Optimal Chunk Processing for Multi-User MIMO OFDM Wireless Systems

It has been shown that CSI at the transmitter can significantly improve the performance and reliability of multiple antenna multi-user systems. In MIMO OFDM systems the control overhead and signal processing complexity lead to the definition of time-frequency chunks. For all carriers and at all times in the chunk, the same spatial signal processing is applied. In this paper, we study the optimal signal processing using chunks in multi-user MIMO OFDM systems with respect to sum capacity optimization. At first, the optimal single-user chunk capacity optimization is studied and different optimal and suboptimal approaches are proposed. Then, the extension to the spectral power allocation is analyzed. Finally, the multi-user case is addressed. The results are illustrated by numerical simulations based on the IEEE 802.11n channel model