Paging in Unlicensed Spectrum via Multiple Paging Occasions
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Solution Overview
Problem
In LTE systems operating in unlicensed spectrum, the uncertainty of successful paging message transmission due to Listen-Before-Talk (LBT) failures leads to inefficiencies and increased latency, as existing methods rely on a single Paging Occasion (PO) for paging, which may not guarantee successful delivery.
Innovation Solution
Implementing a set of Paging Occasions (POs) within a Paging Occasion Window (POW) allows for flexible and efficient paging by determining a first and last subframe, enabling the terminal to attempt to acquire paging information in any subframe between them, thereby ensuring successful transmission even if LBT fails during a specific PO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single Paging Occasion (PO) is used for paging in unlicensed spectrum, then the paging procedure follows standard LTE protocol, but the transmission reliability deteriorates due to LBT failures causing uncertainty in successful message delivery
Solution Approach 1:
The single Paging Occasion is segmented into multiple POs within a Paging Occasion Window (POW). The terminal determines a first subframe and a last subframe of a set of POs, and is required to attempt to acquire paging information in any subframe between the first subframe and the last subframe. This segmentation allows the terminal to try multiple POs if LBT fails on the first attempt, thereby improving transmission reliability without requiring complex retransmission protocols.
2Reliability
If multiple Paging Occasions are configured to improve paging reliability, then transmission success rate increases, but the terminal's power consumption increases due to monitoring more POs
Solution Approach 1:
The terminal is required to attempt to acquire paging information in any subframe between the first subframe and the last subframe of the set of POs, but not necessarily monitor all POs. The terminal can stop monitoring after successfully acquiring paging information, or after a certain number of attempts. This partial monitoring approach reduces power consumption compared to monitoring all POs, while still improving reliability compared to monitoring a single PO.
3Loss of time
If the terminal monitors a single PO for paging information, then the procedure is simple and fast, but paging latency increases when LBT fails
Solution Approach 1:
The terminal determines the set of POs (first subframe and last subframe) in advance, before actual paging transmission occurs. This preliminary determination allows the terminal to have a ready list of alternative POs to monitor, so when LBT fails on the first PO, the terminal can immediately proceed to the next PO without complex real-time decision-making, thus reducing latency while maintaining procedural simplicity.
Data Source
AI summary
A method and a terminal for acquiring paging information during a set of one or more paging occasions, one paging occasion corresponding to a subframe. In an embodiment, the method determines a first subframe of the set of one or more paging occasions and determines a last subframe of the set of one or more paging occasions. The terminal is required to attempt to acquire the paging information in any subframe between the first subframe and the last subframe of the set of one or more paging occasions.