A Survey on Enhancing the QoS through voice Quality for Voice over Wireless LANs (VoWLAN)

Voice over Internet Protocol (VoIP) is one of the important technologies that allow voice transmission over the IP network. Various voice codec are available for VoIP as this is a rapidly changing technology. It can be an effective renewal for the traditional telephone systems (PSTN) because of extreme utilization of its sources as well as to provide very low cost. Apart from, Wireless Local Area Network (WLAN) has become apparent as a durable networking technology. Hence, the combination of these two popular technologies is growing so fast all over the world. Voice over WLAN will be a tool to provide low-cost and reliable voice services on wireless media. However just like other wireless applications, VoWLAN has also faced few challenges that need to be considered. Quality of Service (QoS) is one of the primary requirements in different kind of wireless applications. In this survey some of the important QoS requirement (latency, delay, jitter etc) have been analyzed, and it also has the introspection of the E- model and MOS (Mean Opinion Score) value for voice quality while using of different ITU-T codec. Therefore it makes Voice over WLAN a challenging research topic. In this study we will address all VoWLAN issues. DOI: 10.17762/ijritcc2321-8169.150516

IMPROVING QoS OF VoWLAN VIA CROSS-LAYER BASED ADAPTIVE APPROACH

Voice over Internet Protocol (VoIP) is a technology that allows the transmission of voice packets over Internet Protocol (IP). Recently, the integration of VoIP and Wireless Local Area Network (WLAN), and known as Voice over WLAN (VoWLAN), has become popular driven by the mobility requirements ofusers, as well as by factor of its tangible cost effectiveness. However, WLAN network architecture was primarily designed to support the transmission of data, and not for voice traffic, which makes it lack ofproviding the stringent Quality ofService (QoS) for VoIP applications. On the other hand, WLAN operates based on IEEE 802.11 standards that support Link Adaptive (LA) technique. However, LA leads to having a network with multi-rate transmissions that causes network bandwidth variation, which hence degrades the voice quality. Therefore, it is important to develop an algorithm that would be able to overcome the negative effect of the multi-rate issue on VoIP quality. Hence, the main goal ofthis research work is to develop an agent that utilizes IP protocols by applying a Cross-Layering approach to eliminate the above-mentioned negative effect. This could be expected from the interaction between Medium Access Control (MAC) layer and Application layer, where the proposed agent adapts the voice packet size at the Application layer according to the change of MAC transmission data rate to avoid network congestion from happening. The agent also monitors the quality of conversations from the periodically generated Real Time Control Protocol (RTCP) reports. If voice quality degradation is detected, then the agent performs further rate adaptation to improve the quality. The agent performance has been evaluated by carrying out an extensive series ofsimulation using OPNET Modeler. The obtained results of different performance parameters are presented, comparing the performance ofVoWLAN that used the proposed agent to that ofthe standard network without agent. The results ofall measured quality parameters hav

Performance and Analysis of Transfer Control Protocol Over Voice Over Wireless Local Area Network

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree Master of Science by Rajendra Patil in August of 2008

VoIP over WLAN: What about the Presence of Radio Interference?

In this chapter, the performance of VoIP over WLAN is analyzed under the effect of physical layer interference, in the presence and absence of cross-traffic. The goal is twofold: first to underline the importance of radio interference in the behavior of a WLAN when supporting VoIP applications; second to outline solutions to avoid interference and thus optimizing a VoIP call over aWLAN. To this aim, an experimental approach based on cross-layermeasurements is adopted, describing and commenting meaningful results obtained from a number of experiments conducted by the authors on a testbed operating in a semi-anechoic chamber and emulating two typical real life scenarios

ANVIA ENTERPRISE WIRELESS LOCAL AREA NETWORK MARKET ANALYZES AND BUSINESS MODEL ENHANCEMENTS.

