Ad-hoc network wireless communication system and method thereof

• US 20050089057A1
• Filed: 09/01/2004
• Published: 04/28/2005
• Est. Priority Date: 10/27/2003
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Won-soo, Kim, Il-whan, Kang, Chung-gu
• Granted Patent: US 7,391,789 B2
• Time in Patent Office: Days
• US Class Current: 370/445
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

An ad-hoc network wireless communication system transmits data packets from one hop to another hop in a relay manner, and includes a transmitting node for transmitting a RTS message in order to transmit the data packets, and a receiving node, existing in a next hop of the transmitting node, for transmitting a CTS message in response to the RTS message transmitted from the transmitting node. The receiving node transmits the CTS message to another receiving node successively connected to the receiving node in response to the transmitted CTS message, and the transmitting node transmits the data packets to the receiving node in the case that the CTS message transmitted by the receiving node of the next hop is received over a predetermined number of times. The ad-hoc network wireless communication system can maximize the communication efficiency in a multi-hop network with its complexity minimized by extending a MAC protocol based on a IEEE 802.11 DCF to a reservation-based MAC in the multi-hop network.

Claims

1. An ad-hoc network wireless communication system that transmits data packets from one hop to another hop in a relay manner, the communication system comprising:

a transmitting node operable to transmit a request-to-send (RTS) message in order to transmit the data packets; and

a receiving node, existing in a next hop of the transmitting node, operable to transmit a clear-to-send (CTS) message in response to the RTS message transmitted from the transmitting node;

wherein the receiving node transmits the CTS message to another receiving node successively connected to the receiving node in response to the transmitted CTS message, and the transmitting node transmits the data packets to the receiving node in the case that the CTS message transmitted by the receiving node of the next hop is received over a predetermined number of times.

2. The communication system as claimed in claim 1, wherein the receiving node comprises:

a receiving unit operable to receive at least one of the RTS message and the CTS message;

a message conversion unit operable to convert the received CTS message into the RTS message; and

a transmitting unit operable to transmit the CTS message in response to at least one of the received RTS message and the converted RTS message.

3. The communication system as claimed in claim 2, wherein the receiving node existing in the next hop of the transmitting node transmits the CTS message after a DCF-inter-frame-space (DIFS) time in response to the converted RTS message if the CTS message is received from another receiving node existing in the next hop.

4. The communication system as claimed in claim 3, wherein the receiving node further comprises a piggyback unit operable to piggyback an acknowledgement (ACK) message to the received data packet;

wherein the transmitting unit transmits the data packet to which the ACK message is piggybacked by the piggyback unit to another receiving node.

5. The communication system as claimed in claim 4, wherein the receiving node and the transmitting node have the same construction.

6. The communication system as claimed in claim 5, wherein the transmitting node includes a counter operable to count a number of receptions of the CTS message received from the receiving node.

7. The communication system as claimed in claim 6, wherein the transmitting node transmits the data packet to the receiving node if the number of receptions of the CTS message counted by the counter is 2.

8. A wireless communication method for an ad-hoc network wireless communication system that transmits data packets from one hop to another hop in a relay manner, the communication method including:

(a) a transmitting node transmitting a request-to-send (RTS) message to a receiving node existing in a next hop in order to transmit the data packets;

(b) the receiving node transmitting a clear-to-send (CTS) message in response to the transmitted RTS message;

(c) the receiving node transmitting the CTS message to another receiving node successively connected to the receiving node in response to the transmitted CTS message; and

(d) the transmitting node transmitting the data packets to the receiving node of the next hop in the case that the transmitting node receives the CTS message transmitted by the receiving node of the next hop over a predetermined number of times.

9. The communication method as claimed in claim 8, further comprising:

(e) the receiving node receiving at least one of the RTS message and the CTS message; and

(f) the receiving node converting the received CTS message into the RTS message;

wherein the CTS message is transmitted in response to at least one of the received RTS message and the converted RTS message.

10. The communication method as claimed in claim 9, wherein the receiving node existing in the next hop of the transmitting node transmits the CTS message after a DCF-inter-frame-space (DIFS) time in response to the converted RTS message if the CTS message is received from another receiving node existing in the next hop.

11. The communication method as claimed in claim 10, further comprising:

(g) the receiving node piggybacking an acknowledgement (ACK) message to the received data packet; and

(h) transmitting the data packet to which the ACK message is piggybacked at step (g) to another receiving node.

12. The communication method as claimed in claim 11, wherein the receiving node and the transmitting node have the same construction.

13. The communication method as claimed in claim 12, further comprising (i) the transmitting node counting a number of receptions of the CTS message received from the receiving node.

14. The communication method as claimed in claim 13, wherein the transmitting node transmits the data packet to the receiving node if the number of receptions of the CTS message counted at step (i) is 2.