so as to complete the monitoring process of the link state of the straight-through link.

In a possible implementation manner, the first terminal determines the duration of the timer corresponding to the direct link by:

and the first terminal determines the time length of the timer corresponding to the through link according to the corresponding relation between the configured or preconfigured state parameter of the through link and the time length of the timer.

In the above method, the correspondence between the state parameter of the direct link and the duration of the timer may be configured by the network device, or may be preconfigured in the first terminal when the first terminal leaves the factory. And starting timers with different durations according to different state parameters of the through link, and shortening the duration of the timer when the state of the through link is unstable so as to reflect the link state of the through link in time.

In one possible implementation, the state parameter of the direct link includes one or a combination of the following parameters:

the link state of the through link, the channel quality of the through link, the type of the synchronization source, the accuracy of the synchronization source, the speed of the first terminal in the through link, the speed of the second terminal in the through link, the relative speed between the first terminal and the second terminal in the through link, and the distance between the first terminal and the second terminal in the through link.

In a second aspect, an embodiment of the present application provides a terminal, including: a processor and a memory;

the processor is used for reading the instructions in the memory and executing the following steps:

determining the link state of a direct link between the first terminal and the second terminal, and starting a timer corresponding to the direct link according to a timer starting condition;

determining that a link state of the through link is unchanged during the timer running.

In one possible implementation, the processor specifically performs:

In a possible implementation manner, the timer starting condition is that a physical layer of the first terminal receives an RLM signal of the direct link, and the processor specifically performs:

determining, by the physical layer, a link state of the through link from the received RLM signal.

In one possible implementation, the processor further performs:

and if the running of the timer corresponding to the through link is finished and no new timer corresponding to the through link is started, determining that the link state of the through link is an uncertain state through the physical layer.

In one possible implementation, the processor further performs:

and reporting the determined link state of the straight-through link to an access layer of the first terminal through the physical layer according to a set link state reporting period.

In a possible implementation manner, the timer is started on condition that the access layer of the first terminal receives a link state of the direct link reported by the physical layer of the first terminal, and the processor specifically executes:

and taking the link state reported by the physical layer of the first terminal as the link state of the straight-through link through the access layer.

In one possible implementation, the processor further performs:

if the running of the timer is finished and no new timer corresponding to the straight-through link is started, determining that the link state of the straight-through link is an uncertain state through the access layer;

and when the continuous times that the link state of the straight-through link is the uncertain state reach a set number, determining that the straight-through link fails to be connected through the access layer.

In one possible implementation, the processor further performs:

and determining the time length of the timer corresponding to the through link according to the corresponding relation between the configured or preconfigured state parameter of the through link and the time length of the timer.

In a third aspect, an embodiment of the present application provides a terminal, including:

the timer starting unit is used for determining the link state of the direct link between the second terminal and the timer starting unit and starting the timer corresponding to the direct link according to the timer starting condition;

a link state determination unit, configured to determine that a link state of the through link is unchanged during operation of the timer.

In a possible implementation manner, the timer starting unit is further configured to:

In a possible implementation manner, the timer starting condition is that a physical layer of the first terminal receives an RLM signal of the direct link, and the timer starting unit is further configured to:

In a possible implementation manner, the link state determination unit is further configured to:

In a possible implementation manner, the timer starting condition is that the access layer of the first terminal receives a link state of the direct link reported by the physical layer of the first terminal, and the timer starting unit is further configured to:

In a fourth aspect, the present application provides a computer-readable storage medium, where a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method for monitoring a link state of a direct link in any one of the above first aspects are implemented.

In addition, for technical effects brought by any one implementation manner of the second aspect to the fourth aspect, reference may be made to technical effects brought by different implementation manners of the first aspect, and details are not described here.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic view of an application architecture of a method for monitoring a link state of a direct link according to an embodiment of the present application;

fig. 2 is an interaction diagram for establishing a direct link between two terminals according to an embodiment of the present application;

fig. 3 is a flowchart of a method for monitoring a link state of a direct link according to an embodiment of the present application;

fig. 4 is a flowchart of another link status monitoring method for a direct link according to an embodiment of the present application;

fig. 5 is a schematic process diagram of a physical layer monitoring a link state of a direct link according to an embodiment of the present application;

fig. 6 is a schematic diagram illustrating a determination of a connection failure of a direct link according to an embodiment of the present application;

fig. 7 is a schematic diagram of another process for monitoring a link status of a direct link by a physical layer according to an embodiment of the present application;

fig. 8 is a flowchart of another link status monitoring method for a direct link according to an embodiment of the present application;

fig. 9 is a schematic process diagram of an access stratum monitoring a link state of a direct link according to an embodiment of the present application;

fig. 10 is a schematic diagram of another process of monitoring a link state of a direct link by an access layer according to an embodiment of the present application;

fig. 11 is a block diagram of a terminal according to an embodiment of the present disclosure;

fig. 12 is a block diagram of another terminal according to an embodiment of the present disclosure.

Detailed Description

Hereinafter, some terms in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.

