The migration to 4G networks will bring a new level of expectation to wireless communications. As after digital wireless revolution made mobile phones available for everyone, the higher speeds and packet delivery of 4G networks will make high quality multimedia available everywhere. The key to achieving this higher level of service delivery is a new air interface, OFDM, which is in turn enabled by the high level of performance. OFDM provides a robust signal that requires relatively little power yet uses bandwidth very efficiently. Carriers will benefit from greater flexibility by using OFDM, since in the same spectrum they will be able to offer more channels, including higher-bandwidth channels, with more types of services. Currently these systems are still being defined and prototyped. Achieving higher data rates requires OFDM systems to make more efficient use of the bandwidth than CDMA systems. One method of achieving this higher efficiency is through the use of higher order modulation. In this paper we have compared two digital modulation techniques QPSK and DQPSK used for digital transmission of data. Our main objective to develop this configuration is to compare the performance of each modulation techniques. Comparison is done by Bit Error Rate analysis of both modulation techniques. We have developed existing configurations and improved them with high quality senders and receivers using MATLAB technology. In this paper we have also considered how OFDM can improve the real time video streaming over the wireless network. We have considered the problem of multiuser video streaming over OFDM. OFDM is a multi carrier modulation. The growing interest in Multi-Carrier Transmission by researchers and product developers motivated us to propose this topic for a special issue of Wireless Video transmission and Communications.

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QPSK- Quadrature Phase Shift Keying DQPSK- Differential Quadrature Phase Shift Keying OFDM-Orthogonal Frequency Division Multiplexing QoS-Quality of service