SC-FDMA with Adaptive Modulation using PN-Sequence and STBC Code

Wireless communication is known as the future trends that are used to communicate between transmitter and receiver. Modulation has been done after generation of the signal in each multiple sub carriers to send it over the channel. OFDM, SCFDMA and other modulation schemes are used and reviewed. Earlier OFDM method was used but it has various disadvantages like it is sensitive to Doppler shift and frequency synchronization problems. It has high peak to average power ratio (PARP), requiring linear transmitter circuitry, which suffers from poor power efficiency. In OFDM method there is loss of efficiency caused by cyclic/guard interval. To overcome these limitations, it was advised to use various coding algorithms like STBC codes which improves efficiency or other multiple access technique like SC-FDMA method. In the proposed system modulation of the signal is performed, addition of Cyclic prefix has been done to obtain high performance data transform and use bandwidth efficiently. Proposed method evaluates STBC code to send single data to multiple routes for the quality enhancement of the signal. Transmission has been done between the receiver and the transmitter where each side involves separately performing their operations. As in the existing system FFT block was not included due to which signal has been distort whereas in the proposed system this DFT block is added before the IDFT block that will help to retain the signal quality. Comparison has been performed through taking signal and performance is evaluated in this thesis to check the efficiency of individual approach.