Phase Noise Tracking Algorithm for mmWave Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Millimeter wave (mmWave) communication systems face challenges in phase tracking, particularly due to severe phase noise from local oscillators, which degrades system performance and requires additional overhead in pilot symbols, limiting the ability to track phase noise effectively across data blocks.
Innovation Solution
A phase noise tracking algorithm that uses improved metrics for BPSK and QAM symbols, allowing for blind tracking of phase noise changes between data blocks with reduced complexity, utilizing the channel estimate from pilot blocks and simplified formulas to estimate small phase differences, thereby reducing the need for additional pilot symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional phase tracking methods are used in mmWave systems, then phase noise can be tracked with existing pilot symbols, but the tracking performance degrades due to severe phase noise and requires additional pilot overhead
Solution Approach 1:
The patent changes the parameter of phase difference estimation by using simplified formulas that assume small phase differences between consecutive data blocks. This parameter change allows effective phase tracking without requiring additional pilot symbols, thus improving measurement precision while avoiding increased pilot overhead
Solution Approach 2:
The patent performs preliminary channel estimation using pilot blocks before processing data blocks. The channel estimates obtained from pilot blocks are then reused for phase tracking in subsequent data blocks, eliminating the need for additional pilot symbols and reducing pilot overhead while maintaining tracking performance
2Measurement precision
If additional pilot symbols are added to track phase noise, then phase tracking performance improves, but system overhead increases and data throughput decreases
Solution Approach 1:
The patent makes the channel estimates from pilot blocks serve multiple functions: both for initial channel equalization and for subsequent phase tracking in data blocks. This multi-functionality eliminates the need for additional pilot symbols dedicated to phase tracking, thereby maintaining data throughput while achieving effective phase noise tracking
Solution Approach 2:
The patent changes the approach from using dedicated pilot symbols for phase tracking to using simplified phase difference calculations based on existing data block estimates. This parameter change in the tracking method allows phase noise compensation without consuming additional overhead resources, preserving data throughput
3Measurement precision
If complex phase tracking algorithms are used, then tracking accuracy improves, but computational complexity increases
Solution Approach 1:
The patent changes the computational approach by assuming small phase differences between consecutive data blocks, which allows using simplified formulas instead of complex algorithms. This parameter assumption reduces computational complexity while maintaining sufficient phase estimation accuracy for mmWave systems
Solution Approach 2:
The patent applies partial phase correction by only compensating for the phase difference between consecutive blocks rather than attempting to track absolute phase. This partial action approach reduces computational complexity while achieving the necessary tracking accuracy
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A group of data symbols for a current block of data symbols in multiple blocks received over a communication channel is equalized, based on a pilot block, to generate a group of equalized symbols. The group of equalized symbols is de-rotated as a function of a current phase estimate to determine initial de-rotated equalized symbols. The phase estimate is an estimate of phase caused by noise for blocks previous to the current block. Additionally, a phase metric is calculated from real and imaginary parts of the initial de-rotated equalized symbols, wherein the phase metric estimates phase caused by noise for the current block. The current phase estimate is updated with the phase metric. The initial de-rotated equalized symbols are de-rotated by the phase metric to determine final equalized and de-rotated symbol estimates. The final equalized and de-rotated symbol estimates are output. Apparatus, methods, and computer program products are disclosed.