KR101001378B1 - Method and apparatus for updating topology in ofdma/tdd system - Google Patents

Abstract

PURPOSE: A method and a device for updating the net structure in anOFDMA/TDD are provided to effectively update the net structure of all terminals. CONSTITUTION: A base station(100) transmits update request message of a network structure through a control line slot. A terminal 1(110) transmits a message including the information about the quality of one link at least one connected to the terminal 1. The base station transmits the update request message of the network structure to a terminal 2(120). The terminal 2 transmits the message including the information about the quality of at least one ling connected to the terminal 1 to the base station.

Description

Method and apparatus for updating network structure in OPDMA / TDD system

The present invention relates to a method and apparatus for updating a network structure in an orthogonal frequency division multiple access (OFDMA) system, and more particularly, to an OFDMA based on a time division duplexing (TDD) scheme. A method and apparatus for updating a network structure in a system.

Recently, in the mobile communication system, the OFDM transmission scheme has been actively studied as a method useful for high-speed data transmission in a wireless channel. The OFDM scheme is a method of transmitting data using a multi-carrier, and converts a series of symbol strings serially inputted in parallel so that each of them has a plurality of sub-carriers having mutual orthogonality. That is, it is a type of Multi Carrier Modulation (MCM) that modulates and transmits a plurality of subcarrier channels.

Meanwhile, TDD, which is a method of distinguishing uplink and downlink, is currently being applied / researched to the 2.3GHz band portable Internet method as in Wibro and UMB (Ultra Mobile). Broadband systems are also being considered.

In the TDD scheme, a base station and a mobile terminal use the same frequency band to transmit data, thereby increasing frequency use efficiency, and supporting bidirectional transmission by allocating different slots in time.

In order to support multi-hop communication in an OFDMA system based on the TDD scheme, a method for efficiently and continuously updating information on a network structure is needed.The OSPF (Open Shortest Path First) and AODV (Adhoc On-demand distance Vector) The routing protocol according to the related art has a problem in that there is insufficient support for mobility or an optimized path search considering the state of the entire network is impossible.

SUMMARY OF THE INVENTION The present invention provides a method and apparatus for updating a network structure more stably and efficiently in an OFDMA system based on a TDD scheme, and a computer readable recording recording a program for executing the method. To provide the medium.

In the OFDMA / TDD system according to an embodiment of the present invention for solving the technical problem, a method for updating a network topology (topology) is a first request for updating the network structure through a first slot of a transmission frame Transmitting a message to a predetermined terminal having a hop number of 1 with the base station; Receiving a second message from the predetermined terminal, the second message including information on a quality of a link between the predetermined terminal and another terminal through a second slot of a transmission frame; And updating the network structure based on the second message, wherein the transmission frame includes the first slot, the second slot, and terminals included in the network of another terminal having a hop count of 2 or more from the base station. A third slot for relaying data and a terminal included in the network includes a fourth slot for transmitting data to the base station.

According to another embodiment of the present invention, the first slot is characterized in that the base station is assigned to the time slot in the transmission frame to transmit information for the operation of the network to the terminals included in the network. .

According to another embodiment of the present invention, the second slot is characterized in that the slots are allocated in the time frame in the transmission frame in order for the terminals included in the network to transmit and receive a predetermined message without passing through the base station.

According to another embodiment of the present invention, the fourth slot includes a plurality of sub-slots allocated in frequency division in the fourth slot for simultaneously transmitting data through different frequency bands.

According to another embodiment of the present invention, the updating of the network structure based on the second message may include transmitting the first message and transmitting the first message to all terminals having a hop number of 1 with the base station. Repeating reception; And updating the network structure based on a plurality of second messages received from all terminals included in the network.

In order to solve the above technical problem, in the OFDMA / TDD system, a method of updating a network topology by a base station includes: requesting a search for a second terminal having a hop number of 2 or more with the base station through a first slot of a transmission frame; Transmitting a 1 message to a first terminal having a hop number of 1 with the base station; Receiving a second message from the first terminal, the second message including information about a quality of a link between the second terminal and another terminal through a second slot of a transmission frame; And updating the network structure based on the second message, wherein the transmission frame is different in that the at least one terminal included in the first slot, the second slot, and the network has a hop count of 2 or more from the base station. A third slot for relaying data of the terminal and at least one terminal included in the network includes a fourth slot for transmitting data to the base station.

