CN103686908B

CN103686908B - Direct-connected communicating terminal conversation switching method and device in a kind of mobile communications network

Info

Publication number: CN103686908B
Application number: CN201210351791.3A
Authority: CN
Inventors: 谢宝国; 李志军
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2012-09-20
Filing date: 2012-09-20
Publication date: 2018-10-26
Anticipated expiration: 2032-09-20
Also published as: WO2014044211A1; CN103686908A

Abstract

The invention discloses direct-connected communicating terminal conversation switching method and devices in a kind of mobile communications network, during first D2D terminals conversate with the 2nd D2D terminals, when D2D regional extents change, network side initiates the switching that D2D carryings are carried with EPS according to D2D session switching request decisions.Using the present invention, realize in EPS networks D2D carrying and EPS carry between seamless switching, so that user by broken words are generated because of terminal movement or voice is undesirable influences, is not improved user experience.

Description

Direct-connected communicating terminal conversation switching method and device in a kind of mobile communications network

Technical field

The present invention relates to direct-connected communicating terminal sessions in mobile communication technology field more particularly to a kind of mobile communications network Switching method and device.

Background technology

In mobile communication, communication can be happened at user equipment (User Equipment, abbreviation UE) (or also referred to as eventually End or user terminal) between application server (Application Server, referred to as AS), two can also be happened at Between user equipment.Communication between two user equipmenies may pass through AS transfers, it is also possible to lead between two user equipmenies It is carried out after IP traffic end to end.

In mobile communications, (Packet Service, abbreviation PS) network and evolved packet system (Evolved are grouped Packet System, referred to as EPS) provide the communication of IP-based data.The IP address of UE is by the IP allocation entities in network It is responsible for, all IP traffics are required to by the IP allocation entities.

Fig. 1 be according to UE access under the relevant technologies to 3GPP (3rd Generation Partnership Project, Third generation partnership project) wireless network packet domain configuration diagram.As shown in Figure 1, the framework is related to：The land UE, UMTS Wireless access network (UMTS Terrestrial Radio Access Network, referred to as UTRAN), the land of evolution is wireless Access net (Evolved UMTS, referred to as E-UTRAN), Serving GPRS Support Node (Serving GPRS Supporting Node, referred to as SGSN), mobility management entity (Mobile Management Entity, abbreviation MME), homing position post Storage (Home Location Register, referred to as HLR)/home subscriber server (Home Subscriber Server, Referred to as HSS), gateway (Serving Gateway, abbreviation SGW), grouped data network gateway (Packet Data Network Gateway, referred to as PGW), Gateway GPRS Support Node (Gateway GPRS Supporting Node, referred to as For GGSN), AS.Wherein, PGW, GGSN be respectively E-UTRAN, UTRAN/GERAN under IP allocation entities, can by GGSN, PGW is referred to as public data network gateway.

UE can be linked into core net by UMTS, E-UTRAN, after being assigned IP address, could realize and application server AS, other-end carry out IP data communications.In communication process, IP traffic is forwarded to public data network behind base station Gateway (GGSN/PGW) is sent to AS, destination UE then again by GGSN/PGW according to IP routing rules.Wherein, UE is to base It stands, base station to the communication between public data network gateway (GGSN/PGW), is not based on IP routing rules, but based on special With data tunnel route technology.In the whole process, base station does not perceive IP layers of information, for example, base station does not know the IP of UE The information such as address, port.

With smart mobile phone extensive use, transmission media data flow is more and more frequent in a mobile network.Especially prominent It is, as social networking application and location-based communication applications become more and more popular, (under the same base station, to face in the same region In nearly base station range) data traffic it is increasing.These flows are required to travel back across the public data network gateway of core net (GGSN/PGW), thus return bandwidth requirement is considerably increased, increases the time delay of IP communications, also increases base station (E- UTRAN) and the load of public data network gateway (GGSN/PGW) is born.Also, as mobile broadbandization is more and more deep, day The IP traffic amount that benefit increases also carries the public data network gateway (GGSN/PGW) of wireless base station (E-UTAN) and core net Higher requirement is gone out.

For increasing problems of liquid flow, it would be desirable to be able to necessary shunting is carried out to specific IP flows, to mitigate to public affairs The load of data gateway (GGSN/PGW) and the signaling impact to core net altogether.Existing scheme may be used what base station was shunted Mode, the IP data that UE accesses the websites IT directly can be linked into external data gateway by base station.

With the explosive growth of smart mobile phone, network cannot be satisfied IP flow increased requirements gradually, therefore, how solve The impact that certainly growing IP flows carry out Netowrk tape is current problem to be solved.Industry currently discuss terminal it Between in such a way that LTE radio bands directly establish communication (LTEDirect communications), i.e., the terminal geographically closed on (such as：Within the scope of 1Km), establish point-to-point direct-connected wireless telecommunications using operator's LTE frequency spectrum resources.The direct-connected communication of terminal room It is a kind of emerging wireless communication mode, realizes that the terminal of direct-connected communication is also a kind of novel D2D (Direct to Direct Communication, direct-connected communication) terminal, this just needs 3GPP network supports to be linked into network to the D2D terminals, to the D2D Mobile management, D2D certifications and Internet resources distribution that terminal is enhanced etc., and need the new access for defining adjacent terminal end Control method and system ensure to realize that the IP of direct-connected data link is communicated under network-control between adjacent terminal end.

Consider the traffic load of mitigation network side, it is desirable to be able to realize that the terminal in close region uses LTE radio bands Direct communication is carried out, IP traffic is without base station and core net loopback, to mitigate the traffic load of network side.Fig. 2 is D2D logical One of scene of letter seeks the scheme for establishing direct-connected communication link that is, between UE1 and UE2, is that D2D terminals are directly led to Letter.The communication uses the burst technology for increasing power by tune, and similar WIFI broadcast mechanisms to realize and mutually find, then The direct data communication of D2D terminal rooms is established under network-control, the transmitting-receiving of IP data packets is without base station and core net.But D2D sessions have regional location scope limitation, therefore when the demand for having D2D carryings to switch mutually with EPS carryings at critical zone.

In the prior art, using EPS frameworks, source UE1 and opposite end UE2 conversates in the same eNB, works as source The switching that conversates is needed when UE1 is moved to another eNB, shown in Figure 3, session switching flow at this time is as follows：

Step 101, source UE1 and opposite end UE2 is conversated in EPS real-time performances by EPS carryings, source and opposite end All in the first eNB Radio Access Networks.

Step 102, when source is moved to two eNB from the first eNB, the first eNB by the measurement report of source UE1, It was found that source has been moved to the 2nd eNB, the first eNB just sends session switching request from X2 interface to the 2nd eNB.

After 2nd eNB receives session switching request, wireless data carrying is established with source UE1, and session request is issued MME。

Step 103, if the X2 interface of step 102 is not used to switch, and by the way of the switching of S1 interfaces, the first eNB is needed Session switching request is issued into MME by S1 interfaces.

