Evaluating the Performance of VoIP Over Different Wireless Environment

WiFi and WiMAX are the most technologies for broadband wireless access are used nowadays. The excessive demand for providing mobile users with broadband wireless access has attracted tremendous investment from the telecommunications industry in the development and deployment of WiMAX and WiFi networks. Voice over IP (VoIP) over these technologies will be one of the killer applications for rapid deployment of WiMAX and WiFi networks. The legal desire for bundling voice and data will increase the portion of voice traffic in these networks. Therefore, VoIP, as the current technology for making voice calls through packet switch networks, will be a key application in WiMAX and WiFi networks. The increase of Voice over IP (VoIP) applications such as Skype, Google Talk, and MSN Messenger along with emerging deployment of WiMAX networks is making VoIP over WiMAX an attractive market and a driving force for both carriers and equipment suppliers in capturing and spurring the next wave of telecommunications innovation, though challenges remain. However, the enhancement on the hardware and application sides only seems inadequate. The chosen of proper network environment is also crucial in order to deliver the voice communication and multimedia session over the Internet. Optimization of the VoIP call capacity over WiMAX and WiFi networks is one such crucial challenge and remains an open research issue. Hence, in this project, we present the performance evaluation of VoIP in two wireless network protocols, WiMAX and WiFi as a baseline to evaluate the VoIP performance

Investigating the QoS of Voice over IP using WiMAX Access Networks in a Campus Network

VoIP is a very rapid evolving communication technology which supports transportation of voice data via IP based networks. In parallel, IEEE 802.16e standard based WiMAX is a new emerging access technology and the first generation of 4G broadband access wireless technology with an enhanced in-built quality of service (QoS) provision with many benefits including cost reduction, high quality as well as other value added network service solutions especially for communications Service Providers with emphasis on real time services. WiMAX promises manifold benefits in terms of optimal network performance across a long distance in contrast to other wireless technologies such as Wi-Fi and 3G cellular technologies. Hence, this research attempts to identify some of the network performance parameters that Service Providers will focus on to develop a VoIP over WiMAX communication tool that will serve as a voice communication broadband replacement technology to old circuit-switch voice communication. This study adopted a simulation-based network performance analysis to investigate the effects of the application of different voice encoder schemes on QoS of VoIP system deployed with IEEE 802.16e standard WiMAX network. Through different network simulation experiments using realistic network scenarios in OPNET environment, this research provided an in-depth network performance comparative analysis of VoIP over WiMAX using performance parameters which indicate QoS such as voice jitter, voice packet ETE delay, packet-sent-packet-received, WiMAX network delay, voice packet delay variation and throughput. The obtained simulation experiment results indicated that choice of suitable codec scheme can affect the QoS of VoIP traffic over WiMAX network. The results also indicated that the choice of suitable voice encoder scheme with a small number of voice frame-size per packet have a significant impact over VoIP traffic performance when deployed with WiMAX access technology. Keywords: WiMAX, QoS, End-to-End delay, Jitter, IEEE 802.16e, PSTN, OPNET, Simulation, Wi-Fi, Code

Suporte de mobilidade em redes WIMAX

O desenvolvimento crescente da Internet, com novos serviços e aplicações que requerem elevadas exigências a nível de qualidade de serviço, como por exemplo, o VoIP e IPTV, a crescente necessidade de um utilizador estar sempre contactável em qualquer sítio e a qualquer momento, torna necessária a integração actual da Internet com as redes móveis da próxima geração. A tecnologia IEEE 802.16 surge como uma tecnologia de banda larga sem fios que pode ter um papel fundamental num ambiente de próxima geração. Devido aos seus baixos custos de instalação e à possibilidade de chegar facilmente a zonas rurais ou a zonas de difícil acesso, torna-se um sério candidato para suprir as necessidades dos utilizadores. A necessidade de mobilidade pelo utilizador, para aceder a diversos serviços em diferentes sítios ou ser identificado remotamente para a posterior recepção de informação também é um desejo futuro. O protocolo IEEE 802.21 surge como um meio que providencia a optimização de handover entre diferentes tecnologias de acesso, quer sejam elas WiFi, WiMAX, 3GGP ou 3GPP2, no sentido de proporcionar ao utilizador a utilização de diferentes serviços de uma forma transparente à tecnologia de acesso, quando em situações de mobilidade. Esta dissertação apresenta a arquitectura desenvolvida para proporcionar a correcta avaliação da atribuição de QoS e mobilidade transparente, num ambiente real de próxima geração. Serão também efectuados testes com o equipamento WiMAX disponível, no sentido de mostrar o seu correcto comportamento na atribuição de QoS fim-a-fim em cenários ponto-a-ponto e ponto-a-multiponto com serviços com características de tempo real. A integração do software da primeira fase do projecto WEIRD e o seu correcto comportamento em ambientes de atribuição de QoS também vai ser estudado. A implementação dos diferentes módulos, em especial a implementação da unidade central da arquitectura de IEEE 802.21 (MIHF), vai ser descrita, no sentido de avaliar o desempenho do WiMAX e do protocolo IEEE 802.21 numa rede real no âmbito da segunda fase do projecto WEIRD. Os resultados obtidos demonstram que a arquitectura desenvolvida consegue fornecer QoS fim-a-fim com suporte de mobilidade entre redes heterogéneas. ABSTRACT: The growing development of the Internet, with new services and applications that require a high level of quality of service, such as, VoIP and IPTV, the increasing need for a user to be always reachable anywhere and at anytime, motivates the integration of current Internet with the next generation of mobile networks. The IEEE 802.16 technology emerges as a technology for broadband wireless access that may have a key role in a next generation environment. Due to its low costs of installation and its ability to easily reach rural areas or areas with difficult access, it becomes a serious candidate to supply the needs of users. The mobility’s necessity by the user, to access to several services in different locations or be identified remotely for subsequent receipt of information, is also a future desire. The IEEE 802.21 protocol provides the optimization of handover between heterogeneous networks, such as WiFi, WiMAX, 3GGP or 3GPP2, to offer the user different services in a transparent manner to his access technology, when in situations of mobility. This Thesis presents the architecture developed to provide the correct integration of QoS and seamless mobility, in a real next generation environment. It will also present tests carries out with the available WiMAX equipment, to show its correct behaviour in the allocation of end-to-end QoS in point-to-point and point-to-multipoint scenarios with real-time services. The integration of software from the first phase of the WEIRD project and its correct behaviour in environments of QoS allocation will also be studied. The implementation of the various modules, in particular the implementation of the central unit of IEEE 802.21 architecture (MIHF), will be described, to evaluate the performance of WiMAX and IEEE 802.21 protocol in a real network provided by the second phase of the WEIRD project. The obtained results show that the developed architecture is able to provide end-toend QoS with seamless mobility support over heterogeneous networks

