Multiple Wireless Local Area Network Research Articles

A Throughput Analysis Using a Non-Saturated Markov Chain Model for LTE-LAA and WLAN Coexistence

To address the severe spectrum shortage in mobile networks, the 3rd Generation Partnership Project (3GPP) standardized Long Term Evolution (LTE)-License Assisted Access (LAA) technology. The LTE-LAA system ensures efficient coexistence with other existing unlicensed systems by incorporating listen-before-talk functionality and conducting random backoff operations similar to those in the IEEE 802.11 distributed coordination function. In this paper, we propose an analytical model to calculate the throughput of each system in a scenario where a single LTE-LAA system shares an unlicensed channel with multiple wireless local area network (WLAN) systems. The LTE-LAA system is utilized for supplementary downlink transmission from the LTE-LAA eNodeB (eNB) to LTE-LAA devices. Our proposed analytical model uses a Markov chain to represent the random backoff operations of the LTE-LAA eNB and WLAN nodes under non-saturated traffic conditions and to calculate the impact of the clear channel assessment (CCA) performed by the LTE-LAA eNB. Through numerical results, we demonstrate how the throughput of both the LTE-LAA and WLAN systems is determined by the contention window size and CCA threshold of the LTE-LAA eNB.

DFOPS: Deep-Learning-Based Fingerprinting Outdoor Positioning Scheme in Hybrid Networks

Many Internet-of-Things (IoT) services rely on location information. This article proposes a deep learning-based fingerprinting outdoor positioning scheme ( $D_{\mathrm{ FOPS}}$ ) for use in scalable environments. The proposed scheme is a hierarchical combination of the support vector machine (SVM) and long short-term memory (LSTM) algorithms. It was applied in a large-scale wireless environment with multiple wireless local area networks (WLANs) and cellular base stations. The results show that the positioning error of the proposed scheme is 42 cm, and the computation time is reduced by 63% compared with conventional methods. Thus, the proposed system can provide promising and reasonable support location-aware services for IoT devices in large-scale wireless environments.

Virtual Reality-Wireless Local Area Network: Wireless Connection-Oriented Virtual Reality Architecture for Next-Generation Virtual Reality Devices

In order to enhance the user experience of virtual reality (VR) devices, multi-user VR environments and wireless connections should be considered for next-generation VR devices. Wireless local area network (WLAN)-based wireless communication devices are popular consumer devices with high throughput and low cost using unlicensed bands. However, the use of WLANs may cause delays in packet transmission, owing to their distributed nature while accessing the channel. In this paper, we carefully examine the feasibility of wireless VR over WLANs, and we propose an efficient wireless multiuser VR communication architecture, as well as a communication scheme for VR. Because the proposed architecture in this paper utilizes multiple WLAN standards, based on the characteristics of each set of VR traffic, the proposed scheme enables the efficient delivery of massive uplink data generated by multiple VR devices, and provides an adequate video frame rate and control frame rate for high-quality VR services. We perform extensive simulations to corroborate the outstanding performance of the proposed scheme.

Analysis of Dynamic Channel Bonding in Dense Networks of WLANs

Dynamic Channel Bonding (DCB) allows for the dynamic selection and use of multiple contiguous basic channels in Wireless Local Area Networks (WLANs). A WLAN operating under DCB can enjoy a larger bandwidth, when available, and therefore achieve a higher throughput. However, the use of larger bandwidths also increases the contention with adjacent WLANs, which can result in longer delays in accessing the channel and consequently, a lower throughput. In this paper, a scenario consisting of multiple WLANs using DCB and operating within carrier-sensing range of one another is considered. An analytical framework for evaluating the performance of such networks is presented. The analysis is carried out using a Markov chain model that characterizes the interactions between adjacent WLANs with overlapping channels. An algorithm is proposed for systematically constructing the Markov chain corresponding to any given scenario. The analytical model is then used to highlight and explain the key properties that differentiate DCB networks of WLANs from those operating on a single shared channel. Furthermore, the analysis is applied to networks of IEEE 802.11ac WLANs operating under DCB–which do not fully comply with some of the simplifying assumptions in our analysis–to show that the analytical model can give accurate results in more realistic scenarios.

