KR20120113496A - Method of transmission between one hop links in wireless mesh network and mesh node supporting the same - Google Patents

Abstract

The present invention relates to a method of transmitting a wireless mesh network, the method comprising: receiving a data from a first mesh node by a second mesh node, and the first mesh node by the second mesh node; And transmitting a reception response to the data, wherein the data is a Node Identifier (NID) indicating a source node that generates the data or a destination node that is the destination of the data; Polling that requires the reception response. Therefore, in multi-hop transmission, delay problems due to end-to-end ARQ retransmission can be minimized, and transmission reliability can be improved.

Description

Method of transmission between one hop links in wireless mesh network and mesh node supporting the same}

The present invention relates to a wireless mesh network, and more particularly, a method of transmitting one hop link between multi-hop data and a mesh node supporting the same. It is about.

A wireless mesh network is a network that supports direct communication between a plurality of mesh nodes having a relay function. In a wireless mesh network, a mesh node may have a separate communication path from each of surrounding mesh nodes. Such a wireless mesh network has advantages such as flexibility in network construction, reliability by a bypass path, and power consumption reduction due to a shortening of a communication distance. In addition, since large data can be delivered quickly and securely, it is widely used in large-scale venues and the military.

Meanwhile, in a conventional wireless mesh network, when transmitting Medium Access Control (MAC) Protocol Data Unit (PDU) through multiple hops, ARQ (Automatic Repeat Request) after negotiation through DSA (Dynamic Service Addition) process for each service flow Determines whether to send), and performs this. However, when end-to-end ARQ transmission is performed through multiple hops, a long time is required when ARQ feedback information is transmitted from a destination node to a source node. In addition, when a loss occurs during data transmission in the intermediate hop, a serious delay problem occurs when the start node recognizes an error of the packet and retransmits the packet.

Also, since ARQ operates only on a service flow that performs a DSA process, in general, basic service flows (services such as real-time commands) and unicast management messages that do not perform a DSA process are performed. In addition, there is a need for a method for improving reliability other than ARQ in the MAC stage.

An object of the present invention is to provide a 1-hop link transmission method and a mesh node supporting the same in multi-hop data transmission in a wireless mesh network.

Another technical problem of the present invention is to provide a transmission method for an error packet between 1-hop links when a MAC PDU is transmitted through multiple hops in a wireless mesh network, and a mesh node supporting the same.

Another technical problem of the present invention is to provide a dynamic service flow that requires a DSA process and a basic service flow that does not require a DSA process in order to improve reliability at a MAC side, in addition to an ARQ function applied only to a dynamic service flow. A method of transmitting a 1-hop link of a cast management message and a mesh node supporting the same are provided.

In one aspect, a method of transmitting a wireless mesh network is provided. The transmission method includes the steps of receiving a data from a first mesh node by a second mesh node, and transmitting a reception response for the data to the first mesh node by the second mesh node. The data includes a node identifier (NID) indicating a source node that generates the data or a destination node that is the destination of the data, and polling that requires the reception response.

The transmission method may further include the second mesh node receiving the data from the first mesh node again.

The data may be a Medium Access Control Protocol Data Unit (MAC PDU) including a header, an extended header and a payload, and the header may include the NID and the polling.

The data may be a control connection message or a transport connection message.

The reception response may include an extension header including a sequence number of the successfully received MAC PDU.

In another aspect, a method of transmitting a wireless mesh network is provided. The transmission method includes transmitting a data by a first mesh node to a second mesh node, and receiving a reception response to the data from the second mesh node by the first mesh node. The data includes a node identifier (NID) indicating a source node that generates the data or a destination node that is the destination of the data, and polling that requires the reception response.

In another aspect, a mesh node of a wireless mesh network is provided. The mesh node includes a receiving unit receiving data from a starting node, a processor generating a receiving response for the data, and a transmitting unit transmitting the receiving response to the starting node, wherein the data is the source node. Or a Node Identifier (NID) indicating a destination node that is the destination of the data, and a polling requesting the reception response.

In another aspect, a mesh node of a wireless mesh network is provided. The mesh node includes a transmitter for transmitting data to an object node, and a receiver for receiving a response to the data from the object node, wherein the data is a source node or the object node generating the data. It includes a node identifier (NID) indicating a destination node and polling for requesting the reception response.

In multi-hop transmission, delay problems caused by end-to-end ARQ retransmission can be minimized.

It is possible to improve the reliability of multi-hop transmission for flows that do not support ARQ.

When ARQ is not used, reliability of 1-hop link transmission can be improved.

