CN105636191B

CN105636191B - A kind of synchronisation source selection method and system, base station, terminal

Info

Publication number: CN105636191B
Application number: CN201410643294.XA
Authority: CN
Inventors: 凌为
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2014-11-07
Filing date: 2014-11-07
Publication date: 2019-02-05
Anticipated expiration: 2034-11-07
Also published as: CN105636191A

Abstract

The invention discloses a kind of synchronisation source selection method and system, base station, terminals, which comprises when the status information for detecting itself is unsatisfactory for the first preset condition, first terminal sends the first request message to first terminal set；The first terminal receives the first response message that the first terminal set is sent, and first response message carries the first information of the first terminal set itself；When the first terminal detects its own in the coverage area of base station, the first terminal judges the terminal whether having in the first terminal own base station coverage area in the first terminal set according to the first information, obtains the first judging result；When first judging result shows the first terminal set not in the first terminal own base station coverage area, the first terminal selects a terminal as second terminal from second terminal set.

Description

A kind of synchronisation source selection method and system, base station, terminal

Technical field

The present invention relates to electronic technology more particularly to a kind of synchronisation source selection methods and system, base station, terminal.

Background technique

In mobile communications, communication can occur user equipment (UE, User Equipment, or also referred to as terminal, Or user terminal) and application server (AS, Application Server) between, it is also possible to occur two user equipmenies it Between.Communication between two user equipmenies may pass through AS transfer, it is also possible to by end to end between two user equipmenies IP traffic carry out, the latter i.e. be referred to as direct-connected communication (D2D communication, Direct to Direct Communication), the end-to-end communication wherein direct-connected communication is otherwise known as.

Fig. 1-1 is direct-connected communication (D2D, Direct to Direct) network architecture diagram in the related technology, such as Fig. 1-1 institute Show, which includes two UE, the radio reception device connecting with UE, the network equipment and Home Environment；Wherein, two UE (UE1 and UE2) can direct-connected communication finds and carries out direct-connected communication mutually, and radio reception device can be evolved base station (eNB), the network equipment can be mobility management entity (MME, Mobility Management Entity), and Home Environment can To include home subscriber server (HSS, Home Subscriber Server), access network discovery and selection function unit (ANDSF, Access Network Discovery and Selection Function), application server, gateway proxy Equipment such as (P-GW, Gateway Proxy).

UE in direct-connected communication can be using base station as the synchronisation source of time, can also be same using another UE as its time Step source；When the synchronisation source using another UE as the time, since the UE (hereinafter referred to as synchronisation source UE) as synchronisation source needs Periodically synchronization sequence signals, therefore, the battery consumption of the UE as synchronisation source are sent to by the UE of synchronisation source of own Can accelerate, if the UE as synchronisation source serves as always the synchronisation source of other UE, as synchronisation source UE therefore and power consumption is tight Weight, greatly shortens stand-by time.At the same time, synchronous UE can need again because of the out of power of the UE as synchronisation source Synchronisation source is found, resource is reconfigured.As it can be seen that it is now this after the UE as synchronisation source is out of power, and reconfigure money Source is similar to the hard handover of primary direct-connected communication synchronisation source, and this hard handover is detrimental to the stability of direct-connected communication transfer.

Summary of the invention

In view of this, the embodiment of the present invention be solve the problems, such as it is existing in the prior art at least one and a kind of synchronization is provided Source selection method and system, base station, terminal.

The technical solution of the embodiment of the present invention is achieved in that

In a first aspect, the embodiment of the present invention provides a kind of synchronisation source selection method, it is applied to first terminal, described first eventually End is as the synchronous source terminal in source, which comprises

When detecting itself status information and being unsatisfactory for the first preset condition, first terminal sends the to first terminal set One request message；

Wherein, the first terminal collection is combined into the terminal apart from the first terminal in preset first distance threshold value, The first information of first request message for first terminal set described in request；

The first terminal receives the first response message that the first terminal set is sent, and first response message is taken The first information with the first terminal set itself；

When the first terminal detects its own in the coverage area of base station, the first terminal is according to described first Information judges the terminal for whether having in the first terminal own base station coverage area in the first terminal set, obtains One judging result；

When first judging result shows that the first terminal set does not cover in the first terminal own base station When in range, the first terminal selects a terminal as second terminal from second terminal set,

Wherein, the second terminal is new synchronization source terminal, and the second terminal collection is combined into apart from the first terminal Terminal in preset second distance threshold range.

Second aspect, the embodiment of the present invention provide a kind of synchronisation source selection method, are applied to second terminal, the method packet It includes:

The second terminal receives the first request message that first terminal is sent, wherein the first terminal is same as source Source terminal is walked, first request message is used to request the first information of the second terminal；

The second terminal sends the first response message to the first terminal, includes itself in first response message The first information；

The second terminal receives the second request message, and second request message is for requesting the second terminal conduct New synchronisation source；

The second terminal executes synchronisation source function.

The third aspect, the embodiment of the present invention provide a kind of synchronisation source selection method, which comprises

Base station receives the switching synchronisation source request that first terminal is sent, and the switching synchronisation source request carries the 5th terminal The identification information of set, the 5th termination set are combined into alternative synchronisation source terminal set；

The base station determines second terminal according to first distance and second distance in the 5th terminal set；

Wherein, the first distance is the distance between first terminal described in the base station distance, and the second distance is The distance between terminal in 5th terminal set described in the base station distance；

The base station sends the second request message to the second terminal according to the identification information of the second terminal, described Second request message is for requesting the second terminal as new synchronisation source.

Fourth aspect, the embodiment of the present invention provide a kind of first terminal, and the first terminal is as the synchronous source terminal in source, institute Stating first terminal includes the first transmission unit, the first receiving unit, judging unit and first selecting unit, in which:

First transmission unit, for when detecting itself status information and being unsatisfactory for the first preset condition, to first Terminal set sends the first request message；

First receiving unit, the first response message sent for receiving the first terminal set, described first Response message carries the first information of the first terminal set itself；

The judging unit, for when the first terminal detects its own in the coverage area of base station, according to institute It states the first information and judges the terminal for whether having in the first terminal own base station coverage area in the first terminal set, Obtain the first judging result；

The first selecting unit, for showing the first terminal set not described when first judging result When in first terminal own base station coverage area, the first terminal selects a terminal as second from second terminal set Terminal,

5th aspect, the embodiment of the present invention provide a kind of second terminal, and the second terminal includes the 4th receiving unit, the Four transmission units, the 6th receiving unit and execution unit, in which:

4th receiving unit, for receiving the first request message of first terminal transmission, wherein the first terminal As the synchronous source terminal in source, first request message is used to request the first information of the second terminal；

4th transmission unit, for sending the first response message, first response message to the first terminal In include itself the first information；

6th receiving unit, for receiving the second request message, second request message is for requesting described the Two terminals are as new synchronisation source；

The execution unit, for executing synchronisation source function.

