We consider the problem of distributed detection in a large network of sensors under network communication constraints. Sensor nodes are randomly deployed and follow a random sleep/wake schedule. When awake, sensor nodes perform local detection tests and communicate detections over a multiple-access channel to a fusion center. The fusion center can detect both successful communications and communication collisions in the channel. We derive fusion rules for perfect communications and a delay-constrained protocol and show that each are functions of count statistics only. We derive analytical expressions that characterize the performance of the system in terms of energy consumption and detection probability. Simulation examples compare theoretical predictions with numerical results.

关键词：通信；分布式计算；多路存取；二进制处理；碰撞；决策

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The fundamental theme for the research performed under the subject grant is the exploitation of receiver statistics that are obtained as packets are being demodulated and decoded in tactical cognitive radio networks. We employ receiver statistics to provide control information for adaptive protocols, improve soft-decision decoding, permit spectrum sensing while communicating, and form silencing sets in media access control. To accelerate protocol design and development, we derived methods to generate receiver statistics directly, which avoids time-consuming embedded simulations of the physical layer in performance evaluations of cross-layer protocols such as adaptive transmission, media access control, and routing protocols.

关键词：通信；通信和无线电系统；通信网络；通信协议；接收机；认知无线电；动态频谱接入

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This research seeks to evaluate the effectiveness of these LDPC codes in a QKD setting, while comparing real-world parameters such as runtime, throughput and communication complexity empirically with the well- known Cascade and Winnow algorithms. Additionally, the effects of inaccurate error estimation, non-uniform error distribution and varying key length on all three protocols are evaluated for identical input key strings. Analyses are performed on the results in order to characterize the performance of all three protocols and determine the strengths and weaknesses of each.

关键词：通信；密码学；算法；量子秘钥分配

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To improve the efficiency of communications among unmanned systems, the research focused on the novel use of asymmetric polarized MIMO and network availability. The dissertation objective was to maintain the highest network availability for a mobile ad hoc network with heterogeneous communication capabilities. Using a hybrid dual-polarized Rayleigh fading channel model, asymmetric antenna configurations were studied in simulation for bit error rate and capacity. For a 1 x 1 configuration, polarization reciprocity was used to exploit the polarized channel knowledge, thereby maximizing received uplink power. The optimum gains to maximize uplink capacity were also derived for varying channel cross-polarization values. Larger configurations of 2 x 1 and 2 x 2 were investigated, including overlays of orthogonal space-time block coding, which improved diversity performance in the polarized channels. Extending these link results to realistic scenarios with unmanned systems, a reference point group mobility model including large-scale propagation was proposed to compute the network availability. Lastly, four extensible formation models were analyzed for their influence on network availability.

关键词：通信；极化；瑞利波；无线通信；MIMO

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Dragonfly is a password authenticated key exchange protocol that has been submitted to the Internet Engineering Task Force as a candidate standard for general internet use. We analyzed the security of this protocol and devised an attack that is capable of extracting both the session key and password from an honest party. This attack was then implemented and experiments were performed to determine the time-scale required to successfully complete the attack.

关键词：通信；密码学；信息安全；通信协议；密钥交换协议

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We report on the theoretical and experimental progress on photonefficient quantum key distribution. We have derived theoretical bounds on the upper bound on the private capacity and developed a novel large-alphabet quantum key distribution protocol employing security through measurements in mutually unbiased bases. In experimental efforts, we advanced the photonic integrated chip architecture, including linear optics for security checks and chipintegrated high-performance single photon detectors.

关键词：通信；集成系统；量子通信；量子论；通信协议；光通信

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FEC techniques are compared for different MIMO configurations of a high altitude, extremely wide bandwidth radio frequency downlink. Monte Carlo simulations are completed in MATLAB(trade name) with the aim of isolating the impacts of turbo codes and LDPC codes on system throughput and error performance. The system is modeled as a transmit-only static array at an altitude of 60,000 feet, with no interferers in the channel. Transmissions are received by a static receiver array. Simulations attempt to determine what modulation types should be considered for practical implementation, and what FEC codes enable these modulation schemes. Results show that the best performing system configuration was unable to meet both criteria, but was capable of improving over Brueggen's 2012 research, which used Reed-Solomon codes and a MIMO configuration of 80:160, by 18.6. The best- case configuration produced a throughput rate of 0.83 Tbps at a BER of less than 1 x 10 to the minus 8th power, by implementing a rate 2/3 LDPC code with QAM constellation of 16 symbols.

关键词：通信；下行链路；无线电频率；MIMO

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In modern LEO satellite communication systems,numerous singnals have to be located in a same frequency band because of limited spectrum resources.Thus,a bandwidth-efficient modulation,which has constant envelope characteristics and can alleviate signal distortions when using saturated power amplifiers is necessary to combine several signals to share the frequency resource.This paper presents the analytic interplex modulation expression in LEO satellite spread spectrum communication systems,and obtains the relationship of modulation efficiency,error rate and power ratio.Lastly,the appropriate choice of power radio is obtained in the case of three signals or four signals multiplexing.The work of this paper is an important guideline for constant envelope combined methodologies in LEO satellite spread spectrum communication systems.

关键词：通信；恒包络；互复用；调制效率；卫星通信

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As demand for higher data-rate wireless communications increases, so will the interest in multiple-input and multiple-output (MIMO) systems. In a single transmitter, single receiver communication system, there is a fundamental limit to the data-rate capacity of the system proportional to the systems bandwidth. Since increasing the bandwidth is expensive and limited, another option is increasing the systems capacity by adding multiple antennas at the transmitter and receiver to create a MIMO communication system. With a T transmitter, R receiver MIMO communication system, TR channels are created which allow extremely high data-rates. MIMO systems are attractive because they are extremely robust as they are able to operate when encountering channels with severe attenuation also known as deep fades. MIMO systems are known for their ability to achieve extremely high data-rates created by the multiple channels while improving bit error rate (BER) through diversity.

关键词：通信；无线通信；飞船；MIMO；无线电接收机

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This study investigates the adequacy of existing mobility models in capturing various aspects of human mobility behavior (including communal behavior), as well as network protocol performance. This is achieved systematically through the introduction of a framework that includes a multi-dimensional mobility metric space. We then introduce COBRA, a new mobility model capable of spanning the mobility metric space to match realistic traces. A methodical analysis using a range of protocol (epidemic, spraywait, Prophet, and Bubble Rap) dependent and independent metrics (modularity) of various mobility models (SMOOTH and TVC) and traces (university campuses, and theme parks) is done. Our results indicate significant gaps in several metric dimensions between real traces and existing mobility models. Our findings show that COBRA matches communal aspect and realistic protocol performance, reducing the overhead gap (w.r.t existing models) from 80to less than 12, showing the efficacy of our framework.

关键词：通信；计算机网络；流动性；通信协议；无线电线路

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