MME is conversated switching by the 2nd eNB, and the 2nd eNB and source UE1 establishes wireless data carrying.

Step 104~105, MME carries out bearing modification by SGW/PGW；SGW obtains second in bearing modification message The IP address and Tunnel Identifier of eNB, it is established that the tunneling data channel with the 2nd eNB.

Step 106, the session of source and opposite end switches successfully, and source UE1 can send IP bag datas extremely by the 2nd eNB The opposite end UE2 of first eNB, source conversate with opposite end on EPS links.

When D2D sessions occur, if movement has occurred in source or opposite end, D2D regional extents are had left, it at this time may be because of nothing Line signal is bad, it may occur that D2D sessions broken string or session result are very poor.There is D2D to carry the switching demand carried to EPS； Vice versa.Mutual switching is carried with EPS for session D2D carryings, is very different with existing session handoff technique, D2D When session needs switching, possible source is still located at same eNB with opposite end, therefore eNB can not be according to the letter in measurement report Number power switches over.In addition, in handoff procedure, network side also needs to know source and the information of opposite end, again for terminal D2D carryings or EPS carryings are established, session switching could be completed.Therefore, for D2D sessions, when terminal is moved in EPS networks When dynamic, the seamless switching of D2D carryings and EPS carryings how is solved, D2D sessions is made broken words will not to occur because of the movement of terminal Or session result is very poor, reduce user experience, be in the prior art urgent need to resolve the problem of.

Invention content

The technical problem to be solved by the present invention is to provide direct-connected communicating terminal conversation switching methods in a kind of mobile communications network And device, it realizes the seamless switching between D2D carryings and EPS carryings in EPS networks, user is made not produced by because of terminal movement Raw broken words or the undesirable influence of voice, improve user experience.

In order to solve the above technical problems, the present invention provides direct-connected communicating terminal session switchings in a kind of mobile communications network Method,

During first direct-connected communication (D2D) terminal conversates with the 2nd D2D terminals, when D2D regional extents become When change, network side initiates the switching that D2D carryings are carried with evolved packet system (EPS) according to D2D session switching request decisions.

Further, the D2D regional extents change, including：

First D2D terminals and the into or out regions D2D of the 2nd D2D terminals.

Further, when the first D2D terminals enter the regions D2D with the 2nd D2D terminals, network side decision initiates EPS carryings The switching carried to D2D；

When first D2D terminals leave the regions D2D with the 2nd D2D terminals, network side decision initiates D2D and is carried to EPS carryings Switching.

Further, the first D2D terminals or the 2nd D2D terminals are sentenced by the power of inspection other side's wireless signal Break when D2D regional extents and changing, the D2D sessions switching request is initiated to network side；

Alternatively, the base station of network side or mobility management entity (MME) according in measurement report location information or When the D2D discovery mechanisms of wireless access side or the D2D discovery mechanisms of core-network side judge that D2D regional extents change, Initiate the D2D sessions switching request；

Wherein, the terminal of the first D2D terminals and the 2nd D2D terminals is included in the D2D sessions switching request Mark, D2D sessions switching instruction.

Further, the method further includes：

The network side is according to the D2D sessions switching request, to the first D2D terminals and the 2nd D2D terminals After carrying out D2D communication checks, decision initiates the switching of the D2D carryings and EPS carryings.

Further, the D2D communication checks, including following one or its arbitrary combination：The first D2D terminals and institute State D2D regional locations, the D2D abilities of the 2nd D2D terminals；The D2D abilities of network side；The first D2D terminals and described second Whether D2D terminals contract D2D business.

Further, the method further includes：

Network side decision initiates D2D carrying and after the switching of EPS carryings, is the first D2D terminals and described the Two D2D terminal distribution D2D bearing resources or EPS bearing resources.

Further, the method further includes：

When the first D2D terminals or the 2nd D2D terminals are in idle condition, network side is according to the terminal Mark is paged, and the first D2D terminals or the 2nd D2D terminals is made to restore connected state.

The present invention also provides direct-connected communicating terminal session switching devices in a kind of mobile communications network, and it is whole to be applied to D2D End, described device include：

D2D regional extent detection modules, the regions the D2D model for detecting D2D terminals and the opposite ends D2D currently to conversate It encloses and whether changes；

Session switches initiation module, is cut for when D2D regional extents change, initiating the D2D sessions to network side Change request；

Session switching executing module switches for receiving the session switching command from network side, and according to the session Order carries out corresponding session handover operation.

Further, the session switching initiation module is used for, this is carried in the D2D sessions switching request of initiation The terminal iidentification and D2D session switching requests of D2D terminals and the opposite ends D2D indicate.

Further, the D2D regional extents detection module is used for, and by checking the power of other side's wireless signal, is judged Whether D2D regional extents change；

Wherein, the D2D regional extents change, including：Enter or leave the regions D2D with the opposite ends D2D.

Further, described device further includes：

Communication link establishes module, is held for establishing D2D carryings between the opposite ends D2D or establishing EPS with network side It carries.

The present invention also provides direct-connected communicating terminal session switching devices in a kind of mobile communications network, are applied to network Side, described device include：

Session hand-off process module, for when the regions the D2D model for knowing the D2D terminals to conversate and the opposite ends D2D It encloses when changing or according to D2D session switching requests, decision initiates the switching of D2D carryings and EPS carryings.

Further, the session hand-off process module is used for, and knows D2D terminals and the opposite ends D2D in the following manner Whether D2D regional extents change：

According to the D2D discovery mechanisms of location information or wireless access side in measurement report or core-network side D2D discovery mechanisms.

Further, the session hand-off process module is used for, after decision initiates the switching that D2D carryings are carried with EPS, Terminal iidentification and the D2D sessions switching instruction of the D2D terminals and the opposite ends D2D are carried in session handover request, and to described D2D terminals send session switching command with the opposite ends D2D.

Further, described device further includes：

Communication service resource distribution module, for distributing D2D communication service resources, packet for the D2D terminals and the opposite ends D2D Include D2D bearing resources or EPS bearing resources.

Further, described device further includes：

D2D communication services check module, for check requested D2D sessions switching whether meet one of following condition or It is arbitrarily combined：The D2D regional locations of the D2D terminals and the opposite ends D2D, D2D abilities；The D2D abilities of network side；The D2D Whether terminal and the opposite ends D2D contract D2D business.

Further, described device further includes：

Module is paged, for when the D2D terminals and the opposite ends D2D are in idle condition, according in session switching request The D2D terminals and the opposite ends D2D terminal iidentification, carrying out paging to the D2D terminals and the opposite ends D2D makes its restore to connect State.

In conclusion using the present invention, carried out in D2D sessions between the terminal with direct-connected communication, when terminal occurs When moving and leaving or entering D2D conversation regions, the seamless switching of D2D carryings and EPS carryings is realized.