6th aspect, the embodiment of the present invention provide a kind of base station, the base station include the 5th receiving unit, determination unit and 5th transmission unit, in which:

5th receiving unit, for receiving the switching synchronisation source request of first terminal transmission, the switching synchronisation source Request carries the identification information of the 5th terminal set, and the 5th termination set is combined into alternative synchronisation source terminal set；

The determination unit, for determining that second is whole in the 5th terminal set according to first distance and second distance End；

5th transmission unit, for sending second to the second terminal according to the identification information of the second terminal Request message, second request message is for requesting the second terminal as new synchronisation source.

7th aspect, the volume embodiment of the present invention provide a kind of synchronisation source selection system, the system comprises first terminal and Second terminal, wherein the first terminal includes the first transmission unit, the first receiving unit, judging unit, first selecting unit With the 4th selecting unit, the second terminal includes the 4th receiving unit and the 4th transmission unit, in which:

The first selecting unit, for showing the first terminal set not described when first judging result When in first terminal own base station coverage area, select a terminal as second terminal from second terminal set；

4th selecting unit, for when the first terminal detects its own not in the coverage area of base station, Select a terminal as second terminal from second terminal set；

The embodiment of the present invention provides a kind of synchronisation source selection method and system, base station, terminal, wherein when detecting itself When status information is unsatisfactory for the first preset condition, first terminal sends the first request message to first terminal set；Described first Terminal receives the first response message that the first terminal set is sent；When the first terminal detects its own covering in base station When within the scope of lid, the first terminal judges whether have in the first terminal set described first according to the first information Terminal in terminal own base station coverage area, obtains the first judging result；When first judging result shows described first Terminal set not in the first terminal own base station coverage area when, the first terminal is selected from second terminal set A terminal is selected as second terminal, so, it is possible to make the switching between synchronisation source to become a kind of soft handover, so that direct-connected communication Transmission network is more stable.

Detailed description of the invention

Fig. 1-1 is the network architecture diagram of direct-connected communication in the related technology；

Fig. 1-2 is the implementation process schematic diagram of one synchronisation source selection method of the embodiment of the present invention；

Fig. 2 is the implementation process schematic diagram of two synchronisation source selection method of the embodiment of the present invention；

Fig. 3 is the implementation process schematic diagram of three synchronisation source selection method of the embodiment of the present invention；

Fig. 4 is the implementation process schematic diagram of four synchronisation source selection method of the embodiment of the present invention；

Fig. 5 is the implementation process schematic diagram of five synchronisation source selection method of the embodiment of the present invention；

Fig. 6 is the implementation process schematic diagram of six synchronisation source selection method of the embodiment of the present invention；

Fig. 7 is the implementation process schematic diagram of seven synchronisation source selection method of the embodiment of the present invention；

Fig. 8 is the composed structure schematic diagram that eight synchronisation source of the embodiment of the present invention selects system；

Fig. 9 is the composed structure schematic diagram that nine synchronisation source of the embodiment of the present invention selects system；

Figure 10 is the composed structure schematic diagram that ten synchronisation source of the embodiment of the present invention selects system；

Figure 11 is the composed structure schematic diagram that 11 synchronisation source of the embodiment of the present invention selects system；

Figure 12 is the composed structure schematic diagram that 12 synchronisation source of the embodiment of the present invention selects system.

Specific embodiment

The technical solution of the present invention is further elaborated in the following with reference to the drawings and specific embodiments.

Embodiment one

The embodiment of the present invention provides a kind of synchronisation source selection method, and Fig. 1-2 is one synchronisation source selecting party of the embodiment of the present invention The implementation process schematic diagram of method, as shown in Figs. 1-2, this method are applied to synchronisation source and select system, which includes several ends End, base station, wherein the UE in direct-connected communication is made below with first terminal as time synchronization source (referred to as synchronous source terminal) Source terminal is synchronized for source, this method comprises:

Step 100, whether the status information that the first terminal detects itself meets the first preset condition；

Here, the status information that the first terminal detects itself whether meet the first preset condition can there are many realize The modes of two kinds of specific implementations are provided below in mode, and first way, itself the status information includes information about power, right Ying Di, the step 100 are as follows: whether the information about power that the first terminal detects itself meets preset battery condition；Second Kind of mode, itself the status information includes signal strength, accordingly, the step 100 are as follows: the first terminal detection from Whether the signal strength of body meets preset signal strength conditions.

Step 101, when detecting itself status information and being unsatisfactory for the first preset condition, first terminal is to first terminal collection It closes and sends the first request message；

Corresponding to the two kinds of specific implementations provided in step 100, first way: when the status information of detection itself When being unsatisfactory for the first preset condition are as follows: when detecting itself information about power and being unsatisfactory for preset battery condition, first terminal to First terminal set sends the first request message；The second way: when the signal strength for detecting itself is unsatisfactory for preset signal When strength condition, first terminal sends the first request message to first terminal set.Wherein, the first terminal collection is combined into described Terminal near first terminal, specifically, the first terminal collection are combined into apart from the first terminal in preset first distance Terminal in threshold value, the first information of first request message for first terminal set described in request；

Here, whether the first information may include path loss information and the terminal in base station range Information, user identifier (ID) information and when the terminal is in coverage area serving BS belonging to the base station mark letter Breath, information about power etc..

Step 102, the first terminal set receives first request message；

Here, the first terminal set includes second terminal.

Step 103, it is based on first request message, the first terminal set sends the first sound to the first terminal Answer message；

It here, include the first information of itself in first response message.

Step 104, the first terminal receives the first response message that the first terminal set is sent；

Here, first response message carries the first information of the first terminal set itself；

Step 105, when the first terminal detects its own in the coverage area of base station, the first terminal according to The first information judges the end for whether having in the first terminal own base station coverage area in the first terminal set End, obtains the first judging result；

Step 106, when first judging result shows the first terminal set not belonging to the first terminal When in base station range, the first terminal selects a terminal as second terminal from second terminal set；

Here, the second terminal is new synchronization source terminal, and the second terminal collection is combined into apart from the first terminal Terminal in preset second distance threshold range.The first distance threshold value can be identical with the second distance threshold value, It can also be different.

Here, the first terminal selects a terminal as second terminal, including a variety of choosings from second terminal set Select mode, for example, first terminal can from be selected in second terminal set one apart from nearest terminal as second terminal, When there are multiple terminals apart from the first terminal when being equidistant and is minimum, the first terminal can be randomly selected one Terminal is as second terminal.For another example, first terminal can be selected from second terminal set the highest terminal of electricity as Second terminal；For another example, first terminal can select the maximum terminal of signal strength as second from second terminal set Terminal.Certainly, first terminal can also integrate various above-mentioned various selection modes, for example, first terminal is first from second terminal Terminal of the signal strength greater than preset threshold is selected in set as the first subclass, is then selected from the first subclass again It is out second terminal apart from nearest terminal.Those skilled in the art can select from second terminal set as the case may be Second terminal is selected, the embodiment of the present invention is limited not to this.

Step 107, the first terminal sends the second request message to the second terminal；

Here, second request message is for requesting the second terminal as new synchronization source terminal.

