MTC Device Downlink Synchronization via Dedicated Signals
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Solution Overview
Problem
Machine type communication (MTC) devices operating in sleep mode for power saving often lose downlink synchronization with the base station, leading to increased overhead and power consumption when re-synchronizing upon data transmission or reception.
Innovation Solution
A method for MTC devices to receive an MTC-dedicated synchronization signal from the base station on a sub-band within the entire system bandwidth before attempting to receive a paging message, allowing for quick re-synchronization upon waking from sleep mode, using a simple-type synchronization signal like a preamble, and potentially utilizing existing synchronization signals for faster synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If MTC devices operate in sleep mode for power saving, then power consumption is reduced, but downlink synchronization is lost
Solution Approach 1:
The base station transmits MTC-dedicated synchronization signals in advance before the MTC device needs to wake up for paging reception. This preliminary transmission of synchronization information allows the device to quickly re-synchronize without needing to perform lengthy synchronization procedures after waking from sleep mode, thus resolving the contradiction between power saving and maintaining synchronization reliability
2Reliability
If MTC devices perform full synchronization procedure upon waking, then synchronization reliability is improved, but time and power consumption increase
Solution Approach 1:
The patent extracts and separates the essential synchronization function from the complete synchronization procedure. By transmitting MTC-dedicated synchronization signals that contain only the critical timing and frequency information needed for quick re-synchronization, the system enables MTC devices to acquire synchronization without performing the full synchronization procedure, thus reducing both time and power consumption while maintaining sufficient synchronization reliability for paging reception
3Device complexity
If MTC devices use existing synchronization signals, then device complexity is reduced, but synchronization speed is insufficient
Solution Approach 1:
The patent applies local quality by creating MTC-dedicated synchronization signals with specific properties optimized for MTC devices' needs. These signals are transmitted in specific subframes (e.g., subframe 4 and subframe 9) and contain localized synchronization information tailored for MTC devices operating in sleep mode, enabling faster synchronization speed while keeping device complexity low since the signals use the same basic structure as existing synchronization signals
Data Source
AI summary
The present specification provides a method for obtaining downlink synchronization in a machine type communication (MTC) apparatus. The MTC apparatus may comprise the steps of: receiving an MTC-dedicated synchronization signal from a base station on the subframe before a subframe which attempts to receive a paging message; obtaining a downlink synchronization of the base station through the synchronization signal; and after obtaining the downlink synchronization, attempting to receive the paging message. Here, the MTC-dedicated synchronization signal may be received on the same sub-band as a sub-band on which the paging message is received, from among the entire system band of the base station.