(1) A terminal: a device with wireless communication function can be deployed on land, including indoors or outdoors, hand-held or vehicle-mounted; can also be deployed on the water surface (such as a ship and the like); and may also be deployed in the air (e.g., airplanes, balloons, satellites, etc.). The terminal may be a mobile phone (mobile phone), a tablet computer (pad), a computer with wireless transceiving function, a VR (virtual reality) terminal, an AR (augmented reality) terminal, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote medical treatment (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), etc.; but also UEs of various forms, Mobile Stations (MSs), terminal equipments (terminal devices), etc.

(2) A network device: an apparatus for providing wireless communication functions for a terminal, comprising but not limited to: a gbb, an RNC (radio network controller), an NB (node B), an eNB, a BSC (base station controller), a BTS (base transceiver station), an HNB (e.g., home evolved node B or home node B), a BBU (base band Unit), a TRP (transmission and reception point), a TP (transmission point), a mobile switching center, and the like in 5G.

(3) An uncertain state: when the link state of the through link cannot be determined to be the IS state or the OOS state according to the RLM signal, the link state of the through link IS determined to be a third state different from the IS state and the OOS state.

(4) In the embodiments of the present application, the term "plurality" means two or more, and other terms are similar thereto.

The network architecture and the service scenario described in the embodiment of the present application are for more clearly illustrating the technical solution of the embodiment of the present application, and do not form a limitation on the technical solution provided in the embodiment of the present application, and as a person of ordinary skill in the art knows that along with the evolution of the network architecture and the appearance of a new service scenario, the technical solution provided in the embodiment of the present application is also applicable to similar technical problems.

Fig. 1 shows an application architecture diagram of a link state monitoring method for a direct link according to an embodiment of the present application, that is, a communication diagram of a V2X (Vehicle to Everything) system. In fig. 1, UE1 and UE2 are terminals, and eNodeB (i.e., eNB base station) is a network device. Two terminals UE1 and UE2 are connected to the core network through a network device eNodeB. In the NR system, direct communication is supported between terminals close to each other. Direct communication may be possible between UE1 and UE2 as in fig. 1. The terminals of the direct communication can be all on-line or all off-line, or part of the terminals can be on-line or off-line. The terminal participating in direct communication, i.e. on-line, is located within the coverage of the communication carrier of the base station, and the terminal participating in direct communication, i.e. off-line, is not located within the coverage of the communication carrier of the base station.

The direct communication link between the two terminals UE1 and UE2 in fig. 1 is a direct link (e.g., Sidelink, SL in fig. 1), and the wireless interfaces on UE1 and UE2 corresponding to the direct link may be both referred to as SL interfaces. The communication link between terminal UE1 and network device eNodeB is referred to as a uulink, and the communication link between terminal UE2 and network device eNodeB is also referred to as a uulink. The radio interfaces on both UE1 and UE2 corresponding to the uulink may be referred to as the Uu interface.

In the NR system, typical communication scenarios for direct communication include the following three types:

one-to-one communication (unicast) between direct communication terminals;

a device can send the same data to all devices in a communication group at a time (multicast);

one device can send the same data (broadcast) to all nearby devices at once.

In the conventional LTE system, the service of the SL interface supports only the broadcast service. For the NR system, however, as described above, the SL interface supports both unicast traffic and multicast traffic in addition to broadcast traffic. For broadcast service and multicast service, no link connection is required to be established, and no link management and maintenance are required. However, for unicast traffic, i.e., direct communication between UE1 and UE2, a link connection needs to be established and the link needs to be managed and maintained. Generally, the link can be managed and maintained by determining the link state by measuring the RLM signal.

For the link between the terminal and the network device, the RLM signal transmitted on the link between the terminal and the network device is periodic. For a direct link between two terminals, RLM signals on the link are sent along with direct link data, if the direct link data are non-periodic, no periodic RLM signals are available for measurement on the direct link, but link management requires periodic determination of link status, and therefore link status monitoring cannot be performed on the direct link.

Based on this, embodiments of the present application provide a link state monitoring method and a terminal for a direct link, which may periodically determine a link state based on a measurement of an aperiodic RLM signal, so as to monitor the link state of the direct link.

In a unicast service scenario of the SL interface of the NR system, a direct link unicast connection between two terminals is supported, for example, RRC (Radio Resource Control) connection, SL RRC (Sidelink Radio Resource Control, direct link Radio Resource Control signaling) connection, NAS (Non Access Stratum) connection, or the like. The process of establishing a direct link unicast connection between two terminals may be implemented by an AS (Access Stratum), or may be implemented by an NAS. For an example, a process of establishing a direct link connection between two terminals can be seen in fig. 2.

In establishing the direct link unicast connection, various information may be transmitted between the UE1 and the UE2 through a network device (e.g., an eNB base station). Or the network device allocates resources, including channel resources, required for establishing the direct link unicast connection, to the UE1 and the UE2, and each piece of information is transmitted between the UE1 and the UE2 through the direct link. In the manner described above, the UE1 may establish direct link connections with multiple terminals, including the UE 2.