According to another embodiment of the present invention, the first terminal transmits a third message requesting the update of the network structure to the second terminal through a first slot of a transmission frame based on the first message, In response to the third message, a fourth message including information on a quality of a link between the second terminal and another terminal is received through a second slot of a transmission frame.

In order to solve the above technical problem, the present invention provides a computer-readable recording medium having recorded thereon a program for executing the method of updating the network structure described above.

According to the present invention, it is possible to stably and efficiently update the network structure of all the terminals, including the terminal connected to the base station and multi-hop.

1 illustrates an OFDMA / TDD system according to an embodiment of the present invention.
2 illustrates a structure of a TDD transmission frame for multihop communication in an OFDMA / TDD system according to an embodiment of the present invention.
3 illustrates a method of updating a network structure according to an embodiment of the present invention.
4 illustrates a transmission frame for transmitting and receiving information for updating a network structure according to an embodiment of the present invention.
5 illustrates a message requesting an update of a network structure according to an embodiment of the present invention.
6 illustrates a response message to a message requesting an update of a network structure according to an embodiment of the present invention.
7 illustrates a method of updating a network structure according to another embodiment of the present invention.
8 illustrates a message requesting a search for a terminal having a hop number of 2 or more with a base station according to an embodiment of the present invention.
9 illustrates a response message to a message requesting a search for a terminal having a hop number of 2 or more with a base station according to an embodiment of the present invention.
10A and 10B illustrate a method in which a base station determines an optimal path and updates a network based on the determination result according to an embodiment of the present invention.
11 transmits a message including information on route setting according to an embodiment of the present invention.
12 illustrates an apparatus for updating a network structure of a base station according to an embodiment of the present invention.
13 illustrates an apparatus for updating a network structure of a terminal 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. In the following description and the accompanying drawings, substantially the same components are denoted by the same reference numerals, and redundant description will be omitted. In addition, in describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

1 illustrates an OFDMA / TDD system according to an embodiment of the present invention.

Referring to FIG. 1, in the OFDMA / TDD system according to an embodiment of the present invention, a base station 100 and a plurality of mobile terminals 110 to 150 configure one network as shown. The base station 100 and the terminals 110 to 150 exchange a message with each other using a control link slot and an ad-hoc link slot to periodically configure and manage a network.

The base station 100 continuously collects information on link quality of the UEs using control link slots and ad hoc link slots, and searches for an optimal path for data transmission based on the collected information. Accordingly, the relay link slot and the data transmission link slot are allocated to each terminal accordingly. Slots allocated in the transmission frame according to TDD will be described later in detail with reference to FIG. 2.

2 illustrates a structure of a TDD transmission frame for multihop communication in an OFDMA / TDD system according to an embodiment of the present invention.

2, one transmission frame includes a control link slot, a plurality of relay link slots, an ad hoc link slot, and a data transmission link slot.

Control link slots and ad hoc link slots are used for searching for optimal paths and updating topology. The base station 100 transmits information for maintaining time synchronization between the base station and the terminal through a control link slot, and periodically transmits messages necessary for network structure and operation to the terminals.

The terminals included in the network may transmit and receive messages to each other through the ad hoc link slot without passing through the base station 100. The exchange of messages measures the quality of the link between the terminals, and transmits information on the quality of the link generated as a result of the measurement to the base station 100. Information about the measured link quality is transmitted through the ad hoc link slot, so that the base station 100 can update the network structure by setting an optimal path. The quality of a link may be measured based on a signal to noise ratio (SNR) of messages transmitted and received by terminals.

The preamble of the control link slot is used for time synchronization between the base station 100 and the terminal. The terminal receiving the preamble of the control link slot synchronizes the time of the base station 100 and the time of the terminal based on the information of the control link slot.

