Distributed Antenna System MIMO Frequency Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional distributed antenna systems (DAS) face challenges in supporting Multiple Input Multiple Output (MIMO) services without the need for additional cables, as MIMO technology requires multiple antennas to transmit and receive signals sharing a common frequency band, leading to mutual interference.
Innovation Solution
A distributed antenna system that uses frequency conversion to separate MIMO downlink signals into non-overlapping frequency bands, allowing them to be transmitted over a single transmission line, with nodes configured to perform frequency conversion at both the first and second nodes to reconstruct the original frequency bands, thereby avoiding mutual interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If MIMO signals are transmitted over a single transmission line without frequency conversion, then device complexity is reduced, but mutual interference occurs between MIMO signals sharing the common frequency band
Solution Approach 1:
The patent applies frequency conversion to change the frequency parameter of MIMO signals. Specifically, it converts MIMO downlink signals from a common frequency band to different frequency bands at the first node, transmits them over a single transmission line without interference, and then converts them back to the original frequency band at the second node. This parameter change resolves the mutual interference problem while maintaining the simplicity of using a single transmission line.
Solution Approach 2:
The patent introduces frequency conversion as an intermediary process between signal transmission and reception. The frequency conversion at the first node acts as a mediator to separate MIMO signals into different frequency bands before transmission, and the conversion at the second node mediates the restoration of signals to their original frequency band, thereby enabling interference-free transmission over a single line.
2Object-generated harmful factors
If additional coaxial or fiber optic cables are installed to support MIMO services, then mutual interference between MIMO signals is avoided, but device complexity and installation cost increase
Solution Approach 1:
Instead of adding physical cables, the patent changes the frequency parameter of existing signals to eliminate interference. By converting MIMO downlink signals to different frequency bands and back, the system achieves interference-free transmission using the existing single transmission line, avoiding the need for additional cables and the complexity they introduce.
Solution Approach 2:
The patent replaces the mechanical solution of installing additional cables with an electronic/frequency-domain solution. Rather than physically separating MIMO signals through multiple cables, the system uses frequency conversion to separate and combine signals electronically, substituting a mechanical approach with an electromagnetic field-based approach.
3Object-generated harmful factors
If MIMO downlink signals are frequency-converted to different frequency bands, then mutual interference is eliminated during transmission, but signal processing complexity increases
Solution Approach 1:
The patent segments the MIMO signal processing into distinct stages: frequency conversion at the first node, transmission over the single line, and frequency conversion back at the second node. This segmentation allows each node to perform focused signal processing tasks, managing complexity by dividing the overall processing function across multiple components rather than requiring all processing at a single point.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the support of LTE services using MIMO technology without the need for additional cables, maintaining signal quality and reducing complexity in signal processing and amplifier requirements.
Implementation Method 1
perform, for each MIMO service, a frequency conversion of N−1 MIMO downlink signals from among the N MIMO downlink signals, to a different frequency band from an original frequency band
Implementation Method 2
perform, for each MIMO service, a frequency conversion of the MIMO downlink signals that have been frequency-converted by the first node, in a complementary manner, to reconstruct the MIMO downlink signals of the original frequency band
Data Source
AI summary
A distributed antenna system supporting MIMO service is disclosed. Some embodiments provide a distributed antenna system supporting MIMO communication, including first node, second node and one transmission line. The first node receives MIMO downlink signals of a plurality of MIMO services each including N (a natural number of 2 or more) MIMO downlink signals, and performs, for each MIMO service, frequency-conversion of N−1 MIMO downlink signals among the N MIMO downlink signals, to different frequency band from original frequency band, to generate N MIMO downlink signals without mutually overlapping frequency bands. The second node performs, for each MIMO service, frequency-conversion of the MIMO downlink signals having been frequency-converted by first node, in a complementary manner, to reconstruct the MIMO downlink signals of original frequency band. The single transmission line is used between the first node and second node for transmitting N downlink signals without mutually overlapping frequency bands.