Wireless Receiver Clock Rate Reduction for Idle Listening Energy Savings
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Solution Overview
Problem
WiFi devices experience high energy consumption due to idle listening, which accounts for a significant portion of their power usage, despite existing power-saving modes, as the radio must continuously perform carrier sensing and packet detection, leading to inefficiencies.
Innovation Solution
Reducing the clock rate of wireless communication devices during idle listening periods and using a customized preamble for packet detection, allowing the device to operate at a lower clock rate unless a packet intended for the device is detected, thereby minimizing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radio continuously performs idle listening to detect packets and assess clear channel, then packet detection reliability is improved, but power consumption increases significantly
Solution Approach 1:
The system transitions from continuous idle listening to periodic wake-up listening. The client device wakes up at scheduled intervals to check for buffered packets at the access point, then returns to sleep mode. This periodic operation dramatically reduces power consumption while maintaining reliable packet detection through the buffered packet mechanism at the access point.
Solution Approach 2:
The access point acts as an intermediary by buffering downlink packets for clients during their sleep periods. Instead of requiring the client to continuously listen for packets, the access point stores incoming packets and delivers them when the client wakes up, eliminating the need for continuous client-side packet detection while maintaining reliability.
2Use of energy by moving object
If power-saving mode is enabled to reduce idle listening time, then energy consumption decreases, but network-level latency increases due to packet buffering
Solution Approach 1:
The system performs preliminary actions by having the access point buffer packets in advance during the client's sleep period. Packets are queued and ready for immediate delivery when the client wakes up, eliminating the need for the client to wait for packet arrival during sleep intervals. This preliminary buffering action resolves the latency issue while maintaining power-saving benefits.
3Duration of action of moving object
If sleep scheduling is implemented to wake up only when packets are expected, then idle listening time is reduced, but carrier sensing and contention opportunities are lost
Solution Approach 1:
The system segments the listening function into two parts: the access point continuously performs carrier sensing and packet reception, while the client device performs periodic wake-up checks for buffered packets. This segmentation allows the client to reduce idle listening time significantly while the access point maintains continuous channel awareness, preserving carrier sensing efficiency at the network level.
Data Source
AI summary
Techniques are provided for reducing power consumption in wireless communication devices. During an idle listening period, the clock rate of the receiver in the device is reduced. Data packets received by the receiver are then sampled at the reduced clock rate. A determination is made as to whether the data packet is intended for the device. The clock rate is restored to the full clock rate when the data packet is intended for the device. On the other hand, the receiver continues to operate at the reduced clock rate when the data packet is not intended for the device.