scholarly journals A Novel Packet Aggregation Mechanism for Enhancing VoIP Performance on IEEE 802.11 Wireless Mesh Networks

Author(s):  
Guan-Hsiung Liaw et al.

In 802.11 Wireless Mesh Network (WMN), bandwidth will be wasted much for transferring VoIP flows since each voice frame must contain relatively large amount of protocol data. “Packet Aggregation” mechanism can be applied to merge the voice data of multiple VoIP flows into one frame for transmission. It reduces the waste on bandwidth and increases the maximum number of successful VoIP calls. In addition, the mechanism “MCF controlled channel access” (MCCA) defined in 802.11 standard can be used to obtain better QoS than adopting default EDCA mechanism. In MCCA, mesh stations which wants to transfer VoIP flows can reserve time intervals of the medium for transmission and this reservation will be advertised to their neighbors. It is why MCCA causes less medium contentions than EDCA. In this paper, a mechanism to transfer VoIP flows in IEEE 802.11 WMN by MCCA with packet aggregation scheme is proposed. The effectiveness of the proposed mechanism is shown by simulation results. In addition, the problem named as Routing-Packet Aggregation / De-aggregation-Scheduling optimization problem (abbr. RPADS problem) derived from the proposed mechanism is also studied. A heuristic algorithm for RPADS problem to maximize the total number of supported calls is also proposed.

2012 ◽  
Vol 3 (3) ◽  
pp. 368-374
Author(s):  
Usha Kumari ◽  
Udai Shankar

IEEE 802.16 based wireless mesh networks (WMNs) are a promising broadband access solution to support flexibility, cost effectiveness and fast deployment of the fourth generation infrastructure based wireless networks. Reducing the time for channel establishment is critical for low latency/interactive Applications. According to IEEE 802.16 MAC protocol, there are three scheduling algorithms for assigning TDMA slots to each network node: centralized and distributed the distributed is further divided into two operational modes coordinated distributed and uncoordinated distributed. In coordinated distributed scheduling algorithm, network nodes have to transmit scheduling message in order to inform other nodes about their transfer schedule. In this paper a new approach is proposed to improve coordinated distributed scheduling efficiency in IEEE 802.16 mesh mode, with respect to three parameter Throughput, Average end to end delay and Normalized Overhead. For evaluating the proposed networks efficiency, several extensive simulations are performed in various network configurations and the most important system parameters which affect the network performance are analyzed


2016 ◽  
Vol 2016 ◽  
pp. 1-16
Author(s):  
Pragasen Mudali ◽  
Matthew Olusegun Adigun

Topology Control has been shown to provide several benefits to wireless ad hoc and mesh networks. However these benefits have largely been demonstrated using simulation-based evaluations. In this paper, we demonstrate the negative impact that the PlainTC Topology Control prototype has on topology stability. This instability is found to be caused by the large number of transceiver power adjustments undertaken by the prototype. A context-based solution is offered to reduce the number of transceiver power adjustments undertaken without sacrificing the cumulative transceiver power savings and spatial reuse advantages gained from employing Topology Control in an infrastructure wireless mesh network. We propose the context-based PlainTC+ prototype and show that incorporating context information in the transceiver power adjustment process significantly reduces topology instability. In addition, improvements to network performance arising from the improved topology stability are also observed. Future plans to add real-time context-awareness to PlainTC+ will have the scheme being prototyped in a software-defined wireless mesh network test-bed being planned.


2019 ◽  
Vol 01 (02) ◽  
pp. 103-115
Author(s):  
Durai Pandian M

The spread out of wireless mesh network has made possible the extended range of communication network that are impractical due to environmental changes in a wired access point, these wireless mesh network does not require much competence to set it up as it can be set very fast at a cheap rate, and the conveyancing of messages in it happens by selecting the shortest path, these wireless mesh built-in with irrepressible and invulnerable identities come with an endurance to temporary congestion and individual node failure. This results in an architecture providing a better coverage, flaw indulgent with higher bandwidth compared to other wireless distributed systems. But faces the limitation on power conservation. The battery activated mesh nodes loses their resources on perception, processing and transmission of the data’s, though these batteries or accumulators comes with energy regaining capability still draw backs show up as their nature of energy regaining are unexposed. So the performance analysis of fly wireless network which proposes a uninterrupted wireless mesh networks aims at providing a best measure of performance that is the best quality of service on the meshwork by providing an improved energy gleaning using potency segregation (IGPS) which empowers each node to have self- contained accumulation of energy achieving heightened adaption with energy consumption kept at a minimum. The gross functioning of the proposed is examined on the bases of delay and packet loss to prove the quality of service acquired.


2013 ◽  
Vol 443 ◽  
pp. 440-445 ◽  
Author(s):  
Liang Yu Luan ◽  
Ying Fang Fu ◽  
Peng Xiao ◽  
Ling Xi Peng

In a wireless mesh network, the need for cooperation among wireless nodes to relay each others packets exposes the network to a wide range of security threats. A particularly devastating type of threats is the so-called wormhole attacks. In order to defense against the attack, a type of wormhole attack model and a watch nodes-based wormhole attack detection scheme were presented in this paper. The scheme that is based on the combination of a number of techniques, such as distributed voting, watch nodes based detection and identity-based cryptosystem. Qualitative analysis and simulation show that the wormhole attack detection scheme is more advantageous over the some of the previous schemes in terms of performance and cost.


2008 ◽  
Vol 3 (2) ◽  
pp. 122 ◽  
Author(s):  
Xiaodong Lin ◽  
Xinhua Ling ◽  
Haojin Zhu ◽  
Pin Han Ho ◽  
Xuemin Sherman Shen

Author(s):  
Kun-chan Lan ◽  
Zhe Wang ◽  
Mahbub Hassan ◽  
Tim Moors ◽  
Rodney Berriman ◽  
...  

Wireless mesh networks (WMN) have attracted considerable interest in recent years as a convenient, new technology. However, the suitability of WMN for mission-critical infrastructure applications remains by and large unknown, as protocols typically employed in WMN are, for the most part, not designed for real-time communications. In this chapter, the authors describe a wireless mesh network architecture to solve the communication needs of the traffic control system in Sydney. This system, known as SCATS and used in over 100 cities around the world — from individual traffic light controllers to regional computers and the central TMC —places stringent requirements on the reliability and latency of the data exchanges. The authors discuss experience in the deployment of an initial testbed consisting of 7 mesh nodes placed at intersections with traffic lights, and share the results and insights learned from measurements and initial trials in the process.


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