Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
Fast-Than-Nyquist (FTN) transmission is a promising method to improve the\nspectrum efficiency for future wireless communication systems. However, this\nbenefit of FTN is at the price of inducing the inter-symbol interference (ISI),\nwhich increases the complexity of the receiver. In this paper, a circulated\nblock transmission scheme for FTN signaling, i.e. CB-FTN system is proposed.\nThe detail implementation structure of CB-FTN transceiver is presented,\nin which the ISI caused by FTN transmission is canceled by the frequency-\ndomain equalization (FDE), and the inter-block interference (IBI)\ncaused by the multi-path channel is overcome by the cyclic-prefix. The postprocessing\nsignal to noise ratio (pSNR) is analyzed for the CB-FTN receiver\nwith zero-forcing FDE in AWGN channel, which is verified by the simulation\nresults. Moreover, the BER performances and computational complexity of\nCB-FTN system are compared with the existed scheme....
Carrier aggregation (CA) is considered to be a potential technology in next generation wireless communications.\nWhile boosting system throughput, CA has also put forward challenges to the resource allocation problems. In this\npaper, we firstly construct the energy efficiency optimization problem and prove that the function is strictly quasi\nconcave. Then we propose a binary search-based power allocation algorithm to solve the strictly quasi concave\noptimization problem. Simulation results show that the proposed algorithm can greatly improve the system energy\nefficiency while keeping low computation complexity....
In terms of modern applications of wireless sensor networks in smart cities, relay terminals can be employed to\nsimultaneously deliver both information and energy to a designated receiver by harvesting power via radio frequency\n(RF). In this paper, we propose time switching aware channel (TSAC) protocol and consider a dual-hop full-duplex (FD)\nrelaying system, where the energy constrained relay node is powered by RF signals from the source using decodeand-\nforward (DF) relaying protocols. In order to evaluate system performance, we provide an analytical expression of\nthe achievable throughput of two different communication modes, including instantaneous transmission and delayconstrained\ntransmission. In addition, the optimal harvested power allocation policies are studied for these transmission\nmodes. Most importantly, we propose a novel energy harvesting (EH) policy based on FD relaying which can substantially\nboost the system throughput compared to the conventional half-duplex (HD) relaying architecture in other transmission\nmodes. Numerical results illustrate that our proposed protocol outperforms the conventional protocol under the\noptimal received power for energy harvesting at relay. Our numerical findings verify the correctness of our derivations\nand also prove the importance of FD transmission mode....
The multiuser switched diversity (MUSwiD) selection schemes are useful in reducing the required channel estimation\nload in wireless networks. In this paper, we propose and evaluate the performance of cognitive amplify-and-forward\n(AF) MUSwiD relay networks where a cognitive user is selected among a set of users for data reception. The selection\nprocess is performed such that the end-to-end (e2e) signal-to-noise ratio (SNR) of the selected user satisfies a\npredetermined switching threshold. Such a user that satisfies this threshold is scheduled instead of the best user to\nreceive its message from the secondary source. In the proposed system, we consider a cognitive source, a cognitive\nrelay, a set of cognitive users, and a primary user. In this paper, an upper bound on the e2e SNR of a user is used in\nderiving of closed-form approximations for the outage probability and average symbol error probability (ASEP) of the\nstudied system in addition to deriving the ergodic channel capacity. To get more about system insights, the\nperformance is studied at the high SNR regime where approximate expressions for the outage probability, SEP,\ndiversity order, and coding gain are derived. The derived analytical and asymptotic expressions are verified by\nMonte-Carlo simulations, and some numerical examples are provided to illustrate the effect of some parameters such\nas number of users and switching threshold on the system performance. Findings illustrate that the diversity order of\nthe studied cognitive AF multiuser switched diversity relaying network is the same as its non-cognitive counterpart.\nAlso, results show that the asymptotic results tightly converge to the exact ones, and the analytical bounds are indeed\nvery tight, validating the accuracy of our approach of analysis. Furthermore, findings illustrate that the proposed\nMUSwiD user selection schemes are efficient in the range of low SNR values, which makes them attractive options for\npractical implementation in emerging mobile broadband communication systems. In contrast, these selection\nschemes are shown to be inefficient in the range of high SNR values where the multiuser diversity gain is noticeably\ndegraded when they are implemented....
Device-to-device (D2D) communication has been widely studied to improve network performance and considered as a potential\ntechnological component for the next generation communication. Considering the diverse users� demand, Quality of Experience\n(QoE) is recognized as a new degree of user�s satisfaction for media service transmissions in the wireless communication.\nFurthermore, we aim at promoting user�s Mean of Score (MOS) value to quantify and analyze user�s QoE in the dynamic cellular\nnetworks. In this paper, we explore the heterogeneous media service distribution in D2D communications underlaying cellular\nnetworks to improve the total users� QoE. We propose a novel media service scheme based on different QoE models that jointly\nsolve the massive media content dissemination issue for cellular networks.Moreover,we also investigate the so-calledMedia Service\nAdaptive Update Scheme (MSAUS) framework to maximize users� QoE satisfaction and we derive the popularity and priority\nfunction of differentmedia serviceQoE expression. Then, we further designMedia Service Resource Allocation (MSRA) algorithm\nto schedule limited cellular networks resource,which is based on the popularity function to optimize the total users�QoE satisfaction\nand avoid D2D interference. In addition, numerical simulation results indicate that the proposed scheme is more effective in cellular\nnetwork content delivery, which makes it suitable for various media service propagation....
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