Patent ID: 7299072
Filing Date: 2007-11-20
Classification: H04W

Abstract:
1. An apparatus for a wireless base station for use in a wireless local area network (LAN) sharing one frequency channel, said apparatus being adapted to communicate with a plurality of wireless terminals in a plurality of sectors, said apparatus comprising: a communication control unit, and a plurality of transceivers associated with said sectors, respectively, said transceivers having respective directive antennas associated with said respective sectors, wherein, during a first period of time, said communication control unit causes all of said transceivers in all of said sectors to transmit and receive RF signals at said frequency channel to and from said plurality of wireless terminals, determines locations of said wireless terminals in the sectors, in accordance with identification codes of said wireless terminals and with identifications of said transceivers which receive said identification codes, and stores, in a location management table, information indicating which wireless terminals are located in each sector, during a second period of time subsequent to said first period of time, said communication control unit enables one or more of said plurality of transceivers that are associated with respective one or more of said plurality of sectors that are not adjacent to each other, to transmit and receive RF signals at said frequency channel to and from wireless terminals, and said communication control unit disables remaining one or more transceivers other than said enabled one or more transceivers, from transmission to wireless terminals, and during a third period of time subsequent to said second period of time, said communication control unit enables further one or more of said plurality of transceivers that are associated with respective further one or more of said plurality of sectors that are not adjacent to each other, to transmit and receive RF signals at said frequency channel to and from wireless terminals, said further one or more transceivers being disabled in said second period of time from transmitting, and said communication control unit disables further remaining one or more transceivers other than said enabled further one or more transceivers, from transmission to wireless terminals, wherein time periods associated with said second period of time and time periods associated with said third period of time are sequentially and alternately executed, a predetermined length of time before the change from a time period associated with said second period of time to a time period associated with said third period of time, said transceiver which is enabled to transmit and receive RF signals starts detection of an RF signal transmitted by a wireless terminal located in a corresponding sector, and broadcasts a packet indicative of disabling transmission between said transceiver and wireless terminals in said corresponding sector during said third period of time and indicative of a length of said third period of time to wireless terminals in said corresponding sector, during which said transceiver does not receive an RF signal, wherein said transceiver broadcasts said packet in response to said transceiver not detecting a transmitted RF signal, and wherein, in response to said transceiver detecting a transmitted RF signal, said transceiver broadcasts said packet after completion of transmission of the transmitted RF signal, a predetermined length of time before the change from a time period associated with said third period of time to a time period associated with said second period of time, said transceiver which is enabled to transmit and receive RF signals starts detection of an RF signal transmitted by a wireless terminal located in a corresponding sector, and broadcasts a packet indicative of disabling transmission between said transceiver and wireless terminals in said corresponding sector during said second period of time and indicative of a length of said second period of time to wireless terminals in said corresponding sector, during which said transceiver does not receive an RF signal, wherein said transceiver broadcasts said packet in response to said transceiver not detecting a transmitted RF signal, and wherein, in response to said transceiver detecting a transmitted RF signal, said transceiver broadcasts said packet after completion of transmission of the transmitted RF signal, and the communication control unit determines whether time periods associated with said second period of time and time periods associated with said third period of time have been sequentially and alternately executed a predetermined number of times and executes a time period associated with said first period of time based on said determination.