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Method and device for automatic gain control in wireless communication system

一种自动增益控制、增益变化的技术，应用在增益控制、放大的控制、传输的控制/均衡等方向

Inactive Publication Date: 2008-06-04
ADAPTIX
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the feedback loop has a time delay, if the power regulation is done too quickly, the feedback loop can become an oscillator which can create a ping-pang effect on the power level

Method used

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  • Method and device for automatic gain control in wireless communication system
  • Method and device for automatic gain control in wireless communication system
  • Method and device for automatic gain control in wireless communication system

Examples

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Embodiment Construction

[0011] Figure 1 shows a prior art AGC circuit 10 using a conventional implementation. AGC 10 controls the gain applied to the signal arriving at input 101 to maintain a target power level at output 102 . An analog-to-digital converter (ADC) 104 digitizes the amplified signal and provides the digital signal to an output 102 and a power measurement unit 105 . The measured power is then compared to the target power level by the target power comparison subsystem 106 . The result of this comparison is then fed back to the variable amplifier 103 as a gain adjustment signal. Usually, the gain can be adjusted frame by frame.

[0012] figure 2 An AGC circuit 20 according to an embodiment of the invention is shown. AGC 20 controls the gain applied to the signal arriving at input 101 to maintain a target power level at output 102 . Specifically, the gain of the variable amplifier 103 is adjusted according to the feedback from the adaptive power comparison subsystem 201 . An optiona...

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Abstract

The invention provides an automatic gain control (AGC) system and a method which has an adaptive reference and an adaptive threshold value. The adaptive reference allows the target power to be adjusted according to variation of the operation parameter and condition, such as the modulation mode changing for sustaining the performance with different Signal to Noise Ratio (SNR), while the adaptive threshold value allows a fast AGC response and reduces the delayed and potential impact. The invention has the advantage that the AGC level can be changed between the symbol prefix and the symbol suffix, but can not be changed during the data part of the signal. The embodiment provided allows the AGC to be changed according to each symbol in OFDM, OFDMA and TDD systems.

Description

technical field [0001] The present invention relates generally to wireless communications and, more particularly, to automatic gain control (AGC) for wireless systems. Background technique [0002] For symbol-based wireless systems, such as Orthogonal Frequency Division Multiplexing (OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), and Time Division Duplex (TDD) systems with frame-based AGC, fast fading channels can Given the dynamic range conundrum. The problem exists because the signal strength can fluctuate significantly during a frame containing many symbols, resulting in different signal-to-noise ratios (SNR) among the symbols. A further compounding challenge is that there are different SNR requirements for the various commonly used modulation schemes. [0003] For example, 16 quadrature amplitude modulation (16 QAM) has worse bit error rate (BER) performance than quadrature phase shift keying (QPSK) for a given SNR. In order to compensate for this diffe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B7/005H04L27/26H04B7/26
CPCH03G3/3052H04L1/0003H03G3/3036H04L27/3809
Inventor 王海涛
Owner ADAPTIX
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