Rong Shyan Chen

US Patent:

6725025, Apr 20, 2004

Filed:

Sep 20, 2000

Appl. No.:

09/665843

Inventors:

Timothy M. Schmidl - Dallas TX
Alan Gatherer - Richardson TX
Xiaodong Wang - College Station TX
Rong Chen - Chicago IL

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04B 106

US Classification:

4552781, 455295, 455296

Abstract:

An improved interference cancellation technique is disclosed. Digital baseband circuitry ( ) includes user and symbol detection circuitry ( ) for performing a Gibbs sampler type of interference cancellation, either embodied in custom hardware ( ) or in software. Random initial guesses for a signal sample (either a symbol or chip) are made for each user. Interference cancellation is performed on a user-by-user basis, using the then-current data decision values for the other, interfering users. A soft data decision is used to derive a probability distribution function for the actual data decision for the sample for the user. A randomly selected value is applied against the probability distribution function to generate the next data decision value for that user, and the process is repeated until convergence. Following convergence, a statistic is used to select a final data decision value for each user, from the set of intermediate data decision values stored in memory.