Distributed Antenna Selection Research Articles

An Adaptive Symmetrical Load Balancing Scheme for Next Generation Wireless Networks

In dense Wi-Fi networks, achieving load balancing is critical to optimize network utilization and provide equitable network consumption among the users. Traditional Wi-Fi networks have issues in attaining effective load balancing. Software-Defined Networking (SDN) has presented a viable solution by isolating the data plane and control plane, enabling more agile and cost-effective networks. In this paper we put forward an Adaptive Symmetrical Load Balancing (ASLB) scheme to ensure fairness of load symmetry in Software Defined Wi-Fi Networks (SD-Wi-Fi), while also optimizing the flows transition process using an Analytical Hierarchal Process (AHP). User activity is monitored by access points (APs), which operate under OpenFlow standards. Three essential features, packet volume, packet category and delay hindrance, are used for flow assignment to various controllers. The controllers are arranged in two tiers, universal and regional controllers. The universal controller (UC) handles the workload statistics of regional controllers (RC) in the form of clusters. Extensive simulations using OMNeT++ simulator are performed. The performance parameters taken into consideration are throughput, delay, packet loss rate, network transition count and workload distribution. Our findings demonstrate that the ASLB technique effectively optimizes the network utilization and ensures equitable network consumption among the end users. The proposed scheme outperforms the Mean Probe Delay scheme (MPD), Channel Measurement-based Access Selection scheme (CMAS), Received Signal Strength Indicator-based scheme (RSSI) and Distributed Antenna Selection scheme (DASA), being 40% higher in throughput and 25% lower in delay.

Distributed Antenna Selection for Massive MIMO Using Reversing Petri Nets

Distributed antenna selection for Distributed Massive MIMO (Multiple Input Multiple Output) communication systems reduces computational complexity compared to centralised approaches, and provides high fault tolerance while retaining diversity and spatial multiplexity. We propose a novel distributed algorithm for antenna selection and show its advantage over existing centralised and distributed solutions. The proposed algorithm is shown to perform well with imperfect channel state information, and to execute a small number of simple computational operations per node, converging fast to a steady state. We base it on Reversing Petri Nets, a variant of Petri nets inspired by reversible computation, capable of both forward and backward execution while obeying conservation laws.

Precise error‐rate performance with distributed antenna selection transmission over Nakagami‐ m fading channels

This study investigates the downlink error-rate performance for a multicell distributed antenna system (DAS) over Nakagami-m fading channels, where arbitrary number of remote antenna units are uniformly deployed within each macrocell. An antenna selection transmission scheme is presented to reduce the power consumption and the number of interfering signals from outside the target macrocell. Unlike most previous studies in which the interference plus noise is assumed to be Gaussian distributed with constant variance, the co-channel interference here is considered as a random variable. The authors first derive a closed-form bit error rate (BER) expression by adopting the commonly used Gaussian-Q-function approximation. Furthermore, consider the desired signal and the interfering signals undergo different fading severities, they derive a precise BER expression in terms of single-integral by applying the characteristic function. For the special case of Rayleigh fading, an exact closed-form BER expression is obtained. Finally, these error-rate expressions which can be evaluated efficiently indicate some significant insights into the characteristics of the antenna selection transmission for DAS. Simulation results are provided to validate their theoretical analysis.

A Novel Distributed Antenna Selection Scheme for Fixed-Gain Amplify-and-Forward Relaying Systems

This paper proposes a novel distributed transmit antenna selection (AS) concept for dual-hop fixed-gain amplify-and-forward (AF) relaying systems, where a multiantenna source transmits information to a single-antenna destination by using a single-antenna half-duplex relay. By invoking a local channel information exploitation/decision mechanism along with decision feedback between terminals, a distributed AS (DAS) scheme is formulated. Compared with the optimal/suboptimal AS, DAS can maintain a low and constant delay/feedback overhead, irrespective of the number of transmit antennas. Moreover, asymptotic outage analysis reveals that DAS can still achieve full diversity order. In addition, it is numerically shown that when the relay is deployed in an outage-optimal manner, DAS can attain very close outage performance to that of the optimal AS.

Resource allocation in downlink OFDMA distributed multipoint systems with incoherent and coherent transmitters

Distributed multipoint systems (DMS) are important and timely for the move to future broadband wireless communication systems. Traditional studies on DMS have mainly focused on the issues with the spatial division multiple access such as precoding techniques, which only consider a narrowband case. This paper addresses the downlink radio resource management of the orthogonal frequency division multiple access DMS (OFDMA-DMS), including power allocation between users or subcarriers, and distributed antenna selection. Signal models with incoherent and coherent transmitters are built. To maximize the system throughput, for the incoherent transmitter case, a strategy based on the iterative water-filling power allocation is proposed to approach the optimality. As for the coherent case, where coherent additions of the signal could occur at the users, the problem is transformed into an integer programming which is solvable. Numerical results show that the gain from the coherent transmitter is promising. And to achieve a near-optimal solution, only part of the DA ports will be used, which have better channel conditions.

Characterization of the Indoor Multiantenna Body-to-Body Radio Channel

In this paper, we investigate the wideband body-to-body radio channel with multiple antennas at both ends based on a time-domain radio channel measurement campaign. Four single-element transmitters and eight quad-element receivers were mounted on three test people. Both directional and omnidirectional antennas have been investigated. A comparison between electromagnetic antenna simulations and the measurements shows that the multipath environment reduces the body losses effectively. Channel characterizations in terms of path loss, body shadowing, small-scale fading, and spatial correlation have been derived. Small path-loss exponents (< 2.0) are observed in the investigated environments. Considerable power loss due to body blockage makes the body shadowing a prominent factor in the short-range body-to-body communications. Distributed antenna selection diversity is presented to mitigate the body shadowing. A 5-dB diversity gain in the average received power at the mean and 10% outage levels have been identified based on the measurements with two distributed antennas mounted on the transmitter and receiver person and without channel-state information feedback to the transmitter.

Adaptive transmitted distributed antenna selection strategy in distributed antenna systems with limited feedback beamforming

An adaptive transmitted distributed antenna (DA) selection strategy in distributed antenna systems (DAS) with limited feedback (LFB) beamforming is proposed. By maximising the upper bound of ergodic capacity in DAS with LFB beamforming, the proposed strategy can adaptively adjust the number of transmitted DAs. Simulation results show that the proposed strategy achieves greater ergodic capacity than the strategy with a fixed number of transmitted DAs.