Performance Analysis of VoIP in Multi-Hop Wireless Network

This paper presents the performance evaluation of Voice over Internet Protocol (VoIP) in Multi-hop Wireless Network (MWN) developed using Multi-radio Access Relay (MAR). The MWN is deployed using 3 MARs in Universiti Teknikal Malaysia campus. The performance of VoIP are investigated using Real Time Protocol (RTP) and Compress Real Time Protocol (CRTP) header techniques. RTP and CRTP are used to transport voice packets using G711.1, G723.1 and G729.2 codec. The performance of VoIP is analyzed based on three important elements which are delay, jitter and packet loss

Packet aggregation for voice over internet protocol on wireless mesh networks

>Magister Scientiae - MScThis thesis validates that packet aggregation is a viable technique to increase call ca-pacity for Voice over Internet Protocol over wireless mesh networks. Wireless mesh networks are attractive ways to provide voice services to rural communities. Due to the ad-hoc routing nature of mesh networks, packet loss and delay can reduce voice quality.Even on non-mesh networks, voice quality is reduced by high overhead, associated with the transmission of multiple small packets. Packet aggregation techniques are proven to increase VoIP performance and thus can be deployed in wireless mesh networks. Kernel level packet aggregation was initially implemented and tested on a small mesh network of PCs running Linux, and standard baseline vs. aggregation tests were conducted with a realistic voice tra c pro le in hop-to-hop mode. Modi cations of the kernel were then transferred to either end of a nine node 'mesh potato' network and those tests were conducted with only the end nodes modi ed to perform aggregation duties. Packet ag- gregation increased call capacity expectedly, while quality of service was maintained in both instances, and hop-to-hop aggregation outperformed the end-to-end con guration. However, implementing hop-to-hop in a scalable fashion is prohibitive, due to the extensive kernel level debugging that must be done to achieve the call capacity increase.Therefore, end-to-end call capacity increase is an acceptable compromise for eventual scalable deployment of voice over wireless mesh networks

Call capacity for voice over Internet Protocol on wireless mesh networks

This paper describes work in progress on call capacity optimization for voice over Internet Protocol on wireless mesh networks. In a developing country such as South Africa, evidence has shown that rural inhabitants find it difficult to afford the voice services offered by cellular networks. Voice over Internet Protocol is known for its affordability relative to cellular voice services, therefore deploying such services for rural communities will not only benefit rural inhabitants but also offer economic advantages to service providers. We are interested in the provision of voice services with rural wireless mesh networks. Unfortunately voice on mesh networks can experience packet loss and delays that cause reduction in voice quality. Transmission of small voice packets over wireless mesh networks imposes high overhead that leads to a tremendous decrease in call capacity. Therefore, we aim to study the performance of voice over 802.11 wireless mesh networks and evaluate packet aggregation mechanisms that merge small voice packets into a single large packet, in order to preserve voice quality with more calls. We will implement and evaluate packet aggregations mechanisms on a 'mesh potato' network with iterative cycles of laboratory experiments using a network simulator to collect data for performance evaluation.Telkom, Cisco, THRIPDepartment of HE and Training approved lis

Packet aggregation for voice over internet protocol on wireless mesh networks

>Magister Scientiae - MScThis thesis validates that packet aggregation is a viable technique to increase call capacity for Voice over Internet Protocol over wireless mesh networks. Wireless mesh networks are attractive ways to provide voice services to rural communities. Due to the ad-hoc routing nature of mesh networks, packet loss and delay can reduce voice quality. Even on non-mesh networks, voice quality is reduced by high overhead, associated with the transmission of multiple small packets. Packet aggregation techniques are proven to increase VoIP performance and thus can be deployed in wireless mesh networks. Kernel level packet aggregation was initially implemented and tested on a small mesh network of PCs running Linux, and standard baseline vs. aggregation tests were conducted with a realistic voice traffic profile in hop-to-hop mode. Modifications of the kernel were then transferred to either end of a nine node 'mesh potato' network and those tests were conducted with only the end nodes modified to perform aggregation duties. Packet aggregation increased call capacity expectedly, while quality of service was maintained in both instances, and hop-to-hop aggregation outperformed the end-to-end configuration 4:1. However, implementing hop-to-hop in a scalable fashion is prohibitive, due to the extensive kernel level debugging that must be done to achieve the call capacity increase. Therefore, end-to-end call capacity increase is an acceptable compromise for eventual scalable deployment of voice over wireless mesh networks

On algorithms, system design, and implementation for wireless mesh networks.