Compared with prior art, the present invention at least has the advantages that：In D2D communications, controllable in network Under the premise of realize D2D sessions and session switching, so that D2D sessions is not occurred because of terminal mobile and is broken or voice is bad, make The experience of user is not influenced by terminal movement；The data traffic for also effectively reducing network simultaneously, makes Internet resources optimize, User also obtains the more preferably preferably application experience such as telecommunication service quality, low rate.

Description of the drawings

Attached drawing described herein is used to provide further understanding of the present invention, and is constituted part of this application, this hair Bright illustrative embodiments and their description are not constituted improper limitations of the present invention for explaining the present invention.In the accompanying drawings：

Fig. 1 is the configuration diagram according to UE access under the relevant technologies to packet domain；

Fig. 2 is to use packet domain framework, and D2D terminals realize the configuration diagram of the direct-connected communications of D2D；

Fig. 3 is that terminal conversates the flow diagram of switching in EPS networks in the prior art；

Fig. 4 is that D2D terminals realize that the flow of D2D sessions switching is shown with opposite end at same eNB in the embodiment of the present invention one It is intended to；

Fig. 5 is that D2D terminals realize that the flow of D2D sessions switching is shown with opposite end at same eNB in the embodiment of the present invention two It is intended to；

Fig. 6 is that D2D terminals realize that the flow of D2D sessions switching is shown with opposite end at same eNB in the embodiment of the present invention three It is intended to；

Fig. 7 is that D2D terminals realize that the flow of D2D sessions switching is shown with opposite end under adjacent eNB in the embodiment of the present invention four It is intended to；

Fig. 8 is that D2D terminals realize that the flow of D2D sessions switching is shown with opposite end under adjacent eNB in the embodiment of the present invention five It is intended to；

Fig. 9 is D2D terminal session switching devices in the network side and the end sides D2D mobile communications network of the embodiment of the present invention Schematic block diagram.

Specific implementation mode

Present embodiment provides a kind of method that D2D terminal sessions switch in mobile communications network, it is intended that D2D sources and the opposite ends D2D are carried using D2D or during EPS carryings conversate, and when movement has occurred in terminal, are left or entered When D2D regional extents, to ensure that user experience is unaffected, 3GPP networks need to provide seamless session switching service, use The quality of the conversation at family is not influenced by terminal movement.

The method that D2D terminal sessions switch in the mobile communications network that present embodiment provides, using following scheme：

During first D2D terminals conversate with the 2nd D2D terminals, when D2D regional extents change, network side The switching of D2D carryings and EPS carryings is initiated according to D2D session switching request decisions.

Further, the D2D regional extents change, including：

First D2D terminals enter with the 2nd D2D terminals or leave the regions D2D.

Further,

When first D2D terminals enter the regions D2D with the 2nd D2D terminals, network side decision initiates EPS and is carried to D2D carryings Switching；

Further, the first/second D2D terminals or network side eNB, MME are one of arbitrary can be according to itself Ability judges whether D2D regional extents change.

Further, when network side judges that D2D regional extents change, the D2D sessions switching request is initiated, and Decision initiates the switching of D2D carryings and EPS carryings.

Further, when the first/second D2D terminals judge that D2D regional extents change, to network side eNB/ MME initiates the D2D sessions switching request；

Terminal iidentification comprising opposite end, D2D sessions switching instruction in the D2D sessions switching request.

Further, after network side switches instruction progress D2D communication checks according to the D2D sessions, decision is initiated D2D and is held Carry the switching with EPS carryings.

The D2D communication checks include：Check whether first/second D2D terminals have D2D professional abilities, Yi Ji The position detection of one/the 2nd whether into or out D2D regional extents of D2D terminals, etc..

More specifically, said program includes following main contents：

D2D sessions are carried out when the D2D sources and opposite end that are accessed in same eNB or adjacent eNB are carried by D2D, this Movement has occurred in Shi Yuanduan or opposite end, has left the regions D2D.If terminal has the ability to check whether D2D regional extents become Change, just D2D session switching requests are initiated to network side when D2D terminals find that the regions D2D are critical, request is carried from D2D to be switched It is carried to EPS, prevents from leading to D2D conversations because distance is excessive between terminal.It needs to carry other side in D2D session switching requests Terminal iidentification, notice network side be to conversate with which terminal.It also needs to carry D2D meetings in D2D session switching requests Words switching instruction, is shown to be the switching of a D2D session；For network side, the inspection if Radio Access Network eNB has the ability It looks into whether D2D regional extents change, D2D session switching requests can be initiated to MME when eNB has found that the regions D2D are critical, It is also required to carry source mark, opposite end mark and D2D sessions switching instruction in D2D session switching requests.Equally, if mobility Managed network element MME has the ability to check whether D2D regional extents change, and when MME has found that the regions D2D are critical, also decision is initiated Then D2D session switching requests notify Radio Access Network eNB to conversate switching.MME receives session switching request or decision When initiating a session request, MME switches instruction progress D2D communication checks according to D2D sessions and decision is initiated to be carried to EPS from D2D The session of carrying switches.D2D communication checks include checking whether terminal and network have D2D professional abilities and terminal Into or leave the position detection of D2D regional extents.If D2D sources or opposite end are in IDLE state, network side needs elder generation Paging (paging) terminal makes terminal be linked into network and establishes EPS carryings, and terminal is made to restore connected state.Network side executes D2D Session switches, and is that resource is distributed in D2D sources and the opposite ends D2D, and notifies according to the terminal and source mark in session switching request D2D sources and opposite end execute session switching.IP sessions packet is switched to by source and opposite end from D2D carryings to carry out from EPS carryings Transmitting-receiving, and optionally release D2D carryings, complete D2D and carry the session handover operation carried to EPS.

When the D2D sources and opposite end of same eNB or adjacent eNB access carry out D2D sessions by EPS, at this time Movement has occurred in source or opposite end, enters D2D regional extents.To make core network data effectively shunt and being provided for terminal communication Higher QoS, lower rate communication service, need the switching that conversates.If terminal has the ability to check whether D2D regional extents are sent out Changing, just D2D session switching requests are initiated when D2D terminals find that the regions D2D are critical to network side, and request is carried from EPS D2D carryings are switched to, make to conversate using the D2D carryings of higher speech quality between terminal.It is needed in D2D session switching requests The terminal iidentification of other side is carried, notice network side is being conversated with which terminal.It is also needed in D2D session switching requests D2D sessions switching instruction is carried, the switching of a D2D session is shown to be；For network side, if Radio Access Network ENB has the ability to check whether D2D regional extents change, and D2D meetings can be initiated to MME when eNB has found that the regions D2D are critical Switching request is talked about, is also required to carry source mark, opposite end mark and D2D sessions switching instruction in D2D session switching requests.Together Sample, if mobile management network element MME has the ability to check whether D2D regional extents change, when MME has found that the regions D2D are faced Also decision initiates D2D session switching requests when boundary, then Radio Access Network eNB is notified to conversate switching.MME receives session When switching request or decision initiate a session request, MME switches instruction according to D2D sessions and carries out D2D communication checks and decision initiation It is carried to the session switching that EPS is carried from D2D.D2D communication checks include checking whether terminal and network have D2D business energy Whether power and terminal enter or leave the position detection of D2D regional extents.Network side executes D2D sessions switching, according to session Terminal in switching request and source mark are that resource is distributed in D2D sources and the opposite ends D2D, and D2D sources and opposite end is notified to execute Session switches.IP sessions packet is switched to by source and opposite end from EPS carryings to be received and dispatched from D2D carryings, and is optionally discharged EPS is carried, and is completed EPS and is carried the session handover operation carried to D2D.

