Collision mitigation for multicast transmission in wireless local area networks

• US 8,553,548 B2
• Filed: 06/23/2008
• Issued: 10/08/2013
• Est. Priority Date: 06/23/2008
• Status: Expired due to Fees

• Current Assignee: Magnolia Licensing LLC (IP Edge LLC)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Liu, Hang, Mandrekar, Ishan, Perumanam, Ramkumar, Mathur, Saurabh, Wu, Mingquan
• Primary Examiner(s): GHOWRWAL, OMAR J
• Application Number:
  US12/736,846
• Publication Number:
  US 20110064013A1
• Time in Patent Office: 1,933 Days
• Field of Search: 370229-230, 370/231, 370/235, 370/236, 370/310, 370/312, 370/314, 370/351, 370/389, 370/390, 370/392, 370/241, 370/252
• US Class Current: 370/235
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 12/1863 comprising mechanisms for improved reliability, e.g. status reports arrangements for detecting or preventing errors by carrying supervisory signal the return channel H04L1/16
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

A method and apparatus are described including determining if a communications medium is idle; determining a time interval for a reservation of said communications medium; multicasting a message for reserving said communications medium; receiving responses to said message for reserving said communications medium; and determining if a number of said received responses compared to an expected number of responses exceeds a value; performing one of initiating pending frame exchanges and multicasting data or management frames during said time interval for said reservation of said communications medium if said comparison exceeds said value; repeating said first determining act if said comparison does not exceed said value. Also described are a method and apparatus including receiving a message for a reservation of a communications medium; determining if said message specifies a receiver of the message in a list of receivers from which a response is requested; determining if said communications medium is idle; determining a time period in which to transmit said response responsive to an order in said list, wherein said list of receivers is one of a reply list of receiver addresses and a combination of a bitmap control field and a partial virtual bitmap; and transmitting said response to said message responsive to said second determination.

Claims

1. A method, said method comprising:

receiving a message for a reservation of a communications medium;

a first determining, performed by a device, wherein determining that said message specifies a receiver of the message in a list of receivers from which a response is requested;

a second determining, performed by the device, wherein determining that said communications medium is idle;

a third determining, wherein determining a time period in which to transmit said response responsive to an order in said list, wherein said list of receivers is a combination of a bitmap control field and a partial virtual bitmap, said bitmap control field containing a bitmap offset corresponding to a base association identifier divided by 16 and wherein each bit in said partial virtual bitmap corresponds to a specific receiver, and when bit i in said partial virtual bitmap is set then a receiver with said bitmap offset multiplied by 16+i is requested to respond to said message for reserving said communications medium; and

transmitting said response responsive to said third determining.

2. The method according to claim 1, further comprising determining a time interval for said reservation of said communications medium, wherein said time interval is determined by setting a value of a duration field to a value of a previous duration field less an elapsed time and a guard time interval, said value of said previous duration field having been specified in said message for reserving said communications medium.

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

a fourth determining, wherein determining whether to transmit a cancellation message; and

transmitting a cancellation message responsive to said fourth determining.

4. The method according to claim 1, wherein said communications medium is a wireless channel.

5. The method according to claim 1, wherein said method is performed via a wireless network.

6. An apparatus, comprising:

at least one central processing unit;

a random access memory;

one or more input/output interfaces; and

further comprising;

means for receiving a message for a reservation of a communications medium;

first means for determining that said message specifies a receiver in a list of receivers from which a response is requested;

second means for determining that said communications medium is idle;

third means for determining a time period in which to transmit said response responsive to an order in said list, wherein said list of receivers is a combination of a bitmap control field and a partial virtual bitmap, said bitmap control field containing a bitmap offset corresponding to a base association identifier divided by 16 and wherein each bit in said partial virtual bitmap corresponds to a specific receiver, and when bit i in said partial virtual bitmap is set then a receiver with said bitmap offset multiplied by 16+i is requested to respond to said message for reserving said communications medium; and

means for transmitting said response responsive to said third determining means.

7. The apparatus according to claim 6, further comprising means for determining a time interval for said reservation of said communications medium, wherein said time interval is determined by setting a value of a duration field to a value of a previous duration field less an elapsed time and a guard time interval, said value of said previous duration field having been specified in said message for reserving said communications medium.

8. The apparatus according to claim 6, further comprising:

fourth means for determining whether to transmit a cancellation message; and

means for transmitting a cancellation message responsive to said fourth means for determining.

9. The apparatus according to claim 6, wherein said communications medium is a wireless channel.

10. The apparatus according to claim 6, wherein said apparatus operates via a wireless network.