Conventional Wireless Local Area Network Research Articles

Research on end-to-end secure rerouting and switching protocols for multi-domain communication in wireless LANs

Abstract In response to the escalating demands of wireless local area network (WLAN) users for enhanced network transmission quality, this study explores the optimization of a multi-domain communication system within WLANs. By applying cross-layer technology, we optimize WLAN routing protocols and address end security issues through re-routing and handshake protocol-based solutions. Empirical analysis reveals that our multi-domain communication system outperforms traditional systems, with a 0.28s reduction in delay, a 3.6% to 4.5% decrease in transmit channel utilization, a 2.7% to 3.3% reduction in receive channel utilization, and a queue response time improvement of 0.05 to 0.072s. This research not only demonstrates the superiority of the WLAN multi-domain communication system and End Secure Interaction Protocol over conventional WLAN systems but also provides a viable approach to significantly enhancing WLAN quality.

A Hybrid Intelligent Simulation System for Building IoT Networks: Performance Comparison of Different Router Replacement Methods for WMNs Considering Stadium Distribution of IoT Devices.

As the Internet of Things (IoT) devices and applications proliferate, it becomes increasingly important to design robust networks that can continue to meet user demands at a high level. Wireless local area networks (WLANs) can be a good choice as IoT infrastructure when high throughput is required. On the other hand, wireless mesh networks (WMNs), which are WLANs with mesh topology following the IEEE802.11s standard, have many advantages compared to conventional WLANs. Nevertheless, there are some problems that need solutions. One of them is the node placement problem. In this work, we propose and implement a hybrid intelligent system that solves this problem by determining the position of mesh nodes by maximizing the mesh connectivity and the coverage of IoT devices. The system is based on particle swarm optimization (PSO), simulated annealing (SA), and distributed genetic algorithm (DGA). We compare the performance of three router replacement methods: constriction method (CM), random inertia weight method (RIWM), and rational decrement of Vmax method (RDVM). The simulation results show that RIWM achieves better performance compared to CM and RDVM because it achieves the highest connectivity while covering more clients than the other two methods.

A WLAN Uplink Collision-Resolving Scheme Using Multi-User Beamforming Technique

To effectively improve the throughput of the IEEE contention-based wireless local area network (WLAN) system, many uplink medium access control layer (MAC) protocols based on multi-user multiple-input multiple-output (MU-MIMO) technology have been proposed. However, a common problem of these approaches is that many physical layer (PHY) operations, e.g., synchronization, are not considered. As a result, existing methods may find difficulties in real-world implementation. In this article, we propose a simple yet practical uplink scheme for systems with multiple antennas. The main idea is to conduct multi-user beamforming (MU-BF) at an access point such that it can resolve collided signals from multiple competitive users; the proposed scheme can effectively reduce the upstream collision probability and improve system throughput. The other distinct advantage of the proposed scheme is that the MAC protocol of the original IEEE 802.11 standard, i.e., distributed coordination function (DCF), can remain unchanged. The mathematical analysis of system performance is also presented and verified. Simulations show that the proposed scheme significantly outperforms conventional WLAN systems.

A Hybrid Link-TDMA MAC Protocol for Conventional and Radio over Fiber WLANs

During the last two decades, the IEEE 8201.11 family has multiplied data rate transmissions in wireless local area networks (WLANs). This progress is based on the adoption of new technologies concerning physical layer (PHY), combined with the enhancements in the medium access control (MAC) layer. Radio over Fiber (RoF) is a technology which can further extend this progress, combining the benefits of optical fiber and wireless networks. The current IEEE 802.11 MAC protocol is contention based, which leads to low utilization of the RoF PHY data rate and on the other hand cannot handle the effects of long propagation delays in RoF networks. In this paper, we present a new Hybrid Link Time Division Multiple Access (HL-TDMA) MAC protocol which addresses the above shortcomings and enhances the performance of both conventional and RoF WLANs. Then, through simulation, we evaluate the performance of the proposed protocol, which is shown to be superior to relevant RoF WLAN protocols in the literature.

Backbone-Assisted Wireless Local Area Network

This article presents a cross-layer design of backbone-assisted wireless local area network (WLAN) for dense WLAN deployment. The popularity of 802.11-based WLANs leads to dense WLAN deployment in geographically limited space, including dense access points (AP) and dense users. With dense APs, an AP could overhear packets destined for other APs. Backbone-assisted WLAN is a new system architecture where cooperative APs share the overheard packets through a backbone network, thereby reducing packet retransmission and improving system throughput. Conventional WLAN, such as Wi-Fi, uses Stop-and-Wait ARQ. This article argues that Stop-and-Wait does not work well with backbone-assisted WLAN because of large backbone delays. We first show that with a variant of Selective Repeat ARQ tailored for backbone-assisted WLAN, a single-user backbone-assisted WLAN system can achieve substantial throughput improvement over that with Stop-and-Wait ARQ. Then, we put forth a new system architecture targeted for dense users, referred to as network-coded backbone-assisted WLAN, in which multiple users are allowed to transmit simultaneously. A distinguishing feature of this system is the joint use of physical-layer network-coding (PNC) decoding and multiuser decoding (MUD) in multipacket reception. This article is the first attempt to design an ARQ for multiuser backbone-assisted WLAN. Our overall system design solves a PNC sequence obfuscation problem and addresses long packet latency in Selective Repeat ARQ. Experiments on our software-defined radio prototype indicate that network-coded Ethernet-backbone-assisted WLAN can achieve high system throughput and low packet latency. Specifically, the system throughput can outperform an MUD-only multiuser WLAN and a single-user WLAN by 60 and 100 percent, respectively. Overall, we believe that network-coded backbone-assisted WLAN is a viable solution for boosting throughput and reducing latency in dense WLAN environments.

