Blind Channel Estimation for Massive MIMO Pilot Contamination
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Solution Overview
Problem
Current wireless communication systems, particularly in massive MIMO networks, face challenges with pilot contamination that degrades performance due to limited orthogonal pilot sequences, leading to inefficient resource allocation and interference among users.
Innovation Solution
A network node device and method that multiplexes data from multiple users using non-orthogonal and orthogonal resource elements, allowing blind data detection to estimate spatial channels without relying on uplink pilot resources, thereby avoiding pilot contamination and optimizing spectral resource utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If orthogonal pilot sequences are allocated for channel estimation, then channel estimation accuracy is improved, but spectral efficiency deteriorates due to substantial resource allocation for pilots
Solution Approach 1:
The patent extracts the channel estimation function from dedicated orthogonal pilot sequences and implements it through blind detection using data sequences. The receiver separates channel estimation from data detection by exploiting the statistical properties of data sequences, thereby eliminating the need for separate pilot resources and improving spectral efficiency while maintaining estimation accuracy
Solution Approach 2:
The data sequences serve dual purposes: they carry user information and simultaneously enable channel estimation. By designing the system to exploit the structure of data sequences for both transmission and channel characterization, the patent makes the data sequences multi-functional, eliminating the need for separate orthogonal pilot sequences
2Object-affected harmful factors
If the number of orthogonal pilot sequences is increased to reduce pilot contamination, then pilot contamination is reduced, but device complexity and resource overhead increase
Solution Approach 1:
The system eliminates the need for external pilot sequence management by enabling self-service channel estimation through blind detection. The receiver autonomously estimates channels by processing data sequences without requiring coordinated allocation or management of orthogonal pilot sequences, thereby eliminating pilot contamination while reducing system complexity
Solution Approach 2:
The patent changes the fundamental parameter from using orthogonal pilot sequences to using data sequences for channel estimation. This parameter change transforms the approach from one requiring multiple orthogonal sequences to one that works with existing data sequences, thereby eliminating pilot contamination without increasing complexity
3Measurement precision
If half of time-frequency resources are allocated for channel estimation in massive MIMO, then channel estimation performance is improved, but loss of time and frequency resources increases
Solution Approach 1:
The patent extracts the channel estimation capability from dedicated time-frequency pilot resources and implements it through blind detection using data sequences. This extraction eliminates the need to allocate half of time-frequency resources for pilots, thereby reducing resource loss while maintaining estimation performance through sophisticated signal processing of data sequences
Solution Approach 2:
The system performs channel estimation preliminarily and continuously through blind detection during data transmission periods. By continuously exploiting the statistical properties of incoming data sequences, the system maintains up-to-date channel estimates without requiring separate preliminary pilot transmission phases, thereby eliminating time-frequency resource loss
Data Source
Figure 1A~1B
Figure 2A
Figure 2B~2D
AI summary
According to a first aspect a network node device is provided, comprising: a radio transceiver configured to receive a data sequence from a plurality of user equipment over first and second sets of resource elements, wherein the first set is mapped non-orthogonally and the second set is mapped orthogonally. The network node device further comprises a processor configured to determine channel vectors based on at least the data sequence received over the first set of resource elements or the second set of resource elements, and to utilize the data sequence received over the second set of resource elements to associate the determined channel vectors with each of the plurality of user equipment.