Mimo Antennas for a Terrestrial Point-to-Point Wireless Link: From the Optimum Antenna Spacing to a Compact Array

Abstract

Abstract-Multiple-input-multiple-output antennas are investigated for terrestrial point-to-point wireless link. The lack of rich scatters in a terrestrial wireless channel results in an ill-conditioned channel matrix for a long range link with compact arrays, which can cause a high bit error rate. This paper demonstrates that the channel matrix can be improved by carefully selecting the antenna spacing. Unfortunately, an optimum antenna spacing that guarantees a good channel matrix is too large to implement for most long range terrestrial wireless links. On the other hand, a channel capacity study of an 8 × 8 link reveals that multiple antennas do provide more capacity even with small antenna spacing. Constellation multiplexing is then applied to the compact array configuration to solve the unreliable communication problem. In addition, a multilevel maximum ratio combining technique is introduced to improve detection efficiency.

Efficient Antenna Selection Strategy for a Massive Mimo Downlink System

“…When MIMO antennas are considered for a terrestrial wireless channel, lack of rich scatters deteriorates the channel matrix resulting in high bit error rate performance. In a similar scenario considered in [13], the channel matrix is enhanced by properly selecting the appropriate antenna spacing. The improved channel obtained as a result of optimum antenna spacing is too large to be implemented for long range terrestrial wireless links.…”

“…A DAS with limited backhaul for an uplink system with the objective of only sum rate maximization without considering the effects of hardware complexity and fading in downlink is discussed in [12]. An improved channel matrix obtained by appropriate antenna spacing which is unsuitable for a large scale cellular system is discussed in [13]. In [14], highly correlated spatially clustered antennas are not given importance in the antenna selection process.…”