Transient behavior of the minimum mean-squared error receiver for direct-sequence code-division multiple-access systems

The transient behaviour of an adaptive near-far resistant receiver for DS code division CDMA called minimum mean-squared error receiver MMSE is investigated by considering the length of the training period needed as a function of the number of interfering users as well as the severity of the near far problem. The filter is adapted using a standard LMS algorithm. The tradeoff between convergence and excess mean error is studied. Results show that in most all cases a step size near 1.0 provides the best compromise. In addition, MMSE receiver is capable of tolerating about 30-40dB worth of near-far problem before the convergence time becomes unacceptable.

Transient behavior of the minimum mean-squared error receiver for direct-sequence code-division multiple-access systems Conference Paper