Hybrid Massive MIMO Channel Sounding via Analog Phase Weights
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Solution Overview
Problem
Massive MIMO systems face challenges in channel sounding accuracy and capacity performance due to reduced port counts, leading to attenuated signals and distorted beam patterns, which increase implementation costs and complexity while reducing coverage and data rates.
Innovation Solution
The use of digitally controlled analog phase shifters and a resource mapping and precoding block to dynamically steer beams and combine Precoding Matrix Indicators (PMIs) with digital control values, eliminating the need for beam steering via precoding matrices and reducing unwanted sidelobes, thereby enhancing channel sounding and data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of ports is reduced to decrease implementation cost and complexity, then device complexity and cost are reduced, but maximum scan angle coverage and channel sounding accuracy deteriorate
Solution Approach 1:
Analog phase shifters are introduced as intermediary components between the reduced port count and the antenna array. These phase shifters dynamically adjust beam directions to compensate for the limited number of ports, enabling the system to achieve coverage equivalent to higher port count systems without the corresponding increase in hardware complexity
Solution Approach 2:
The system employs dynamic beam steering through time-varying analog phase shifter control. By continuously adjusting beam directions based on channel state information, the system adapts to different spatial conditions and maintains accurate channel sounding despite the reduced number of ports
2Device complexity
If each port drives multiple antenna elements to reduce port count, then device complexity and cost are reduced, but beam resolution and sidelobe generation worsen
Solution Approach 1:
Analog phase shifters serve as intermediaries that enable independent control of beam directions for each port. This allows the system to maintain high beam resolution and eliminate sidelobes even with a reduced port count, as each port can be independently steered to its optimal direction without sharing antenna elements
Data Source
AI summary
A method involving a MIMO communications system including a phased array antenna for establishing communication with a terminal located within a domain, the method including: defining a plurality of sub-domains within the domain; for each sub-domain, defining a corresponding set of analog phase weights to be applied to the phased array antenna for directing beams towards that sub-domain; in succession, selecting each sub-domain among the plurality of sub-domains and for each selected sub-domain: (a) applying the set of analog phase weights for that selected sub-domain to the phased array antenna; (b) performing channel sounding with the terminal while that sub-domain is selected; and (c) receiving feedback from the terminal for that selected sub-domain; and after selecting all sub-domains and from the received feedback, identifying a best sub-domain and identifying a best precoding matrix that in combination with the best sub-domain provides a best communication channel for the terminal.