Bit detection using code spectrum transform techniques for interference cancellation

A device comprising:

• a. a radio receiver that receives a wireless radio that has been transmitted using code division multiple access techniques and produces a baseband signal therefrom;
• b. a baseband signal processor coupled to the radio receiver, wherein the baseband signal processor:
• i. computes a weight vector aM+1 using auto-regression techniques from samples of the received signal over time, where aM+1=∥ε∥2 (RM+1)−1uM+1, RM+1 is a correlation matrix YM+1(YM+1)H, YM+1 is a matrix representing the received signal at time M+1, uM+1 is a unit vector and ∥ε∥2 is a mean-square prediction error, and computes a power spectral density as a function of the full spreading code matrix from the weight vector to determine correlations among spreading codes used for bits in the received signal;
• and
• ii. identifies from a peak in the power spectral density a spreading code associated with bits present in the received signal for another destination device.

A method in a communication device for estimating spreading codes for other destination devices which are present in a signal that has been transmitted using code division multiple access techniques, and wherein the communication device has knowledge only of its own spreading code, comprising:

• a. receiving said signal at said communication device and generating samples thereof;
• b. computing a weight vector aM+1 using auto-regression techniques from samples of the received signal over time, where aM+1=∥ε∥2 (RM+1)−1uM+1, RM+1 is a correlation matrix YM+1(YM+1)H, YM+1 is a matrix representing the received signal at time M+1, uM+1 is a unit vector and ∥ε∥2 is a mean-square prediction error;
• c. computing a power spectral density as a function of the full spreading code matrix based on the weight vector to determine correlations among spreading codes used for bits in the received signal;
• and
• d. identifying from a peak in the power spectral density a spreading code associated with bits for another destination device present in the received signal.