After the UE1 and the UE2 establish the direct link unicast connection, data can be directly transmitted through the direct link between the UE1 and the UE2 without being forwarded through the network device. During the existence of the direct link unicast connection between the UE1 and the UE2, both the UE1 and the UE2 need to maintain and manage the direct link, including monitoring the link status of the direct link, and storing communication context (e.g., peer UE capabilities), etc. Both the UE1 and the UE2 may monitor the link state of the direct link between the UE1 and the UE2 by using the link state monitoring method for the direct link provided in the embodiments of the present application.

The following describes an implementation procedure of the method for monitoring the link state of the direct link, which is provided by the embodiment of the present application, with a first terminal as an implementation subject. In the following description, the first terminal and the second terminal refer to two terminals that perform direct communication. When the first terminal performs direct communication with the second terminal, the first terminal may also perform direct communication with another terminal such as a third terminal at the same time. The first terminal will be described with reference to UE1 and the second terminal will be described with reference to UE 2. Note that the first terminal is not exactly equal to UE1, nor is the second terminal exactly equal to UE 2.

When the first terminal and the second terminal are In the direct link connection state, the physical layer Of the first terminal may determine a link state Of the direct link, such as an IS (In-Sync) state and an OOS (Out-Of-Sync) state, according to an RLM signal Of the direct link between the first terminal and the second terminal, and periodically report the link state Of the direct link to an access layer Of the first terminal. And the access layer determines whether the through link fails to be connected according to the received link state of the through link. And if the access layer determines that the direct Link fails to be connected, determining that a Radio Link Failure (RLF) exists. For example, the Access Stratum may issue a RLF declaration to a NAS (Non Access Stratum) to cause the NAS layer to restart the direct communication setup procedure or not.

Since the RLM signal on the through link between the two terminals may be aperiodic, the physical layer of the first terminal cannot determine the link status of the through link from the periodic RLM signal. In order to solve the above problem, in the embodiments of the present application, a timer is provided, the timer is started after determining the link state of the through link, and the link state is determined to be unchanged during the running of the timer, so that the link state of the through link can be monitored based on the aperiodic RLM signal.

Fig. 3 shows a flowchart of a method for monitoring a link state of a direct link, where the embodiment is described by taking an example that a first terminal monitors a link state of a direct link between a first terminal and a second terminal as an example, and therefore, a direct link mentioned in this embodiment refers to a direct link between a first terminal and a second terminal. The second terminal may monitor the link status of the direct link between the first terminal and the second terminal in the same way.

When the first terminal performs direct communication with the second terminal, the first terminal may perform direct communication with another terminal such as a third terminal at the same time. The first terminal may monitor the link status of the direct link between the first terminal and the third terminal in the same way. The third terminal may also monitor the link status of the direct link between the first terminal and the third terminal in the same way.

As shown in fig. 3, the method comprises the steps of:

step S301, the first terminal determines the link state of the direct link between the first terminal and the second terminal, and starts a timer corresponding to the direct link according to a timer starting condition.

When a Timer starting condition is met, if a Timer (Timer) corresponding to the running straight-through link does not exist currently, the first terminal starts the Timer corresponding to the straight-through link; and if the timer corresponding to the running straight-through link exists currently, the first terminal stops the running timer and starts a new timer corresponding to the straight-through link.

Step S302, the first terminal determines that the link status of the direct link is unchanged during the running of the timer.

The method for monitoring the link state of the through link comprises the steps that a timer is arranged, the first terminal determines the link state of the through link between the first terminal and the second terminal, the timer corresponding to the through link is started according to the starting condition of the timer, and the link state of the through link is determined to be unchanged during the running period of the timer, so that the link state of the through link can be monitored based on a non-periodic RLM signal, and whether the through link fails to be connected or not is determined. When the direct link connection fails, the RLF declaration is issued in time. And if a new timer starting condition is met before the running of the timer is finished, stopping the currently running timer and starting the new timer, and periodically determining that the link state of the through link is unchanged according to the link state of the through link determined when the new timer is started during the running of the new timer so as to continuously monitor the link state of the through link.

Before starting the timer, the first terminal determines the duration of the timer and starts the timer according to the determined duration of the timer.

Alternatively, the duration of the timer may be configured and sent to the first terminal by the network device, preconfigured in the first terminal when the first terminal leaves the factory, or specified by the communication protocol. The duration of the timer may be a fixed value or a set duration range. The first terminal may select a value in the set duration range as the duration of the timer according to actual needs.

Optionally, the first terminal may further determine, according to a correspondence between a configured or preconfigured status parameter of the direct link and a time length of the timer, a time length of the timer corresponding to the direct link. The state parameters of the through link comprise one or a combination of the following parameters: the link state of the through link, the channel quality of the through link, the type of the synchronization source, the accuracy of the synchronization source, the speed of the first terminal in the through link, the speed of the second terminal in the through link, the relative speed between the first terminal and the second terminal in the through link, and the distance between the first terminal and the second terminal in the through link.