1 is a diagram illustrating the structure of a wireless mesh network system.
2 is an operation example of the dynamic service flow and the basic service flow of the present invention.
3 is an operation example of the unicast management message of the present invention.
4 is an operation example of a control connection message of the present invention.
5 is an operation example of a transport connection message of the present invention.
6 is a block diagram of a mesh node in which an embodiment of the present invention is implemented.

1 is a diagram illustrating the structure of a wireless mesh network system.

As shown in FIG. 1, the wireless mesh network 100 is a network that supports direct communication between a plurality of mesh nodes 101, 102, 103, 104, and 105 having a relay function. In a wireless mesh network, a mesh node may have a separate communication path from each of surrounding mesh nodes.

In a wireless mesh network, a source node refers to a mesh node that first generates data and transmits the data to a destination node, and the destination node refers to a final destination of data generated at the start node. The relay node relays data between the start node and the destination node.

In multi-hop data transmission, if the mesh node 102 is the starting node and the mesh node 105 is the destination node in FIG. 1, that is, the data is the starting node 102, the mesh node 103. ), The mesh node 104 and the mesh node 104 become relay nodes if transmitted through the path of the mesh node 104 and the destination node 105. Specifically, the mesh node 103 becomes a first relay node, and the mesh node 104 becomes a second relay node. In addition, between the start node 102 and the first relay node 103, the first relay node 103 and the second relay node 104, the second relay node 104 and the destination node 105 are 'one hop'. (one hop) '

Meanwhile, in a conventional wireless mesh network, when transmitting Medium Access Control (MAC) Protocol Data Unit (PDU) through multiple hops, ARQ (Automatic Repeat Request) after negotiation through DSA (Dynamic Service Addition) process for each service flow Determines whether to send), and performs this. However, when end-to-end ARQ transmission is performed through multiple hops, a long time is required when ARQ feedback information is transmitted from a destination node to a source node. In addition, when a loss occurs during data transmission in the intermediate hop, a serious delay problem occurs when the start node recognizes an error of the packet and retransmits the packet.

Also, since ARQ operates only on a service flow that performs a DSA process, in general, basic service flows (services such as real-time commands) and unicast management messages that do not perform a DSA process are performed. In addition, there is a need for a method for improving reliability other than ARQ in the MAC stage.

Table 1 shows an example of a modified MAC header of the present invention. The message name or message format is described in section 16.2.2.1.1 of IEEE P802.16m / D12 “Part 16: Air Interface for Broadband Wireless Access Systems” (hereinafter referred to as 802.16m), published February 17, 2011. Based on.

Syntax Size (bit) Notes Advanced Generic MAC Header (AGMH) () { CID 12 bits Connection Identifier NID 12 bits Node Identifier EH 1 bit Extended header group presence indicator Length 14 bits This field indicates the length in bytes of MAC PDU including the AGMH and extended header if present. Polling 1 bit }

The Advanced Generic MAC Header (AGMH) includes a CID field, a NID field, an EH field, a length field, and a polling field.

The Connection Identifier (CID) field indicates an address for identifying / identifying a connection mapped to a required service flow between each peer on the MAC sublayer.

The Node Identifier (NID) field indicates the start node ID for the Dynamic Service Flow and the Broadcast MAC PDU, and indicates the basic service flow and the unicast management MAC PDU of the unicast management MAC PDU. In this case, the destination node ID is indicated.

The Extended Header (EH) field is an indicator indicating the existence of an extended header group. When set to '1', it indicates that an extension header group exists after the AGMG.

When using the Hop-by-hop MAC PDU Retransmission Query (HRQ), an acknowledgment is not required if the polling field is set to '0'. On the other hand, when the polling field is set to '1', an acknowledgment is required when a MAC message is received. Furthermore, when the MAC message is a control connection message, the reception response is transmitted in the MCAEH field, and in the case of the transport connection message, the reception response is transmitted in the MTAEH field. More detailed operation will be described.

2 is an operation example of the dynamic service flow and the basic service flow of the present invention.

In a one-hop link transmission from mesh node A to mesh node B, mesh node A meshes MAC PDU 210 including AGMH 211, Extended Header (EH) 212 and Payload 213. Send to Node B. Meanwhile, as shown in Table 1, the HRQ function may be used by using a polling field of 1 bit in the AGMH 211 of the MAC PDU 210. If set to '0' does not use the HRQ function, it does not need to send a response, and if set to '1' transmits the response (220).

