Target detection by a noncooperative illuminator is a topic of general interest in the electronic warfare field. First of all, direct-path interference （DPI） suppression which is the technique of bottleneck of movin...Target detection by a noncooperative illuminator is a topic of general interest in the electronic warfare field. First of all, direct-path interference （DPI） suppression which is the technique of bottleneck of moving target detection by a noncooperative frequency modulation（FM） broadcast transmitter is analyzed in this article; Secondly, a space-time-frequency domain synthetic solution to this problem is introduced： Adaptive nulling array processing is considered in the space domain, DPI cancellation based on adaptive fractional delay interpolation （AFDI） technique is used in planned time domain, and long-time coherent integration is utilized in the frequency domain; Finaily, an experimental system is planned by considering FM broadcast transmitter as a noncooperative illuminator, Simulation results by real collected data show that the proposed method has a better performance of moving target detection.展开更多
This paper presents a new low delay centralized cooperative spectrum sensing method based on dynamic voting rule using multiple threshold level,for indoor hospital environment,where fading and direct path loss both ar...This paper presents a new low delay centralized cooperative spectrum sensing method based on dynamic voting rule using multiple threshold level,for indoor hospital environment,where fading and direct path loss both are together responsible for variation in signal strength.In the proposed algorithm,weights of Cognitive Radios(CRs)in terms of assigned votecount are estimated based on the sensed energy values with respect to multiple fixed threshold levels,so that the direct path loss can be dealt without further increasing the error,which occurs due to fading.For indoor hospital like environment,Rician fading model is more appropriate.Therefore,formulation,evaluation and analysis of various sensing performance parameters have been carried out considering Rician fading model.Comparative analysis and tradeoff among three optimum parameters-energy threshold,total number of CRs participating in sensing and total error rate,are presented with respect to signal to noise ratio(SNR).Finally,the Monte Carlo simulation is designed and implemented considering the two conditions-only fading environment and fading along with direct path loss environment.It can be observed that in both cases,the proposed spectrum sensing rule outperforms the other contemporary rules.展开更多
A graph has the unique path property UPPn if there is a unique path of length n between any ordered pair of nodes. This paper reiterates Royle and MacKay＇s technique for constructing orderly algorithms. We wish to u...A graph has the unique path property UPPn if there is a unique path of length n between any ordered pair of nodes. This paper reiterates Royle and MacKay＇s technique for constructing orderly algorithms. We wish to use this technique to enumerate all UPP2 graphs of small orders 3^2 and 4^2. We attempt to use the direct graph formalism and find that the algorithm is inefficient. We introduce a generalised problem and derive algebraic and combinatoric structures with appropriate structure. Then we are able to design an orderly algorithm to determine all UPP2 graphs of order 3^2, which runs fast enough. We hope to be able to determine the UPP2 graphs of order 4^2 in the near future.展开更多
文摘Target detection by a noncooperative illuminator is a topic of general interest in the electronic warfare field. First of all, direct-path interference （DPI） suppression which is the technique of bottleneck of moving target detection by a noncooperative frequency modulation（FM） broadcast transmitter is analyzed in this article; Secondly, a space-time-frequency domain synthetic solution to this problem is introduced： Adaptive nulling array processing is considered in the space domain, DPI cancellation based on adaptive fractional delay interpolation （AFDI） technique is used in planned time domain, and long-time coherent integration is utilized in the frequency domain; Finaily, an experimental system is planned by considering FM broadcast transmitter as a noncooperative illuminator, Simulation results by real collected data show that the proposed method has a better performance of moving target detection.
基金This research was supported by Taif University Researchers Supporting Project Number(TURSP-2020/214),Taif University,Taif,Saudi Arabia.
文摘This paper presents a new low delay centralized cooperative spectrum sensing method based on dynamic voting rule using multiple threshold level,for indoor hospital environment,where fading and direct path loss both are together responsible for variation in signal strength.In the proposed algorithm,weights of Cognitive Radios(CRs)in terms of assigned votecount are estimated based on the sensed energy values with respect to multiple fixed threshold levels,so that the direct path loss can be dealt without further increasing the error,which occurs due to fading.For indoor hospital like environment,Rician fading model is more appropriate.Therefore,formulation,evaluation and analysis of various sensing performance parameters have been carried out considering Rician fading model.Comparative analysis and tradeoff among three optimum parameters-energy threshold,total number of CRs participating in sensing and total error rate,are presented with respect to signal to noise ratio(SNR).Finally,the Monte Carlo simulation is designed and implemented considering the two conditions-only fading environment and fading along with direct path loss environment.It can be observed that in both cases,the proposed spectrum sensing rule outperforms the other contemporary rules.
基金supported in part by Project P15691 from the Austrian Federal FWF,the national science finding body,as well as by several ongoing grants from Stadt Linz,Land Obersterreich and the Austrian Federal BKA.Kunst
文摘A graph has the unique path property UPPn if there is a unique path of length n between any ordered pair of nodes. This paper reiterates Royle and MacKay＇s technique for constructing orderly algorithms. We wish to use this technique to enumerate all UPP2 graphs of small orders 3^2 and 4^2. We attempt to use the direct graph formalism and find that the algorithm is inefficient. We introduce a generalised problem and derive algebraic and combinatoric structures with appropriate structure. Then we are able to design an orderly algorithm to determine all UPP2 graphs of order 3^2, which runs fast enough. We hope to be able to determine the UPP2 graphs of order 4^2 in the near future.
