Performance analysis of different channel estimation techniques with different modulation for VBLAST MMSE MIMO-OFDM system

The main focus of this paper is to study performance of two linear channel estimators, the Least Square Error(LS) and Linear Minimum Mean Square Error(LMMSE) for 2×2 and 4×4 VBLAST MIMO OFDM system with different modulation, BPSK, QPSK, 8QAM and 16QAM as well as with MMSE equalizer at receiver. Channel state information is useful at receiver to remove effect of channel in received signal for efficient recovery of data and at transmitter it is useful to vary modulation order and power allocation according to channel for efficient wireless system. For performance analysis, LMMSE is used instead of Minimum Mean Square Error (MMSE) because of its simplicity as well as it retain MMSE criteria but the constrain is linear.