List of Titles

An analytical approach for voice capacity estimation over WiFi network using ITU-T E-model

- Siddique, Md, Kamruzzaman, Joarder, Hossain, Md Jahangir

Authors: Siddique, Md , Kamruzzaman, Joarder , Hossain, Md Jahangir
Date: 2014
Type: Text , Journal article
Relation: IEEE Transactions on Multimedia Vol. 16, no. 2 (2014), p. 360-372
Full Text: false
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Description: To ensure customer satisfaction and greater market acceptance, voice over Wi-Fi networks must ensure voice quality under various network parameters, configurations and traffic conditions, and other practical effects, e.g., channel noise, and capturing effects. An accurate voice capacity estimation model considering these factors can greatly assist network designers. In the current work, we propose an analytical model to estimate voice over Internet Protocol (VoIP) capacity over Wi-Fi networks addressing these issues. We employ widely used ITU-T E-model to assess voice quality and VoIP call capacity is presented in the form of an optimization problem with voice quality requirement as a constraint. In particular, we analyze delay and loss in channel access and queue, and their impacts on voice quality. The proposed capacity model is first developed for a single hop wireless local area network (WLAN) and then extended for multihop scenarios. To model real network scenario closely, we also consider channel noise and capture effect, and analyze the impacts of transmission range, interference range, and WLAN radius. In absence of any existing call capacity model that considers all the above factors concomitantly, our proposed model will be extremely useful to network designers and voice capacity planners.

Increasing voice capacity over IEEE 802.11 WLAN using virtual access points

- Siddique, Md, Kamruzzaman, Joarder

Authors: Siddique, Md , Kamruzzaman, Joarder
Date: 2010
Type: Text , Conference paper
Relation: Global Telecommunications Conference (GLOBECOM 2010), 2010 IEEE p. 1-6
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Description: Voice capacity over IEEE 802.11 networks can be increased with time synchronized medium access, but it is restricted to single hop networks only. We propose a collaborative mechanism that enables client nodes to carry out the time synchronization on ad hoc basis, thereby extends the time synchronized access mechanism over multiple hops, and increases voice capacity considerably. To model real scenario closely, we consider the impact of channel error and employ a Markov chain to determine delay and loss in both medium access and in queue which is then used to derive user perceived voice quality using ITU-T E-model. Our model is then used to determine voice capacity of multichannel, multihop networks. The impact of data rate, interference range, and multiple channels are also analyzed

Performance analysis of m-retry BEB based DCF under unsaturated traffic condition

- Siddique, Md, Kamruzzaman, Joarder

Authors: Siddique, Md , Kamruzzaman, Joarder
Date: 2010
Type: Text , Conference paper
Relation: 2010 IEEE Wireless Communications and Networking Conference (WCNC) p. 1-6
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Description: The IEEE 802.11 standard offers a cheap and promising solution for small scale wireless networks. Due to the self configuring nature, WLANs do not require large scale infrastructure deployment, and are scalable and easily maintainable which incited its popularity in both literature and industry. In real environment, these networks operate mostly under unsaturated condition. We investigate performance of such a network with m-retry limit BEB based DCF. We consider imperfect channel with provision for power capture. Our method employs a Markov model and represents the most common performance measures in terms of network parameters making the model and mathematical analysis useful in network design and planning. We also explore the effects of packet error, network size, initial contention window, and retry limit on overall performance of WLANs.

Performance analysis of PCF based WLANs with imperfect channel and failure retries

- Siddique, Md, Kamruzzaman, Joarder

Authors: Siddique, Md , Kamruzzaman, Joarder
Date: 2010
Type: Text , Conference paper
Relation: 2010 IEEE Global Telecommunications Conference p. 1-6
Full Text: false
Reviewed:
Description: Wi-Fi enabled hand-held devices quickly occupied the consumer market as a result of the remarkable customer acceptance of IEEE 802.11 standard. But the widely used contention based medium access mechanism is unable to meet the increasing traffic demand of today's home users. Especially, delay sensitive multimedia contents suffer heavily from quality degradation under high traffic load. However, the time synchronized medium access mechanism of 802.11 called PCF offers lower delay and loss, and holds true potential in supporting high traffic load. For design and planning of such networks, a thorough performance analysis of PCF based 802.11 WLANs is of profound importance. But existing studies on this lack proper and accurate mathematical modeling considering realistic assumptions, which is investigated in this paper. We develop a Markov chain to analyze the time synchronized PCF based medium access mechanism considering error prone channels, and determine throughput, delay, and packet loss in a WLAN. The impact of traffic load and retry limit is also analyzed. We use our model to analyze performance of PCF mechanism in supporting both data and multimedia traffic.

