Cross-Cell Carrier Aggregation for Coverage Balance
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Solution Overview
Problem
Current LTE-Advanced carrier aggregation systems experience coverage imbalance due to significant frequency differences between primary and secondary carriers, limiting the benefits of carrier aggregation, especially when a user equipment (UE) moves outside overlapping coverage areas.
Innovation Solution
Implementing cross-cell carrier aggregation by separating the primary carrier base station from the secondary carrier base station, allowing for a denser deployment of higher frequency femto cells within the coverage area of low-frequency macro cells, thereby improving coverage balance without requiring additional frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is implemented with significant frequency differences between primary and secondary carriers, then bandwidth is increased and bitrates are improved, but coverage balance deteriorates and UE performance degrades when moving outside overlapping coverage areas
Solution Approach 1:
The patent segments the carrier aggregation function across multiple base stations (eNodeBs) rather than confining it to a single base station. The primary carrier is served by a first base station while the secondary carrier is served by a second base station, allowing each base station to independently manage its coverage area and frequency characteristics, thereby resolving the coverage imbalance issue
Solution Approach 2:
The patent introduces a network controller as an intermediary that coordinates between multiple base stations and user equipment. This controller manages the cross-base station carrier aggregation configuration, optimizing the selection of primary and secondary carriers from different base stations to maintain coverage balance while achieving high data rates
2Device complexity
If multiple component carriers are aggregated from a single base station section, then device complexity is reduced and control is simplified, but coverage area is limited and adaptability to heterogeneous networks is poor
Solution Approach 1:
The patent enables base stations to serve multiple functions: each base station can act as both a primary carrier provider and a secondary carrier provider for different user equipment. This multi-functionality allows the network to flexibly allocate carriers from different base stations based on coverage requirements, UE capabilities, and network conditions, thereby improving adaptability without significantly increasing device complexity
3Productivity
If higher frequency carriers are deployed to increase bandwidth, then capacity is improved, but coverage area decreases due to higher path loss
Solution Approach 1:
The patent segments the frequency spectrum utilization across multiple base stations, where low-frequency carriers with wide coverage are deployed by macro base stations and high-frequency carriers with high capacity are deployed by small cell base stations. This segmentation allows each frequency band to be optimally utilized for its characteristic strengths
Solution Approach 2:
The patent implements a nested deployment structure where small cell base stations operating on high-frequency carriers are deployed within the coverage area of macro base stations operating on low-frequency carriers. This nesting allows high-frequency carriers to provide capacity boosts in specific locations while the low-frequency macro carriers maintain overall coverage, effectively combining the advantages of both frequency bands
Data Source
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AI summary
A system and methods that are performed by a macro cell and a user equipment (UE) to implement a carrier aggregation mode in a network. The system includes a macrocell including a first coverage area and a plurality of small cells, each of the small cells including a second coverage area wherein the plurality of second coverage areas substantially cover the first coverage area. The macro cell operates a first component carrier as a primary component carrier in a carrier aggregation enabled network and one of the small cells operates a second component carrier as a secondary component carrier in the carrier aggregation enabled network.