| 摘要: |
| 针对全球移动通信系统 (GSM) 的安全机制不能实现端到端安全通信问题，提出了一种低复杂度基于脉冲调制的数据传输方案及优化方法。分别设计了基于脉冲位置调制及脉位结合极性调制的类语音信号，给出了基于跳时脉冲的帧同步方法。搭建了基于脉冲调制的GSM语音信道数据传输仿真平台，分析比较了不同调制阶数和不同自适应多速率编码 (AMR) 码率下系统的性能。为了提高系统可靠性，引入卷积码进一步降低了系统误码率。仿真结果表明，4阶脉冲调制最适用于语音信道，所提脉冲调制方法与传统低复杂度频移键控 (FSK) 调制方式误码率近似，但传输速率高，且提出的脉位结合极性调制进一步提高了传输速率，总提高比例达到36%。 |
| 关键词: GSM语音信道 数据传输 脉冲调制 类语音信号 自适应多速率编码 |
| DOI： |
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| 基金项目:国家自然科学基金资助项目(61402044)；北京市科技新星计划项目（Z161100004916086）；北京市优秀人才资助计划青年拔尖项目(2016000026833ZK08); 北京市属高校“青年拔尖人才培养计划”（CIT&TCD201704065） |
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| A data transmission method based on pulse modulation over GSM voice channel |
| XU Zhan |
| () |
| Abstract: |
| Aiming at the problem that the security mechanism of Global System for Mobile Communications (GSM) can not realize end-to-end security communication,a data transmission scheme and optimization method based on pulse modulation with low complexity is proposed. Speech-like signals based on Pulse Position Modulation and Pulse Position Polarity Modulation schemes are designed respectively. The synchronization scheme based on time hopping pulse modulation is provided. A simulation platform of data transmission over GSM voice channel is built,and the system performances of different modulation level and adaptive multi-rate (AMR) codec with different coding rate are compared and analyzed. In order to further reduce the system error rate,the convolutional code is introduced. Simulations show that the pulse modulation with order 4 is most suitable for voice channel. The proposed pulse modulation scheme is similar to the traditional Frequency Shift Keying(FSK) modulation scheme with same bit error rate(BER) but higher transmission rate,and the proposed pulse position combined with polar modulation further improves the transmission rate,with a total improvement rate of 36%. |
| Key words: GSM voice channel data transmission pulse modulation speech-like signal adaptive multi-rate |