In the case of dynamic service flows (VoIP, real-time traffic, etc.), it is possible to determine whether to use HRQ through DSA negotiation. If the user decides to use the HRQ function, the polling field is set to '1' for the corresponding service flow to generate the MAC PDU 210 including the negotiated CID. Accordingly, the mesh node A increases and transmits a sequence number (SN) value in the MAC PDU 210 for each negotiated CID, that is, for each service flow, and the mesh node B uses the corresponding sequence number value to transmit the MAC. Confirm that the PDU 210 is successfully received. The sequence number is in extension header 212 following AGMH 211.

In the basic service flow, a dedicated CID is used when generating MAC PDU in mesh node A. If the mesh node A wants to use the HRQ function for the corresponding service flow, the MAC node ADU generates the MAC PDU 210 by using the corresponding CID value and setting the polling field to '1'. Mesh node A uses one dedicated CID and destination NID for several basic service flows, and sequentially increases and transmits a sequence number value for MAC PDUs 210 of the corresponding service flows. The mesh node B checks the reception of the MAC PDUs 210 using the corresponding sequence number value and feeds back the mesh node A with the retransmission.

Table 2 shows an example of the MAC Control Extended Header (MCEH) format of the present invention. In case of MCEH, the standard and name of 802.16m are the same, but the operation is different.

Syntax Size (bit) Notes MAC Control Extended Header (MCEH) () { Type 4 bits Extended header type = 0b0010 (MCEH Type) FC 2 bits Fragmentation control SN 10 bits Payload sequence number. The SN value increments by one (modulo 1024) sequentially. }

The MCEH includes a Type field, an FC field, and an SN field.

When the fragmentation control (FC) field is set to '00', the first byte of data in the MAC PDU payload is the first byte of the MAC Service Data Unit (SDU), and the last byte of data in the MAC PDU payload is the last byte of the MAC SDU. byte. If set to '01', the first byte of data in the MAC PDU payload is the first byte of the MAC SDU, and the last byte of data in the MAC PDU payload is not the last byte of the MAC SDU. When set to '10', the first byte of data in the MAC PDU payload is not the first byte of the MAC SDU, and the last byte of data in the MAC PDU payload is the last byte of the MAC SDU. When set to '11', the first byte of data in the MAC PDU payload is not the first byte of the MAC SDU, and the last byte of data in the MAC PDU payload is not the last byte of the MAC SDU.

The SN (Sequence Number) field is a payload sequence number. The SN field value is continuously increased by one.

3 is an operation example of the unicast management message of the present invention.

In the 1-hop transmission from mesh node A to mesh node B, mesh node A transmits MAC PDU 310 including AGMH 311, MCEH 312 and payload 313 to mesh node B. Meanwhile, as shown in Table 1, the HRQ function may be used using a 1-bit polling field in the AGMH 311 of the MAC PDU 310. If set to '0' does not use the HRQ function, it does not need to send a response, and if set to '1' transmits the response (320).

In the case of unicast management messages, the same CID is used as in the basic service flow. If the HRQ function is to be used, the MAC PDU 310 is generated by using the dedicated CID value and setting the polling field to '1'. In addition, the SN field value existing in the MCEH 312 is sequentially increased and transmitted. Since mesh node A must include MCEH 312 for unicast management messages, mesh node B uses the SN field and FC field values to determine whether to retransmit for 1 hop for multiple management messages. You can give feedback.

Broadcast messages do not use the HRQ feature.

Meanwhile, a timer (HR, HRQ_ERROR_DETECTION_TIMER) that the mesh node waits for a response to a reception response is received as a system parameter when registering a network.

In addition, the response response feedback supports both a cumulative ACK scheme and a selective ACK MAP scheme.

4 is an operation example of a control connection message of the present invention.

On one-hop link transmission from mesh node A to mesh node B, mesh node A transmits MAC PDU 410 including AGMH 411, MCEH 412, and payload 413 to mesh node B. If mesh node A sends MAC PDU 410 with the polling field of AGMH 411 set to '1', mesh node B sends MCAEH 422 to MAC PDU 410 with the polling field set to '1'. ) And pass it to mesh node A.

If the mesh node B receives the control connection message 410 in which the polling field in the AGMH 411 is set to '1', that is, when using the HRQ function, the SN field value in the MCEH 412 of the control connection message is received. Using the MCAEH 422 immediately responds according to the feedback method determined in the flag field in the MAC Control ACK Extended Header (MCAEH).

Table 3 shows an example of the MCAEH format of the present invention.

