Systems and Methods For Reliable Broadcast and Multicast Transmission Over Wireless Local Area Network

• US 20080225811A1
• Filed: 03/11/2008
• Published: 09/18/2008
• Est. Priority Date: 03/12/2007
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Wentink, Maarten Menzo
• Granted Patent: US 8,165,154 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1671 the supervisory signal being transmitted together with control information
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Broadcast and multicast (BM) systems have not been reliable in the wireless local area networks. Higher bandwidth and more reliable BM transmissions are necessitated by video and audio applications. A class of BM reliable frames is transmitted at a higher rate. The access point performs some rudimentary collision avoidance to enhance reliability, and individual stations are given the ability to send feedback to the access point regarding the quality of the transmission.

Claims

1. A method for broadcasting a reliable broadcast/multicast (RBM) burst comprising:

marking each frame in the RBM burst to identify each frame as reliable;

transmitting a message to a station for collision avoidance;

receiving the response from the station if available; and

transmitting each frame in the RBM burst separated by a short interframe space (SIFS) if a response was received.

2. The method of claim 1, wherein the message is a request to send frame and the response is a clear to send frame.

3. The method of claim 1, wherein the message is a NULL frame and the response is an acknowledgement frame.

4. The method of claim 1, wherein the message is a data frame and the response is an acknowledgement frame.

5. The method of claim 1, wherein transmitting each frame is transmitted at a higher physical layer (PHY) rate than a basic PHY rate.

6. The method of claim 5, wherein transmitting each frame is terminated by transmitting a NULL frame with a more data bit not set at the basic PHY rate.

7. The method of claim 5, wherein the higher PHY rate is adjusted based on receiving a RBM feedback frame.

8. The method of claim 7, wherein the RBM feedback frame comprises a packet error rate (PER).

9. The method of claim 7, wherein the RBM feedback frame comprises a received signal strength indication (RSSI);

10. The method of claim 7, wherein the RBM feedback frame comprises report a suggested PHY rate.

11. The method of claim 7, wherein the RBM feedback frame comprises a modulation coding scheme (MCS).

12. The method of claim 1 further comprising:

if the response is not received, waiting a backoff period; and

if the response is not received, retransmitting the message.

13. The method of claim 1 wherein the transmitting each frame occurs after the transmission of a delivery traffic indication map (DTIM) beacon frame.

14. The method of claim 1, wherein the transmitting each frame begins after a set interval after a target beacon transmission time (TBTT), wherein the set interval is equal to an RBM transmit opportunity (TXOP) start interval plus a non-negative multiple of an RMB TXOP service interval.

15. The method of claim 14, wherein the RBM TXOP service interval and the RBM TXOP start interval are announced in a beacon frame or transmitted in a probe response.

16. An access point configured for transmitting an RBM burst comprising a first frame, said access point comprising:

a processor;

a wireless network interface device; and

a memory comprising instructions;

said instructions causing the processor

to mark each frame in the RBM burst to identify each frame as reliable;

to cause the wireless network interface device to transmit a message to a station for collision avoidance;

to cause the wireless network interface device to receive through a response from the station if available; and

to cause the wireless network interface device to transmit each frame in the reliable broadcast or multicast burst separated by a SIFS if a response was received.

17. The access point of claim 16, wherein the message is a request to send frame and the response is a clear to send frame.

18. The access point of claim 16, wherein the message is a NULL frame or a data frame and the response is an acknowledgement frame.

19. The access point of claim 16, wherein the instructions cause the processor to transmit through the wireless network interface device each frame on the broadcast or multicast burst at a higher PHY rate than a basic PHY rate and to terminate transmission of the broadcast or multicast burst by causing the wireless network interface to transmit a NULL frame with a more data bit not set at the basic PHY rate.

20. The access point of claim 19, wherein the higher PHY rate is adjusted based on receiving a reliable broadcast/multicast feedback frame.

21. The access point of claim 20, wherein the RBM feedback frame comprises a PER, an RSSI, a suggested PHY rate, an MCS, or a combination thereof.

22. The access point of claim 16, wherein if no response is received, the instructions cause the processor to wait a backoff period and to cause the wireless network interface device to retransmit the message.

23. The access point of claim 16, wherein the processor causes the wireless network interface device to transmit the first frame of the RBM burst after the transmission of a DTIM beacon frame.

24. The access point of claim 16, wherein the processor causes the wireless network interface device to transmit the first frame of the RBM burst after a set interval after a TBTT, wherein the set interval is equal to an RBM TXOP start interval plus a non-negative multiple of an RMB TXOP service interval.

25. The access point of claim 24, wherein the RBM TXOP service interval and the RBM TXOP start interval are announced in a beacon frame or transmitted in a probe response.

26. An access point configured for transmitting an RBM burst comprising:

means for marking each frame in the RBM burst to identify each frame as reliable;

means for avoiding collisions; and

means for transmitting each frame in the RBM burst separated.

27. The access point of claim 26 further comprising means for waiting a backoff period.

28. The access point of claim 26, further comprising means for adjusting a PHY rate associated with the RBM burst based on receiving a RBM feedback frame.