Avoidance of guard periods in block transmission systems

To meet the requirement of efficient cancellation of intersymbol interference (ISI) in high data rate transmissions over time dispersive channels block based transmissions are often adopted. This is the case in orthogonal frequency domain multiplexing (OFDM), cyclic prefix based single carrier (CP-SC) and block transmissions with null guard periods (ZP-SC). Guard periods are inserted between the data blocks that lower the spectral efficiency significantly. In this paper techniques are presented and analyzed that aim at omitting the guard periods in the aforementioned systems without increasing the computational complexity significantly. One is the application of overlapping methods, another the reasonable selection of the block size, a third the usage of guard periods shorter than the initial ones. The techniques can be combined arbitrarily. They are applied in transmissions over a mobile vector channel and assessed in terms of bit error rate (BER), spectral efficiency and computational complexity.