World Journal of Engineering Research and Technology

Srishti Nema* and Dheeraj Nagar

ABSTRACT

Now-a-days the requirements of wireless communication are to have high voice quality, high data rates, multimedia features, lightweight communication devices etc. But the wireless communication channel suffers from much impairment. One of them is fading which is due to the effect of multiple propagation paths, and the rapid movement of mobile communication devices. This paper analyses the various digital modulation techniques used in the present Wireless communications which has become the need of today. Here we see the various digital bandpass modulation schemes like the phase shift keying, frequency shift keying, amplitude shift keying and the M- ary signalling used most widely in wireless communications these days. Digital modulation contributes to the growth of mobile communications by increasing the quality, speed and capacity of the wireless network. In the communication, the idea of modulation is a primary factor for the reason that without a scheme of appropriate modulation, it would be not possible to attain a planned flow. The offered bandwidth, allowable power and the level of inherent noise of the system are the constraints which must be taken into account in the development of communication systems. Because of the error free capacity in the digital modulation, it is chosen over the techniques of analogue modulation. The WiMax uses combinations of distinct modulation schemes such as BPSK, QPSK, 4-QAM and 16-QAM and it is a capable technology which provides video, data and high speed voice services. In this literature the review of documentation on the various digital modulation techniques that are typically used for wireless communication is presented.

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