KR100277127B1 - Frequency Error Coupler for Multicarrier Receive Signals in Wireless Communication Systems - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs

The present invention relates to a receiving end of a multi-carrier wireless communication system, and more particularly to a frequency control apparatus of the receiving end.

I. The technical problem that the invention is trying to solve

Provided is a device for combining carrier-specific frequency errors of a multicarrier received signal.

All. Summary of the Solution of the Invention

The carrier outputs a reference clock generator that combines the frequency error of each carrier of the multicarrier received signal to correct the frequency error.

la. Important uses of the invention

The frequency error of the multicarrier received signal is corrected by combining the carrier frequency error.

Description

Frequency Error Coupler for Multicarrier Receive Signals in Wireless Communication Systems

The present invention relates to a receiving end of a multi-carrier wireless communication system, and more particularly to a frequency control apparatus of the receiving end.

In order to demodulate the received signal, the receiving end of the wireless communication system generates a frequency equal to a carrier frequency output from the transmitting end and performs frequency synchronization to down convert the received signal. On the other hand, an error between the carrier frequency of the transmitting end and the frequency of the receiving end causes attenuation of the received signal, thereby degrading data demodulation performance.

In general, the receiving end converts a received signal in a radio frequency band through several steps and converts the received signal into a base band signal. At this time, the received signal of the radio frequency band is passed through a frequency mixer (Mixer) is converted into an intermediate frequency (Intermediate Frequency) signal. In the process, a phase control loop outputs a corresponding frequency control signal to the frequency mixer according to a reference frequency control signal output from a reference clock generator VCTCXO, which will be described later.

The receiving end samples the baseband signal through an analog-to-digital converter, and performs demodulation of the signal. At this time, the frequency error detector provided at the receiving end detects a rate of change of phase with respect to time of the demodulated signal input for each multipath and outputs frequency errors for each path. Thereafter, the frequency error combiner discriminates and combines the path-specific frequency errors to output a carrier frequency error. The carrier frequency error is converted into a voltage control signal via a digital-to-analog converter. At this time, the reference clock generator inputs the voltage control signal and outputs a corresponding reference frequency control signal to control the phase control loop.

As described above, the receiving end of the wireless communication system detects a frequency error from the demodulated signal, and feeds back the frequency error information, that is, controls the reference clock generator to adjust frequency synchronization. Calibrate

On the other hand, the mobile communication system of the code division multiple access method has been developed from the IS-95 standard focused on the transmission / reception of voice signals, and has been discussed as the IMT-2000 standard capable of transmitting high speed data as well as voice. The IMT-2000 standard aims to provide services such as high quality voice, moving picture, and Internet search. In addition, as a test system for the IMT-2000 standard, a multi-carrier method for transmitting information to be transmitted to a plurality of carriers has been proposed. In other words, the multicarrier method modulates and transmits information signals that are directly sequence spread by the same PN sequence to a plurality of different carriers.

The transmitting end of a multicarrier code division multiple access system may use a method of converting an information signal into a plurality of parallel signals and multiplying the converted signal by multiplying the PN sequence. In this case, the transmitter performs an operation of modulating by multiplying the plurality of spread signals by different carriers. Meanwhile, the receiving end of the system may perform an operation of combining the frequency error of the received receiving signals for each carrier for frequency synchronization with a plurality of carrier receiving signals transmitted from the transmitting end. The combined frequency error is converted into a corresponding voltage control signal and output to the aforementioned reference clock generator. As a result, the reference clock generator outputs a frequency control signal to a plurality of phase control loops for stepping down each carrier received signal, thereby correcting a frequency error for each carrier frequency signal.

However, as described above, since the conventional code division multiple access mobile communication system transmits a signal using a single carrier method, the receiver does not perform an operation of combining the frequency error of the received signal for each carrier.

Accordingly, an object of the present invention is to provide an apparatus for combining the carrier-specific frequency error of a multicarrier received signal.

According to an aspect of the present invention, there is provided a device for combining carrier-specific frequency errors of multicarrier received signals in a wireless communication system, comprising: a plurality of path frequency error detectors for detecting path-specific frequency errors of a corresponding received carrier signal; A plurality of frequency error discriminators for controlling the output of the frequency errors for each path of the plurality of path frequency error detectors by determining whether the path-specific intensities of the corresponding carrier received signals are greater than a set level, and outputting the plurality of path frequency error detectors; A frequency error combiner for combining a frequency error for each path, and outputting a carrier frequency error of a corresponding carrier reception signal combined for each path if any one of the path-specific strengths of the received signal is greater than a set level. Error detector and the frequency error detector Frequency error detectors having the same configuration and outputting carrier frequency errors of the corresponding carrier reception signals, respectively, and carrier frequency error combiners outputting multicarrier frequency errors by combining carrier frequency errors output from the frequency error detectors, respectively. Characterized in that made.

1 is a diagram illustrating a multicarrier frequency error combiner according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a diagram illustrating a multicarrier frequency error combiner according to an embodiment of the present invention.

