Cellular Wakeup Receiver for LTE-WLAN Aggregation Power Reduction
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Solution Overview
Problem
Current cellular technologies face challenges in reducing power consumption while maintaining low latency, as existing paging mechanisms consume unnecessary power and keep cellular radios in high-energy states due to large cell sizes and non-contention-based scheduling in LTE networks.
Innovation Solution
A Cellular Wake-Up Receiver (C-WuRx) is introduced, which operates as a low-power radio to monitor for wake-up signals within the LTE band, allowing the main cellular modem to remain powered down until needed, using a simple radio waveform and cycling between active and sleep states to minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main cellular modem continuously monitors for downlink data in LTE networks, then data reception reliability is improved, but power consumption increases significantly
Solution Approach 1:
The system segments the monitoring function by introducing a separate wake-up receiver that handles initial signal detection, allowing the main cellular modem to remain in low-power state. The wake-up receiver and main modem operate as independent segments with distinct functions, reducing overall power consumption while maintaining monitoring capability.
Solution Approach 2:
The wake-up receiver acts as an intermediary between the external environment and the main cellular modem. It receives and processes wake-up signals first, then activates the main modem only when necessary, serving as a mediator that protects the main system from unnecessary activation and power consumption.
2Use of energy by moving object
If the main cellular modem enters sleep mode to reduce power consumption, then energy expenditure decreases, but data reception latency increases
Solution Approach 1:
The wake-up receiver performs preliminary monitoring and signal detection before the main modem needs to be activated. By detecting wake-up signals in advance and preparing the system for activation, it reduces the actual latency when data reception is needed, while the main modem remains in low-power state.
Solution Approach 2:
The system uses periodic wake-up signal transmission from the base station to trigger main modem activation. This periodic approach allows the main modem to remain asleep between periods, reducing power consumption, while ensuring timely activation when data is available, balancing latency and energy expenditure.
3Area of stationary object
If LTE networks use large cell sizes for coverage, then service area is improved, but power consumption for signal monitoring increases
Solution Approach 1:
The monitoring function is segmented between the wake-up receiver that handles broad coverage detection and the main modem that handles detailed communication. This segmentation allows large cell coverage to be maintained while reducing the power required for continuous monitoring by the main modem.
Solution Approach 2:
The wake-up receiver creates a simplified copy of the monitoring function, handling basic signal detection and wake-up signal recognition. This copy performs the essential coverage monitoring task with much lower power consumption than the full main modem, enabling large service area coverage without proportional power increase.
Data Source
AI summary
A cellular wakeup receiver (C-WuRx) for reducing power consumption of a wireless wide area network (WWAN) radio of a user equipment (UE) includes receiver circuitry to receive a wakeup signal from a base station in response to the UE performing link aggregation by which downlink communications from the base station are offloaded to a wireless local area network (WLAN). The C-WuRx also includes processing circuitry to configure the receiver circuitry to periodically monitor at least a portion of a WWAN band for the wakeup signal and process the wakeup signal to cause the WWAN radio to resume receiving the downlink communications from the base station.