KR102012255B1 - Method for direct communication - Google Patents

Abstract

When a forwarding terminal connected to a base station receives a multicast packet from the base station, the forwarding terminal establishes a multicast connection with at least one direct communication terminal having a direct communication group identifier mapped to the multicast IP address of the multicast packet, and then establishes a multicast connection. By transmitting the cast packet to at least one direct communication terminal, a multicast service is provided to a direct communication terminal not connected to the base station.

Description

Direct communication method {METHOD FOR DIRECT COMMUNICATION}

The present invention relates to a direct communication method, and more particularly, to a direct communication method capable of providing a service through a communication infrastructure to a terminal not connected to a communication infrastructure.

In an environment in which a communication infrastructure between a terminal and a base station is established, a method of performing direct communication between terminals using a specific resource region has been proposed. In such direct communication, it is necessary to use a communication infrastructure to exchange information with the backbone network or to expand the serviceable area.

In case of direct communication between terminals, a terminal that is not connected to the communication infrastructure may be provided with a service through the communication infrastructure by using a terminal connected to the communication infrastructure. However, there is a problem in that the base station manages a terminal that is not connected to the communication infrastructure.

The technical problem to be solved by the present invention is to provide a direct communication method that can provide a communication infrastructure service to a terminal that is not connected to the communication infrastructure without managing a terminal that is not connected to the communication infrastructure in the base station.

According to an embodiment of the present invention, a method of performing direct communication with a direct communication terminal that is not connected to a base station is connected to a base station is provided. The direct communication method includes receiving a multicast packet from the base station, establishing a multicast connection with at least one direct communication terminal having a direct communication group identifier mapped to the multicast IP address of the multicast packet, and Transmitting a multicast packet to the at least one direct communication terminal.

The setting may include transmitting a link setting command message for link setting to the at least one direct communication terminal, and the link setting command message may include the direct communication group identifier.

The direct communication method may further include performing a multicast delivery initiation procedure before the setting.

The performing of the multicast delivery initiation procedure may include broadcasting a delivery advertisement message for notifying service status information to a plurality of direct communication terminals.

The broadcasting may include broadcasting the delivery advertisement message periodically.

The delivery advertisement message may include at least one of an identifier of a delivery terminal, a serviceable direct communication group identifier list, and a direct communication group identifier list currently in service.

The performing of the multicast delivery initiation procedure may further include receiving a delivery join message from one of the at least one direct communication terminal, the delivery join message being a direct communication serviceable by the delivery terminal. The at least one direct communication terminal of the group separator list may include a direct communication group identifier mapped to a multicast packet to be received.

The performing of the multicast forwarding procedure may include: providing a multicast packet mapped to a direct communication group identifier included in the forward join message. The method may further include performing service connection establishment with the base station.

The direct communication method may further include releasing the multicast connection with the at least one direct communication terminal when there is no received signal for a predetermined time with the at least one direct communication terminal.

The releasing may include transmitting a direct communication link release command message to the at least one direct communication terminal, and the direct communication link release command message may include the direct communication group identifier.

The direct communication method may further include transmitting a unicast packet from one direct communication terminal to the base station while transmitting the multicast packet.

The transmitting of the unicast packet to the base station may include receiving a link establishment request message for establishing a unicast connection from the one direct communication terminal, and sending a response message for the link establishment request message to the one direct communication. And transmitting to the terminal, wherein the link establishment request message may include an identifier of the transmitting terminal and a direct communication group identifier currently in service as destination information.

The transmitting of the unicast packet to the base station may include receiving the unicast packet from the one direct communication terminal when the unicast connection is set, and converting the unicast packet into an IP packet to the base station. The method may further include transmitting.

The IP packet may include a server address mapped to a direct communication group identifier as a destination address and an address of the transmitting terminal as a source address.

The transmitting may include converting the multicast packet into a direct communication packet.

According to another embodiment of the present invention, a method of performing direct communication with a direct communication terminal that is not connected to a base station is connected to a base station is provided. In the direct communication method, receiving a multicast packet from the base station, and link setting command including the direct communication group identifier to at least one direct communication terminal having a direct communication group identifier mapped to the multicast IP address of the multicast packet. Transmitting a message, converting the multicast packet into a direct communication packet, and transmitting the direct communication packet to the at least one direct communication terminal.

The direct communication method may further include periodically broadcasting a delivery advertisement message for notifying service status information to a plurality of direct communication terminals, wherein the delivery advertisement message includes an identifier of a delivery terminal, a serviceable direct communication group identifier list, and a current It may include at least one of a list of the direct communication group identifier in service.

