Subspace based channel estimation with multiple receivers in reuse-1 OFDMA systems - impact on diversity combining and nulling

In this paper, we evaluate the performance of subspace based channel estimation method with multiple receivers in reuse-1 OFDM systems. Users in reuse-1 cellular network will typically see signal to interference ratio (SIR) nearly 0dB on the broadcast pilot subcarriers. Good channel estimation and tracking become very difficult for the interference limited users. The improved channel estimation method adopted in this paper assumes the multipath delay locations of the desired and the interferer channels do not overlap. Exploiting this information, it is possible to define a channel estimator/interpolator with a lower mean squared error compared to the conventional channel estimation techniques. The impact of the improved channel estimation method on the coded bit error rate (BER) performance of reuse-1 OFDM systems with receive diversity is presented through computer simulations.