Using the above scheme, 3GPP networks can carry out D2D communication service inspections to the service request that D2D terminals are initiated, and Decide whether the communication resource for terminal distribution D2D sessions according to the result of D2D communication service inspections, and realizes that D2D sessions are cut It changes.It conversates switching if network side decision is D2D terminals, the communication resource of D2D sessions, end is provided for this session switching The switching of D2D carryings and EPS carryings is completed between end according to the communication resource that network side provides.

For the ease of illustrating the present invention, the implementation of technical solution of the present invention is made below with reference to drawings and the specific embodiments It is described in further detail.It should be noted that in the absence of conflict, the features in the embodiments and the embodiments of the present application It mutually can arbitrarily combine.

Embodiment one

The present embodiment mainly describes the D2D sources accessed in same eNB and opposite end and carries progress D2D meetings by D2D Words, movement has occurred in source at this time, has left the regions D2D.Whether D2D sessions are met for terminal detection D2D regional extents Scene, D2D terminals check can initiate D2D session switching requests when the regions D2D are critical to network side.Network side eNB is examined The scene whether D2D regional extents meet D2D sessions is surveyed, eNB checks that can initiate D2D sessions to MME when the regions D2D are critical cuts Change request；The no scene for meeting D2D sessions of D2D regional extents is checked for network side MME, MME is checked can when the regions D2D are critical D2D sessions switching whether is initiated with decision, then Radio Access Network eNB is notified to conversate switching.MME is according to D2D sessions Switching instruction carries out D2D communication checks and decision is initiated to be carried to the session switching that EPS is carried from D2D.If terminal and opposite end EPS bearer connections are always maintained at, and network side notifies terminal to execute session switching, source and opposite end and carry IP sessions packet from EPS On received and dispatched, and discharge D2D carrying, complete D2D carry the session handover operation carried to EPS.

Shown in Figure 4, the present embodiment specific steps are described as follows：

Step 201：D2D sources and the opposite ends D2D are all linked into EPS networks by same eNB, and network side is source and terminal Establish EPS carryings and D2D carryings.D2D sources and terminal carry out D2D sessions using D2D links.

Step 202：D2D sources are moved, and D2D regional extents are gradually left.At this time be prevent conversation, need into Guild's words switching.

If D2D terminals self-check D2D regional extents whether meet, such as can check other side wireless signal it is strong Weak, when finding that D2D regional extents are critical, D2D terminals can initiate session switching request to network side, and request is switched to EPS and holds It carries.

Source mark, the information such as opposite end mark and D2D sessions switching instruction are carried in session switching request.

Step 203：After network side eNB receives the D2D session switching requests of terminal initiation, by the S1 interfaces with MME, to MME sends session switching request.

If network side eNB has the ability to check whether D2D regional extents meet according to relevant information, such as according to terminal Location information in measurement report, or the D2D discovery mechanisms according to wireless access side.When eNB has found that D2D regional extents are critical When, eNB can initiate session switching request to MME, and request is switched to EPS carryings.

Step 204：After MME receives session switching request, indicated according to the D2D session switching requests in switching request, it is right Source and terminal carry out D2D communication checks, check whether with D2D abilities and D2D business of having contracted.And to source and terminal D2D regional extents checked, if the position of terminal met D2D sessions switching condition.Meet if checked It is required that MME just carries out D2D session handover operations.

Step 205：ENB where from MME to terminal sends session switching command, and notice eNB conversates switching.

If terminal or eNB do not send session switching request to MME, network side MME has the ability according to relevant information inspection Whether the D2D regional extents of terminal have met session switching condition, such as the D2D discovery mechanisms of core-network side.When MME has found When D2D regional extents are critical, MME can decision initiation session handover operation.MME can send session to the eNB where terminal at this time Switching request.

Source mark, the information such as opposite end mark and D2D sessions switching instruction are carried in session switching request or order.

Step 206：ENB check source whether have been established wireless data carrying, if having been established wireless data carrying, eNB to Source sends session switching command, and notice source conversates switching, and being switched to EPS from D2D carryings carries.Session switching command Middle carrying opposite end mark, D2D are carried to information such as the instructions of EPS carrying switchings.

Step 207：While source carries transmission IP data packets by D2D again, forwarding IP data packets also are carried to EPS, It is interrupted as D2D is carried, opposite end can also receive the IP data packets of source by EPS carryings at this time.

Step 208~209：Source returns to session switching to eNB and confirms response, and eNB confirms to MME return session switchings to be rung It answers.Source mark, the IP address and tunnel id information of the eNB distributed for source can be carried in the confirmation response that eNB is returned.

Step 210：After MME receives session switching confirmation response, optionally, bearing modification request can be initiated to SGW/PGW, Restore the downlink bearing link of source EPS carryings.

Step 211：After EPS carries uplink downlink recovery, the IP data packets of source can be carried by EPS receives and dispatches, no It is needing to carry by D2D.

Step 212：ENB where from MME to opposite end sends session switching command or request, and notice eNB conversates switching.

Step 213：ENB check opposite end whether have been established wireless data carrying, if having been established wireless data carrying, eNB to Opposite end sends session switching command, and notice opposite end conversates switching, and being switched to EPS from D2D carryings carries.Session switching command Middle carrying source mark, D2D are carried to information such as the instructions of EPS carrying switchings.

Step 214：While opposite end carries transmission IP data packets by D2D again, forwarding IP data packets also are carried to EPS, It is interrupted as D2D is carried, source can also receive the IP data packets of opposite end by EPS carryings at this time.

Step 215~216：Opposite end returns to session switching to eNB and confirms response, and eNB confirms to MME return session switchings to be rung It answers.Opposite end mark, the IP address and tunnel id information of the eNB distributed for opposite end can be carried in the confirmation response that eNB is returned.

Step 217：After MME receives session switching confirmation response, optionally, bearing modification request can be initiated to SGW/PGW, Restore the downlink bearing link of opposite end EPS carryings.

