Realization of next generation multimedia PHS system

为了实现下一代多媒体PHS，使网络接入速率超过20 Mb/s，本研究取得了以下研究成果.在室内和室外环境中进行了包括功率延迟分布测量在内的无线电传播测量。同时，对室外环境下的误码性能进行了测试，揭示了室外环境下误码的原因。在室外环境中的测试结果表明，该系统的延迟扩展约为100 ns。在室内环境中，0.5ns分辨率的超延迟分辨率测量表明，直接使用测量的延迟分布数据的传输质量的计算机模拟的可能性。这将被认为是简化室内环境中传播模型的建立.基于并行虚拟机的计算机仿真揭示了室内无线环境下OFDM系统参数优化的可能性。还有，电脑 ...更多信息 基于室内无线电环境中测量的延迟分布的仿真已经示出了由于超延迟分辨率而直接使用测量数据的可能性.基于MMAC-HiSWAN的真实的硬件系统已经被开发来估计所提出的符号定时同步电路。室外环境下的现场测试证实了其良好的误比特率性能，并可以通过时延分布特性来评估其性能.为了实现移动的多媒体PHS，基于正交信道干扰检测方法研究了OFDM系统中的符号同步问题。计算机仿真结果表明，该方法有效地改善了FFT定时同步。根据这一原理，设计了一种基于神经网络的自适应判决电路，可以有效地补偿多径传播引起的直流偏移引起的线性失真.为了适应传输质量的瞬时变化，提出了一种基于DAPSK-COFDM系统的自适应传输速率系统。计算机仿真结果表明，与基于硬判决Viterbi译码器的码合并分集接收系统相结合，该系统的性能非常有效.最后，结合空间分集支路，提出了一种包含Viterbi码合并器的自适应传输速率DAPSK-COFDM系统。在建立计算机仿真系统后，将讨论其性能。少

In order to realize the next generation multi-media PHS enabling network access at more than 20Mb/s, the following research results have been obtained by this research work.1. The radio propagation measurement including power delay profile measurement have been done in both indoor and outdoor environments. At the same tune, bit error rate performance has also been measured to reveal the reason of the errors in outdoor environment. The results in outdoor environment have shown the delay spread of about 100ns. In indoor environment, an ultra delay resolution measurement with 0.5ns resolution has shown the possibility of the direct use of the measured delay profile data for computer simulation of transmission quality. This will be considered to ease the establishment of propagation model in indoor environments.2. Computer simulation based on the parallel virtual machine has revealed the possibility of the system parameter for OFDM system in indoor radio environment. And also, the computer … More simulation based on the measured delay profile in indoor radio environment has shown the possibility of the direct use of measured data due to the ultra delay resolution.3. The real hardware system based on the MMAC-HiSWAN has been developed to estimate the proposed symbol timing synchronization circuit. Field test in outdoor environments have confirmed the good bit error rate performance and made possible to evaluate the performance by delay profile characteristics.4. In order to enable the mobile multi-media PHS, the symbol synchronization problem in OFDM system has been researched based on the orthogonal channel interference detecting method. The computer simulation results have shown the effective improvement in FFT timing synchronization. This principle has been followed to develop an adaptive decision circuit based on a neural network which can effectively compensate the linear distortion caused by the DC offset due to multipath propagation.5. For adopting the instantaneous variation of transmission quality, an adaptive transmission rate system based on DAPSK-COFDM system has been proposed. The computer simulation results have shown that the performance of the proposed system is very effective when combined with code-combining diversity reception system based on hard decision Viterbi decoders.6. And finally, combining with space diversity branches, the proposed adaptive transmission rate DAPSK-COFDM system including Viterbi code combiner has been proposed. Its performance will be discussed after constructing the computer simulation system. Less