Variable Length Preamble for Human Body Communication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Human body communication faces challenges with low spectral efficiency and high bit error rates due to anisotropic radio wave transmission and interference from the environment, which are exacerbated by the use of frequency selective digital transmission schemes and filters that cause intersymbol interference.
Innovation Solution
A preamble generation method using frequency shift codes and pseudo random binary sequence codes, adjusted according to the operating clock frequency and transmission rate, is employed to improve frame synchronization detection, allowing for low complexity and improved bit error rate performance in human body communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If frequency selective digital transmission scheme is used, then data transmission rate is improved, but spectral efficiency becomes limited
Solution Approach 1:
The patent uses variable length preambles that are dynamically adjusted based on the transmission rate. At higher transmission rates, shorter preambles are used to minimize overhead and maintain spectral efficiency, while at lower rates, longer preambles provide sufficient synchronization. This dynamic adaptation resolves the contradiction between maintaining data transmission rate and optimizing spectral efficiency.
2Object-affected harmful factors
If transmission filter and reception filter are used, then noise removal is improved, but intersymbol interference occurs
Solution Approach 1:
The patent changes the parameter of preamble length to optimize system performance. By using variable length preambles instead of fixed length preambles, the system can adapt to different transmission conditions and rates, achieving both noise removal through filtering and acceptable bit error rate performance without excessive intersymbol interference.
3Device complexity
If fixed length preamble is used, then implementation complexity is reduced, but spectral efficiency is limited
Solution Approach 1:
The patent implements variable length preambles that are dynamically selected based on transmission rate requirements. This dynamic approach achieves maximum spectral efficiency of 1 bps/Hz by optimizing the preamble length for each transmission condition, while maintaining manageable implementation complexity through systematic selection rules.
4Productivity
If variable length preamble is used, then spectral efficiency is improved, but frame synchronization detection complexity increases
Solution Approach 1:
The patent segments the preamble into multiple fields with specific structures (preamble synchronization field, data field, etc.). This segmentation allows the receiver to detect frame synchronization by identifying specific patterns in different segments, reducing detection complexity despite using variable length preambles for optimal spectral efficiency.
Data Source
AI summary
Provided is a method for generating a preamble of a transmission signal for human body communication, the method including using a frequency shift code (FSC) of which a length is adjusted according to an operating clock frequency or a transmission rate and a first pseudo random binary sequence (PRBS) code of p chips where p is a natural number to generate a first preamble unit block of n chips where n is a natural number, using the FSC and a second PRBS code of p′ chips to generate a second preamble unit block of n′ chips, and arraying the first preamble unit block consecutively and repeatedly and disposing the second preamble unit block at a next stage to form the preamble of the transmission signal.