Scheduled Device-Specific Synchronization Signals for Low-Power Paging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mobile devices in wireless networks face inefficiencies in power consumption and synchronization due to long sleep durations, leading to excessive battery drain and clock drift, especially in Machine-Type Communications (MTC) devices operating in deep coverage areas with low signal strength, where the time required for resynchronization and decoding control channels is significant.
Innovation Solution
Transmission of a device-specific synchronization signal (DS-SS) within a data channel before a paging time window allows mobile devices to synchronize and determine the presence of a page message without decoding the downlink control channel, reducing unnecessary resynchronization and control channel decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the mobile device increases the sleep duration to save power, then battery consumption is reduced, but the clock drifts away from nominal timing value requiring resynchronization
Solution Approach 1:
The base station transmits the device-specific synchronization signal (DS-SS) in advance before the paging time window, allowing the mobile device to perform resynchronization before checking for page messages. This preliminary transmission of timing information enables the device to wake up with accurate synchronization without requiring longer wake periods for resynchronization procedures.
Solution Approach 2:
The invention extracts the essential timing synchronization function from the conventional synchronization procedure by creating a dedicated DS-SS signal that carries only the critical timing information needed for resynchronization. This extracted timing signal is transmitted separately and can be quickly acquired by the mobile device without requiring full control channel decoding.
2Reliability
If the mobile device reduces sleep duration to maintain timing accuracy, then clock drift is reduced, but the time for resynchronization exceeds the time to receive and decode the page message
Solution Approach 1:
The DS-SS is transmitted in advance of the paging time window, allowing the mobile device to complete resynchronization before the page message transmission begins. This eliminates the need to perform resynchronization during the page reception window, ensuring that timing accuracy is restored without encroaching on the page message decoding time.
Solution Approach 2:
The synchronization and paging procedures are segmented into separate time slots: the DS-SS transmission occurs in a dedicated synchronization opportunity before the paging time window. This segmentation allows the mobile device to efficiently perform resynchronization in one segment and page message reception in another, without the procedures interfering with each other.
3Reliability
If the mobile device decodes the downlink control channel to obtain signal transmission information, then accurate timing synchronization is achieved, but power consumption increases
Solution Approach 1:
The invention extracts the timing synchronization information from the control channel and places it in a dedicated DS-SS signal. The mobile device can then acquire timing information by detecting the DS-SS without needing to decode the full downlink control channel, significantly reducing the processing power and energy required for synchronization.
Solution Approach 2:
The DS-SS serves as a lightweight, simplified synchronization mechanism that provides the essential timing information without the overhead of full control channel decoding. It is a 'cheap' solution in terms of processing requirements, allowing the mobile device to quickly acquire timing and return to sleep state without expending significant energy on complex decoding operations.
Data Source
AI summary
A device-specific synchronization signal (DS-SS) is transmitted by a base station within a data channel transmission to a mobile device before a paging time window for the mobile device. After a sleep state, the mobile device attempts to acquire the DS-SS without decoding a downlink control channel to obtain signal transmission information related to transmission of the page message from a base station. In addition to providing timing information for resynchronization, the DS-SS indicates the existence of a page message for the mobile device within the data channel. The mobile device returns to the sleep state in response to not detecting a DS-SS that indicates a page message. Prior to entering a sleep state, the mobile device receives transmission format information indicative of a transmission format of the DS-SS.