Uplink Power Control via Multi-Base Station Path Loss Coordination
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Solution Overview
Problem
In mobile communication systems where multiple radio base stations receive uplink signals from a radio terminal, traditional power control methods based on path loss between a single base station and the terminal can lead to excessive transmission power, particularly when a radio terminal is isolated from a macro base station and positioned near a pico base station.
Innovation Solution
Implementing a system where each radio base station acquires and notifies the path loss to other base stations, allowing at least one base station to notify the terminal of the smallest or a calculated path loss for transmission power control, ensuring appropriate power adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If transmission power control is performed based on path loss between a single radio base station and the radio terminal, then the control method is simple, but the transmission power becomes excessive when the terminal is positioned near a different base station
Solution Approach 1:
The patent combines path loss information from multiple radio base stations (macro base station and pico base station) to determine the transmission power control parameter. Instead of using path loss from a single base station, the system integrates measurements from multiple base stations to select the appropriate path loss value, thereby preventing excessive transmission power while maintaining reasonable control complexity.
2Ease of operation
If transmission power control uses path loss from the macro base station, then the control is straightforward, but it causes excessive power consumption when the terminal is isolated from the macro base station and near the pico base station
Solution Approach 1:
The system dynamically selects which base station's path loss to use for transmission power control based on the terminal's current position and signal conditions. The terminal measures path loss to multiple base stations and the network dynamically determines the appropriate path loss value to use, allowing the power control parameter to adapt to changing conditions rather than being fixed to a single base station.
Solution Approach 2:
The patent changes the parameter used for transmission power control from a fixed base station path loss to a selectable path loss value that can be changed based on terminal position. The system modifies which path loss parameter (macro base station or pico base station) is applied for power control, enabling optimization of transmission power according to the terminal's location and signal environment.
3Reliability
If multiple radio base stations coordinate to receive uplink signals, then signal reception quality improves, but determining the appropriate path loss for power control becomes complex
Solution Approach 1:
The patent extracts only the necessary path loss information from multiple base stations for power control purposes, rather than coordinating all aspects of signal processing. The system measures and exchanges only the relevant path loss parameters between base stations and terminal, simplifying the coordination complexity while still benefiting from multiple base station involvement in signal reception.
Data Source
AI summary
A mobile communication system of an embodiment is a system in which a plurality of radio base stations receive an uplink signal transmitted from a radio terminal coordinated with one another. Each of the plurality of radio base stations comprises: an acquisition unit that acquires a path loss between the radio terminal and the radio base station; and an interface that notifies the path loss acquired by the acquisition unit to another radio base station. At least one the radio base station of the plurality of radio base stations includes a notification unit that notifies the radio terminal of the path loss used in the transmission power control of the uplink signal, in accordance with the path losses between each of the plurality of radio base stations and the radio terminal.