Mobile radio network

Abstract

A mobile radio network comprises a plurality of communication points, each of which are capable of communicating with any other communication point. Each communication point has a proximity sensor, a transmitter/receiver ( 14 ), which is able to send signals to and receive signals from the other communication points. Means for controlling the transmitter/receiver and means for storing data to identify the communication points is also described.

1 . A mobile communication point for use in a mobile radio network comprising a plurality of communication points, each capable of communicating with other communication points, the mobile communication point comprising
 a transmitter/receiver for sending signals to and receiving signals from the other communication points;   a control element for switching between a high power mode in which said mobile communication point is able to transmit or receive signals and a low power mode in which said mobile communication point is in a sleep state and is unable to transmit or receive signals; and   a processor coupled to the control element for:
 enabling the communication to switch from the low power mode to the high power mode on a periodic basis 
 broadcasting a unique identity packet on switching into the high power mode; and 
 waiting a predetermined time after broadcasting to detect whether any other communication point to attempting to transmit back and, if so, remaining in the high power mode; otherwise 
 returning to the low power mode for a predetermined period of time. 
   
   
   
       2 . A mobile communication point according to  claim 1  in which said mobile communication point remains able to transmit or receive signals for an extended period of time upon receiving a response during the predetermined period. 
   
   
       3 . A mobile communication point according to  claim 1  in which the communication point includes means responsive to an external input to cause the control element to switch the communication point from low power mode to high power mode. 
   
   
       4 . A mobile communication point according to  claim 3  in which the means responsive to an external input comprises a low power RF detection circuit responsive to a radio transmission. 
   
   
       5 . A mobile communication point according to  claim 3  in which the means responsive to an external input comprises an ultrasonic detector. 
   
   
       6 . A mobile communication point according to  claim 3  in which the means responsive to an external input comprises an infrared detector. 
   
   
       7 . A mobile communication point according to  claim 3  in which the means responsive to an external input comprises a manual input. 
   
   
       8 . A mobile communication point according to  claim 1  wherein the processor further comprises
 a data storage means storing the unique identity packet associated with said mobile communication point and storing data identifying other recently-contacted communication points, wherein the mobile communication point determines whether data about a second mobile communication point is stored in its data storage means upon receipt of a transmission from the second mobile communication point.   
   
   
       9 . A communication point according to  claim 8  in which the mobile communication point is responsive to a transmission from a second mobile communication point to send interrogation signals to said second mobile communication point. 
   
   
       10 . A mobile radio system comprising a plurality of mobile communication points capable of communicating with each other, each communication point comprising
 a transmitter/receiver for sending signals to and receiving signals from the other communication points;   a control element for switching between a high power mode in which said mobile communication point is able to transmit or receive signals and a low power mode in which said mobile communication point is in a sleep state and is unable to transmit or receive signals; and   a processor coupled to the control element for:
 enabling the communication to switch from the low power mode to the high power mode on a periodic basis 
 broadcasting a unique identity packet on switching into the high power mode; and 
 waiting a predetermined time after broadcasting to detect whether any other communication point to attempting to transmit back and, if so, remaining in the high power mode; otherwise 
 returning to the low power mode for a predetermined period of time. 
   
   
   
       11 . A mobile radio system as defined in  claim 10  wherein each mobile communication point further comprises
 a data storage means storing the unique identity packet associated with said mobile communication point and storing data identifying other recently-contacted communication points, wherein the mobile communication point determines whether data about a second mobile communication point is stored in its data storage means upon receipt of a transmission from the second mobile communication point.