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Power allocation for the multiple-channel cognitive systems is studied in this paper. Our objective is to maximize the throughput of the cognitive link while providing delay guarantee for the secondary user. By using the effective capacity theory, the problem is modeled as effective capacity maximization problem with average power constraint, which turns out to be a constrained convex optimization...
While a cognitive radio network sharing the spectrum with a primary network, one of the major concerns is that harmful interference to the primary users should be avoided. In this paper, we propose three low-complexity algorithms for distributed beamforming in cognitive radio networks which opportunistically select a subset of cognitive source nodes whose phases may be compensated, so that the received...
Cognitive radio (CR) is a promising technology to solve the spectrum scarcity problem by enabling secondary users (SU) to utilize the spectrum holes of primary users (PU) caused by static spectrum allocation. However, SUs need to avoid the interference to PUs, imposing new challenges in routing protocol designs and throughput improvement in CR networks (CRN). In this paper we propose a cross-layer...
Auction based dynamic spectrum access is an efficient approach to solve the spectrum shortage problem. However, conventional spectrum auction algorithms mainly concentrated on maximizing the revenue, under which the dynamic spectrum access (DSA) users with poorer cognitive abilities are usually hard to win the auction for spectrum access. In this paper, we propose a novel waiting-time auction (WTA)...
Spectrum sensing is performed by secondary users (SUs) to detect primary users (PUs) in cognitive radio networks. The limited time duration allocated for spectrum sensing may result in high false alarm probability, which always leads to low spectrum utilization and degrades the SU throughput. To overcome this problem, we propose a novel joint sensingtime adaption and data transmission (JSTA-DT) scheme...
In order to efficiently make use of all the spectrum resource in VHF band for aeronautic communications, Non-Continuous OFDM (NC-OFDM) scheme in VHF, named as Non-Continuous Broadband VHF (NC-B-VHF) system, is designed and evaluated in this paper. Specifically, the structure of NC-B-VHF system is presented. The critical modules to implement the applicable system are discussed and exemplified. Meanwhile,...
Carrier interferometry (CI) codes have been proposed for multi-carrier systems, e. g., orthogonal frequency division multiplex (OFDM), which achieves higher transmission rate and lower peak to average power ratio (PAPR). In this paper, non-continuous carrier interferometry (NCI) codes have been constructed for the non-continuous multi-carrier systems. In the cognitive radio system such as IEEE 802...
Non-contiguous orthogonal frequency division multiplexing (NC-OFDM) system is used in the wide-band communications, especially for the wide-band cognitive radio, e. g., IEEE 802.22. However, in the high speed mobile environment, NC-OFDM suffers from inter-carrier interference (ICI). Due to the non-uniformed Doppler spread in the wide-band, it is not efficient to use the traditional ICI cancelation...
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