Ieee 802.11e

For next generation wireless networks, supporting quality of service (QoS) in multimedia application like
video, streaming and voice over IP is a necessary and critical requirement. Wireless Mesh Networking is
envisioned as a solution for next networks generation and a promising technology for supporting
multimedia application.
With decreasing the numbers of mesh clients, QoS will increase automatically. Several research are
focused to improve QoS in Wireless Mesh networks (WMNs), they try to improve a basics algorithm, like
routing protocols or one of example of canal access, but in moments it no sufficient to ensure a robust
solution to transport multimedia application over WMNs.
In this paper we propose an efficient routing algorithm for multimedia transmission in the mesh network
and an approach of QoS in the MAC layer for facilitated transport video over the network studied.

At the present era, Wireless Local Area Networks (WLANs) are one of the most popular and successful wireless technologies in the world and are being used widely, for instance, at home,
at the office and in public places because of its easy deployment and low cost. A well-known standard for WLAN is IEEE 802.11. Because of the wide use of WLAN technology, there is a high probability that more than one WLAN system belonging to the same standard such as 802.11 or also to different standards is collocated in the same frequency band inside the same geographical area. The problem generally faced by the users of such systems is that transmissions can become slower or connections can be interrupted because of collisions and interference that is created by inefficient sharing of the same spectrum.
Therefore, from the economical and technical point of view, it is necessary to develop a spectrum sharing algorithm so that IEEE 802.11 networks can coexist with competing systems
of the same or different technologies. A suitable way to maintain the coexistence is the centralized HCCA channel access method defined in IEEE 802.11e. This standard, however,
only specifies the signaling for centralized channel access, but not the decision scheme which assigns airtime to the mobile stations. For this reason, the standard is extended in this thesis by a method called Regular Channel Access which is specially tailored to maintain the coexistence between neighboring networks, so that spectrum will be shared efficiently in both homogeneous and heterogeneous coexistence scenarios. In comparison to the legacy Distributed Coordination
Function (DCF) of 802.11, Quality of Service (QoS) will be gained using the Regular Channel Access method. In this thesis, Regular Channel Access is implemented in the openWNS
simulator for investigations. The simulation results show that the spectrum can be shared efficiently using the Regular Channel Access Method increasing the success rate of the packets up to 100%. Moreover, the throughput is increased using this method, and the QoS requirements are met.

One of the key challenges in designing a quality of service (QOS) scheme for IEEE 802.11 wireless LANs (WLANS) is reducing collisions and improving throughput. Existed Adaptive contention windows mechanisms can reduce collisions of all traffic. However, adaptive contention window algorithms cannot guarantee the absolute priority of the high-priority traffic. Especially in the heavy loading, low-priority traffics will introduce unnecessary collisions and cause unsuccessful transmission. Our scheme aims to share the transmission channel efficiently and to provide the absolute differentiated traffic scheme. Relative priorities are provisioned by adjusting the range of the back-off timer of low-priority traffic class taking into account both applications requirements and network conditions. We demonstrate the effectiveness of our solution by comparing with existing approaches through extensive simulations. Results show that our scheme reduces frame delay as well when traffic load is heavy. Furthermore, our scheme is simple and easy to implement.

This paper presents how enhanced Quality of Service (QoS) in IEEE802.11e is achieved by providing traffics with different priorities performing the access to the wireless medium. Particularly, the EDCF set of parameters defines the priorities of the admission control mechanism during the Contention-based Period (CP). This can subsequently be declined to a variation of network dynamicity. Reliability analysis of different traffic classes (video, voice and data), without considering both network topology and node's mobility constraints, is not well appropriate. Being based upon scenarios, our proposed approach reveals how the behaviour of the service differentiation scheme is greatly affected according to the nodes' mobility (position and velocity). Thus, three levels (Low, Medium, and High) of node's speed are discerned. Depending on the Access Aategories (AC's) in QoS Stations (QSAT's), the Wireless LAN has been implemented on various static and dynamic scenarios using NS-2. Performance of EDCF based on the main MAC-layer metrics, such as throughput, End-2-End delay and jitter, is deeply investigated.

With the advent of the Internet of Things (IoT), networks will need to handle so-called big data from a range of new sources including Smart Transportation, Smart Cities, Industrial Internet, and Cyber Physical Systems. Increasingly connected over wireless, these devices will produce and consume data for Machine to Machine (M2M) communication and will share networks with more conventional user-generated data from smartphones and tablets. All of this new traffic will emerge along with users increasingly high expectations for Quality of Service (QoS) in traditional Real Time Communications (RTC). Headed by the Open
Networking Foundation (ONF), Software Defined Networking (SDN) is an emerging network architecture that will hopefully
facilitate such high-bandwidth, dynamic applications with differing QoS requirements. The core concept of SDN is that network control is abstracted away from individual devices
towards centralized computing devices. In this paradigm, network intelligence is centralized in software-based SDN controllers, in effect, rendering the network as a single logical switch. In this paper, we explore how introducing time
awareness in an SDN network can help further optimize QoS.

The main objective of this paper is to propose a novel method for enhancing the Quality of Service (QoS) of multimedia applications in wireless adhoc networks. The enhancement is achieved by implementing a cross layer mapping algorithm, between application layer and Medium Access Layer where Connectionless Light Weight Protocol (UDPLite) is used in transport layer that supports multimedia applications. The Proposed method achieves 17% improvement in reduction of delay and 5% improvement in PSNR as compared to the conventional methods under heavy traffic conditions.

The key performance metrics in wireless sensor networks are both network lifetime and an average time required to report an event reliably. The optimal solution must be taken into account to meet these metrics. Considering energy-latency constraints in sensor networks, we have developed a cluster architecture using mobile agents to detect the yarn break in spinning machine in textile industry. We have used the latency improved MAC layer protocol to access the channel in the cluster and also used energy efficient cluster formation algorithm based on residual energy of the sensor node. This protocol can handle multiple event messages efficiently. And, we mainly focused on simulating the behavior of mobile agents for information retrieval from a wireless sensor network in a event driven and poll driven wireless sensor network model.

For next generation wireless networks, supporting q
uality of service (QoS) in multimedia application l
ike
video, streaming and voice over IP is a necessary a
nd critical requirement. Wireless Mesh Networking i
s
envisioned as a solution for next networks generati
on and a promising technology for supporting
multimedia application.
With decreasing the numbers of mesh clients, QoS wi
ll increase automatically. Several research are
focused to improve QoS in Wireless Mesh networks (W
MNs), they try to improve a basics algorithm, like
routing protocols or one of example of canal access
, but in moments it no sufficient to ensure a robus
t
solution to transport multimedia application over W
MNs.
In this paper we propose an efficient routing algor
ithm for multimedia transmission in the mesh networ
k
and an approach of QoS in the MAC layer for facilit
ated transport video over the network studied.