A novel OFDM transmission scheme with length-adaptive Cyclic Prefix

【Abstract】 Conventional OFDM transmission system uses a fixed-length Cyclic Prefix to counteract Inter-Symbol Inter- ferences (ISI) caused by channel delay spreading under wireless mobile environment. This may cause considerable per- formance deterioration when the CP length is less than the channel RMS delay spread, or may decrease the system power and spectrum efficiency when it is much larger. A novel Orthogonal Frequency Division Multiplexing (OFDM) transmission scheme is proposed in this paper to adapt the CP length to the variation of channel delay spread. AOFDM-VCPL utilizes the preamble or pilot sub-carriers of each OFDM packet to estimate the channel RMS delay spread; and then uses a criterion to calculate the CP length , which finally affects the OFDM transmitter. As illustrated in the simulation section, by deploying this scheme in a typical wireless environment, the system can transmit at data rate 11.5 Mb/s higher than conventional non-adaptive system while gaining a 0.65 dB power saving at the same BER performance.更多还原