Base Station Guard Time Adjustment for Frequency Sensing
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Solution Overview
Problem
In radio communication systems, a short guard time set when the terminal and base station are close results in insufficient time for measuring reception levels, leading to deteriorated frequency sensing accuracy.
Innovation Solution
A base station configuration that includes a receiving section, reception level measurement, guard-time-length setting, frequency band selection, Ack/Nack generation, and control signal transmission, allowing for accurate frequency sensing by adjusting guard time length and selecting suitable frequency bands while maintaining transmission rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a short guard time is set when the distance between terminal and base station is short, then transmission rate increases, but frequency sensing accuracy deteriorates due to insufficient measurement time
Solution Approach 1:
The base station performs frequency band selection and reception level measurement during the guard time period before the uplink transmission begins. By conducting the frequency sensing measurement in advance during the guard interval, the system ensures accurate frequency band selection without compromising the subsequent uplink transmission rate, as the measurement is completed before the data transmission phase starts.
Solution Approach 2:
The system dynamically adjusts the guard time length based on the distance between terminal and base station. When the distance is short, a shorter guard time is set to maintain high transmission rate, while still allocating sufficient time within that shorter guard period to complete the reception level measurement and frequency band selection, thus adapting the measurement duration to the actual transmission requirements.
2Productivity
If the guard time is set to be as short as possible to increase transmission rate, then productivity improves, but the time available for measuring reception level decreases
Solution Approach 1:
The reception level measurement and frequency band selection are performed as preliminary actions during the guard time period before the uplink data transmission begins. This ensures that the measurement is completed in advance, allowing the system to use the full uplink transmission period for data transfer without sacrificing measurement accuracy, thus maximizing the effective transmission rate.
Solution Approach 2:
The system changes the parameter of guard time length dynamically based on transmission requirements. By adjusting the guard time to be as short as possible while still sufficient for measurement, the system optimizes the balance between measurement time and transmission rate, ensuring that the guard time parameter is adapted to meet both measurement and transmission needs efficiently.
Data Source
AI summary
A base station is provided that performs time-division duplex radio communication with a terminal, using part of a frequency band shared with another system. The base station includes a receiver that receives an uplink signal from the terminal for each frequency band in use, and a guard-time-length setter that sets a length of a guard time. The base station also includes a reception level measurer, which measures a reception level of the uplink signal and a reception level of the guard time having a predetermined length, and a frequency band selector, which selects a frequency band in which the reception level of the guard time is not greater than a first threshold. The base station further includes a control signal generator that generates a control signal, and a transmitter that transmits a downlink signal, including the control signal, to the terminal for the frequency band in use.