Closed-Loop Antenna Selection for Wireless LANs with Directional & Omni-Directional Elements

Abstract

Abstract-Throughput and packet error rate are analysed in a home environment for two different 3x3 wireless LAN solutions. A 3x3 EBF approach (using three radio chains) is compared with a reduced cost 2x2 architecture (using two radio chains). In the 2x2 solution the optimum antenna pair is selected from the same set of three antennas at the AP and client. The impact of directional, as well as omni-directional, antenna elements is considered. The spatial and temporal characteristics of the inhome channels are modelled using 3D ray tracing and combined with appropriately orientated complex polarmetric patterns for each antenna element. Physical layer throughput is calculated for all modulation and coding schemes and (for the 2x2 case) all possible antenna combinations using a novel received bit mutual information rate abstraction technique. Results show that antenna number, pattern and orientation all play a key role in determining the performance of an 802.11n system. As expected, 3x3 EBF outperforms the 2x2 solution; however, with optimum antenna selection the performance of 2x2 EBF is competitive, especially when directional antennas are used at low signal to noise ratios. For distant rooms, 3x3 EBF is only 15% better (in terms of throughput) than 2x2 EBF when directional antennas and dynamic antenna selection are applied. 2x2 EBF with omni antennas results in a 45% reduction in throughput (compared with 3x3 EBF).

Evaluating the antenna performance of 802.11n wireless routers in an indoor environment

“…eigen-beamforming or spatial-multiplexing) will be taken into account. This is part of our future work and some initial results can be found in [5] [6].…”

“…The antennas used at the access point (AP) and client influence the perceived channel quality and must be carefully considered. Previous measurements [4] and simulations [5] [6] have shown that different antenna configurations and orientations have a significant impact on performance.…”

Comparing Theoretic Single-User and Multi-User Full-Dimension MIMO Data Throughputs in Realistic City-Wide LTE-A Deployments

“…This technique was fully described in [15] and subsequently used in a number of our Wireless LAN and cellular network studies, for instance [21] and [22]. Without sacrificing accuracy, abstraction is many hundreds of times faster than full bit-level simulation.…”

Impact of BS antenna number and array geometry on single-user LTE-A data throughputs in realistic Macro and Pico cellular environments

“…To perform system level analysis in a computationally efficient and scalable manner, a physical layer abstraction technique RBIR was used to predict the packet error rate (PER) for a given channel realisation across the allocated OFDM subcarriers. This technique was fully described in [13] and subsequently used in a number of our Wireless LAN and cellular network studies [17,18]. Without sacrificing accuracy, abstraction is many hundreds of times faster than full bit-level simulation.…”