Joint User Pairing and Precoding in MU-MIMO Broadcast Channel with Limited Feedback

In this paper, we propose a joint user pairing and precoding scheme in MU-MIMO broadcast channel with limited feedback. In the proposed scheme, each user feeds back its preferable precoding vector index and two scalars denoting quantization error and the largest singular value of channel matrix, respectively. Base station (BS) selects the first user who has highest estimated SINR, and generates a unitary precoding matrix based on the first user´s preferred precoding vector. Then, BS selects users one by one. In each step, BS calculates the estimated SINR for each un-selected user, using the generated precoding vector, and then chooses the user with largest estimated SINR. Numerical results verify its effectiveness.