The direct communication method further includes the step of receiving a transfer join message from one of the at least one direct communication terminal of the direct communication terminal, wherein the transfer join message is the one of the direct communication group identifier list serviceable by the delivery terminal. The direct communication terminal may include a direct communication group identifier mapped to a multicast packet to be received.

The direct communication method may further include transmitting a direct communication link release command message to the at least one direct communication terminal when there is no reception signal for a predetermined time from the at least one direct communication terminal. The release command message may include the direct communication group identifier.

The direct communication method may include receiving a link establishment request message for establishing a unicast connection from one of the at least one direct communication terminal while transmitting the multicast packet, and responding to the link establishment request message. Transmitting a message to the one direct communication terminal, receiving a unicast packet from the one direct communication terminal, and converting the unicast packet into an IP packet and transmitting the IP packet to the base station, The link establishment request message includes an identifier of the transmitting terminal and a direct communication group identifier currently in service as destination information, and the IP packet is a server address and a source address mapped to the direct communication group identifier as a destination address of the transmitting terminal. May contain an address.

According to an embodiment of the present invention, at least one of the terminals participating in the direct communication between the terminals may exchange information with the backbone network through the base station.

In addition, the base station may provide a communication infrastructure service to a terminal not connected to the backbone network through a terminal capable of exchanging information with the backbone network without managing a terminal not connected to the backbone network.

1 is a view showing a direct communication environment according to an embodiment of the present invention.
2 is a diagram schematically showing some procedures for network entry of a delivery terminal according to an embodiment of the present invention.
3 is a diagram illustrating a downlink multicast service providing method according to an embodiment of the present invention.
4 is a diagram illustrating a method for providing uplink unicast according to an embodiment of the present invention.
5 is a diagram illustrating a multicast delivery initiation method according to an embodiment of the present invention.
6 is a diagram illustrating a multicast delivery interruption method according to an exemplary embodiment of the present invention.
7 is a diagram illustrating a delivery terminal and a base station according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification and claims, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Throughout the specification, a terminal is a mobile station (MS), mobile terminal (MT), subscriber station (SS), portable subscriber station (PSS), access terminal (access) It may refer to a terminal (AT), a user equipment (UE), or the like, and may include all or some functions of the terminal, MT, SS, PSS, AT, UE, and the like.

In addition, the base station (BS) may be a node B (node B), an advanced node B (evolved node B, eNodeB), an access point (AP), a radio access station (radio access station (RAS)), a transceiver base station ( It may refer to a base transceiver station (BTS), a mobile multihop relay (MMR) -BS, or the like, and may include all or a part of functions of the NodeB, eNodeB, AP, RAS, BTS, MMR-BS, and the like.

A direct communication method according to an embodiment of the present invention will now be described in detail with reference to the drawings.

1 is a view showing a direct communication environment according to an embodiment of the present invention.

Referring to FIG. 1, the direct communication system includes a plurality of direct communication terminals 110, 120, and 130.

The plurality of direct communication terminals 110, 120, and 130 are terminals capable of performing direct communication between terminals.

The plurality of direct communication terminals 110, 120, and 130 may be forwarding terminals according to their capabilities. In order to support the unicast transmission of the direct communication terminal belonging to the lower level, the transmitting terminal should not only be able to receive the direct communication traffic between the terminals, but also be able to receive the connection attempt of the direct communication terminal belonging to the lower level at any time. In addition, the transmitting terminal should be able to perform a protocol conversion function between the direct communication service and the infrastructure communication service. A direct communication terminal capable of performing such a function among the direct communication terminals 110, 120, and 130 may be a delivery terminal. That is, the transmitting terminal refers to a terminal that is connected to the base station 200 of the backbone network and can perform infrastructure communication with the base station 200 and also perform direct communication between terminals. In FIG. 1, it is assumed that the direct communication terminal 110 is a delivery terminal, and for convenience of description, the direct communication terminal 110 is referred to as a delivery terminal 110.

The delivery terminal 110 may include an infrastructure communication interface and a direct communication interface. Therefore, the delivery terminal 110 performs a protocol conversion function between the infrastructure communication and the direct communication between the terminals, and can operate the direct communication and the infrastructure communication independently. The transmitting terminal 110 is limited in power that can be transmitted, and may not simultaneously transmit infrastructure communication data and direct communication data between terminals in an uplink subframe. This is because when the infrastructure communication data and the direct communication data between terminals are transmitted at the same time, data cannot be properly transmitted to the destination, thereby reducing the transmission efficiency.

