Delay Performance Evaluation of WIFI Release (IEEE 802.11 a, b, g and n) Using OPNET for Data Types (Voice, email, File Transfer, Video Convergence) Amel Aboud Ali mohamed Alswelih 1 and Dr. Amin Babiker A/Nabi Mustafa 2 1 AL-Neelain University, Faculty of Engineering, MSc of Data Communicatin and Network malamelo@live.com 2 AL-Neelain University, Faculty of Engineering, MSc of Data Communicatin and Network amin31766@hotmail.com tcaatsba IEEE 802.11(WIFI) is the most widely accepted broad band wireless networking technology, providing the high transmission rate among stander wireless networking technology. This paper contains a comparison of some of the WIFI 802.11 standards authored by the Institute of Electrical and Electronics Engineers (IEEE). It explains some of the differences and similarities parameters (delay in email, video conferencing, file transfer, and voice) between the IEEE 802.11(a, b, g, n) by using OPNET 17.5 simulator. Keywords: WIFI, LAN, IEEE, OPNET, ISM, OFDM, QAM, DSSS and MIMO. 1. Introduction Recently, Wi-Fi has become one of the most popular standards for wireless Internet access technology. Using radio frequency connections between a base station (access point) and devices (client) with add-on or built-in 802.11 wireless cards, Wi-Fi gives access to the Internet and remote corporate and personal data without using wires and cables of conventional wired networks in public places, homes, and offices. Wireless LAN (WLAN, also known as Wi-Fi) is a set of low tier terrestrial, network technologies for data communication. The WLAN standard operates on the 2.4 GHz and 5 GHz Industrial, Science and Medical (ISM) frequency bands. It is specified by the IEEE 802.11 standard and it comes in many different variations like IEEE 802.11a/b/g/n. The application of WLAN has been most visible in the consumer market where most portable computers support at least one of the variations. 63 2. Overview of Different Variations of WIFI There are many types of WIFI or generations of 802.11 (a, b, g and n), a brief description about them is gives bellow. (i) IEEE 802.11a: IEEE 802.11a: It operate in 5 GHZ band with maximum data rate of 54Mbps.the major advantage in deploying 802.11a with other IEE 802.11band 802.11g is that, they cannot coexist,as they operate on different frequency band.(3) it less interference because no many device use this frequency. The 5 GHz frequency band uses shorter wavelengths cannot easily to pass through walls. (ii) IEEE 802.11b: A refined standard for the original 802.11 and was successful due to its high data rates of 11 Mb/s - range of 100 m to a maximum of a few hundred meters, operates on 2.4 GHz unlicensed band. 802.11b is the most widely deployed wireless network within the 802.11 wireless families it use DSSS modulation technique that is more reliable than the FHSS. (iii) IEEE 802.11g: IEEE 802.11g stander also operating in 2.4 GHZ band and data rate 54Mbps and it different in modulation technique it use orthogonal frequency division multiplexing (OFDM) (iv) IEEE 802.11n: IEEE 802.11n has become more popular than other because it improve the performance, it
operate in 2.4 and 5GHZ and data rate 450 Mbps on 8x improvement over its predecessors 802.11g and 802.11a which offered 54 Mbps.and it use multi input multi output technique (MIMO).IEEE 802.11n support the binding of two 20Mbps wide WLAN channel into a single 40Mbps wide channel which double throughput between station and client and it use 64 QAM modulation. 3. Quality of service The word Quality is always defined as the degree to which a set of inherent characteristics fulfills a particular requirement. In the field of networking it could be termed as the probability of a packet successfully passing between two points in the network *. It is an ability of a network element (e.g. an application, host or router) to have some level of assurance that its service and traffic requirements would always be satisfied. Every transmission can be negotiated between the server and the client, based on parameters like bandwidth, throughput, delay, jitter and loss. If the parameters provided by the server do not meet the requirements of the client, the connection may be refused. (i) Delay: The time taken by the packets to reach from source to destination is termed as delay. Interactive applications such as video conferencing, web cast and telephony are particularly sensitive to delay. If the delay is not constant for a given stream across the network, the receiver not only experiences delay but also jitter in the delay. 4. Methodology The experiment used OPNET Modeler 17.5 to simulate WiFi standard categories (a, b, g and n) to compare the performance of each one using delay parameter for different data types. As shown in figure (1) below. One access point and 50 work station (client) has been used to simulate the data traffic for 3 minute. Figure (1) Simulation environment 5. Result Simulation results are illustrated by the figures below for delay with different data types namely voice; file transfer, video conference, email. WIFI Performance Parameters Delay Results Fig (2) present the result is the core of voice data type. Blue: 802.11 a 64
Red: 802.11 b Green: 802.11g Green light: 802.11 n Fig (3)present the result is the core of video conferencing. Fig (4) present the result is the core of email. Fig (5) present the result is the core of file transfer. 1-delay performance in the voice: Figure (2) the voice 2-delay performance in video conferencing: Figure (3) the video conferencing 65
3- Delay performance in Email: Figure (4) the email 4-delay performance in file transfer: Fig (5) the file transfer 66
6. Conclusion Simulation results are presented figures 2, 3, 4&5 describe the effect of the different data types on delay. According to the obtained results, it is found that 802.11n&802.11a have scored the minimum delays. The results are very similar. As expected, 802.11n is always associated with minimum delays. On the other hand, the simplicity of 802.11a is the reasons of its limited delay. The delay of 802.11ab is slightly higher there its value in 802.11n &802.11a, while the results of the simulation of 802.11b are the worst among other WiFi releases. References [1] Jan Magne Tjensvold September 18, 2007 [2] Ne Tjensvold September 18, 2007 [3] Dr. Amin Babiker Abdelnabi, Eman OSman Mohamed Wi-Fi 802.11ac and Wi-max 802.16: Comparative study, International Journal Of Advances in Engineering and Management(IJAEM) Volume 1, Issue 5, November - 2014. [4] Dr. Amin Babiker Abdelnabi, Eman OSman Mohamed, review of Wi-Fi 802.11ac and Wi-max 802.16: Comparative study,international Journal Of Advances in Engineering and Management(IJAEM) Volume 1, Issue 5, November 2014. 67