Step 108, the second terminal receives the second request message that the first terminal is sent；

Here, second request message is for requesting the second terminal as new synchronisation source, it is preferable that described the Two request messages include the second information needed for becoming synchronisation source；

It here, include System Frame Number (DFN), time division duplex (TDD, the Time of direct-connected communication in second information Division Duplexing) uplink and downlink proportion；In second information other than the uplink and downlink of DFN and TDD proportion, may be used also To include system bandwidth information, resource pool information etc..

Step 109, the second terminal executes synchronisation source function.

Preferably, the second terminal executes synchronisation source function according to second information.

In the embodiment of the present invention, the first terminal by serving as source synchronisation source detects the status information of itself, when itself When status information is unsatisfactory for the first preset condition, by sending the first request message to the terminal around the first terminal, so A suitable terminal (i.e. second terminal) is according to circumstances selected to continue to serve as synchronisation source afterwards, meanwhile, as source synchronisation source Second information needed for first terminal needs that synchronisation source will be become transfers new synchronization source terminal (i.e. second terminal) to, same in source It walks source terminal to complete after transferring with new synchronous source terminal, new synchronization source terminal works on the basis of the synchronisation source of source, source Synchronous source terminal is not acting as the role of synchronisation source.

Embodiment two

Based on embodiment one above-mentioned, the embodiment of the present invention provides a kind of synchronisation source selection method, and Fig. 2 is that the present invention is implemented The implementation process schematic diagram of two synchronisation source selection method of example, as shown in Fig. 2, this method, which is applied to synchronisation source, selects system, this is System includes several terminals, base station, wherein the UE in the direct-connected communication is as time synchronization source (referred to as synchronizing source terminal), under Face synchronous source terminal using first terminal as source, this method comprises:

Step 200, whether the status information that the first terminal detects itself meets the first preset condition；

Step 201, when detecting itself status information and being unsatisfactory for the first preset condition, first terminal is to first terminal collection It closes and sends the first request message；

Step 202, the first terminal set receives first request message；

Here, the first terminal set includes second terminal.

Step 203, the first terminal set judges whether the status information of itself meets the second preset condition, obtains Three judging results；

Here, second preset condition may be the same or different with first preset condition.

Step 204, when the third judging result shows that the status information meets the second preset condition, to described the One terminal sends first response message；

It here, include the first information of itself in first response message.Method documented by the present embodiment two is also wrapped It includes: when the third judging result shows that the status information is unsatisfactory for the second preset condition, not being sent out to the first terminal Send first response message.

Here, step 203 and step 204, actually first terminal, which are integrated into, receives the first of first terminal transmission After request message, first judge whether good enough the state of itself is, only when the state of itself is good enough, just to first Terminal sends the first response message.

In step 203, the first terminal set judge whether itself status information meets the second preset condition can There are many implementation, to be provided below the modes of two kinds of specific implementations, first way, itself the status information includes Information about power, accordingly, the step 203 are as follows: the first terminal set judges whether the electricity of itself is less than preset One power threshold obtains third judging result.The step 204 are as follows: when the third judging result shows that the electricity of itself is small When preset first power threshold, the first response message is not sent to the first terminal.And work as the third judging result When showing that the electricity of itself is more than or equal to preset first power threshold, the first response message is sent to the first terminal.

The second way, itself the status information includes signal strength, accordingly, the step 203 are as follows: described Whether the signal strength that one terminal detects itself meets preset signal strength conditions, obtains third judging result.Step 204 Are as follows: when the third judging result shows that itself signal strength meets preset signal strength conditions, eventually to described first End sends the first response message.When the third judging result shows that the signal strength of itself is unsatisfactory for preset signal strength item When part, the terminal in the first terminal set does not send the first response message to the first terminal.

Step 205, the first terminal receives the first response message that the first terminal set is sent；

Here, first response message carries the first information of the first terminal set itself；Described first eventually The electricity of terminal is all larger than equal to the first power threshold in the set of end.

Step 206, when the first terminal detects its own in the coverage area of base station, the first terminal according to The first information judges the end for whether having in the first terminal own base station coverage area in the first terminal set End, obtains the first judging result；

Step 207, when first judging result shows the first terminal set not belonging to the first terminal When in base station range, the first terminal selects a terminal as second terminal from second terminal set；

Step 208, the first terminal sends the second request message to the second terminal；

Step 209, the second terminal receives the second request message that the first terminal is sent；

Here, the uplink and downlink proportion of the System Frame Number in second information including direct-connected communication, time division duplex；Described It can also include system bandwidth information, resource pool information etc. in two information.

Step 210, the second terminal executes synchronisation source function.

In the embodiment of the present invention, the terminal in first terminal set first judges itself when receiving the first request message State be it is good enough, if the epidemic situation comparison of itself is good, when being suitble to do synchronisation source, just to first terminal transmission the One response message.Here, the terminal in first terminal set judges whether good enough the state of itself is, can pass through step 203 and step 204 provided by method realize.By step 203 and step 204 can guarantee to select as new same The second terminal in step source is the function that can bear synchronous source terminal.

Embodiment three

Based on embodiment one above-mentioned, the embodiment of the present invention provides a kind of synchronisation source selection method, and Fig. 3 is that the present invention is implemented The implementation process schematic diagram of three synchronisation source selection method of example, as shown in figure 3, this method, which is applied to synchronisation source, selects system, this is System includes several terminals, base station, wherein the UE in the direct-connected communication is as time synchronization source (referred to as synchronizing source terminal), under Face synchronous source terminal using first terminal as source, this method comprises:

Step 300, whether the status information that the first terminal detects itself meets the first preset condition；

Step 301, when detecting itself status information and being unsatisfactory for the first preset condition, first terminal is to first terminal collection It closes and sends the first request message；

Step 302, the first terminal set receives first request message；

Here, the first terminal set includes second terminal.

Step 303, first terminal set sends the first response message to the first terminal；

It here, include the first information of itself in first response message, the first information may include path damage Breath and the terminal of breaking one's promise whether information in base station range, user identity information and when the terminal is in coverage area The identification information of serving BS belonging to the base station, information about power etc. when interior.

Step 304, the first terminal receives the first response message that the first terminal set is sent；

Step 305, when the first terminal detects its own in the coverage area of base station, the first terminal according to The first information judges the end for whether having in the first terminal own base station coverage area in the first terminal set End, obtains the first judging result；

Step 306, when first judging result shows the first terminal set not belonging to the first terminal When in base station range, the first terminal makees the user equipment that information about power is more than or equal to preset second power threshold For third terminal set；

Step 307, the first terminal determines the second terminal set from the third terminal set；Described first Terminal selects a terminal as second terminal from the second terminal set.

Step 308, the first terminal sends the second request message to the second terminal；

Step 309, the second terminal receives the second request message that the first terminal is sent；

Step 310, the second terminal executes synchronisation source function.Preferably, the second terminal is according to second letter Breath executes synchronisation source function.

In the embodiment of the present invention, first terminal is first selected when receiving the first response message of first terminal set transmission Those itself state terminal (step 306) good enough is selected out to get to third terminal set.It can be protected by step 306 The second terminal as new synchronisation source selected is demonstrate,proved, is the function that can bear synchronous source terminal.

