Radio Base Station Power Control for Femto Cell Handovers
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Solution Overview
Problem
Handovers between cells with different coverage areas often fail, particularly when a femto base station attempts to move a radio communication terminal from a wider source cell to a narrower destination cell, leading to communication failures and inefficient resource utilization.
Innovation Solution
A radio base station that controls transmission power based on quality metrics for both LTE and 3G frequency bands to match the coverage areas of cells formed by different frequency bands, ensuring successful handovers by adjusting power levels to align the coverage areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a femto base station uses different frequency bands for LTE and 3G systems, then interconnectivity between systems is achieved, but the coverage areas of the two cells become mismatched leading to handover failures
Solution Approach 1:
The patent dynamically adjusts transmission power parameters for different frequency bands (LTE and 3G) to align coverage areas. The base station monitors handover success rates and modifies power settings accordingly, changing the physical parameter of transmission power to resolve the coverage mismatch caused by using different frequency bands
Solution Approach 2:
The system implements a feedback mechanism where handover failure information is collected and analyzed. Based on this feedback, the base station automatically adjusts transmission power levels for different cells to optimize coverage alignment and prevent future handover failures
2Area of stationary object
If transmission power is adjusted according to propagation loss from macro base station, then femto cell coverage is optimized, but coverage area mismatch with macro cell increases
Solution Approach 1:
The patent modifies the transmission power parameter dynamically based on observed handover performance. Instead of using fixed propagation loss-based power adjustment, the system adapts power levels to achieve coverage alignment between macro and femto cells, resolving the contradiction between optimizing femto coverage and maintaining handover reliability
3Adaptability or versatility
If handover is performed from LTE cell to 3G cell, then voice call functionality is maintained, but communication data rate decreases
Solution Approach 1:
The patent performs preliminary coverage alignment by adjusting transmission powers before handovers occur. By pre-configuring optimal power levels that align LTE and 3G cell coverages, the system enables seamless handovers that maintain both voice call functionality and high data rates, preventing the need to fall back to lower-speed networks
Data Source
AI summary
When one base station forms a plurality of cells that use different frequency bands, a handover caused by movement between cells can be successfully performed with a high probability. A radio base station (100) adapted to communicate with a radio communication terminal, comprising: a communication unit which performs a first communication with the radio communication terminal (110) by using a first frequency, wherein the communication unit performs a second communication with the communication terminal(120) by using a second frequency that is different from the first frequency; and a controller(104) which performs a control, of at least one of a first power of the first communication and a second power of the second communication, based on a first power-related quality of the first communication and a second power-related quality of the second communication.