Inter-Cell Interference Coordination Using Limited Channel State Information
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Solution Overview
Problem
Conventional inter-cell interference coordination techniques in heterogeneous networks face challenges due to the assumption of complete channel state information, which is not consistent with actual situations, and the inability to perform adaptive resource assignment based on channel states, leading to performance deterioration in mobile communication environments.
Innovation Solution
A method and apparatus for inter-cell interference coordination using limited channel state information, which involves probabilistic modeling of channels between large cell base stations and small cell terminals, and the use of a channel model to control interference by determining an optimal ratio of subframes for data transmission, maximizing sum network throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complete channel state information is assumed for interference coordination, then adaptive resource assignment can be performed, but this assumption is not consistent with actual situations where channel state information is limited
Solution Approach 1:
The patent implements a feedback mechanism where terminals periodically feed back channel quality indicators (CQI) and interference measurements to the base station. This feedback loop enables the base station to make adaptive resource assignment decisions based on actual channel conditions rather than assuming complete channel state information, thus resolving the contradiction between adaptability and information loss.
Solution Approach 2:
The patent introduces statistical channel models and probabilistic interference models as intermediaries between the limited channel state information available at terminals and the resource assignment decisions made at the base station. These models bridge the information gap by providing estimated channel statistics and interference characteristics that enable adaptive resource assignment without requiring complete channel state information.
2Productivity
If Range Expansion technique is used to increase small cell coverage, then small cell utilization increases, but interference from large cell base station deteriorates performance
Solution Approach 1:
The patent applies local quality by implementing interference coordination specific to terminals affected by range expansion. The base station identifies terminals in extended coverage areas and applies targeted resource allocation strategies, such as assigning these terminals to specific subframes where large cell interference is minimized, while other terminals use normal resource allocation. This localized approach allows small cell utilization to increase while protecting vulnerable terminals from interference deterioration.
Solution Approach 2:
The patent implements periodic action through the use of interference coordination patterns where the large cell base station periodically transmits reference signals and channel state information, and where resource allocation patterns are established with specific periodicities. Terminals in range expansion areas are assigned to specific periodic subframes where interference is coordinated, allowing small cell utilization to improve while managing interference through structured periodic transmission patterns.
3Object-affected harmful factors
If conventional ICIC techniques are used to prevent large cell transmission during predetermined periods, then interference is reduced, but network throughput is not optimized due to lack of channel state information utilization
Solution Approach 1:
The patent implements dynamics by transitioning from static interference coordination patterns to dynamic resource allocation that adapts to changing channel conditions. The base station continuously updates resource allocation decisions based on feedback from terminals about current channel quality and interference levels. This dynamic approach allows the system to reduce interference when necessary while maximizing network throughput by utilizing available channel state information to make real-time optimization decisions.
Solution Approach 2:
The patent applies parameter changes by adjusting resource allocation parameters such as modulation and coding schemes, resource block assignments, and transmission power based on measured channel state information and interference levels. Instead of using fixed predetermined transmission avoidance periods, the system dynamically changes these parameters to optimize the trade-off between interference reduction and network throughput, utilizing actual channel statistics rather than conservative fixed patterns.
Data Source
AI summary
Disclosed herein are an apparatus and method of performing inter-cell interference coordination in a heterogeneous network. The apparatus includes a reception unit, a determination unit, a generation unit, and a transmission unit. The reception unit receives a modulation and coding scheme (MCS) level from a small cell base station in each frame. The determination unit determines a calculated MCS level based on the MCS level and an interfering signal estimated through probabilistic modeling. The generation unit generates a ratio of subframes, in which data will not be transmitted, to all subframes of a frame based on the MCS level and the calculated MCS level. The transmission unit transmits the ratio and the calculated MCS level to the small cell base station.