The direct communication terminals 120 and 130 are terminals not connected to the backbone network, and may receive the infrastructure communication service from the base station 200 without being allocated an IP address for the infrastructure communication service. That is, the direct communication terminals 120 and 130 are lower direct communication terminals of the delivery terminal 110 and may receive an infrastructure communication service through the delivery terminal 110.

Infrastructure communication services that can be provided through the delivery terminal 110 may include a downlink multicast service and an uplink unicast service.

The direct communication terminals 120 and 130 may use the IP address of the transmitting terminal 110 for uplink unicast service. For the downlink unicast service, it is difficult for the transmitting terminal 110 to allocate, terminate, and manage addresses for distinguishing direct communication flows for each of the direct communication terminals 120 and 130. Therefore, the infrastructure communication service according to an embodiment of the present invention does not include a downlink unicast service.

The delivery terminal 110 may map and manage a direct communication group identifier (DCGID) and a multicast IP address through which multicast is transmitted to provide a downlink multicast service.

That is, the direct communication terminals 120 and 130 may be included in a direct communication group preset for the multicast service, and the direct communication terminals 120 and 130 may belong to the same group or different groups. The direct communication terminals 120 and 130 know in advance the DCGID, which is a delimiter for distinguishing the direct communication group to which the terminal belongs.

The delivery terminal 110 manages the mapping between the DCGID and the multicast IP address through which the multicast is transmitted to deliver the multicast traffic to the direct communication group.

The transmitting terminal 110 knows in advance the DCGID list that can be delivered and the IP address of the multicast service mapped thereto, and the message (AAI-DC-) of the lower direct communication terminals 120 and 130 in the direct communication group list. The mapping of DCGID and multicast IP address received by FWD-JOIN is activated, and only traffic corresponding to the activated mapping is delivered. However, in the case of a broadcast service, traffic can always be delivered without any other setting.

In addition, the transmitting terminal 110 is an address of an application server (not shown) that provides a DCGID and a downlink multicast service to provide an uplink unicast service of the direct communication terminals 120 and 130 during the downlink multicast service. Manage by mapping. The address of the application server providing the multicast service may be obtained by using source IP address information of downlink multicast traffic.

2 is a diagram schematically showing some procedures for network entry of a delivery terminal according to an embodiment of the present invention.

Referring to FIG. 2, the delivery terminal 110 performs a basic capability negotiation process with the base station 200 to enter a network.

The transmitting terminal 110 transmits an Advanced Air Interface-Subscriber Station Basic Capability Request (AAI-SBC-REQ) message for basic capability negotiation to the base station 200 (S210). The AAI-SBC-REQ message is a message transmitted by the transmitting terminal 110 to negotiate basic performance with the base station 200. As shown in Table 1, the AAI-SBC-REQ message indicates information on whether to support delivery capability. Include. The transmission capability is information indicating whether the transmission terminal 110 is capable of transferring data between the base station 200 and the direct communication terminals 120 and 130. That is, the delivery terminal 110 may notify the base station 200 whether the base station 200 supports the delivery capability through the AAI-SBC-REQ message.

Field Size (bits) Value / Description Condition … … If (HR-RS is the sender of AAI-SBC-REQ) { Local Forwarding Capability 2 0b00: LF is not supported
0b01: HR-RS detects LF opportunity and performs LF
0b10: HR-RS does not detect LF opportunity but can perform LF
0b11: reserved Present if needed in HR Network } Direct Communication Forwarding Capability supported One 0x0: the capability as a Forwarding HR-MS is not supported
0x1: the capability as a Forwarding HR-MS is supported
Present during the network entry procedure of HR-MS having the capability of Talk-around Direct Communication For (i = 0; i <N_Slot; i ++) { N_Slot is the number of Direct Mode Slot in the Talk-around Direct Communication frame structure to prevent an HR-BS from allocating the corresponding subframes for the HR-MS in order to support forwarding to the network Present if Direct Communication Forwarding Capability supported == 1 Direct Mode Zone Type 2
Direct mode zone type for preventing an HR-BS from allocating downlink or uplink subframes
0x0: Common direct mode zone (CDMZ)
0x1: Common direct mode zone extended
(CDMZ-E)
0x2: Cell specific direct mode zone (CSDMZ)
0x3: Reserved. Direct Mode Slot Number prohibiting allocation One Slot Number in the Talk-around Direct Communication frame structure to prevent an HR-BS from allocation of the infra-structure resources for the corresponding subframes for the HR-MS
0x0: Slot 1
0x1: Slot 2 }

