Pilot Arrangement Method for SIR Estimation in LTE
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Solution Overview
Problem
In LTE mobile communication systems, large pilot channel intervals lead to deteriorated signal-to-interference ratio (SIR) estimation accuracy, affecting scheduling and throughput due to frequency selectivity and delay dispersion.
Innovation Solution
A pilot arrangement method that divides the frequency band into multiple bands with time division multiplexing, inserting known pilot symbols at a smaller interval than the standard reference interval, based on signal-to-interference ratio measurement information, to enhance SIR estimation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pilot channel insertion interval is increased to reduce pilot overhead, then the number of common pilots in resource blocks decreases, but the SIR estimation accuracy deteriorates due to frequency selectivity and delay dispersion
Solution Approach 1:
The frequency band is segmented into multiple bands, and pilot channels are arranged with different intervals in different frequency bands. Specifically, in bands affected by frequency selectivity and delay dispersion, pilot channels are arranged with smaller intervals to maintain accurate SIR estimation, while in other bands, larger intervals reduce overhead.
Solution Approach 2:
Different pilot channel arrangement strategies are applied to different frequency bands based on local channel characteristics. Bands with high frequency selectivity and delay dispersion receive denser pilot arrangements for accurate measurement, while bands with better characteristics use sparser arrangements to reduce overhead.
2Productivity
If the pilot channel interval is large, then resource efficiency improves, but the interference power estimation accuracy deteriorates leading to poor CQI accuracy and reduced throughput
Solution Approach 1:
The frequency band is divided into multiple segments with different pilot arrangement densities. This segmentation allows the system to optimize resource efficiency in bands where frequency selectivity and delay dispersion are not severe, while maintaining accurate interference power estimation in bands where these effects are significant.
Solution Approach 2:
The pilot channel arrangement interval is changed as a parameter based on frequency band characteristics. By adjusting this parameter dynamically across different frequency bands, the system achieves optimal balance between resource efficiency and measurement accuracy for each band.
Data Source
AI summary
A pilot arrangement method in a mobile radio communication system by which, in order to avoid a problem that poor CQI accuracy affects the scheduling of channel arrangement to cause the throughput to be deteriorated, a working frequency band is divided into a plurality of predetermined bands and time division multiplexing is performed. A known pilot symbol is inserted into the predetermined frequency bands at predetermined reference intervals. Furthermore, the known pilot symbol is inserted into at least one of the predetermined frequency bands at smaller intervals than the predetermined reference intervals and arranged.