Yuan, Yan.Thesis submitted in: November 2007.Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.Includes bibliographical references (leaves 84-87).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 1.1 --- Wireless Mesh Network --- p.3Chapter 1.1.1 --- Architecture Overview --- p.3Chapter 1.1.2 --- Routing Protocols --- p.5Chapter 1.2 --- Contribution of this Thesis --- p.7Chapter 1.3 --- Organization of this Thesis --- p.8Chapter 2 --- Background and Literature Review --- p.9Chapter 2.1 --- VoIP on Wireless Mesh Networks --- p.9Chapter 2.1.1 --- Performance of VoIP on Wireless Mesh Networks --- p.9Chapter 2.1.2 --- Optimizations for VoIP over Wireless Mesh Networks --- p.12Chapter 2.1.3 --- Path and Packet Aggregation Scheme --- p.14Chapter 2.2 --- Network Coding on Wireless Mesh Networks --- p.15Chapter 2.2.1 --- The Concept of Network Coding --- p.15Chapter 2.2.2 --- Related Work --- p.16Chapter 3 --- Adaptive Path and Packet Aggregation System --- p.19Chapter 3.1 --- Overview --- p.19Chapter 3.2 --- The Adaptive Path Aggregation Routing Algorithm --- p.20Chapter 3.2.1 --- Protocol Overview --- p.20Chapter 3.2.2 --- Data Structure --- p.21Chapter 3.2.3 --- The Concept of Link Weight and Path Weight --- p.26Chapter 3.2.4 --- APA Operations --- p.27Chapter 3.3 --- The Packet Aggregation System --- p.39Chapter 3.3.1 --- Overview --- p.39Chapter 3.3.2 --- Packet structure --- p.40Chapter 3.3.3 --- Local Compression --- p.41Chapter 3.3.4 --- Packet Aggregation/Disaggregation --- p.42Chapter 3.4 --- Performance Analysis --- p.44Chapter 3.4.1 --- Integration of the path aggregation routing protocol and the packet aggregation system --- p.46Chapter 3.5 --- Performance Evaluation --- p.48Chapter 3.5.1 --- Testbed Setup --- p.48Chapter 3.5.2 --- Packet aggregation --- p.48Chapter 3.5.3 --- Combined scenario: path and packet aggregation --- p.58Chapter 3.6 --- Summary --- p.65Chapter 4 --- Network Coding System in wireless network --- p.67Chapter 4.1 --- Overview --- p.67Chapter 4.2 --- System Architecture --- p.68Chapter 4.2.1 --- Packet Format --- p.68Chapter 4.2.2 --- Encoding and decoding --- p.69Chapter 4.3 --- Performance Evaluation --- p.71Chapter 4.3.1 --- Experiment Setup --- p.71Chapter 4.3.2 --- Performance Metric --- p.72Chapter 4.3.3 --- Experiment Results --- p.72Chapter 4.4 --- Summary --- p.79Chapter 5 --- Conclusions and Future Directions --- p.8

Energy Efficient Packet Size Optimization for Wireless Ad Hoc Networks

PhDEnergy efficiency is crucial for ad hoc networks because of limited energy stored in the battery. Recharging the nodes frequently is sometimes not possible. Therefore, proper energy utilization is paramount. One possible solution of increasing energy efficiency is to optimize the transmitted packet size. But, we claim that only optimal packet size can not boost the energy efficiency in the noisy channel due to high packet loss rate and overhead. Hence, to reduce the overhead size and packet loss, compression and Forward Error Correction (FEC) code are used as remedy. However, every method has its own cost. For compression and FEC, the costs are computation energy cost and extra processing time. Therefore, to estimate the energy-optimize packet size with FEC or compression, processing energy cost and delay need to be considered for precise estimation. Otherwise, for delay sensitive real time applications (such as: VoIP, multimedia) over ad hoc network, energy efficient optimal packet size can be overestimated. We will investigate without degrading the Quality of Service (QoS) with these two different techniques FEC and compression, how much energy efficiency can be achieved by using the energy efficient optimal packet size for different scenarios such as: single hop, multi-hop, multiple source congested network etc. This thesis also shows the impact of time variable channel, packet fragmentation, packet collision on the optimal packet size and energy efficiency. Our results show that, for larger packets, error correction improves the energy efficiency in multi-hop networks only for delay tolerant applications. Whereas for smaller packets, compression is more energy efficient most of the cases. For real-time application like VoIP the scope of increasing the energy efficiency by optimizing packet after maintaining all the constraints is very limited. However, it is shown that, in many cases, optimal packet size improves energy efficiency significantly and also reduces the overall packet loss