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Conventionally, fast frequency hopping (FFH) is regarded as a non-coherent system, which has inevitable shortcomings in low spectral efficiency. To achieve a high spectral efficiency while maintaining a favourable bit error ratio (BER) performance in FFH systems, in this study, the authors extend their previously proposed subset-based coherent FFH (S-CFFH) scheme with the aid of spatial modulation...
Transform domain communication system (TDCS) is a multi- carrier cognitive radio (CR) technique which uses cyclic code shift keying (CCSK) for overlay opportunistic spectrum access. Specifically, at any given time, a TDCS system cyclically shifts a fundamental modulation waveform (i.e., a CR sequence satisfying a dynamic spectrum hole constraint) according to specific input data symbol. In practical...
Relay selection enhances the performance of the cooperative networks by selecting the links with higher capacity. Meanwhile link adaptation improves the spectral efficiency of wireless data-centric networks through adapting the modulation and coding schemes (MCS) to the current link condition. In this paper, relay selection is combined with link adaptation for distributed beamforming in a two-hop...
The existed preamble structure for orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) system requires two zero-value guard symbols to guarantee ISI and ICI avoidance (equivalent to 3/2 complex value symbols in OFDM with cyclic prefix system), which leads to OFDM/OQAM system with low spectrum efficiency. In this paper, we shorten the preamble with 1 zero-value guard symbol to improve the...
In this paper, we propose a modified preamble based channel estimation for the orthogonal frequency division multiplex/offset QAM (OFDM/OQAM). In present of multi-path effect, the inter symbol interference (ISI) always exists in the OFDM/OQAM system and the preamble based channel estimation for the conventional orthogonal frequency division multiplex with cyclic prefix (CP-OFDM) is not feasible any...
Based on the tracking control of chaotic system, the synchronization of hyperchaos in three-cell coupled quantum cellular neural network is studied; a secure communication system based on the hyperchaotic synchronization of the quantum cellular neural network is presented; its performance in the presence of channel noise is analyzed. Numerical simulations are given to illustrate the effectiveness...
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