ABS Pattern for Interference Control in Heterogeneous Networks
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Solution Overview
Problem
In heterogeneous network systems, there is a challenge in balancing the load between macro and pico cells, leading to interference from macro cells to user equipment (UE) within the extended coverage of pico cells, which degrades network throughput and user experience.
Innovation Solution
The implementation of an Almost Blank Subframe (ABS) pattern is used to allocate radio resources, where certain subframes are designated as ABS or non-ABS based on the type of data transmitted, reducing interference from macro cells to UE in the extended coverage area of pico cells, allowing for stable data communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If UEs select the cell with the highest RSRP as their serving cell, then signal strength is maximized, but interference from macro cell to pico cell UEs increases and total network throughput degrades
Solution Approach 1:
The time domain is segmented into Almost Blank Subframes (ABS) and Non-ABS subframes. During ABS, the macro cell transmits only reference signals at reduced power, creating interference-free time slots for pico cell UEs. This temporal segmentation allows UEs to select based on RSRP while preventing macro cell interference during critical reception periods.
Solution Approach 2:
The ABS pattern is configured periodically with a predetermined period (e.g., 40ms). The macro cell alternates between ABS and non-ABS subframes in a periodic manner, creating regular interference patterns that pico cell UEs can exploit for reliable communication during ABS periods while maintaining connection to the macro cell during non-ABS periods.
2Productivity
If CRE technique is used to balance load between macro and pico cells, then load balancing is improved, but UEs connected to pico cell due to CRE bias still suffer interference from macro cell
Solution Approach 1:
The ABS pattern is configured in advance before data communication occurs. The macro cell pre-establishes the ABS pattern and signals it to pico cell UEs, allowing UEs to prepare for interference-free reception during ABS periods. This preliminary configuration enables CRE UEs to connect to pico cells with reduced anxiety about macro cell interference.
Solution Approach 2:
The ABS pattern acts as an intermediary mechanism between the macro cell and pico cell UEs. Instead of directly reducing macro cell power or blocking signals, the ABS pattern creates structured time slots where the macro cell voluntarily reduces transmission, serving as a mediator that enables coexistence and protects pico cell UEs during their critical reception windows.
3Object-affected harmful factors
If ABS pattern is applied to control interference, then interference mitigation is achieved, but resource allocation complexity increases
Solution Approach 1:
Instead of fundamentally changing the resource allocation architecture, the solution modifies the transmission power parameter of the macro cell in specific subframes. By changing the power level from full power to reduced power during ABS, the system achieves interference mitigation while maintaining the existing ABS pattern framework and resource allocation procedures.
Data Source
AI summary
The present invention relates to a method and an apparatus for applying wireless resources in order to control inter-cell interference in a heterogeneous network system. The method for applying wireless resources provided by the present invention generates an almost blank subframe (ABS) pattern on the basis of the type of data transmitted from at least one of a first base station and a second base station, applies a non-ABS or an ABS to wireless resources of the first base station according to the generated ABS pattern, and performs data communication by using the wireless resources to which the ABS has been applied.