And starting timers with different durations according to different state parameters of the through link, and shortening the duration of the timer when the state of the through link is unstable so as to reflect the link state of the through link in time.

For example, in some embodiments, the correspondence between the link status of the through link and the duration of the timer, as specified by the network device configuration or communication protocol, may be preconfigured. For example, the link states of a through link include an IS state and an OOS state. The timer duration corresponding to the IS state IS T1, and the timer duration corresponding to the OOS state IS T2. Since the state of the through link is unstable when it is in the OOS state, T1 may be greater than or equal to T2. For another example, the timer duration corresponding to the IS state IS a duration Range1 (from T3 to T4, where T4 IS greater than or equal to T3), and the timer duration corresponding to the OOS state IS a duration Range2 (from T5 to T6, where T6 IS greater than or equal to T5), where the value of Range2 may be greater than or equal to the value of Range1, or the values of Range1 and Range2 may overlap. The first terminal may arbitrarily select a value in the duration range of the corresponding timer according to the determined link status of the direct link, as the duration of the timer.

In other embodiments, the correspondence between the channel quality of the pass-through link and the duration of the timer may be preconfigured, specified by the network device configuration or the communication protocol. Different through link channel qualities correspond to different timer durations or timer duration ranges. Optionally, the worse the channel quality of the direct link is, the shorter the duration of the timer is; the better the channel quality of the through link, the longer the duration of the timer. Since the worse the channel quality of the through link, the more likely the channel conditions will change. For example, as shown in table 1, when the channel quality Q of the through link is greater than or equal to Q1 and less than Q2, the duration of the corresponding timer is T1 or Range1, when the channel quality Q of the through link is greater than or equal to Q2 and less than Q3, the duration of the corresponding timer is T2 or Range2, when the channel quality Q of the through link is greater than or equal to Q3 and less than or equal to Q4, the duration of the corresponding timer is T3 or Range 3. Wherein T1 is not less than T2 is not less than T3.

TABLE 1

Channel quality Q of a through link	Duration of timer
		Q1≤Q<Q2	T1 or Range1
Q2≤Q<Q3	T2 or Range2
		Q3≤Q≤Q4	T3 or Range3

Alternatively, if different through link channel qualities Q correspond to different timer duration ranges, such as Range1, Range2, and Range3, where the value of Range3 may be greater than or equal to the value of Range2, the value of Range2 may be greater than or equal to the value of Range1, or the values of Range1, Range2, and Range3 may also overlap. The first terminal may determine the channel quality of the through link from the received RLM signal before starting the timer. For example, the channel quality of the through link may be determined by the signal-to-noise ratio, the reception probability, or other channel parameters of the signal of the through link. The first terminal selects a value among any one of Range1, Range2, or Range3 as the duration of the timer according to the determined channel quality of the through link.

In other embodiments, the correspondence between the synchronization source type and the duration of the timer may be preconfigured, specified by network device configuration or communication protocol. The synchronization source type includes, but is not limited to, one of an LTE base station eNB, an NR base station gNB, a GNS satellite signal, other terminals, and the like. The setting manner of the corresponding relationship is similar to the setting manner of the corresponding relationship between the channel quality of the direct link and the duration of the timer, and is not described herein again.

In other embodiments, the correspondence between the accuracy of the synchronization source and the duration of the timer may be preconfigured, specified by network device configuration or communication protocol. The synchronization source precision may be expressed in pps, with different precision for different synchronization source types. For example, the higher the accuracy of the synchronization source, the longer the duration of the corresponding timer, and the lower the accuracy of the synchronization source, the shorter the duration of the corresponding timer.

In other embodiments, the correspondence between the speed of the first terminal and the duration of the timer may be preconfigured, specified by network device configuration or communication protocol. The slower the speed of the first terminal is, the more stable the link state is, the longer the duration of the corresponding timer is, and the faster the speed of the first terminal is, the shorter the duration of the corresponding timer is.

In other embodiments, the correspondence between the speed of the second terminal and the duration of the timer may be preconfigured, specified by network device configuration or communication protocol. The slower the speed of the second terminal is, the more stable the link state is, the longer the duration of the corresponding timer is, and the faster the speed of the second terminal is, the shorter the duration of the corresponding timer is.

In other embodiments, the correspondence between the relative speed between the first terminal and the second terminal and the duration of the timer may be preconfigured, specified by network device configuration or communication protocol. The smaller the relative speed between the first terminal and the second terminal is, the more stable the link state is, the longer the duration of the corresponding timer is, and the larger the relative speed between the first terminal and the second terminal is, the shorter the duration of the corresponding timer is.

In other embodiments, the correspondence between the distance between the first terminal and the second terminal and the duration of the timer may be preconfigured, specified by network device configuration or communication protocol. The closer the distance between the first terminal and the second terminal is, the more stable the link state is, the longer the duration of the corresponding timer is, and the longer the distance between the first terminal and the second terminal is, the shorter the duration of the corresponding timer is.

