C-DRX Wake-Up via UE-Specific Reference Signals
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Solution Overview
Problem
In millimeter wave (mmW) wireless communication systems, the high path loss and beam management complexities lead to increased power consumption in user equipment (UE) due to the need for continuous monitoring of control channels and beam sweeping, especially in connected discontinuous reception (C-DRX) mode.
Innovation Solution
A base station conveys the UE identifier using UE-specific reference signals, which are beam swept to indicate data availability, allowing the UE to decode and respond with a beam recovery signal, optimizing beam management and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE monitors the PDCCH continuously to detect data availability, then the data detection reliability is improved, but the power consumption increases
Solution Approach 1:
The UE operates in DRX mode, periodically switching between active and sleep states. During active state, the UE monitors PDCCH for data availability; during sleep state, the UE shuts down hardware to conserve power. This periodic monitoring approach maintains data detection capability while significantly reducing average power consumption compared to continuous monitoring.
2Reliability
If the base station beam sweeps the PDCCH transmissions to mitigate high path losses, then the signal reliability is improved, but the UE wake time and power consumption increase
Solution Approach 1:
The patent extracts the data availability indication from the PDCCH monitoring process and embeds it in UE-specific reference signals (RS). The base station beam sweeps these RS transmissions to mitigate path loss, and the UE detects data availability by decoding these RS instead of monitoring PDCCH during beam sweeping, thereby reducing wake time while maintaining signal reliability.
Solution Approach 2:
The UE-specific reference signals serve as an intermediary mechanism. Instead of directly monitoring PDCCH during beam sweeping, the UE detects data availability through these intermediary RS that carry the same indication information, allowing for more efficient detection with reduced power consumption and shorter wake time.
3Measurement precision
If the UE attempts to decode the PDCCH multiple times to ensure reliable detection, then the detection accuracy is improved, but the power consumption increases
Solution Approach 1:
The patent uses UE-specific reference signals as a copy or alternative carrier for the data availability indication. Instead of repeatedly decoding PDCCH multiple times, the UE decodes the UE-specific RS which contains the same indication information, achieving reliable detection with fewer decoding attempts and lower power consumption.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. A base station may identify that data is available to be transmitted to a user equipment (UE) that is operating in a discontinuous reception (DRX) mode. The base station may configure a plurality of UE-specific reference signals for transmission to the UE, each UE-specific reference signal indicating a UE identifier and an availability of data for the UE. The UE may receive the UE-specific reference signal, and identify that data is available for the UE from the base station. The UE may then transmit a beam recovery signal to the base station that includes an identifier for the transmit beam used by the UE to transmit the beam recovery signal. The base station may transmit, using a beam sweeping configuration, the plurality of UE-specific reference signals.