Experimental research on a mobile receiver with high sensitivity for the terrestrial digital television broadcast signals

本研究涉及一种分集合并方案，其中将分集技术与纠错译码相结合，以尝试改善移动接收的性能。在本报告中，总结了为评估该方案的性能而进行的研究的结果。起初，已经计划了硬件实施，但由于成本高于预期，该计划已被放弃。为了模拟分集译码方案的性能，开发了具有软穿戴功能的虚拟接收机。对分集译码方案在不同环境下的性能进行了评估。主要研究内容如下：(1)研究了OFDM信号的符号同步方案；(2)瑞利衰落环境下的性能评估；(3)多径环境下的性能评估；(4)数字电视系统中实际采用的删余卷积码系统的性能评估；(5)用简单的M算法代替维特比算法时的性能评估；(6)模拟接收和传输路径的软件开发。虽然我们还不能达到硬件开发和实验的目的，通过软磨损验证了分集译码方案的性能和有效性。分集译码方案的概念被认为适用于除地面数字电视广播和ofdm系统之外的各种移动通信系统。我们将努力开发简化的解码过程和改进的方案，希望有机会实现硬件，以确保有效性的目的。

This research is concerned with a diversity combining scheme in which the diversity technique is combined with error correcting decoding in an attempt to improve the performance with a mobile reception. In this report, the results of the research conducted to evaluate the performance of the scheme are summarized. In the beginning, a hardware implementation had been planned, but this plan had been given up for the reason of the cost higher than expected. In stead the virtual receiver has been developed with soft wears to simulate the behavior of the performance of the diversity decoding scheme. The performance of the diversity decoding scheme has been evaluated under various environments. The conducted research items are as follows : (1)Research on the symbol synchronization schemes for OFDM signals, (2)Performance evaluation under Rayleigh fading environment, (3)Performance evaluation under multipath environment, (4)Performance evaluation for the system applying a punctured convolutional code actually adopted in the digital TV system, (5)Performance evaluation when applying a simple M-algorithm in place of Viterbi algorithm, (6) Development of, soft wares to simulate the receiver and the propagation path.Although we could not fulfill the object of the hard wear development and experiment, we could verify the performance and effectiveness of the diversity decoding scheme with the soft wear. The concept of the diversity decoding scheme is considered to be applicable to various mobile communication systems besides the terrestrial digital TV broadcast and OFDM systems. We will make an effort to develop a simplified decoding process and an improved scheme hoping to have a chance to implement a hard ware for the purpose of ensuring the effectiveness.