Small Cell Reference Signal Coverage and Interference Management
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Solution Overview
Problem
In radio communication systems where macro cells use low frequency bands and small cells use high frequency bands, it is challenging to expand the coverage and improve the received quality of reference signals due to significant path loss, which can lead to interference between small cells when increasing transmission power.
Innovation Solution
A radio base station that transmits reference signals with a narrower bandwidth and greater power in periods without beamforming, allocating them to specific bands associated with each small cell, to enhance coverage and reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the transmission power of reference signals is increased to expand coverage, then the coverage of reference signals is improved, but interference between small cells increases and received quality decreases
Solution Approach 1:
The patent divides the frequency band into multiple sub-bands and allocates different sub-bands to different small cells for reference signal transmission. This segmentation allows multiple small cells to transmit reference signals simultaneously without interfering with each other, as each cell uses a dedicated frequency sub-band. The base station assigns specific frequency resources to each small cell based on its location and coverage requirements.
Solution Approach 2:
The patent applies different transmission parameters to different small cells based on their specific characteristics and locations. Each small cell is assigned appropriate transmission power, bandwidth, and frequency resources tailored to its local environment and coverage needs. This localized optimization allows each cell to expand its coverage effectively without causing excessive interference to neighboring cells.
2Area of stationary object
If the transmission power of reference signals is increased to expand coverage, then the coverage of reference signals is improved, but the received quality of reference signals in user terminals decreases
Solution Approach 1:
By segmenting the frequency band into dedicated sub-bands for each small cell, the patent eliminates frequency-domain interference between cells. This ensures that reference signals from different small cells do not overlap or interfere with each other, maintaining high received quality for user terminals while still enabling expanded coverage through appropriate power control.
Solution Approach 2:
The patent dynamically adjusts transmission parameters including power, bandwidth, and frequency allocation based on the operational state and coverage requirements of each small cell. The base station monitors signal conditions and modifies transmission parameters to optimize both coverage expansion and received quality, preventing degradation due to excessive power or interference.
Data Source
AI summary
The present invention is designed to expand the coverage of reference signals in small cells that are arranged to overlap a macro cell, and, furthermore, reduce the interference between the small cells and improve the received quality of the reference signals in user terminals. The radio communication method of the present invention provides a radio communication method in a radio base station forming a small cell that is placed to overlap a macro cell, and includes the steps of generating a reference signal for measuring received quality, in a first transmission period in which beamforming is not executed, transmitting the reference signal in a narrower transmission bandwidth and with greater transmission power than in a second transmission period in which beamforming is executed, and allocating the reference signal to a band associated with information that is specific to each radio base station forming a small cell, and transmitting the reference signal.