In this letter, we propose a novel signal detection method for spatially multiplexed multiple input multiple output (MIMO) systems, based on the idea of ordered successive interference cancellation (OSIC). In the proposed method, we try every possible value as the first detected symbol instead of making a decision. Although the proposed method requires slightly increased complexity compared to the conventional OSIC, the proposed method eliminates the error propagation from the first detected symbol, so it offers significantly better error performance compared to the conventional OSIC. We compare the proposed method with previous ML, ML-DFE, QRD-M, MMSE, MMSE-OSIC detection methods in terms of the error performance and the computational complexity, and show that the proposed method offers a good performance-complexity trade-off.

We propose a new broadcast strategy for a multiple-input multiple-output (MIMO) system with N transmit antennas at the transmitter and M≤N single antenna receivers. The proposed method, based on dirty-paper coding (DPC), spatially separates the M users but does not suffer from the power loss of classical spatial division multiple access (SDMA). For the special case of M=N=2 and when the two single antenna receivers are assumed to be co-located, the proposed scheme produces a 2 transmit, 2 receiver antenna MIMO transmission system that doubles the symbol rate of MIMO space-time block code (STBC) systems from one to two symbol per transmission time. It is proved theoretically and experimentally that the proposed scheme provides the same performance level as that of MIMO STBC systems (i.e., the Alamouti scheme) for the first symbol, and the same performance as the Bell labs layered space-time (BLAST) system for the second symbol. When compared to the BLAST system, the proposed scheme has the same symbol rate, but achieves significantly better performance, since it provides 2 level diversity per symbol on the first symbol while the BLAST system does not provide any diversity.