Method, system and components for facilitating wireless communication in a sectored service area

• US 20060105771A1
• Filed: 12/28/2004
• Published: 05/18/2006
• Est. Priority Date: 10/28/2004
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Chandra, Arty, Iacono, Ana Lucia, Zhao, Zheng
• Granted Patent: US 7,206,610 B2
• Time in Patent Office: Days
• US Class Current: 455/446
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

Network Allocation Vector (NAV) and “beam access control” (BAC) techniques are provided to address data collision problems in WLANs wherein APs provide wireless network access in a service area defined by multiple sectors via use of a switchable antenna system or the like. Preferably, every time the AP visits a sector and before the AP moves on to the next sector, the AP can set the NAV equal to the time it will take until its next visit. Alternatively, or in addition, a BAC bit is transmitted by an AP to control access to the AP by WTRUs disposed in a service sector in which the BAC is transmitted.

Claims

1. A method for an access point (AP) in a wireless local area network (WLAN) to provide communication services in a geographic area of service to wireless transmit/receive units (WTRUs), the method comprising:

selectively generating directional beams for providing communication service in sectors of the geographic service area such that each beam provides service to a predefined sector whereby collectively the directional beams provide service to the entire geographic service area;

controlling the generation of the directional beams to switch from beam to beam such that service is provided only during selected service periods in each sector; and

transmitting a signal to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam.

2. The method according to claim 1 wherein the transmitting a signal to WTRUs located in a sector includes transmitting a Network Allocation Vector (NAV) signal reflecting a time until service will resume in the sector.

3. The method according to claim 1 wherein the transmitting a signal to WTRUs located in a sector includes transmitting a beam access control (BAC) signal to WTRUs located in a sector indicating the cessation of a service period for that sector.

4. The method according to claim 3 wherein the transmitting a signal to WTRUs located in a sector includes transmitting a Network Allocation Vector (NAV) signal reflecting a time until service will resume in the sector.

5. The method according to claim 3 wherein the transmitting a signal to WTRUs located in a sector does not include a BAC signal.

6. The method according to claim 3 wherein the transmitting a signal to WTRUs located in a sector does not include a NAV signal.

7. The method according to claim 3 wherein:

the AP is operated in an IEEE 802.11 compliant system using predetermined frame formats; and

the transmitting a signal to WTRUs located in a sector indicating the cessation of a service period includes transmitting a BAC bit having a predetermined value in a frame to indicate cessation of a service period to the WTRUs in the sector.

8. The method according to claim 7 wherein the “

beam access control”

bit having a second value different than said predetermined value is transmitted in a directional beam during commencement of a service period for the sector associated with the directional beam to indicate commencement of a service period to WTRUs in the sector.

9. The method according to claim 8 wherein the “

beam access control”

bit is transmitted in a frame reserved for signaling of commencement and cessation of service periods, a beacon frame, a data frame, or another type of communication frame.

10. The method according to claim 1 wherein the controlling the generation of the directional beams includes:

defining service periods based on a scheduling algorithm for queuing and scheduling data packet transmissions by the AP; and

providing a service period for every sector in which to transmit a beacon signal at least once during a predefined beacon period (BP).

11. The method according to claim 10 wherein the defining service periods based on a scheduling algorithm includes adjusting the level of service to WTRUs in each sector by directing beams to lightly loaded sectors for shorter time periods than beams to heavily loaded sectors.

12. The method according to claim 1 where the AP is configured to operate in an IEEE 802.11 compliant system using predetermined frame formats wherein the provided communication services in each sector are based upon a relatively unique sector identifier which is transmitted in communication frames.

13. The method according to claim 12 wherein each WTRU is assigned to one sector based on a sector identifier during initial association with the AP.

14. A method for an access point (AP) in a wireless local area network (WLAN) to provide communication services in a geographic area of service to wireless transmit/receive units (WTRUs), the method comprising:

selectively generating directional beams for providing communication service in sectors of the geographic area of service such that each beam provides service to a predefined sector whereby collectively the directional beams provide service to the entire geographic service area; and

controlling the generation of the directional beams to switch from beam to beam such that service is provided only during selected service periods (SPs) in each sector during a predefined beacon period (BP) and such that a beacon service period (SP_beacon) is provided for every sector in which to transmit a beacon signal at least once during each BP; and

transmitting within each SP_beacon a beam access control (BAC) signal to control transmissions by WTRUs receiving the BAC signal during the BP.

15. The method according to claim 14 where all of the SP_beacons are provided consecutively at the beginning of each BP thereby defining a post beacon service period SP_postbeacon for the time remaining in the BP after the SP_beacons for that BP are completed, further comprising selecting a sector to be serviced at the start of the SP_postbeacon for a BP and transmitting a BAC signal to activate WTRU transmission capabilities in the selected sector'"'"'s SP_beacon for that BP and a BAC signal to de-activate WTRU transmission capabilities in each SP_beacon of the other sectors for that BP.

16. The method according to claim 15 where the SP_postbeacon for a BP is divided into sub service periods that collectively serve at least two different sectors.

