We study the performance of space-time block coding in terms of different transmission matrices over Nakagami-m fading channels in multiple-input multipleoutput (MIMO) environments. A closed-form expression for the exact symbol error rate (SER) of orthogonal space-time block coding (OSTBC) over independent identically distributed Nakagami-m fading channels can be derived by means of the equivalent single-input single-output (SISO) model. The exact SERs of OSTBC with M-PSK and MQAM modulations are expressed in terms of the moment generating function (MGF) of instantaneous SNR as well as the higher transcendental functions. In this paper, we provide performance evaluation results of several codes of OSTBC with the closed-form expressions; also, Monte Carlo simulation results are given, which demonstrate the accuracy of closed-form solutions. In addition, some new observations on the performance results of different code matrices are made.

Smart antenna technology is the key technique of third generation mobile communication standard TD-SCDMA. This paper presents a scheme for designing a kind of antenna array used as smart antenna for TD-SCDMA systems. Based on the design principle of adaptive antenna array and the concept of smart antenna, a uniform circular array consisting of some antenna elements, is employed in the scheme. The antenna elements are made by using a novel coaxial collinear printed dipole structure. An optimization design of the structure, size and performance parameters of antenna elements and the antenna array is also performed by means of the global optimization algorithm. A large amount of simulation computation for the design is processed to instruct the manufacture of the experimental antenna array. A series of experimental tests are also performed to evaluate the performance of the developed antenna array with the experimental results given. The fact that experimental results are approximately in consistent with the simulation computation shows the effectiveness and feasibility of the design method. The design method proposed in this paper can be extended for the design of any other array geometry.

基于等效单输入单输出SISO (Single-input Single-output)模型，利用矩量母函数(MGF)分析法，空时分组码STBC (Space-Time Block Coding)的误符号率是可以得到其准确闭式表达式的。对于独立同分布Nakagami-m衰落信道下的空时分组码的性能进行了研究，给出了采用M-PSK和M-QAM调制方案的不同空时分组编码矩阵误符号率的闭式解以及基于闭式解的解析性能结果，通过蒙特卡洛仿真验证了闭式解的准确性。还从调制方案的角度对于几种新的空时分组码的性能进行了一些新的讨论。

在分析目前舰载通信系统存在的问题基础上，提出了将智能天线技术应用于海军舰艇的设计思想，并对将智能天线应用于舰艇上的可行性进行了论证。结果表明，此举可以大大提高舰艇电子对抗能力。最后给出了具体的实现方案。