As shown in Table 1, when the transmitting terminal 110 supports the transmission capability, the subframe and the base station 200 to which the transmitting terminal 110 should receive uplink data from the direct communication terminals 120 and 130 are transmitted to the transmitting terminal. In order to prevent the subframes for allocating uplink resources for uplink transmission to the base station 200 from overlapping with each other, the AAI-SBC-REQ message includes a forwarding terminal 110 among radio resources for direct communication. It further includes a direct mode zone type (Direct Mode Zone Type) that is a direct communication resource information identifier for preventing uplink resource allocation of the base station 200 and a slot number (Direct Mode Slot Number prohibiting allocation) which should not be allocated resources. Can be.

When the base station 200 receives the AAI-SBC-REQ message from the forwarding terminal 110, the base station 200 transmits an AAI-Subscriber Station Basic Capability Response (AAI-SBC-RSP) message to the forwarding terminal 110. Informs the common providing capability of the delivery terminal 110 and the base station 200 (S220). AAI-SBC-RSP message may be as shown in Table 2.

Field Size
( bits ) Value Of Description Conditions Local Forwarding Capability 2 0 b00 : LF is not allowed
0 b01 : HR - BS detects LF  opportunity and HR - RS  performs LF as needed
0 b10 : HR - RS detects LF  opportunity and HR - RS  performs LF as needed
0 b11 : ASN detects LF  opportunity and HR - RS  performs LF as needed Present if needed in  HR Network Direct  Communication Forwarding Capability supported One 0x0: the capability as  a Forwarding HR - MS
0x1: the capability as  a Forwarding HR - MS is supported
Present during the  network entry  procedure of HR - MS  having the capability of  Talk-around Direct Communication For  (i = 0; i <N_Slot; i ++) { N_ Slot is the number of Direct  Mode Slot in the Talk - around  Direct Communication frame  structure to prevent an HR - BS  from allocating the  corresponding subframes for  the HR - MS in order to support  forwarding to the network Present if Direct  Communication Forwarding Capability  supported == 1 Direct Mode  Zone Type 2
Direct mode zone type for  preventing an HR - BS from  allocating downlink or uplink subframes
0x0: Common direct mode zone  ( CDMZ )
0x1: Common direct mode zone extended
( CDMZ -E)
0x2: Cell specific direct mode  zone ( CSDMZ )
0x3: Reserved . Direct Mode Slot  Number prohibiting allocation One Slot Number in the Talk - around  Direct Communication frame  structure to prevent an HR - BS  from allocation of the  infra-structure resources for the  corresponding subframes for  the HR - MS
0x0: Slot  One
0x1: Slot  2 }

The transmitting terminal 110 completes the basic capability negotiation process by receiving an AAI-SBC-RSP message from the base station 200.

3 is a diagram illustrating a downlink multicast service providing method according to an embodiment of the present invention.

Referring to FIG. 3, upon receiving a multicast packet from an external application server, the base station 200 transmits a multicast packet using a pre-mapped flow identifier (FID) or a multicast IP address. 110 to transmit (S310). The multicast packet has one FID or multicast IP address, and the FID or multicast IP address is mapped to the DCGID of the direct communication terminal.

The forwarding terminal 110 receiving the multicast packet checks whether a DCGID mapped to the FID or multicast IP address exists, and if the DCGID mapped to the FID or multicast IP address exists, establishes a direct communication multicast connection between terminals. Do this.

In order to perform the direct communication multicast connection setup between terminals, the transmitting terminal 110 transmits a preamble to the direct communication terminals 120 and 130 having the corresponding DCGID (S320). Next, the transmission terminal 110 transmits a link establishment command (AAI-DC-Link establishment command, AAI-DC-LEST-CMD) message to the direct communication terminal (120, 130) (S330). At this time, the transmitting terminal 110 transmits a link setup command (AAI-DC-LEST-CMD) message to the direct communication terminals 120 and 130 as a piggyback in a request to send (RTS) message to indicate that data transmission is desired. Can be. The link establishment command (AAI-DC-LEST-CMD) message may include a DCGID. When the direct communication terminal 120 or 130 successfully receives the link setup command message, the direct communication terminal 120 or 130 may transmit a successful reception (ACK) to the auxiliary channel (S340) or may not transmit the received link setup command message.

