Pilots for joint channel estimation in multi-user OFDM mobile radio systems

This paper addresses the issue of pilot design for the purpose of channel estimation in the uplink of a mobile radio system applying OFDM. The pilots are designed based on the performance criteria SNR degradation for noise scenarios and variation coefficient for interference scenarios. Besides the method of randomly generating pilots and the design method based on the disjoint subcarrier approach, a novel method for designing pilots based on Walsh codes is presented in the paper. The pilots resulting from the aforementioned method exhibit a very good performance both in noise and in interference scenarios.