In further embodiments, the duration of the timer may be determined based on a combination of a link state of the through link, a channel quality of the through link, a synchronization source type, a synchronization source accuracy, a speed of the first terminal in the through link, a speed of the second terminal in the through link, a relative speed between the first terminal and the second terminal in the through link, and a distance between the first terminal and the second terminal in the through link.

For example, a correspondence relationship between a combination of a link state of the through link and a channel quality of the through link and a time length of the timer may be set, as shown in table 2, when the link state of the through link is the OOS state, if the channel quality Q of the through link is greater than or equal to Q1 and less than Q2, the time length of the corresponding timer is T1 or Range1, if the channel quality Q of the through link is greater than or equal to Q2 and less than Q3, the time length of the corresponding timer is T2 or Range2, and if the channel quality Q of the through link is greater than or equal to Q3 and less than or equal to Q4, the time length of the corresponding timer is T3 or Range 3. When the link state of the through link IS the IS state, if the channel quality Q of the through link IS greater than or equal to Q1 and less than Q2, the duration of the corresponding timer IS T4 or Range4, if the channel quality Q of the through link IS greater than or equal to Q2 and less than Q3, the duration of the corresponding timer IS T5 or Range5, and if the channel quality Q of the through link IS greater than or equal to Q3 and less than or equal to Q4, the duration of the corresponding timer IS T6 or Range 6. Wherein T1 is not less than T2 is not less than T3 is not less than T4 is not less than T5 is not less than T6.

TABLE 2

Alternatively, if the combination of the link status of the different through links and the channel quality of the through links corresponds to different timer duration ranges, such as Range1, Range2, Range3, Range4, Range5, and Range6, wherein the values of Range1, Range2, Range3, Range4, Range5, and Range6 may be different, or the values of Range1, Range2, Range3, Range4, Range5, and Range6 may also overlap. Before starting the timer, the first terminal determines a link state of the through link and a channel quality of the through link, and selects a value in any one of Range1, Range2, Range3, Range4, Range5, and Range6 as a duration of the timer according to the determined link state of the through link and the channel quality of the through link.

In other embodiments, the corresponding relationship between the combination of other parameters and the duration of the timer may also be set, and the specific setting manner may refer to table 2, which is not described herein again.

In an alternative embodiment, the physical layer of the first terminal starts a timer and determines that the link status of the through link is unchanged during the running of said timer. In this embodiment, the timer start condition is that the physical layer receives an RLM signal for the through link. As shown in fig. 4, the method for monitoring the link status of the direct link according to this embodiment includes the following steps:

in step S401, the physical layer of the first terminal receives the RLM signal of the direct link.

Step S402, the physical layer determines the link state of the straight-through link according to the received RLM signal and starts a timer corresponding to the straight-through link.

Wherein, the RLM signal may include one or more of the following signals: PSCCH (direct link Physical shared Channel) signal, PSCCH (direct link Physical Control Channel) signal, PSFCH (Physical link feedback Channel) signal, SCI (direct link Control Information) signal, HARQ (Hybrid Automatic Repeat Request) signal, CSI-RS (Channel state Information Reference signal), DMRS (Demodulation Reference Symbol), and the like.

For example, when UE1 is in direct communication with UE2, the physical layer of UE1 receives RLM signals of the direct link between UE1 and UE2 from which the link state of the direct link between UE1 and UE2 can be determined. Specifically, from the RLM signal, a radio link quality value of the direct link between the UE1 and the UE2 may be obtained, which may be, but is not limited to, a signal-to-noise ratio, a reception probability, and the like of the link. And comparing the obtained wireless link quality value with a set quality threshold value to determine the link state of the direct link, wherein the quality threshold value can be configured by the network equipment. If the obtained wireless link quality value IS greater than or equal to the quality threshold, the link state of the through link may be considered to be an IS state, and if the obtained wireless link quality value IS less than the quality threshold, the link state of the through link may be considered to be an OOS state. The specific process of determining the link state of the direct link by the physical layer of the UE1 according to the received RLM signal may be performed with reference to the method for determining the link state of the downlink by the Uu interface, and is not described herein again.

The physical layer of the UE1 receives the RLM signal of the direct link between the UE1 and the UE2, that is, it is determined that the timer start condition is satisfied, and a timer corresponding to the direct link between the UE1 and the UE2 is started according to the duration of the timer.

The timer duration method may be determined using one of the timer duration determination methods described above. For example, the duration of the timer may be determined according to the determined link status of the through link, and if the link status of the through link IS the IS status, the duration of the timer may be determined as T1, and if the link status of the through link IS the OOS status, the duration of the timer may be determined as T2. Among them, T1 may be at least T2.

It should be noted that the UE1 may be in direct communication with multiple terminals such as the UE2 and the UE3 at the same time, and the physical layer of the UE1 receives the RLM signal of the direct link between the UE1 and the UE2, and then starts a timer corresponding to the direct link between the UE1 and the UE 2. The physical layer of the UE1 receives the RLM signal of the direct link between the UE1 and the UE3, and starts a timer corresponding to the direct link between the UE1 and the UE 3.

