Study Of Vary-rate MQAM Modulation Technology And Its Application In Mobile Communication

The improvement in people's living standard, people require better methods to acquire information, the third generation of mobile communication system was raised accordingly. Because the third generation of mobile communication will provide integrated multimedia service at high rate with high quality, it certainly solves the problem of how to transmit the high rate data in the limited frequency resource, that is how to improve the utilization ratio of the frequency resource. MQAM is a modulation technology that has a higher utilization ratio of frequency band. If it is applied in the mobile communication system, the problem of tension of the frequency resource can be solved. However, the anti-interference is not good for the MQAIVI, its application will be limited, so it is important and significant to study a feasible scheme of MQAM. This subject is to design a simulation scheme of vary-rate MQAM transmission system, and to research its application in the wireless mobile rayleigh channel. In this paper, the author begins his research into some characteristics of electromagnetic wave, and then analyzes the effect of the digital signal transmission on the wireless mobile fading channel, and created a simulator for rayleigh fading channel. Besides, the error-code characteristics of several modulation technology, such as the rectangle QAM, the circle QAM and the MPSK, are analyzed and compared in details, and the circle QAM is selected as an optimal scheme on the wireless mobile fading channel. Meanwhile, the author finished a scheme design for the adapted vary-rate MQAM transmission simulation system. In order to implement the quasi-real time simulation, the modularization and the multi-thread construction are used in the software design. At the end, the simulation results could be indicated directly, vividly and dynamically.