The preamble of the ad hoc link slot includes a message that each terminal transmits to the base station 100 in response to the preamble of the control link slot. The base station 100 identifies a terminal transmitting an ad hoc link preamble using a unique identifier assigned to each terminal, analyzes a round trip time (RTT), measures a distance from the corresponding terminal, and reads / rack time ( lead / lag time).

The relay link slot is used by a base station and a terminal having multiple hops, that is, two or more hops, to transmit data to the relay terminal. The relay terminal refers to a terminal that receives data from another terminal and transmits the received data to another terminal or a base station. As shown in FIG. 2, the relay link slot includes a plurality of slots having the same frequency band and different time bands, and are allocated to each of terminals connected in multi-hop with the base station. A plurality of relay link slots may be allocated to one terminal.

After searching for an optimal path for multi-hop communication, the base station allocates a relay link slot to each terminal and notifies the relay link slot allocation result through the control link slot. For example, some terminals 110 to 130 of FIG. 1 have a hop number of 1 with a base station, and some terminals 140 and 150 have a hop number of 2 with a base station. Different relay link slots may be allocated to the terminals 140 and 150.

The data transmission link slot is used to transmit data to the base station 100 by terminals 110 to 130 having a hop number of 1 with the base station. As illustrated in FIG. 2, the data transmission link slot may include a plurality of lower slots having the same time band but different frequency bands. After determining the optimal network structure, the base station notifies the terminals 110 to 130 of the number of hops with the base station 1 through the control link slot information about the allocation result of the data transmission link slot.

For example, in FIG. 1, data transmission link slot # 1 is allocated to terminal 1 110, data transmission link slot # 2 is assigned to terminal 2 120, and data transmission link slot # 3 is assigned to terminal 3 130. Can be assigned. In this case, when the terminal 1 110 has data to transmit to the base station, the terminal 1 110 transmits data through the data transmission link slot # 1. In addition, if the terminal 1 (110) is a relay terminal of the terminal 4 (140), the terminal 4 (140) receives data relayed through one of the relay link slot from step 4 (140), and transmits the received data It transmits to the base station 100 through the link slot # 1.

3 illustrates a method of updating a network structure according to an embodiment of the present invention.

Referring to FIG. 3, the base station 100 forms a network with terminals included in the area 102 of the base station 100, that is, terminals 110 and 120 having a hop number of 1 with the base station 100. . As described above, a network is formed by transmitting and receiving a message for updating the network through the control link slot and the ad hoc link slot.

In step 310, the base station 100 transmits a message requesting the update of the network through the control link slot. The message for requesting the update of the network structure will be described later in detail with reference to FIG. 5.

In operation 320, the terminal 1110 transmits a message including information on the quality of at least one link connected to the terminal 1110 in response to the message received in operation 310. The terminal 1 110 measures the quality of the link between the terminal 1 110 and other terminals through an ad hoc link slot, and transmits a message including information on the quality of the link generated according to the measurement result. To transmit. A message including information on the quality of a link will be described later in detail with reference to FIG. 6.

For example, in the network structure shown in FIG. 1, the terminal 1 110 measures the link quality with the terminal 2 120, the terminal 3 130, and the terminal 4 140 three times, and generates a measurement result. Information about the quality of the link is transmitted to the base station 100. It is possible to ensure a better quality of service (QoS) by communicating with the base station 110 via the terminal 2 120 and the terminal 3 130 than the terminal 1 110 communicates directly with the base station 100. There may be cases. Therefore, the information about the link quality between the terminal 1 (110) and the terminal 2 (120) and the information about the link quality between the terminal 1 (110) and the terminal 3 (130) also need to be transmitted to the base station (100).

The base station 100 is based on the information on the quality of the link of the terminal 1 (110) received in step 320 and the quality of the link between the base station 100 and the terminal 1 (110) measured by the base station 100 itself. Based on the determination of the bidirectional connection state between the base station 100 and the terminal 1 (110), and stores the determination result.

In step 330, the base station 100 transmits a message requesting the update of the network structure to the terminal 2 120, which is another hop number 1 terminal, through the control link slot.

In operation 340, the terminal 2 120 transmits a message including information on the quality of at least one link connected to the terminal 1 110 to the base station 100 in response to the message received in operation 330.