In this way, upon completing the direct communication multicast connection setup between terminals, the delivery terminal 110 converts the multicast packets into direct communication packets (DC PDUs) and delivers direct communication packets (DC PDUs) (S350).

If the multicast packet is not received from the application server for a predetermined time, the transmitting terminal 110 may transmit a null packet to the direct communication terminals 120 and 130 to maintain the direct communication multicast connection between the terminals. (S360).

When the multicast packet is received from the application server, the multicast packet may be converted into direct communication packets (DC PDUs) through the established multicast connection, and the direct communication packets (DC PDUs) may be delivered.

In this manner, the direct communication terminals 120 and 130 may receive downlink multicast services from the base station 200 without being connected to the base station 200. As such, when the direct communication terminals 120 and 130 become talkers in the group communication while receiving the downlink multicast service from the base station 200, the uplink unicast setting may be requested.

4 is a diagram illustrating a method for providing uplink unicast according to an embodiment of the present invention.

Referring to FIG. 4, when the direct communication terminal 120 is to be a talker among the direct communication terminals 120 and 130 that are provided with the downlink multicast service from the base station 200 through the delivery terminal 110, The direct communication terminal 120 performs a unicast connection setup procedure with the transmitting terminal 110 to transmit the uplink unicast packet.

The direct communication terminal 120 transmits the preamble to the delivery terminal 110 to perform the unicast connection setup (S402). Next, the direct communication terminal 120 transmits a link establishment request (AAI-LEST-REQ) message to the delivery terminal 110 (S404). In this case, the direct communication terminal 120 may transmit a link establishment request (AAI-LEST-REQ) message to the delivery terminal 110 as a piggyback to the RTS message. The RTS message may include a source DCTID and a destination DCTID of the direct communication terminal 120 to transmit an uplink unicast packet. In addition, as shown in Table 3, the link establishment request (AAI-LEST-REQ) message includes a forwarding request indicator indicating whether the direct communication terminal 120 is configured for forwarding traffic. The communication terminal 120 may include a target DCGID (DCGID) of the multicast service that is being received. In this case, the destination DCTID is a DCTID of the transmitting terminal 110. In particular, the delivery terminal 110 manages a destination address of traffic received by the delivery terminal 110 from the direct communication terminal 120 from the DCGID (target DCGID) of the multicast service provided by the direct communication terminal 120. Can be obtained by using the mapping information of DCGID and multicast IP address. This provides the advantage that the communication terminal does not have to directly manage the destination IP address of the unicast uplink traffic.

Field Size (bits) Value / Description Condition Link Change Count 4 The change count of this transaction assigned by the sender. If new transaction is started, Link Change Count is incremented by one (modulo 16) by the sender. Shall always be present For (i = 0; i <N_Flow_Est; i ++) { N_Flow_Est is the number of flows on which the sender of this message sends MAC PDUs.
Range [0..1] FID 4 Flow identifier assigned by the source station of packets on the flow Traffic priority 3 0 to 7: Higher numbers indicate higher priority
Default: 0 CS Specification Parameters 8 0-15: Reserved
16: Voice Codec G.729A
17: Voice Codec AMR
18-255: Reserved MAC Header Type One Indicates whether AGMH or SPMH is presented at the start of MAC PDUs of the service flow.
0: AGMH (Advanced Generic MAC Header)
1: SPMH (Short-Packet MAC header)
default value is 0. } Forwarding Request Indicator One Indicate that an HR-MS requests forwarding to network
0b0: Not request forwarding to network
0b1: Request forwarding to network Target DCGID 24 DC Group Identifier.
Indicate that the target address for forwarding to network Reserved 2

When the delivery terminal 110 successfully receives the link establishment request (AAI-LEST-REQ) message, it transmits whether the message is received to the direct communication terminal 120, for example, a successful reception (ACK) on the auxiliary channel (S406). ).

Next, the delivery terminal 110 transmits the preamble to the direct communication terminal 120 (S408). In direct communication between terminals, the preamble is used to achieve distributed synchronization.

The transmitting terminal 110 transmits an AAI-direct communication link establishment response (AAI-DC-LEST-RSP) message to the AAI-LEST-REQ message to the direct communication terminal 120. (S410).

The transmitting terminal 110 may transmit an AAI-DC-LEST-RSP (AAI-DC-LEST-RSP) message to the direct communication terminal 120 as a piggyback in a clear to send (CTS) message indicating that the data transmission is accepted. have.

