Heterogeneous Network Interference Reduction via Resource Decoupling
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Solution Overview
Problem
Wireless communication networks face interference issues in heterogeneous environments due to transmissions from neighbor base stations, which degrade performance on both downlink and uplink, and existing interference coordination techniques are inadequate in managing these interferences effectively.
Innovation Solution
Implementing enhanced inter-cell interference coordination (eICIC) techniques, where base stations negotiate to coordinate resources, allowing interfering cells to yield resources to reduce interference, and using resource partitioning strategies such as time-based and frequency-based subframe allocation to enable UEs to access serving cells with minimal interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If base stations transmit data on downlink and UEs transmit on uplink simultaneously in heterogeneous networks, then network capacity and resource utilization improve, but interference from neighbor base stations degrades performance
Solution Approach 1:
The patent segments the time-frequency resources by introducing almost blank subframes (ABS) where macro base stations reduce or eliminate transmissions. This segmentation creates interference-free time slots that allow pico base stations to serve UEs without macro interference, thereby resolving the contradiction between maintaining high network capacity and reducing inter-cell interference in heterogeneous networks
Solution Approach 2:
The patent implements dynamic resource allocation where the pattern of almost blank subframes is negotiated between macro and pico base stations based on traffic conditions and interference levels. This dynamic adjustment allows the system to adaptively balance between maximizing overall network capacity and minimizing interference to pico cells, rather than using static resource partitioning
2Reliability
If macro base stations reduce transmissions to minimize interference to pico cells, then pico cell performance improves, but macro cell resource utilization decreases
Solution Approach 1:
The patent changes the transmission parameter by introducing almost blank subframes where macro base stations dynamically adjust their transmission power or completely silence transmissions in specific time slots. This parameter change allows macro cells to maintain high resource utilization in non-ABS subframes while providing interference-free resources in ABS subframes, thus improving pico cell performance without permanently sacrificing macro cell capacity
Solution Approach 2:
The patent employs periodic almost blank subframe patterns where macro base stations cyclically reduce transmissions according to a negotiated pattern with pico base stations. This periodic action ensures that macro cells maintain high utilization during regular subframes while periodically providing interference-free slots to pico cells, balancing both macro and pico cell performance through time-multiplexed resource allocation
Data Source
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AI summary
Certain aspects relate to methods and apparatus for reducing interference in a heterogeneous network. Certain aspects relate to methods and apparatus for delinking downlink and uplink resource partitioning in a heterogeneous network. In aspects, the delinking is accomplished by reliably delivering uplink grant to a UE, e.g., pico UE in a pico CRE region, without using downlink Almost Blank Subframe (ABS) resources in which an interfering cell limits transmission to reduce interference to other victim cells. In techniques, instead of using the regular PDCCH sent in downlink ABS resources for uplink grant transmission, the uplink grant is sent on another more reliable downlink control channel using resources configured to avoid interference with transmissions from an interfering base station. In techniques, the DL grant is sent on PDCCH in non- downlink ABS resources, but the UE employs enhanced UE capabilities (e.g., interference cancellation) to process the received control information.