Multi-channel WLAN transceiver with antenna diversity

Abstract

An access point for use in a wireless local area network (WLAN) includes a plurality of antennas and two or more transmitters, which are adapted to transmit downlink signals on different, respective downlink frequency channels of the WLAN via at least one of the antennas. Two or more receivers are coupled to receive uplink signals via at least two of the antennas, and are adapted to receive the uplink signals simultaneously on different, respective uplink frequency channels of the WLAN.

1 . An access point for use in a wireless local area network (WLAN), the access point comprising: 
 a plurality of antennas;    two or more transmitters, which are adapted to transmit downlink signals on different, respective downlink frequency channels of the WLAN via at least one of the antennas; and    two or more receivers, each of which is coupled to receive uplink signals via at least two of the antennas, and which are adapted to receive the uplink signals simultaneously on different, respective uplink frequency channels of the WLAN.    
     
     
         2 . The access point according to  claim 1 , and comprising at least one radio frequency (RF) multiplexer, coupled between the at least two of the antennas and the two or more receivers, so as to convey to each of the receivers the uplink signals received via the antennas on the respective uplink frequency channels.  
     
     
         3 . The access point according to  claim 2 , wherein the two or more receivers comprise three receivers, which are tuned to operate on three respective uplink frequency channels, and wherein the at least one multiplexer comprises two triplexers, coupled respectively to two of the antennas, so as to split the uplink signals received via each of the antennas among the three receivers according to the three frequency channels.  
     
     
         4 . The access point according to  claim 1 , wherein the receivers are adapted to process the uplink signals from the at least two of the antennas simultaneously, so as to improve a fidelity of the received uplink signals based on a diversity of the antennas.  
     
     
         5 . The access point according to  claim 1 , wherein the transmitters and receivers are adapted to communicate with mobile stations in the WLAN substantially in accordance with an IEEE 802.11 specification, which defines the uplink and downlink frequency channels.  
     
     
         6 . The access point according to  claim 1 , wherein the access point is one of a plurality of access points in the WLAN, and comprises: 
 a communication interface, coupled to a medium for communicating with the other access points; and    processing and control circuitry, which is adapted to send and receive messages to and from the other access points via the communication interface, so as to make a determination of when each of the two or more transmitters should transmit the downlink signals, and which is coupled to control the two or more transmitters according to the determination.    
     
     
         7 . The access point according to  claim 6 , wherein the communication medium comprises a wired local area network (LAN).  
     
     
         8 . The access point according to  claim 6 , wherein the processing and control circuitry is adapted, when one of the receivers receives an uplink signal transmitted over the WLAN by a mobile station on one of the uplink frequency channels, to send and receive the messages in accordance with an arbitration protocol carried out together with others of the access points receiving the uplink signal, so as to select one of the access points to respond to the uplink signal, and to control the two or more transmitters so that one of the transmitters returns a response to the mobile station subject to the arbitration protocol.  
     
     
         9 . The access point according to  claim 8 , wherein the processing and control circuitry is adapted to control the two or more transmitters so that when the access point is selected, the response is returned to the mobile station by one of the transmitters on one of the downlink frequency channels that corresponds to the one of the uplink frequency channels on which the uplink signal was received.  
     
     
         10 . The access point according to  claim 6 , wherein the processing and control circuitry is adapted to control the two or more transmitters so as to cause at least two of the transmitters to transmit the downlink signals simultaneously on the respective downlink frequency channels.  
     
     
         11 . A system for mobile communication, comprising: 
 a communication medium; and    a plurality of access points interconnected by the medium and arranged to communicate with mobile stations in a wireless local area network (WLAN), each of at least some of the access points comprising: 
 a plurality of antennas;  
 two or more transmitters, which are adapted to transmit downlink signals to the mobile stations on different, respective downlink frequency channels of the WLAN via at least one of the antennas;  
 two or more receivers, each of which is coupled to receive uplink signals from the mobile stations via at least two of the antennas, and which are adapted to receive the uplink signals simultaneously on different, respective uplink frequency channels of the WLAN;  
 a communication interface, coupled to the communication medium; and  
 processing and control circuitry, which is adapted to send and receive messages to and from the other access points via the communication interface, so as to make a determination of when each of the two or more transmitters should transmit the downlink signals, and which is coupled to control the two or more transmitters according to the determination.  
   
