Interference cancellation method, and receiver
View Patent ↗An interference cancellation method and a receiver operating according to the method, in which multiple access interference cancellation of a received signal is performed and a confidence coefficient for estimates obtained from the received signal is calculated. In order to effect a reliable interference cancellation, the receiver utilizes the calculated confidence coefficients to control the multiple access interference cancellation.
1. A method for canceling signal interference in a TDMA data transmission system, comprising:
calculating estimates of interfering signals in the TDMA data transmission system;
subtracting the estimates of the interfering signals from a desired signal;
calculating a confidence coefficient in a soft-output channel decoder in the TDMA data transmission system, the confidence coefficient having a value in a range greater than 0 and less than 1, for the estimates of the interfering signals based on a received signal;
forming an estimate of each interference signal as a product of a channel estimate and output of the soft-output channel decoder;
subtracting the formed estimates from the received signal;
dividing received signals into several groups in a receiver, each group comprising at least two signals; and
carrying out in each group simultaneous detection of the signals from a received transmission;
wherein each group is detected consecutively;
wherein the signals of groups already detected are regenerated and subtracted from the received transmission prior to detecting a subsequent group;
wherein the signals detected prior to the subtraction from the received transmission are weighed by a confidence coefficient calculated for each received signal.
2. A receiver of a TDMA data transmission system, comprising:
means for carrying out multiple access interference cancellation for a received signal in the TDMA data transmission system;
means for calculating a confidence coefficient in a soft-output channel decoder in the TDMA data transmission system, the confidence coefficient having a value in a range greater than 0 and less than 1, for estimates of the received signal;
means for calculating confidence coefficients for estimates of interfering signals;
means for forming an estimate of each interference signal as a product of a channel estimate and output of the soft-output channel decoder;
means for dividing received signals into several groups, each comprising at least two signals;
means for carrying out, in each group, a simultaneous estimation and detection for the signals from a received transmission and for consecutive detection of each group;
means for regenerating the signals of groups already detected and for weighing the signals already detected by a confidence coefficient calculated for each of the received signals;
means for subtracting the weighted estimates from the received signal; and
means for subtracting the signals of groups already detected from the received transmission prior to detection of a subsequent group.
3. A receiver of a TDMA data transmission system, comprising:
a multiple access interference cancellation mechanism to carry out multiple access interference cancellation for a received signal in the TDMA data transmission system;
a confidence coefficient calculating mechanism to calculate a confidence coefficient in a soft-output channel decoder in the TDMA data transmission system, the confidence coefficient having a value in a range greater than 0 and less than 1, for estimates of the received signal;
a utilizing mechanism to utilize the confidence coefficient calculating mechanism to calculate confidence coefficients for estimates of interfering signals;
a forming mechanism to form an estimate of each interference signal as a product of a channel estimate and output of the soft-output channel decoder;
a signal dividing mechanism to divide received signals into several groups each of which comprises at least two signals;
a signal estimating and detecting mechanism to carry out in each group a simultaneous estimation and detection for the signals from a received transmission and to consecutively detect each group;
a signal regenerating and weighing mechanism to regenerate the signals of groups already detected and to weigh the signals already detected by a confidence coefficient calculated for each of the received signals;
a signal subtracting mechanism to subtract the signals of groups already detected from the received transmission prior to detection of a subsequent group; and
a subtracting mechanism to subtract the weighted estimates from the received signal.