【作者】 任崇玉；

【导师】 曹洁；

【作者基本信息】 兰州理工大学 ， 检测技术与自动化装置， 2008， 硕士

【摘要】 在智能交通系统的研究中,实时数据通信技术越来越重要。实时数据通信的目的是通过无线通信网络,使车辆及其使用者与交通监控中心之间能够互相交换实时交通信息,增强车载导航系统的功能。由于信道传输特性的不理想以及加性高斯白噪声的影响,在实际信道上传输数据时,所收到的数据不可避免地会产生错误。当无线网络处于拥塞状态时,短消息数据传输时延会加大,将严重影响定位的精度。本文利用纠错编码技术对数据传输的可靠性进行研究,采用(2,1,3)卷积码实现数据传输的纠错编码。论文在分析其原理的基础上,着重讨论分析了卷积码的软件实现方法。编码时充分利用DSP器件的移位和双字处理能力,使卷积编码数据能够快速有效地完成;在译码程序算法实现上,首先通过MATLAB仿真,在信道的误码率小于1%的情况下确定了Viterbi译码算法的最佳回溯深度,其次运用查表的方法,避免了大量繁琐计算,使得译码简洁迅速,译码器的实时性能良好。通过实际测试数据,验证了纠错编码的有效性,为提高数据传输的质量奠定了基础。针对短消息数据传输的时延问题,利用排队论理论对无线通信信道进行分析,建立了短消息无线数据传输的排队论模型,推导了短消息的排队长度和排队等待时间等参数,并且通过对短消息业务中心(SMSC)排队模型的MATLAB仿真验证了模型的合理性,为进行拥塞控制提供了理论依据。另外,设计了实现算法的硬件电路系统,包括电源模块、时钟模块、复位电路、JTAG仿真接口、程序存储器模块等。并对存储器的电平转换以及时钟模块的配置进行了详细的分析。更多还原

【Abstract】 In the research of intelligent transportation, the communication of real time data becomes more and more important. The communication of real time data lets vehicle and users exchange real time traffic information with traffic control center and makes the function of vehicle navigation system more effect. However, as the characteristics of the transmission are not ideal and the impacts of the additive white noise exist, in the actual channel of signal transmitting, the errors from the received signal are inevitable. When the wireless network is in the stage of congestion the delay of short message data transmitting will increase, which will affect the precision of position severely.In this thesis, the reliability of data transmitting is researched by the technology of the error correcting encoding and the convolution code (2, 1, 3) is adopted to realize encoding. The principle and software realization method of the convolution code are analyzed. When encoding, the data of the convolution code can be achieved effectively using the shift of DSP and the capability of double-word processing. During the process of decoding program realization, firstly, in the circumstance that the error-rate of channel of signal transmitting is below one percent, which is testified by MATLAB simulation, the optimal depth of backtracking of the decoding is confirmed. Then the large number of computation is void through data table, which make the decoding compact and rapid. So the characteristic of the decoding is very sound. The validity of the error correcting the encoding is testified by practical testing data, which take a foundation for improving the quality of data transmitting.As to delay of shot message data transmitting, the channel of the wireless communication is analyzed utilizing queue theory, the Short Message Queuing model is established and the parameters of short message, such as the queue length, the average waiting time etc. are deduced, the rationality of which is testified by MATLAB simulation of the model of SMSC and which provide the theory foundation of congestion control.Moreover, the hardware circuit system of realization algorithmic is designed, which includes power module, clock module, resetting module, JTAG simulation interface module, program memorizer module and so on. Otherwise, the electric level transform of memorizer and the configuration of clock module are analyzed in detail.更多还原