     
     
         12 . The system according to  claim 11 , wherein the access points have respective service areas and are arranged so that at least some of the service areas substantially overlap.  
     
     
         13 . The system according to  claim 11 , wherein each of the at least some of the access points comprises at least one radio frequency (RF) multiplexer, coupled between the at least two of the antennas and the two or more receivers, so as to convey to each of the receivers the uplink signals received via the antennas on the respective uplink frequency channels.  
     
     
         14 . The system according to  claim 11 , wherein the receivers in each of the at least some of the access points are adapted to process the uplink signals from the at least two of the antennas simultaneously, so as to improve a fidelity of the received uplink signals based on a diversity of the antennas.  
     
     
         15 . The system according to  claim 11 , wherein the transmitters and receivers are adapted to communicate with mobile stations in the WLAN substantially in accordance with an IEEE 802.11 specification, which defines the uplink and downlink frequency channels.  
     
     
         16 . The system according to  claim 11 , wherein the communication medium comprises a wired local area network (LAN).  
     
     
         17 . The system according to  claim 11 , wherein the processing and control circuitry is adapted, when one of the receivers receives an uplink signal transmitted over the WLAN by a mobile station on one of the uplink frequency channels, to send and receive the messages in accordance with an arbitration protocol carried out together with others of the access points receiving the uplink signal, so as to select one of the access points to respond to the uplink signal, and to control the two or more transmitters so that one of the transmitters returns a response to the mobile station subject to the arbitration protocol.  
     
     
         18 . The system according to  claim 11 , wherein the processing and control circuitry is adapted to control the two or more transmitters so as to cause at least two of the transmitters in one of the access points to transmit the downlink signals simultaneously on the respective downlink frequency channels.  
     
     
         19 . A method for mobile communication, comprising: 
 arranging a plurality of access points in a wireless local area network (WLAN), at least some of the access points comprising two or more transmitters and two or more receivers, which are adapted to communicate with mobile stations over the WLAN on different, respective downlink and uplink frequency channels;    receiving at one of the receivers in each of one or more of the access points an uplink signal transmitted over the WLAN by one of the mobile stations on one of the uplink frequency channels;    arbitrating among the access points receiving the uplink signal so as to select one of the access points to respond to the uplink signal; and    actuating one of the transmitters in the selected one of the access points to transmit a response to the one of the mobile stations on one of the downlink frequency channels corresponding to the one of the uplink frequency channels on which the uplink signal was received.    
     
     
         20 . The method according to  claim 19 , wherein the access points have respective service areas, and wherein arranging the plurality of access points comprises arranging the access points so that at least some of the service areas substantially overlap.  
     
     
         21 . The method according to  claim 19 , wherein receiving the uplink signal comprises receiving the signal via at least two antennas at each of the one or more of the access points, wherein the antennas are coupled to the two or more receivers so that uplink signals are split among the receivers according to the respective uplink frequency channels.  
     
     
         22 . The method according to  claim 21 , wherein receiving the uplink signal comprises processing the uplink signal from the at least two antennas simultaneously, so as to improve a fidelity of the received uplink signals based on a diversity of the antennas.  
     
     
         23 . The method according to  claim 19 , wherein arranging the plurality of access points comprises configuring the transmitters and receivers so as to communicate with the mobile stations in the WLAN substantially in accordance with an IEEE 802.11 specification, which defines the uplink and downlink frequency channels.  
     
     
         24 . The method according to  claim 19 , wherein arbitrating among the access points comprises sending and receiving messages among access points via a communication medium, so as to select the one of the access points to respond to the uplink signal.