Synchronised radio transceivers

Abstract

Disclosed are a method of and apparatus for controlling a first radio transceiver 18 and a second radio transceiver 20 which are connected to a common oscillator 16, wherein each transceiver 18, 20 is capable of communicating with one or more remote radio transceivers 12, 14. The method comprises: the first transceiver 18 sending a synchronisation signal to the second transceiver 20; and the second transceiver 20 using the synchronisation signal to ensure that neither transceiver 18, 29 transmits data while the other transceiver is in a receiving state.

1 . A method of controlling a first radio transceiver and a second radio transceiver which are connected to a common oscillator, wherein each transceiver is capable of communicating with one or more remote radio transceivers, the method comprising:
 the first transceiver sending a synchronisation signal to the second transceiver; and   the second transceiver using the synchronisation signal to ensure that neither transceiver transmits data while the other transceiver is in a receiving state.   
     
     
         2 . A method as claimed in  claim 1  wherein the common oscillator is a crystal oscillator. 
     
     
         3 . A method as claimed in  claim 1  comprising each transceiver switching periodically from a transmitting state, in which the transceiver is able to transmit data, to a receiving state, in which the transceiver is able to receive data. 
     
     
         4 . A method as claimed in  claim 3  wherein a time period between each successive switching to the receiving state is substantially the same for both transceivers. 
     
     
         5 . A method as claimed in  claim 3  comprising each transceiver regulating its switching into the receiving state using a signal from the common oscillator. 
     
     
         6 . A method as claimed in  claim 3  comprising the second receiver using the synchronisation signal to control a phase offset between the periodic switching of the first transceiver and the periodic switching of the second transceiver in order that neither transceiver transmits data while the other transceiver is in a receiving state. 
     
     
         7 . A method as claimed in  claim 1  comprising the first transceiver sending a synchronisation signal at a predetermined position within its switching cycle. 
     
     
         8 . A method as claimed in  claim 7  wherein the synchronisation signal comprises a square wave in a predetermined phase relationship with the periodic switching of the first transceiver. 
     
     
         9 . A method as claimed in  claim 1  comprising the second transceiver generating a local signal identical to the synchronisation signal. 
     
     
         10 . A method as claimed in  claim 1  comprising the second transceiver delaying or advancing the timing of its switching period so as to align in time the local signal with the received synchronisation signal. 
     
     
         11 . A method as claimed in  claim 1  comprising sending the synchronisation signal over an optical, electronic or mechanical connection between the first and second radio transceivers. 
     
     
         12 . A method as claimed in  claim 1  wherein the first and second radio transceivers are, or comprise, respective identical integrated circuits. 
     
     
         13 . A method as claimed in  claim 12  comprising each integrated circuit receiving a designation instruction which determines whether the integrated circuit operates as the first transceiver or as the second transceiver. 
     
     
         14 . A method as claimed in  claim 1  comprising the transceivers toggling directly from the transmitting state to the receiving state and back again in one switching period. 
     
     
         15 . A method as claimed in  claim 1  wherein the durations of the transmitting states of the first and second transceivers are equal or substantially equal. 
     
     
         16 . A method as claimed in  claim 1  wherein the durations of the receiving states of the first and second transceivers are equal or substantially equal. 
     
     
         17 . A method as claimed in  claim 1  wherein the first and second transceivers both switch from the receiving state to the transmitting state at the same point within their respective switching periods. 
     
     
         18 . A method as claimed in  claim 1  wherein the transceivers are in a transmitting state for less time than they are in a receiving state. 
     
     
         19 . A method as claimed in  claim 1  wherein one or both transceivers carries out half-duplex radio communication with the remote apparatus. 
     
     
         20 . A method as claimed in  claim 1  wherein the remote apparatus comprises third and fourth radio transceivers in radio communication with the first and second transceivers respectively. 
     
     
         21 . A method as claimed in  claim 20  wherein the third and fourth radio transceivers synchronise their radio transmissions from synchronisation information sent by radio from the first and/or second radio transceivers. 
     
     
         22 . A method as claimed in  claim 1  wherein the transceivers transmit and/or receive audio or video data. 
     
     
         23 . A system comprising a first radio transceiver and a second radio transceiver which are connected to a common oscillator, wherein each transceiver is capable of communicating with one or more remote radio transceivers, wherein:
 the first transceiver is configured to send a synchronisation signal to the second transceiver; and   
       the second transceiver is configured to use the synchronisation signal to ensure that neither transceiver transmits data while the other transceiver is in a receiving state. 
     
     
         24 . A radio transceiver arranged for connection to an oscillator, and being capable of communicating with one or more remote radio transceivers, wherein the transceiver is configured:
 to receive a synchronisation signal from a second transceiver connected to the same oscillator, and to use the synchronisation signal to ensure that the transceiver does not transmit data while the second transceiver is in a receiving state and to ensure that the transceiver is not in a receiving state while the second transceiver transmits data.