Step S403, the physical layer reports the determined link state of the direct link to the access layer of the first terminal according to the set link state reporting period.

The periodic reporting process can be seen in fig. 5. And during the running period of the timer, the physical layer reports the determined link state of the straight-through link to an access layer of the first terminal according to a set link state reporting period. For example, if the determined link state IS the IS state, the physical layer reports the link state of the direct link to the access layer as the IS state once every other link state reporting period during the running period of the timer. If the determined link state is an OOS state, the physical layer reports the link state of the straight-through link to the access layer once every other link state reporting period during the running period of the timer, wherein the link state of the straight-through link is the OOS state.

The reporting period is configured or preconfigured by a network, or configured by another terminal, or autonomously determined by the terminal.

As shown in fig. 6, if the access layer receives N OOS statuses continuously reported by the physical layer, the timer T is started_NAt the timer T_NDuring the operation, if the access layer continuously receives M IS states reported by the physical layer, the timer T IS stopped_NAnd continuously receiving the link state of the straight-through link reported by the physical layer. If the timer T_NAnd if the time IS out and the access layer does not receive the M IS states continuously reported by the physical layer, the access layer determines that the direct link connection fails, triggers the RLF process and starts the RRC connection reestablishment process. For example, the access layer may issue an RLF declaration to the NAS layer so that the NAS layer restarts the direct communication establishment procedure or does not start the direct communication establishment procedure, and optionally, the access layer releases resources corresponding to the direct link, such as a communication context.

Step S404, the physical layer judges whether the RLM signal of the straight-through link is received again; if yes, returning to execute the step S402; if not, step S405 is performed.

As shown in fig. 7, if the physical layer receives the RLM signal of the direct link again during the operation of the Timer1, the link state of the direct link is determined again according to the newly received RLM signal of the direct link, the Timer1 is stopped, and a new Timer2 corresponding to the direct link is started. And reporting the re-determined link state to the access stratum according to a set link state reporting period during the running period of the Timer 2. The duration of the Timer1 may be equal to or different from the duration of the Timer 2.

Step S405, the physical layer judges whether the timer runs over; if not, returning to execute the step S403; if so, go to step S406.

And if the physical layer does not receive the RLM signal of the through link, judging whether the running of the timer is finished. And when the timer is not operated completely, reporting the link state of the straight-through link to the access layer according to the set link state reporting period.

Step S406, the physical layer reports the link state of the direct link to the access layer of the first terminal as an uncertain state according to the set link state reporting period.

If the timer is finished and the physical layer of the first terminal does not receive a new RLM signal, the physical layer determines that the link state of the through link is an uncertain state, may or may not start the new timer, and reports the link state of the through link to the access layer of the first terminal as the uncertain state according to the set link state reporting period.

And during the period of reporting that the link state is the uncertain state, if the physical layer receives the RLM signal of the straight-through link again, returning to the step S402, re-determining the link state of the straight-through link according to the newly received RLM signal of the straight-through link, starting a new timer, and continuously monitoring the link state of the straight-through link.

And if the access layer continuously receives the N uncertain states reported by the physical layer, the access layer determines that the direct link fails to be connected and triggers the RLF process. For example, the access stratum may issue an RLF assertion to the NAS layer to cause the NAS layer to restart the direct communication setup procedure or not. Optionally, the access layer no longer monitors the link state of the direct link, and releases resources, such as a communication context, corresponding to the direct link.

In another alternative embodiment, the access stratum of the first terminal starts a timer and determines that the link state of the through link is unchanged during the operation of the timer. In this embodiment, the timer starting condition is that the access layer receives a link state of the direct link reported by the physical layer of the first terminal. As shown in fig. 8, the method for monitoring the link status of the direct link according to this embodiment includes the following steps:

step S801, the access layer of the first terminal receives the link status reported by the physical layer of the first terminal.

Step S802, the access layer of the first terminal takes the link status reported by the physical layer as the link status of the direct link and starts a timer corresponding to the direct link.

For example, when the UE1 directly communicates with the UE2, the physical layer of the UE1 receives an RLM signal of the direct link between the UE1 and the UE2, determines the link state of the direct link between the UE1 and the UE2 according to the RLM signal, and reports the link state of the direct link to the access layer of the UE 1. Since the RLM signal of the direct link between UE1 and UE2 may be aperiodic, the physical layer of UE1 may report the link state of the direct link to the access layer of UE1 aperiodically.

The access layer of the UE1 receives the link state of the direct link reported by the physical layer of the UE1, that is, it is determined that the timer start condition is satisfied, and a timer corresponding to the direct link between the UE1 and the UE2 is started according to the duration of the timer.

The timer duration method may be determined using one of the timer duration determination methods described above. For example, the duration of the timer may be determined according to the link status of the through link, and if the link status of the through link IS the IS status, the duration of the timer may be determined to be T1, and if the link status of the through link IS the OOS status, the duration of the timer may be determined to be T2. Among them, T1 may be at least T2.

