The integration of cognitive radio and Ultra wideband (UWB) networks has attracted lots of research interests. Cognitive UWB networks not only provide very high data rates but also guarantee the uninterrupted communic...The integration of cognitive radio and Ultra wideband (UWB) networks has attracted lots of research interests. Cognitive UWB networks not only provide very high data rates but also guarantee the uninterrupted communication of primary system operated in the same frequency band. In this work, the problem of the capacity analyses of cognitive UWB networks is investigated. Different from the conventional cognitive spectrum sharing model which can only utilize the idle spectrum hole, the cognitive UWB system can operate adaptively based on spectrum sensing results. Taking into account several factors such as the transmission power constraint of UWB, the interference constraint of the receivers in primary systems, the secondary UWB network capacity problem is modeled as a convex optimization problem over the transmission power. The optimal power allocation strategy and algorithm are derived based on this optimization problem. Two cases (Perfect Spectrum Sensing and Imperfect Spectrum Sensing) are studied in the paper. Numerical simulation results show that the proposed adaptive power allocationscheme improves the ergodic and outage capacity under both transmission power and interference constraints compared with constant transmission power scheme.展开更多
The development of optical transmission was summarized. The multiplexing system was show in detail. The concepts, characteristic, key technology, expand trend and application prospect of frequency division multiplexin...The development of optical transmission was summarized. The multiplexing system was show in detail. The concepts, characteristic, key technology, expand trend and application prospect of frequency division multiplexing, time division multiplexing, code division multiplexing and wave division multiplexing were illustrated.展开更多
In this paper, we conduct research on the developmental trend of the computer music technology under the background of multichannelstereo recording. Surround sound is not only used in the fi lm, home theater, also pen...In this paper, we conduct research on the developmental trend of the computer music technology under the background of multichannelstereo recording. Surround sound is not only used in the fi lm, home theater, also penetrated the digital TV and digital broadcasting.But because of the limitation of storage media capacity and transmission bandwidth must use all kinds of that audio compression technologyto transmit audio data. As a more general and more practical signifi cance, as masking and by masking sound are not limited to their respectiveresend by a single speaker, but in different proportion to their respective ‘channel sound level is poor. To deal with this issue, this paperintegrates the signal denoising method as the optimization and achieves better performance.展开更多
基金supported by following projects:NSFC (No. 60432040, 60972079)Beijing Natural Science Foundation (No. 4052021)+1 种基金The Research Fund for the Doctoral Program of Higher Education(No.20060013008, 200700130293)UWB-ITRC Inha University, Korea,and iCHIP Project financed by Italian Ministry of Foreign Affairs,And it is partly supported by Project iCHIP financed by Italian Ministry of Foreign Affairs
文摘The integration of cognitive radio and Ultra wideband (UWB) networks has attracted lots of research interests. Cognitive UWB networks not only provide very high data rates but also guarantee the uninterrupted communication of primary system operated in the same frequency band. In this work, the problem of the capacity analyses of cognitive UWB networks is investigated. Different from the conventional cognitive spectrum sharing model which can only utilize the idle spectrum hole, the cognitive UWB system can operate adaptively based on spectrum sensing results. Taking into account several factors such as the transmission power constraint of UWB, the interference constraint of the receivers in primary systems, the secondary UWB network capacity problem is modeled as a convex optimization problem over the transmission power. The optimal power allocation strategy and algorithm are derived based on this optimization problem. Two cases (Perfect Spectrum Sensing and Imperfect Spectrum Sensing) are studied in the paper. Numerical simulation results show that the proposed adaptive power allocationscheme improves the ergodic and outage capacity under both transmission power and interference constraints compared with constant transmission power scheme.
文摘The development of optical transmission was summarized. The multiplexing system was show in detail. The concepts, characteristic, key technology, expand trend and application prospect of frequency division multiplexing, time division multiplexing, code division multiplexing and wave division multiplexing were illustrated.
文摘In this paper, we conduct research on the developmental trend of the computer music technology under the background of multichannelstereo recording. Surround sound is not only used in the fi lm, home theater, also penetrated the digital TV and digital broadcasting.But because of the limitation of storage media capacity and transmission bandwidth must use all kinds of that audio compression technologyto transmit audio data. As a more general and more practical signifi cance, as masking and by masking sound are not limited to their respectiveresend by a single speaker, but in different proportion to their respective ‘channel sound level is poor. To deal with this issue, this paperintegrates the signal denoising method as the optimization and achieves better performance.