A WLAN triage testbed based on fuzzy logic and its performance evaluation for different number of clients and throughput parameter

Many devices communicate over Wireless Local Area Networks (WLANs). The IEEE 802.11e standard for WLANs is an important extension of the IEEE 802.11 standard focusing on Quality of Service (QoS) that works with any PHY implementation. The IEEE 802.11e standard introduces Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). Both these schemes are useful for QoS provisioning to support delay-sensitive voice and video applications. EDCF uses the contention window to differentiate high-priority and low-priority services. However, it does not consider the priority of users. In this paper, in order to deal with this problem, we propose a Fuzzy-based Admission Control System (FACS). We implemented a triage testbed using FACS and carried out an experiment. The experimental results show that the number of connected clients is increased during Avoid phase, but does not change during Monitoring phase. The experimental results show that the implemented testbed performs better than conventional WLAN.

A WLAN triage testbed based on fuzzy logic and its performance evaluation for different number of clients and throughput parameter

Many devices communicate over Wireless Local Area Networks (WLANs). The IEEE 802.11e standard for WLANs is an important extension of the IEEE 802.11 standard focusing on Quality of Service (QoS) that works with any PHY implementation. The IEEE 802.11e standard introduces Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). Both these schemes are useful for QoS provisioning to support delay-sensitive voice and video applications. EDCF uses the contention window to differentiate high-priority and low-priority services. However, it does not consider the priority of users. In this paper, in order to deal with this problem, we propose a Fuzzy-based Admission Control System (FACS). We implemented a triage testbed using FACS and carried out an experiment. The experimental results show that the number of connected clients is increased during Avoid phase, but does not change during Monitoring phase. The experimental results show that the implemented testbed performs better than conventional WLAN.

Prototype of IEEE 802.11af-Based Baseband IC Enabling Compact Device for Wireless Local Area Network Systems in TV White-Spaces

In this paper, we present the world’s first prototype of the IEEE 802.11af-based baseband (BB) integrated circuit (IC) enabling compact, low power consumption and even low cost TV white-space (TVWS) devices. Although it has been already over three years since the IEEE 802.11af was standardized in December 2013 as a wireless local area network (WLAN) system utilizing the TVWS, the IEEE 802.11af-based system has not been commercially deployed yet due to difficulties in downsizing, power saving, cost reduction, etc. As well as conventional WLAN systems, an integration of the BB signal processing circuits is one of the promising technologies that can resolve these concerns. The prototype BB IC incorporates IEEE 802.11af physical layer and low-medium access control functions, buffer memories, and interface circuits, thus enabling easy installation, and easy control by connection to a host device via the universal serial bus interface. In addition, we also develop the compact radio frequency (RF) front-end circuit with variable circuits and filters based on the direct conversion scheme by using an off-the-shelf RF IC. By incorporating the prototype BB IC and the RF front-end circuit, we successfully prototype compact card-type TVWS devices in all-in-one package including an antenna. The practicality of the prototype BB IC is demonstrated by characterizing the card-type TVWS devices in respect to transmission and reception performance and throughput.

Fingerprint indoor positioning algorithm based on affinity propagation clustering

AbstractRecently, the fingerprint-based wireless local area network (WLAN) positioning has gained significant interest. A probability distribution-aided indoor positioning algorithm based on the affinity propagation clustering is proposed. Different from the conventional fingerprint-based WLAN positioning algorithms, the paper first utilizes the affinity propagation clustering to minimize the searching space of reference points (RPs). Then, we introduce the probability distribution-aided positioning algorithm to obtain the target's refined position. Furthermore, because the affinity clustering can effectively lead to a reduction of the computational cost for the RP searching which is involved in the probability distribution-aided positioning algorithm, the proposed algorithm can lower the difficulty and minimize the power consumption when estimating the user's position. Experimental results conducted in the real environments show that our proposed algorithm will significantly improve the performance of the probability distribution-aided positioning algorithm in both the positioning accuracy and real-time ability.

Dynamic Transmission Power Control Mechanism for Maximizing Energy Efficiency of WLAN

Energy efficiency is not fully considered as the key factor compared with coverage and interference in the conventional wireless local area network (WLAN) deployment phase in the past. However, energy consumption is increasing exponentially with the heavy growing number of mobile nodes (MN). As a result, excessive use of energy is becoming a serious problem even a disaster in multi-base-station WLAN. In this paper, a mechanism of transmission power configuration in WLAN deployment and dynamic transmission power control during WLAN running phase is proposed focusing on the energy efficiency and coverage. The performance of the mechanism has been experimentally evaluated at the system level and system-wide power usage on the demonstration testbed.

Layer 3 wireless mesh networks: mobility management issues

Wireless Mesh Networks (WMNs) may be broadly classified into two categories: Layer 2 and Layer 3 WMNs. This article focuses on the Layer 3 WMN, which provides the same service interfaces and functionalities to the conventional mobile host (MH) as the conventional wireless local area network. Three essential design issues to realize seamless mobility management in the Layer 3 WMN are identified and systematically discussed in this article. They are IP address resolution, location management, and Media Access Control (MAC) address resolution. The Layer 3 WMN backbone requires systematic management of the IP and MAC addresses of each MH, which can be realized by four basic approaches: centralized management, home management, replication management, and distributed management. It is shown that the address pair management architecture is fundamental to realizing efficient packet forwarding and address resolution. Design guidelines are provided to realize Layer 3 WMN supporting seamless MH roaming, considering the applicability of address pair management architectures with regard to WMN scale and client mobility; this applicability is considered based on a qualitative evaluation of the management overhead and handover performance.

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.