Syntax Size (bit) Notes MAC Control ACK Extended Header (MCAEH) () { Type 4 bits Extended header type = 0b0011 (MCAEH) Flag 1 bit 0 = Cumulative ACK
1 = Selective ACK MAP existence ACK_SN 10 bits Indicates the sequence number of an MAC PDU block.
FLAG = 0, indicates MAC PDU blocks up to and including the sequence number in the ACK_SN field have been received successfully.
FLAG = 1, indicates MAC PDU blocks less than the sequence number in the ACK_SN field have been received successfully.
It also indicates the sequence number of PDU block whose ACK or NACK information is indicated by the MSB of Selective ACK MAP. If (Flag == 0) { Reserved 1 bit } else If (Flag == 1) { NSI 1 bit NACK Suspended Indicator
0 = Bit marked '0' in the following Selective ACK MAP represents a HRQ PDU block NACK
1 = Bit marked '0' in the following Selective ACK MAP represents that HRQ PDU block NACK decision is suspended
(ie, HRQ_ERROR_DETECTION_TIMER is running for corresponding HRQ PDU block). Selective ACK MAP variable Each bit represents ACK or NACK or NACK suspended of corresponding HRQ PDU block.
'0' is NACK if NSI equals zero
'0' is NACK suspended if NSI equals one
'1' is ACK.
MSB of the First Selective ACK MAP represents ACK or NACK information of a PDU block identified by the sequence numbers in the ACK_SN field.
Contiguous bits after MSB of the First Selective ACK MAP represents ACK or NACK information of contiguous PDU blocks following the PDU block identified by the sequence number in the ACK_SN field.
(Maximum size of Selective ACK MAP is equal to size of HOP_RETX_WINODW_SIZE) } // If (Flag == 0) Padding variable For byte alignment. }

When the reception response is transmitted in the cumulative ACK method, it means that the ACK_SN has been successfully received. When the reception response is transmitted in the selective ACK MAP method, it means that the MAC PDUs before the ACK_SN are successfully received. In addition, ACK and NACK information for the MAC PDU corresponding to ACK_SN is indicated in the MSB of the Selective ACK MAP. In the selection ACK MAP method, when the NSI field is set to '0', a value of '0' in the selection ACK MAP field means NACK, and when the NSI field is set to '1', '0' in the selection ACK MAP field. The value of means NACK suspended. That is, it means that the NACK determination is pending for the MAC PDU of the sequence number which has not yet expired HRQ_ERROR_DETECTION_TIMER.

5 is an operation example of a transport connection message of the present invention.

When transmitting between 1-hop links from mesh node A to mesh node B, mesh node A is AGMH (511), MAC SDU Fragmentation Extended Header (FEH) / MAC SDU Packing Extended Header (PEH) 512, and payload (513). The MAC PDU 510 including the transmits to the mesh node B. If mesh node A sends MAC PDU 510 with the polling field of AGMH 511 set to '1', mesh node B sends a MTAEH 522 for MAC PDU 510 with the polling field set to '1'. ) And pass it to mesh node A.

If the mesh node B receives the transport connection message 510 whose polling field in the AGMH 511 is set to '1', that is, when using the HRQ function, the SN in the FEH / PEH 512 of the transport connection message is received. Using the field value, it immediately responds through the MTAEH 522 according to the feedback method determined in the Flag Field in the MAC Traffic ACK Extended Header (MTAEH) 522.

Table 4 shows an example of the MTAEH format of the present invention.

Syntax Size (bit) Notes MAC Traffic ACK Extended Header (MTAEH) () { Type 4 bits Extended header type = 0b0100 (MTAEH Type) Flag 1 bit 0 = Cumulative ACK
1 = Selective ACK MAP existence ACK_SN 10 bits Indicates the sequence number of an MAC PDU block.
FLAG = 0, indicates MAC PDU blocks up to and including the sequence number in the ACK_SN field have been received successfully.
FLAG = 1, indicates MAC PDU blocks less than the sequence number in the ACK_SN field have been received successfully.
It also indicates the sequence number of PDU block whose ACK or NACK information is indicated by the MSB of Selective ACK MAP. If (Flag == 0) { Reserved 1 bit } else If (Flag == 1) { NSI 1 bit NACK Suspended Indicator
0 = Bit marked '0' in the following Selective ACK MAP represents a HRQ PDU block NACK
1 = Bit marked '0' in the following Selective ACK MAP represents that HRQ PDU block NACK decision is suspended
(ie, HRQ_ERROR_DETECTION_TIMER is running for corresponding HRQ PDU block). Selective ACK MAP variable Each bit represents ACK or NACK or NACK suspended of corresponding HRQ PDU block.
'0' is NACK if NSI equals zero
'0' is NACK suspended if NSI equals one
'1' is ACK.
MSB of the First Selective ACK MAP represents ACK or NACK information of a PDU block identified by the sequence numbers in the ACK_SN field.
Contiguous bits after MSB of the First Selective ACK MAP represents ACK or NACK information of contiguous PDU blocks following the PDU block identified by the sequence number in the ACK_SN field.
(Maximum size of Selective ACK MAP is equal to size of HOP_RETX_WINODW_SIZE) } // If (Flag == 0) { Padding variable For byte alignment. }

