BASE STATION AND METHOD FOR SELECTING BEST TRANSMIT ANTENNA(s) FOR SIGNALING CONTROL CHANNEL INFORMATION

Abstract

A base station is described herein which implements a method that uses different aspects of reported channel quality information (CQI) measurements to help select the “best” transmit antenna(s) on which to transmit control channel information to mobile terminal(s). The base station can also transmit a format indicator to communicate the assigned control channel transmit antenna(s) and the assigned data transmit antenna(s) to the mobile terminal(s).

1 . A method for selecting one or more transmit antennas from which to transmit control channel information to one or more receivers, said method comprising the steps of: 
 receiving channel quality information measurements from the one or more receivers; and    analyzing the received channel quality information measurements to select which transmit antenna(s) to use for transmitting the control channel information to the one or more receivers.    
   
   
       2 . The method of  claim 1 , further comprising the step of transmitting a format indicator to the one or more receivers where the format indicator identifies the transmit antenna assignments for both data information and the control channel information.  
   
   
       3 . The method of  claim 1 , wherein when said received channel quality information measurements have a specific antenna detection ordering then said analyzing step results in selecting the transmit antenna(s) which are going to be detected first by the one or more receivers.  
   
   
       4 . The method of  claim 1 , wherein when said received channel quality information measurements have a value for each sub-band within a signal bandwidth for each transmit antenna then said analyzing step includes a step of restricting the selection of possible transmit antenna(s) that could be used to transmit the control data information to be from a group of transmit antenna(s) which had been selected to transmit data to the one or more receivers.  
   
   
       5 . The method of  claim 4 , wherein said restricting step further includes a step of using a sum data rate over each sub-band within the signal bandwidth for each transmit antenna that is used for data transmission when determining the transmit antenna(s) which are to be used to transmit the control data information to the one or more receivers.  
   
   
       6 . The method of  claim 4 , wherein said restricting step further includes a step of restricting the sub-band(s) within the signal bandwidth for each transmit antenna that could be used to transmit the control data information to the one or more receivers.  
   
   
       7 . The method of  claim 1 , wherein when said received channel quality information measurements have a specific antenna detection ordering and a value corresponding to each sub-band within a signal bandwidth for each transmit antenna then said analyzing step includes a step of computing a sum data rate for each potential transmit antenna and a step of assigning the control data information to the transmit antenna(s) which are going to be detected first by the one or more receivers.  
   
   
       8 . The method of  claim 1 , wherein when the control channel information is transmitted to multiple receivers then said analyzing step includes a step of selecting the transmit antenna(s) which satisfy the most disadvantaged receiver of the multiple receivers.  
   
   
       9 . The method of  claim 1 , further comprising a step of transmitting a format indicator to the one or more receivers where the format indicator identifies a first transmit antenna assignment for the control channel information and a first detected transmit antenna of the data channel and a second transmit antenna assignment for the remaining detected antennas of the data channel.  
   
   
       10 . The method of  claim 9 , further comprising the step of transmitting the portion of the format indicator that identifies a first transmit antenna assignment for the control channel information and the first detected transmit antenna to the one or more receivers on a first transmission and transmitting the portion of the format indicator that identifies the second transmit antenna assignment for the remaining detected antennas of the data channel on a second transmission to the one or more receivers.  
   
   
       11 . A base station comprising: 
 a user scheduling unit that receives channel quality information measurements and outputs user scheduling information and control channel information;    a control channel antenna mapping unit that receives the channel quality information measurements and the user scheduling information and processes the channel quality information measurements and the user scheduling information to select which transmit antenna(s) should be used to transmit the control channel information; and    an antenna switch that receives a transmit antenna selection from said control channel antenna mapping unit and the control channel information from said user scheduling unit and then uses the selected transmit antenna(s) to transmit the control channel information.    
   
   
       12 . The base station of  claim 11 , wherein said control channel antenna mapping unit specifies a format indicator to indicate transmit antenna assignments for both data information and the control channel information.  
   
   
       13 . The base station of  claim 11 , wherein when said received channel quality information measurements have a specific ordering then said control channel antenna mapping unit selects the transmit antenna which is first detected by a receiver.  
   
   
       14 . The base station of  claim 11  wherein when said received channel quality information measurements have no specific ordering then said control channel antenna mapping unit selects the transmit antenna(s) which have a highest individual data rate(s) from a group of transmit antenna(s) that had been selected to transmit data to a receiver.  
   
   
       15 . The base station of  claim 14 , wherein when said received channel quality information measurements have no specific ordering then said control channel antenna mapping unit selects the transmit antenna(s) which have a highest sum data rate(s) from a group of transmit antenna(s) that had been selected to transmit data to a receiver.  
   
   
       16 . The base station of  claim 11 , wherein when the control channel information is transmitted to multiple receivers then said control channel antenna mapping unit selects the transmit antenna(s) which satisfy the most disadvantaged receiver of the multiple receivers.  
   
   
       17 . The base station of  claim 11 , wherein said user scheduling unit, said control channel antenna mapping unit and said antenna switch are part of an orthogonal frequency division multiplexing system.  
   
   
       18 . A receiver comprising: 
 a receiving unit that receives a format indicator from a base station; and    a processor that processes the format indicator to determine which transmit antenna(s) in the base station are going to transmit control data channel information and which transmit antenna(s) in the base station are going to transmit data information.    
   
   
       19 . The receiver of  claim 18 , further comprising a transmitting unit that transmits channel quality information measurements associated with the transmit antennas in the base station where the channel quality information measurements have a specific ordering.  
   
   
       20 . The receiver of  claim 18 , further comprising a transmitting unit that transmits channel quality information measurements associated with the transmit antennas in the base station where the channel quality information measurements have a value corresponding to each sub-band within a signal bandwidth for each transmit antenna in the base station.