When the direct communication terminal 120 successfully receives an AAI-DC-LEST-RSP message, the direct communication terminal 120 transmits a reception success (ACK) to the delivery terminal 110 (S412).

In this way, when the unicast connection setup between the direct communication terminal 120 and the delivery terminal 110 is completed, the direct communication terminal 120 transmits uplink traffic (DC PDUs) to the delivery terminal 110 (S414). ).

When receiving the uplink traffic (DC PDUs), the delivery terminal 110 converts the traffic received from the direct communication terminal 120 into an IP packet and transmits the IP packet to the base station 200 (S416). At this time, the destination address of the IP packet is the address of the application server 300 mapped to the DCGID, the source address is the IP address of the delivery terminal (110). In addition, the transmission terminal 110 transmits a successful reception (ACK) of uplink traffic (DC PDUs) to the direct communication terminal 120 to the direct communication terminal 120 (S418). In this case, the transmitting terminal 110 may inform the other direct communication terminal 130 below that the uplink unicast service is in progress, thereby preventing the direct communication terminal 130 from requesting transmission of the uplink unicast.

When the base station 200 receives the IP packet, the base station 200 may transmit the IP packet to the application server 300 corresponding to the destination address (S420).

After completing the uplink unicast service in this way, the base station 200 may again provide the downlink multicast service to the direct communication terminal 120 through the delivery terminal 110 (S422 to S426).

Meanwhile, the direct communication terminal 120 may terminate the connected unicast connection setting, and terminate the connection setting to terminate the unicast connection setting (AAI-DC-Link Release-Command, AAI-DC-LREL-CMD ) Transmits the message to the delivery terminal 110 (S428).

When the delivery terminal 110 successfully receives the connection establishment termination (AAI-DC-LREL-CMD) message, the transmission terminal 110 transmits a successful reception (ACK) to the direct communication terminal 120 through the auxiliary channel (S430).

When the direct communication terminal 120 receives the reception success (ACK), the direct communication terminal 120 may terminate the connection setup.

After the network entry procedure between the transmitting terminal 110 and the base station 200 is completed, the transmitting terminal 110 must first perform a multicast transmission starting procedure to provide a downlink multicast service. That is, the multicast delivery start procedure is performed before the multicast connection is established.

5 is a diagram illustrating a multicast delivery initiation method according to an embodiment of the present invention.

Referring to FIG. 5, after the network entry procedure between the transmitting terminal 110 and the base station 200 is completed, the transmitting terminal 110 may multiply with the direct communication terminals 120 and 130 to provide a downlink multicast service. Perform a cast delivery initiation procedure.

The delivery terminal 110 transmits the preamble to the direct communication terminals 120 and 130 to start multicast delivery (S510).

Next, the delivery terminal 110 transmits an AAI-DC-forwarding-advertisement (AAI-DC-FWD-ADV) message to the RTS message to the direct communication terminals 120 and 130 (S520). As shown in Table 4, the delivery advertisement (AAI-DC-FWD-ADV) message includes an identifier (DCTID), a serviceable DCGID list (Candidate DCGID), and a service DCGID list (On-Going DCGID) of the delivery terminal 110. It may include a resource for unicast (service slot) and the message change count (Message Change Count).

The delivery terminal 110 knows in advance the DCGID list that can be delivered and the IP address of the multicast service mapped thereto, and the DCGID is a DCGID list (Candidate) that can be serviced in a delivery advertisement (AAI-DC-FWD-ADV) message. DCGID). The transmitting terminal 110 transmits only traffic corresponding to the DCGID received by the message (AAI-DC-FWD-JOIN) of the direct communication terminals 120 and 130 among the serviceable DCGID list, and the corresponding DCGID is the transmitting terminal ( It is registered in the on-going DCGID (Service-On-Going DCGID) list managed by the 110, the delivery terminal 110 broadcasts the DCGID including the on-going DCGID (Service-On-Going DCGID) list. However, in case of the broadcast service, all direct communication terminals can receive the DCGID that is serving the broadcast identifier in the delivery advertisement (AAI-DC-FWD-ADV) message without a specific message (AAI-DC-FWD-JOIN). It can be included in the list and transmitted.

In addition, the transmitting terminal 110 establishes a unicast connection with the direct communication terminals 120 and 130, and notifies the direct communication terminals 120 and 130 through a forwarding unicast status that an uplink is in use. As a result, an unnecessary uplink connection attempt of the direct communication terminal 120 or 130 may be prevented.

