User-to-User Interference Mitigation in Dynamic TDD MIMO Systems with Multi-Antenna Users

TL;DR

Through numerical simulations, it is shown that the proposed novel method for UUI mitigation in dynamic time-division duplex multiple-input multiple-output communication systems with multi-antenna users can significantly improve the spectral efficiency performance in cases of heavy UUI.

Abstract

We propose a novel method for user-to-user interference (UUI) mitigation in dynamic time-division duplex multiple-input multiple-output communication systems with multi-antenna users. Specifically, we consider the downlink data transmission in the presence of UUI caused by a user that simultaneously transmits in uplink. Our method introduces an overhead for estimation of the user-to-user channels by transmitting pilots from the uplink user to the downlink users. Each downlink user obtains a channel estimate that is used to design a combining matrix for UUI mitigation. We analytically derive an achievable spectral efficiency for the downlink transmission in the presence of UUI with our mitigation technique. Through numerical simulations, we show that our method can significantly improve the spectral efficiency performance in cases of heavy UUI.

Figures (4)

• Figure 1: Illustration of the considered DTDD MIMO system. Solid lines represent intended data signals and dashed lines are interference signals.
• Figure 2: Summary of the different phases and tasks performed by the UL and DL users and APs in each coherence interval with our DTDD scheme.
• Figure 3: CDFs of the achievable SEs for our proposed method compared to the baseline scenarios without UUI mitigation and with perfect UUI mitigation.
• Figure 4: The $10\%$-likely, $50\%$-likely, and $90\%$-likely relative SEs of our method with $C=2$ compared to the naïve method, for varying UUI SNRs.

Theorems & Definitions (9)

• Remark 1
• Lemma 1
• proof
• Theorem 1
• proof
• Theorem 2
• proof
• Theorem 3
• proof