Reduced computation in joint detection

Abstract

A user equipment receives a plurality of transmitted data signals in a communication system. The transmitted data are received. A channel response is determined for each received data signal. A system response is determined based on in part the channel signals. The system response is expanded to be piecewise orthogonal. Data from the received data signals is retrieved based on in part the expanded system response.

1 . A circuit for receiving a plurality of transmitted data signals, the circuit comprising: 
 an antenna for receiving the transmitted data signals;    a channel estimation device for determining a channel response for each received data signal; and    a joint detection device having an input configured to receive the channel responses and the received data signals for determining a system response based on in part the channel signals, expanding the system response to be piecewise orthogonal, and retrieving data from the received data signals based on in part the expanded system response.    
   
   
       2 . The circuit of  claim 1  for use in a time division duplex using code division multiple access communication system.  
   
   
       3 . The circuit of  claim 2  wherein each of the transmitted data signals has an associate code and is transmitted in a shared frequency spectrum and the system response is determined by convolving associated chip codes with the channel response.  
   
   
       4 . The circuit of  claim 2  wherein the channel estimation device measures the channel response using a received training sequence associated with the data signals.  
   
   
       5 . The circuit of  claim 1  wherein the system response is a system response matrix, further comprising dividing the system response matrix into blocks of columns prior to the expanding.  
   
   
       6 . The circuit of  claim 5  wherein the expanding is by padding zeros in the column blocks such that each column block is orthogonal.