User:Bhatnagarmanav/sandbox

Double differential modulation: In the single-differential modulation based communication system, the receiver assumes that the channel is constant over at least two consecutive time intervals. However, the flat fading wireless channel does not remain constant over two consecutive time intervals In the presence of carrier offsets and these differential schemes experience substantial performance loss. Double-differential (DD) modulation is a technique to avoid the effect of carrier frequency offset. In the DD modulation the decoder uses three consecutively received data samples for decoding the current symbol contrary to the single-differential modulation. Two levels of single-differential modulation are employed at the transmitter and a simple heuristic decoder can be used at the receiver. Symbol error rate (SER) expressions for the double-differentially modulated data over Rayleigh and Ricean fading SISO channels with carrier offsets are provided in. The DD modulation can also be applied to the multiple-input multiple-output (MIMO) systems. </ref>