Method and system for device discovery in a wireless video area network

• US 20080095072A1
• Filed: 05/10/2007
• Published: 04/24/2008
• Est. Priority Date: 05/18/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Singh, Harkirat, Shao, Huai-Rong, Ngo, Chiu
• Granted Patent: US 8,265,657 B2
• Time in Patent Office: Days
• US Class Current: 370/254
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals

Abstract

A method and system for device discovery in a wireless network is provided. The device discovery involves directionally transmitting a data unit from a transmitting station over a channel in different directions to emulate omni-directional transmission, receiving the data unit transmissions from different directions at a receiving station, determining the quality of the transmissions received from the different directions, and detecting location information for the transmitting station relative to the receiving station based on the highest quality transmission among the transmissions received from the different directions. Further, if a channel has sufficient bandwidth to satisfy direct link communication between two stations, then during a direct link set-up stage, the two stations conduct a probing message exchange using omni-direction transmission, and upon successful probing, obtain communication link status information and set proper communication configurations for the two stations based on the communication link status information.

Claims

1. A method for device discovery in a wireless network, comprising the steps of:

directionally transmitting a data unit from a transmitting station over a channel in different directions to emulate omni-directional transmission;

receiving the data unit transmissions from different directions at a receiving station;

determining the quality of the transmissions received from the different directions; and

detecting location information for the transmitting station relative to the receiving station based on the highest quality transmission among the transmissions received from the different directions.

2. The method of claim 1 wherein the location information comprises a location vector including N elements corresponding to directional transmissions of a data unit in N different directions, wherein each vector element describes the signal quality of the transmission along a corresponding one of the N directions.

3. The method of claim 1 wherein detecting location information further includes determining the direction of the transmitting station relative to the receiving station, as location information.

4. The method of claim 1 wherein said channel comprises a low rate channel implementing orthogonal frequency division multiplexing (OFDM), providing both omni-directional and beam-steered modes.

5. The method of claim 4 wherein directionally transmitting comprises transmitting a data unit in different directions by beam-steering transmission of the data unit in said different directions.

6. The method of claim 4 wherein transmission data rates for the channel range from about 2.5 Mb/s to about 10 Mb/s for the omni-directional mode, and about 20 Mb/s to about 40 Mb/s for the beam-steered mode.

7. The method of claim 4 wherein the channel is in the about 57.2 GHz to about 65.8 GHz frequency band.

8. The method of claim 1 wherein the data unit comprises a frame.

9. The method of claim 1 further comprising the step of:

the receiving station maintaining location information for the location information for each associated station.

10. The method of claim 9 further comprising the step of:

each associated station maintaining location information for itself and other stations identified in beacons broadcast by a coordinator station.

11. The method of claim 2 further comprising the steps of:

a coordinator station periodically transmitting a beacon in omni-directional emulation mode, wherein N copies of the beacon are directionally transmitted in N different directions;

a receiving station measuring and comparing the signal quality for copies of the beacon received from the coordinator in different directions, to determine a new location vector for the coordinator station; and

determining a distance between the new location vector and an existing location vector.

12. The method of claim 11 further comprising the steps of:

if the distance is larger than a pre-defined threshold, then the receiving station transmitting a location updating control frame to the coordinator station; and

the coordinator station updating the location information for the receiving station maintained by the coordinator.

13. The method of claim 12 further comprising the step of:

the coordinator announcing the new location information for the receiving station in a next beacon transmission from the coordinator.

14. The method of claim 2 further comprising the steps of:

a coordinator station maintaining location information for associated stations in the network relative to the coordinator;

a first associated station sending a location query request control frame to the coordinator for location information of one or more other associated stations;

the coordinator providing location information of said one or more other associated stations to the first associated station; and

the first associated station determining location information of a second device relative to the first associated device using;

the location information of the first associated device relative to the coordinator, and the location information of the second associated device relative to the coordinator.

15. The method of claim 2 further comprising the steps of:

a coordinator station maintaining location information for associated stations in the network relative to the coordinator;

the coordinator periodically transmitting said location information in a beacon; and

an associated receiving station using a reduced PHY preamble and reduced payload in a frame transmission to the coordinator based on the corresponding location information.

