Computationally efficient block transmission systems with and without guard periods

Block transmission systems using OFDM (orthogonal frequency domain multiplexing) are known for their computational efficiency in dealing with time dispersive, wireless channels. The efficiency relies primarily on data blocking by cyclic prefixing and on the exploitation of the eigenvalue decomposition of circulant channel matrices. Based on other blocking techniques and on other efficient matrix decompositions, further computationally efficient block transmission systems can be established. However, all these block transmission systems, including OFDM based systems, require the insertion of guard periods at the transmitter side, which unfavorably affects the spectral efficiency and the transmission power. We present overlapping methods that can efficiently avoid the insertion of guard periods in those systems. The measured bit error rates of the block transmission systems without guard periods are over a wide range of EB/N0EB/N0 values similar to the respective systems with guard periods. Additionally, the systems with guard period require more transmission energy to reach a similar EB/N0EB/N0 value at the receiver. The block processing is very similar for transmissions with and without guard periods, which can be reasonably exploited in a transceiver, capable to transmit and receive data blocks with and without guard periods.