Quality of Service over Wireless Network (on VoIP)Abstract—As in the innovation in the 4.0 era, wireless networks as a key solution rapidly growth in both flexible and economical to provide broadband and mobile wireless connectivity. A Wireless Network is a transmission network made up of the mixture of wireless nodes accomplished in a mesh topology. Quality of Service (QoS) is particularly important in networking, but for Voice over IP (VoIP), it faces many technique challenges. This paper will present and discuss the challenges and solutions in providing QoS for VoIP in the wireless data network on VoIP.Index Terms—Keywords should be taken from the taxonomy Quality-Of-Service, Wireless Network, Voice over IP.—————————— ? ——————————INTRODUCTIONA wireless network is a computer network that uses wireless data connections between network nodes. Wireless networking is a method by which homes, telecommunications networks, and business installations avoid the costly process of introducing cables into a building, or as a connection between various equipment locations. Wireless networks are becoming more and more ubiquitous in recent years, ranging from mobile analog and digital cellular telephony up to satellite broadcasting. VoIP is a new Internet application and has been receiving an ever increasing attention. Prime advantages of the VoIP are lower cost for the customers and higher profits for the providers, as compared to traditional telephone networks. Quality of Service (QoS) is an important part of the networking world. It prioritizes certain activities on our network over others and dictates the quality of the services provided by the Internet Service Provider(ISP). In this report, I will be discussing the QoS in the wireless network for VoIP.2. RELATED WORK OR LITERATURE REVIEW 2.1. Review Stage 1In the early 2000, tech savvy countries like Korea showed rapid growth in Voice Over Internet Protocol(VOIP). Domestic carriers, formally reluctant to invest in VOIP, have now started to invest into VOIP in recognition to the popular current telecommunication industry as well as the competition in today’s market. Internet telephony is becoming the norm and it offers powerful technology that enables many things beyond straight voice calling. For example, VOIP services support a variety of option such as pc-to-pc, pc-to-smartphone, and smartphone-to-smartphone. This enables inbounds and certain calls where the calls can suffer from noticeable quality issues. Compared to the regular landline and mobile phone plans who charge us higher rates mostly by making international calls, VOIP has changed the way in which we communicate with people with bypassing of the regular telephone companies thus reducing in the cost of 50% – 95%. It has considerable influences on VOIP call demands. Due to the government regulation, some countries don’t support the VOIP services. Nowadays, many service providers require proper Quality of Service(QoS) transmission of audio and sometimes telecommunication over packet-switching. Packet-switching is used as a primary data communication worldwide. The very first thing you need to guarantee in order to guarantee quality for VoIP is adequate bandwidth. Problems that can impair the quality can include audio compression and decompression algorithm, network-traffic delays, loss, noise and many other types of distortion. In fig-1 it shows us the most parameters that have affected the QoS in the recent years. Figure 1. Distribution of QoS parameters in the literature over the recent yearshttp://ieeexplore.ieee.org/document/7820167/?part=undefined%7Cfig2#fig2 Delay transmission in the network seems to be the main problem in contrast to fig-1 which can be avoided by minimizing the delay and maximizing the packet delivery ratio to aid in the better quality of service. At the decompression level in a wireless network traffic, the packets must arrive in equal spacing. When there is network delays packets are received in a distorted manner or different time intervals, therefore, It makes use of the jitter buffer to allow calculated delays Instead of in receiving delays. 1 Speaking of measuring the network, the parameter as packet loss were obtained as results of simulations performed. Figure 2. Voice quality as a function of packet loss rate. The chart fig-2 shows that as the packet loss rate increases the voice quality significantly degrade. The packet loss occurs when more people are using the internet and routers as it gets congested more often. (It has been shown that an end-to-end delay of over 150 milliseconds (ms) is intolerable to VoIP users, and the delay between packets must be lower than 20 ms for uninterrupted and smooth hearing.2 An IP packet can carry 40-80 ms of speech information. While some are lost in a continuous speech, the human brain can reconstruct few lost phonemes in speech, however, too much packet loss can make it impossible to understand.2 M. Hassan, “Internet Telephony: Services, Technical Challenges, and Products”, IEEE Communication Magazine, Apr. 2000. Fig 3. Skype annual growth from 2005-2013According to T.Gara, TeleGeography research shows that in 2013, Skype carried an estimated 214 billion minutes of international ‘on-net’ calls, which grew up 36% compares to 2012. Surprisingly, Skype’s traffic was about 40% the size of the entire international telecom market. As shown in fig 3, the international calling minutes has constantly increased from 5 billion minutes call to 54 billion minutes call in 9 years from 2005 to 2013 and has no signs of stopping. Skype growth is leading in the international calling industry, its growth in 2013 of 54 billion minutes is about 50% higher than the growth of the rest industry in the market. TeleGeography predicted the phone switched telephone network will be using and not disappear for whilst. Numbers show that at the end of 2013, there are 1.2 billion users using Facebook every month whilst PSTN only connected to about 8 million fixed and mobile subscribers worldwide. 3http://tcnews.webs.com/tcnews032014/tcnews03a22y2014.pdf 2.2 Review Stage IIOne of the most important things that must be configured in concert with available VoIP solutions is Quality of Service (QoS). Without QoS options properly configured, the quality of voice (and video) could, and probably will be, sacrificed along with the overall demands of general traffic. Studies on ‘listen-ability’ on voice over IP experiments show that the packet loss burstiness a significant impact on QoS of voice due to rerouting or sudden network spikes. “Packet dispersion in IP networks is a mechanism in which application packets are dispersed between parallel paths leading from the source to the destination, based on a predefined dispersion strategy.” 4 Packet dispersion divide a flow into several parts based on the network conditions then balance network traffic loads. It can be implemented by the source application or by nodes in the network. Then from several parts itself transmitted through different paths. Studies results indicate that the packet dispersion technique reduces consecutive packet losses and improves voice qualityIII. PROPOSED SOLUTION/ MODEL/ APPROACHOur Proposed solution is to provide Quality of Service that will ensure the delay and sensitive voice traffic will be receiving the proper priotrization and queuing required. The problems that we took into account when deciding our solution were: voice traffic cannot be delayed because we don’t want words to be delayed and randomly said in a middle of conversation.lost packets are dropped so the conversation will not have intelligence.Transmitting for only 20msec at a time, therefore when we lose voice packet we only lose acceptable 20msec. Lost packets are not re-requestedDelayed packets are droppedShould be able to have real-time voice communication Delay limit maximum of 300 mSec because it goes against the rules of talking as too much delay can result in awkward pauses or overlapping communication between people. This is especially worse in long distance calls.