2 research outputs found
Optimization of MIMO detectors: Unleashing the multiplexing gain
Multiple Input Multiple Output (MIMO) systems have recently emerged as a key
technology in wireless communication systems for increasing both data rates and
system performance. There are many schemes that can be applied to MIMO systems
such as space time block codes, space time trellis codes, and the Vertical Bell
Labs Space-Time Architecture (V-BLAST). This paper proposes a novel signal
detector scheme called MIMO detectors to enhance the performance in MIMO
channels. We study the general MIMO system, the general V-BLAST architecture
with Maximum Likelihood (ML), Zero- Forcing (ZF), Minimum Mean- Square Error
(MMSE), and Ordered Successive Interference Cancellation (SIC) detectors and
simulate this structure in Rayleigh fading channel. Also compares the
performances of MIMO system with different modulation techniques in Fading and
AWGN channels. Base on frame error rates and bit error rates, we compare the
performance and the computational complexity of these schemes with other
existence model.Simulations shown that V-BLAST implements a detection
technique, i.e. SIC receiver, based on ZF or MMSE combined with symbol
cancellation and optimal ordering to improve the performance with lower
complexity, although ML receiver appears to have the best SER performance-BLAST
achieves symbol error rates close to the ML scheme while retaining the
lowcomplexity nature of the V-BLAST.Comment: Journal of Telecommunications,Volume 1, Issue 1, pp1-5, February 201
Minimum BER transmit optimization for two-input multiple-output spatial multiplexing
Abstract — A two-input multiple-output (TIMO) system represents an important special case of multiple-input multipleoutput (MIMO) systems and occurs in practical scenarios where there are limitations on cost and/or space to install more antennas, in MIMO with transmit antenna selection which selects two out of multiple transmit antennas and turns MIMO into TIMO, or in cooperative communications with two singleantenna mobiles sharing their antennas. In this paper, minimum bit error rate (MBER) transmit optimization for TIMO spatial multiplexing systems is investigated. Approximate MBER transmit power allocation for a variety of receiver structures is proposed. Transmit beamforming schemes using 4-ary Pulse-Amplitude-Modulation (4-PAM) and Quaternary Phase-Shift-Keying (QPSK) pre-mixing are also proposed, which eliminate error floors in ill-conditioned TIMO channels. It is shown both analytically and by numerical simulations that the proposed schemes offer superior performance over existing schemes. Essentially, the proposed transmit optimization provides a simple and efficient means to utilize partial channel state information at the transmitter. I