Method and system for channel access control for transmission of video information over wireless channels

Abstract

A method and system for channel access control for transmission of uncompressed video information over wireless channels. A contention-free period (CFP) for high-rate and low-rate channels is divided into schedules in which one or multiple periodical channel time blocks are reserved for wireless transmission of isochronous streams.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a functional block diagram of a wireless network that implements uncompressed HD video transmission between wireless stations, according to an embodiment of the present invention.

FIG. 2 shows an example timing diagram for Time Division Duplex (TDD) scheduling applied to low-rate and high-rate wireless communication channels in FIG. 1.

FIG. 3A shows an example superframe structure for dividing a CFP for shared channel access into multiple schedule periods for transmission of video information in the network of FIG. 1, according to the present invention.

FIG. 3B shows an example superframe structure including a beam-search period, according to the present invention.

FIG. 4 shows an example superframe structure, without a beam-search period, according to the present invention.

FIG. 5 shows an example superframe structure with CFP time allocation for two streams with one data packet buffer size requirement, according to the present invention.

FIG. 6 shows an example superframe structure with CFP time allocation for two streams wherein the sender and receiver have large buffers, according to the present invention.

FIG. 7 shows an example CFP schedule information element format in a beacon frame of FIG. 1, according the present invention.

FIG. 8 shows an example format of a schedule item in FIG. 7, according to the present invention.

FIG. 9 shows an example bandwidth request command format in the network of FIG. 1, according to the present invention.

FIG. 10 shows an example format of a bandwidth request item in FIG. 9, according to the present invention.

FIG. 11 shows an example bandwidth response command format in the network of FIG. 1, according to the present invention.

FIG. 12 shows an example format for a bandwidth response item in FIG. 11, according to the present invention.

FIG. 13 shows a functional block diagram of another wireless network that implements uncompressed HD video transmission between wireless stations, according to an embodiment of the present invention.

FIG. 14 shows a flowchart of an example process for channel access control implemented in the network of FIG. 13, according to the present invention.

Claims

1. A method for communication of video information over wireless channels in a communication system including senders and receivers, comprising the steps of: packetizing video information of one or more video streams into packets for transmission over a wireless channel;controlling channel access by dividing a contention-free period (CFP) into one or more schedules, wherein each schedule includes one or more periodical channel time blocks (CTBs) reserved for transmission of isochronous streams; andtransmitting packets from a sender to a receiver during the channel time blocks.

2. The method of claim 1 wherein: controlling channel access further includes controlling channel access by dividing the CFP into channel time blocks for a high-rate channel and a low-rate channel into schedules; andtransmitting packets further includes the steps of: transmitting packets of video information from a sender to a receiver over the high-rate channel during the channel time blocks, and transmitting acknowledgment packets from the receiver to sender over the low-rate channel during the channel time blocks.

3. The method of claim 2 wherein controlling channel access further includes providing a superframe period comprising a beacon frame that provides schedule timing allocations for dividing the contention-free period (CFP) into channel time blocks.

4. The method of claim 3 wherein the superframe further comprises a contention-based control period (CBCP) for communicating control and management commands over a low-rate channel.

5. The method of claim 4 wherein no information is transmitted over a high-rate channel during a CBCP.

6. The method of claim 4 wherein the superframe further comprises a beam-search period (BSP) for searching transmission beams.

7. The method of claim 4 further comprising the steps of periodically transmitting a beacon to signal the start of a superframe period.

8. The method of claim 4 wherein the beacon specifies the start time, and length, of the CBCP and CFP in the corresponding superframe.

9. The method of claim 8 wherein the beacon specifies an allocation of channel time blocks to different senders and receivers.

10. The method of claim 9 wherein the beacon further specifies an allocation of channel time blocks to different streams.

11. The method of claim 4 wherein channel access during the CFP is based on Time Division Multiple Access (TDMA).

12. The method of claim 4 wherein each schedule comprises a series of evenly distributed CTBs with equal length, in the CFP.

13. The method of claim 4 further comprising the steps of: a sender transmitting a bandwidth request command for transmission of both isochronous streams and asynchronous data over a channel; andif sufficient bandwidth remains in the channel, then allocating a schedule in the CFP to the sender.

14. The method of claim 13 further comprising the step of allocating multiple schedules to the sender.

15. The method of claim 13 further comprising the step of the sender transmitting multiple streams to a receiver over the channel during the allocated schedule.

16. The method of claim 13 further comprising the steps of: the sender transmitting a stream to a receiver over the channel during the allocated schedule; andthe receiver transmitting an ACK to the sender during the schedule.

17. The method of claim 16 wherein during a CTB one or more packets are transmitted from the sender to the receiver, and one or more corresponding ACKs are transmitted from the receiver to the sender.

18. A system for communication of video information over wireless channels, comprising: a coordinator configured for controlling channel access by dividing a contention-free period (CFP) into one or more schedules, wherein each schedule includes one or more periodical channel time blocks (CTBs) reserved for transmission of isochronous streams; anda transmitter including a packetizer configured to place video information of one or more video streams into packets for transmission over a wireless channel, and a communication module for transmitting packets to a receiver over a high-rate channel during the channel time blocks.