Step 218：After EPS carries uplink downlink recovery, the IP data packets of source can be carried by EPS receives and dispatches, no It is needing to carry by D2D.

Step 219：After D2D carryings are switched to EPS carryings, optionally, source and opposite end ask release D2D wireless to eNB Resource, notice source and opposite end discharge D2D radio resources after eNB decisions.

Embodiment two

The present embodiment mainly describes the D2D sources accessed in same eNB and opposite end and carries progress D2D meetings by D2D Words, movement has occurred in source at this time, has left the regions D2D.Whether D2D sessions are met for terminal detection D2D regional extents Scene, D2D terminals check can initiate D2D session switching requests when the regions D2D are critical to network side.Network side eNB is examined The scene whether D2D regional extents meet D2D sessions is surveyed, eNB checks that can initiate D2D sessions to MME when the regions D2D are critical cuts Change request；The no scene for meeting D2D sessions of D2D regional extents is checked for network side MME, MME is checked can when the regions D2D are critical D2D sessions switching whether is initiated with decision, then Radio Access Network eNB is notified to conversate switching.MME is according to D2D sessions Switching instruction carries out D2D communication checks and decision is initiated to be carried to the session switching that EPS is carried from D2D.If at terminal and opposite end In idle states, EPS bearer connections are interrupted, network elder generation call terminal, so that terminal is linked into network and are established EPS carryings.Network side is logical Know that terminal executes session switching, source and opposite end and receives and dispatches IP sessions packet from EPS carryings, and discharge D2D carryings, completes D2D carries the session handover operation carried to EPS.

Shown in Figure 5, the present embodiment specific steps are described as follows：

Step 301：D2D sources and the opposite ends D2D are all linked into EPS networks by same eNB, and network side is source and terminal D2D carryings are established, source and opposite end are in IDLE state, the release of EPS carryings at this time.D2D sources and terminal use D2D links Carry out D2D sessions.

Step 302：D2D sources are moved, and D2D regional extents are gradually left.At this time be prevent conversation, need into Guild's words switching.

Step 303：After network side eNB receives the D2D session switching requests of terminal initiation, by the S1 interfaces with MME, to MME sends session switching request.

Step 304：After MME receives session switching request, indicated according to the D2D session switching requests in switching request, it is right Source and terminal carry out D2D communication checks, check whether with D2D abilities and D2D business of having contracted.And to source and terminal D2D regional extents checked, if the position of terminal met D2D sessions switching condition.Meet if checked It is required that MME just carries out D2D session handover operations.

Step 305：ENB where from MME to terminal sends session switching command, and notice eNB conversates switching.

Step 306：If source is in idle states, EPS carryings are not set up, network side pages source, and activation is eventually It terminates into network and establishes EPS carryings.

Step 307：After source receives paging, access request is sent to eNB, request is linked into network again, and eNB will be accessed MME is issued in request, and MME notices eNB is that source establishes wireless data carrying.MME sends carrying to SGW/PGW and establishes request, Core-network side establishes EPC carryings, finally sets up EPS carryings.

Step 308：ENB check source whether have been established wireless data carrying, if having been established wireless data carrying, eNB to Source sends session switching command, and notice source conversates switching, and being switched to EPS from D2D carryings carries.Session switching command Middle carrying opposite end mark, D2D are carried to information such as the instructions of EPS carrying switchings.

Step 309：While source carries transmission IP data packets by D2D again, forwarding IP data packets also are carried to EPS, It is interrupted as D2D is carried, opposite end can also receive the IP data packets of source by EPS carryings at this time.

Step 310~311：Source returns to session switching to eNB and confirms response, and eNB confirms to MME return session switchings to be rung It answers.Source mark, the IP address and tunnel id information of the eNB distributed for source can be carried in the confirmation response that eNB is returned.

Step 312：After MME receives session switching confirmation response, optionally, bearing modification request can be initiated to SGW/PGW, Change the downlink bearing link of source EPS carryings.

Step 313：After EPS carrying uplink downlinks are normal, the IP data packets of source can be carried by EPS receives and dispatches, no It is needing to carry by D2D.

Step 314：ENB where from MME to opposite end sends session switching command or request, and notice eNB conversates switching.

Step 315：If opposite end is in idle states, EPS carryings are not set up, network side pages opposite end, and activation is eventually It terminates into network and establishes EPS carryings.

Step 316：After opposite end receives paging, access request is sent to eNB, request is linked into network again, and eNB will be accessed MME is issued in request, and MME notices eNB is that wireless data carrying is established in opposite end.MME sends carrying to SGW/PGW and establishes request, Core-network side establishes EPC carryings, finally sets up EPS carryings.

Step 317：ENB check opposite end whether have been established wireless data carrying, if having been established wireless data carrying, eNB to Opposite end sends session switching command, and notice opposite end conversates switching, and being switched to EPS from D2D carryings carries.Session switching command Middle carrying source mark, D2D are carried to information such as the instructions of EPS carrying switchings.

Step 318：While opposite end carries transmission IP data packets by D2D again, forwarding IP data packets also are carried to EPS, It is interrupted as D2D is carried, source can also receive the IP data packets of opposite end by EPS carryings at this time.

Step 319~320：Opposite end returns to session switching to eNB and confirms response, and eNB confirms to MME return session switchings to be rung It answers.Opposite end mark, the IP address and tunnel id information of the eNB distributed for opposite end can be carried in the confirmation response that eNB is returned.

Step 321：After MME receives session switching confirmation response, optionally, bearing modification request can be initiated to SGW/PGW, Change the downlink bearing link of opposite end EPS carryings.

Step 322：After EPS carrying uplink downlinks are normal, the IP data packets of source can be carried by EPS receives and dispatches, no It is needing to carry by D2D.

Step 323：After D2D carryings are switched to EPS carryings, optionally, source and opposite end ask release D2D wireless to eNB Resource, notice source and opposite end discharge D2D radio resources after eNB decisions.

Embodiment three

The present embodiment mainly describes the D2D sources accessed in same eNB and opposite end and carries progress D2D meetings by EPS Words, movement has occurred in source at this time, enters the regions D2D.Whether D2D sessions are met for terminal detection D2D regional extents Scene, D2D terminals check can initiate D2D session switching requests when the regions D2D are critical to network side.Network side eNB is examined The scene whether D2D regional extents meet D2D sessions is surveyed, eNB checks that can initiate D2D sessions to MME when the regions D2D are critical cuts Change request；The no scene for meeting D2D sessions of D2D regional extents is checked for network side MME, MME is checked can when the regions D2D are critical D2D sessions switching whether is initiated with decision, then Radio Access Network eNB is notified to conversate switching.MME is according to D2D sessions Switching instruction carries out D2D communication checks and decision is initiated to be carried to the session switching that D2D is carried from EPS.Network side notifies terminal It executes session switching, source and opposite end to receive and dispatch IP sessions packet from D2D carryings, and optionally release EPS carryings, complete EPS carries the session handover operation carried to D2D.