Example IV

Based on previous embodiment, the embodiment of the present invention provides a kind of synchronisation source selection method, and Fig. 4 is the embodiment of the present invention four The implementation process schematic diagram of synchronisation source selection method, as shown in figure 4, this method, which is applied to synchronisation source, selects system, the system packet Include several terminals, base station, wherein the UE in the direct-connected communication is as time synchronization source (referred to as synchronization source terminal), below with First terminal synchronizes source terminal as source, this method comprises:

Step 400, whether the status information that the first terminal detects itself meets the first preset condition；

Step 401, when detecting itself status information and being unsatisfactory for the first preset condition, first terminal is to first terminal collection It closes and sends the first request message；

Wherein, the first terminal collection is combined into the terminal near the first terminal, specifically, the first terminal set For the terminal apart from the first terminal in preset first distance threshold value, first request message is used for request institute State the first information of first terminal set；

Here, whether the first information may include path loss information and the terminal in base station range Information, user identity information and the identification information of serving BS belonging to the base station, electricity when the terminal is in coverage area Measure information etc..

Step 402, the first terminal set receives first request message；

Here, the first terminal set includes second terminal.

Step 403, it is based on first request message, the first terminal set sends the first sound to the first terminal Answer message；

It here, include the first information of itself in first response message.

Step 404, the first terminal receives the first response message that the first terminal set is sent；

Step 405, when the first terminal detects its own not in the coverage area of base station, the first terminal from Select a terminal as second terminal in second terminal set；

Step 406, the first terminal sends the second request message to the second terminal；

Step 407, the second terminal receives the second request message that the first terminal is sent；

Here, the System Frame Number in second information including direct-connected communication, time division duplex (uplink and downlink proportion；It is described Second information can also include system bandwidth information, resource pool information etc..

Step 408, the second terminal executes synchronisation source function.

Embodiment five

Based on previous embodiment, the embodiment of the present invention provides a kind of synchronisation source selection method, and Fig. 5 is the embodiment of the present invention five The implementation process schematic diagram of synchronisation source selection method, as shown in figure 5, this method, which is applied to synchronisation source, selects system, the system packet Include several terminals, base station, wherein the UE in the direct-connected communication is as time synchronization source (referred to as synchronization source terminal), below with First terminal synchronizes source terminal as source, this method comprises:

Step 500, whether the status information that the first terminal detects itself meets the first preset condition；

Step 501, when detecting itself status information and being unsatisfactory for the first preset condition, first terminal is to first terminal collection It closes and sends the first request message；

Step 502, the first terminal set receives first request message；

Here, the first terminal set includes second terminal.

Step 503, it is based on first request message, the first terminal set sends the first sound to the first terminal Answer message；

It here, include the first information of itself in first response message.

Step 504, the first terminal receives the first response message that the first terminal set is sent；

Step 505, when the first terminal detects its own in the coverage area of base station, the first terminal according to The first information judges the end for whether having in the first terminal own base station coverage area in the first terminal set End, obtains the first judging result；

Step 506, when first judging result shows to have in the first terminal set belonging to the first terminal When terminal in base station range, the first terminal obtains the 4th terminal according to the identification information of the first terminal set Set；

Here, the 4th termination set, which is combined into the first terminal set, covers model in the first terminal own base station Enclose interior terminal；

Step 507, the first terminal selects the 5th terminal set from the 4th terminal set；

Here, the 5th termination set be combined into alternative synchronisation source set and for apart from the first terminal preset the Terminal within the scope of three distance thresholds；

Here, the third distance threshold may be the same or different with the first distance threshold value.

Step 508, the first terminal sends switching synchronisation source request to itself own base station；

Here, the switching synchronisation source request includes at least the identification information of the 5th terminal set；

Step 509, the base station receives the switching synchronisation source request that first terminal is sent；

Here, the switching synchronisation source request carries the identification information of the 5th terminal set, the 5th terminal set For alternative synchronisation source terminal set, it is preferable that the switching synchronisation source request is also carried as the second letter needed for synchronisation source Breath；

Step 510, the base station determines that second is whole according to first distance and second distance in the 5th terminal set End；

Step 511, the base station sends the second request to the second terminal according to the identification information of the second terminal Message；

Here, second request message is for requesting the second terminal as new synchronisation source, it is preferable that described the Include the second information needed for becoming synchronisation source in two request messages.

Step 512, the second terminal receives the second request message that base station is sent；

Step 513, the second terminal executes synchronisation source function.

Embodiment six

Based on embodiment five above-mentioned, the embodiment of the present invention provides a kind of synchronisation source selection method, and Fig. 6 is that the present invention is implemented The implementation process schematic diagram of six synchronisation source selection method of example, as shown in fig. 6, this method, which is applied to synchronisation source, selects system, this is System includes several terminals, base station, wherein the UE in the direct-connected communication is as time synchronization source (referred to as synchronizing source terminal), under Face synchronous source terminal using first terminal as source, this method comprises:

Step 600, whether the status information that the first terminal detects itself meets the first preset condition；

Step 601, when detecting itself status information and being unsatisfactory for the first preset condition, first terminal is to first terminal collection It closes and sends the first request message；

Step 602, the first terminal set receives first request message；

Here, the first terminal set includes second terminal.

Step 603, it is based on first request message, the first terminal set sends the first sound to the first terminal Answer message；

It here, include the first information of itself in first response message.

Step 604, the first terminal receives the first response message that the first terminal set is sent；

Step 605, when the first terminal detects its own in the coverage area of base station, the first terminal according to The first information judges the end for whether having in the first terminal own base station coverage area in the first terminal set End, obtains the first judging result；

Step 606, when first judging result shows to have in the first terminal set belonging to the first terminal When terminal in base station range, the first terminal obtains the 4th terminal according to the identification information of the first terminal set Set；

Step 607, the first terminal selects the 5th terminal set from the 4th terminal set；

Step 608, the first terminal sends switching synchronisation source request to itself own base station；

Here, the switching synchronisation source request includes at least the identification information of the 5th terminal set, it is preferable that described Switching synchronisation source request is also carried as the second information needed for synchronisation source；

Step 609, the base station receives the switching synchronisation source request that first terminal is sent；

Here, the switching synchronisation source request carries the identification information of the 5th terminal set, the 5th terminal set For alternative synchronisation source terminal set；

Step 610, for each of the 5th terminal set terminal, the base station calculates first distance and second Apart from its difference, third distance is obtained；

Step 611, the smallest terminal of absolute value of the third distance is determined as second terminal by the base station.

Step 612, the base station sends the second request to the second terminal according to the identification information of the second terminal Message；

Step 613, the second terminal receives the second request message that base station is sent；

Step 614, the second terminal executes synchronisation source function.

Step 615, the base station sends to first terminal and releases synchronisation source message；

Here, the releasing synchronisation source message is for triggering the synchronisation source function that the first terminal releases itself.

Step 616, the first terminal receives the releasing synchronisation source message of itself own base station transmission；Based on the releasing Synchronisation source message releases the synchronisation source function of itself.

