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Ergodic capacity is not a suitable information-theoretic measure for delay sensitive applications over fading channels. On the other hand, delay-limited capacity becomes zero for Rayleigh channels. In this case, the Capacity with Probabilistic Delay Constraint becomes useful. In, the maximum constant source rate that may be supported in a wireless system with a probability ?? of exceeding certain...
In this paper, an energy efficient adaptive modulation scheme is proposed for a wireless cognitive radio ad hoc network, where each node is equipped with cognitive radio and the network is an OFDMA system operating on time slots. In each slot, the users with new traffic demand will sense the spectrum and locate the available subcarrier set. Then they choose subcarriers with favorable channel condition...
Constructions of multiblock space-time coding schemes that are optimal with respect to diversity-multiplexing (D-M) tradeoff when coding is applied over any number of fading blocks are presented in this correspondence. The constructions are based on a left-regular representation of elements in some cyclic division algebra. In particular, the main construction applies to the case when the quasi-static...
This work on frequency interleaved multiple access in multi-carrier system. It investigates the performance of comb type pilot symbol assist modulation for mobile reception to mitigate the effect of fast fading Rayleigh channel based on its direct estimation in frequency domain. It has been found from extensive computer simulation with different delay spread and Doppler shift, that linear interpolation...
While two-dimensional (2-D) orthogonal variable spreading factor (OVSF) codes were proposed for multicarrier direct-sequence code-division multiple-access (MC/DS-CDMA) systems in order to eliminate multiple-access interference, the number of orthogonal sequences (or code cardinality) was restricted by the number of carrier frequencies. Non-orthogonal 2-D frequency-time-spreading (FTS) codes were then...
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