Apparatus for multicast transmissions in wireless local area networks

• US 8,737,281 B2
• Filed: 06/27/2008
• Issued: 05/27/2014
• Est. Priority Date: 06/18/2008
• Status: Expired due to Fees

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Liu, Hang, Mandrekar, Ishan, Wu, Minquan, Perumanam, Ramkumar, Mathur, Saurabh
• Primary Examiner(s): GHOWRWAL, OMAR J
• Application Number:
  US12/737,173
• Publication Number:
  US 20110080977A1
• Time in Patent Office: 2,160 Days
• Field of Search: 370/310, 370/312, 370/351, 370/389, 370/390, 370/392, 370/393, 370/229, 370/235, 370/236, 370/241, 370/252
• US Class Current: 370/312
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 74/006 in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Message formats and apparatus are described that serve to reserve access to a communication medium in a multi-cast system. A first message, a multicast request-to-send message, includes a duration field having information representing the reserved time for a communication medium, a multicast receiver address field, a multicast transmitter address field, a field that identifies the number of slots for a clear-to-send response, and a field that identifies the number slots for a not-clear-to-send response. A second message includes a duration field, and a multicast receive address field. The second message has a format that can be used as one of a clear-to-send message in response to a multicast request-to-send message, a cancel-clear-to-send message that cancels a data transmission after the clear-to-send message is sent, and a not-clear-to-send message in response to the multicast request-to-send message.

Claims

1. An apparatus that receives a multicast digital message while operating on a channel in a wireless communication medium, the apparatus comprising:

a receiver receiving the multicast digital message from a transmitter on the channel in the medium, the multicast digital message having a format comprising;

a duration field specifying a time period for which the transmitter desires to reserve the medium;

a multicast receiver address field specifying a multicast medium access control (“

MAC”

) address of the apparatus;

a multicast transmitter address field specifying a MAC address of the transmitter of the multicast digital message;

a multicast clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a positive reply signal; and

a multicast not clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a negative reply signal; and

a transmitter transmitting either a clear to send message or a not clear to send message by utilizing the transmission time slots in a contention period to send the positive reply signal or the transmission time slots in a contention period to send the negative reply signal respectively in response to the received multicast digital message; and

a processor that resets a network allocation vector of the apparatus when no transmission on the channel is received in a time interval T between times T1 and T2, wherein the time T1 occurs at a time comprising a sum of;

a time interval for receiving the multicast digital message;

a time interval for transmission of the clear to send message multiplied by a number of clear to send message slots;

a time interval for transmission of the not clear to send message multiplied by a number of not clear to send message slots; and

a time interval for interframe guard intervals; and

wherein the time T2 occurs at the time T1 added to a wait time.

2. The apparatus of claim 1, wherein the multicast digital message comprises a multicast request-to-send message to reserve time in a communication medium to receive multicast data.

3. The apparatus of claim 1, wherein the multicast clear-to-send slot number field defines a number of time intervals for responding to the multicast digital message.

4. The apparatus of claim 1, wherein the multicast not-clear-to-send slot number field defines a number of time intervals for responding to the multicast digital message.

5. The apparatus of claim 1, the multicast digital message further comprising a frame control field, herein the frame control field comprises a frame type identification.

6. A non-transitory computer program storage device containing computer instructions which, when executed in an apparatus that operates on a channel in a wireless communications medium, enable processing of a multicast digital message, the mutlicast digital message having a format comprising:

a duration field specifying a time period for which a transmitter desires to reserve the medium;

a multicast receiver address field specifying a multicast medium access control (“

MAC”

) address of the apparatus;

a multicast transmitter address field specifying a multicast medium access control (“

MAC”

) address of the transmitter of the multicast message;

a multicast clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a positive reply signal; and

a multicast not-clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a negative reply signal;

wherein the apparatus responds to the received multicast digital message by transmitting on the channel either a clear to send message or a not clear to send message by utilizing the transmission time slots in a contention period to send the positive reply signal or the transmission time slots in a contention period to send the negative reply signal respectively;

wherein a network allocation vector of the apparatus is reset when no transmission on the channel is received in a time interval T between times T1 and T2, wherein the time T1 occurs at a time comprising a sum of;

a time interval for receiving the multicast digital message;

a time interval for transmission of the clear to send message multiplied by a number of clear to send message slots;

a time interval for transmission of the not clear to send message multiplied by a number of not clear to send message slots; and

a time interval for interframe guard intervals; and

wherein the time T2 occurs at the time T1 added to a wait time.

7. The storage device of claim 6, wherein the multicast digital message comprises a multicast request-to-send message to reserve time in a communication medium to receive multicast data.

8. The storage device of claim 6, wherein the multicast clear-to-send slot number field defines a number of time intervals for responding to the multicast digital message.

9. The storage device of claim 6, wherein the multicast not-clear-to-send slot number field defines a number of time intervals for responding to the multicast digital message.

10. The storage device of claim 6, the multicast digital message further comprising a frame control field, wherein the frame control field comprises a frame type identification.

11. An apparatus that receives a multicast digital message while operating on a channel in a wireless communication medium, the apparatus comprising:

a receiver receiving the multicast digital message from a transmitter on the channel in the medium, the multicast digital message having a format comprising;

a duration field specifying a time period for which the transmitter desires to reserve the medium;

a multicast receiver address field specifying a multicast medium access control (“

MAC”

) address of the apparatus;

a multicast transmitter address field specifying a MAC address of the transmitter of the multicast message;

a multicast clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a positive reply signal; and

a multicast not clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a negative reply signal; and

a processor that responds to the received multicast digital message by using a transmitter to transmit on the channel a clear to send message by utilizing the transmission time slots in a contention period to send the positive reply signal; and

wherein the processor further acts to transmit a cancel clear to send message on the channel when no transmission on the channel is received in a time interval T between times T1 and T2, wherein the time T1 occurs at a time comprising a sum of;

a time interval for receiving the multicast digital message;

a time interval for transmission of the clear to send message multiplied by a number of clear to send message slots;

a time interval for transmission of the not clear to send message multiplied by a number of not clear to send message slots; and

a time interval for interframe guard intervals; and

wherein the time T2 occurs at the time T1 added to a wait time.

12. A non-transitory computer program storage device containing computer instructions which, when executed in an apparatus that operates on a channel in a wireless communications medium, enable processing of a multicast digital message, the multicast digital message having a format comprising:

a duration field specifying a time period for which a transmitter desires to reserve the medium;

a multicast receiver address field specifying a multicast medium access control (“

MAC”

) address of the apparatus;

a multicast transmitter address field specifying a multicast medium access control (“

MAC”

) address of the transmitter of the multicast digital message;

a multicast clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a positive reply signal;

a multicast not clear-to-send slot number field specifying transmission time slots in a contention period useful by the apparatus to send a negative reply signal; and

wherein the apparatus responds to the received multicast digital message by transmitting on the channel a clear to send message by utilizing the transmission time slots in a contention period to send the positive reply signal;

wherein a cancel clear to send message is transmitted on the channel when no transmission on the channel is received in a time interval T between times T1 and T2, wherein the time T1 occurs at a time comprising a sum of;

a time interval for receiving the multicast digital message;

a time interval for transmission of the clear to send message multiplied by a number of clear to send message slots;

a time interval for transmission of the not clear to send message multiplied by a number of not clear to send message slots; and

a time interval for interframe guard intervals; and

wherein the time T2 occurs at the time T1 added to a wait time.