Wireless Terminal Master-Slave Protocol for Battery Conservation
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Solution Overview
Problem
Current IEEE 802.11 wireless local area networks (WLANs) operating in Peer Coordination Function (PCF) mode face challenges in power conservation and data throughput due to constant power consumption by transmitter and receiver devices, as none of the battery-powered peers can reasonably serve as a Point Coordinator, leading to unnecessary power usage and potential retransmissions.
Innovation Solution
A method is introduced that manages peer-to-peer communications in WLANs using a unique frame cycle comprising a beaconing period, broadcast data period, polled data periods, and a contention period, where one terminal acts as a Master and others as Slaves, allowing for power-down periods and alternating Master duties through a round-robin cycle to conserve battery life and distribute power drain evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Point Coordinator (PC) is used to coordinate transmissions in PCF mode, then transmission coordination is improved, but power consumption increases because the PC must remain constantly powered
Solution Approach 1:
The patent implements periodic action by having the Point Coordinator operate in periodic intervals rather than continuously. The PC wakes up at scheduled intervals to coordinate transmissions, polls stations, and manages the contention period, then enters sleep mode. This periodic operation maintains transmission coordination reliability while dramatically reducing average power consumption compared to continuous operation.
Solution Approach 2:
The patent applies dynamics by making the Point Coordinator's operational state changeable between active and sleep modes. The system dynamically adjusts the PC's activity level based on network conditions and timing requirements, allowing it to be fully operational when coordination is needed and completely powered down during idle periods, thus resolving the contradiction between coordination reliability and power consumption.
2Reliability
If the PC remains constantly powered to handle retransmissions, then transmission reliability is improved, but battery life deteriorates
Solution Approach 1:
The patent applies preliminary action by having the Point Coordinator schedule and poll stations in advance during its active periods. The PC proactively manages retransmission opportunities by polling stations before they need to transmit, preparing the network for upcoming transmissions. This preliminary coordination allows the PC to enter sleep mode confidently, knowing that transmission reliability is maintained through advance planning rather than constant monitoring.
Solution Approach 2:
The system implements feedback mechanisms where stations inform the PC of their transmission status and buffer contents during polling periods. The PC uses this feedback to make informed decisions about retransmission opportunities and to schedule its next wake-up period appropriately. This feedback loop ensures transmission reliability is maintained while allowing the PC to optimize its power consumption by sleeping during periods when feedback indicates no transmissions are needed.
3Productivity
If all devices remain powered to listen for potential transmissions, then data throughput is improved, but power consumption increases
Solution Approach 1:
The patent segments the network operation into distinct periods: contention periods where devices may transmit, data periods where coordinated transmissions occur, and sleep periods where devices power down. This temporal segmentation allows devices to remain powered only when necessary for specific network functions, maintaining data throughput during active periods while minimizing power consumption during sleep periods.
Solution Approach 2:
The Point Coordinator performs multiple functions during its brief active periods: it coordinates transmissions, polls stations for data availability, manages retransmissions, and controls the contention period. This multi-functionality allows a single device to handle all coordination tasks intermittently, enabling other devices to power down their receivers during sleep periods without sacrificing overall network throughput.
Data Source
AI summary
A Wireless Local Area Network (WLAN) system in which wireless terminals each operate upon battery power. One of the wireless terminals acts as a Master to coordinate the transmission and receptions of the Slaves so as to reduce the power consumed by all of the devices. The Slaves operate according to a power up and power down sequence to conserve battery power. Further, the terminals may alternate between being Slaves and being the Master to equalize battery consumption of the wireless terminals.