Step S803, the access layer determines that the link state of the direct link is unchanged according to the set link state reporting period.

As shown in fig. 9. During the timer running, the access stratum periodically maintains the link state of the through link. For example, if the link state reported by the physical layer IS the IS state, the access layer determines that the link state of the direct link IS the IS state once every other link state reporting period during the running period of the timer. If the link state reported by the physical layer is an OOS state, the access layer determines that the link state of the straight-through link is the OOS state once every other link state reporting period during the running period of the timer.

If the access layer continuously determines N OOS states, a timer T is started_NAt the timer T_NDuring the operation, if the access layer continuously receives that the physical layer reports that the link state of the straight-through link IS the IS state and continuously determines M IS states, the timer T IS stopped_NAnd continuously receiving the link state of the straight-through link reported by the physical layer and monitoring the link state of the straight-through link. If the timer T_NAnd if the time IS out and the access layer does not continuously determine the M IS states, the access layer determines that the direct link connection fails and triggers an RLF process. Optionally, the access layer releases the resource corresponding to the direct link.

Step S804, the access layer judges whether a new link state of the straight-through link reported by the physical layer is received again; if yes, returning to execute the step S802; if not, step S805 is performed.

As shown in fig. 10, if the access stratum receives the new link state of the direct link reported by the physical layer again during the operation of the Timer3, the new link state reported by the physical layer is used as the new link state of the direct link, the Timer3 is stopped, and the new Timer4 corresponding to the direct link is started. And during the running period of the Timer4, determining that the new link state of the through link is unchanged according to a set link state reporting period. The duration of the Timer3 may be equal to or different from the duration of the Timer 4.

Step S805, the access stratum judges whether the timer runs over; if not, returning to execute the step S803; if so, step S806 is performed.

And if the access layer does not receive the new link state of the straight-through link reported by the physical layer, judging whether the running of the timer is finished. And when the timer is not operated, determining that the link state of the straight-through link is unchanged according to the set link state reporting period.

Step S806, the access layer determines that the link state of the direct link is an uncertain state according to the set link state reporting period.

And if the timer is finished and the access layer of the first terminal does not receive the new link state of the straight-through link reported by the physical layer, the access layer determines that the link state of the straight-through link is an uncertain state according to a set link state reporting period.

Step S807, the access layer judges whether a new link state of the straight-through link reported by the physical layer is received again; if yes, returning to execute the step S802; if not, step S808 is performed.

And when the link state is determined to be the uncertain state, if the access layer receives the new link state of the straight-through link reported by the physical layer again, the step S802 is returned to be executed, the received new link state of the straight-through link is determined to be the link state of the straight-through link again, a new timer is started, and the link state of the straight-through link is continuously monitored.

Step S808, the access layer judges that the continuous times of determining that the link state of the straight-through link is the uncertain state reach the set number; if yes, go to step S809, if no, go back to step S806.

Step S809, the access layer determines that the direct link connection fails.

If the continuous times that the access layer determines that the link state of the direct link is the uncertain state reach the set number, which may be N times, the access layer determines that the direct link fails to be connected, and triggers the RLF process. For example, the access layer may issue an RLF declaration to the NAS layer, so that the NAS layer restarts or does not start the direct communication establishment procedure, and optionally, the access layer no longer monitors the link status of the direct link and releases the resource corresponding to the direct link.

According to the method for monitoring the link state of the straight-through link, the first terminal is provided with the timer, after the link state of the straight-through link between the first terminal and the second terminal is determined, the timer corresponding to the straight-through link is started according to the starting condition of the timer, and the link state of the straight-through link is determined to be unchanged during the running period of the timer. Through the above manner, even if no periodic RLM signal is available for measurement or monitoring on the direct link, the first terminal may periodically determine that the link state of the direct link is unchanged according to the link state of the direct link determined when the timer is started, thereby implementing monitoring of the direct link state.

Based on the same inventive concept, the embodiment of the present application further provides a terminal, and since the terminal corresponds to the method for monitoring the link state of the direct link provided in the embodiment of the present application, and the principle of the terminal for solving the problem is similar to that of the method, the implementation of the terminal may refer to the implementation of the method, and repeated details are not repeated.

As shown in fig. 11, a terminal provided in an embodiment of the present application includes a processor 1100, a memory 1101, and a transceiver 1102;

the processor 1100 is responsible for managing the bus architecture and general processing, and the memory 1101 may store data used by the processor 1100 in performing operations. The transceiver 1102 is used to receive and transmit data under the control of the processor 1100.

The bus architecture may include any number of interconnected buses and bridges, with various circuits specifically represented by one or more of processor 1100 and memory represented by memory 1101 linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The processor 1100 is responsible for managing the bus architecture and general processing, and the memory 1101 may store data used by the processor 1100 in performing operations.