17. The method according to claim 14 where a fixed duration SP is utilized.

18. An access point (AP) in a wireless local area network (WLAN) configured to provide communication services in a geographic area of service to wireless transmit/receive units (WTRUs), the AP comprising:

a transceiver configured to selectively generate directional beams for providing communication services in sectors of the geographic area of service such that each beam provides service to a predefined sector whereby collectively the directional beams provide service to the entire geographic service area; and

a control unit operatively associated with the transceiver and configured to control the generation of the directional beams by the transceiver to switch from beam to beam such that

service is provided only during selected periods in each sector; and

signals are transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam.

19. The AP according to claim 18 wherein the control unit is operatively associated with the transceiver such that the signals transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam, include Network Allocation Vector (NAV) signals reflecting a time until service will resume in the sector.

20. The AP according to claim 18 wherein the control unit is operatively associated with the transceiver such that the signals transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam, include beam access control (BAC) signals indicating the cessation of a service period for that sector.

21. The AP according to claim 20 wherein the control unit is operatively associated with the transceiver such that the signals transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam, include Network Allocation Vector (NAV) signals reflecting a time until service will resume in the sector.

22. The AP according to claim 20 configured to operate in an IEEE 802.11 compliant WLAN using predetermined frame formats wherein the transceiver is configured to transmit a BAC signal to WTRUs located in a sector indicating the cessation of a service period by transmitting a BAC bit having a predetermined value in a frame to indicate cessation of a service period to the WTRUs in the sector.

23. An access point (AP) in a wireless local area network (WLAN) configured to provide communication services in a geographic area of service to wireless transmit/receive units (WTRUs), the AP comprising:

a transceiver configured to selectively generate directional beams for providing communication service in sectors of the geographic area of service such that each beam provides service to a predefined sector whereby collectively the directional beams provide service to the entire geographic service area; and

a control unit operatively associated with the transceiver and configured to control the generation of the directional beams by the transceiver to switch from beam to beam such that

service is provided only during selected service periods (SPs) in each sector during a predefined beacon period (BP);

a beacon service period (SP_beacon) is provided for every sector in which to transmit a beacon signal at least once during each BP; and

a beam access control (BAC) signal is transmitted within each SP_beacon to control transmissions by WTRUs receiving the BAC signal during the BP.

24. The AP according to claim 23 configured to operate in an IEEE 802.11 compliant WLAN using predetermined frame formats wherein the transceiver is configured to transmit a BAC signal to WTRUs located in a sector by transmitting a BAC bit having a predetermined value in a frame to the WTRUs in the sector.

25. A wireless transmit/receive unit (WTRU) configured for use in a wireless local area network (WLAN) in which an access point (AP) generates directional beams to provide communication service in sectors of a geographic area of service such that service is provided only during selected periods in each sector, the WTRU comprising:

a transceiver configured to receive a beam access control (BAC) signal transmitted by an AP providing service in a sector in which the WTRU is then located that indicates the cessation of a service period for that sector and to suspend transmission of signals to the AP until receiving a further BAC signal from the AP.

26. The WTRU according to claim 25 configured to operate in an IEEE 802.11 compliant WLAN using predetermined frame formats wherein the transceiver is configured to receive a BAC signal from an AP having multiple service sectors indicating the cessation of a service period within a sector in which the WTRU is disposed by receiving a BAC bit having a predetermined value in a frame to indicate cessation of the service period.

27. A wireless local area network (WLAN) comprising:

an access point (AP) configured to provide communication services in a geographic area of service to wireless transmit/receive units (WTRUs) including;

a transceiver configured to selectively generate directional beams for providing communication service in sectors of the geographic area of service such that each beam provides service to a predefined sector whereby collectively the directional beams provide service to the entire geographic service area; and

a control unit operatively associated with the transceiver and configured to control the generation of the directional beams by the transceiver to switch from beam to beam such that

service is provided only during selected periods in each sector; and

signals are transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam; and

at least one wireless transmit/receive unit (WTRU) having a transceiver configured to receive signals transmitted by an AP providing service in a sector in which the WTRU is then located to suspend WTRU transmissions.

28. The WLAN according to claim 27 wherein the AP control unit is operatively associated with the AP transceiver such that the AP signals transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam, include Network Allocation Vector (NAV) signals reflecting a time until service will resume in the sector and wherein the WTRU transceiver is configured to receive NAV signals transmitted by an AP providing service in a sector in which the WTRU is then located to suspend transmission of signals to the AP until the expiration of the time reflected in the NAV signal.

29. The WLAN according to claim 27 wherein the AP control unit is operatively associated with the AP transceiver such that the AP signals transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam, include beam access control (BAC) signals indicating the cessation of a service period for that sector and wherein the WTRU transceiver is configured to receive BAC signals transmitted by an AP providing service in a sector in which the WTRU is then located that indicates the cessation of a service period for that sector and to suspend transmission of signals to the AP until receiving a further BAC signal from the AP.

30. The WLAN according to claim 29 wherein the AP control unit is operatively associated with the AP transceiver such that the AP signals transmitted to WTRUs located in a sector to suspend WTRU transmissions by such WTRUs, before switching to another beam to provide service in the sector associated with the other beam, include Network Allocation Vector (NAV) signals reflecting a time until service will resume in the sector and wherein the WTRU transceiver is configured to receive NAV signals transmitted by an AP providing service in a sector in which the WTRU is then located to suspend transmission of signals to the AP until the expiration of the time reflected in the NAV signal.