Network Optimization via Cell Selection Bias and Almost Blank Subframes
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Solution Overview
Problem
Heterogeneous networks (HetNets) face challenges in optimizing network performance due to underutilization of pico base stations and excessive interference from macro stations, leading to inefficient resource allocation and low downlink throughput.
Innovation Solution
A method involving a distributed optimization framework that adjusts transmission power and interference coordination using a potential game model, specifically through the use of almost blank subframes and cell selection biases, to optimize network performance and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pico base stations transmit at low power levels, then installation cost is reduced and site availability issues are mitigated, but mobile users near pico BSs are attracted to macro BSs causing underutilized pico BSs and overcrowded macro BSs
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the cell selection bias parameter to control user association between macro and pico base stations. By changing this parameter, the system can shift user distribution to optimize pico BS utilization while maintaining cost-effective low-power transmission
Solution Approach 2:
The patent implements feedback mechanisms where the network controller monitors pico BS utilization and macro BS load conditions, then adjusts cell selection bias parameters accordingly. This closed-loop control ensures that pico BSs are effectively utilized while preventing macro BS overcrowding
2Ease of manufacture
If pico base stations transmit at low power levels, then installation cost is reduced, but surrounding macro BSs generate large interference to pico BS users resulting in very low downlink throughputs
Solution Approach 1:
The patent applies periodic action through almost blank subframes (ABS) where macro base stations periodically transmit blank or reduced-power signals. This periodic interference coordination allows pico BS users to experience improved downlink throughput during protected subframes while maintaining the cost benefits of low-power pico transmission
Solution Approach 2:
The patent implements preliminary anti-action by pre-configuring ABS patterns and cell selection biases to anticipate and prevent interference issues before they occur. This proactive approach ensures that pico BS users are protected from macro BS interference while maintaining economical low-power operation
3Productivity
If cell densification is implemented with more base stations, then network capacity is increased, but the complexity of network management and optimization increases
Solution Approach 1:
The patent applies merging by combining multiple base stations (macro and pico) into hierarchical clusters with centralized controllers. This consolidation approach increases network capacity while managing complexity through unified control mechanisms that coordinate resource allocation and interference management across the densified network
Data Source
AI summary
A method of optimising a network includes selecting an operating characteristic of a network to optimise; determining at least one operating parameter of network nodes within the network which affects the operating characteristic; selecting an optimisable network node from within the network; identifying a cluster of the network nodes whose operating characteristic is affected by a change in the at least one operating parameter of the optimisable network node; iteratively adjusting the at least one operating parameter of the optimisable network node; determining the operating characteristic of the cluster of the network nodes in response to that adjusted at least one operating parameter of the optimisable network node; and selecting that adjusted at least one operating parameter of the optimisable network node which improves the operating characteristic of the cluster of the network nodes.