Radio communications device with adaptive combination

Abstract

To reduce costs in multiple-input multiple-output (MIMO) and other wireless communication systems an arrangement is described whereby adaptive combination is used at user equipment in order to produce two or more directional antenna beams. Improvements in carrier to interference levels result.

1 . A radio communications device comprising 
 (i) a plurality of antenna elements; and    (ii) a combiner arranged to adaptively combine said antenna elements such that two or more directional antenna beams are provided which are diverse.    
     
     
         2 . A radio communications device as claimed in  claim 1  which is a multiple-input multiple-output (MIMO) communications device and wherein the combiner is arranged such that the two or more directional antenna beams are suitable for MIMO communications.  
     
     
         3 . A radio communications device as claimed in  claim 1  which is selected from a user terminal and a basestation.  
     
     
         4 . A radio communications device as claimed in  claim 1  wherein said antenna beams are diverse as a result of any of polarisation diversity, angle diversity and space diversity.  
     
     
         5 . A radio communications device as claimed in  claim 1  wherein said combiner comprises at least one beamformer.  
     
     
         6 . A radio communications device as claimed in  claim 1  wherein at least some of said antenna elements are provided as a phased array.  
     
     
         7 . A radio communications device as claimed in  claim 1  wherein a pair of antenna beams are provided with substantially orthogonal polarisations and at substantially similar directions.  
     
     
         8 . A radio communications device as claimed in  claim 7  wherein a second pair of antenna beams is provided also with substantially orthogonal polarisations to one another and at substantially similar directions but being at a different direction from the first pair of antenna beams.  
     
     
         9 . A radio communications device as claimed in  claim 1  wherein said combiner is arranged to electronically steer the directional antenna beams.  
     
     
         10 . A communications network comprising a plurality of radio communications devices as claimed in  claim 1 .  
     
     
         11 . A method of operating a radio communications device comprising the steps of: 
 (i) receiving radio signals at a plurality of antenna elements by;    (ii) using a combiner to adaptively combine the antenna elements such that they are operable in at least one direction to receive two or more diverse channels.    
     
     
         12 . A method as claimed in  claim 11  wherein said radio communications device is a multiple-input multiple-output communications device and wherein said received signals are space-time coded and said diverse channels are multiple-input multiple-output channels.  
     
     
         13 . A method of operating a radio communications device comprising the steps of: 
 (i) transmitting radio signals from a plurality of antenna elements by;    (ii) using a combiner to adaptively combine the antenna elements such that they are operable in at least one direction to transmit two or more diverse channels.    
     
     
         14 . A method of operating a radio communications device as claimed in  claim 13  which is a multiple-input multiple-output communications device and wherein said radio signals are space-time coded and said diverse channels are multiple-input multiple-output channels.