Radio Base Station Adaptive Transmission Mode Selection
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Solution Overview
Problem
Conventional radio communication systems face challenges in accurately determining the transmission scheme for terminals near the cell edge, where interference is high, due to distorted cell areas and the need for massive feedback information, leading to inefficient use of frequency bands and reception characteristics.
Innovation Solution
Allocating specific frequency bands for single base station and CoMP transmissions, with reduced feedback information indicating reception quality, allowing the base station to accurately determine the transmission scheme based on measured SINR, thereby improving reception characteristics and reducing inter-cell interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the base station receives feedback information indicating reception quality of all frequency bands, then the transmission scheme can be accurately determined, but the amount of feedback information becomes excessively large
Solution Approach 1:
The system segments the frequency band into first frequency bands (for single base station transmission) and second frequency bands (for CoMP transmission). The terminal measures and feeds back reception quality separately for each segment, reducing the total feedback amount while maintaining accurate transmission scheme determination through selective feedback based on band type.
Solution Approach 2:
The invention extracts only the necessary reception quality information for specific frequency bands used for single base station transmission from the complete set of all frequency bands. By taking out only the relevant bands for feedback, the system reduces feedback overhead while preserving the ability to accurately determine transmission schemes.
2Ease of operation
If the base station uses distorted cell area information to determine transmission scheme, then the determination process becomes complex, but the reception quality of cell edge terminals cannot be improved
Solution Approach 1:
The invention replaces the mechanical/geographical approach of using cell area distance and distorted cell shape information with a signal-quality-based approach. The terminal measures actual reception quality (SINR) of reference signals directly, and the base station determines transmission schemes based on these measured values, eliminating complexity from geographical calculations while improving reliability for cell edge terminals.
Solution Approach 2:
The system changes the determination parameter from geographical position (distance from cell center, cell area shape) to signal quality parameter (SINR of reference signal). This parameter change simplifies the determination process by using direct measurements rather than complex geographical calculations, while simultaneously improving reception quality assessment for cell edge terminals.
3Quantity of substance
If the system uses one-cell repetition use to maximize frequency bandwidth, then the frequency bandwidth usable in one cell is maximized, but inter-cell interference increases significantly
Solution Approach 1:
The system applies different transmission qualities/schemes to different frequency bands: single base station transmission for first frequency bands and coordinated multipoint transmission for second frequency bands. This local differentiation allows the system to maintain high frequency bandwidth utilization while reducing inter-cell interference through selective application of CoMP transmission where needed.
Solution Approach 2:
The system dynamically selects transmission schemes based on measured reception quality. The base station determines whether to use single base station transmission or CoMP transmission for each terminal based on actual SINR measurements, allowing flexible adaptation that maximizes frequency bandwidth usage while minimizing inter-cell interference through condition-based scheme selection.
Data Source
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AI summary
A radio base station apparatus wherein even when a single-base-station transmission and a plural-base-station cooperative transmission are implemented at the same time, the terminal-to-base-station feedback information amount and the ICI can be reduced, thereby improving the reception characteristic of a terminal existing in the vicinity of a cell edge. A base station (100) uses a first transmission mode, in which only the base station implements a signal transmission, and a second transmission mode, in which the base station implements a cooperative signal transmission together with another radio base station apparatus, to communicate with one or more radio terminal apparatuses. A setting unit (103) sets, as a particular frequency band the reception quality of which is to be measured, one of first and second frequency bands that are parts of a band used for communications with the terminals. A deciding unit (101) decides, as the transmission mode for the terminals, one of the first and second transmissions on the basis of the reception quality of the particular frequency band.