In the embodiment of the present invention, the step 615 and step 612,613 and step 614 have no stringent precedence relationship, walk Rapid 615 can be performed simultaneously with step 612, can also occur after step 612.

Embodiment seven

Based on previous embodiment, the embodiment of the present invention provides a kind of synchronisation source selection method, and Fig. 7 is the embodiment of the present invention seven The implementation process schematic diagram of synchronisation source selection method, as shown in fig. 7, this method, which is applied to synchronisation source, selects system, the system packet Include several terminals, base station, wherein the UE in the direct-connected communication is as time synchronization source (referred to as synchronization source terminal), below with First terminal synchronizes source terminal as source, this method comprises:

Step 700, whether the status information that the first terminal detects itself meets the first preset condition；

Step 701, when detecting itself status information and being unsatisfactory for the first preset condition, first terminal is to first terminal collection It closes and sends the first request message；

Step 702, the first terminal set receives first request message；

Here, the first terminal set includes second terminal.

Step 703, it is based on first request message, the first terminal set sends the first sound to the first terminal Answer message；

It here, include the first information of itself in first response message.

Step 704, the first terminal receives the first response message that the first terminal set is sent；

Step 705, when the first terminal detects its own in the coverage area of base station, the first terminal according to The first information judges the end for whether having in the first terminal own base station coverage area in the first terminal set End, obtains the first judging result；

Step 706, when first judging result shows to have in the first terminal set belonging to the first terminal When terminal in base station range, the first terminal obtains the 4th terminal according to the identification information of the first terminal set Set；

Step 707, the first terminal determines that described first is whole according to the information on path loss of the 4th terminal set First distance between end and the 4th set terminal；

Step 708, the first terminal using the first distance be less than or equal to the third distance threshold terminal as The 5th terminal set；

Step 709, the first terminal sends switching synchronisation source request to itself own base station；

Step 710, the base station receives the switching synchronisation source request that first terminal is sent；

Step 711, the base station determines that second is whole according to first distance and second distance in the 5th terminal set End；

Step 712, the base station sends the second request to the second terminal according to the identification information of the second terminal Message；

Step 713, the second terminal receives the second request message that base station is sent；

Step 714, the second terminal executes synchronisation source function.Preferably, the second terminal is according to second letter Breath executes synchronisation source function.

Embodiment eight

The embodiment of the present invention provides a kind of synchronisation source selection system, and Fig. 8 is that eight synchronisation source of the embodiment of the present invention selects system Composed structure schematic diagram, as shown in figure 8, the system includes several terminals, base station, wherein the UE in direct-connected communication makees For time synchronization source (referred to as synchronous source terminal), source terminal is synchronized using first terminal as source below, the system comprises first Terminal 810 and second terminal 820, wherein the first terminal 810 include the first transmission unit 811, the first receiving unit 812, Judging unit 813, first selecting unit 814 and the second transmission unit 815, the second terminal 820 include the 4th receiving unit 821, the 4th transmission unit 822, the 6th receiving unit 823 and execution unit 824, in which:

First transmission unit 811, for when detecting itself status information and being unsatisfactory for the first preset condition, to the One terminal set sends the first request message；

Here, the status information that the first terminal detects itself whether meet the first preset condition can there are many realize The modes of two kinds of specific implementations are provided below in mode, and first way, itself the status information includes information about power, right Whether Ying Di, the information about power that the first terminal detects itself meet preset battery condition；The second way, it is described itself Status information include signal strength, accordingly, whether the signal strength that the first terminal detects itself meets preset letter Number strength condition.

4th receiving unit 821, for receiving the first request message of first terminal transmission, wherein described first Terminal is as the synchronous source terminal in source；

Here, first request message is used to request the first information of the second terminal；

4th transmission unit 822, for sending the first response message to the first terminal, first response disappears It include the first information of itself in breath；

First receiving unit 812, the first response message sent for receiving the first terminal set, described the One response message carries the first information of the first terminal set itself；

The judging unit 813, for when the first terminal detects its own in the coverage area of base station, according to The first information judges the end for whether having in the first terminal own base station coverage area in the first terminal set End, obtains the first judging result；

The first selecting unit 814, for showing that the first terminal set does not exist when first judging result When in the first terminal own base station coverage area, the first terminal selected from second terminal set a terminal as Second terminal,

Second transmission unit 815, for sending the second request message to the second terminal, second request disappears Breath is for requesting the second terminal as new synchronization source terminal.

6th receiving unit 823 sends the second request message for receiving second transmission unit 815；

Here, second request message is for requesting the second terminal as new synchronisation source.

Preferably, second request message includes the second information needed for becoming synchronisation source；

Here, the uplink and downlink proportion of the System Frame Number in second information including direct-connected communication, time division duplex；Described Two information can also include system bandwidth information, resource pool information etc..

The execution unit 824, for executing synchronisation source function.

Preferably, for executing synchronisation source function according to second information.

Embodiment nine

Based on embodiment eight above-mentioned, the embodiment of the present invention provides a kind of synchronisation source selection system, and Fig. 9 is that the present invention is implemented Nine synchronisation source of example selects the composed structure schematic diagram of system, as shown in figure 9, the system includes several terminals, base station, wherein locating UE in direct-connected communication is whole using first terminal as source synchronisation source below as time synchronization source (referred to as synchronous source terminal) End, the system comprises first terminals 810 and second terminal 820, wherein the first terminal 810 includes the first transmission unit 811, the first receiving unit 812, judging unit 813, first selecting unit 814 and the second transmission unit 815, the second terminal 820 include the 4th receiving unit 821, the 4th transmission unit 822, the 6th receiving unit 823 and execution unit 824, wherein described 4th transmission unit 822 includes judgment module 8221, the first sending module 8222 and first processing module 8223, in which:

Whether the judgment module 8221, the status information for judging itself meet the second preset condition, obtain third Judging result；

First sending module 8222, for showing that the status information meets second in advance when the third judging result If when condition, sending first response message to the first terminal；

The first processing module 8223, for showing that the status information is unsatisfactory for second when the third judging result When preset condition, first response message is not sent to the first terminal；

Here, the 4th transmission unit 822, actually first terminal, which are integrated into, receives first asking for first terminal transmission After seeking message, first judge whether good enough the state of itself is, only when the state of itself is good enough, just eventually to first End sends the first response message.

The first terminal set judges whether itself status information meets that the second preset condition can there are many realize The modes of two kinds of specific implementations are provided below in mode, and first way, itself the status information includes information about power, right Ying Di, first sending module 8222 are as follows: the first terminal set judges whether the electricity of itself is less than preset first Power threshold obtains third judging result.The first processing module 8223 are as follows: when the third judging result shows itself When electricity is less than preset first power threshold, the first response message is not sent to the first terminal.And when the third is sentenced Break the result shows that sending the first response when the electricity of itself is more than or equal to preset first power threshold to the first terminal and disappearing Breath.

