Method for transmitting a frame at a high rate in a wireless local area network

• US 20050030930A1
• Filed: 07/26/2004
• Published: 02/10/2005
• Est. Priority Date: 07/26/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jang, Kyung-Hun, Hwang, Hyo-Sun, Cho, Jin-Youn, Seo, Chang-Woo, Chang, Jin-Bong
• Granted Patent: US 7,489,668 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/24 Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

A method for transmitting data at a high rate in a wireless LAN is provided. A wireless access point requests reliable node information from a wireless terminal having a transfer rate equal to or less than a predetermined transfer rate if data to be transmitted to the terminal occurs. The terminal produces a frame containing information related to reliable nodes that can communicate with the terminal and information of greatest transfer rates between the reliable nodes and the terminal, and transmits the frame to the access point. The access point selects an optimal relay node from the reliable nodes, based on the greatest transfer rates between the reliable nodes and the access point and transfer rates between the reliable nodes and the terminal, and determines if a relay gain exists when using the optimal node. If the relay gain exists, the access point performs relay transmission to the terminal; otherwise, it performs direct transmission to it.

Claims

1. A method for transmitting data in a wireless local area network, the method comprising the steps of:

a) requesting, from a wireless terminal by a wireless access point, information related to reliable nodes having a transfer rate less than a predetermined threshold if data to be transmitted to the wireless terminal occurs in the wireless access point;

b) producing, by the wireless terminal, a reliable node information frame containing both information related to reliable nodes capable of communicating with the wireless terminal over a wireless channel and information related to greatest allowable transfer rates between the reliable nodes and the wireless terminal, and transmitting the reliable node information frame from the wireless terminal to the wireless access point;

c) determining, by the wireless access point, an optimal relay node selected from the reliable nodes, based on the greatest allowable transfer rates between the reliable nodes and the wireless access point and based on greatest allowable transfer rates between the reliable nodes and the wireless terminal, and determining if a relay gain exists; and

d) performing relay transmission from the wireless access point to the wireless terminal if the relay gain exists, and performing direct transmission from the wireless access point to the wireless terminal if no relay gain exists.

2. The method according to claim 1, wherein step c) further includes the steps of:

comparing a transfer rate of direct transmission to the wireless terminal with an actual transfer rate of relay transmission to the wireless terminal via the optimal relay node; and

determining if the relay gain exists, based on the transfer rate comparison.

3. The method according to claim 1, further comprising the step of:

e) analyzing, by a wireless terminal, a header of a data frame if the wireless terminal receives the data frame, to determine if the received data frame is a relay data frame, and deleting a header and a flag for relaying from the received data frame if the received data frame is a relay data frame, and then transmitting the data frame to a corresponding destination node.

4. The method according to claim 1, wherein if a relay node relays a frame to be transmitted during the relay transmission, the wireless access point assumes that the wireless access point has received a response signal from the relay node.

5. The method according to claim 1, wherein step c) further includes the steps of:

selecting a reliable node providing a highest transfer rate from the wireless access point to a destination terminal from among the reliable nodes, based on greatest allowable transfer rates between the wireless access point and the reliable nodes and based on greatest allowable transfer rates from the reliable nodes to the destination terminal; and

determining the selected reliable node to be the optimal relay node.

6. A method for transmitting a data frame by a wireless access point in a wireless local area network including the wireless access point and a plurality of wireless terminals, said wireless access point capable of transmitting a data frame to the plurality of wireless terminals over wireless channels, the method comprising the steps of:

a) requesting information related to reliable nodes from a wireless terminal having a transfer rate less than a predetermined threshold if data to be transmitted to the wireless terminal occurs;

b) determining, upon receipt of a reliable node information frame as a response signal from the wireless terminal, an optimal relay node from among the reliable nodes, based on greatest allowable transfer rates between the reliable nodes and the wireless access point, and based on greatest allowable transfer rates between the reliable nodes and the wireless terminal;

c) comparing relay transmission to the wireless terminal via the optimal relay node with direct transmission to the wireless terminal to determine if a relay gain exists; and

d) performing relay transmission to the wireless terminal if the relay gain exists, and performing direct transmission to the wireless terminal if no relay gain exists.

7. The method according to claim 6, wherein step b) further includes the steps of:

calculating greatest allowable transfer rates between the wireless access point and the reliable nodes included in the received reliable node information frame;

selecting a reliable node providing a greatest transfer rate from the wireless access point to a destination terminal from among the reliable nodes, based on the calculated greatest allowable transfer rates and based on the greatest allowable transfer rates from the reliable nodes to the destination terminal; and

determining the selected reliable node to be the optimal relay node.

8. The method according to claim 6, wherein step c) includes the steps of:

comparing a transfer rate of a direct transmission to the wireless terminal with an actual transfer rate of a relay transmission to the wireless terminal via the optimal relay node; and

determining if the relay gain exists, based on the transfer rate comparison.

9. The method according to claim 6, wherein if a relay node relays a frame to be transmitted during the relay transmission, the wireless access point assumes that the wireless access point has received a response signal from the relay node.

10. A method for receiving a data frame by a wireless terminal in a wireless local area network including a wireless access point and a plurality of wireless terminals, said wireless access point capable of transmitting a data frame to the plurality of wireless terminals over wireless channels, the method comprising the steps of:

a) providing upon receipt of a reliable node information request from the wireless access point, a response signal containing information related to all nodes capable of communicating with the wireless terminal and information related to greatest allowable transfer rates between the wireless terminal and the nodes, each of all the nodes being associated with a corresponding one of said greatest allowable transfer rates; and

b) receiving a data frame from one of the reliable nodes or from the wireless access point, producing a response signal to the data frame, and providing the response signal to the wireless access point.

11. A method for relaying a data frame by a wireless terminal in a wireless local area network including a wireless access point and a plurality of wireless terminals, said wireless access point capable of transmitting a data frame to the plurality of wireless terminals over wireless channels, the method comprising the steps of:

a) analyzing upon receipt of a data frame from the wireless access point, a header of the received data frame to determine if the received data frame is a relay frame; and

b) deleting a relay header and a relay flag from the received data frame if the received data frame is a relay frame, and transmitting the data frame to a destination address.