16. The method of claim 15 further comprising the steps of:

a coordinator station maintaining location information for associated stations in the network relative to the coordinator;

a multicast source station in a multicast group obtaining location information of stations in the multicast group by performing location query exchanges with the coordinator station;

determining the location information of other stations in relation to the multicast source; and

the multicast source using a reduced PHY preamble and payload in a frame transmission to the coordinator based on the corresponding location information.

27. The system of claim 1 wherein the communication module comprises another management entity configured for directionally transmitting a data unit from a transmitting station over a channel in different directions to emulate omni-directional transmission.

28. The system of claim 27 wherein:

the receiving station is configured such that, if the difference between new location information and the previous measured location information is larger than a pre-defined threshold, then the receiving station transmits a location updating control frame to the coordinator station; and

the coordinator is further configured to updating the location information for the receiving station maintained by the coordinator.

29. The system of claim 28 wherein the coordinator is further configured for announcing the new location information for the receiving station in a next beacon transmission from the coordinator.

17. A system for device discovery in a wireless network, comprising:

a communication module configured for directionally transmitting a data unit from a transmitting station over a channel in different directions to emulate omni-directional transmission;

a management entity configured for receiving the data unit transmissions from different directions at a receiving station, determining the quality of the transmissions received from the different directions, and detecting location information for the transmitting station relative to the receiving station based on the highest quality transmission among the transmissions received from the different directions.

18. The system of claim 17 wherein the location information comprises a location vector including N elements corresponding to directional transmissions of a data unit in N different directions, wherein each vector element describes the signal quality of the transmission along a corresponding one of the N directions.

19. The system of claim 17 wherein the management entity is further configured for detecting location information by determining the direction of the transmitting station relative to the receiving station, as location information.

20. The system of claim 17 wherein said channel comprises a low-rate channel implementing orthogonal frequency division multiplexing (OFDM), providing both omni-directional and beam-steered modes.

21. The system of claim 20 wherein the communication module is further configured for directionally transmitting a data unit in different directions by beam-steering transmission of the data unit in said different directions.

22. The system of claim 20 wherein transmission data rates for the channel range from about 2.5 Mb/s to about 10 Mb/s for the omni-directional mode, and about 20 Mb/s to about 40 Mb/s for the beam-steered mode.

23. The system of claim 20 wherein the channel is in the about 57.2 GHz to about 65.8 GHz frequency band.

24. The system of claim 17 wherein the data unit comprises a frame.

25. The system of claim 17 wherein the receiving station maintains location information for the location information for each associated station.

26. The system of claim 18 further comprising a coordinator configured for periodically transmitting a beacon in omni-directional emulation mode, wherein N copies of the beacon are directionally transmitted in N different directions;

wherein the management entity is further configured for measuring and comparing the signal quality for copies of the beacon received from the coordinator in different directions, to determine a new location vector for the coordinator station, and determining a distance between the new location vector and an existing location vector.

30. The system of claim 18 further comprising:

a coordinator configured for maintaining location information for associated stations in the network relative to the coordinator;

a first associated station configured for sending a location query request control frame to the coordinator for location information of one or more other associated stations;

wherein the coordinator is further configured for providing location information of said one or more other associated stations to the first associated station; and

the first associated station is further configured for determining location information of a second device relative to the first associated device using;

the location information of the first associated device relative to the coordinator, and the location information of the second associated device relative to the coordinator.

31. The system of claim 18 further comprising:

a coordinator station configured for maintaining location information for associated stations in the network relative to the coordinator;

the coordinator further configured for periodically transmitting said location information in a beacon; and

an associated receiving station configured for using a reduced PHY preamble and reduced payload in a frame transmission to the coordinator based on the corresponding location information.

32. The system of claim 31 wherein:

the coordinator is further configured for maintaining location information for associated stations in the network relative to the coordinator;

the system further comprising a multicast source station in a multicast group configured for obtaining location information of stations in the multicast group by performing location query exchanges with the coordinator station, determining the location information of other stations in relation to the multicast source, and using a reduced PHY preamble and payload in a frame transmission to the coordinator based on the corresponding location information.

