Millimeter Wave Communications with Reconfigurable Antennas

The highly sparse nature of propagation channels and the restricted use of radio frequency (RF) chains at transceivers limit the performance of millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems. Introducing reconfigurable antennas to mmWave can offer an additional degree of freedom on designing mmWave MIMO systems. This paper provides a theoretical framework for studying the mmWave MIMO with reconfigurable antennas. We present an architecture of reconfigurable mmWave MIMO with beamspace hybrid analog-digital beamformers and reconfigurable antennas at both the transmitter and the receiver. We show that employing reconfigurable antennas can provide throughput gain for the mmWave MIMO. We derive the expression for the average throughput gain of using reconfigurable antennas, and further simplify the expression by considering the case of large number of reconfiguration states. In addition, we propose a low-complexity algorithm for the reconfiguration state and beam selection, which achieves nearly the same throughput performance as the optimal selection of reconfiguration state and beams by exhaustive search.Comment: presented at IEEE ICC 201

BER performance of MIMO system employing fast antenna selection scheme under imperfect channel state information

In this paper, a closed-form expression for Bit Error rate (BER) of a Multiple-Input Multiple-Output (MIMO) system employing the Minimum Mean Square Error MMSE channel estimation method is derived. The numerical results show that when the Channel State Information (CSI) is free of estimation errors BER decreases when the number of receive antennas increases. However under imperfect CSI, BER is getting worse when the number of Rx antennas is increased. In order to improve BER, a fast antenna selection scheme is proposed. The obtained numerical results prove that the proposed antenna selection scheme indeed improves the MIMO system BER performance. ©2010 IEEE

Energy-Efficient Architecture for Receive Spatial Modulation in Large MIMO Systems

Cost and power consumption are substantial challenges for multiple-input-multiple-output (MIMO) wireless communication systems when the number of antennas and the operating carrier frequency increase. We present a low cost and low power consumption receive spatial modulation (RSM) architecture based on a simple receiver design. We propose a time-division-duplex (TDD) transmission protocol aimed to reduce the training overhead where the channel knowledge is required only at the base station. Simulation results presented show that the power consumption and the energy efficiency of the proposed RSM architecture outperform the hybrid and conventional MIMO systems

Deep Fading Effect On an Individual Link of 4× 4 Mimo Communication Systems

The hottest issue of next generation communication systems is data throughput improvement for any wireless channel conditions. Mul-ti-Input Multi-Output (MIMO) systems are the key technology for the next generation communication systems. Bill Lab Layered Space Time (BLAST) system achieves high data rates with acceptable BER performance over a good channels state. However, when the wireless channel has a considerable fading then the performance will be decreased and at a deep-fading state the system may fail to transmit any signal. This paper studies and compares the conventional 4 4 Vertical BLAST system capacity and bit error rate (BER) performance at Maximum Likelihood (ML) receiver through a simulation. It also studies the effect of a transmit link deep-fading on the effective signal to noise ratio, system BER and system capacity in 4 4 VBLAST system in a comparative way with the conventional 4 4, 3 4, 2 4 and 1 4 VBLAST system. Considering that every possible case of transmit link deep fade lower than-20dB fading gain is equivalent to switching off this transmit link an