脉冲位置编解码方式映射模型及效率分析

Mapping Model and Efficiency Analysis of Pulse Position Encoding and Decoding Methods

随着石油钻井工程各项技术的飞速发展,MWD、LWD及旋转导向等系统井下测量数据越来越多。为了实现井下测量数据快速有效传输,需优化编码调制方式分析泥浆脉冲信号的解码效率和数据传输速率。通过对比几种常用的编解码方式,可以了解脉冲位置编解码方式的原理、框架结构和编译计算过程。针对此种编码方式,提出了脉冲数K和时间帧数M之间的组合码关系,映射了对应关系的数学模型;并利用数据分析了快型和慢型两种组合方式的差异性,推导了编码效率计算方法;进一步计算分析快型和慢型两种方式的传输速率的差别,最后,通过软件对解码方式进行了实现。

With the rapid development of oil drilling engineering technologies,the downhole measurement data of MWD,LWD,and rotary steering systems are increasing.In order to achieve a fast and effective transmission of downhole measurement data,it is necessary to optimize the encoding and modulation method to analyze the decoding efficiency and data transmission rate of mud pulse signals.This article compares several commonly used encoding and decoding methods,and focuses on introducing the principle,frame structure,and calculation process of the pulse position encoding method.A combination code relationship between pulse number K and time frame number M is proposed for this encoding method,and a mathematical model of the corresponding relationship is mapped.The differences between the combination methods of the fast and slow modes are analyzed using data,and the calculation method for encoding efficiency is derived.Further calculation and analysis are conducted on the difference in transmission rates between fast and slow modes.Finally,the decoding method is implemented through software.