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In this paper, we study the throughput fairness performance in IEEE 802.11 based wireless local area networks (WLANs) without and with successive interference cancellation (SIC) technique. We consider a single rate WLAN with carrier sense multiple access with collision avoidance (CSMA/CA) medium access control (MAC) protocol for MAC layer and a SIC technique at the physical layer. We determine the...
In this paper, we develop a theoretical throughput estimation method for IEEE 802.11 Wireless Local Area Networks (WLANs), which accurately estimates how much throughput each node would achieve in a WLAN where nodes have different characteristics in terms of traffic demands, transmission rates, and packet sizes. The developed method is applicable to various types of topologies of WLANs including hidden...
For the problems of the unfeasibility of the optical fiber deployment and the inflexibility of the network optimization in the current Distributed Antenna System (DAS) based on Radio over Fiber (RoF) technology, this paper presents a novel wireless network architecture using Radio over Free Space Optics (RoFSO) for wireless local area networks (WLANs). RoFSO not only transmits various kinds of radio...
We present high data rate wideband transceiver design and experimental evaluation for 3.62 Gbps wireless transmission systems in this paper. The present system provides high definition moving picture and contents in a real-time wireless environment at home, offices or class rooms of universities. Also, the present platform provides a test platform for the Giga level high throughput wireless communication...
IEEE 802.15.4 Wireless Sensor Networks (WSNs) share the 2.4 GHz Industrial, Scientific, and Medical (ISM) license-free band with many other wireless technologies such as IEEE 802.11b/g Wireless Local Area Networks (WLANs). Because of the low-power, however, IEEE 802.15.4 WSNs are potentially vulnerable to the interference introduced by the other wireless technologies such as IEEE 802.11b/g WLANs,...
Wireless local area networks (WLANs) provide mobility and convenience to users, the efficiency of today's WLANs are still far from satisfactory. In this paper discusses the performance of wireless Ad-Hoc networks, our main contribution is analyze transmission's power level to compare the throughput performance on simulation results. We describe NS-2 (Network Simulation) implementations for fine-tuning...
We present a centralized integrated approach, ADWISER, for (i) managing an Internet access link bandwidth, and (ii) for enhancing the performance of an IEEE 802.11 WLAN. Our single-box approach is an extension to our previous work, where we focused on meeting TCP performance objectives over WLANs. In this work, we present a novel cascaded packet scheduling algorithm to address the issue of unfair...
The IEEE 802.11e technology is receiving much interest due to the enhancements offered to wireless local area networks in terms of QoS. Other application fields for this technology are wireless ad-hoc networks, wireless mesh networks and vehicular ad-hoc networks. In the literature, most of the research works available focusing on the IEEE 802.11e technology offer simulation results alone, being hard...
In this paper, we consider a wireless communication network for both low-speed mobile nodes in densely populated hotspots and high-speed mobile nodes roaming in a large area. Wireless local area networks (WLANs) are deployed in the hotspots, while a delay/disruption tolerant network (DTN) provides services to roaming nodes in the large area with low node density. We investigate radio resource allocation...
It is well known that in dense mesh networks, CSMA-based MACs such as IEEE 802.11 achieve lower through-put than optimal spatial TDMA. This paper explores the degree to which the difference in throughput is partly due to a lack of channel usage information and the degree to which the difference is due to packet ordering. To this end, the throughput achieved by a large number of hypothetical MAC algorithms...
In conventional IEEE 802.11 medium access control protocol, the distributed coordination function is designed for the wireless stations (WSs) to perform channel contention within the wireless local area networks (WLANs). Packet collision is considered one of the major issues within this type of contention-based scheme, which can severely degrade the network performance for the WLANs. Research work...
In this paper, we analyze the throughput performance of a new access protocol, called Cooperative Access with Relay's Data (CARD) for multi-rate wireless local area networks (WLANs). CARD allows remote source nodes to transmit their information at a higher data rate to Access Point (AP) by using intermediate nodes as relays, particularly, a relay node sends its own data packet after forwarding a packet...
Many new emerging applications involving realtime multimedia communications require sufficient bandwidth, as well as limited delay and minimized packet loss. In special, video streaming, that accounts for a large portion of the traffic in future networks, poses a difficult challenge to wireless networks, due to their strong requirements as well as to the great variability of channel conditions and...
In wireless local area networks (WLANs), the greedy closed loop control nature of TCP and the performance anomaly of wireless channel lead to the up/down and time unfairness problems between TCP flows. To achieve the wireless channel usage time fairness between the uplink and downlink TCP flows, we propose the up/down time fair LAS (UDTFLAS) scheduling algorithm. Taking into account the transmission...
Since most wireless local area networks (WLANs) eventually access a wired backbone network, there is a need to ensure end-to-end quality of service (QoS) in order to support multimedia traffic in WLAN-wired networks. The implementation of QoS at the media access control (MAC) layer in the WLAN, and IP layer in the wired network presents a challenge in enabling seamless and consistent service differentiation...
Analytic performance of IEEE 802.11 distributed coordination function that takes into account hidden node problem and unsaturated traffic condition is presented for symmetric networks. This enables us to estimate the performance of practical wireless local area networks more accurately. It is shown that the presence of hidden nodes barely affects the network performance in low traffic conditions,...
In this paper, we report the first fully bidirectional wireless data transmission of IEEE802.11a Wireless Local Area (WLAN) signals over fibre using uncooled directly modulated lasers thus providing a low cost solution. A successful connection of IEEE802.11a was established between a mobile unit and the remote base station (BS) which in turn was connected via an optical fibre to the wireless access...
A traffic-aware and client-aware algorithm for dynamically assigning channels to access points (APs) in wireless local access networks (WLANs) is proposed. Traffic loads and received signal strength (RSS) values are used to characterize interference. The problem of selecting channels to minimize total interference then reduces to the Max k-Cut problem, which we efficiently solve with semidefinite...
In recent years the interest in supporting voice over IP (VoIP) services over wireless local area networks (WLANs) based on IEEE 802.11 standard is growing. A key issue on this topic is to understand how well the 802.11 can support quality of service (QoS) for VoIP services. Recently ITU-T has released the E-model recommendation to evaluate voice quality perceived by users. In this paper we present...
Null data frames are a special but important type of frames in IEEE 802.11 based wireless local area networks (e.g., 802.11 WLANs). They are widely used for power management, channel scanning and association keeping alive. The wide applications of null data frames come from their salient features such as lightweight frame format and implementation flexibility. However, such features can be taken advantage...
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