Suboptimal pilot design in NC-OFDM systems

In order to improve the performance of non-continuous orthogonal frequency division multiplexing（NC-OFDM)systems with lower complexity， one suboptimal pilot design is presented minimizing the channel estimation mean square error(MSE)in this paper.Firstly， the non-convex problem of pilot position optimization design is converted by one convex mapping method；then based on this analysis the suboptimal non-uniform pilot positions meeting the cubic function are obtained，and the expression of the optimal pilot power distribution is derived.The simulated results have shown that the proposed suboptimal pilot design can achieve better channel estimation MSE performance， and has an advantage of lower computational complexity compared with the existing pilot design methods.