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Qam receiver

A technology for receivers and receiving signal vectors, applied in the field of telecommunication systems, can solve problems such as dependence and complex decision-making circuits, and achieve the effect of simple implementation and significant energy gain

Inactive Publication Date: 2009-09-09
SYMBOL TECH INC
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Furthermore, many existing implementations rely on relatively complex decision circuits

Method used

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example 1

[0031] B. Example 16-QAM constellation located at a square array node

[0032] A constellation diagram is a representation of digital modulation in the complex plane. The real and imaginary axes on the complex plane are often referred to as the event or I axis and the quadrature or Q axis. The points on the constellation diagram are called constellation points. Constellation diagrams enable intuitive visualization of modulation processing. A received symbol can be placed as an arbitrary point in the I-Q plane, and its decoded binary value is equal to the value of the constellation point closest to its position.

[0033] figure 2 An example 16-QAM constellation 200 at the nodes of a square array 210 is shown. In this case, the bits are grouped into groups of four. Thus, in the signal space of the 16-QAM constellation diagram, there are 16 possible binary values ​​of the 4-bit / symbol hexadecimal data signal corresponding to the 16 constellation points with indices 1, 2, .....

example 16-Q

[0061] b. Example 16-QAM Adaptive Receiver

[0062] In an embodiment, the adaptive receiver of the present invention is based on coherent signal processing, which has been shown to provide significant energy gains over conventional non-coherent processing of multi-position QAM modulated signals. Coherent signal processing is based on carrier recovery by successive phase and amplitude adjustments, including initial phase and amplitude estimation during the preamble and phase and amplitude tracking during data transmission.

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Abstract

The present invention provides methods and apparatuses for demodulation and decoding of backscattered 16-QAM RFID tag signals, represented by their in-phase and quadrature components at the output of the demodulator in the receiver portion of a reader interrogator. In a communication channel with fast changing parameters, a reader receiver adaptively and coherently corrects the in-phase and quadrature-phase components of a signal received from a tag by tracking the phase and amplitude of the signal based on a decision-feedback. A reference signal is used to correct the signal components, where the coordinates of the reference signal is updated by a tracking and an averaging algorithm. A simple implementation of the receiver in a digital signal processing environment is enabled.

Description

technical field [0001] The present invention relates to telecommunication systems, including wireless telecommunication systems enabling data transmission via radio channels. More particularly, the present invention relates to radio frequency identification (RFID) systems and methods for data transmission between RFID tags and RFID reader interrogators. Background technique [0002] Wireless communication technology has shown a continuing strong trend to use multi-position phase-shift keying (PSK) and quadrature amplitude modulation (QAM) techniques. Most wireless systems are based on modulation techniques such as Bi-Phase Shift Keying (BPSK), Quadrature Phase-Shift Keying (QPSK), 16-QAM and 64-QAM. These modulation techniques are standardized for use in current and future mobile and fixed wireless systems, including IEEE 802.16 standard systems for fixed, portable, and mobile broadband wireless access. The most popular technologies are QPSK and 16-QAM. The 16-QAM modulat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/38
CPCH04L27/3836
Inventor Y·奥库尼夫
Owner SYMBOL TECH INC
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