When the reception response is transmitted in the cumulative ACK method, it means that the ACK_SN has been successfully received. When the reception response is transmitted in the selective ACK MAP method, it means that the MAC PDUs before the ACK_SN are successfully received. In addition, ACK and NACK information for the MAC PDU corresponding to ACK_SN is indicated in the MSB of the Selective ACK MAP. In the selection ACK MAP method, when the NSI field is set to '0', a value of '0' in the selection ACK MAP field means NACK, and when the NSI field is set to '1', '0' in the selection ACK MAP field. The value of means NACK suspended. That is, it means that the NACK determination is pending for the MAC PDU of the sequence number which has not yet expired HRQ_ERROR_DETECTION_TIMER.

6 is a block diagram of a mesh node in which an embodiment of the present invention is implemented.

The mesh nodes 700 and 800 include receivers 701 and 801, processors 702 and 802, and transmitters 703 and 803.

The transmitter 703 of the first mesh node 700 transmits data to the second mesh node 800. An AGMH including a CID field, an NID field and a polling field, an MAC PDU including an extension header and a payload including an FC field and an SN field are examples of the data.

The receiver 801 of the second mesh node 800 receives the data from the first mesh node 700. The processor 802 of the second mesh node 800 is connected to the receiver 801 to generate a response to the data. The transmitter 803 of the second mesh node 800 is connected to the processor 802 and transmits the reception response to the first mesh node 700.

The receiving unit 701 of the first mesh node 700 receives the reception response from the second mesh node 800. The processor 702 of the first mesh node 700 is connected to the receiver 701 to process a message indicating that the reception response is normally received or not received. The transmitter 703 of the first mesh node 700 is connected to the process 702 to retransmit the data to the second mesh node 800 when the message indicates that the reception response has not been received.

Claims (15)

In the transmission method of a wireless mesh network,
Receiving, by a second mesh node, data from the first mesh node; And
Sending, by the second mesh node, a response to the data to the first mesh node;
The data may include a node identifier (NID) indicating a source node that generates the data or a destination node that is the destination of the data, and polling that requires the reception response. Transmission method. The method of claim 1,
And the second mesh node re-receives the data from the first mesh node. The method of claim 1,
And the data is a MAC PDU (Medium Access Control Protocol Data Unit) including a header, an extended header and a payload. The method of claim 3, wherein
And the header includes the NID and the polling. The method of claim 1,
And the data is a control connection message or a transport connection message. The method of claim 1,
The reception response includes an extension header including a sequence number of successfully received MAC PDUs. In the mesh node of a wireless mesh network,
A receiver for receiving data from a start node;
A processor for generating a response to the data; And
Including a transmitter for transmitting the reception response to the start node,
The data node includes a node identifier (NID) indicating the source node or a destination node that is the destination of the data, and a polling requesting the reception response. . 8. The method of claim 7,
And the data is a MAC PDU including a header including the NID and the poll, an extension header and a payload. 8. The method of claim 7,
And wherein the receive response includes an extension header including a sequence number of a successfully received MAC PDU. In the transmission method of a wireless mesh network,
Transmitting, by a first mesh node, data to a second mesh node; And
The first mesh node receiving a response to the data from the second mesh node;
The data may include a node identifier (NID) indicating a source node that generates the data or a destination node that is the destination of the data, and polling that requires the reception response. Transmission method. The method of claim 10,
And retransmitting the data by the first mesh node to the second mesh node. The method of claim 10,
And the data is a MAC PDU including the header including the NID and the poll, an extension header and a payload. The method of claim 10,
The reception response includes an extension header including a sequence number of successfully received MAC PDUs. In the mesh node of a wireless mesh network,
A transmitter for transmitting data to the destination node; And
Receiving unit for receiving a response to the data from the destination node,
The data node includes a node node (NID) indicating a source node or the destination node that generates the data, and a polling node that requests the reception response. . The method of claim 14,
And wherein the receive response includes an extension header including a sequence number of a successfully received MAC PDU.

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