The second way, itself the status information includes signal strength, accordingly, first sending module 8222 Are as follows: whether the signal strength that the first terminal detects itself meets preset signal strength conditions, obtains third judging result. First processing module 8223 are as follows: when the third judging result shows that the signal strength of itself meets preset signal strength conditions When, the first response message is sent to the first terminal.When the third judging result shows that the signal strength of itself is unsatisfactory for When preset signal strength conditions, the terminal in the first terminal set does not send the first response to the first terminal and disappears Breath.

The first selecting unit 814, for showing that the first terminal set does not exist when first judging result When in the first terminal own base station coverage area, the first terminal selected from second terminal set a terminal as Second terminal；

6th receiving unit 823, for receiving the second request message；

The execution unit 824, for executing synchronisation source function.Preferably, for executing same according to second information Step source function.

In the embodiment of the present invention, the judgment module, for judge itself information about power and preset first electricity threshold Size relation between value obtains the second judging result；

Correspondingly, first sending module, for showing itself the information about power when second judging result When more than or equal to first power threshold, first response message is sent to the first terminal；

The first processing module, for show that itself the information about power is less than described when second judging result When the first power threshold, first response message is not sent to the first terminal.

Embodiment ten

Based on embodiment eight above-mentioned, the embodiment of the present invention provides a kind of synchronisation source selection system, and Figure 10 is that the present invention is real The composed structure schematic diagram of ten synchronisation source of example selection system is applied, as shown in Figure 10, which includes several terminals, base station, In UE in the direct-connected communication as time synchronization source (referred to as synchronization source terminal), below using first terminal as source synchronisation source Terminal, the system comprises first terminals 810 and second terminal 820, wherein the first terminal 810 includes the first transmission unit 811, the first receiving unit 812, judging unit 813, first selecting unit 814, the second transmission unit 815 and the second selecting unit 816, the first selecting unit 814 further comprises the first determining module 8141 and first choice module 8142；Described second Terminal 820 includes the 4th receiving unit 821, the 4th transmission unit 822, the 6th receiving unit 823 and execution unit 824, in which:

Second selecting unit 816, the user for information about power to be more than or equal to preset second power threshold set It is standby to be used as third terminal set；

First determining module 8141, for determining the second terminal set from the third terminal set；

The first choice module 8142, for selecting a terminal whole as second from the second terminal set End.

6th receiving unit 823, for receiving the second request message；

Embodiment 11

Based on embodiment eight above-mentioned, the embodiment of the present invention provides a kind of synchronisation source selection system, and Figure 11 is that the present invention is real The composed structure schematic diagram of 11 synchronisation source of example selection system is applied, as shown in figure 11, which includes several terminals, base station, Wherein the UE in direct-connected communication is synchronous using first terminal as source below as time synchronization source (referred to as synchronous source terminal) Source terminal, the system comprises first terminals 810 and second terminal 820, wherein the first terminal 810 includes that the first transmission is single First 811, first receiving unit 812, judging unit 813, first selecting unit 814, the second transmission unit 815 and the 4th selection are single Member 817；The second terminal 820 includes the 4th receiving unit 821, the 4th transmission unit 822, the 6th receiving unit 823 and holds Row unit 824, in which:

4th selecting unit 817, for detecting its own not in the coverage area of base station when the first terminal When, select a terminal as the second terminal from the second terminal set.

6th receiving unit 823, for receiving the second request message；

Embodiment 12

Based on embodiment eight above-mentioned, the embodiment of the present invention provides a kind of synchronisation source selection system, and Figure 12 is that the present invention is real The composed structure schematic diagram of 12 synchronisation source of example selection system is applied, as shown in figure 12, which includes several terminals, base station, Wherein the UE in direct-connected communication is synchronous using first terminal as source below as time synchronization source (referred to as synchronous source terminal) Source terminal, the system comprises first terminal 810, second terminal 820 and base station 830, wherein the first terminal 810 includes the One transmission unit 811, the first receiving unit 812, judging unit 813, first acquisition unit 818, third selecting unit 819 and Three transmission units 851；The second terminal 820 includes the 4th receiving unit 821, the 4th transmission unit 822, the 6th receiving unit 823 and execution unit 824, the base station 830 includes the 5th receiving unit 831, determination unit 832 and the 5th transmission unit 833, Wherein:

The first acquisition unit 818, for showing have in the first terminal set when first judging result When terminal in the first terminal own base station coverage area, the 4th is obtained according to the identification information of the first terminal set Terminal set；

The third selecting unit 819, for selecting the 5th terminal set from the 4th terminal set, described Five termination sets be combined into alternative synchronisation source set and for apart from the first terminal within the scope of preset third distance threshold Terminal；

The third transmission unit 851, for sending switching synchronisation source request to itself own base station, the switching is synchronized Source request includes at least the identification information of the 5th terminal set；

5th receiving unit 831, for receiving the switching synchronisation source request of first terminal transmission, the switching is synchronized Source requests to carry the identification information of the 5th terminal set, and the 5th termination set is combined into alternative synchronisation source terminal set；

The determination unit 832, for determining the in the 5th terminal set according to first distance and second distance Two terminals；

5th transmission unit 833, for being sent according to the identification information of the second terminal to the second terminal Second request message, second request message is for requesting the second terminal as new synchronisation source, it is preferable that described the Include the second information needed for becoming synchronisation source in two request messages.

6th receiving unit 823, for receiving the second request message of base station transmission；

In the embodiment of the present invention, the base station further includes the 6th transmission unit, is synchronized for sending to release to first terminal Source message, the releasing synchronisation source message is for triggering the synchronisation source function that the first terminal releases itself.

Accordingly, the first terminal further includes third receiving unit and lifting unit, in which:

The third receiving unit, for receiving the releasing synchronisation source message of itself own base station transmission；

The lifting unit, for based on the synchronisation source function of releasing synchronisation source message and release itself.

In the embodiment of the present invention, the determination unit includes third determining module and the 4th determining module, in which:

The third determining module, for calculating first distance for each of the 5th terminal set terminal With the difference of second distance, third distance is obtained；

4th determining module, for the smallest terminal of absolute value of the third distance to be determined as second terminal.

It need to be noted that: the description of following synchronisation source selection system is with the description of above-mentioned synchronisation source selection method Similar, the beneficial effect with method describes, and does not repeat them here.For undisclosed in synchronisation source of the present invention selection system embodiment Technical detail please refers to the description of synchronisation source selection method embodiment of the present invention.

In several embodiments provided herein, it should be understood that disclosed device and method can pass through it Its mode is realized.Apparatus embodiments described above are merely indicative, for example, the division of the unit, only A kind of logical function partition, there may be another division manner in actual implementation, such as: multiple units or components can combine, or It is desirably integrated into another system, or some features can be ignored or not executed.In addition, shown or discussed each composition portion Mutual coupling or direct-coupling or communication connection is divided to can be through some interfaces, the INDIRECT COUPLING of equipment or unit Or communication connection, it can be electrical, mechanical or other forms.

Above-mentioned unit as illustrated by the separation member, which can be or may not be, to be physically separated, aobvious as unit The component shown can be or may not be physical unit；Both it can be located in one place, and may be distributed over multiple network lists In member；Some or all of units can be selected to achieve the purpose of the solution of this embodiment according to the actual needs.