For example, in the network structure shown in FIG. 1, the terminal 2 120 measures the link quality with the terminal 1 110 and transmits information on the quality of the link generated as a result of the measurement to the base station 100.

The base station 100 repeats the process of transmitting a message requesting the update of the network structure as in steps 310 to 340 and receiving a message including information on the link quality as a response for all terminals having a hop number of 1. The connection state with all hops having a hop number of 1 is determined.

4 illustrates a transmission frame for transmitting and receiving information for updating a network structure according to an embodiment of the present invention.

Referring to FIG. 4, in step 310, a message transmitted from the base station 100 to the terminal 1 110 may be transmitted through the control link slot 410 of the first transmission frame 400. In addition, the message transmitted from the terminal 1 110 to the base station 100 in step 320 may be transmitted through the ad hoc link slot 420 of the same transmission frame 400.

Also, in step 330, the message transmitted from the base station 100 to the terminal 2 120 is transmitted through the control link slot 430 of the second transmission frame 402. The message transmitted to 100 may be transmitted through the ad hoc link slot 440 of the same transmission frame 402.

Since the control link slot and the ad hoc link slot are slots through which messages are transmitted and received for network update and operation, messages can be transmitted and received by channel coding using a method that is more robust to errors than the relay link slot and data link slot for data transmission and reception. Can be. Therefore, even when the communication environment is degraded, the network structure can be updated and operated.

5 illustrates a message requesting an update of a network structure according to an embodiment of the present invention.

Referring to FIG. 5, in steps 310 and 330, a message for requesting an update of a network transmitted from the base station 100 to the terminals 110 and 120 includes an identifier (S-ID) of the node that generated the message and a message. It includes an identifier (D-ID) of the receiving node, a serial number (Seq) of the message, and a type of the message. In FIG. 3, an identifier (S-ID) of a node generating a message is an identifier of the base station 100, and an identifier (D-ID) of a node receiving a message is an identifier of terminals 110 and 120. The number (Seq) is to prevent the message from being duplicated, and the type of the message is binary information to indicate that the current message is a message for requesting an update of the network Reserve is to check an error of the message or Reserved part to expand.

6 illustrates a response message to a message requesting an update of a network structure according to an embodiment of the present invention.

Referring to FIG. 6, in steps 320 and 340, the response messages transmitted by the terminals 110 and 120 to the base station 100 may include an identifier (S-ID) of the node that generated the message, an identifier of the node that receives the message ( D-ID), message serial number (Seq), message type (Type), number of information about link quality (ListSize), status of terminal transmitting message (Sts), set of information about link quality ( From ID, ToID and LQI) and the position of the terminal for transmitting the message.

In FIG. 3, an identifier (S-ID) of a node generating a message is an identifier of terminals 110 and 120, and an identifier (D-ID) of a node receiving a message is an identifier of a base station 100. The serial number Seq of the message is an identifier for preventing duplication of the message, and the type of the message is binary information for indicating that the current message is a response to the message requesting to update the network structure.

The set of information on link quality (FromID, ToID, and LQI) represents two terminals whose link quality is measured by the terminal 1 110 or the terminal 2 120 and the result of the measurement. For example, in the case of the terminal 1 110 of FIG. 1, the link quality may be measured between the terminal 2 120, the terminal 3 130, and the terminal 4 140. In this case, the first set of information on the link quality is the identifier (ID) of the terminal 1 (110), the identifier (ToID) of the terminal 2 (120) and the measured terminal 1 (110) and the terminal 2 (120) The link quality information (LQI) may be included, and the second link quality information may include an identifier (FromID) of the terminal 1 (110), an identifier (ToID) of the terminal 3 (13), and the measured terminal 1 (110). ) And information about the link quality between the terminal 3 (130) (LQI). In the same manner, a set of information on a plurality of link quality may be included in a message transmitted by the terminals 110 and 120 to the base station 100 in steps 330 and 340.

The link quality information (LQI) may include information about the quantized link quality, and when the link quality is divided into plural classes such as 'Good', 'Fair', 'Poor', and 'Bad', Binary information corresponding to each class may be included.

