Scheduled Device-Specific Synchronization Before Paging Windows
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Solution Overview
Problem
Mobile devices, particularly MTC devices, face significant power consumption and synchronization challenges due to long sleep durations, clock drift, and low signal strength, leading to inefficient resynchronization processes that consume excessive energy and reduce battery life.
Innovation Solution
Transmission of a device-specific synchronization signal (DS-SS) over a physical downlink data channel before a paging time window, allowing mobile devices to synchronize without decoding control channels, thereby reducing unnecessary power consumption and synchronization time.
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 drift increases requiring more time for resynchronization
Solution Approach 1:
The network transmits the device-specific synchronization signal (DS-SS) in advance before the paging time window, so that when the mobile device wakes up from sleep, the synchronization signal is already available. This preliminary transmission of synchronization information eliminates the need for the device to perform time-consuming resynchronization procedures after waking up, thus allowing the device to maintain longer sleep durations while minimizing resynchronization time overhead.
2Measurement precision
If the mobile device performs full synchronization and decodes control channels upon waking, then timing accuracy is maintained, but power consumption increases
Solution Approach 1:
The invention extracts only the essential synchronization information from the full control channel decoding process. The device-specific synchronization signal (DS-SS) contains only the timing synchronization data needed by the mobile device, separated from the complete control channel information. This allows the device to acquire timing accuracy without performing the energy-intensive full control channel decoding, thus reducing power consumption while maintaining timing precision.
Solution Approach 2:
The network automatically provides the device-specific synchronization signal (DS-SS) tailored to each mobile device's specific needs and scheduling information. The synchronization signal is customized for each device based on its DRX cycle and paging schedule, eliminating the need for the device to perform generic full synchronization procedures. This self-service approach ensures each device receives precisely the synchronization information it needs, minimizing energy expenditure while maintaining accurate timing.
3Reliability
If the mobile device wakes up frequently to check for pages, then message reception reliability is improved, but the benefit of sleep state is reduced
Solution Approach 1:
The network transmits the device-specific synchronization signal (DS-SS) in advance before the paging time window, enabling the mobile device to perform rapid synchronization upon waking. This preliminary preparation of synchronization information allows the device to wake up frequently with confidence that synchronization will be quick and efficient, thus maintaining message reception reliability without significantly increasing power consumption from prolonged wake periods.
Data Source
AI summary
A device-specific synchronization signal (DS-SS) is transmitted by a base station within a data channel transmission prior to a page timing window (PTW) of designated for at least one mobile device. The DS-SS includes a plurality of sequence instances where each sequence instance is based on a single root sequence. Prior to entering a sleep state, the mobile device receives transmission information indicative of the DS-SS transmission including at least one of a timing and format of the DS-SS transmission. After a sleep state, a mobile device acquires the DS-SS.