In addition, each functional unit in various embodiments of the present invention can be fully integrated in one processing unit, it can also To be each unit individually as a unit, can also be integrated in one unit with two or more units；It is above-mentioned Integrated unit both can take the form of hardware realization, can also realize in the form of hardware adds SFU software functional unit.

Those of ordinary skill in the art will appreciate that: realize that all or part of the steps of above method embodiment can pass through The relevant hardware of program instruction is completed, and program above-mentioned can store in computer-readable storage medium, which exists When execution, step including the steps of the foregoing method embodiments is executed；And storage medium above-mentioned includes: movable storage device, read-only deposits The various media that can store program code such as reservoir (Read Only Memory, ROM), magnetic or disk.

If alternatively, the above-mentioned integrated unit of the present invention is realized in the form of software function module and as independent product When selling or using, it also can store in a computer readable storage medium.Based on this understanding, the present invention is implemented Substantially the part that contributes to existing technology can be embodied in the form of software products the technical solution of example in other words, The computer software product is stored in a storage medium, including some instructions are used so that computer equipment (can be with It is personal computer, server or network equipment etc.) execute all or part of each embodiment the method for the present invention. And storage medium above-mentioned includes: various Jie that can store program code such as movable storage device, ROM, magnetic or disk Matter.

The above description is merely a specific embodiment, but scope of protection of the present invention is not limited thereto, any Those familiar with the art in the technical scope disclosed by the present invention, can easily think of the change or the replacement, and should all contain Lid is within protection scope of the present invention.Therefore, protection scope of the present invention should be based on the protection scope of the described claims.

Claims

1. a kind of synchronisation source selection method, which is characterized in that be applied to first terminal, the first terminal is as source synchronisation source end End, which comprises

When the status information for detecting itself is unsatisfactory for the first preset condition, first terminal sends first to first terminal set and asks Seek message；

Wherein, the first terminal collection is combined into the terminal apart from the first terminal in preset first distance threshold value, described The first information of first request message for first terminal set described in request；

The first terminal receives the first response message that the first terminal set is sent, and first response message carries The first information of the first terminal set itself；

When the first terminal detects its own in the coverage area of base station, the first terminal is according to the first information Judge the terminal for whether having in the first terminal own base station coverage area in the first terminal set, obtains first and sentence Disconnected result；

When first judging result shows the first terminal set not in the first terminal own base station coverage area When interior, the first terminal selects a terminal as second terminal from second terminal set,

Wherein, the second terminal is new synchronization source terminal, and the second terminal collection is combined into apart from the first terminal pre- If second distance threshold range in terminal.

2. the method according to claim 1, wherein the method also includes:

The first terminal sends the second request message to the second terminal, and second request message is for requesting described the Two terminals are as new synchronization source terminal.

3. being sent the method according to claim 1, wherein the first terminal receives the first terminal set The first response message, comprising:

The first terminal receives the first response message that the first terminal set is sent, wherein the first terminal set The status information of middle terminal is all satisfied the second preset condition.

4. the method according to claim 1, wherein the first information includes information about power；The method is also Include:

Information about power is more than or equal to the user equipment of preset second power threshold as third terminal collection by the first terminal It closes；

Accordingly, the first terminal selects a terminal as second terminal from second terminal set, comprising:

The first terminal determines the second terminal set from the third terminal set；

The first terminal selects a terminal as second terminal from the second terminal set.

5. method according to any one of claims 1 to 4, which is characterized in that include first terminal in the first information The identification information of set；

The method also includes:

When first judging result shows have in the first terminal set in the first terminal own base station coverage area When interior terminal, the first terminal obtains the 4th terminal set according to the identification information of the first terminal set；

4th termination set is combined into the end in the first terminal set in the first terminal own base station coverage area End；

The first terminal selects the 5th terminal set from the 4th terminal set, and the 5th termination set is combined into alternatively Synchronisation source set and be terminal apart from the first terminal within the scope of preset third distance threshold；

The first terminal sends switching synchronisation source request to itself own base station, and the switching synchronisation source request includes at least institute State the identification information of the 5th terminal set；

The first terminal receives the releasing synchronisation source message of itself own base station transmission, is based on the releasing synchronisation source message solution Except the synchronisation source function of itself.

6. described according to the method described in claim 5, it is characterized in that, the first information further includes information on path loss Information on path loss characterizes the path loss between the first terminal set and the first terminal；

Accordingly, the first terminal selects the 5th terminal set from the 4th terminal set, comprising:

The first terminal determines the first terminal and the described 4th according to the information on path loss of the 4th terminal set First distance between terminal set；

The first distance is less than or equal to the terminal of the third distance threshold as the 5th terminal by the first terminal Set.

7. method according to any one of claims 1 to 4, which is characterized in that the method also includes:

When the first terminal detects its own not in the coverage area of base station, the first terminal is from the second terminal Select a terminal as the second terminal in set.

8. a kind of synchronisation source selection method, which is characterized in that be applied to second terminal, which comprises

The second terminal receives the first request message that first terminal is sent, wherein the first terminal is as source synchronisation source Terminal, first request message are used to request the first information of the second terminal, and the first information is path loss letter Whether information, user identifier id information, the second terminal in base station range are covering model for breath, the second terminal At least one of the identification information of serving BS belonging to base station, information about power information when enclosing interior；

The second terminal sends the first response message to the first terminal, includes itself the in first response message One information；

The second terminal receives the second request message, and second request message is used to requesting the second terminal as newly Synchronisation source；

The second terminal executes synchronisation source function.

9. according to the method described in claim 8, it is characterized in that, the second terminal sends the first sound to the first terminal Answer message, comprising:

The second terminal judges whether the status information of itself meets the second preset condition, obtains third judging result；

When the third judging result shows that the status information meets the second preset condition, institute is sent to the first terminal State the first response message；

When the third judging result shows that the status information is unsatisfactory for the second preset condition, do not sent out to the first terminal Send first response message.

10. according to the method described in claim 9, it is characterized in that, the second terminal judge itself status information whether Meet the second preset condition, comprising:

The second terminal judges the size relation between the information about power and preset first power threshold of itself, obtains second Judging result；

Correspondingly, the information about power of itself described in showing when second judging result is more than or equal to first power threshold When, first response message is sent to the first terminal；

When second judging result shows that itself the information about power is less than first power threshold, not to described the One terminal sends first response message.

11. a kind of synchronisation source selection method, which is characterized in that the described method includes:

Base station receives the switching synchronisation source request that first terminal is sent, and the switching synchronisation source request carries the 5th terminal set Identification information, the 5th termination set is combined into alternative synchronisation source terminal set；

Wherein, the first distance is the distance between first terminal described in the base station distance, and the second distance is described The distance between terminal in 5th terminal set described in base station distance；

The base station sends the second request message to the second terminal according to the identification information of the second terminal, and described second Request message is for requesting the second terminal as new synchronisation source.

12. according to the method for claim 11, which is characterized in that the described method includes:

The base station is sent to first terminal releases synchronisation source message, and the releasing synchronisation source message is for triggering described first eventually End releases the synchronisation source function of itself.