The number of information about the link quality (ListSize) represents the number of the above-described set of information about the link quality, the state (Sts) of the terminal for transmitting a message is the state of the terminal 1 (110) or terminal (120) For example, off, standby, on). The position of the terminal transmitting the message may be Global Positioning System (GPS) information of the terminal 1 110 or the terminal 2 120 transmitting the message.

7 illustrates a method of updating a network structure according to another embodiment of the present invention.

Referring to FIG. 7, the base station 100 uses the terminal 1 110 to form a network with the terminal 3 130 existing outside the region 102 of the base station 100. A message for updating the network is transmitted and received based on the relay of the terminal 1 (110) to form a network.

In step 710, the base station 100 transmits a message to the terminal 1 (110) requesting to search for the terminal 3 (130) having two or more hops with the base station (100). Since the number of hops 2 or more, the terminal 3 (130) exists outside the region 102 of the base station 100, the base station 100 can not directly transmit a message requesting the update of the network structure. Therefore, the base station 100 requests the terminal 1 (110) to search for the terminal 3 (130) to deliver information on the link quality of the terminal 3 (130). Message transmission in step 710 may be performed through the control link slot of the transmission frame as in step 310 of FIG. The message transmitted from the base station 100 to the terminal 1 110 in step 710 will be described later in detail with reference to FIG. 8.

In step 720, the terminal 1110 transmits a message requesting the update of the network structure to the terminal 3130 according to the message requesting to search for the terminal 3130 received in step 710. A message for requesting the update of the network structure may be transmitted to the terminal 3 130 included in the area 112 of the terminal 1 110. In operation 720, the message for requesting the update of the network structure may be the same as the message illustrated in FIG. 5.

The message transmission in step 720 may be performed through the control link slot of the transmission frame similarly to step 710. The slot used by the terminal 1 110 to transmit a message to the terminal 3 130 in step 720 may be the same slot as the control link slot used by the base station 100 to transmit a message to the terminal 1 110 in step 710. have. In other words, the search request message from the base station 100 to the terminal 1110 and the search request message from the terminal 1110 to the terminal 3130 may be transmitted together in the same control link slot of one transmission frame.

In addition, the message of step 720 may be transmitted in a transport frame different from the transport frame in which the message is transmitted in step 710. For example, in step 710, the terminal 1 110 transmits a message to the terminal 3 130 through the control link slot of the next transmission frame of the transmission frame used when the base station 100 transmits the message to the terminal 1110. Can be.

In step 730, the terminal 3 (130) sends a message to the terminal 1 (110) containing information on the quality of the link connected to the terminal 3 (130) in response to the message requesting the update of the network structure received in step 720 send. The message described above with reference to FIG. 6 may be transmitted to the terminal 1110.

A message containing information about the quality of the link may be sent over the ad hoc link slot. In addition, in step 720, the terminal 1110 may be transmitted through an ad hoc link slot of the same transmission frame used when transmitting a message requesting the update of the network structure.

In step 740, terminal 1 (110) searches for terminal 3 (130) in step 710 based on a message including information on the quality of the link connected to terminal 3 (130) received from terminal 3 (130) in step 730. Send a response message to the message requesting to be done. In step 730, a response message including information on the quality of the link between the terminal 3 130 and other terminals included in the message received is transmitted. A message transmitted from the terminal 1 110 to the base station 100 in step 740 will be described later in detail with reference to FIG. 9.

In operation 740, the message transmitted from the terminal 1 110 to the base station 100 may be transmitted through an ad hoc link slot. In addition, in step 730, the terminal 3 (130) may be transmitted through an ad hoc link slot of the same or next transmission frame used when transmitting a message to the terminal 1 (110).

The base station 100 is based on the information about the quality of the link of the terminal 3 (130) received in step 740 and the quality of the link between the base station 100 and the terminal 1 (110) measured by the base station 100 itself. Based on the determination of the connection state of the base station 100 and the terminal 1 (110) and the connection state of the terminal 1 (110) and the terminal 3 (130), and stores the determination result.

In step 750, the base station 100 transmits a message to the terminal 2 120 requesting to search for the terminal 3 130 having a hop count of 2 or more with the base station 100 in step 710. Although it corresponds to step 710, it is different from requesting to search for the terminal 3 (130) to the terminal 2 (120) rather than the terminal 1 (110).

