MIMO Base Station Spatial Resolution Interference Control
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Solution Overview
Problem
Conventional cellular MIMO systems face challenges in distinguishing and managing signal transmissions between terminals that are close to each other, leading to increased interference and reduced throughput due to limitations in spatial resolution.
Innovation Solution
The system selectively activates multiple access methods such as TDMA, FDMA, or CDMA for terminals that cannot be distinguished by spatial diversity, allowing them to share common channels and allocate bandwidths dynamically based on error rates and spatial footprints, thereby reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spatial diversity multiple access is used to focus radio energy on terminals, then capacity and radiated energy efficiency are improved, but interference increases when terminals are located closer than the spatial resolution
Solution Approach 1:
The system dynamically switches between spatial diversity multiple access and other multiple access methods (TDMA, FDMA, CDMA) based on real-time monitoring of indicators such as error rates and signal quality. When terminals move closer than the spatial resolution threshold, the base station detects increased interference and transitions from static spatial diversity to dynamic hybrid multiple access, resolving the contradiction between capacity and interference.
Solution Approach 2:
The base station monitors parameters such as error rates, signal-to-interference ratios, and terminal positions to detect when spatial resolution is insufficient. Based on these parameter changes, the system adjusts the multiple access method, transitioning from pure spatial diversity to alternative methods when parameters indicate terminal proximity below the resolution threshold, thereby maintaining low interference while preserving capacity.
2Use of energy by moving object
If the base station uses a large number of antennas for spatial focusing, then radiated energy efficiency is improved, but the ability to distinguish close terminals deteriorates when terminals are within the spatial resolution limit
Solution Approach 1:
The system segments the multiple access approach by combining spatial diversity (using the antenna array for energy focusing) with alternative multiple access methods (TDMA, FDMA, or CDMA) for terminal differentiation. When spatial resolution is insufficient, the base station activates complementary access methods that operate in different domains (time, frequency, or code), allowing the antenna array to maintain its energy efficiency while the segmented approach handles terminal distinction.
3Object-affected harmful factors
If alternative multiple access methods are activated for all terminals, then interference is reduced, but throughput decreases due to channel sharing requirements
Solution Approach 1:
The system applies alternative multiple access methods locally and selectively only to terminals that are located closer than the spatial resolution threshold and cannot be distinguished by spatial diversity alone. Terminals that are sufficiently separated continue to use pure spatial diversity multiple access, maintaining high throughput. This localized application ensures interference reduction is achieved only where necessary, preserving overall system throughput.
Solution Approach 2:
The base station monitors system conditions and automatically activates alternative multiple access methods only when and where needed, based on detected interference levels and terminal positions. The system self-adjusts without requiring manual intervention, activating diversity methods selectively for terminal pairs experiencing interference while leaving other terminals on high-throughput spatial diversity, thereby maintaining optimal overall throughput.
Data Source
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AI summary
A cellular multiple-input and multiple-output, MIMO, system, has a base station. The base station has a plurality of antennas. To control a signal transmission in the MIMO system, the base station monitors at least one indicator which indicates whether a spatial resolution of the plurality of antennas allows signals received from at least two terminals to be distinguished. The base station selectively activates a multiple access transmission and reception for the at least two terminals as a function of the at least one indicator. The multiple access transmission and reception causes the at least two terminals to share a common channel.