Compact Cascaded-Spiral-Patch EBG Structure for Broadband SSN Mitigation in WLAN Applications

A compact cascaded-spiral-patch electromagnetic bandgap (CSP-EBG) structure for wideband simultaneously switching noise suppression is proposed. Instead of using double open stubs to provide dual-band noise suppression for a wireless local area network (WLAN), the proposed CSP-EBG structure offers an even wider bandgap, covering multiple adjacent WLAN bands from 2.4 to 6 GHz. A 1-D equivalent circuit model is proposed and validated by full-wave simulation and measurement. The circuit model could also be adopted to investigate design concepts, optimizing the EBG design by the theory of stepped-impedance resonator. The stopband of the proposed EBG structure covers a frequency range from 2.4 to 6.4 GHz with 91% fractional bandwidth (FBW). It not only provides three times wider FBW than single and double open stubs EBG but also occupies 95% smaller unit-cell size than double open stubs EBG and four times smaller than the mushroom EBG.

Mitigating anomalous measurements for indoor wireless local area network positioning

Indoor positioning methods using location-sensitive features of available wireless signals can achieve high accuracy. In particular, many state-of-the-art methods exploit quite unique sets of location-dependent received signal strength (RSS) measurements from multiple wireless local area network (WLAN) access points (APs), also called as wireless fingerprints. However, reception of signals from WLAN APs is not often stable, and RSS measurements tend to be unavailable due to WLAN card or AP transient effects, limited sensitivity of WLAN cards, and fluctuating attenuation and reflection of signals due to a multipath environment, structural changes and moving objects. In certain hostile scenarios, bogus APs may be installed to disorient WLAN localisation algorithms. In this study, two approaches are proposed to mitigate the impact of faulty signal strength measurements. Performance figures are provided for both simulated and empirical environments in order to support conclusions.

Performance Analysis of Hybrid Wireless Networks Under Bursty and Correlated Traffic

Wireless local area networks (WLANs) have risen in popularity for in-car networking systems that are designed to make driving safer. Wireless mesh networks (WMNs) are widely deployed to expand the coverage of high-speed WLANs and to support last-mile connectivity for mobile users anytime and anywhere at low cost. Many recent measurement studies have shown that the traffic arrival process in wireless networks exhibits the bursty and correlated nature. A new analytical model is developed in this paper as a cost-effective performance tool to investigate the quality-of-service (QoS) of the WMN that interconnects multiple WLANs in the presence of bursty and correlated traffic. After validating its accuracy via extensive simulation experiments, the analytical model is then used to investigate the performance of the hybrid wireless networks.

Performance modelling and optimization of integrated wireless LANs and multi‐hop mesh networks

AbstractThe increasing demand for the coverage of high‐speed wireless local area networks (WLANs) is driving the installation of a very large number of access points (APs). Wireless mesh networks (WMNs) have emerged as a promising technology in the next generation networks to provide economical and scalable broadband access to wireless interconnection of multiple APs that manage individual WLANs in order to extend the coverage of the conventional single WLANs. In this paper, we develop a new analytical model to investigate the quality‐of‐service (QoS) performance metrics in WMNs interconnecting multiple WLANs. The model takes the phenomenon of communication locality into consideration. Extensive simulation experiments are conducted to validate the accuracy of the analytical model. The proposed model is then used to obtain the maximum achievable throughput, which is a key performance metrics in wireless networks. Moreover, we utilize the model to evaluate the impact of communication locality on network performance and investigate its effects on the optimization of integrated WLANs and multi‐hop mesh networks. Copyright © 2009 John Wiley & Sons, Ltd.

Multi-domain WLAN load balancing in WLAN/WPAN interference environments

The proliferation of wireless local area network (WLAN) deployments in enterprises, public areas, and homes will likely cause frequent geographical coverage overlap among multiple networks. A recent growing interest is the coordination among WLAN providers for efficient network management over a large coverage area. While radio resource management for a single WLAN has been studied extensively, little research work addresses resource management over multiple domains. When multiple WLANs co-locate in a small geographic vicinity, the lack of cooperative multi-domain resource management can cause significant performance degradation due to inter-domain interference. Unbalanced loads among multiple networks can incur congestion in a few WLANs while foregoing unused excess resources in others. Moreover, since WLANs often operate in unlicensed frequency bands shared by various public and private networks, they must cope with the dynamic RF environment involving a diverse set of interference sources. This paper introduces a new cooperative load balancing framework for multi-domain WLANs operating in an interference environment. A third-party-based architecture is proposed to facilitate fair radio resource allocation among multiple networks. The proposed third-party agent collects observed network state information from different WLANs and optimizes resource usage. Under the proposed scheme, resource utilization and co-channel interference can be adaptively balanced across the entire integrated system. The impact of other co-located interference sources in the operational environment are taken into account in the optimization process. The proposed load balancing framework for interference environments is a complement to the interference mitigation mechanisms operated at the PHY/MAC layer. Simulation results show that the proposed multi-domain load balancing scheme outperforms other schemes which do not consider interdomain interference or environmental interference.