Adaptive Reference Signal Transmission for MTC Collision Reduction
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Solution Overview
Problem
In Machine Type Communication (MTC) systems, the limited patterns of uplink reference signals lead to collisions among user terminals, causing interference and reducing system performance, and existing solutions to extend these patterns result in additional signaling overhead and resource waste.
Innovation Solution
A method where user terminals determine whether to transmit an additional reference signal based on channel conditions, such as signal receiving power and timing advance, to adaptively extend the reference signal patterns, reducing collisions without additional signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the base station extends the patterns of uplink reference signals to reduce collisions, then the reference signal collision probability is reduced, but signaling overhead increases
Solution Approach 1:
The user terminal dynamically determines whether to transmit an additional reference signal based on channel conditions (RSRP thresholds, timing advance values). This dynamic adaptation allows the system to extend reference signal patterns only when necessary, reducing collisions while avoiding unnecessary signaling overhead in good channel conditions.
Solution Approach 2:
The user terminal autonomously decides whether to transmit the additional reference signal by evaluating its own channel conditions against predetermined thresholds. This self-service mechanism eliminates the need for the base station to explicitly signal which pattern extension method to use, thereby reducing signaling overhead while still achieving collision reduction.
2Productivity
If multiple user terminals transmit uplink reference signals simultaneously using limited patterns, then grant-free uplink transmission is enabled, but reference signal collisions occur causing interference
Solution Approach 1:
The system changes the parameter of reference signal patterns by introducing an additional reference signal with a different pattern (e.g., different orthogonal cover code or resource element position). User terminals that detect poor channel conditions or high collision risk can switch to this alternative pattern, thereby reducing collisions while maintaining grant-free uplink transmission efficiency.
3Measurement precision
If user terminals transmit additional reference signals based on channel conditions, then channel estimation accuracy is improved, but transmission resources increase
Solution Approach 1:
Instead of all user terminals transmitting additional reference signals, only those experiencing poor channel conditions (below RSRP threshold or with large timing advance values) transmit the additional signal. This partial action approach improves channel estimation accuracy for affected terminals while minimizing the overall consumption of transmission resources.
Data Source
AI summary
Provided are a method for transmitting signals and corresponding terminals, and base stations, where the method for transmitting signals is performed by a terminal in a communication system. The method includes determining, whether to transmit an additional reference signal to a base station in the communication system according to information on channel conditions of the terminal; transmitting a main reference signal to the base station, where the main reference signal is used for channel estimation between the terminal and the base station; and when determining to transmit an additional reference signal to the base station, transmitting an additional reference signal to the base station according to configuration information of the additional reference signal.