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The latest IEEE WLAN 802.11ad standard guarantees the multi giga bit throughput which is highest in the Wireless LAN (WLAN) technology. The system designed for such high performance will pose enough design challenges to make them consume low power. This can however be achieved by adopting low power management and control block in the digital part of the System on Chip (SoC) like Medium Access Control...
In this paper, an analytical framework is developed to study the performance of opportunistic channel bonding in IEEE 802.11 WLANs. Specifically, we consider a WLAN operating on multiple channels shared by both legacy users and IEEE 802.11ac users with channel bonding capability. By capturing the opportunistic channel bonding from the IEEE 802.11ac users in the primary channel and the random access...
One of the main challenges on the next generation local wireless networks lies in providing scalable media access control protocols in order to support the predicted high density. Research results have indicated that the current backoff mechanism is ineffective for dense networks, even more under the foreseen growing charge for the next five years. This paper investigates the proposal of the contention...
Wireless systems have migrated into the automotive domain very fast in the recent years. Car passengers expect to have seamless integration of their consumer electronic devices in their cars. IEEE 802.11 systems are popular for entertainment services inside the car, however due to the fact that IEEE 802.11 use the unlicensed industrial, scientific and medical (ISM) radio bands, the wireless coexistence...
Because of the widespread adoption of mobile devices, many applications have provided support for wireless LAN (WLAN). Under these circumstances, one of the important issues is to provide good quality of service (QoS) in WLAN. For this purpose, Dhurandher et al. improved the distributed coordination function (DCF). In this method, the contention window (CW) is divided into multiple ranges. Each range...
Previously, we proposed the active access-point (AP) configuration algorithm for elastic Wireless Local-Area Network (WLAN) systems using heterogeneous APs. This algorithm activates or deactivates APs depending on traffic demands, assuming that any active AP can use a different channel to avoid interferences among APs. However, the number of non-interfered channels in IEEE 802.11 protocols is limited...
Chaotic deployment of Wireless Local Area Networks (WLANs) in dense urban areas is one of the common issues of many Internet Service Providers (ISPs) and Wi-Fi users. It results in a substantial reduction of the throughput and impedes the balanced distribution of bandwidth among the users. Most of these networks are managed independently and there is no cooperation among them. Moreover, the conventional...
In this paper, QoS characteristics such as TCP throughput is investigated for densely deployed mobile wireless LANs (WLANs). Factors affecting throughput characteristics are discussed and evaluated by using real machines such as smartphones and portable APs. In IEEE 802.11 WLANs, a rate adaptation mechanism controls the transmission rate and one of the dominant factors for QoS. In order to understand...
The fragmentation and aggregation (F&A) algorithm improves the throughput while ensuring the reliability in the MAC layer. To determining the optimal fragment size is a key issue of effectively operating the F&A algorithm. In this paper, the proposed method selects the optimal fragmented frame size and uses aggregation scheme based on various channel conditions. As a result the throughput...
In next generation wireless LAN standard which is called IEEE802.11ax, Orthogonal Frequency Division Multiple Access (OFDMA) random access has been adopted as an uplink multi-user transmission technology. In this paper, we propose an adaptive backoff algorithm for OFDMA random access. Due to the finite service period defined by the standard, random access OFDMA sessions are discontinuous in time which...
The emerging software defined networking (SDN) provides a new paradigm of network management by separating control functionalities from underlying data forwarding hardware to an external controller. SDN provides high flexibility to control the whole network in a unified way. In this paper, we are motivated to study the performance issues of a software defined WiFi network testbed. This testbed consists...
This paper studies the effect of the QoS degradation on WebQoE with personal digital assistant (PDA) by experiment. In the experiment, the authors utilize three types of terminals: PDA, tablet PC and desktop PC; they assess QoE for two actual Web services. The experimental results show that the effect of QoS degradation on QoE with PDA is less than that of a desktop PC for one service. However, for...
In this study we present an idea of dynamic placement of relay robot for throughput enhancement in networked robots. By designating some robots as network relay and controlling position of those in real time, the system of networked robots can achieve higher throughput. An analytic throughput model of the robot networks with relays is established and optimal location of relay robots are derived based...
One of the promising techniques to enhance MAC efficiency is orthogonal frequency division multiple access (OFDMA). Even though OFDMA-based WLAN allows multi-user transmissions, it requires a careful design of resource management particularly in densely deployed WLANs. To address this problem, we propose a two-phase resource allocation (TPRA) algorithm. In TPRA, an access points (AP) determines its...
This work presents a new backoff algorithm, namely Maximum Throughput and Fairness aware Backoff (MTFB), for IEEE 802.11 wireless LANs. The algorithm adaptively adjusts the contention window (CW) size so that the maximum throughput and fairness can be maintained even with large number of active stations (STAs). In mixed environments with the legacy 802.11 devices the algorithm is able to keep the...
IEEE 802.11 Wireless Local Area Networks (WLANs) has become one of the most popular networking environments. With high density WLANs, it causes the interference among access points (APs) and degrades the performance of APs, especially in public area. To solve this problem, we design and implement a Cluster-based Channel Assignment (CCA), a combination of RSS-Aware Channel Selection Module (RCSM) and...
Since mobile terminals such as smartphones are basic information tools for users, their communication performance is always significant. Modern loss-based Transmission Control Protocols (TCP) take aggressive congestion window (CWND) control strategies in order to gain better throughput, but such strategies may cause a large number of packets to be backlogged and eventually dropped at the entry point...
E-exam is often used to evaluate the success of learning process on e-learning system. To maintain the honesty, fairness and accountability of e-exam, security system should be pursued to anticipate a variety of fraud or any threat that may occur during the process of e-exam. This paper identifies the role and type of technologies for securing e-exam. Study on e-exam security that emphasizes the aspects...
This paper provide the performance comparison of the IEEE 802.11n and IEEE 802.11ac Wireless Local Area Network (WLAN). The IEEE 802.11ac protocol currently has been used widely. Network Simulator (NS-3) is used to simulate it. The advantages of the research using Network Simulator are shorter time to explore, low cost and flexibility on scenario developed. Our project analyzes and compares the 802...
The EDCA protocol was designed to enhance the functionality of the IEEE 802.11 WLAN through the introduction of different channel access parameter values for different traffic types. This enables some degree of service guarantee for traffic depending on their QoS requirements. While the improved standard has recommended values for the channel accessing parameters, it does not take into account the...
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