VHBR RFID Receiver Symbol Synchronization via Pilot Symbols

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Solution Overview

Problem

Very high-speed RFID receivers face challenges in synchronizing with PSK symbols due to inter-symbol interference and complex signal processing requirements, particularly in achieving accurate symbol timing in high-bit-rate applications.

Innovation Solution

The proposed RFID receiver employs a digital quadrature demodulator with a symbol synchronization module, utilizing a pilot symbol sequence and sign correlation to synchronize with PSK symbols, and includes decimators to provide in-phase and quadrature components at the baud rate modulation, simplifying synchronization and reducing noise sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If phase modulation (PSK) and reduced symbol duration are used to achieve higher data rates, then throughput is improved, but inter-symbol interference increases due to band-pass coupling

Engineering Contradiction:

Improvedata rateVSAvoidsignal quality

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary equalization by inserting known pilot symbols before data transmission. These pilot symbols allow the receiver to pre-characterize the channel response and compensate for inter-symbol interference before actual data is transmitted, thereby maintaining signal quality at high data rates

Inventive Principle:

Principle #10Preliminary action

2Reliability

If digital quadrature demodulation is used to combat inter-symbol interference, then signal quality is improved, but device complexity increases due to required analog mixers

Engineering Contradiction:

Improvesignal qualityVSAvoidarchitecture complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the complex analog mixer components from the quadrature demodulation architecture. Instead, it uses direct digital synthesis and digital signal processing to achieve quadrature demodulation, thereby maintaining signal quality while dramatically reducing hardware complexity and making the system compatible with energy-constrained RFID receivers

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/analog mixer system with a digital signal processing system. By using digital multiplication and addition operations instead of analog mixing circuits, the system achieves the same quadrature demodulation function with significantly reduced complexity and better energy efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If decimators are used to provide baud rate sampling, then synchronization is improved, but noise sensitivity increases in the demodulation result

Engineering Contradiction:

Improvesymbol timing accuracyVSAvoidnoise sensitivity

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary filtering and averaging to the decimated samples before final demodulation. By preprocessing the samples to reduce noise content before the critical demodulation step, the system maintains accurate symbol timing while minimizing the impact of noise on the final result

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3116181B1RFID receiver with very high throughput

Publication Date: 2017.07.12 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

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AI summary

The invention relates to a VHBR RFID receiver comprising a quadrature digital demodulator, a baud-rate symbol synchronization module, and a PSK demodulator. The symbol synchronization module (200) receives the in-phase and quadrature samples from the demodulator and extracts the PSK symbol components at the baud rate by selecting a decimation instant. This synchronization is achieved by exploiting the specific structure of the transmission frame preamble in a VHBR RFID receiver.