Joint Channel Estimation of Multiple Transmitters on Shared Resource Blocks by Approximating Channel States with Constant Frequency Sinusoids

In this paper, we propose a novel method for the channel estimation of multiple transmitters sharing the same set of Resource Blocks (RB). Our method processes the entire signal and jointly estimates the channel states of different transmitters, thereby achieving higher performance than existing methods. The key novelty is to approximate the channel state vector as the linear combination of complex sinusoids on fixed frequencies, and to optimize the coefficients of the base sinusoids to minimize the approximation error. Our method enjoys low computation complexity because the base sinusoids are on fixed frequencies and many steps can be precomputed. Our method can be applied to LTE MIMO uplink, as well as to 5G Grant Free channels. It is most suited when the number of RBs is small, which has been confirmed by our evaluation.