Downlink Cooperative Component Carriers for Cell-Edge Performance
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Solution Overview
Problem
Current cellular systems face challenges in providing uniform user experience and efficient spectrum utilization at cell-edges due to interference from other cells, especially when frequency reuse factor is one, and the support of multiple component carriers is limited to a single serving evolved Node-B, preventing simultaneous connections with different eNBs.
Innovation Solution
A wireless communication network allows a WTRU to establish connections with multiple sites via different downlink component carriers, manipulating transmit power to create coverage overlap and enabling handovers between CC frequencies, thereby improving cell-edge performance.
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 frequency spectrum into multiple component carriers (CCs) that can be independently allocated to different cells. This allows frequency reuse factor of one to be maintained across the aggregate spectrum while individual CCs can be assigned to specific cells to avoid interference at cell edges, thereby resolving the contradiction between spectrum utilization and cell-edge performance
Solution Approach 2:
The patent introduces a new dimension of carrier aggregation, allowing users to connect to multiple component carriers from different cells simultaneously. This multi-dimensional approach enables the system to maintain frequency reuse factor of one while providing diverse paths for data transmission, improving cell-edge performance without sacrificing spectrum efficiency
2Device complexity
If multiple component carriers are supported on a single serving eNB, then device complexity is reduced, but adaptability deteriorates as simultaneous connections with different eNBs are prevented
Solution Approach 1:
The patent implements a universal carrier aggregation framework where the user equipment can simultaneously aggregate multiple component carriers from different eNBs. This multi-functional capability allows the device to adapt to various network configurations and maintain connections with multiple eNBs, thereby improving adaptability while managing device complexity through standardized protocols
3Area of stationary object
If transmit power is increased to expand coverage, then coverage area is improved, but interference to other cells increases
Solution Approach 1:
The patent applies local quality by assigning different component carriers to different cells with optimized transmit power levels for each local area. This allows each cell to expand its coverage on specific carriers without causing excessive interference to neighboring cells on those same carriers, as the power is optimized locally for each cell-carrier combination
Solution Approach 2:
The patent creates multiple copies of the same frequency spectrum across different component carriers, allowing cells to use the same frequencies without interfering with each other. By distributing traffic across multiple CC copies, the system can expand coverage on each carrier at optimized power levels while avoiding the interference that would result from increasing power on a single carrier
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.