Shown in Figure 6, the present embodiment specific steps are described as follows：

Step 401：D2D sources and the opposite ends D2D are all linked into EPS networks by same eNB, and network side is source and terminal Establish EPS carryings.D2D sources and terminal carry out D2D sessions using EPS bearing links.

Step 402：D2D sources are moved, and D2D regional extents are progressed into.If terminal and network all support D2D at this time Business and D2D abilities need to carry out to make core network data effectively shunt and the high QoS of terminal communication, low rate communication service Session switches.

If D2D terminals self-check D2D regional extents whether meet, such as can check other side wireless signal it is strong Weak, when finding that D2D regional extents are critical, D2D terminals can initiate session switching request to network side, and request is switched to D2D and holds It carries.

Step 403：After network side eNB receives the D2D session switching requests of terminal initiation, by the S1 interfaces with MME, to MME sends session switching request.

Step 404：After MME receives session switching request, indicated according to the D2D session switching requests in switching request, it is right Source and terminal carry out D2D communication checks, check whether with D2D abilities and D2D business of having contracted.And to source and terminal D2D regional extents checked, if the position of terminal met D2D sessions switching condition.Meet if checked It is required that MME just carries out D2D session handover operations.

Step 405：ENB where from MME to terminal sends session switching command, and notice eNB conversates switching.

Step 406：ENB is source and D2D radio resources, including LTE frequency spectrum resources, minislot parameter, QoS ginsengs are distributed in opposite end The information such as number.

Step 407：After eNB is terminal distribution D2D radio resources, session switching command message is sent to source, in message Including D2D radio resource parameters, opposite end mark and EPS are carried to D2D and are carried the information such as switching instruction.

Step 408：ENB sends session switching command message to opposite end, includes D2D radio resource parameters, source in message End mark and EPS are carried to D2D and are carried the information such as switching instruction.

Step 409：After source and opposite end receive D2D session switching commands, direct-connected D2D is set up according to the mark of other side Carrying, and transmitting-receiving IP data packets mutually are carried by D2D, the EPS sessions carried are switched in D2D carryings.

Step 410~411：Source returns to session switching to eNB and confirms response, and eNB confirms to MME return session switchings to be rung It answers.

Step 412：After MME receives session switching confirmation response, optionally, carrying deactivation can be initiated to SGW/PGW and is asked, Discharge EPC carryings；Optionally, S1 realizing interfaces are sent to eNB, asks releasing wireless loading.

Step 413~414：Opposite end returns to session switching to eNB and confirms response, and eNB confirms to MME return session switchings to be rung It answers.

Step 415：After MME receives session switching confirmation response, optionally, load bearing deactivation can be initiated to SGW/PGW and be asked It asks, release EPC carryings；Optionally, S1 realizing interfaces are sent to eNB, asks releasing wireless loading.

Step 416：EPS is carried after session that D2D is carried switches successfully, and optionally, eNB is deleted and source and opposite end RRC connections, releasing wireless loading resource.

Example IV

The present embodiment mainly describes the D2D sources accessed in adjacent eNB and opposite end and carries progress D2D meetings by D2D Words, movement has occurred in source at this time, has left the regions D2D.Whether D2D sessions are met for terminal detection D2D regional extents Scene, D2D terminals check can initiate D2D session switching requests when the regions D2D are critical to network side.Network side eNB is examined The scene whether D2D regional extents meet D2D sessions is surveyed, eNB checks that can initiate D2D sessions to MME when the regions D2D are critical cuts Change request；The no scene for meeting D2D sessions of D2D regional extents is checked for network side MME, MME is checked can when the regions D2D are critical D2D sessions switching whether is initiated with decision, then Radio Access Network eNB is notified to conversate switching.MME is according to D2D sessions Switching instruction carries out D2D communication checks and decision is initiated to be carried to the session switching that EPS is carried from D2D.If at terminal and opposite end In idle states, EPS bearer connections are interrupted, network elder generation call terminal, so that terminal is linked into network and are established EPS carryings.Network side is logical Know that terminal executes session switching, source and opposite end and receives and dispatches IP sessions packet from EPS carryings, and discharge D2D carryings, completes D2D carries the session handover operation carried to EPS.

Shown in Figure 7, the present embodiment specific steps are described as follows：

Step 501：D2D sources and the opposite ends D2D are all linked into EPS networks by adjacent eNB, and D2D sources connect from the first eNB Enter, the opposite ends D2D are accessed from the 2nd eNB, and D2D sources and opposite end are in D2D regional extents.Network side is that source and terminal establish D2D is carried, and source and opposite end can be at IDLE state, the release of EPS carryings at this time.D2D sources and terminal are carried out using D2D links D2D sessions.

Step 502：D2D sources are moved, and D2D regional extents are gradually left.At this time be prevent conversation, need into Guild's words switching.

Step 503：The first eNB of network side (or the 2nd eNB, this manuscript mainly describe source and the first eNB, opposite end and The flow that two eNB initiate session is similar, no longer carries out repeated description) receive the D2D session switching requests of terminal initiation after, can be with By the X2 interface with the 2nd eNB, or the S1 interfaces with MME, send session switching request, request switching to the 2nd eNB or MME It is carried to EPS.

If the first eNB of network side has the ability to check whether D2D regional extents meet according to relevant information, such as according to end Location information in the measurement report at end, or the D2D discovery mechanisms according to wireless access side.When the first eNB has found the regions D2D model When enclosing critical, the first eNB can carry source by sending session switching request with the X2 interface of the 2nd eNB in session switching request End mark, the information such as opposite end mark and D2D sessions switching instruction, request are switched to EPS carryings.

Step 504：After 2nd eNB receives the session switching request of the first eNB, which is passed through into S1 interfaces Issue MME.

Step 505：If not having X2 interface between eNB, the first eNB directly can be sent out session switching request by S1 interfaces To MME, request is switched to EPS carryings.

Step 506：After MME receives session switching request, indicated according to the D2D session switching requests in switching request, it is right Source and terminal carry out D2D communication checks, check whether with D2D abilities and D2D business of having contracted.And to source and terminal D2D regional extents checked, if the position of terminal met D2D sessions switching condition.Meet if checked It is required that MME just carries out D2D session handover operations.

Step 507：The first eNB where MME to source sends session switching command, notifies the first eNB conversates to cut It changes.

Step 508：If source is in idle states, EPS carryings are not set up, network side pages source, and activation is eventually It terminates into network and establishes EPS carryings.

After source receives paging, access request is sent to the first eNB, request is linked into network again, and eNB is by access request MME is issued, MME notices eNB is that source establishes wireless data carrying.MME sends carrying to SGW/PGW and establishes request, in core Net side establishes EPC carryings, finally sets up EPS carryings.

