Downlink Cooperative Component Carriers for Cell-Edge Performance
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Solution Overview
Problem
Current cellular systems face challenges in providing a uniform user experience due to interference at the cell-edge, especially when frequency reuse is one, and the support for carrier aggregation is limited to a single serving evolved Node-B, preventing simultaneous connections with different cells.
Innovation Solution
A wireless communication network and method that allows a WTRU to connect with multiple sites via different downlink component carriers, manipulating transmit power to create coverage overlap and enable handovers between frequencies, thereby improving throughput at the cell-edge by accessing multiple sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If frequency reuse factor is one, then spectrum utilization is improved, but cell-edge user performance deteriorates due to interference from other cells
Solution Approach 1:
The patent segments the cell coverage area by introducing multiple component carriers with different coverage characteristics. Each component carrier serves a specific geographic region, dividing the overall cell into multiple coverage zones. This allows frequency reuse factor of one to be maintained while reducing interference at cell edges through carrier-specific coverage segmentation.
Solution Approach 2:
Different component carriers are configured with different transmit powers to create localized coverage optimization. The first component carrier uses higher transmit power for broader coverage, while the second component carrier uses lower transmit power for targeted cell-edge coverage. This local quality differentiation improves cell-edge performance without sacrificing overall spectrum utilization.
2Reliability
If different cells use different sets of component carriers, then cell-edge interference is reduced, but effective frequency reuse factor becomes greater than one reducing spectrum utilization
Solution Approach 1:
The patent merges multiple component carriers from different cells into a unified carrier aggregation framework. The WTRU simultaneously receives data on the first component carrier from a first cell and on the second component carrier from a second cell, combining resources from multiple cells while maintaining frequency reuse factor of one to preserve spectrum utilization efficiency.
3Device complexity
If carrier aggregation is limited to one serving evolved Node-B, then system complexity is reduced, but the ability to maintain simultaneous data connection with different cells is lost
Solution Approach 1:
The patent extends carrier aggregation functionality to support multiple serving evolved Node-Bs simultaneously. The WTRU is configured to perform carrier aggregation across multiple cells, enabling it to maintain data connections with different cells at the same time. This multi-functional capability allows the system to handle both single-cell and multi-cell scenarios within a unified framework.
Data Source
AI summary
A wireless transmit/receive unit (WTRU) receives first timing advances and first power control commands from a first eNodeB and second timing advances and second power control commands from a second eNodeB and transmits, to the first eNodeB, a first physical uplink control channel using a first uplink component carrier. The first physical uplink control channel has a first timing adjusted by the first timing advances but not by the second timing advances and a first power level adjusted by the first power control commands but not by the second power control commands. The WTRU transmits a second physical uplink control channel using a second uplink component carrier. The second physical uplink control channel has a second timing adjusted by the second timing advances but not by the first timing advances and a second power level adjusted by the second power control commands but not by the first power control commands.