Performance Analysis of Adaptive Multi User OFDM
Ece Depatment · 2015
The demand for high-speed mobile wireless communications is rapidly growing. OFDM technology promises to be a key technique for achieving the high data capacity and spectral efficiency requirements for wireless communication systems of the near future. In our proposed method Adaptive modulation techniques is used for maximizing the data throughput of subcarriers allocated to a user. It measures the SNR of each subcarrier in the transmission, then selecting a modulation scheme that will maximize the spectral efficiency, while maintaining an acceptable BER. This technique has been used in Asymmetric Digital Subscriber Line (ADSL) to maximize the system throughput.In addition Adaptive user allocation improves signal power of 3-5 dB. Also in the first techniques Crest Factor (CF)is reduced by using OFDM pilot symbols ,in the second techniques reduces the CF of data carrying symbols, by including additional subcarriers