First eNB check source whether have been established wireless data carrying, if having been established wireless data carrying, the first eNB to Source sends session switching command, and notice source conversates switching, and being switched to EPS from D2D carryings carries.Session switching command Middle carrying opposite end mark, D2D are carried to information such as the instructions of EPS carrying switchings.

Step 509：Source returns to session switching to the first eNB and confirms that response, the first eNB are true to MME return session switchings Recognize response.Source mark, the IP address and tunnel ID of the eNB distributed for source can be carried in the confirmation response that first eNB is returned Information.

Step 510：After MME receives session switching confirmation response, optionally, bearing modification request can be initiated to SGW/PGW, The downlink bearing link for changing source EPS carryings ensures that downlink data can be carried by EPS and initiates source.

Step 511：While source carries transmission IP data packets by D2D again, forwarding IP data packets also are carried to EPS, It is interrupted as D2D is carried, opposite end can also receive the IP data packets of source by EPS carryings at this time.

After EPS carrying uplink downlinks are normal, the IP data packets of source can be carried by EPS receives and dispatches, and is not needing to lead to Cross D2D carryings.

Step 512：The 2nd eNB where MME to opposite end sends session switching command or request, and the 2nd eNB is notified to carry out Session switches.

Step 513：If opposite end is in idle states, EPS carryings are not set up, network side pages opposite end, and activation is eventually It terminates into network and establishes EPS carryings.

Step 514：After opposite end receives paging, access request is sent to the 2nd eNB, asks to be linked into network again, second Access request is issued MME by eNB, and MME notices eNB is that wireless data carrying is established in opposite end.MME sends carrying to SGW/PGW and builds Vertical request establishes EPC carryings in core-network side, finally sets up EPS carryings.

2nd eNB check opposite end whether have been established wireless data carrying, if having been established wireless data carrying, the 2nd eNB to Opposite end sends session switching command, and notice opposite end conversates switching, and being switched to EPS from D2D carryings carries.Session switching command Middle carrying source mark, D2D are carried to information such as the instructions of EPS carrying switchings.

Step 515：Opposite end returns to session switching to the 2nd eNB and confirms that response, the 2nd eNB are true to MME return session switchings Recognize response.Source mark, the IP address and tunnel of the 2nd eNB distributed for source can be carried in the confirmation response that 2nd eNB is returned Road id information.

Step 516：After MME receives session switching confirmation response, optionally, bearing modification request can be initiated to SGW/PGW, The downlink bearing link for changing source EPS carryings ensures that downlink data can be carried by EPS and initiates opposite end.

Step 517：While opposite end carries transmission IP data packets by D2D again, forwarding IP data packets also are carried to EPS, It is interrupted as D2D is carried, source can also receive the IP data packets of opposite end by EPS carryings at this time.

After EPS carrying uplink downlinks are normal, the IP data packets of opposite end can be carried by EPS receives and dispatches, and is not needing to lead to Cross D2D carryings.

Step 518：After D2D carryings are switched to EPS carryings, optionally, source and opposite end ask release D2D wireless to eNB Resource, notice source and opposite end discharge D2D radio resources after eNB decisions.

Step 519：D2D sessions are realized in source and opposite end in EPS carryings.

Embodiment five

The present embodiment mainly describes the D2D sources accessed in adjacent eNB and opposite end and carries progress D2D meetings by EPS Words, movement has occurred in source at this time, enters the regions D2D.Whether D2D sessions are met for terminal detection D2D regional extents Scene, D2D terminals check can initiate D2D session switching requests when the regions D2D are critical to network side.Network side eNB is examined The scene whether D2D regional extents meet D2D sessions is surveyed, eNB checks that can initiate D2D sessions to MME when the regions D2D are critical cuts Change request；The no scene for meeting D2D sessions of D2D regional extents is checked for network side MME, MME is checked can when the regions D2D are critical D2D sessions switching whether is initiated with decision, then Radio Access Network eNB is notified to conversate switching.MME is according to D2D sessions Switching instruction carries out D2D communication checks and decision is initiated to be carried to the session switching that D2D is carried from EPS.Network side notifies terminal It executes session switching, source and opposite end to receive and dispatch IP sessions packet from D2D carryings, and optionally release EPS carryings, complete EPS carries the session handover operation carried to D2D.

Shown in Figure 8, the present embodiment specific steps are described as follows：

Step 601：D2D sources and the opposite ends D2D are all linked into EPS networks by adjacent eNB, and D2D sources and opposite end are located at Except D2D regional extents.Network side is that source and terminal establish EPS carryings.D2D sources and terminal use EPS bearing links Carry out D2D sessions.

Step 602：D2D sources are moved, and D2D regional extents are progressed into.If terminal and network all support D2D at this time Business and D2D abilities need to carry out to make core network data effectively shunt and the high QoS of terminal communication, low rate communication service Session switches.

Step 603：The first eNB of network side (or the 2nd eNB, this manuscript mainly describe source and the first eNB, opposite end and The flow that two eNB initiate session is similar, no longer carries out repeated description) receive the D2D session switching requests of terminal initiation after, can be with By the X2 interface with the 2nd eNB, or the S1 interfaces with MME, send session switching request, request switching to the 2nd eNB or MME It is carried to D2D.

If the first eNB of network side has the ability to check whether D2D regional extents meet according to relevant information, such as according to end Location information in the measurement report at end, or the D2D discovery mechanisms according to wireless access side.When the first eNB has found the regions D2D model When enclosing critical, the first eNB can carry source by sending session switching request with the X2 interface of the 2nd eNB in session switching request End mark, the information such as opposite end mark and D2D sessions switching instruction, request are switched to D2D carryings.

Step 604：After 2nd eNB receives the session switching request of the first eNB, which is passed through into S1 interfaces Issue MME.

Step 605：If not having X2 interface between eNB, the first eNB directly can be sent out session switching request by S1 interfaces To MME, request is switched to D2D carryings.

Step 606：After MME receives session switching request, indicated according to the D2D session switching requests in switching request, it is right Source and terminal carry out D2D communication checks, check whether with D2D abilities and D2D business of having contracted.And to source and terminal D2D regional extents checked, if the position of terminal met D2D sessions switching condition.Meet if checked It is required that MME just carries out D2D session handover operations.

Step 607：The first eNB where MME to source sends session switching command, notifies the first eNB conversates to cut It changes.

Step 608：First eNB is that source distributes D2D radio resources, including LTE frequency spectrum resources, minislot parameter, qos parameter Etc. information.

Step 609：First eNB is to send session switching command message after source distributes D2D radio resources to source, disappear Include D2D radio resource parameters in breath, opposite end mark and EPS are carried to D2D and carried the information such as switching instruction.

Step 610：The 2nd eNB where MME to opposite end sends session switching command, notifies the 2nd eNB conversates to cut It changes.Source mark, the information such as opposite end mark and D2D sessions switching instruction are carried in session switching request or order.

