Consider a spatial multiplexing system with N = 4 transmit and M = 4 receive antennas using QPSK. Also, consider a receiver using interference cancelation and zero-forcing nulling without any ordering. Use Monte Carlo simulations to derive the bit error probability versus the received SNR simulation results. We may call such a system V-BLAST with no ordering. How does it compare with the V-BLAST (ZF nulling) curve in Figure 9.10? How important is ordering in V-BLAST?