Cognitive self-management for voip quality of service in wireless networks: design and performance evaluation

Στα πλαίσια της παρούσας διπλωματικής εργασίας, σχεδιάστηκε και υλοποιήθηκε ένα αλγοριθμικό πλαίσιο για την εγγύηση ποιότητας υπηρεσίας (QoS) φωνής (VoIP) στο ασύρματο περιβάλλον WiMAX. Πιο συγκεκριμένα, αναπτύχθηκε ένας μηχανισμός λήψης απόφασης για την επιλογή της καταλληλότερης ενέργειας προσαρμογής κάτω από συνθήκες φόρτου. Οι πιθανές ενέργειες προσαρμογής είναι η αλλαγή της προτεραιότητας των πακέτων φωνής στον σταθμό βάσης και η αλλαγή κωδικοποίησης της φωνητικής υπηρεσίας. Για τον υπολογισμό της έντασης κάθε ενέργειας προσαρμογής αναπτύχθηκαν μια ευριστική μέθοδος και μια μέθοδος βασισμένη στο ιστορικό παλαιοτέρων ενεργειών. Επιπρόσθετα, υλοποιήθηκε ένας μηχανισμός ανατροφοδότησης του συστήματος προκειμένου να γίνει αυτο-ρύθμιση των κατωφλίων απόφασης με χρήση μηχανικής μάθησης. Η απόδοση του υλοποιημένου πλαισίου αξιολογήθηκε στις εγκαταστάσεις του έργου Panlab το οποίο διέθεσε τον κατάλληλο εξοπλισμό για την ανάπτυξη ενός πειραματικού δικτύου WiMAX. Τα αποτελέσματα αποδεικνύουν ότι οι παράγοντες που επηρεάζουν την ποιότητα υπηρεσίας, όπως απώλεια πακέτων (packet loss), χρονοκαθυστέρηση (delay), διακύμανση της χρονοκαθυστέρησης (jitter) και ο συνδυαστικός παράγοντας R-score βελτιώνονται σημαντικά χρησιμοποιώντας το προτεινόμενο αλγοριθμικό πλαίσιο. Τέλος, θίγονται και αναλύονται ζητήματα εφαρμογής και δυναμικής λειτουργίας του συστήματος.Modern services pose strict requirements on fulfilling their quality indicators, with network operators struggling to increase the provided resources. Sophisticated performance management is needed for autonomic and efficient configuration of available network resources. The incorporation of cognitive capabilities in network management and its cooperation with the service stratum, provide the means for the development of novel performance management solutions. In this work, we propose an algorithmic framework for VoIP QoS assurance in a wireless broadband network environment. We introduce a decision making scheme for the selection of the most appropriate adaptation under congestion conditions, choosing between VoIP flows’ priority change at the wireless base station and the change of VoIP flows’ codec. A History-based method calculates the intensity of each adaptation, while a heuristic approach is used for un-classified situations. The proposed learning scheme, based on the feedback of previous actions, self-tunes the decision making tasks. We have implemented and empirically evaluated the solution in FIRE Panlab experimental facility using a WiMAX network. The results show that VoIP QoS features (packet loss, delay, jitter, R-score) are significantly improved via the proposed solution, satisfying adaptive evolution requirements. Applicability issues and the dynamic operation of the system are also analysed