Adaptive Duty Cycling for Wireless MAC Energy Efficiency
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Solution Overview
Problem
Existing duty-cycled wireless data networks face inefficiencies in energy consumption, reliability, and responsiveness due to fixed wake-up cycles and lack of adaptive mechanisms for heterogeneous networks and stringent timing requirements.
Innovation Solution
Implementing a transmission scheme that sends a train of packets with acknowledgement mechanisms like Stop-and-Wait ARQ, Selective Repeat, and dual-mode network operation to handle delay-sensitive and delay-insensitive traffic, along with two-level sleeping duty cycling for heterogeneous networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a fixed duty cycle is used for all nodes, then energy efficiency is improved through synchronized sleep-wake cycles, but responsiveness deteriorates for delay-sensitive applications with stringent timing requirements
Solution Approach 1:
The patent implements dynamic duty cycling where nodes can adjust their wake-up intervals based on application requirements. The system supports both fixed and adaptive duty cycles, allowing nodes to switch between different wake-up patterns to meet varying responsiveness needs while maintaining energy efficiency.
Solution Approach 2:
The patent allows different nodes to have different duty cycle configurations based on their specific requirements. Heterogeneous duty cycling is enabled where critical nodes with stringent timing requirements can use shorter wake-up intervals while non-critical nodes use longer intervals, optimizing both energy efficiency and responsiveness at the local level.
2Productivity
If multiple packets are transmitted during each wake-up interval, then productivity is improved, but reliability deteriorates due to packet loss in inherently unreliable wireless links
Solution Approach 1:
The patent implements feedback mechanisms including acknowledgments and retransmission requests. When packets are transmitted in batches, the receiver sends acknowledgments for successfully received packets, and the transmitter uses this feedback to retransmit only the lost packets, thereby maintaining high reliability while achieving high productivity through batch transmission.
Solution Approach 2:
The patent employs preliminary actions such as transmitting packets before the wake-up interval ends and using predictive scheduling to anticipate packet arrival patterns. This allows the system to prepare for potential packet losses by initiating retransmission sequences in advance, maintaining reliability while maximizing throughput.
3Reliability
If a long preamble is used to guarantee receiver wake-up (as in BMAC), then reliability is improved, but energy efficiency deteriorates due to increased overhead for each packet transmission
Solution Approach 1:
The patent merges multiple packets into a single transmission burst during each wake-up interval. Instead of sending one packet per wake-up with a long preamble each time, the system transmits multiple packets in sequence during one wake-up event, sharing the preamble overhead across all packets in the batch, thereby reducing energy consumption per packet while maintaining reliable delivery.
Solution Approach 2:
The patent uses preliminary synchronization and wake-up signaling that allows the receiver to stay awake longer during the wake-up interval, preparing to receive multiple packets without needing repeated long preambles. This preliminary action enables more efficient subsequent packet transmissions within the same wake-up cycle.
4Use of energy by moving object
If duty cycling is implemented to reduce idle listening, then energy efficiency is improved, but complexity increases due to synchronization requirements and multiple MAC protocols needed for different applications
Solution Approach 1:
The patent creates a universal MAC protocol framework that can handle both delay-sensitive and delay-insensitive applications within the same duty-cycling mechanism. The system provides multiple service types and QoS parameters that allow a single protocol to serve diverse applications, eliminating the need for separate MAC protocols while maintaining energy efficiency through duty cycling.
Data Source
AI summary
A system and method for medium access control in a wireless communication network including the use of packets having a header and plural data portions, acknowledgement request features, corrupt packet identification, and adaptive duty cycling.