Search

In this paper, we propose a unified and analytical approach to evaluate both interference and system performance over generalized fading channels. The analytical solution proposed is quite general, applicable to envelop and power statistics, aggregate interference of arbitrary input and signal-to-interference ratio (SIR), distributions and higher order statistics, interference and system performance over generalized fading channels including simple fading channels and composed fading channels. What enables the unification of the approach is the algebra and statistic merits of Fox's H function and distribution. Finally, the unified approach is well tested and verified by Monte Carlo simulations with controllable errors.

Frequency planning of wireless system is the ubiquitous and urgent key problem due to limited frequency spectrum. This paper presents a frequency planning method according to the characteristics of GSM-R. Rough Sets (RS) theory and Grey Clustering (GC) theory are applied in frequency planning and the factors that affect on frequency planning and their proper thresholds are discussed. Then, the optimal plan is given by means of the GC assessment. Moreover, we compare different frequency planning methods by simulations. Finally, the derivation and simulation results show that the frequency planning based on RS and GC theory is more precise than other algorithms.

Cognitive radio (CR) is a newly emerging technology proposed to improve the spectrum utilization. The interferencetolerant scenario is considered that the interfering secondary (unlicensed) terminals are spatially Poisson distributed and secondary terminals are not allowed to transmit within the interference region of primary (licensed) network. In this paper, two methods are proposed by extending and modifying the model presented in literature to analyze the outage in cognitive radio network. Instead of signal to interference ratio (SIR), interference to primary ratio (IPR) is introduced as a criterion according to the endowment of characteristic function and Laplace transform for convenience of calculation. Finally, the outage of cognitive radio network is obtained by using the fast Fourier transform (FFT) or inverse fast Fourier transform (IFFT) operation. The conclusion provided is more flexible, which includes parameters of primary network, secondary network and coexistent system. The numerical results show that the two methods proposed have similar performance and the effect when system changes parameters. But IPR and Laplace transform are more appropriate than SIR and characteristic function in the outage analysis of cognitive radio network.