CQI Estimation Using Interference Segmentation in CoMP Systems
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Solution Overview
Problem
Current CoMP technology faces challenges in accurately obtaining Channel Quality Indication (CQI) due to interference measurement issues, leading to CQI mismatching and performance losses in cellular communication systems.
Innovation Solution
A method and apparatus that estimate interferences from both within and outside a CoMP measurement set to accurately calculate a target CQI, reducing overhead and improving system performance by considering interferences from multiple base stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If interference is measured only on interference measurement resource (IMR) in CoMP DPS scheme, then measurement process is simple, but CQI mismatching occurs leading to inaccurate channel quality indication
Solution Approach 1:
The interference measurement process is segmented into two independent parts: (1) measuring interference from IMR (existing simple process), and (2) estimating interference from CoMP set members using channel state information and CQI feedback. This segmentation allows the patent to maintain measurement simplicity while adding accuracy through the second part, resolving the contradiction between ease of operation and measurement precision.
Solution Approach 2:
The patent introduces channel state information (CSI) and CQI feedback as intermediary elements to bridge the gap between simple IMR measurement and accurate CQI calculation. These intermediaries enable the system to infer interference from CoMP set members without direct measurement, thus maintaining operational simplicity while improving measurement precision.
2Measurement precision
If multiple NZP CSI-RS resources are configured to emulate interference, then CQI accuracy improves, but system overhead increases significantly
Solution Approach 1:
The patent makes the system self-service by utilizing existing channel state information and CQI feedback that are already being transmitted and processed in the CoMP system. Instead of requiring additional dedicated resources for interference measurement, the system reuses existing data (channel state information from downlink reference signals and CQI feedback from UEs) to estimate interference, thereby improving accuracy without increasing overhead.
Solution Approach 2:
The patent changes the approach from physical resource allocation (configuring multiple NZP CSI-RS resources) to parameter-based estimation (using channel state information and CQI values to calculate interference). This parameter change allows the system to achieve accurate CQI measurement without the overhead associated with configuring additional physical reference signals.
3Device complexity
If adjacent cell CQI is calculated based on assumed PMI/RI, then calculation process is simplified, but link adaptation flexibility decreases and performance is lost
Solution Approach 1:
The patent employs feedback mechanisms by using actual CQI feedback from UEs and channel state information from downlink reference signals to calculate interference and determine CQI for CoMP set members. This feedback approach replaces simplified assumptions with real system data, thereby maintaining calculation simplicity while significantly improving link adaptation flexibility and system performance.
Data Source
AI summary
Embodiments of the disclosure provide a method and apparatus for obtaining a CQI in a communication system, wherein the communication system comprises a UE, a CoMP measurement set including more than one BS/point, and one or more outside BSs/points which is outside the CoMP measurement set, and wherein the UE is served by a serving BS/point in the CoMP measurement set and interfered by at least one interfering BS/point in the CoMP measurement set and the one or more outside BSs/points. In the method according to embodiments of the present invention, a first interference from at least one outside BS/point which is outside the CoMP measurement set to the UE is estimated; a second interference from at least one interfering BS/point in the CoMP measurement set to the UE is estimated; and a target CQI based on the first interference and the second interference is obtained.