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M-ary phase-silence-shift-keying (PSSK), one of power-efficient modulation schemes, has enhanced symbol error rate (SER) performance by 6 dB compared with that of the conventional phase-shift-keying (PSK). Phase tracking problem of the PSSK with phase-locked-loop (PLL) is discussed in this paper. Capacity of the PSSK for the additive white Gaussian noise (AWGN) channel and Rayleigh fading channel is analyzed. Capacity loss of the PSSK due to the PLL is small, which tells us that the PSSK demodulator can be practically implemented. 相似文献
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5G Based on Cognitive Radio 总被引:2,自引:1,他引:1
Cornelia-Ionela Badoi Neeli Prasad Victor Croitoru Ramjee Prasad 《Wireless Personal Communications》2011,57(3):441-464
Both the cognitive radio (CR) and the fifth generation of cellular wireless standards (5G) are considered to be the future technologies: on one hand, CR offers the possibility to significantly increase the spectrum efficiency, by smart secondary users (CR users) using the free licensed users spectrum holes; on the other hand, the 5G implies the whole wireless world interconnection (WISDOM—Wireless Innovative System for Dynamic Operating Megacommunications concept), together with very high data rates Quality of Service (QoS) service applications. In this paper, they are combined together into a “CR based 5G”. With this aim, two novel ideas are advanced: the 5G terminal is a CR terminal and the CR technology is chosen for WISDOM concept. Thus, the 5G takes CR flexibility and adaptability and makes the first step through a commercial and tangible form. 相似文献
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Mari Carmen Domingo 《Wireless Personal Communications》2011,57(4):607-627
The design of routing protocols for Underwater Wireless Sensor Networks (UWSNs) poses many challenges due to the intrinsic properties of underwater environments. In this paper we present DUCS (Distributed Underwater Clustering Scheme), a new GPS-free routing protocol that does not use flooding techniques, minimizes the proactive routing message exchange and uses data aggregation to eliminate redundant information. Besides, DUCS assumes random node mobility and compensates the high propagation delays of the underwater medium using a continually adjusted timing advance combined with guard time values to minimize data loss. The theoretical and simulation studies carried out demonstrate its effectiveness. 相似文献
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Aggregation convergecast scheduling in wireless sensor networks 总被引:3,自引:0,他引:3
We consider the problem of scheduling in wireless sensor networks for the purposes of aggregation convergecast. We observe that existing schemes adopt essentially a two phase approach, consisting of, first, a tree construction and, second, a scheduling phase. Following a similar approach, we propose two new improvements, one to each of the two phases. Starting with a new lower bound on the schedule length, we make use of it in the tree construction phase. The tree construction phase consists of solutions to instances of bipartite graph semi-matchings. The scheduling phase is a weight-based priority scheme that obeys dependency (tree) and interference constraints. Our extensive experiments show that, overall, our proposed solution not only outperforms all previously proposed solutions in terms of schedule length, but it also significantly extends the network’s lifetime. 相似文献