METHOD FOR PROTECTING DATA IN A MU-MIMO BASED WIRELESS COMMUNICATION SYSTEM

• US 20120236840A1
• Filed: 11/24/2010
• Published: 09/20/2012
• Est. Priority Date: 11/24/2009
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Kim, Yun-Joo, Lee, Jae-Seung, Lee, Sok-Kyu
• Granted Patent: US 8,861,495 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

The present invention relates to a method for protecting MU-MIMO (Multi User-Multiple Input Multiple Output) data through a multi-RTS/CTS frame exchange in a MU-MIMO based wireless communication system. The method of the present invention comprises: a process where an indicator for VHT data protection is added to an RTS frame, using the structure of an RTS/CTS frame for an existing legacy terminal during the multi RTS/CTS frame exchange; a process where an access point designates and then transmits the duration period of the RTS frame while transmitting the RTS frame; and a process where wireless terminals up to the (n-1)th terminal designate the duration period of the CTS frame as ‘0’ and send the designated duration period, while only the n-th wireless terminal designates NAV for data protection.

Claims

1. A method for protecting data transmitted from a transmitting wireless station to at least one receiving wireless station in a wireless communication system using MU-MIMO technology, comprising:

(a) transmitting a transmission request frame from the transmitting wireless station to each of the at least one receiving wireless station; and

(b) receiving a transmission approval frame from each of the at least one receiving wireless station as a response to the transmission request frame, wherein the transmission request frame comprises a VHT data marker for protecting VHT traffic.

2. The method of claim 1, wherein the transmission request frame is a RTS (Request To Send) frame, and the transmission approval frame is a CTS (Clear To Send) frame.

3. The method of claim 2, wherein the VHT data marker uses a specific field of the RTS frame for a legacy wireless station.

4. The method of claim 3, wherein the RTS frame has a duration corresponding to the sum of transmission time of the CTS frame, transmission time of a next data frame, and response time for the next data frame.

5. The method of claim 3, wherein the RTS frame has a duration corresponding to a limit value of TXOP.

6. A method for protecting data transmitted from a transmitting wireless station to receiving wireless stations as many as a natural number n (n>

1) in a wireless communication system using MU-MIMO technology, comprising;

(a) transmitting a transmission request frame from the transmitting wireless station to each of at least one receiving wireless station; and

(b) receiving a transmission approval frame from each of the at least one receiving wireless station as a response to the transmission request frame, wherein

the transmission request frame has a frame duration set for NAV setting.

7. The method of claim 6, wherein the transmission request frame transmitted to the last receiving wireless station of the plurality of receiving wireless stations has a duration different from a duration of transmission request frames to the other receiving wireless stations.

8. The method of claim 7, wherein the transmission request frames transmitted to the other receiving wireless stations than the last receiving wireless station have a duration corresponding to the sum of each IFS and transmission time of the transmission approval frames, and p1 the transmission request frame transmitted to the last receiving wireless station has a duration corresponding to the sum of transmission time of a transmission approval frame by the last receiving wireless station, transmission time of a VHT data frame, transmission time of a response frame, and IFS for each frame.

9. The method of claim 8, wherein the transmission request frame is a RTS frame, and the transmission approval frame is a CTS frame.

10. A method for protecting data transmitted from a transmitting wireless station to receiving wireless stations as many as a natural number n (n>

1) in a wireless communication system using MU-MIMO technology, comprising;

(a) transmitting a transmission request frame from the transmitting wireless station to each of a plurality of receiving wireless stations; and

(b) receiving a transmission approval frame from each of the plurality of receiving wireless stations as a response to the transmission request frame, wherein

the transmission approval frames received from the receiving wireless stations, except for the last receiving wireless station, have a duration set as ‘

0’

, and

the transmission request frame transmitted to the last receiving wireless station has a duration corresponding to the sum of transmission time of a transmission approval frame by the last receiving wireless station, transmission time of a VHT data frame, transmission time of a response frame, and IFS for each frame.

11. The method of claim 10, further comprising the phase of resetting a NAV value by the wireless stations, from which the transmission approval frames having a duration of ‘

0’

have been received.

12. The method of claim 11, wherein the transmission request frame is a RTS frame, and the transmission approval frame is a CTS frame.