Implementation of channel aware scheduling and bit-loading for the multiuser SIMO MAC in a real-time MIMO demonstration test-bed at high data rate

In this paper we discuss a cross layer approach to apply channel aware scheduling for a multi user SIMO multiple access channel. We show how optimum power and rate allocation can be achieved when successive interference cancellation (SIC) and a MMSE receiver is used at the base station. Combining this capacity optimum results with quality of service requirements of the users (e.g. data rate or delay) we analyze the joint optimization problem and propose a suboptimum but applicable scheduling approach which can be implemented already today on real time capable hardware. Different scheduling policies were implemented in the real time MIMO test-bed in our lab. We describe the particular hardware setup for the experiments and present measurement results on various scheduling policies under power and bit error rate constraints with an average up-link spectral efficiency of up to 17 bits/s/Hz with 3 base station antennas.