LPWA Packet Header Overhead Reduction via Shared FEC Symbol Counts
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Solution Overview
Problem
Current Low Power Wide Area (LPWA) communication technologies, such as LoRa, face limitations in payload size per packet, leading to high overhead due to header information, restricted downlink communication, and infrequent data transmission, especially when applying Application Layer Forward Error Correction (AL-FEC), which hampers efficient data transmission in IoT devices with limited power supply.
Innovation Solution
The proposed solution involves a method to suppress header information dedicated for AL-FEC by sharing the number of information word symbols and parity symbols between transmission and reception apparatuses, allowing for efficient packet transmission and decoding without the need for additional header information, using a configuration where each packet includes a flag indicating whether it contains an information word symbol or a parity symbol, and incorporating a cyclic redundancy check (CRC) for error detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AL-FEC is applied to ensure reliable data transmission in LPWA networks, then error correction capability is improved, but header information overhead increases
Solution Approach 1:
The transmitter pre-calculates and transmits the number of information word symbols and parity symbols before actual data transmission. This preliminary action allows the receiver to correctly interpret the packet structure without requiring additional header information, thereby reducing overhead while maintaining AL-FEC error correction capabilities
Solution Approach 2:
The system uses its own transmission parameters (number of information word symbols and parity symbols) as the notification mechanism. By making these parameters publicly known or pre-shared between transmitter and receiver, the system eliminates the need for separate header information to describe the packet structure, achieving self-service without additional overhead
2Use of energy by moving object
If packet size is increased to reduce transmission frequency, then power consumption is reduced, but payload size limitation per packet restricts this approach
Solution Approach 1:
The patent segments the total data into multiple packets, each containing a specific number of information word symbols and parity symbols. This segmentation allows flexible configuration of packet sizes to match LPWA payload limitations while maintaining efficient error correction. The total data can be transmitted across multiple packets without requiring each individual packet to carry the entire payload
Solution Approach 2:
The system dynamically adjusts the number of information word symbols and parity symbols in each packet based on channel conditions and requirements. By changing these parameters, the system can optimize the balance between transmission efficiency and error correction capability, working within LPWA payload size constraints while minimizing power consumption through reduced transmission frequency
3Device complexity
If downlink communication is restricted to reduce network complexity, then device complexity is reduced, but communication flexibility is limited
Solution Approach 1:
The patent implements a universal notification mechanism that works for both uplink and downlink communications. The transmitter (whether in uplink or downlink mode) publicly announces or pre-shares the number of information word symbols and parity symbols, and the receiver uses this information to correctly decode packets. This universal approach maintains communication flexibility across different directions while avoiding the need for complex direction-specific protocols
Data Source
AI summary
A reception apparatus includes a receiver and circuitry. The receiver receives, from a transmission apparatus, a plurality of packets that include code word symbols which include an information word symbol and a parity symbol. The information word symbol is generated from transmission information. The parity symbol is calculated from the information word symbols. The circuitry decodes the code word symbols that are included in the plurality of packets. The number of first packets and the number of second packets among the plurality of packets are shared between the transmission apparatus and the reception apparatus. Each of the first packets includes the information word symbol. Each of the second packets includes the parity symbol.