Discrete-Time Receiver Filtering for Low-Power Multi-Carrier Demodulation

Solution Overview

Problem

Existing digital RF technologies face challenges in handling complex modulated signals like multi-ary data, leading to increased power and area overhead, making it difficult to achieve low power consumption and low cost in applications such as sensor net communication.

Innovation Solution

A digital radio receiver apparatus comprising a sampler circuit that converts continuous time signals to discrete time signals, a discrete time filter that attenuates unwanted subcarrier frequency components, and a demodulation unit that completes demodulation within one data symbol reception period, using a moving average filter and adaptive frequency switching to reduce chip area and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If analog-to-digital conversion and digital signal processing are used to handle complex modulated signals, then measurement precision and reliability are improved, but use of energy and device complexity increase

Engineering Contradiction:

Improvesignal processing precisionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes unnecessary signal processing steps from the conventional demodulation chain. By using a correlation-based detector that directly correlates the received signal with local carrier signals, the system eliminates the need for complex analog-to-digital conversion and extensive digital signal processing, thereby reducing power consumption while maintaining demodulation accuracy for complex modulated signals.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses local carrier signal copies generated by a carrier wave generator to perform correlation detection. Instead of processing the raw modulated signal through multiple stages, the system creates local copies of carrier waves at different frequencies and phases, correlates them with the received signal, and determines modulation type based on correlation results, significantly reducing computational complexity and power consumption.

Inventive Principle:

Principle #26Copying

2Measurement precision

If analog-to-digital conversion and digital signal processing are used to handle complex modulated signals, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvesignal processing precisionVSAvoidchip area

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes unnecessary signal processing steps from the conventional demodulation chain. By using a correlation-based detector that directly correlates the received signal with local carrier signals, the system eliminates the need for complex analog-to-digital conversion and extensive digital signal processing, thereby reducing power consumption while maintaining demodulation accuracy for complex modulated signals.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses local carrier signal copies generated by a carrier wave generator to perform correlation detection. Instead of processing the raw modulated signal through multiple stages, the system creates local copies of carrier waves at different frequencies and phases, correlates them with the received signal, and determines modulation type based on correlation results, significantly reducing computational complexity and power consumption.

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If conventional demodulation methods are used for multiple subcarriers, then adaptability is improved, but use of energy and device complexity increase

Engineering Contradiction:

Improvemulti-carrier demodulation capabilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the multi-carrier signal processing into independent correlation operations for each subcarrier frequency. The correlation detector separately correlates the received signal with local carrier signals at different frequencies (f1, f2, ..., fN) and phases, allowing the system to handle multiple modulation types across multiple subcarriers simultaneously without requiring a single complex processing chain, thereby reducing overall power consumption while maintaining versatility.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8345800B2Receiver apparatus and reception method

Publication Date: 2013.01.01 NEC CORP

AI summary

A receiver includes a sample and hold circuit that receives a signal (continuous time signal) that has been subject to frequency division multiplexing modulation, converts the signal to a discrete time signal, and outputs the discrete time signal, a discrete time filter that receives the signal output from the sample and hold circuit and attenuates a frequency component of a subcarrier different from a specified subcarrier, and a demodulation unit that extracts a digital baseband from a signal that has passed through the discrete time filter to complete a demodulation operation within one data symbol reception period.