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IMPROVING THE PERFORMANCE OF MOBILING COMMUNICATION USING CONVOLUTIONAL CODING WITH PILOT BITS | ||
| AL-TAQANI | ||
| Article 1, Volume 25, Issue 3, 2012, Pages 0-0 | ||
| Author | ||
| Nooreldeen Raaoof Hadi | ||
| Abstract | ||
| The major impairments of the mobile wireless communication signal are Fading and Doppler effect. To reduce these effects, channel coding is required which provides for forward error correction. This enables the receiver to correct the errors which have occurred in the transmission path. Also, a control information consists of known pilot bits may be added to support channel estimation for coherent detection. In this paper the Bit Error Rate (BER) performances is shown by means of simulation for Rayleigh fading channels with Doppler shift and Additive White Gaussian Noise (AWGN) is added. Here the convolutional code with ½ code rate is used as a channel coding technique, and sequence of pilot bits is mapped and inserted with known modulation scheme Quadrature Amplitude Modulation (QAM), these pilot bits are know to the receiver. At the receiving end coherent detection is done by channel estimating using the splited pilot bits, and then Viterbi decoding is investigated. Obviously, the results show that the performance in terms of BER of coded signal is much better when inserting pilot bits during signal modulation. To compensate the loss in spectrum efficiency and data rate, the use of QAM modulations with larger size constellation is suggested, with small loss of performance associated with an extended constellation. The whole work is done using MATLAB. | ||
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