Distributed Inter-Cell Interference Management via Weighted CQI

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current cellular radio systems lack a distributed algorithm to maximize overall throughput by minimizing inter-cell interference in a dynamic multi-cell environment, particularly in LTE systems, where the communication between base stations is not effectively optimized for near-optimal throughput.

Innovation Solution

A fully distributed solution for multi-cell orthogonal systems, where each cell's scheduler controls shared radio resources by receiving path gain measurements and cell-specific resource prices from interfered base stations, calculating user-specific weighted Channel Quality Indicator (CQI) values, and making scheduling decisions based on these values to minimize interference and maximize system throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If distributed base stations communicate to coordinate interference, then overall system throughput is improved, but communication overhead and system complexity increase

Engineering Contradiction:

Improveoverall system throughputVSAvoidcommunication overhead

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the interference coordination problem into cell-specific resource price calculations, where each base station independently calculates resource prices for its own cells based on local interference conditions. This segmentation reduces the need for extensive inter-base station communication while still achieving coordinated interference management across the network.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each base station determines resource prices locally based on its specific interference situation and channel conditions. The resource price for each resource block is calculated independently at each base station, allowing local optimization without requiring centralized control or extensive communication between base stations.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If resource prices are calculated for each resource block, then resource allocation precision is improved, but calculation complexity and signaling overhead increase

Engineering Contradiction:

Improveresource allocation precisionVSAvoidcalculation complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by calculating resource prices only for resource blocks that are actually used or potentially used in each cell. Instead of calculating prices for all possible resource blocks in the system, each base station focuses on its own active resource blocks, reducing calculation complexity while maintaining allocation precision for relevant resources.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If base stations exchange detailed interference information, then interference coordination accuracy is improved, but information exchange overhead increases

Engineering Contradiction:

Improveinterference coordination accuracyVSAvoidinformation exchange overhead

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent extracts only the essential information needed for interference coordination by having base stations calculate and exchange resource prices rather than exchanging detailed interference measurements and channel state information. This extraction approach maintains coordination accuracy while significantly reducing the amount of information that needs to be exchanged between base stations.

Inventive Principle:

Principle #2Taking out (Extraction)

4Productivity

If dynamic scheduling decisions are made based on weighted CQI, then user throughput is improved, but processing requirements at base station increase

Engineering Contradiction:

Improveuser throughputVSAvoidprocessing power

Core Design Contradiction:

ProductivityVSPower

Solution Approach 1:

The patent applies preliminary action by calculating resource prices in advance based on interference conditions and channel quality. These pre-calculated resource prices are then used in the scheduling decision process, reducing the real-time processing requirements at the base station while still enabling dynamic and optimized scheduling decisions that improve user throughput.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8229451B2Method and arrangement for managing inter-cell interference in a communications network

Publication Date: 2012.07.24 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

The present invention relates to a method in a base station (110a, 110b, 210a, 210b, 210c, 410a, 410b) for managing inter-cell interference in a communications network, comprising a scheduler in each cell which controls a set of shared radio resources, said radio resources being at least near orthogonal to each other. The method comprises the steps of: obtaining (601) data representing path gain measurements, obtaining (602) data representing a cell specific resource price from one or several interfered base stations, combining (603) said information into a user specific resource price value for each radio resource, calculating (604) a user specific weighted channel quality indication value for each radio resource by combining a channel quality indication (CQI) information available for each given user with at least a product of said user specific resource price and the required transmit power for each user, and making (605) a scheduling decision based on said user specific weighted CQI values.