The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper focuses on proposing approaches for the improvement of Voice over Internet Protocol (VoIP) service quality in Wireless Mesh Network (WMN). While WMNs have self-healing, self-forming and dynamic topology features, they still pose challenges for the implementation of multimedia applications, such as voice, in various scenarios. The research has been conducted using a network simulator and...
Voice over Internet Protocol (VoIP) has become a recent topic of research in both the Internet and the Telecommunication industry. The terrific increase in popularity of VoIP services is a result of huge growth in broadband usage. Both in wired as well as in wireless communication, VoIP is replacing the traditional telephony techniques. To ensure a good quality speech through VoIP, certain Quality...
This paper investigates and compares the performance of the popular VoIP codecs G.711, G.723.1 and G.729A over an IP network based on SIP architecture, using RTP as a transport protocol. This is based on different simulations in order to evaluate the performance of each codec and to find the optimal codec. For this objective this paper analyzes Quality of service (QoS) parameters, principally delay,...
Enhanced Distributed Channel Access (EDCA) is a mandatory part of the IEEE 802.11e standard which provides Medium Access Control (MAC) layer solution for Quality of Service (QoS) provisioning in Wireless Local Area Networks (WLANs). It is a contention based protocol which prioritizes channel access to QoS traffic using four Access Categories (ACs). In this paper, we introduce the performance evaluation...
The next generation technology of Voice over Internet Protocol (VoIP) allows voice to be delivered over the Internet Protocol based networks. The integration of VoIP and Wireless Local Area Network (WLAN) has become popular. However, WLAN architecture was primarily designed to carry data and not for real-time applications, such as VoIP. Hence, there is a need to enhance the quality of VoIP transmission...
This paper proposes a solution for throughput and stringent delay problems of VoIP in Ad-Hoc mode of IEEE 802.11 WLAN standards. This paper analyses the behaviour different codecs and schemes of WLAN running on VoIP traffic and draws a conclusion on the performance of network based on the criteria of different QOS parameters. Later the suitability of different routing protocols like AODV, DSR, OLSR...
Voice over Internet Protocol (VoIP) is a technology that transports voice data packets across packet switched networks using the Internet Protocol (IP). The key research is to develop a new method for QoS determination and dynamic control of the network that is applicable to VoIP industry. The paper investigates the effects of packet loss, delay and jitter on speech quality for VoIP. It extends the...
Next Generation Network (NGN) is a packet based network which can support the expansion of broadband and introduction of triple play (Voice +Data +Video) over fixed and mobile line. Before deployment of NGN, the capacity and Quality of Service (QoS) over NGN must be ensured. In this paper, the technologies proposed by Huawei have been applied to ensure the capacity and QoS over NGN. Then the optimized...
Modern Line of Sight (LOS) radio technologies including software defined radios are the fundamental building blocks of the future game-changing High Speed and High Capacity Internet Protocol based Airborne Networks (HSCAN) for the U.S. military. The Air Force currently has multiple ongoing initiatives to develop this future HSCAN. The chief capability amongst many others that the Air Force envisions...
Existing uplink scheduling schemes at subscriber station (SS) in WiMAX suffer from problems like waste of resources and greater access delay for VoIP services. We propose an efficient uplink scheduling scheme to solve above mentioned problems. The SS uses two reserved bits of generic MAC header of IEEE 802.16d to record the voice status of current time unit and informs the base station (BS) without...
End-user acceptance criteria of live-stream based, interactive applications are different from traditional B2B or B2C applications. For example, if users sense disruptions in audio or video stream quality, they may quickly form a negative opinion. The Quality of Experience (QoE) in such live-stream applications is, thus, based on perception, and is open to subjective interpretations. QoE can be affected...
Voice over IP (VoIP) is an emerging service and has gained popularity in recent years. The most challenging task for a service provider is to provide and monitor better voice quality. The nature of quality of service (QoS) in VoIP networks is very variable and hence it is important to be able to measure the QoS offered by the system in real time with a low computational cost. In this paper, we discuss...
Voice over Internet Protocol (VoIP) services are susceptible to Internet Protocol (IP) network burstiness causing packets drop and momentary gap in the call. The main objective of this paper is to study the effect of various voice codec schemes on the VoIP Quality of Service (QoS). Popular voice codecs such as G.711, G.729A Conjugate-Structure Algebraic-Code-Excited Linear-Prediction (CS-ACELP), G...
Voice over Internet Protocol is a growing technology that enables voice communication through the Internet. The transmission of audio data over packet switched networks faces lot of difficulties by a variety of network impairments. Such networks are not designed to support real time voice communication because of their variable characteristics. The conversational quality of a VoIP communication is...
Wireless ad hoc networks are a collection of mobile nodes spreading over a defined geographical area, enabling realtime collaborative applications such as push-to-talk and VoIP. Unfortunately, wireless ad hoc networks suffer from limited bandwidth and QoS constraints. A proposed eXplicit MultiCAST (XCAST) based routing protocol (P-XCAST) is presented in this paper to support team-based communications...
IEEE 802.16e, a broadband wireless access technology that provides high speed Internet access and multimedia services has seen very significant growth in recent times. With the due rapid deployment of WiMAX, there would be a growing demand for efficient support of voice applications. The performance of voice over IP services depends on a proper scheduling algorithm combined with a proper voice encoder...
This paper evaluates the QoS performance of transporting voice using WiMAX MBS (multicast/broadcast service). Our results demonstrate that the proposed MBS architecture can address several design issues arising from the mobility of the relay stations and the mobile stations. The service architecture is feasible for voice transport in the WiMAX multi-hop network.
With the rapid development of the Internet, new technologies and applications are emerging. One of the important applications is voice over IP. Satellites are playing an important role to provide VoIP services with their global coverage and on-board processing ability over IP networks. Satellite network environment, generally characterized by large delay and erroneous link, is considered to be unfriendly...
Obtaining VoIP security through the IPsec protocol increases packet size, thus substantially increasing the network overhead. One way of mitigating such a problem consists of multiplexing calls so that the transmission of redundant data is reduced. The performance of such technique is directly linked to the number of concurrent calls; however, in more constrained scenarios, the existence of several...
This paper presents a method for adaptive rate control in a video conferencing solution over a variable bandwidth channel. The bandwidth is estimated using the round-trip delay of probe packets. Based on the estimated bandwidth, the video rate adaptation is done in two folds; one in the H.264 video encoder based on adaptive basic unit selection and the other by generation of fragments for encoding...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.