Macro eNB ABS Pattern Allocation for Heterogeneous Network Interference
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Solution Overview
Problem
Heterogeneous networks (HetNets) face challenges in maximizing throughput due to inter-cell interference issues, particularly when expanding the range of small cell eNBs, which can lead to deteriorated overall sum capacity and low link performance for small cell UEs, and macro UEs cannot be serviced using macro ABS patterns for small cell range expansion.
Innovation Solution
Implementing a method for performing carrier aggregation (CA) using multiple almost blank subframe (ABS) patterns in a macro eNB, where different ABS patterns are determined for each component carrier, and a serving cell is determined for each user equipment (UE) among macro and small cells, allowing for coordinated data transmission based on the determined serving cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If small cell eNB range is expanded by increasing Tx power, then coverage area is improved, but inter-cell interference increases and overall sum capacity deteriorates
Solution Approach 1:
The patent applies periodic action by implementing Almost Blank Subframes (ABS) where the macro eNB periodically transmits reference signals and control information while reducing or eliminating data transmission in specific subframes. This periodic transmission pattern allows small cell UEs to receive signals during designated subframes with minimized interference from the macro eNB, thereby expanding coverage without proportionally increasing inter-cell interference.
2Area of stationary object
If small cell eNB range is expanded by giving positive offset to DL RSS, then coverage area is improved without increasing Tx power, but link performance of small cell UEs deteriorates due to strong interference from macro eNB
Solution Approach 1:
The patent implements periodic action through ABS patterns where the macro eNB schedules reference signal transmissions and control information in specific subframes while remaining silent or transmitting at reduced power in other subframes. This creates periodic low-interference windows that allow small cell UEs to maintain reliable links even with range expansion offset applied, as they can receive signals during macro eNB's blank subframes.
Solution Approach 2:
The patent applies local quality by providing different ABS pattern configurations to different small cell UEs based on their specific channel conditions and locations. Each UE receives customized ABS patterns that optimize its individual link performance, allowing the system to maintain high reliability across the expanded coverage area while accommodating varying interference conditions at different spatial locations.
3Productivity
If macro UE is located at boundary of macro cell, then offloading to small cell eNB improves macro cell capacity, but small cell UE in range expansion area suffers from low link performance
Solution Approach 1:
The patent applies periodic action by configuring different ABS patterns for different UEs based on their serving cell and location. Macro UEs at cell boundaries can be offloaded to small cells during ABS periods when macro interference is reduced, while small cell UEs in range expansion areas receive enhanced protection through customized ABS patterns that ensure reliable link performance. This differentiated periodic scheduling allows the system to simultaneously improve macro cell capacity through offloading and maintain high reliability for all UEs.
Data Source
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AI summary
Methods and apparatuses are provided for performing carrier aggregation (CA) using a plurality of almost blank subframe (ABS) patterns in a macro enhanced Node B (eNB) of a wireless communication system connected to a heterogeneous network. An ABS pattern having a different pattern is determined for each component carrier (CC), when two or more carriers are deployed in each of the macro eNB and at least one small cell eNB. A serving cell for each user equipment (UE) is determined for each CC, from among a macro cell and a small cell. CA is performed for data transmission to each UE using the determined ABS pattern, in accordance with each determined serving cell.