The first carrier frequency error detector 110 to the Nth carrier frequency error detector N10 input the first carrier signal to the Nth carrier signal, respectively. The first carrier signal to the Nth carrier signal may be signals that have been processed such as contention, sampling, and demodulation in a receiver (not shown). The first carrier frequency error detector 110 to the Nth carrier frequency error detector 1N0 have the same configuration.

The first path frequency error detector 111 to the Mth path frequency error detector 11M provided in the first carrier frequency error detector 110 respectively input the first carrier receiving signal, and thus the time of the received signal for each path. Detecting the rate of change of the phase with respect to the output path, and outputs the frequency error for each path of the corresponding first carrier received signal. That is, the first path frequency error detector 111 outputs the first path frequency error, and likewise, the second path frequency error detectors 112 to Mth path frequency error detectors 11M are respectively the second path frequency error to the first path frequency error detector. Outputs the M path frequency error. On the other hand, the first frequency error LOCK determiner 121 to the M-th frequency error LOCK determiner 12M, respectively, and determines whether or not above the set level by checking the strength of the received signal for each path. In addition, the first frequency error lock determiner 121 to the M th frequency error lock determiner 12M respectively transmit a corresponding control signal to the first tri-state gate 131 (Tri-state gate) to the M th tri-state gate ( Output to a control input terminal of 13M) to control the output of the path-specific frequency errors of the first carrier receiving signal. However, at this time, the first frequency error lock determiner 121 to the Mth frequency error lock determiner 12M may be selectively controlled by the control unit (not shown) of the receiving end. The control signals output to the (Tri-State Gate) to the M-th tri-state gate 13M may be output to control the output of the path-specific frequency errors of the first carrier reception signal.

The frequency error combiner 140 combines path-specific frequency errors of the first carrier receiving signal output from each of the first path frequency error detectors 111 to Mth path frequency error detectors 11M, thereby providing a first carrier frequency error. Outputs Meanwhile, the control signals output from the first frequency error lock discriminator 121 to the Mth frequency error lock determiner 12M are output to the input terminal of the OR gate 120. The OR gate 120 outputs a signal having a corresponding level to the control input terminal of the tristate gate 141 according to the input control signals. As a result, when any one of the first path signal to the Mth path signal of the first carrier receiving signal is greater than a predetermined level, the frequency error combiner 140 causes the tristate gate 141 to be controlled by the control signal output from the OR gate. And outputs the combined first carrier frequency error through the output terminal.

The carrier frequency error combiner 150 inputs the first carrier frequency error. In addition, the carrier frequency error combiner 150 inputs the second carrier frequency error to the Nth carrier frequency error output from the second carrier frequency error detector 210 to the Nth carrier frequency error detector N10, respectively. The carrier frequency error combiner 150 combines the first carrier frequency error to the Nth carrier frequency error to output a multicarrier frequency error.

The multicarrier frequency error is converted into a voltage control signal by a digital / analog converter (not shown) provided at the receiving end, and then output to a reference clock generator (not shown) provided at the receiving end. As a result, the reference clock generator outputs a frequency control signal to a plurality of phase control loops for stepping down each carrier reception signal, thereby correcting a frequency error for each carrier frequency signal.

As described above, the multicarrier frequency error combiner according to an embodiment of the present invention combines the carrier frequency error of the first carrier signal to the Nth carrier received signal and outputs the multicarrier frequency error to the reference clock generator. Accordingly, it can be seen that the reference clock generator outputs a frequency control signal to a plurality of phase control loops for stepping down each carrier received signal, thereby correcting a frequency error with respect to the multicarrier received signal.

As described above, the present invention is advantageous in that the frequency error of the multicarrier received signal can be corrected by combining the frequency error for each carrier.

Claims (4)

An apparatus for combining carrier-specific frequency errors of multicarrier received signals in a wireless communication system, A plurality of path frequency error detectors for detecting path-by-path frequency errors of the corresponding received carrier signals; A plurality of frequency error discriminators for controlling output of the frequency error for each path of the plurality of path frequency error detectors by determining whether the path-specific strength of the corresponding carrier received signal is greater than a set level; A frequency error combiner for combining the frequency error for each path output from the plurality of path frequency error detectors, and outputting a carrier frequency error of the corresponding carrier reception signal combined for each path if any of the path-specific intensities of the received signals is greater than a set level. A frequency error detector of the carrier received signal, Frequency error detectors having the same configuration as the frequency error detector and outputting carrier frequency errors of corresponding carrier reception signals, respectively; And a carrier frequency error combiner for outputting a multicarrier frequency error by combining carrier frequency errors output from the frequency error detectors, respectively. The method of claim 1, wherein the carrier received signal, Apparatus characterized in that the signal processing, such as aggregation, sampling and demodulation at the receiving end of the wireless communication system. The method of claim 1, wherein the path frequency error detector, And detecting a frequency error of each path by detecting a change in phase with respect to a time of the received signal of each path. The method of claim 1, wherein the path-specific frequency error output control of the plurality of path frequency error detectors of the plurality of frequency error discriminators includes: And the device is also subjected to selective control of the control unit of the receiving end.