In the example illustrated in FIG. 7, the terminal 3 130 is included only in the region 112 of the terminal 1 110, but the terminal 3 130 is out of the region 102 of the base station 100, and the terminal 1 ( It may be included in both the region 112 of the 110 and the region 122 of the terminal 2 (120). In this case, it is necessary to determine whether it is optimal to relay data through the terminal 1 (110) or relay the data through the terminal 2 (120). Accordingly, the base station 100 transmits a message requesting the search for the terminal 3 130 to all the terminals 110 and 120 having a hop number of 1 or less. As in step 710, a message requesting to search for the terminal 3 (130) through a control link slot of a transmission frame may be transmitted.

In step 760, the terminal 2 120 transmits a message requesting the update of the network structure to the terminals included in its area 122. Corresponds to step 720.

However, since the terminal 3 130 does not exist in the area 122 of the terminal 2 120, the terminal 2 120 transmits a message indicating that the terminal 3 130 has not been searched in step 770. To transmit.

8 illustrates a message requesting a search for a terminal having a hop number of 2 or more with a base station according to an embodiment of the present invention.

Referring to FIG. 8, in step 710, the message transmitted from the base station 100 to the terminal 1 110 may include an identifier (S-ID) of the node generating the message, an identifier (D-ID) of the node receiving the message, The serial number of the message (Seq), the type of the message (Type), the number of relay nodes (RylNo) relaying the terminal having a hop count of two or more base stations, the identifier of the relay nodes (RID # 1, RID # 2, ... ) And an identifier (OID) of the node to be searched. S-ID, D-ID, Seq and Type are the same as described above with reference to FIG.

The number of relay nodes RylNo refers to the number of relay terminals for relaying terminals not included in the area 102 of the base station 100. In FIG. 7, since the node relaying terminal 3 130 is one terminal 1 110, the number of relay nodes RylNo is 1, and the identifiers of the relay nodes RID # 1, RID # 2, ...) Also includes only the identifier of the terminal 1 (110). The identifier (OID) of the node to be searched is the identifier of the terminal 3 (130).

FIG. 7 illustrates a case in which one relay terminal is one terminal 1110, but two or more relay terminals may be used in multi-hop communication. Therefore, the number of relay nodes (RylNo) and the identifiers (RID # 1, RID # 2, ...) of all the relay nodes may be included in the message requesting the search for the terminal communicating in multi-hop with the base station 100. .

9 illustrates a response message to a message requesting a search for a terminal having a hop number of 2 or more with a base station according to an embodiment of the present invention.

Referring to FIG. 9, in step 740, the response message transmitted from the terminal 1 110 to the base station 100 includes an identifier (S-ID) of the node that generated the message, and an identifier (D-ID) of the node receiving the message. , Message serial number (Seq), message type (Type), the number of information about the link quality (ListSize), the status of the terminal transmitting the message (Sts), the set of information about the link quality (From ID, ToID And LQI), a position (Position) of the terminal transmitting the message, the number of relay nodes (RlyNo), and the identifiers (RID # 1, RID # 2) of the relay node.

The difference from the message shown in FIG. 6 is that the number of relay nodes (RlyNo) and the identifiers of the relay nodes (RID # 1, RID # 2) are included, which has been described above with reference to FIG.

In addition, the message shown in FIG. 9 includes information on the positions (Position # 1, Position # 2, ...) of the plurality of terminals, and the position of the terminal having two or more hops with the base station to be searched is Of course, because the information on the location of the relay terminal is included in the message.

10A and 10B illustrate a method in which a base station determines an optimal path and updates a network based on the determination result according to an embodiment of the present invention.

Referring to FIG. 10A, the base station 100 is a terminal based on information on a link quality received from terminals 110 and 120 having a hop number of 1 and a terminal 130 having a hop number of 2 or more with the base station 100. Determine the quality of the links between them. As shown in FIG. 10A, the quality of the link between the terminal 1 110 and the base station 100, the quality of the link between the terminal 2 120 and the base station 110, and the terminal 2 120 and the terminal 3 130. It is determined that the quality of the link between the 'Good', the quality of the link between the terminal 1 (110) and the terminal 2 (120) is 'Fair', the terminal 1 (110) and the terminal 3 (130) It may be determined that the quality of the link between them is 'Poor'.