Field Size (bits) Value / Description Condition Forwarding DCTID 24 DC Terminal Identifier.
Indicate the HR-MS which forwards the direct communication data between HR-BS and HR-MSs which are not connected to the infra-structure Shall always be present For (i = 0; i <N_Candidate_DCGID; i ++) { N_Candidate_DCGID is the number of Group Service which can be served by the forwarding HR-MS
Range [0..36] Candidate DCGID 24 DC Group Identifier.
Indicate a DC Group list which can be supported by the forwarding HR-MS } For (i = 0; i <N_On-Going_DCGID; i ++) { N_On-Going_DCGID is the number of on-going Group Service which is served by the forwarding HR-MS
Range [0..36] On-Going DCGID 24 DC Group Identifier.
Indicate a DC Group list which is currently served by the forwarding HR-MS } Forwarding Unicast Status One Indicate that the Forwarding HR-MS is available for forwarding unicast services toward HR-BS
0x0: available
0x1: currently forwarding packets Message Change Count 4 Message Change Count from the corresponding AAI-FWD-ADV - Reserved 2

That is, the delivery advertisement (AAI-DC-FWD-ADV) message informs the neighboring direct communication terminal that the delivery terminal 110 has a delivery capability to the backbone network, a serviceable DCGID list (Candidate DCGID), and the DCGID currently in service. A message for broadcasting service status information including list information and the like. The serviceable DCGID list means a list in which traffic is not delivered to the direct communication terminals 120 and 130. The DCGID list currently in service refers to a list that is transmitting traffic to or is going to transmit traffic to the direct communication terminals 120 and 130.

The delivery terminal 110 may periodically broadcast a delivery advertisement (AAI-DC-FWD-ADV) message.

The direct communication terminal (120, 130) receives a delivery advertisement (AAI-DC-FWD-ADV) message from the delivery terminal 110, and then delivers the preamble to request multicast delivery for the multicast group to receive Transmission to the terminal 110 (S530).

Next, the direct communication terminal (120, 130) transmits a transfer join (AAI-DC-FWD-JOIN) message to the delivery terminal 110 (S540). The AAI-DC-FWD-JOIN message may be used to receive a DCGID that is not currently being serviced in an AAI-DC-FWD-ADV message. As shown in Table 5, the AAI-DC-FWD-JOIN message may include a DCGID to be received. The DCGID to be received may be one of a list of serviceable DCGIDs in an AAI-DC-FWD-ADV message.

Field Size (bits) Value / Description Condition For (i = 0; i <N_DCGID; i ++) { N_DCGID is the number of Group identifier which are subscribed by an HR-MS, but are not in the on-going DCGID of AAI-DC-FWD-ADV
Range [0..36] DCGID 24 DC Group Identifier. }

Upon receiving the AAI-DC-FWD-JOIN message, the delivery terminal 110 transmits a message confirm indication to the direct communication terminals 120 and 130 (S550).

Next, the delivery terminal 110 transmits the preamble to the direct communication terminal (120, 130) for the service update (S560), and transmits the advertisement (AAI-DC-FWD-ADV) message with the RTS message to the direct communication terminal ( By transmitting to the 120, 130 (S570), the service update is notified to the direct communication terminal (120, 130). At this time, the direct communication terminal (120, 130) may check the DCGID requested by the received delivery advertisement (AAI-DC-FWD-ADV) message.

Next, as described with reference to FIG. 3, the delivery terminal 110 may provide a multicast packet to the direct communication terminals 120 and 130 after performing the multicast connection setup.

On the other hand, when a new direct communication terminal appears, the new direct communication terminal is requested to the AAI-DC-FWD-ADV before requesting the delivery terminal 110 DCGIDs that they want to receive (AAI-DC-FWD-JOIN) Check if there is a DCGID to receive and if the on-goding DCGID list in service includes the DCGID that it wants to receive, multicast periodic preamble and link connection establishment command (AAI-DC-). LEST-CMD) Wait for the reception of the message.

6 is a diagram illustrating a multicast delivery interruption method according to an exemplary embodiment of the present invention.

Referring to FIG. 6, when the delivery terminal 110 provides a multicast service to the direct communication terminals 120 and 130, if there is no signal received from the direct communication terminals 120 and 130 for a predetermined time through an auxiliary channel, To stop multicast service delivery, a multicast disconnection procedure may be performed.