13. method according to claim 11 or 12, which is characterized in that the base station is according to first distance and second distance Second terminal is determined in the 5th terminal set, comprising:

For each of the 5th terminal set terminal, the base station calculates the difference of first distance and second distance, obtains To third distance；

The smallest terminal of absolute value of the third distance is determined as second terminal by the base station.

14. a kind of first terminal, which is characterized in that the first terminal synchronizes source terminal as source, and the first terminal includes First transmission unit, the first receiving unit, judging unit and first selecting unit, in which:

First receiving unit, the first response message sent for receiving the first terminal set, first response Message carries the first information of the first terminal set itself；

The judging unit, for when the first terminal detects its own in the coverage area of base station, according to described One information judges the terminal for whether having in the first terminal own base station coverage area in the first terminal set, obtains First judging result；

The first selecting unit, for showing the first terminal set not described first when first judging result When in terminal own base station coverage area, the first terminal selects a terminal whole as second from second terminal set End,

15. first terminal according to claim 14, which is characterized in that the first terminal further includes the second transmission list Member, for sending the second request message to the second terminal, second request message is for requesting the second terminal to be made For new synchronization source terminal.

16. first terminal according to claim 14, which is characterized in that first receiving unit, it is described for receiving The first response message that first terminal set is sent, wherein the status information of terminal is all satisfied the in the first terminal set Two preset conditions.

17. first terminal according to claim 14, which is characterized in that the first information includes information about power；It is described First terminal further includes the second selecting unit, for information about power to be more than or equal to the user equipment of preset second power threshold As third terminal set；

Accordingly, the first selecting unit includes the first determining module and first choice module, in which:

First determining module, for determining the second terminal set from the third terminal set；

The first choice module, for selecting a terminal as second terminal from the second terminal set.

18. 4 to 17 described in any item first terminals according to claim 1, which is characterized in that comprising the in the first information The identification information of one terminal set；

The first terminal further includes first acquisition unit, third selecting unit, third transmission unit, the reconciliation of third receiving unit Except unit, in which:

The first acquisition unit, for showing have in the first terminal set described first when first judging result When terminal in terminal own base station coverage area, the 4th termination set is obtained according to the identification information of the first terminal set It closes；

The third selecting unit, for selecting the 5th terminal set, the 5th terminal from the 4th terminal set Collection is combined into alternative synchronisation source set and is the terminal apart from the first terminal within the scope of preset third distance threshold；

The third transmission unit, for sending switching synchronisation source request, the switching synchronisation source request to itself own base station Including at least the identification information of the 5th terminal set；

19. first terminal according to claim 18, which is characterized in that the first information further includes path loss letter Breath, the information on path loss characterize the path loss between the first terminal set and the first terminal；

Accordingly, the third selecting unit includes the second determining module and the second selecting module, in which:

Second determining module determines the first terminal for the information on path loss according to the 4th terminal set With the first distance between the 4th terminal set；

Second selecting module, for the first distance to be less than or equal to the terminal of the third distance threshold as described in 5th terminal set.

20. 4 to 17 described in any item first terminals according to claim 1, which is characterized in that the first terminal further includes Four selecting units, for when the first terminal detects its own not in the coverage area of base station, from the second terminal Select a terminal as the second terminal in set.

21. a kind of second terminal, which is characterized in that the second terminal includes the 4th receiving unit, the 4th transmission unit, the 6th Receiving unit and execution unit, in which:

4th receiving unit, for receiving the first request message of first terminal transmission, wherein the first terminal conduct Source synchronizes source terminal, and first request message is used to request the first information of the second terminal, and the first information is road Diameter lose information, the second terminal whether information, user identifier id information, the second terminal in base station range At least one of the identification information of serving BS belonging to base station, information about power information when in coverage area；

4th transmission unit wraps in first response message for sending the first response message to the first terminal Include the first information of itself；

6th receiving unit, for receiving the second request message, second request message is for requesting second end End is as new synchronisation source；

The execution unit, for executing synchronisation source function.

22. second terminal according to claim 21, which is characterized in that the 4th transmission unit include judgment module, First sending module and first processing module, in which:

Whether the judgment module, the status information for judging itself meet the second preset condition, obtain third judging result；

First sending module, for showing that the status information meets the second preset condition when the third judging result When, first response message is sent to the first terminal；

The first processing module, for showing that the status information is unsatisfactory for the second preset condition when the third judging result When, first response message is not sent to the first terminal.

23. second terminal according to claim 22, which is characterized in that the judgment module, for judging itself electricity The size relation between information and preset first power threshold is measured, the second judging result is obtained；

Correspondingly, first sending module, for showing that itself the information about power is greater than when second judging result When equal to first power threshold, first response message is sent to the first terminal；

The first processing module, for showing that itself the information about power is less than described first when second judging result When power threshold, first response message is not sent to the first terminal.

24. a kind of base station, which is characterized in that the base station includes the 5th receiving unit, determination unit and the 5th transmission unit, In:

5th receiving unit, for receiving the switching synchronisation source request of first terminal transmission, the switching synchronisation source request The identification information of the 5th terminal set is carried, the 5th termination set is combined into alternative synchronisation source terminal set；

The determination unit, for determining second terminal in the 5th terminal set according to first distance and second distance；

5th transmission unit, for sending the second request to the second terminal according to the identification information of the second terminal Message, second request message is for requesting the second terminal as new synchronisation source.

25. base station according to claim 24, which is characterized in that the base station includes the 6th transmission unit, for the One terminal, which is sent, releases synchronisation source message, and the releasing synchronisation source message is for triggering the synchronization that the first terminal releases itself Source function.

26. base station according to claim 24, which is characterized in that the determination unit includes third determining module and the 4th Determining module, in which:

The third determining module, for for each of the 5th terminal set terminal, calculating first distance and the Two, apart from its difference, obtain third distance；

27. a kind of synchronisation source selects system, which is characterized in that the system comprises first terminals and second terminal, wherein described First terminal includes the first transmission unit, the first receiving unit, judging unit, first selecting unit and the 4th selecting unit, institute Stating second terminal includes the 4th receiving unit and the 4th transmission unit, in which:

4th receiving unit, for receiving the first request message of first terminal transmission, wherein the first terminal conduct Source synchronizes source terminal, and first request message is used to request the first information of the second terminal；

The first selecting unit, for showing the first terminal set not described first when first judging result When in terminal own base station coverage area, select a terminal as second terminal from second terminal set；

4th selecting unit, for when the first terminal detects its own not in the coverage area of base station, from Select a terminal as second terminal in two terminal set；

28. system according to claim 27, which is characterized in that include the mark of first terminal set in the first information Know information；The first terminal further includes first acquisition unit, third selecting unit and third transmission unit；Accordingly, described System further includes base station, and the base station includes the 5th receiving unit, determination unit and the 5th transmission unit, in which:

5th receiving unit, for receiving the switching synchronisation source request of first terminal transmission, the 5th termination set is combined into Alternative synchronisation source terminal set；