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We propose a simple method for the generation of signature matrices for a space-time spreading (STS) system with BPSK modulation, where a signature sequence assigned to a user is paritioned into segements and the segments are assigned to the transmit antennas of the user. We show that, if the signature sequences are linearly independent, the STS system does not has an error floor in its BER performance...
We propose a novel pulse for cognitive radio-ultra wideband (CR-UWB) using the compressed chirp waveforms and modified transform domain communication system (TDCS) in this paper. This pulse can sense the radio environment, and uses UWB as a versatile PHY layer to adapt various wireless channel conditions, and utilizes the interference free spectrum of any UWB masks, thereby, it can avoid interference...
For these communication systems whose transmitted waveforms have a much closed signal space, such as the attractive Ultra Narrow-band (UNB) modulation technology, it is rather toilsome to obtain the satisfactory performance because of the difficulty in accurately determining the threshold of the optimum receiver, which is mainly caused by its tiny waveform dipartition as well as the unruly DC variant...
To suppress the side-band interferences caused by multiband orthogonal frequency division multiplexing (MB-OFDM)-based cognitive radio systems, a mathematical expression of the side-band signal is derived. Based on this expression, the constraints among the transmitted symbols, which help to suppress the interferences, are obtained. Combined with the constraints, a type of block Turbo code modulation...
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