Due to that the Ultra Wide Band (UWB) technology has some attractive features like robustness to multipath fading, high data rate, low cost and low power consumption, it is widely use to implement cognitive radio netw...Due to that the Ultra Wide Band (UWB) technology has some attractive features like robustness to multipath fading, high data rate, low cost and low power consumption, it is widely use to implement cognitive radio network. Intuitively, one of the most important tasks required for cognitive network is the spectrum sensing. A framework for implementing spectrum sensing for UWB-Cognitive Network will be presented in this paper. Since the information about primary licensed users are known to the cognitive radios then the best spectrum sensing scheme for UWB-cognitive network is the matched filter detection scheme. Simulation results verified and demonstrated the using of matched filter spectrum sensing in cognitive radio network with UWB and proved that the bit error rate for this detection scheme can be considered acceptable.展开更多
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
This paper introduces a compact dual notched UWB antenna with an independently controllable WLAN notched band integrated with fixed WiMAX band-notch.The proposed antenna utilizes a slot resonator placed in the main ra...This paper introduces a compact dual notched UWB antenna with an independently controllable WLAN notched band integrated with fixed WiMAX band-notch.The proposed antenna utilizes a slot resonator placed in the main radiator of the antenna for fixed WiMAX band notch,while an inverted L-shaped resonator in the partial ground plane for achieving frequency agility within WLAN notched band.The inverted L-shaped resonator is also loaded with fixed and variable capacitors to control and adjust the WLAN notch.The WLAN notched band can be controlled independently with a wide range of tunability without disturbing the WiMAX bandnotch performance.Step by step design approach of the proposed antenna is discussed and the corresponding mathematical analysis of the proposed resonators are provided in both cases.Simulation of the proposed antenna is performed utilizing commercially available 3D-EM simulator,Ansoft High Frequency Structure Simulator(HFSS).The proposed antenna has high selectivity with experimental validation in terms of reflection coefficient,radiation characteristics,antenna gain,and percentage radiation efficiency.The corresponding measured frequency response of the input port corresponds quite well with the calculations and simulations in both cases.The proposed antenna is advantageous and can adjust according to the device requirements and be one of the attractive candidates for overlay cognitive radio UWB applications and URLLC service in 5G tactile internet.The proposed multifunctional antenna can also be used for wireless vital signs monitoring,sensing applications,and microwave imaging techniques.展开更多
According to the problem of cognitive ultra wide-band （UWB） spectrum sensing, a novel UWB pulse signal detection algorithm based on cumulative sum （CUSUM） test is proposed in this paper. Based on the analysis of t...According to the problem of cognitive ultra wide-band （UWB） spectrum sensing, a novel UWB pulse signal detection algorithm based on cumulative sum （CUSUM） test is proposed in this paper. Based on the analysis of the existing spectrum sensing schemes for cognitive UWB system, some obvious facts are obtained that it is difficult to detect UWB pulse signal with conventional spectrum sensing schemes, due to its low average signal to noise ratio （SNR）, large bandwidth, and low duty ratio. In this paper the detection algorithm of signal distribution change, which is application of CUSUM test, is considered to be applied to cognitive UWB spectrum sensing. But CUSUM test request that the pre-change and the post-change distributions are i.i.d, which cannot be satisfied in the detection process of UWB pulse signal. Since there are two time domain descriptions on UWB pulse signal, namely one contains only noise and the other one contains pulse signal plus noise, the existing detection algorithm of signal distribution change cannot be directly applied to detect UWB pulse signal. Hence the uniform probability density function expression of UWB pulse signal is first deduced, then CUSUM test is applied to cognitive UWB spectrum sensing. The proposed algorithm is a time sequential detection algorithm, with low complexity and minimal detection delay, which is suitable to detect the low duty ratio signal. Its performance is evaluated through theoretical analysis and numerical simulations. It is shown that this algorithm outperforms the conventional energy detection algorithm and conquers SNR wall phenomenon.展开更多
With the progress of research on cognitive radio in ultra-wideband(UWB)open frequency-band,a joint detection algorithm integrating the energy and bispectrum detection is proposed in detail for non-Gaussian signal dete...With the progress of research on cognitive radio in ultra-wideband(UWB)open frequency-band,a joint detection algorithm integrating the energy and bispectrum detection is proposed in detail for non-Gaussian signal detection from Gaussian noise.The performance of the algorithm was evaluated by simulation,the result of which indicates that the joint detection not only solves the problem of the signal detection in low signal-to-noise ratio(SNR)but also improves the operational speed and the detection probability.Thus,the joint detection algorithm has definite prospect in practice.展开更多
文摘Due to that the Ultra Wide Band (UWB) technology has some attractive features like robustness to multipath fading, high data rate, low cost and low power consumption, it is widely use to implement cognitive radio network. Intuitively, one of the most important tasks required for cognitive network is the spectrum sensing. A framework for implementing spectrum sensing for UWB-Cognitive Network will be presented in this paper. Since the information about primary licensed users are known to the cognitive radios then the best spectrum sensing scheme for UWB-cognitive network is the matched filter detection scheme. Simulation results verified and demonstrated the using of matched filter spectrum sensing in cognitive radio network with UWB and proved that the bit error rate for this detection scheme can be considered acceptable.
