Cell Configuration for Carrier Aggregation in Wireless Systems
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Solution Overview
Problem
In wireless communication systems, especially in LTE-A networks, MIMO transmission is restricted at cell edges due to interference from sectors using the same frequency, leading to limited data rates and modulation orders, especially when carrier aggregation is used, as it complicates RLC entity splitting and interferes with signal reception.
Innovation Solution
The solution involves configuring base stations and terminals to use the same Physical Cell Identifier (PCID) for certain component carriers, allowing for MIMO transmission across multiple cells, which enables high modulation orders and data rates by optimizing cell configuration based on UE mobility and load conditions, and selecting primary and secondary cells to compensate for interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MIMO transmission is used in LTE-A networks, then transmission efficiency is improved, but interference from sectors using the same frequency restricts MIMO transmission at cell edges
Solution Approach 1:
The network is segmented into multiple cells with different PCID configurations. Some cells use the same PCID while others use different PCIDs, allowing the system to divide the coverage area into regions where MIMO can be effectively applied without suffering from severe inter-sector interference
Solution Approach 2:
Different PCID allocation strategies are applied to different cells based on local conditions. Cells experiencing severe interference use different PCIDs, while cells where interference is manageable use the same PCID to enable MIMO transmission, optimizing performance locally rather than applying a uniform approach network-wide
2Productivity
If carrier aggregation is used to improve data rates, then throughput is enhanced, but RLC entity splitting becomes complicated and signal reception is interfered with
Solution Approach 1:
Carrier aggregation is implemented by aggregating component carriers from multiple cells with different PCIDs. This segmentation approach allows the system to combine carriers while avoiding the complexity of RLC entity splitting that would arise from aggregating carriers within the same cell, simplifying the overall architecture
Solution Approach 2:
Cells with different PCIDs act as intermediaries in the carrier aggregation process. By using cells with distinct PCIDs as the basis for carrier aggregation, the system avoids direct interference issues and simplifies the RLC entity management that would be required if carriers from the same cell were aggregated
3Productivity
If the same PCID is used for multiple cells, then MIMO transmission is enabled across cells, but interference management becomes more challenging
Solution Approach 1:
The same PCID is allocated to specific cells where local conditions permit MIMO transmission without severe interference. Other cells use different PCIDs, creating a heterogeneous PCID allocation strategy that optimizes MIMO performance in suitable locations while managing interference in others
Solution Approach 2:
The PCID allocation and cell configuration are dynamically adjusted based on UE mobility and load conditions. The system can switch between using same-PCID and different-PCID cell configurations depending on the operational context, allowing flexible adaptation to changing network conditions
Data Source
AI summary
A cell configuration method of a base station in a mobile communication system supporting Carrier Aggregation (CA) which includes configuring a first cell consisting of at least two sectors formed with different antennas to a terminal, configuring a second cell consisting of at least two sectors formed with different antennas to the terminal, and communicating with the terminal through the first and second cells, wherein one of the first and second cells consists of sectors using same Physical Cell Identifier (PCID) and the other consists of sectors using different PCIDs.