33. A method of wireless data communication, comprising the steps of:

receiving a request for wireless communication between two wireless stations over a wireless channel;

determining if the channel has sufficient bandwidth to satisfy the communication request;

if the channel has sufficient bandwidth to satisfy the communication request, establishing a direct communication link between the two stations over the channel, including the steps of;

during a direct link set-up stage, the two stations conducting a probing message exchange using omni-direction transmission; and

upon successful probing, obtaining communication link status information and setting proper communication configurations for the two stations based on the communication link status information.

34. A method of claim 33 wherein:

receiving a bandwidth request for wireless communication further includes receiving a bandwidth reservation request from a source station, within an unreserved channel time block (CTB); and

establishing a direct communication link further includes the steps of;

reserving CTBs for the requested bandwidth;

during a reserved CTB for direct link transmission (DLT), the source station probing a destination station by sending a DLT probe as a MAC command in omni-directional emulation mode in a low-rate channel, and waiting for a DLT probe response from the source station;

the destination station measuring and comparing the signal quality and other parameters of repetition copies of the DLT probe received in different directions from the source station, and determining the direction of the source station relative to the destination station; and

the destination station sending back a DLT probe response including channel coefficients information, to the source station.

35. The method of claim 34 wherein establishing a direct communication link further includes the steps of:

upon receiving a DLT probe response from the destination station, repeating a DLT probe request/response exchange between the source and destination stations to a threshold.

36. The method of claim 34 wherein establishing a direct communication link further includes the step of:

upon receiving a DLT probe response from the destination station, if probing of the destination station by the source station in omni-directional mode at the low-rate channel is successful, then the source station reporting a successful DLT set-up;

otherwise, the source station requesting release of the reserved CTBs due to DLT set-up failure.

37. The method of claim 36 wherein establishing a direct communication link further includes the steps of:

upon a successful DLT set-up;

performing link assessment/recommendation or beam-searching/steering in directional mode at a high-rate channel or the low-rate channel, to obtain accurate link status information in directional mode;

setting proper transmission/reception configurations for the two stations; and

communicating information in the reserved CTBs between the source and destination stations.

38. The method of claim 37 wherein communicating information in the reserved CTBs between the source and destination stations further includes the step of:

communicating audio/video/data streams in the reserved CTBs between the source and destination stations.

39. A system for wireless data communication, comprising the steps of:

a coordinator configured for receiving a request for wireless communication between two stations over a wireless channel, and determining if the channel has sufficient bandwidth to satisfy the communication request;

wherein the stations are configured such that, if the channel has sufficient bandwidth to satisfy the communication request, the station establish a direct communication link therebetween, wherein during a direct link set-up stage, the two stations conduct a probing message exchange using omni-direction transmission, and upon successful probing proper communication configurations for the two stations are set based on the communication link status information.

40. A system of claim 39 wherein:

the coordinator is configured for receiving a bandwidth reservation request from a source station, within an unreserved channel time block (CTB), such if the channel has sufficient bandwidth to satisfy the communication request, the coordinator reserves CTBs for the requested bandwidth;

the stations include a source station and a destination station, configured such that, during a reserved CTB for direct link transmission (DLT), the source station probes a destination station by sending a DLT probe as a MAC command in omni-directional emulation mode in a low-rate channel, and waits for a DLT probe response from the source station;

the destination station measures and compares the signal quality and other parameters of repetition copies of the DLT probe received in different directions from the source station, and determines the direction of the source station relative to the destination station; and

the destination station sends back a DLT probe response including channel coefficients information, to the source station.

41. The system of claim 40 wherein the stations are configured such that, upon receiving a DLT probe response from the destination station, if probing of the destination station by the source station in omni-directional mode at the low-rate channel is successful, then the source station reports a successful DLT set-up;

otherwise, the source station requests release of the reserved CTBs due to DLT set-up failure.

42. The system of claim 41 wherein the stations are configured such that, upon successful DLT set-up:

the stations perform link assessment/recommendation or beam-searching/steering in directional mode at a high rate channel or the low rate channel, to obtain accurate link status information in directional mode;

set proper transmission/reception configurations for the two stations; and

communicate information in the reserved CTBs between the source and destination stations.

43. The system of claim 42 wherein communicating information in the reserved CTBs between the source and destination stations comprises communicating audio/video/data streams in the reserved CTBs between the source and destination stations.