For almost 15 years, since it has been released, Wi-Fi has been one of the dominant technologies in telecommunication world. However, because of its weaknesses related to security, interference and weak quality of service it has not been accepted as a viable business. Furthermore, it also operates in unlicensed spectrum bands which magnify these issues. On the other hand, technological innovations through new improvements in the world of Wi-Fi have made it one of the most popular indoor communication solutions for enterprises as well as in outdoor common meeting points. Therefore, it has become imperative to study this subject due to its popularity and several issues associated with this technology to create a viable business model for Anvia Oyj. In an attempt to contribute towards this field, present thesis provides a comprehensive theoretical framework that addresses WLAN technology from different aspects including Wi-Fi roaming as well as the description of business model segments. In order to strengthen enterprise WLAN business models, a comprehensive data was collected through different resources. First, an internal interview in Anvia Oyj based on its current enterprise WLAN business model was conducted. Secondly, two surveys were conducted in different enterprise WLAN customer segments; 32 interviews with small office home office (SOHO) enterprises and 10 interviews with SMEs/LEs and municipalities. Thirdly, a global enterprise WLAN market analysis was conducted through Internet resources. Based on these, analyzes, recommendations and business model enhancements are suggested in this thesis. The findings of this research will help Anvia Oyj to achieve better performance in enterprise WLAN business segment.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

IMPROVING QoS OF VoWLAN VIA CROSS-LAYER BASED ADAPTIVE APPROACH

Voice over Internet Protocol (VoIP) is a technology that allows the transmission of voice packets over Internet Protocol (IP). Recently, the integration of VoIP and Wireless Local Area Network (WLAN), and known as Voice over WLAN (VoWLAN), has become popular driven by the mobility requirements ofusers, as well as by factor of its tangible cost effectiveness. However, WLAN network architecture was primarily designed to support the transmission of data, and not for voice traffic, which makes it lack ofproviding the stringent Quality ofService (QoS) for VoIP applications. On the other hand, WLAN operates based on IEEE 802.11 standards that support Link Adaptive (LA) technique. However, LA leads to having a network with multi-rate transmissions that causes network bandwidth variation, which hence degrades the voice quality. Therefore, it is important to develop an algorithm that would be able to overcome the negative effect of the multi-rate issue on VoIP quality. Hence, the main goal ofthis research work is to develop an agent that utilizes IP protocols by applying a Cross-Layering approach to eliminate the above-mentioned negative effect. This could be expected from the interaction between Medium Access Control (MAC) layer and Application layer, where the proposed agent adapts the voice packet size at the Application layer according to the change of MAC transmission data rate to avoid network congestion from happening. The agent also monitors the quality of conversations from the periodically generated Real Time Control Protocol (RTCP) reports. If voice quality degradation is detected, then the agent performs further rate adaptation to improve the quality. The agent performance has been evaluated by carrying out an extensive series ofsimulation using OPNET Modeler. The obtained results of different performance parameters are presented, comparing the performance ofVoWLAN that used the proposed agent to that ofthe standard network without agent. The results ofall measured quality parameters hav

VOIP WITH ADAPTIVE RATE IN MULTI- TRANSMISSION RATE WIRELESS LANS

“Voice over Internet Protocol (VoIP)” is a popular communication technology that plays a vital role in term of cost reduction and flexibility. However, like any emerging technology, there are still some issues with VoIP, namely providing good Quality of Service (QoS), capacity consideration and providing security. This study focuses on the QoS issue of VoIP, specifically in “Wireless Local Area Networks (WLAN)”. IEEE 802.11 is the most popular standard of wireless LANs and it offers different transmission rates for wireless channels. Different transmission rates are associated with varying available bandwidth that shall influence the transmission of VoIP traffic

VOIP WITH ADAPTIVE RATE IN MULTI- TRANSMISSION RATE WIRELESS LANS

“Voice over Internet Protocol (VoIP)” is a popular communication technology that plays a vital role in term of cost reduction and flexibility. However, like any emerging technology, there are still some issues with VoIP, namely providing good Quality of Service (QoS), capacity consideration and providing security. This study focuses on the QoS issue of VoIP, specifically in “Wireless Local Area Networks (WLAN)”. IEEE 802.11 is the most popular standard of wireless LANs and it offers different transmission rates for wireless channels. Different transmission rates are associated with varying available bandwidth that shall influence the transmission of VoIP traffic

Channel Sampling Strategies for Monitoring Wireless Networks

Monitoring the activity on an IEEE 802.11 network is useful for many applications, such as network management, optimizing deployment, or detecting network attacks. Deploying wireless sniffers to monitor every access point in an enterprise network, however, may be expensive or impractical. Moreover, some applications may require the deployment of multiple sniffers to monitor the numerous channels in an 802.11 network. In this paper, we explore sampling strategies for monitoring multiple channels in 802.11b/g networks. We describe a simple sampling strategy, where each channel is observed for an equal, predetermined length of time, and consider applications where such a strategy might be appropriate. We then introduce a sampling strategy that weights the time spent on each channel according to the number of frames observed on that channel, and compare the two strategies under experimental conditions