Wakeup Receiver Timing Synchronization with LP-SS Cover Coding
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Solution Overview
Problem
Wireless communications systems face challenges in maintaining timing synchronization due to uncertainty in beam and repetition configurations of low-power synchronization signals, leading to potential failures in waking up secondary receivers.
Innovation Solution
Techniques such as cover coding LP-SS transmissions, increasing the duration of monitoring windows, and applying fixed offsets between LP-SSs and WUSs are employed to mitigate ambiguity and ensure accurate timing synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LP-SS transmissions are sent without cover coding, then transmission simplicity is maintained, but timing synchronization reliability deteriorates due to beam and repetition configuration ambiguity
Solution Approach 1:
A cover code is introduced as an intermediary element between the LP-SS transmission and the receiver. This cover code explicitly indicates the beam index and repetition number, serving as a mediator that resolves the ambiguity between multiple transmission configurations. The cover code allows the receiver to correctly identify which beam and repetition occasion the LP-SS corresponds to, thereby ensuring reliable timing synchronization without requiring complex receiver processing of multiple hypotheses.
2Reliability
If monitoring window duration is increased, then timing synchronization reliability is improved, but time resource consumption increases
Solution Approach 1:
The cover code is provided in advance with the LP-SS transmission, containing all necessary information about the beam index and repetition number. This preliminary provision of timing information allows the receiver to immediately and accurately determine the monitoring window position without needing to extend the monitoring window duration to account for synchronization uncertainty. The preliminary action of providing cover coding information eliminates the need for extended monitoring periods.
3Reliability
If multiple LP-SS repetitions are transmitted across different slots, then coverage reliability is improved, but timing ambiguity increases without cover coding
Solution Approach 1:
The cover code acts as an intermediary that carries timing identification information across multiple LP-SS repetitions. Each LP-SS transmission includes or is associated with a cover code that explicitly indicates which repetition occasion and beam it corresponds to. This mediator element prevents information loss about timing identity even when multiple repetitions are transmitted across different slots, allowing the receiver to correctly associate each LP-SS with its specific transmission occasion.
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for receiving a low-power synchronization signal (LP-SS) in one or more slots using a first receiver: and monitoring, using the first receiver, for a wakeup signal (WUS) associated with a second receiver in a monitoring window based at least in part on the one or more slots in which the LP-SS is received. Certain aspects of the present disclosure provide techniques for outputting an LP-SS in one or more slots; and outputting a WUS in a monitoring window based at least in part on the one or more slots in which the LP-SS is outputted.