The RSSE receiver with the channel estimator using the path history

For mobile communication systems, the RSSE (reduced state sequence estimation) receiver must be made adaptive to learn and to track the channel parameters. This is achieved by the adaptive channel estimator. But the channel estimator using the tentative decisions has error propagation because of incorrect decisions. This paper presents a new channel estimator using the path history in the Viterbi decoder for preventing error propagation. The selection of the path history depends on the path metric as in the decoding of the Viterbi decoder in the RSSE. A discussion on the channel estimator with different adaptation algorithms such as the least mean square (LMS) algorithm and recursive least square (RLS) algorithm is provided. Results from computer simulations show that the RSSE receivers using the proposed channel estimator have better performance than the other conventional RSSE receiver, and the channel estimator with the RLS algorithm obtains adequate performance.