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In a multichannel wireless system, the performance of a link depends on many factors. The link quality is subject to temporal, spatial and spectral diversity, i.e. the SNR is time varying, link-dependent and channel-dependent. In addition, the performance also depends on MAC dynamics and the degree of congestion present in the channel. As a result, different links can experience different performance...
In wireless LANs, MAC protocols perform one of the most important tasks: efficiently sharing the limited bandwidth among the contending stations. In IEEE 802.11, Distributed Coordination Function (DCF) is used as a default MAC protocol. Despite its wide acceptance, it has two major downsides: i) Channel idle time and ii) Collision overheads. Besides, the use of the explicit ack frames incurs extra...
Interference management (RF management) remains one of the main challenges facing the design and deployment of large-scale WLAN. RF management involves the detection, estimation and control of power level, channel allocations and link schedules, to improve the performance of the wireless network. Among interfering links, one can find different types of dependencies. While some of these types can be...
In mature wireless LAN (WLAN) deployments, we show that introducing 802.11ac could have little benefit compared to existing 802.11n deployments. Using a testbed with common characteristics for a WLAN deployment, we compare throughput for 802.11ac and 802.11n (in both 5GHz and 2.4GHz bands). We find that 802.11ac has lower throughput than for 802.11n for our testbed configuration. We also provide an...
Handheld and non-handheld devices, which are simultaneously online, constitute the regular clients of the campus wireless local area networks (WLAN). It is necessary to understand the patterns of the user distribution and the user behavior, and adopt better strategies to optimize the service, as well as to understand the students' daily life. This paper introduces a approach of understanding how campus...
Public areas, such as train stations and airports, providing wireless Local Area Network (WLAN) services are increasing and expanding because of the rapid development of WLANs based on IEEE 802.11 standard. Moreover, because of the advances in smartphone tethering technology, portable access points (APs) such as mobile Wi-Fi routers are being utilized more frequently. Consequently, there are increasing...
The combination of multiple-input multiple-output (MIMO) and orthogonal frequency-division multiplexing (OFDM) is a promising solution for high-data-rate transmission. An architecture of a K-best based list sphere detector (LSD) algorithm for a MIMO-OFDM system is introduced in this paper. The architecture was designed for a 2 × 2 antenna system with quadrature phase shift keying (QPSK) and 16-quadrature...
Radio communication in the millimeter-wave (mmwave) frequency bands, recently standardized by the IEEE 802.11ad specification, is emerging as an alternative to the traditional 2.4/5GHz wireless systems, promising multi-Gigabit throughput. Most work in this area until now has focused on PHY/MAC layer design. In contrast, little attention has been paid towards transport layer performance. In this work,...
In this work, we argue against the common belief that millimeter-wave (mmwave) technology is not a viable option for building general purpose indoor WLANs due to the high directionality and susceptibility to blockage of 60GHz links. Our initial experiments, with commodity 802.11ad hardware, present a very encouraging picture, as far as range and blockage by commonly found materials in indoor WLAN...
Wireless mesh network (WMN) has been proposed to extend wireless coverage by using multi-hop communication to enable network service for mobile devices via densely deployed mesh APs. While modern wireless devices are capable of using multiple WiFi interfaces, the Multipath TCP (MPTCP) protocol has been employed to make full use of the capacity of multiple radios. A key question of MPTCP communication...
The CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) based wireless protocol ensures that each node in the network gets a reasonably fair share (FS) of the network channel. In the distributed environment of wireless network, a malicious node may deliberately select a smaller backoff timer to gain an unfair share of the network channel, thus disrupting the network throughput. This nature...
This paper presents hardware implementations for Improved Wired Equivalent Privacy (IWEP) and RC4 ("Ron's Cipher #4") encryption algorithms. IWEP is a block algorithm providing light-strength encryption. The algorithm has been designed for a new Wireless Local Area Network (WLAN), called TUTWLAN (Tampere University of Technology Wireless Local Area Network). On the contrary RC4, developed...
The size of data exchanged via the Internet and the number of Wi-Fi devices have been increasing, and the amount of data traffic will continue to increase in the future. Thus, ensuring the communication capacity of wireless LANs is one of the most important issues. By reducing communication coverage of each wireless LAN access point (AP) and densely deploying APs, it is possible to improve the communication...
Heterogeneous wireless systems such as a combination of mobile broadband wireless access (MBWA) and wireless local area network (WLAN) are candidates to attain the large capacity in the next generation mobile communication systems. For capacity expansion, small cells of multiple wireless network are deployed densely in these systems. Because a number of the cells overlap, users must discover a lot...
We have proposed a concept of a new Quality of Experience (QoE) oriented wireless local area network (WLAN) on which many applications can run with sufficient quality even in congested environment. The proposed system is designed by taking users’ QoE as a key metric. In this paper, we propose a practical functional flow featuring a new channel access control scheme based on loadable capacity prediction...
A ubiquitous tourist system provides information and services available at tourist spots to the tourists unobtrusively. The information need to be provided in personalized way suitable to tourists with different requirements. To enable such efficient way of information provision, we need to consider the QoS requirements of the application and maintain it with the changing context of the tourist by...
TCP was originally designed for wired communication. Internet was accessed with the help of Ethernet LAN giving the ability to share the same network between many users. In today's world due to the advancement of technologies, wireless LAN is becoming a preferred criterion for communication between many users. In many countries, hotspots are being created for providing free Wi-Fi service. However,...
Wireless Local Area Networks (WLANs) communication means gained widespread reception in recent years and widely used all over world due to its wireless fidelity feature with high data rates assets. With emerged multimedia application on wireless networks and the integration with other cellular networks, requires support for quality of service. In this paper, performance optimization of DCF based IEEE...
Multi-Packet Reception (MPR) technology helps in increasing throughput of Wireless Local Area Networks (WLANs) significantly by allowing multiple nodes to transmit even in the presence of ongoing transmissions in the wireless medium. Instead of discouraging overlapping transmissions as in 802.11 Distributed Coordinated Function (DCF) Medium Access Control (MAC), the proposed MAC layer must facilitate...
With the increasing demand of the high quality service applications the 802.11 WLAN (Wireless Local Area Network) performance becomes the important issue. This paper proposes a Channel Management Algorithm to enhance the network performance by balance the load on access points (APs) to maximize the efficiency of available channels. By managing network channels the overall throughput gets maximized...
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