MIMO system in wireless communication refers to the technique of wireless transmission using multiple transmitte r and receiver antennas. The study focuses on MIMO systems in 230 MHz band in high concurrency environments and gives low complexity solutions based on enhancement at the transmitter side and optimization at the receiver side. The Lattice Base Lumped Simplicity (LLL) algorithm is combined with the V-BLAST ordering mechanism at the transmitter side. Inter-user interference is suppressed by matrix orthogonalization and optimal transmitter layer ordering. At the receiver side, the statistical properties of non-circular signals such as BPSK are mined to systematically derive the extended ZF (EZF) and extended MMSE (EMMSE) detectors. These two detectors effectively separate the signal and interference by constructing the augmented signal model. In a 2×2 MIMO system, the Gergely Simplified + V-BLAST scheme saves about 4-6 dB of transmit power compared to linear precoding at BER=0.01. At 10dB SNR, the LLL+V-BLAST user-reachable rate reaches 7.612bit/s/Hz, which is 1.07 times of the spherical lattice decoding, while its computational complexity is only 54.72% of SD. Under the condition of overload factor β=1.5 and number of antennas 130, the total rate of ML detection is 331 bit/s/Hz.EMMSE reaches 341 after 3 iterations and even exceeds ML.