The processes disclosed in the embodiments of the present application can be applied to the processor 1100, or implemented by the processor 1100. In implementation, the steps of the signal processing flow may be performed by integrated logic circuits of hardware or instructions in the form of software in the processor 1100. The processor 1100 may be a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like that implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present application. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present application may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in a processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 1101, and the processor 1100 reads information in the memory 1101, and completes the steps of the signal processing flow in combination with hardware thereof.

Specifically, the processor 1100 is configured to read a program in the memory 1101 and execute:

In one possible implementation, the processor 1100 specifically performs:

In a possible implementation manner, the timer starting condition is that a physical layer of the first terminal receives an RLM signal of the direct link, and the processor 1100 specifically performs:

In one possible implementation, the processor 1100 further performs:

In a possible implementation manner, the timer starting condition is that the access layer of the first terminal receives a link state of the direct link reported by the physical layer of the first terminal, and the processor 1100 specifically executes:

In one possible implementation, the processor 1100 further performs:

The terminal is provided with a timer, after the link state of a direct link between the terminal and another terminal is determined, the timer corresponding to the direct link is started according to the starting condition of the timer, and the link state of the direct link is determined to be unchanged during the running period of the timer. Through the mode, even if no periodic RLM signal is available for measurement on the through link, the terminal can periodically determine that the link state of the through link is unchanged according to the link state of the through link determined when the timer is started, and further monitor the link state of the through link.

As shown in fig. 12, a terminal according to an embodiment of the present application includes:

a timer starting unit 1201, configured to determine a link state of a direct link between the second terminal and the second terminal, and start a timer corresponding to the direct link according to a timer starting condition;

a link status determining unit 1202, configured to determine that a link status of the through link is unchanged during the running of the timer.

In a possible implementation manner, the timer starting unit 1201 is further configured to:

In a possible implementation manner, the timer starting condition is that a physical layer of the first terminal receives an RLM signal of the direct link, and the timer starting unit 1201 is further configured to:

In a possible implementation manner, the link status determining unit 1202 is further configured to:

In a possible implementation manner, the timer starting condition is that an access layer of the first terminal receives a link state of a direct link reported by a physical layer of the first terminal, and the timer starting unit 1201 is further configured to:

The embodiment of the application also provides a computer-readable storage medium for the link state monitoring method of the through link, namely, the content is not lost after power failure. The storage medium stores therein a software program, including program code, which when executed on a computing device is read and executed by one or more processors implements an aspect of any one of the above link state monitoring methods of the embodiments of the present application.

Embodiments of the present application are described above with reference to block diagrams and/or flowchart illustrations of methods, apparatus (systems) and/or computer program products according to embodiments of the application. It will be understood that one block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, and/or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, create means for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.

Accordingly, embodiments of the present application may also be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.). Furthermore, embodiments of the present application may take the form of a computer program product on a computer-usable or computer-readable storage medium having computer-usable or computer-readable program code embodied in the medium for use by or in connection with an instruction execution system. In the context of embodiments of the present application, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A method for monitoring link status of a direct link, the method comprising:

2. The method of claim 1, wherein the first terminal starting the timer according to a timer starting condition comprises:

3. The method of claim 1, wherein the timer start condition is that a Radio Link Monitoring (RLM) signal of the through link is received by a physical layer of the first terminal or a link state of the through link reported by the physical layer of the first terminal is received by an access layer of the first terminal.

4. The method of claim 3, wherein the timer start condition is that a physical layer of the first terminal receives an RLM signal of the direct link, the first terminal determining a link state of the direct link with a second terminal, comprising:

5. The method of claim 4, wherein the method further comprises:

6. The method of claim 4 or 5, wherein the method further comprises:

7. The method of claim 3, wherein the timer starting condition is that an access layer of the first terminal receives a link state of a direct link reported by a physical layer of the first terminal, and the determining, by the first terminal, the link state of the direct link with a second terminal comprises:

8. The method of claim 7, wherein the method further comprises:

9. The method of claim 1, wherein the first terminal determines the duration of the timer corresponding to the through link by:

10. The method of claim 9, wherein the state parameters of the through link comprise one or a combination of the following parameters:

11. A terminal, comprising: a processor and a memory;

12. The terminal of claim 11, wherein the processor is further operative to:

13. The terminal of claim 11, wherein the timer start condition is that a Radio Link Monitoring (RLM) signal of the direct link is received by a physical layer of the first terminal or a link state of the direct link reported by a physical layer of the first terminal is received by an access layer of the first terminal.

14. The terminal of claim 13, wherein the timer start condition is that the RLM signal for the direct link is received by a physical layer of the first terminal, and wherein the processor is further configured to:

15. The terminal of claim 14, wherein the processor further performs:

16. The terminal of claim 14 or 15, wherein the processor further performs:

17. The terminal of claim 13, wherein the timer starting condition is that an access layer of the first terminal receives a link status of a direct link reported by a physical layer of the first terminal, and the processor specifically executes:

18. The terminal of claim 17, wherein the processor further performs:

19. The terminal of claim 11, wherein the processor further performs:

20. The terminal of claim 19, wherein the status parameters of the through link include one or a combination of the following parameters:

21. A terminal, comprising: