MTC UE Synchronization Signal Request via Random Access Preamble
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Solution Overview
Problem
In wireless communication systems, particularly in 3GPP LTE, machine type communication (MTC) user equipment (UE) faces challenges in reducing power consumption while maintaining coverage, especially in cost-effective and low-complexity devices used in coverage-limited areas, without degrading spectral efficiency or affecting legacy UEs.
Innovation Solution
A method and apparatus where MTC UE initiates a request for synchronization signals by transmitting a random access preamble, receives the synchronization signals, and performs synchronization, thereby minimizing power consumption and optimizing battery life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If MTC UEs continuously monitor for synchronization signals to maintain coverage in coverage-limited areas, then coverage reliability is improved, but power consumption increases
Solution Approach 1:
The network configures MTC UEs with discontinuous reception (DRX) cycles, where UEs wake up periodically to monitor for synchronization signals and system information, then return to sleep mode. This periodic monitoring approach maintains coverage reliability by ensuring UEs can detect synchronization signals when needed, while significantly reducing power consumption compared to continuous monitoring.
2Area of stationary object
If MTC UEs use coverage enhancement techniques to extend coverage in basement areas, then coverage area is improved, but spectral efficiency deteriorates
Solution Approach 1:
The system applies coverage enhancement techniques selectively only to MTC UEs in coverage-limited areas (such as basement installations), while legacy UEs in normal coverage areas continue to use standard procedures. The network identifies MTC UEs through specific random access preambles and applies enhanced synchronization signal transmission (repeated transmissions, higher power) only to these devices, thereby extending coverage area without causing spectral efficiency degradation across the entire network.
3Measurement precision
If MTC UEs transmit random access preambles frequently to request synchronization signals, then synchronization accuracy is improved, but power consumption increases
Solution Approach 1:
The network pre-configures MTC UEs with synchronization signal parameters and system information through dedicated RRC signaling before the UEs need to perform random access. This preliminary provision of synchronization information reduces the need for frequent random access preamble transmissions, thereby maintaining synchronization accuracy while reducing power consumption associated with frequent transmission attempts.
Data Source
AI summary
A method and apparatus for requesting a synchronization signal in a wireless communication system is provided. A machine type communication user equipment (MTC UE) transmits a random access preamble for requesting the synchronization signal to a network, receives the synchronization signal from the network, and performs synchronization by using the received synchronization signal.