Received Power Estimation Using Sensor Station Correction

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Solution Overview

Problem

Existing methods for estimating received power in cognitive radio systems face challenges due to measurement errors, particularly when the secondary signal's reception level is lower than the primary signal's, leading to increased margins in allowed transmission power, which can limit the secondary system's transmission capacity.

Innovation Solution

A received power estimation device and method that compensates for measurement errors by using a sensor station located near the secondary transmitter to measure the secondary signal's power, allowing for more accurate path loss estimation and reduced margins in allowed transmission power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If path loss estimation is performed using propagation models (e.g., Okumura-Hata model), then allowed transmission power can be determined, but measurement precision deteriorates due to errors from planimetric features, topography, and shadowing

Engineering Contradiction:

Improveallowed transmission powerVSAvoidpath loss estimation accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

A sensor station is introduced as an intermediary device to measure the actual received power of the secondary signal at a location near the primary receiver. This measured value serves as a mediator to correct the path loss estimation, compensating for errors caused by planimetric features, topography, and shadowing without requiring complex environmental data processing

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses feedback from the sensor station measurements to correct the path loss estimation. The measured received power at the sensor station is compared with the estimated received power, and the difference is used to adjust the path loss calculation, thereby improving accuracy in determining allowed transmission power

Inventive Principle:

Principle #23Feedback

2Reliability

If a large margin is added to compensate for CIR estimation errors, then reliability of primary system reception is improved, but allowed transmission power decreases

Engineering Contradiction:

Improveprimary system reception qualityVSAvoidsecondary system transmission capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent replaces the conventional approach of using propagation models with a measurement-based approach. Instead of relying on theoretical path loss calculations that require large margins for error compensation, the system uses actual measurements from a sensor station to determine the true path loss, thereby reducing the need for conservative margin additions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the secondary signal's reception level is kept lower than the primary signal to ensure primary system quality, then primary system reliability is improved, but measurement precision of secondary signal power deteriorates

Engineering Contradiction:

Improveprimary system reception qualityVSAvoidsecondary signal power measurement

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The sensor station acts as an intermediary that enables accurate measurement of the secondary signal power even when the signal level is low. By placing the sensor station near the primary receiver and using it to measure the secondary signal, the system can accurately determine the interference level without requiring the secondary signal to be at high power, thus maintaining primary system quality while enabling precise measurements

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9386537B2Received power estimation device, received power estimate method, program, sensor station, and radio system

Publication Date: 2016.07.05 NEC CORP

AI summary

The present invention is a device which, when a second wireless system shares the use of a frequency which is allocated to a first wireless system, estimates receiving power when a second wireless signal which is transmitted from a transmission station of the second wireless system is received at a receiving station of the first wireless system. The receiving power estimation device comprises a correction means for correcting a receiving power estimate value of the second wireless signal at the first wireless system receiving station which is computed using an estimate value of path loss from the second wireless system transmission station to the first wireless system receiving station, said correction using a receiving power measurement value of the second wireless signal which is measured in a transmission station periphery sensor station which is a sensor station which is located in the periphery of the second wireless system transmission station.