Step 611：2nd eNB is that source distributes D2D radio resources, including LTE frequency spectrum resources, minislot parameter, qos parameter Etc. information.

Step 612：2nd eNB sends session switching command message to opposite end, includes D2D radio resource parameters in message, Source identifies and EPS is carried to D2D and carried the information such as switching instruction.

Step 613：After source and opposite end receive D2D session switching commands, direct-connected D2D is set up according to the mark of other side Carrying, and transmitting-receiving IP data packets mutually are carried by D2D, the EPS sessions carried are switched in D2D carryings.

Step 614~615：Source returns to session switching to the first eNB and confirms that response, the first eNB return to session to MME and cut Change confirmation response.

Step 616：After MME receives session switching confirmation response, optionally, carrying deactivation can be initiated to SGW/PGW and is asked, Discharge EPC carryings；Optionally, S1 realizing interfaces are sent to the first eNB, asks releasing wireless loading.

Step 617~618：Opposite end returns to session switching to the 2nd eNB and confirms that response, the 2nd eNB return to session to MME and cut Change confirmation response.

Step 619：After MME receives session switching confirmation response, optionally, carrying deactivation can be initiated to SGW/PGW and is asked, Discharge EPC carryings；Optionally, S1 realizing interfaces are sent to the 2nd eNB, asks releasing wireless loading.

Step 620：EPS is carried after the session that D2D is carried switches successfully, and optionally, the first eNB and the 2nd eNB are deleted It is connect with the RRC of source and opposite end, releasing wireless loading resource.

In addition, direct-connected communicating terminal session switching dress in additionally providing a kind of mobile communications network in the embodiment of the present invention It sets, is applied to D2D terminals, as shown in figure 9, described device includes mainly：

In addition, described device can also include：

In addition, direct-connected communicating terminal session switching dress in additionally providing a kind of mobile communications network in the embodiment of the present invention It sets, is applied to network side, as shown in figure 9, described device includes mainly：

Further, described device can also include：

The preferred implementation case that these are only the present invention, is not intended to restrict the invention, the present invention can also have other Various embodiments, without deviating from the spirit and substance of the present invention, those skilled in the art can be according to this hairs It is bright to make various corresponding change and deformations, but these corresponding change and deformations should all belong to appended claims of the invention Protection domain.

Obviously, those skilled in the art should be understood that each module of the above invention or each step can be with general Computing device realize that they can be concentrated on a single computing device, or be distributed in multiple computing devices and formed Network on, optionally, they can be realized with the program code that computing device can perform, it is thus possible to which they are stored It is performed by computing device in the storage device, and in some cases, it can be with different from shown in sequence execution herein The step of going out or describing, either they are fabricated to each integrated circuit modules or by them multiple modules or Step is fabricated to single integrated circuit module to realize.In this way, the present invention is not limited to any specific hardware and softwares to combine.

Claims

1. direct-connected communicating terminal conversation switching method in a kind of mobile communications network, which is characterized in that

During first direct-connected communication D2D terminals conversate with the 2nd D2D terminals, the base station of network side or mobile management Entity MME is according to the location information or the D2D discovery mechanisms of wireless access side or the D2D of core-network side in measurement report When discovery mechanism judges that D2D regional extents change, D2D session switching requests are initiated；Network side switches according to D2D sessions Decision is asked to initiate the switching of D2D carryings and evolved packet system EPS carryings；Comprising described in the D2D sessions switching request The terminal iidentification and D2D sessions switching instruction of first D2D terminals and the 2nd D2D terminals.

2. the method as described in claim 1, which is characterized in that the D2D regional extents change, including：

First D2D terminals and the into or out regions D2D of the 2nd D2D terminals.

3. method as claimed in claim 2, which is characterized in that

When first D2D terminals enter the regions D2D with the 2nd D2D terminals, network side decision initiates EPS and is carried to cutting for D2D carryings It changes；

When first D2D terminals leave the regions D2D with the 2nd D2D terminals, network side decision initiates D2D and is carried to cutting for EPS carryings It changes.

4. the method as described in claim 1, which is characterized in that the method further includes：

The network side carries out the first D2D terminals and the 2nd D2D terminals according to the D2D sessions switching request After D2D communication checks, decision initiates the switching of the D2D carryings and EPS carryings.

5. method as claimed in claim 4, which is characterized in that

The D2D communication checks, including following one or its arbitrary combination：The first D2D terminals and the 2nd D2D terminals D2D regional locations；The D2D abilities of the first D2D terminals and the 2nd D2D terminals；The D2D abilities of network side；It is described Whether the first D2D terminals and the 2nd D2D terminals contract D2D business.

6. method as claimed in claim 1,2 or 3, which is characterized in that the method further includes：

It is the first D2D terminals and the 2nd D2D after network side decision initiates the switching that the D2D carryings are carried with EPS Terminal distribution D2D bearing resources or EPS bearing resources.

7. the method as described in claim 1, which is characterized in that the method further includes：

When the first D2D terminals or the 2nd D2D terminals are in idle condition, network side is according to the terminal iidentification It is paged, the first D2D terminals or the 2nd D2D terminals is made to restore connected state.

8. direct-connected communicating terminal session switching device in a kind of mobile communications network, which is characterized in that it is applied to network side, it is described Device includes：

Session hand-off process module, for when the areas D2D for knowing the direct-connected communication D2D terminals and the opposite ends D2D that are conversating When domain range changes, decision initiates the switching of D2D carryings and EPS carryings；Decision is initiated D2D carryings and is cut with what EPS was carried After changing, terminal iidentification and the D2D sessions switching instruction of the D2D terminals and the opposite ends D2D are carried in session handover request, and Session switching command is sent to the D2D terminals and the opposite ends D2D；

The session hand-off process module be used to know in the following manner D2D terminals and the opposite ends D2D D2D regional extents whether It changes：According to the D2D discovery mechanisms of location information or wireless access side in measurement report or core-network side D2D discovery mechanisms.

9. device as claimed in claim 8, which is characterized in that described device further includes：

Communication service resource distribution module is used to distribute D2D communication service resources for the D2D terminals and the opposite ends D2D, including D2D bearing resources or EPS bearing resources.

10. device as claimed in claim 8, which is characterized in that described device further includes：

D2D communication services check module, for check requested D2D sessions switching whether meet one of following condition or its Meaning combination：The D2D regional locations of the D2D terminals and the opposite ends D2D；The D2D abilities of the D2D terminals and the opposite ends D2D；Network side D2D abilities；Whether the D2D terminals and the opposite ends D2D contract D2D business.

11. device as claimed in claim 8, which is characterized in that described device further includes：

Module is paged, for when the D2D terminals and the opposite ends D2D are in idle condition, according to the institute in session switching request The terminal iidentification for stating D2D terminals and the opposite ends D2D, carrying out paging to the D2D terminals and the opposite ends D2D makes it restore connected state.