Repeated SRS Transmission for MTC Uplink Channel Estimation
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Solution Overview
Problem
Wireless access systems face challenges in reliably estimating the uplink channel for Machine Type Communication (MTC) user equipment, especially in poor conditions, due to limitations in existing SRS transmission methods.
Innovation Solution
A method and apparatus for repeated SRS transmission in MTC environments, involving specific SRS configuration and transmission techniques to improve channel estimation, including consistent SRS sequences and subband allocation, to enhance channel estimation reliability for MTC user equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SRS transmission methods are used for MTC user equipment, then the system maintains standard operation, but the uplink channel estimation reliability deteriorates in poor conditions
Solution Approach 1:
The patent implements repeated SRS transmissions at configured intervals to continuously update channel estimates. The base station configures the UE to transmit SRS repeatedly in accordance with a repetition factor, allowing the base station to accumulate multiple channel observations over time and improve estimation reliability in poor channel conditions through temporal averaging and selection of the best estimates.
2Reliability
If repeated SRS transmission is implemented for MTC, then channel estimation reliability improves, but the transmission overhead and resource consumption increase
Solution Approach 1:
The patent applies partial action by transmitting SRS repeatedly only when needed for MTC UEs in poor channel conditions, rather than continuously for all UEs. The base station configures a repetition factor that determines the number of repetitions, allowing flexible resource allocation that provides enhanced reliability only where necessary while minimizing overall system overhead.
3Adaptability or versatility
If SRS sequences are changed frequently, then interference diversity improves, but channel estimation consistency deteriorates
Solution Approach 1:
The patent employs periodic SRS transmissions with consistent sequences within each repetition period, allowing the UE to maintain stable channel estimates across multiple transmissions. The base station configures the repetition factor and sequence parameters to ensure that the same or related SRS sequences are transmitted periodically, providing consistent channel state information while still benefiting from temporal diversity through multiple observation opportunities.
Data Source
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AI summary
The present invention provides methods for transmitting an SRS in a wireless access system supporting machine type communication and apparatuses for supporting the same. A method for transmitting a sounding reference signal (SRS) by a terminal in a wireless access system supporting machine type communication (MTC) according to an embodiment of the present invention may comprise the steps of: receiving an SRS transmission parameter configured for repeated transmission of an SRS from a base station; and repeatedly transmitting an SRS during a predetermined SRS repeated transmission interval according to the SRS transmission parameter.