19. The system of claim 18 further comprising a receiver configured for transmitting acknowledgment packets from the receiver to the transmitter during the channel time blocks over a low-rate channel.

20. The system of claim 19 wherein the coordinator is further configured to provide a superframe period comprising a beacon frame that includes schedule timing allocations for dividing the CFP into channel time blocks.

21. The system of claim 20 wherein the superframe further comprises a CBCP for communicating control and management commands over a low-rate channel.

22. The system of claim 21 wherein no information is transmitted over a high-rate channel during the CBCP.

23. The system of claim 21 wherein the superframe further comprises a BSP for searching transmission beams.

24. The system of claim 21 wherein the coordinator is further configured to periodically transmit a beacon to signal the start of a superframe period.

25. The system of claim 21 wherein the beacon specifies the start time, and length, of the CBCP and CFP in the corresponding superframe.

26. The system of claim 25 wherein the beacon specifies an allocation of channel time blocks to different senders and receivers.

27. The system of claim 26 wherein the beacon further specifies an allocation of channel time blocks to different streams.

28. The system of claim 21 wherein channel access during the CFP is based on TDMA.

29. The system of claim 21 wherein each schedule comprises a series of evenly distributed CTBs with equal length, in the CFP.

30. The system of claim 21 wherein: the transmitter is further configured to transmit a bandwidth request command for transmission of both isochronous streams and asynchronous data over a channel; andthe controller is further configured to determine if sufficient bandwidth remains in the channel, and if sufficient bandwidth remains in the channel then allocate a schedule in the CFP for transmission of both isochronous streams and asynchronous data by the transmitter over the channel.

31. The system of claim 30 wherein the coordinator is further configured to allocate multiple schedules to the transmitter.

32. The system of claim 30 wherein the transmitter is further configured to transmit multiple streams to the receiver over the channel during the allocated schedule.

33. The system of claim 30 wherein: the transmitter is further configured to transmit a stream to the receiver over the channel during the allocated schedule; andthe receiver is further configured to transmitting an ACK to the sender during the schedule.

34. The system of claim 33 wherein during a CTB, one or more packets are transmitted from the transmitter to the receiver, and one or more corresponding ACKs are transmitted from the receiver to the transmitter.

35. A coordinator for controlling communication of video information over wireless channels in a communication network, comprising: a scheduler configured to divide a contention-free period (CFP) into one or more schedules, wherein each schedule includes one or more periodical channel time blocks (CTBs) reserved for transmission of isochronous streams; anda controller configured to receive a bandwidth request, and allocate channel bandwidth based on said schedules to control channel access.

36. The coordinator of claim 35 wherein: the controller is configured to receive a bandwidth request over a low-rate channel from a wireless transmitter, and allocate channel bandwidth based on said schedules to control access to a high-rate channel by the transmitter for transmission of video information to a wireless receiver over the high-rate channel.

37. The coordinator of claim 36 wherein the scheduler is configured to provide a superframe period comprising a beacon frame that includes schedule timing allocations for dividing the CFP into channel time blocks.

38. The coordinator of claim 37 wherein the superframe further comprises a CBCP for communicating control and management commands over a low-rate channel.

39. The coordinator of claim 38 wherein no information is transmitted over a high-rate channel during the CBCP.

40. The coordinator of claim 38 wherein the superframe further comprises a BSP for searching transmission beams.

41. The coordinator of claim 38 wherein the coordinator is further configured to periodically transmit a beacon to signal the start of a superframe period.

42. The coordinator of claim 38 wherein the beacon specifies the start time, and length, of the CBCP and CFP in the corresponding superframe.

43. The coordinator of claim 42 wherein the beacon specifies an allocation of channel time blocks to different senders and receivers.

44. The coordinator of claim 43 wherein the beacon further specifies an allocation of channel time blocks to different streams.

45. The coordinator of claim 38 wherein channel access during the CFP is based on TDMA.

46. The coordinator of claim 38 wherein each schedule comprises a series of evenly distributed CTBs with equal length, in the CFP.

47. The coordinator of claim 38 wherein: the network includes a transmitter configured to transmit a bandwidth request to the coordinator for transmission of both isochronous streams and asynchronous data over a channel; andthe controller is further configured to determine if sufficient bandwidth remains in the channel, and if sufficient bandwidth remains in the channel then allocate a schedule in the CFP for transmission of both isochronous streams and asynchronous data by the transmitter over the channel.

48. The coordinator of claim 47 wherein the controller is further configured to allocate multiple schedules to the transmitter.

49. The coordinator of claim 47 wherein the transmitter is further configured to transmit multiple streams to the receiver over the channel during the allocated schedule.

50. The coordinator of claim 47 wherein the network further includes a receiver, such that the transmitter is configured to transmit a stream to the receiver over the channel during the allocated schedule, and the receiver is configured to transmit an ACK to the sender during the allocated schedule.

51. The coordinator of claim 50 wherein during a CTB, one or more packets are transmitted from the transmitter to the receiver, and one or more corresponding ACKs are transmitted from the receiver to the transmitter.