Uplink Noise Power Estimation Using Unused Channelization Code
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Solution Overview
Problem
Existing communication systems face limitations in accurately separating signal and noise power in received waveforms due to assumptions that require pre-known signal bits and an infinite number of symbols for averaging, leading to slow adapting speed and limited application in uplink communication.
Innovation Solution
A method and uplink receiver design that despreads received signals using an unused channelization code to create a virtual noise channel, canceling noise power without relying on correlation functions or pre-known signal bits, allowing for real-time noise power determination and signal processing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correlation function based algorithm is used to separate signal and noise power, then signal and noise power can be separated, but the algorithm requires assumption of zero correlation remainders which stands only if infinite number of symbols are used for averaging, resulting in slow adapting speed
Solution Approach 1:
Instead of using the received signal directly and subtracting signal power to get noise power, the patent inverts the approach by using an unused orthogonal code to despread the received signal. This creates a virtual noise channel where only noise components appear, eliminating the need for correlation remainder assumptions and enabling fast noise power estimation without requiring infinite symbol averaging.
Solution Approach 2:
The patent introduces an unused orthogonal code as an intermediary element. This code serves as a mediator to create a virtual noise channel that isolates noise components from signal components. By using this intermediary code for despreading, the system can directly observe noise power without being contaminated by signal components, thus resolving the contradiction between measurement precision and adapting speed.
2Measurement precision
If correlation function based algorithm is used, then noise power can be determined, but it requires assumption that signal bits are pre-known, limiting application to pilot signals only
Solution Approach 1:
The patent extracts the noise component from the received signal by using an unused orthogonal code for despreading. This extraction process isolates the noise power from the mixed signal-noise waveform without requiring knowledge of the signal bits. The virtual noise channel created by this extraction contains only noise components, enabling noise power determination to be applied universally to all signal types including data channels, not just pilot signals.
3Speed
If small number of symbols are used for averaging to meet fast changing transmission conditions, then adapting speed improves, but the assumption of zero correlation remainders cannot be met, reducing measurement precision
Solution Approach 1:
The patent inverts the traditional approach by not trying to estimate noise power from the mixed signal by subtracting signal power (which requires many symbols for accurate averaging). Instead, it uses an unused orthogonal code to directly extract noise components, creating a virtual noise channel where noise power can be accurately measured with fewer symbols since no correlation remainder assumptions are needed.
Data Source
AI summary
In one embodiment, the method includes receiving signals from user equipment, despreading the received signals by applying an unused channelization code, and determining the uplink noise power based on output of the despreading.