Uplink interference cancellation

A method of operating a CDMA based wireless base station, the method comprising:

• receiving a channel request from a mobile terminal;
• sending an acknowledgement including an assigned code to the mobile terminal;
• determining the relative transmission timing of the mobile terminal;
• determining a cross-correlation parameter associated with the requesting mobile terminal assigned code and transmission timing and another mobile terminal communicating with the base station and having another code and transmission timing;
• receiving data from the requesting mobile terminal using said assigned code and transmission timing;
• and
• cancelling interference on said received data caused by data received from said other mobile terminal on said other code and other transmission timing, said interference cancellation using the cross-correlation parameter, wherein the interference cancelling comprises calculating an interference signal associated with the other mobile terminal and subtracting this from the received data signal in order to recover the data signal without said interference signal, wherein an accuracy parameter is calculated for the interfering signal, and wherein a weight is applied to said signal prior to subtraction from the de-spread signal dependent on said accuracy parameter.

A wireless base station comprising:

• means for receiving a channel request from a mobile terminal;
• means for sending an acknowledgement including an assigned channel to the mobile terminal;
• means for determining an initial channel estimate for the mobile terminal based on the channel request;
• means for receiving data from the requesting mobile terminal using said assigned code and said initial channel estimate;
• means for determining the relative transmission timing of the mobile terminal;
• means for determining a cross-correlation parameter associated with the requesting mobile terminal assigned code and transmission timing and another mobile terminal communicating with the base station and having another code and transmission timing;
• and
• means for cancelling interference on said received data caused by data received from said other mobile terminal on said other code and other transmission timing, said interference cancellation using the cross-correlation parameter, wherein the means for interference cancelling comprises means for calculating an interference signal associated with the other mobile terminal and means for subtracting this from the received data signal in order to recover the data signal without said interference signal, wherein an accuracy parameter is calculated for the interfering signal,
• wherein a weight is applied to said signal prior to subtraction from the de-spread signal dependent on said accuracy parameter.

A method of operating a base station and comprising:

• receiving a channel request from a mobile terminal;
• sending an acknowledgement including an assigned channel to the mobile terminal;
• determining an initial channel estimate for the mobile terminal based on the channel request;
• receiving data from the requesting mobile terminal using said assigned code and said initial channel estimate;
• determining the relative transmission timing of the mobile terminal;
• determining a cross-correlation parameter associated with the requesting mobile terminal assigned code and transmission timing and another mobile terminal communicating with the base station and having another code and transmission timing;
• and
• cancelling interference on said received data caused by data received from said other mobile terminal on said other code and other transmission timing, said interference cancellation using the cross-correlation parameter,
• wherein cancelling interference comprises calculating interference associated with the other mobile terminal and subtracting said calculated interference from the received data to recover the data without said interference, and
• calculating an accuracy parameter for the interference and applying a weight to the interference prior to subtraction from a de-spread signal dependent on said accuracy parameter.