Constant Amplitude Encoding for CDM Sensor Networks
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Solution Overview
Problem
Existing code division multiplexing communication systems face challenges in optimizing the physical layer of ubiquitous sensor networks for efficient error restoration and retransmission, particularly in low power outdoor wide area communication environments, where power consumption and interference resilience are critical.
Innovation Solution
A constant amplitude encoding apparatus and method that includes an input frame generation module, 1/N conversion module, interleaving module, 9/16 turbo product code module, and constant amplitude multiplexing module, which divides data into blocks, adds cyclic redundancy check bits, performs block interleaving, and adds additional bits to achieve 9/16 code rate matching and enhance reliability against errors and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional constant amplitude encoding is used in CDM systems, then binary orthogonal code transmission is achieved with constant amplitude, but transmission efficiency is limited and interference resilience is insufficient
Solution Approach 1:
The patent segments the transmission signal into multiple orthogonal codes (at least three codes including first, second, and third orthogonal codes) with different amplitude characteristics. This segmentation allows the system to distribute information across multiple code channels, improving both transmission efficiency through parallel transmission and reliability through diversity against interference affecting any single code.
Solution Approach 2:
The patent changes the amplitude parameters of different orthogonal codes, specifically setting the first and second orthogonal codes with amplitude A and the third orthogonal code with amplitude B where A≠B. This parameter variation enables the system to achieve constant envelope transmission while maintaining high transmission efficiency through optimized code rate matching (9/16 code rate) and improved interference resilience through amplitude diversity.
2Productivity
If 9/16 code rate matching is implemented, then transmission efficiency is improved, but system complexity increases
Solution Approach 1:
The patent performs preliminary action by pre-defining specific mapping relationships between data bits and orthogonal codes before transmission. The encoding apparatus is configured with predetermined code assignments where specific bit patterns map to specific orthogonal codes with known amplitude characteristics. This preliminary configuration simplifies the real-time encoding process while achieving the target 9/16 code rate matching efficiency.
Solution Approach 2:
The patent creates a universal encoding framework that can handle multiple data rates and transmission conditions through a single apparatus configuration. The same encoding structure with multiple orthogonal codes and amplitude variations can adapt to different code rate requirements (including 9/16) without requiring separate specialized hardware for each rate, thus reducing overall system complexity while maintaining high efficiency.
3Reliability
If multiple orthogonal codes with different amplitudes are used, then transmission efficiency and reliability are enhanced, but signal processing complexity increases
Solution Approach 1:
The patent applies local quality by assigning different amplitude characteristics (A or B) to different orthogonal codes based on their specific function and error protection requirements. Certain codes may use amplitude A for robust transmission while others use amplitude B for higher data rate, with the receiver configured to interpret these local amplitude variations according to predetermined rules. This localized optimization enhances error restoration reliability without requiring complex global signal processing.
Data Source
AI summary
A method and apparatus for encoding a constant amplitude that is applied to a code division multiplexing communication system are provided. By dividing a data bit into a block unit, the receiving side can easily determine an error, and by reducing power consumption in outdoor wide area communication using a bit string of a small length in a basic unit of an input frame, efficiency can be improved, and thus a physical layer of a ubiquitous sensor network can be optimized.