English

DoF Upper Bound on Three-User MISO Broadcast Channel with Two Antennas and Mixed CSIT

Information Theory 2023-06-27 v1 math.IT

Abstract

With delayed and imperfect current channel state information at the transmitter (CSIT), namely mixed CSIT, the sum degrees-of-freedom (sum-DoF) in the two-user multiple-input multiple-output (MIMO) broadcast channel and the KK-user multiple-input single-output (MISO) broadcast channel with not-less-than-KK transmit antennas have been obtained. However, the case of the three-user broadcast channel with two transmit antennas and mixed CSIT is still unexplored. In this paper, we investigate the sum-DoF upper bound of three-user MISO broadcast channel with two transmit antennas and mixed CSIT. By exploiting genie-aided signaling and extremal inequalities, we derive the sum-DoF upper bound as (1α)3/2+9α/4(1-\alpha)3/2 + 9\alpha/4, which is at most 12.5%12.5\% larger than the expected sum-DoF, given by (1α)3/2+2α(1-\alpha)3/2 + 2\alpha. This indicates that the gap may mitigate by better bounding the imperfect current CSIT counterpart.

Keywords

Cite

@article{arxiv.2306.14246,
  title  = {DoF Upper Bound on Three-User MISO Broadcast Channel with Two Antennas and Mixed CSIT},
  author = {Shuo Zheng and Tong Zhang and Shuai Wang and Gaojie Chen and Guoliang Li and Shancheng Zhao and Rui Wang},
  journal= {arXiv preprint arXiv:2306.14246},
  year   = {2023}
}

Comments

This paper has been accepted by IEEE International Conference on Computer and Communication Systems (ICCCS) 2023