Interference Power Measurement in TDD CDMA Systems
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Solution Overview
Problem
Existing methods for measuring interference signal power in 3GPP TDD systems are inadequate for user terminals in downlinks, as they require idle channel estimation window positions or priori interference power thresholds, leading to resource wastage, complexity, and poor real-time performance.
Innovation Solution
A method involving rough estimation of interference power by selecting taps with less power and subsequent accurate estimation using SNR threshold post-processing, eliminating the need for idle channel estimation window positions or priori thresholds, with compensation for potential errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If idle channel estimation window positions are used to measure interference power, then measurement precision is improved, but device complexity and ease of operation deteriorate due to the need to obtain and manage idle window position information
Solution Approach 1:
The patent extracts the interference measurement function from the traditional idle window-based approach. Instead of requiring idle channel estimation windows, the invention uses all channel estimation windows and identifies interference response taps by detecting which taps do not contain signal response components (i.e., taps where the transmitted midamble code does not correlate with received signal). This extraction eliminates the need to identify and manage idle window positions while maintaining interference measurement capability.
Solution Approach 2:
The patent makes the interference measurement process universal by enabling it to work with all channel estimation windows regardless of whether they are idle or active. The method can be applied in both uplink and downlink scenarios without requiring specific window configurations. The base station can determine interference power using the same procedure whether windows are assigned for signal transmission or left idle, thus achieving multi-functionality across different operational modes.
2Measurement precision
If idle channel estimation windows are required for interference measurement, then measurement precision is improved, but ease of operation deteriorates as user terminals cannot obtain idle window position information in existing standards
Solution Approach 1:
The patent enables user terminals to perform interference power measurement autonomously without requiring network configuration or provision of idle window position information. The terminal uses its own transmitted midamble codes and received channel estimation results to identify interference response taps and calculate interference power. This self-service capability allows terminals to independently measure interference in both active and non-active time slots without relying on base station signaling for window position information.
3Reliability
If special channel estimation windows are defined and kept idle permanently or at specific frame cycles, then interference measurement capability is improved, but productivity deteriorates due to waste of system resources
Solution Approach 1:
The patent changes the fundamental parameter of interference measurement from requiring idle windows to using all windows with tap-level analysis. Instead of reserving specific windows as idle, the method analyzes individual taps within any channel estimation window to identify which ones contain interference responses. This parameter change allows full utilization of all channel estimation windows for both signal transmission and interference measurement, eliminating resource waste while maintaining measurement reliability.
4Measurement precision
If idle channel estimation window positions are obtained through broadcasting or signaling, then interference measurement precision is improved, but loss of time increases due to additional signaling overhead
Solution Approach 1:
The patent performs preliminary action by having the base station pre-determine and store the mapping relationships between channel estimation window indices and their corresponding midamble code shifts. When interference measurement is needed, the base station can immediately query this pre-computed information without requiring real-time signaling or calculation. This preliminary preparation eliminates time delays associated with obtaining window position information during actual measurement operations.
Data Source
AI summary
The present invention relates to a method for measuring interference power in a time slot CDMA system, The method includes: performing channel estimation for received signals with channel estimation codes, to obtain the original channel response estimation results hi, i=1 . . . P; predetermining a threshold of number of taps W1, and selecting the channel response estimation results for W1 taps with less power from the original channel response estimation results hi for W1 as the roughly estimated result of the interference power; performing threshold processing on the original channel response estimation results by post-processing against signal-to-noise ratio threshold, by using the roughly estimated result of the interference power and the predetermined signal-to-noise ratio threshold, before processing compensating the possible error generated from rough estimation of the interference power and performing threshold processing with the compensated power threshold, so as to ultimately obtain an accurate measured result of the interference power.