In order to perform the multicast disconnection procedure, the transmitting terminal 110 transmits a direct communication link release command (AAI-DC-Link Release Command, AAI-DC-LREL-CMD) by multicasting, thereby performing direct communication link release. It performs (S610). In addition, the delivery terminal 110 performs a service release with the base station (S620). The direct communication link release command (AAI-DC-LREL-CMD) message may include a DCGID to be released.

7 is a diagram illustrating a delivery terminal and a base station according to an embodiment of the present invention.

Referring to FIG. 7, the delivery terminal 110 includes a processor 112, a memory 114, and a radio frequency (RF) unit 116. Base station 200 includes a processor 210, a memory 220, and an RF unit 230.

The processors 112 and 210 may be configured to implement the procedures and / or methods proposed in the embodiments of the present invention. The memories 114 and 220 are connected to the processors 112 and 210 and store various information related to the operation of the processors 112 and 210. The RF units 116 and 230 are connected with the processors 112 and 210 and transmit and / or receive radio signals. The base station 200 and / or the transmitting terminal 110 may have a single antenna or multiple antennas.

In addition, the direct communication terminals 120 and 130 may also be configured in the same manner as the delivery terminal 110.

An embodiment of the present invention is not implemented only through the above-described apparatus and / or method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Such an implementation can be easily implemented by those skilled in the art to which the present invention pertains based on the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (20)

A method for performing direct communication with a direct communication terminal that is not connected to a base station is connected to a base station connected to a base station,
Receiving a multicast packet from the base station,
Establishing a multicast connection with at least one direct communication terminal having a direct communication group identifier mapped to the multicast IP address of the multicast packet, and
Transmitting the multicast packet to the at least one direct communication terminal.
Direct communication method comprising a. In claim 1,
The setting may include transmitting a link setting command message for link setting to the at least one direct communication terminal. delete In claim 1,
Broadcasting a delivery advertisement message for notifying service status information to a plurality of direct communication terminals;
Direct communication method further comprising. delete In claim 4,
The delivery advertisement message includes at least one of an identifier of a delivery terminal, a serviceable direct communication group identifier list, and a direct communication group identifier list currently in service. In claim 6,
Receiving a delivery join message from the at least one direct communication terminal receiving the delivery advertising message;
More,
The forward join message includes a direct communication group identifier mapped to a multicast packet to be received by the at least one direct communication terminal among a list of direct communication group identifiers available to the delivery terminal. In claim 7,
Performing service connection establishment with the base station to provide a multicast packet mapped to the direct communication group identifier included in the forward join message.
Direct communication method further comprising. In claim 1,
Releasing the multicast connection with the at least one direct communication terminal when there is no received signal for a set time with the at least one direct communication terminal.
Direct communication method further comprising. In claim 9,
The canceling step includes the step of transmitting a direct communication link release command message to the at least one direct communication terminal. In claim 1,
Transmitting a unicast packet from one direct communication terminal to the base station
Direct communication method further comprising. In claim 11,
The step of transmitting the unicast packet to the base station
Receiving a link establishment request message for establishing a unicast connection from the one direct communication terminal, and
Transmitting a response message to the link establishment request message to the one direct communication terminal;
The link establishment request message includes a direct communication group identifier currently serving as destination information. delete delete delete A method for performing direct communication with a direct communication terminal that is not connected to a base station is connected to a base station connected to a base station,
Receiving a multicast packet from the base station,
Transmitting a link establishment command message including the direct communication group identifier to at least one direct communication terminal having the direct communication group identifier mapped to the multicast IP address of the multicast packet, and
Transmitting the multicast packet to the at least one direct communication terminal.
Direct communication method comprising a. The method of claim 16,
Broadcasting a delivery advertisement message for notifying service status information to a plurality of direct communication terminals;
More,
The delivery advertisement message includes at least one of an identifier of a delivery terminal, a serviceable direct communication group identifier list, and a direct communication group identifier list currently in service. The method of claim 17,
Receiving a transfer join message from one of the at least one direct communication terminal;
More,
The transfer join message includes a direct communication group identifier mapped to a multicast packet to be received by the one direct communication terminal among a list of direct communication group identifiers that can be serviced by a transmitting terminal. The method of claim 16,
And transmitting a direct communication link release command message to the at least one direct communication terminal when there is no reception signal for a predetermined time from the at least one direct communication terminal. The method of claim 16,
Receiving a link establishment request message for establishing a unicast connection from one of the at least one direct communication terminal;
Transmitting a response message to the link establishment request message to the one direct communication terminal, and
Receiving a unicast packet from the one direct communication terminal
More,
The link establishment request message includes a direct communication group identifier currently serving as destination information.

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