Optimal pilot pattern design for dynamic spectrum access MIMO multicarrier systems

One of the serious challenges, which hamper application of multiple-input multiple-output (MIMO) multicarrier (MC) transmission systems in the cognitive radio (CR) environments, is the synthesis of reliable pilot signals, which can be used for the CR channel sounding. This paper addresses design of the optimal pilot pattern for MIMO-MC CRs. The principal novelty of this work in contrast to the previous ones is that the proposed solution is optimal from both performance and receiver complexity standpoint. To be more specific, we consider pilot sequence precoding, which leads to the best channel estimation accuracy, ensured by the optimal pilot power distribution and joint estimation of the second-order channel response statistics.