The base station 100 updates the network structure based on the quality of the link between the terminals determined as shown in FIG. 10A. As a result of the update, the network structure may be set as shown in FIG. 10B. The network structure is set so that the link between the terminal 1 110 and the terminal 2 120 and the link between the terminal 1 110 and the terminal 3 130 are not used.

11 transmits a message including information on route setting according to an embodiment of the present invention.

When the network structure is updated and configured as shown in FIG. 10B, the base station 100 transmits a message including information on the updated network structure to the terminals. Information on the network path to the base station 100 may be transmitted to each terminal. Information on a network path may be transmitted through a control link slot of a transmission frame.

FIG. 11 shows a message including information on a network path to the base station 100 to each terminal transmitted by the base station 100. Referring to FIG. 11, the message transmitted to each terminal by the base station 100 includes an identifier (S-ID) of the node that generated the message, an identifier (D-ID) of the node that receives the message, and a serial number of the message ( Seq), the type of message (Type), the number of links on the network path (R-Len), the number of relay nodes (RylNo) for relaying terminals with more than 2 hops from the base station, the identifier of the relay nodes (RID # 1, RID # 2, ...) and the identifier of the start node and end node of each link (FromID # 1, ToID # 1, FromID # 2, ToID # 2, ...).

The number of links (R-Len) on the network path means the number of links included in the network path from the base station 100 to the terminal. In the example shown in FIG. 10B, only one link is included in the network paths to the terminal 1 110 and the terminal 2 120, and two links are included in the network path to the terminal 3 120. Information on the number of links is included in the message as the number of links (R-Len) on the network path.

The number of relay nodes RylNo and the identifiers RID # 1 and RID # 2 of the relay nodes have been described above with reference to FIG. 8. Since the terminals having a hop number of 1 and the base station 110 have no relay terminal, the number of relay nodes RylNo is '0' and there is no identifier of the relay node.

Identifiers (FromID # 1, ToID # 1, FromID # 2, ToID # 2, ...) of the start node and the end node of each link include identifiers of terminals for specifically specifying a link included in a network path. do. Referring to the network path of the terminal 3 130 shown in FIG. 10B as an example, it has been described above that the link to the terminal 3 130 includes two links. At this time, in order to specifically specify the two links 'FromID # 1' is the identifier of the base station, 'ToID # 1' is the identifier of the terminal 2 (120), 'FromID # 2' is the identifier of the terminal 2 (120), 'ToID # 2' includes information about the identifier of the terminal 3 (130).

12 illustrates an apparatus for updating a network structure of a base station according to an embodiment of the present invention.

12, an apparatus 1200 for updating a network structure of a base station according to an embodiment of the present invention includes an update request unit 1210, a response receiver 1220, and an update unit 1230.

The update request unit 1210 transmits a message requesting the update of the network structure to the terminals included in the area 102 of the base station 100. In response to the message requesting the update, each of the terminals included in the area 102 of the base station 100 transmits a response message including information on the quality of the link connected thereto, and the response receiver 1220 Receive this response message. The updater 1230 updates the network structure based on the received response message and the information on the link quality with the terminals measured by the base station 100 and updates the network path information according to the updated network structure. Send to the terminal.

The update request unit 1210 also receives a message requesting to search for a terminal located outside the region 102 of the base station 100, that is, a terminal having a hop count of two or more with the base station 100. May be transmitted to a relay terminal located at The relay terminal receiving the search request transmits a message requesting the update of the network structure to the terminal having two or more hops included in its own area, and receives the information on the link quality received in response to the transmission. To be sent). The updater 1230 updates the network structure based on the information on the link quality of the terminal having two or more hops received from the response receiver 1220, and transmits information on the network path to the terminal having two or more hops through the relay terminal. send.

13 illustrates an apparatus for updating a network structure of a terminal according to an embodiment of the present invention.

