VoIP Codec Adaptation Algorithm in Multirate 802.11 WLANs: Distributed vs. Centralized Performance Comparison

Sfairopoulou, Anna; Macian, C.; Bellalta, Boris

doi:10.1007/978-3-540-73530-4_7

Cited by 6 publications

(5 citation statements)

References 9 publications

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“…In [26] the authors propose an algorithm to dynamically adapt the codec on the basis of the perceived call quality degradation. The latter is evaluated through the computation of E-model parameters.…”

Section: Voip Aware Routing Protocols Distributed Rate and Codec Adamentioning

confidence: 99%

A New Distributed Application and Network Layer Protocol for VoIP in Mobile Ad Hoc Networks

Rango

Fazio

Scarcello

et al. 2014

IEEE Trans. on Mobile Comput.

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In this work a new protocol for Voice over IP (VoIP) transmissions in wireless ad-hoc networks is proposed. Distributed architecture is necessary when dealing with dynamic environments, such as ports or battlefields, where creating infrastructures becomes expensive or impossible. Mobile Ad-hoc NETworks (MANETs) are based on a peer-to-peer approach and each node participates in the organization of the whole network. VoIP over MANETs is a challenging issue due to the intrinsic distributed nature of the existing peer-to-peer paradigm. This paper proposes a new protocol, capable of ensuring a Quality of Service (QoS) level for VoIP calls over a MANET and to manage a higher number of calls in the system. Novel metric and utility functions are proposed to perform the best path selection from source to destination nodes, respecting the QoS parameters for VoIP quality. In particular, an objective metric such as R-factor is considered and a flexibility index is defined, in order to maximize the number of acceptable VoIP calls. Performance evaluation shows that the proposed approach led to better network management in terms of admitted calls and respected QoS constraints.

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Section: Voip Aware Routing Protocols Distributed Rate and Codec Adamentioning

confidence: 99%

A New Distributed Application and Network Layer Protocol for VoIP in Mobile Ad Hoc Networks

Rango

Fazio

Scarcello

et al. 2014

IEEE Trans. on Mobile Comput.

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“…The link and codec adaptation mechanisms [4,5] were one step ahead to construct QoS solution for VoIP over multirate wireless link. These mechanisms are providing resilience and robustness in cellular networks [6].…”

Section: State Of the Artmentioning

confidence: 99%

“…Well-known examples of adaptation mechanism for VoIP over wireless media are PHY/Channel adaptation which allows each mobile node to adapt its transmission rate dynamically to channel condition [7] (Figure 1(a)) and APP/MAC adaptation which adapts the codecs of the active voice flows to the new network conditions (data rate) ( Figure 1(b)). The last one is considered one of the most effective solutions of the multirate problem on VoIP calls [4,5].…”

Section: State Of the Artmentioning

confidence: 99%

“…In this process, the node monitors VoIP activity and codec changes from the upper layers and then, if appropriate, applies adaptation function "1" or goes to the next monitoring process. Output: HELLO interval of (1) Begin (2) if LVA = then (3) read codec parameters: sample size, sample interval (4) if sample size is high then (5) Increase (6) else if sample interval is high then 7decrease (8) end if (9) end if (10) end if (iii) Monitoring Routing Performance-Adaptation Function "Default. " This process occurs when adaptation function "1" or "2" is applied.…”

Section: (I) Monitoring Local Voip Activity-(lva-) Adaptationmentioning

confidence: 99%

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A New QoS Management Scheme for VoIP Application over Wireless Ad Hoc Networks

Brak

Benhaddou

2014

Journal of Computer Networks and Communications

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Nowadays, mobile ad hoc networks (MANETs) have to support new applications including VoIP (voice over IP) that impose stringent QoS (quality of service) constraints and requirements. However, VoIP applications make a very inefficient use of the MANET resources. Our work represents a first step toward improving aspects at the network layer by addressing issues from the standpoint of adaptation, claiming that effective adaptation of routing parameters can enhance VoIP quality. The most important contribution is the adaptive OLSR-VA algorithm which provides an integrated environment where VoIP activity is constantly detected and routing parameters are adapted in order to meet the application requirements. To investigate the performance advantage achieved by such algorithm, a number of realistic simulations (MANET scenarios) are performed under different conditions. The most important observation is that performance is satisfactory in terms of the perceived voice quality.

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“…In particular, the authors in [9] considers two type of voice traffic using different codecs. Also in [21] a dynamic adaptation of the voice codec is proposed to suit the change in transmission rate of the WLAN.…”

Section: Introductionmentioning

confidence: 99%

Dynamic codec with priority for voice over IP in WLAN

Stoeckigt

Branch

2011

Proceedings of the Second Annual ACM Conference on Multimedia Systems

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Research on Voice over IP (VoIP) in infrastructure wireless local area networks (WLANs) has shown that, because of the access mechanism, the access point severely limits the number of voice calls a WLAN can support. To address this problem we propose a new scheme based on the IEEE 802.11e quality of service (QoS) mechanism where a tradeoff between codec quality and priority is exploited to improve the number of calls that can be supported. In particular, we propose certain priority settings at the access point (AP) to encourage users to switch to a lower quality codec during periods of high contention and thus enable them to maintain the call. We develop a detailed analytical model to show the benefit of this scheme. Our analytical results are validated by extensive simulation and show that the voice capacity in the network can be significantly improved. Furthermore, by using the ITU-T E-model to assess the voice quality, we show that users with a lower quality codec can still maintain an acceptable level of quality using the proposed scheme.

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VoIP Codec Adaptation Algorithm in Multirate 802.11 WLANs: Distributed vs. Centralized Performance Comparison

Cited by 6 publications

References 9 publications

A New Distributed Application and Network Layer Protocol for VoIP in Mobile Ad Hoc Networks

A New Distributed Application and Network Layer Protocol for VoIP in Mobile Ad Hoc Networks

A New QoS Management Scheme for VoIP Application over Wireless Ad Hoc Networks

Dynamic codec with priority for voice over IP in WLAN

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