We propose a new scheme on modulating the lasing performance of a quantum dot-cavity system. Compared to the conventional above-band pump, in our new scheme an additional resonant driving field is applied on the quant...
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We propose a new scheme on modulating the lasing performance of a quantum dot-cavity system. Compared to the conventional above-band pump, in our new scheme an additional resonant driving field is applied on the quantum dot-cavity system. By employing the master equation theory and the Jaynes-Cummings model, we are able to study the interesting phenomenon of the coupling system. To compare the different behaviors between using our new scheme and the conventional method,we carry out investigatioin for both the 'good system'and 'more realistic system', characterizing several important parameters, such as the cavity population, exciton population and the second-order correlation function at zero time delay. Through numerical simulations,we demonstrate that for both the good system and more realistic system, their lasing regimes can be displaced into other regimes in the presence of a resonant driving field.
In this paper, we investigate energy-efficient resource allocation in a wireless powered backscatter communicationnetwork (WPBCN), which consists of two types of wireless devices. To fully exploit the information tra...
ISBN:
(纸本)9781538678657;9781538678640
In this paper, we investigate energy-efficient resource allocation in a wireless powered backscatter communicationnetwork (WPBCN), which consists of two types of wireless devices. To fully exploit the information transmission time, the two devices are supported to operate in different modes, i.e., the harvest-then-transmit (HTT) mode and backscatter communication (BackCom) mode, respectively. To improve the efficiency of wireless power transfer, energy beamforming technique is adopted at the PB. We formulate the system energy efficiency (EE) maximization problem by jointly optimizing the energy beamforming vector, power allocation, and time allocation. Since the formulated problem is non-convex, we employ variable substitutions, fractional programming theory, and semi-definite relaxation (SDR) to transform the non-convex problem into a convex problem. An algorithm is finally proposed to derive the optimal solution. Simulation results show that the proposed resource allocation scheme can improve the system EE.
Quantum key distribution (QKD) offers a secret way to share keys between legitimate users which is guaranteed by the law of quantum mechanics. Most recently, the limitation of transmission distance without quantum rep...
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The measurement-device-independent quantum key distribution (MDI-QKD) possesses the highest security among all practical quantum key distribution protocols. However, existing multiintensity decoy-state methods may cau...
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Due to the frequency reuse in 5G enhanced satellite communications, advanced spectrum management would be acquired to improve the spectrum efficiency, with the interference mitigation caused by the frequency conflict ...
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ISBN:
(数字)9781728109602
ISBN:
(纸本)9781728109619
Due to the frequency reuse in 5G enhanced satellite communications, advanced spectrum management would be acquired to improve the spectrum efficiency, with the interference mitigation caused by the frequency conflict in the manner of spectral sharing. To this end, cognitive radio (CR) has brought into the widespread attention, which aims at detection of spectrum holes by using the information collected from the secondary users (SUs). Specifically, considering the characteristics of satellite channels, the detection of spectrum holes would be more difficult in high dynamic situation. In this paper, we propose an efficient spectrum sensing scheme by taking advantage of the cooperation of satellites and base stations. Firstly, each base station (BS) receives the sensing information collected by its associated SUs. Then, a channel estimation algorithm based on fuzzy neutral network (FNN) is designed with the real-time sampling and historical data stored at BS. After that, the optimal probability of detection can be determined using fuzzy inference system (FIS) with the available sensing set. Additionally, the cooperative spectrum sensing results would be uploaded to the satellites, providing information for the further frequency allocation at the satellites' side. Finally, simulation results reveal the performance gain of the proposed algorithm in terms of the detection probability of spectrum hole.
We propose a three-party quantum secure direct communication (QSDC) protocol with hyperentanglement in both spatial-mode and polarization degrees of *** secret message can be encoded independently with desired unitary...
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We propose a three-party quantum secure direct communication (QSDC) protocol with hyperentanglement in both spatial-mode and polarization degrees of *** secret message can be encoded independently with desired unitary operations in two degrees of *** this protocol,a party can synchronously obtain the other two parties' *** with previous three-party QSDC protocols,our protocol has several ***,the single photons in our protocol are only required to transmit for three *** advantage makes this protocol simple and ***,Alice and Bob can send different secret messages to Charlie,***,with hyperentanglement,this protocol has a higher information capacity than other protocols.
An optical encryption scheme based on a ghost imaging system with disordered speckles is proposed to obtain a higher security with a small key. In the scheme, Alice produces the random speckle patterns and obtains the...
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An optical encryption scheme based on a ghost imaging system with disordered speckles is proposed to obtain a higher security with a small key. In the scheme, Alice produces the random speckle patterns and obtains the detection results with the help of a computational ghost imaging(CGI) system. Then Alice permutes the order of the random speckle patterns and shares the permutation sequence as a secure key to the authorized users. With the secure key, Bob could recover the object with the principle of the CGI system, whereas, the unauthorized users could not obtain any information of the object. The numerical simulations and experimental results show that the proposed scheme is feasible with a small key, simultaneously,it has a higher security. When the eavesdropping ratio(ER) is less than 40%, the eavesdropper cannot acquire any useful information. Meanwhile, the authorized users could recover completely with the secure key.
Traditional speech-related identity recognition commonly pays attention to individual aspect of speech signals but in reality, the speech signals are made up of semantics, speaker dependent features,
ISBN:
(纸本)9781467389808
Traditional speech-related identity recognition commonly pays attention to individual aspect of speech signals but in reality, the speech signals are made up of semantics, speaker dependent features,
This paper proposes a beamforming (BF) scheme based on multi-objective optimization (MOO) for a cognitive satellite-terrestrial network (CSTN), where the eavesdroppers (Eves) attempt to intercept the private message c...
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In this paper, we investigate a power allocation scheme in downlink multi-carrier non-orthogonal multiple access (MC-NOMA) systems for maximizing weighted sum-rate. Taking user-priority into account, we add the weight...
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