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.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2019R1A4A1023746,No.2019R1F1A1060799)the Strengthening R&D Capability Program of Sejong University.
文摘This paper introduces a compact dual notched UWB antenna with an independently controllable WLAN notched band integrated with fixed WiMAX band-notch.The proposed antenna utilizes a slot resonator placed in the main radiator of the antenna for fixed WiMAX band notch,while an inverted L-shaped resonator in the partial ground plane for achieving frequency agility within WLAN notched band.The inverted L-shaped resonator is also loaded with fixed and variable capacitors to control and adjust the WLAN notch.The WLAN notched band can be controlled independently with a wide range of tunability without disturbing the WiMAX bandnotch performance.Step by step design approach of the proposed antenna is discussed and the corresponding mathematical analysis of the proposed resonators are provided in both cases.Simulation of the proposed antenna is performed utilizing commercially available 3D-EM simulator,Ansoft High Frequency Structure Simulator(HFSS).The proposed antenna has high selectivity with experimental validation in terms of reflection coefficient,radiation characteristics,antenna gain,and percentage radiation efficiency.The corresponding measured frequency response of the input port corresponds quite well with the calculations and simulations in both cases.The proposed antenna is advantageous and can adjust according to the device requirements and be one of the attractive candidates for overlay cognitive radio UWB applications and URLLC service in 5G tactile internet.The proposed multifunctional antenna can also be used for wireless vital signs monitoring,sensing applications,and microwave imaging techniques.
基金supported by the Aviation Science Fund (20095596014)
文摘According to the problem of cognitive ultra wide-band （UWB） spectrum sensing, a novel UWB pulse signal detection algorithm based on cumulative sum （CUSUM） test is proposed in this paper. Based on the analysis of the existing spectrum sensing schemes for cognitive UWB system, some obvious facts are obtained that it is difficult to detect UWB pulse signal with conventional spectrum sensing schemes, due to its low average signal to noise ratio （SNR）, large bandwidth, and low duty ratio. In this paper the detection algorithm of signal distribution change, which is application of CUSUM test, is considered to be applied to cognitive UWB spectrum sensing. But CUSUM test request that the pre-change and the post-change distributions are i.i.d, which cannot be satisfied in the detection process of UWB pulse signal. Since there are two time domain descriptions on UWB pulse signal, namely one contains only noise and the other one contains pulse signal plus noise, the existing detection algorithm of signal distribution change cannot be directly applied to detect UWB pulse signal. Hence the uniform probability density function expression of UWB pulse signal is first deduced, then CUSUM test is applied to cognitive UWB spectrum sensing. The proposed algorithm is a time sequential detection algorithm, with low complexity and minimal detection delay, which is suitable to detect the low duty ratio signal. Its performance is evaluated through theoretical analysis and numerical simulations. It is shown that this algorithm outperforms the conventional energy detection algorithm and conquers SNR wall phenomenon.
文摘With the progress of research on cognitive radio in ultra-wideband(UWB)open frequency-band,a joint detection algorithm integrating the energy and bispectrum detection is proposed in detail for non-Gaussian signal detection from Gaussian noise.The performance of the algorithm was evaluated by simulation,the result of which indicates that the joint detection not only solves the problem of the signal detection in low signal-to-noise ratio(SNR)but also improves the operational speed and the detection probability.Thus,the joint detection algorithm has definite prospect in practice.