Referring to FIG. 13, an apparatus 1300 for updating a network structure of a terminal according to an embodiment of the present invention includes a request transceiver 1310 and a response transceiver 1320.

The request transmission / reception unit 1310 receives a message requesting an update of the network structure from the base station 100, and the response transmission / reception unit 1320 receives information on the quality of at least one link connected to the terminal in response thereto. 100).

The request transmitting and receiving unit 1310 also receives a message requesting a search for a terminal having a hop number of 2 or more from the base station 100, and sends a message requesting the update of the network structure to a terminal having a hop number of 2 or more based on the received message. send. In response to the search request, the response transceiver 1320 receives information on link quality of a terminal having a hop number of 2 or more, and transmits the received information to the base station 100.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited to the above-described embodiments, which can be modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications will fall within the scope of the invention. In addition, the system according to the present invention can be embodied as computer readable codes on a computer readable recording medium.

For example, a base station and a terminal according to an exemplary embodiment of the present invention include a bus coupled to respective units of the apparatus as shown in FIGS. 12 and 13, and at least one processor coupled to the bus. can do. It may also include a memory coupled to the bus for storing instructions, received messages or generated messages and coupled to at least one processor for performing instructions as described above.

The computer-readable recording medium also includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device and the like. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

Claims (11)

A method for updating a network topology by a base station in an OFDMA / TDD system,
Transmitting a first message requesting an update of the network structure to a predetermined terminal having a hop count of 1 through the first slot of a transmission frame;
Receiving a second message from the predetermined terminal, the second message including information on a quality of a link between the predetermined terminal and another terminal through a second slot of a transmission frame; And
Updating the network structure based on the second message,
The transmission frame may include a first slot, a second slot, terminals included in the network to which the base station belongs, a third slot for relaying data of another terminal having a hop number of 2 or more from the base station, and terminals included in the network. And a fourth slot for transmitting data to the base station. The method of claim 1, wherein the first slot is
And the base station is a slot allocated by time division in a transmission frame to transmit information for operating the network to terminals included in the network. The method of claim 1, wherein the second slot is
And the terminals included in the network are slots allocated by time division in a transmission frame to transmit and receive a predetermined message without passing through the base station. The method of claim 1, wherein the fourth slot is
And a plurality of lower slots allocated in frequency division in the fourth slot to simultaneously transmit data through different frequency bands. The method of claim 1, wherein updating the network structure based on the second message comprises:
Repeating the transmission of the first message and the reception of the second message for all terminals having a hop number of 1 with the base station; And
And updating the network structure based on a plurality of second messages received from all terminals included in the network. A method for updating a network topology by a base station in an OFDMA / TDD system,
Transmitting a first message requesting discovery of a second terminal having a hop number of two or more with the base station through a first slot of a transmission frame to a first terminal having a hop number of one with the base station;
Receiving a second message from the first terminal, the second message including information about a quality of a link between the second terminal and another terminal through a second slot of a transmission frame; And
Updating the network structure based on the second message,
The transmission frame includes the first slot, the second slot, a third slot included in the network to which at least one terminal included in the network to which the base station belongs, relays data of another terminal having a hop count of 2 or more from the base station and the network. At least one terminal comprises a fourth slot for transmitting data to the base station. The method of claim 6, wherein the first terminal
A third message for requesting the update of the network structure is transmitted to the second terminal through the first slot of the transmission frame based on the first message, and the second slot of the transmission frame is sent in response to the third message. And receiving a fourth message including information on a quality of a link between the second terminal and another terminal through the network. 8. The method of claim 6 and 7, wherein the first slot is
And the base station is a slot allocated by time division in a transmission frame to transmit information for operating the network to terminals included in the network. 8. The method of claim 6 and 7, wherein the second slot is
And the terminals included in the network are slots allocated by time division in a transmission frame to transmit and receive a predetermined message without passing through the base station. 8. The method of claim 6 and 7, wherein the fourth slot is
And a plurality of lower slots allocated in frequency division in the fourth slot to simultaneously transmit data through different frequency bands. A computer-readable recording medium having recorded thereon a program for executing the method of claim 1.

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