SS-MC-MA Systems with Pilot Symbol Aided Channel Estimation in the Asynchronous Uplink

Spread spectrum multi-carrier multiple access (SS-MC-MA) systems exploit in a similar manner as MC-CDMA systems the advantages of the diversity gain due to the spread spectrum technique and the high bandwidth efficiency due to the orthogonal multi-carrier modulation. However, the main difference is that SS-MC-MA systems use FDMA for the user separation and therefore are less vulnerable to multiple access interference, and thus are especially of interest for the uplink of mobile radio systems. They allow asynchronism between the mobile users. In this paper we investigate the effects of ISI and ICI due to asynchronism in the uplink of an SS-MC-MA system on the performance of pilot symbol aided channel estimation. Moreover, we consider the suitability of power boosting of the pilot symbols to improve the link performance.