BeiDou User ID Compression for Lower Satellite Frame Header Overhead
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Solution Overview
Problem
The BeiDou short message communication system faces high frame header overheads due to conventional Binary-Coded Decimal (BCD) encoding of user IDs, which limits data transmission efficiency in satellite communication.
Innovation Solution
A data compression method that encodes user IDs into binary data by compressing national destination codes and subscriber numbers, reducing the data length and minimizing frame header overheads through techniques like mapping and offset subtraction, thereby optimizing user ID representation in frame headers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If BCD encoding is used for user ID, then the user ID can be clearly represented, but the frame header overhead increases
Solution Approach 1:
The patent changes the encoding parameter from BCD (4 bits per decimal digit) to binary encoding (variable bits based on value). By compressing the NDC to 7 bits and SN to 10 bits, the total user ID field is reduced from 44 bits to 34 bits, directly reducing frame header overhead while maintaining unique identification capability.
Solution Approach 2:
The user ID is segmented into two independent parts: NDC (national destination code) and SN (subscriber number). Each part is encoded separately with optimized bit allocation (7 bits for NDC, 10 bits for SN), allowing flexible representation and reducing total overhead compared to treating the entire user ID as a single BCD-encoded value.
2Ease of manufacture
If conventional BCD encoding is used, then the encoding process is simple, but data transmission efficiency is reduced
Solution Approach 1:
The patent changes from fixed BCD encoding to variable-length binary encoding. By allocating 7 bits for NDC (supporting up to 128 values) and 10 bits for SN (supporting up to 1024 values), the system achieves more efficient data representation that reduces transmission overhead by 10 bits per user ID, significantly improving data transmission efficiency.
Data Source
AI summary
In accordance with an embodiment, a method includes: encoding, by a first terminal at a satellite link control (SLC) layer, a first user identification (ID) of the first terminal into binary first data, wherein the first user ID comprises second data and third data, the binary first data includes binary fourth data and binary fifth data, the binary fourth data is obtained by encoding sixth data, the sixth data is obtained by compressing the second data, a data length of the sixth data is less than that of the second data, and the binary fifth data is obtained by encoding the third data; filling, by the first terminal at the SLC layer, the binary first data in a user ID field in frame header information of a first user frame; and sending, by the first terminal, the first user frame to a satellite network device.