Phase Noise Suppression in MIMO Co-Reference Systems
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Solution Overview
Problem
Current phase noise suppression methods for MIMO systems, especially in co-reference architectures, face challenges in effectively estimating and suppressing phase noise, leading to poor performance and high costs, particularly at high-frequency bands, due to the complexity of power allocation and limited ability to handle independent phase noise.
Innovation Solution
The method divides phase noise into common and independent components, constructs joint phase states for independent noise, calculates log likelihood values and a multi-channel decorrelation coefficient matrix, inserts pilots for common noise estimation, and performs signal demodulation based on posterior log likelihood values to optimize phase noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent local oscillators are used for each channel, then phase noise of different channels is not correlated, but the degree of freedom of phase noise increases to NtNr, making it difficult to ensure good phase noise estimation and suppression performance
Solution Approach 1:
The patent segments phase noise into two distinct components: common phase noise (affecting all channels equally) and independent phase noise (affecting each channel separately). This segmentation allows the system to handle the common component through shared estimation and the independent components through individual processing, thereby reducing the overall complexity from NtNr degrees of freedom to a more manageable level while maintaining suppression performance.
2Reliability
If independent local oscillators are used for each channel, then phase noise can be handled per channel, but periodic channel estimation is required, resulting in large pilot overhead and significant impact on throughput
Solution Approach 1:
The patent merges the estimation of common phase noise across all channels by exploiting the correlation property. Instead of performing separate channel estimations for each channel, the system performs a single common phase noise estimation that benefits all channels simultaneously. This merging approach dramatically reduces pilot overhead while maintaining accurate phase noise compensation for each channel.
3Reliability
If a local oscillator is shared among channels, then phase noise of different channels is identical and suppression can be performed using SISO methods, but power allocation on high-frequency oscillator is characterized by complicated implementation structure, large loss, and high cost
Solution Approach 1:
The patent segments the local oscillator architecture into two parts: a shared low-frequency reference oscillator that generates common phase noise, and channel-specific frequency multipliers that generate independent phase noise. This segmentation allows power allocation to be performed on the low-frequency reference signal where technology is mature and cost-effective, while still accounting for independent phase noise components in the suppression algorithm.
Solution Approach 2:
The patent introduces frequency multipliers as intermediary devices between the shared low-frequency reference oscillator and the high-frequency channel signals. These multipliers convert the common low-frequency reference into channel-specific high-frequency signals, creating a hierarchical structure that reduces implementation complexity and cost while maintaining the ability to suppress both common and independent phase noise components.
4Ease of manufacture
If frequency multipliers are used to generate local oscillator signals from a common low-frequency reference, then power allocation is simplified, but phase noise consists of common phase noise and independent phase noise, for which no suppression method existed in existing solutions
Solution Approach 1:
The patent segments phase noise into common and independent components, enabling targeted suppression strategies for each type. The common phase noise is suppressed through shared estimation across all channels, while independent phase noise is handled through channel-specific processing. This segmentation resolves the previously unsolved problem of suppressing independent phase noise in co-reference architectures.
Solution Approach 2:
The patent performs preliminary separation and characterization of common and independent phase noise components before the actual suppression process. By预先 (in advance) identifying and modeling these two distinct noise components, the system can apply appropriate suppression techniques to each, thereby achieving reliable phase noise suppression in co-reference architectures where it previously did not exist.
Data Source
AI summary
A phase noise suppression method for a multiple-input multiple-output (MIMO) system with a plurality of co-reference channels includes: dividing the phase noise of each channel in the MIMO system into common phase noise and independent phase noise, and constructing a certain number of joint phase states for the independent phase noise; inserting a pilot sequence into the sent signal based on a preset cycle, obtaining the common phase noise based on the pilot at receiver, and performing compensation; and performing signal demodulation on each joint state of the independent phase noise, and comparing the posterior log likelihood values to select the optimal result to output. The above method can significantly improve the phase noise suppression performance of the MIMO system with a plurality of co-reference channels, thereby providing support for improving the system capacity by using MIMO technology.