Voice over multi-channel multi-radio WLANs with power capture and imperfect channel

- Siddique, Md, Kamruzzaman, Joarder

Authors: Siddique, Md , Kamruzzaman, Joarder
Date: 2010
Type: Text , Conference paper
Relation: 2010 IEEE Wireless Communications and Networking Conference p. 1-6
Full Text: false
Reviewed:
Description: VoIP offers cheap voice communication which instigated its quick market growth. IEEE 802.11 WLANs offer cheap wireless coverage which can be used to provide VoIP service in mobile devices. But call capacity of such networks is very low compared to wired networks. To increase voice capacity in WLANs incorporation of power capture, increased data rate, and use of multiple channels are of great importance. Moreover, these networks should be carefully designed considering voice quality requirements to avoid call jitter and call drops. We propose an analytical model to estimate VoIP call capacity for multichannel WLANs with consideration for power capture, imperfect channel, and multiple network interfaces. We employed ITU-T E-model to assess voice quality which is used as the limiting factor to ensure that voice quality does not degrade in such networks. The model will be extremely helpful to network designers in planning single channel or multi-channel WLANs.

VoIP service over multihop 802.11 networks with power capture and channel noise

- Siddique, Md, Kamruzzaman, Joarder

Authors: Siddique, Md , Kamruzzaman, Joarder
Date: 2010
Type: Text , Conference paper
Relation: 2010 IEEE International Conference on Communications p. 1-6
Full Text: false
Reviewed:
Description: The quick market growth and ubiquitous acceptance of VoIP are primarily due to cheap service. VoIP services can be availed in mobile devices at a very low cost by employing IEEE 802.11 to provide last mile coverage. But call capacity is very low in these networks and call jitter occurs if voice quality requirements are not precisely met. We present a VoIP call capacity model for 802.11 networks which considers the most important real world factors like power capture and imperfect channel. Incorporating multiple channels can increase call capacity while multihop network can provide considerably large coverage. Our capacity model incorporates the effects of both multiple channels and multihop networks. We also consider the availability of multiple radio interfaces and conference call scenarios for ubiquitous applications of our model. To ensure voice quality, in addition to contention analysis, we also model the queue considering collision domain at each hop and formulate call capacity by estimating precise impairment budget over multihop.

VoIP capacity over PCF with imperfect channel

- Siddique, Md, Kamruzzaman, Joarder

Authors: Siddique, Md , Kamruzzaman, Joarder
Date: 2009
Type: Text , Conference paper
Relation: IEEE Global Communications Conference (IEEE GLOBECOM2009) p. 1-6
Full Text: false
Reviewed:
Description: Voice, in the form of VoIP, has emerged as a dominating traffic category in the Internet. VoIP traffic suffers from severe voice quality degradation if the end-to-end delay and loss becomes high. PCF medium access mechanism offers delay bound delivery which is a crucial attribute for delay sensitive applications like VoIP. But due to its unavailability in most commercial products, little analysis has been done on PCF for supporting VoIP traffic. Most importantly, standard voice quality assessment methods are not used in the capacity studies. We propose a VoIP capacity model for PCF that uses voice quality as the limiting factor and takes imperfect channel condition into account. The effects of aggregation level, packet error rate and voice quality on VoIP capacity are investigated, and a comparison between voice capacities under PCF and DCF is presented. The proposed model will be extremely useful in designing networks to support quality voice calls.

VoIP call capacity over wireless mesh networks

- Siddique, Md, Kamruzzaman, Joarder

Authors: Siddique, Md , Kamruzzaman, Joarder
Date: 2008
Type: Text , Conference paper
Relation: 2008 IEEE Global Telecommunications Conference p. 1-6
Full Text: false
Reviewed:
Description: In recent years, research on VoIP over wireless mesh network (WMN) has gained particular attention because of its commercial prospect. This paper presents an analytical method to estimate VoIP call capacity in an WMN employing IEEE 802.11 devices. We used Markov chain analysis of IEEE 802.11 for network delay and loss to estimate the capacity while using rating factor, R score, defined by ITU-T, to ensure call quality. A detailed analysis of queueing delay and loss in terms of network parameters is also carried out along with their impacts on voice quality. The capacity model estimates call capacity in a single hop WLAN and is extendable to multi hop scenario and for video communications. The theoretical results are verified by simulation and compared to related previous works.

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