Synchronization of terminals in a radio link system

Abstract

The objective of the invention is to increase the potential hop density of single frequency TDD radio links by allowing a set of closely located terminals to use a single channel. This is possible when transmission and reception periods of the terminals are synchronized so that the transmit period of any of the terminals in a terminal group does not overlap with the receive period of any of the terminals in the group. Synchronization is achieved by selecting at least one terminal in a hub site as a super master terminal. This terminal gives timing through a common bus to the rest of the terminals in the group These terminals use the received timing for adjusting their own timing i.e. for adjusting the starting moment and ending moment of the transmission and reception periods in such a manner that none of terminals is sending a burst while another terminal is receiving.

1 . A terminal for a radio link system operating in time division duplex mode, comprising 
 means for receiving synchronization information from a second terminal via a synchronization bus,    means for transmitting synchronization information to a plurality of second terminals via a synchronization bus, and    means for adjusting transmission periods according to received synchronization information.    
   
   
       2 . A terminal according to  claim 1 , comprising means for transmitting synchronization information over a radio link to a second terminal.  
   
   
       3 . A terminal according to  claim 1 , comprising 
 means for receiving frequency information from a second terminal via a synchronization bus, and    means for adjusting a transmission frequency of the terminal according to received frequency information.    
   
   
       4 . A terminal according to  claim 1 , comprising means for transmitting frequency information to a plurality of second terminals via a synchronization bus.  
   
   
       5 . A terminal for a radio link system operating in time division duplex mode, wherein the terminal is configured to 
 receive synchronization information from a second terminal via a synchronization bus, and    adjust transmission periods according to received synchronization information.    
   
   
       6 . A terminal according to  claim 5 , wherein the terminal is configured to transmit synchronization information over a radio link to a second terminal.  
   
   
       7 . A terminal according to  claim 5 , wherein the terminal is configured to 
 receive frequency information from a second terminal via a synchronization bus, and    adjust a transmission frequency of the terminal according to received frequency information.    
   
   
       8 . A terminal for a radio link system operating in time division duplex mode, wherein the terminal is configured to transmit synchronization information to a plurality of second terminals via a synchronization bus.  
   
   
       9 . A terminal according to  claim 8 , wherein the terminal is configured to transmit synchronization information over a radio link to a second terminal.  
   
   
       10 . A terminal according to  claim 8 , wherein the terminal is configured to transmit frequency information to a plurality of second terminals via a synchronization bus.