Circular Polarization MIMO Data Transmission
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Solution Overview
Problem
MIMO technology in HSDPA systems causes interference for non MIMO user equipment due to independent channels for each data stream, leading to performance degradation for legacy terminals, as existing solutions like STTD and CLTD are complex and do not fully resolve the issue, especially in coexistence with non MIMO terminals.
Innovation Solution
The method employs two orthogonal circular polarizations for MIMO data streams, using a primary and secondary pilot channel, allowing non MIMO user equipment to correctly equalize channels by transmitting signals with left or right handed circular polarizations, maintaining independence for MIMO terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIMO technology is deployed with two independent data streams through orthogonal linear polarizations, then data transmission rate and spectrum efficiency are improved, but interference occurs for non MIMO user equipment causing performance degradation
Solution Approach 1:
The patent changes the polarization parameter from linear to circular polarization for the transmission of MIMO data streams. By using circular polarizations (right-handed and left-handed) instead of orthogonal linear polarizations, the system maintains the ability to transmit two independent data streams while ensuring that non MIMO terminals can properly equalize the channels without interference, as circular polarization allows the receiving antenna to receive both streams with the same channel characteristics.
2Object-affected harmful factors
If transmit diversity techniques like STTD or CLTD are used to reduce interference, then interference for non MIMO terminals is reduced, but system complexity increases and legacy terminal performance deteriorates
Solution Approach 1:
Instead of using transmit diversity techniques that add complexity to handle interference, the patent inverts the approach by changing the fundamental transmission parameter (polarization type) so that the interference problem disappears naturally. By using circular polarization, the system achieves the desired interference reduction without requiring complex transmit diversity processing, thereby simplifying the system while maintaining compatibility with legacy terminals.
3Reliability
If circular polarization is used for MIMO data streams, then non MIMO terminals can correctly equalize channels, but MIMO terminals may experience reduced channel independence
Solution Approach 1:
The patent applies different polarization characteristics to different parts of the transmission system. Specifically, it uses circular polarization for the transmission of MIMO data streams while maintaining the ability for MIMO terminals to process these streams independently. The circular polarization ensures that non MIMO terminals see the same channel characteristics for both streams, while MIMO terminals can still exploit the spatial independence through their MIMO processing capabilities, thus achieving local quality optimization for different terminal types.
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
This approach enables correct channel equalization for non MIMO terminals while preserving performance for MIMO terminals by ensuring both signals undergo the same modifications, thus avoiding interference and maintaining network performance.
Implementation Method 1
transmitting the first signal using a first circular polarization (Left Handed Circular LHC or Right Handed Circular RHC); transmitting the second signal using a second circular polarization which is orthogonal to the first circular polarization
Implementation Method 2
A non MIMO user equipment equalizes the channel by listening to a pilot signal transmitted together with its data
Data Source
AI summary
A method for data transmission in a wide area mobile network supporting both MIMO User Equipments and non MIMO User Equipments includes allocating in a first signal the traffic of non MIMO user Equipments, a first MIMO data stream and a primary pilot channel, allocating in a second signal a second MIMO data stream and a secondary pilot channel, and transmitting the first signal and the second signal with two orthogonal circular polarizations.