In this letter, a non-orthogonal multiple access (NOMA) scheme is employed for irregular repetition slotted ALOHA (IRSA). Specifically, packet replicas are transmitted with discrete power levels, which pre-determined by the NOMA scheme. case, most collisions can be resolved in domain, contributing to much lower loss rate. Density evolution analysis formulated and degree distributions optimized different numbers of levels. The simulation results validate our show that proposed outperform...

In order to investigate the benefit of multiple-input multiple-output (MIMO) technique applying high altitude platform (HAP), a 2×2 MIMO statistical model, which can accurately describe channel between HAP and high-speed train, is presented. And dual polarization diversity particularly considered. Based on first-order three-state Markov chain, single-input single-output (SISO) channel, subset first established. The ray tracing approach applied digital relief model (DRM) covers railway Xi'an...

In this paper, we mainly research on the QoS (Quality of Service) routing algorithms for MEO/LEO (medium Earth orbit/low orbit) double-layered satellite networks. type networks, rapidly changing network topology due to relative motion satellites is one main challenges when designing an efficient algorithm. Specifically, issues high rerouting overhead and traffic with diverse requirements remain be resolved. This paper proposed a M-BMDP (modified bandwidth constrained minimum delay path)...

Seamless handoff in integrated satellite-terrestrial systems is one of the main challenges to achieve real anytime, anywhere communication. Multiple parameters have be considered instead only received signal strength. In this paper we propose two vertical decision algorithms based on classical Attribute Decision Making (MADM) methods and fuzzy logic respectively. The proposed can meet QoS (Quality Service) requirements different types application optimize system performance. are compared...

In order to maximize the available data rate and spectrum utilization efficiency, a high-throughput satellite communication system adopts full reuse scheme, which will cause serious co-frequency interference. this paper, forward link model, considering effects of free space loss, rainfall attenuation, beam gain, is established, classical low-complexity zero-forcing precoding algorithm improved in solve Moreover, regularized influence noise studied, low complexity dirty paper proposed, whose...

Simplified packet reception models such as collision model are usually adopted for optimizing irregular repetition slotted ALOHA (IRSA), which may lead to performance penalty due its poor accuracy. In this letter, we consider the problem of online IRSA optimization in finite frame length regime using a more accurate model. order allow fast IRSA, present new method based on Bayesian with Gaussian processes. Our finds optimal user degree distribution minimizing loss rate (PLR) an iterative...

Abstract In order to deal with the difficulty of spectrum sensing in cognitive satellite wireless networks, a large-scale network algorithm based on big data analysis theory is studied, and new using mean exponential eigenvalue proposed. This approach fully uses all eigenvalues sample covariance matrix results make decision, which can effectively improve detection performance without obtaining prior information from licensed users. Through simulation, various large scale radio algorithms...