Adaptive Pre-equalizer for NFC Inter-symbol Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Near field communication (NFC) devices face challenges in achieving high data rates while maintaining energy efficiency, as increased data rates lead to inter-symbol interference (ISI) due to the antenna resonator, which complicates the design of energy-efficient antenna structures for NFC applications.
Innovation Solution
A digital adaptive pre-equalizer is implemented to reuse the receiver structure for feedback, adjusting the coefficients of a finite impulse response (FIR) filter to create a frequency-independent transfer function, pre-equalizing ISI under varying channel conditions, and using adaptive tuning to retune the transmitter antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the antenna resonator is tuned to the carrier frequency for efficient power transfer, then energy efficiency is improved, but inter-symbol interference increases at higher data rates
Solution Approach 1:
The patent implements a feedback mechanism where the received signal is processed through the equalizer and the error signal is fed back to adjust the equalizer coefficients. This closed-loop feedback allows the system to continuously adapt to channel conditions and compensate for ISI while maintaining resonant tuning for energy efficiency.
Solution Approach 2:
The patent dynamically adjusts the equalizer coefficients as parameters to compensate for the harmful ISI effects. By changing the equalizer parameters in response to feedback from the received signal, the system maintains optimal performance at high data rates while keeping the antenna resonator tuned for energy efficiency.
2Productivity
If the data rate is increased to improve productivity, then data transmission speed is improved, but inter-symbol interference increases due to the antenna resonator
Solution Approach 1:
The patent applies pre-equalization by adjusting the equalizer coefficients before the signal is transmitted through the resonant antenna. This preliminary action compensates for the ISI that will occur during transmission, enabling high data rates to be achieved without the harmful effects of inter-symbol interference.
Solution Approach 2:
The feedback mechanism allows the equalizer to adapt its coefficients based on the actual channel conditions experienced during high-speed transmission. This feedback enables the system to maintain optimal equalization performance as data rates increase, preventing ISI from degrading signal quality.
3Speed
If a resistor is added to provide dampening and increase transmit bandwidth, then bandwidth is improved, but energy efficiency decreases
Solution Approach 1:
The patent replaces the need for resistive dampening (which dissipates energy) with a digital equalization system. Instead of using a resistor to broaden bandwidth, the system uses signal processing through the equalizer to compensate for bandwidth limitations and ISI effects, thereby maintaining energy efficiency while achieving the required bandwidth for high data rates.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces ISI, improves signal quality, and maintains energy efficiency by continuously adapting to channel conditions, enabling higher data rates in NFC applications without compromising power efficiency.
Implementation Method 1
The antenna of a PCD consists of an inductor Lr that emits the magnetic field that is used both to power the (passive) PICC, and to carry the data during transmission via mutual inductance M
Implementation Method 2
the PCD's antenna resonator can be tuned to the carrier frequency used in transmission
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Equalization circuits and methods are implemented for a variety of applications. According to one such application, a transmitting device wirelessly communicates using an antenna. The device has a transmission circuit that is configured and arranged to transmit a first wireless signal using magnetic coupling between the antenna and a remote device, the coupling occurring over a wireless medium. A receiver circuit of the transmitting device is configured and arranged to receive a second wireless signal that is from the antenna and that represents the first wireless signal as modified by the coupling occurring over the wireless medium. An error circuit of the device is configured and arranged to generate an error signal by comparing the first wireless signal to the second wireless signal. An equalizer circuit of the device is configured and arranged to pre-code the first wireless signal with coding that compensates for inter-symbol interference by compensating for the error signal.