Various Effects of Modulation Schemes on Wi-Fi Network of Urban Scenarios Using QUALNET Simulator

Thousands of enterprises worldwide are cutting the wires to their local area networks (LANs) to enjoy greater productivity from their unwired work force. Many wireless networking systems were established to manipulate urban networks in order to provide internet, data and video etc. connectivity. A significant drawback of traditional Wi-Fi system based on IEEE 802.11b standard is that they are quite vulnerable to sources of interference. Spread spectrum modulation techniques resolve the problem by spreading the information over a broad frequency range. This paper describes and summarizes a study of transmission techniques are explored in order to determine a favorable modulation technique for a particular wireless application for urban scenario. By comparison, it is observed that digital modulation techniques struggles neck to neck for getting low bit error rate (BER), but still with slight change in BER the quality changes a lot.Quality of service (QoS) of any Wi-Fi network is a very important aspect for customer satisfaction. Here QUALNET 5.0 is used to simulate the scenario by changing different modulation schemes (GMSK, QAM64, DQPSK, FSK8) and is analyzed by four parameters (average jitter, average end-to-end delay, throughput, signal Received but with error). The comparative analysis of all the four parameters according to different modulation schemes is done and it will be concluded, which modulation technique gives the best performance and quality of service for URBAN Wi-Fi scenarios.