Theoretical System Capacity of Multi-User MIMO THP in the Presence of Terminal Mobility

This paper investigates the theoretical system capacity of multi-user multiple-input and multiple-output (MU-MIMO) Tomlinson-Harashima precoding (THP) in the presence of terminal mobility. Considering that MU-MIMO generally suffers from transmission performance degradation over time selective fading channels owing to terminal mobility, we incorporate the impact of mobility as well as the modulo loss peculiar to THP into the system capacity analysis. In particular, the multiuser interference (MUI) due to terminal mobility is theoretically derived and included as the undesired component in the mod- Λ channel required for analyzing the effect of the modulo loss. The proposed analysis enables a fair comparison in terms of the system capacity between THP and linear precoding (LP), and demonstrates the superiority of THP over LP in the presence of terminal mobility.