Chirp Spread Spectrum Wireless Control Method
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Solution Overview
Problem
Low throughput wireless networks face challenges in controlling endpoints with limited power and data rate, requiring efficient network adaptation mechanisms that minimize downlink transmission and listening time, while handling redundant base stations and interference in unlicensed bands.
Innovation Solution
A wireless communication method using chirp spread spectrum with uplink and downlink messages modulated in opposite frequency directions, allowing for network parameter adaptation, such as transmission speed and data rate, with a lower duty cycle and ability to handle multiple base stations without coordination, using cyclic shift modulated chirp spread spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If normal data packets are used for control in low throughput networks, then reliable transmission of control information is achieved, but bandwidth consumption increases significantly
Solution Approach 1:
The patent extracts control information from normal data packets and embeds it within the chirp sequence structure itself. The control messages are transmitted using the same physical layer resources (chirp sequences) as data, but with distinct modulation patterns, thereby eliminating the need for separate control packets and reducing bandwidth consumption.
Solution Approach 2:
The chirp sequence structure is designed to serve multiple functions simultaneously: data transmission, control signaling, and acknowledgment. By encoding control information within the same chirp sequences used for data, the system achieves multi-functionality without requiring additional dedicated control channels or packets.
2Reliability
If endpoints listen continuously for network control messages, then control reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic listening intervals for endpoints rather than continuous monitoring. Endpoints wake up at predetermined intervals to check for control messages from the base station, then return to low-power sleep mode. This periodic action maintains control reliability while significantly reducing power consumption compared to continuous listening.
3Productivity
If link rate adaptation is performed using statistics-based mechanisms, then transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The patent implements a self-service adaptation mechanism where the base station autonomously determines optimal transmission parameters based on simple signal quality metrics. The base station adjusts the chirp sequence modulation and coding without requiring complex endpoint-based statistics collection or feedback mechanisms, thereby achieving transmission efficiency improvement with minimal device complexity.
4Reliability
If transmit duty cycle is increased at base station level, then control reliability is improved, but interference to other transmissions increases
Solution Approach 1:
The base station transmits control messages using periodic bursts rather than continuous transmission. Control information is sent at specific intervals aligned with endpoint listening windows, allowing the base station to maintain control reliability while minimizing transmit duty cycle and reducing interference to other transmissions during idle periods.
Data Source
Figure 1~2
AI summary
A method of control of a plurality of end-points by a plurality of base stations, comprising issuing a frame by at least one end-point, sending the frame to at least one base station and sending a response frame from the base station to the end-point upon receiving the frame. The response frame comprises a plurality of downchirps, containing at least two sequences. The sequences comprise a positive acknowledge as well as a control sequence such as an increase rate or decrease rate control sequence.