MU-MIMO CQI Calculation via Inter-Cell Interference Feedback
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Solution Overview
Problem
In multi-user multiple-input multiple-output (MU-MIMO) wireless communications, calculating channel quality indicators (CQIs) at user equipment (UEs) consumes valuable processing and uplink signaling resources, as UEs lack information on spatial sub-channel usage schemes, leading to inaccurate CQIs and increased interference.
Innovation Solution
Generating inter-cell interference information at UEs and transmitting it to the base station, which then calculates CQIs using the equivalent channel matrix and usage scheme, allowing for accurate scheduling decisions without the need for multiple CQI calculations at UEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If UEs calculate multiple different CQIs for each spatial sub-channel usage scheme in MU-MIMO mode, then scheduling accuracy is improved, but UE processing resources and uplink signaling resources are consumed
Solution Approach 1:
Instead of having UEs calculate and feedback multiple CQIs for different spatial sub-channel usage schemes, the patent inverts the approach by having the eNB calculate the CQI using information received from UEs. The UE only needs to feedback inter-cell interference information, and the eNB uses this along with equivalent channel matrix and usage scheme to calculate the accurate CQI, thereby avoiding the complexity at the UE side while maintaining scheduling accuracy
Solution Approach 2:
The patent introduces inter-cell interference information as an intermediary element that bridges the UE and eNB. The UE measures and feedbacks this interference information to the eNB, which then uses it to calculate the CQI. This intermediary approach allows accurate CQI calculation at the eNB without requiring the UE to perform complex multiple CQI calculations
2Measurement precision
If UEs calculate multiple different CQIs for each spatial sub-channel usage scheme, then scheduling accuracy is improved, but uplink signaling resources are consumed
Solution Approach 1:
The patent extracts only the essential inter-cell interference information from the UE and transmits it to the eNB. This extracted information is sufficient for the eNB to calculate accurate CQIs without requiring the UE to transmit multiple complete CQI values. By taking out only the necessary interference parameters rather than all possible CQI combinations, the patent reduces uplink signaling overhead while maintaining scheduling accuracy
3Measurement precision
If the eNB calculates CQI using equivalent channel matrix and usage scheme, then scheduling accuracy is improved, but eNB processing complexity increases
Solution Approach 1:
The patent performs preliminary actions by having the eNB pre-store the equivalent channel matrix and usage scheme information. These pre-available resources allow the eNB to efficiently calculate CQI when inter-cell interference information is received from the UE, avoiding the need for complex real-time calculations while maintaining high scheduling accuracy
Data Source
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AI summary
A technique for operating a wireless communications system that supports multi-user multiple-input multiple-output (MU-MIMO) communications between a base station and multiple mobile stations involves generating inter-cell interference information at the mobile stations and providing the inter-cell interference information to the base station. The base station uses the inter-cell interference information to calculate channel quality indicators (CQIs) and then makes scheduling decisions in response to the CQIs. Data is transmitted from the base station to the mobile stations according to the scheduling decisions.