In this letter, we address the performance analysis of underlay selective decode-and-forward (DF) relay networks in Rayleigh fading channels with non-necessarily identical fading parameters. In particular, a novel result on the outage probability of the considered system is presented. Monte Carlo simulations are performed to verify the correctness of our exact closed-form expression. Our proposed analysis can be adopted for various underlay spectrum sharing applications of cognitive DF relay networks.
The closed-form expressions for outage probability, bit error rate, and ergodic capacity of spectrum sharing-based multi-hop decode-and-forward relay networks in non-identical Rayleigh fading channels are derived. Utilizing these precise and tractable analytical formulas, we can study the impact of key network parameters on the performance of cognitive multi-hop relay networks under interference constraints. The analytical expressions are verified by Monte-Carlo simulations.
The performance of two-way amplify-and-forward (AF) relay networks is presented. In particular, we derive exact closed-form expressions for symbol error rate (SER), average sum-rate, and outage probability of two-way AF relay systems in independent but not identically distributed (i.n.i.d.) Rayleigh fading channels. Our analysis is validated by a comparison against the results of Monte-Carlo simulations.
The basic playout scheme (BAS) is designed not to take into account network impairment information during silence periods. We propose a jitter-robust playout mechanism (RST), which uses silence description (SID) packets. The lateness loss percentages are compared between the BAS and the RST algorithms. We report that the accuracy of the playout schedule calculation in the BAS is getting worse as the previous silence interval increases and our proposed RST algorithm is more effective in removing high jitter than the BAS. Under high jitter Internet conditions, the accuracy of the estimates and therefore the resulting of VoIP playout quality can be significantly improved by using the SID packets in the playout schedule recalculation.
The end-to-end performance of dual-hop multiple-input multiple-output (MIMO) decouple-and-forward relaying with orthogonal space-time block code (OSTBC) transmission over Nakagami-m fading is analyzed. By considering the multiple antennas at all nodes, we derive exact closed-form and asymptotic expressions for the outage probability and symbol error rate, which enables us to evaluate the exact performance and reveals the diversity gains of the considered system. In addition, the closedform approximation and asymptotic expressions for the ergodic capacity are also derived. We show that OSTBC transmission over relay systems yields a unit order of multiplexing gain despite the fact that full diversity order, which is equal to the minimum fading severity between the two hops, is achieved.
Satellite beam-switching problems are studied where there are m up-link beams, n down-link beams and multiple carriers per beam. By augmenting a traffic matrix with an extra row and column, it is possible to find a sequence of switching modes ((0, 1)-matrices with generally multiple unit entries in each row and column) that realize optimal transmission time. Switching modes generated are shown to be linearly independent. The number of switching modes required for an m x n matrix is bounded by (m - 1)(n - 1) + 1. For an augmented (m + 1) x (n + 1) matrix, the bound is then mn + 1. The bounds on the number of switching modes and the computational complexity for a number of related satellite transmission scheduling problems are lowered. In simplified form, the results (particularly the linear independence of permutation matrices generated) apply to algorithmic decomposition of doubly stochastic matrices into convex combinations of permutation matrices.