一种容忍模糊参数的用频干扰分析方法

论文针对海战场装备的用频参数模糊化的现象,设计了容忍模糊输入参数的鲁棒的用频干扰分析方法的框架与流程,建立了相应的干扰分析模型。该方法能够较好地克服传统用频干扰分析技术需要理想化输入参数的限制,同时在框架流程上与目前主流的算法一致,从而继承了传统算法较高的执行效率。

Optimum weighting-coefficient-pair in inter-carrier interference self-cancellation scheme of OFDM system

As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in multi-path fading channel. However, when there are frequency offsets during the signal transmission, the inter-carrier interference （ICI） is introduced, which significantly degrades the performance. The existing ICI self-cancellation schemes such as PCC-OFDM are not optimum to minimize the interference considering both noise and ICI. In this paper, a new metric named S1NR （signal-to-interference- and-noise ratio） is proposed. We discuss the optimization issue when a constant frequency offset exists and in time-varying channels. The optimum weighting-coefficient-pair （OWCP） is obtained, which maximizes SINR theoretically through the alternant iteration algorithm. Simulations show that the performance of OWCP-OFDM is better than that of PCC-OFDM, especially when the frequency offset is large. Although the ICI self-cancellation scheme suffers bandwidth inefficiency, from the simulation results we can also see that the performance of OWCP-OFDM is much better than that of the standard OFDM systems with the same bandwidth efficiency when a frequency offset exists. Moreover, since the redundant modulation provides the capability to suppress ICI as well as a receiving SNR gain, it can be considered as exchanging the bandwidth for SNR.

Criteria for intermittent and continuous disturbance transition of ERA interaction with shaped charge jet

There are two interaction mechanisms between shaped charge jet and thin flying plate driven by explosion, that is, the intermittent and continuous disturbance. Determination of the transition criteria for the intermittent and continuous disturbance is of importance for the penetration calculation of the escaping jet and the design of ERA(explosive reactive armour). In this paper a new criteria was presented based on the analysis of interaction process, and the effects of NATO angle and thickness of flying plate on the disturbance frequency were discussed. It is shown that the critical shaped charge jet velocity increases with the plate thickness and NATO angle, especially increases drastically between 45° and 60°.

Actual implementation of spectrum-sharing systems in rayleigh fading channels~

In actual implementation of spectrum sharing systems, due to the selfishness of primary users, primary users often refuse the access of secondary users to their licensed spectrum bands even if the access of secondary users doesn＇t affect their transmission. Aimed at the selfishness problem of primary users, a seller＇s market trading mechanism is introduced which can not only stimulate primary users to tolerate larger interference power but also give the primary users an appropriate compensation at the same time, and which has very important practical significance. Based on the mechanism, the achievable maximal gross profit of secondary users and their optimal power allocation scheme in the Rayleigh fading environment are derived, and the interference price of primary users and the average revenue of secondary users＇ impact on them are also studied. Numerical calculation results are conducted to verify our theoretical results.

Cooperative Anti-Interference Spectrum Sharing with Secondary User Selection

In this paper, we propose a cooperative anti-interference spectrum sharing strategy with secondary user selection where the secondary system can gain spectrum access along with the primary system. Specifically, secondary user and are selected to transmit the primary and secondary signal through different bandwidth in the second transmission slot which occupies fraction of the time. Thus, the primary and secondary systems will not interfere with each other. We study the joint optimization of time and bandwidth allocation such that the transmission rate of the secondary system is maximized, while guaranteeing the primary system to achieve its target rate. Simulation results confirm efficiency of the proposed spectrum sharing strategy, and the significant performance improvement of the cognitive system.

ProSync： A protective synchronization scheme for NC-OFDM based opportunistic spectrum sharing system

A protective synchronization scheme （ProSync） for the non-contiguous orthogonal frequency-division multiplexing （NC-OFDM） system is proposed in this paper, aiming to minimize the impact of cross-band interference in opportunistic dynamic spectrum sharing networks. ProSync partly shrinks the preamble at the transmitter and exploits two multi-band filters at the receiver. By doing so, the potential interference suffered by NC-OFDM users, including both the cross-band interference and self interference, can be greatly reduced. Simulation results verify the effectiveness of ProSync, which is able to lower the carrier frequency offset （CFO） estimation error by up to 50%, compared with the traditional method.