KR100700103B1 - Method for compensating Received Signal Strength Indicator error of multi-Frequency Assignment receiver - Google Patents

Abstract

A method for compensating an RSSI(Received Signal Strength Indicator) error of a multi-frequency assignment receiver is provided to improve RSSI measurement accuracy using software algorithm without additional cost, by calculating an RSSI error due to nonlinear characteristics of each RF signal and then compensating the RSSI error. In a multi FA(Frequency Assignment) receiver for calculating RSSI(Received Signal Strength Indicator) by an automatic power amplitude control value, a judgment step judges whether the compensation of an RSSI error of one FA signal is requested by considering relative amplitude and position in the band of one FA signal for error compensation and other FA signals(S103). A compensation value calculation step calculates an intermodulation component included in the FA signal by using a nonlinear characteristics table on the basis of the amplitude and the position in the band of other FA signals except the one FA signal(S104). An error compensation step compensates the error by applying the calculated compensation value to RSSI of the one FA signal(S105).

Description

Method for compensating Received Signal Strength Indicator error of multi-Frequency Assignment receiver}

1 is a flowchart illustrating a RSSI error compensation method of a multi-FA receiver according to an embodiment of the present invention.

2 is a block diagram showing some components of a conventional 4FA receiver.

3 is a diagram illustrating a form of an input signal capable of generating an error according to a conventional RSSI measurement method.

Explanation of symbols on the main parts of the drawings

10: RF signal processor 20: ADC

30: digital signal processing unit 310 ~ 340: ALC

312 to 342: RSSI register 40: control unit

The present invention relates to a method for compensating a received signal strength indicator (RSSI) error of a multiple frequency (Frequency Assignment) receiver. In particular, another FA signal having a relatively large power level as an input of an antenna is within the same radio frequency (RF) band. The present invention relates to a RSSI error compensation method of a multi-FA receiver suitable for compensating a measurement error of RSSI by receiving at the same time according to a nonlinear RF signal processing characteristic and improving its accuracy.

In general, a signal is finally emitted through an antenna in a wireless mobile communication system. An RF transceiver is located at the end of a system to perform this role.

These RF transmitters and receivers can be largely classified into receivers and transmitters. The receivers receive Rx (Receiver) RF parts and ADCs that properly amplify RF input signals within a dynamic range (DR) range without distortion and apply them to an analog to digital converter (ADC). The digitally converted signal can be divided into an Rx BB portion processed in a base band (BB).

In addition, the transmitter can be divided into a Tx (Transmitter) BB portion and a Tx RF portion that amplifies the DAC output signal without distortion and outputs the desired RF signal size.

In order to perform such a role, the receiver is provided with an Automatic Level Control (ALC) circuit, and the transmitter is provided with an Automatic Gain Control (AGC) circuit.

Many functions of the transceiver are now digitally processed at baseband by digital technology, and in particular, the automatic power size control function of the receiver is also performed digitally.

In addition, the automatic power gain control of the transmitter employs a method of measuring RF power detector and BB power detector values using a micro process and compensating for the error.

On the other hand, the base station receiver must measure the power magnitude of the received RF signal input from the antenna within a margin of error for a specific purpose. In the current W-CDMA mobile communication system, the receiver processes 4FA signals in one RF path, and separates and processes each FA in the BB.

Here, the method of accurately measuring the magnitude of the RF signal input from the antenna is to perform a measurement by placing a separate physical RSSI measurement dedicated path after a low noise amplifier (LNA), but this method is expensive. In general, as shown in FIG. 2, a method of calculating RSSI values for FAs is applied by referring to gain control values of ALCs for each FA in the Rx BB part.

2 is a block diagram showing a part of a conventional 4FA receiver.

As shown in FIG. 2, the RSSI structure for measuring the power size of each FA input RF signal using the ALC function in the receiver amplifies and filters the RF signal, and performs a downlink frequency conversion function. 10, an ADC 20 for converting an analog signal into a digital signal, a digital signal processor 30 for performing channel filtering and ALC functions by separating signals for each FA, and a controller 40 for controlling each device. It is composed of

Here, it is assumed that the RSSI structure of FIG. 2 processes 4FA signals as in the case of W-CDMA.

By this configuration, the multi-FA signal is separated and channel-filtered by each FA in the digital signal processor 30 and is always of constant power regardless of the magnitude of the signal input from the antenna through the ALC 310 to 340 for each FA. It is output as a signal.

At this time, the ALC gain control value used in the ALCs 310 to 340 for each FA depends on the size of the RF input signal, and the controller 40 controls the gain control value, that is, the RSSI registers 312 to 342 for each FA. The power magnitude of the RF signal input from the antenna can be calculated through.

Here, the control unit 40 calculates the RSSI accurately by storing a table of the power magnitude and the ALC gain control value of the RF input signal in advance and referring to the table.

However, the conventional RSSI measurement method has a problem in that RSSI measurement error occurs due to nonlinear RF signal processing when receiving a relatively large power signal.

3 is a diagram illustrating a form of an input signal capable of generating an error according to a conventional RSSI measuring method.

As shown in FIG. 3, when FA signals 1FA, 3FA, and 4FA having a large power level are received in the same RF band, a 2FA signal having a relatively small size due to the nonlinear characteristic of the RF signal processor 10 of FIG. 1. Since an intermodulation component IM is generated in the band and the corresponding signal is distorted, the magnitude of the RF signal corresponding to the original 2FA signal cannot be accurately measured, thereby degrading RSSI measurement accuracy.

The present invention has been proposed to solve the above problems, and in the method of calculating RSSI using an automatic power magnitude control value, nonlinear RF signal processing upon receiving a FA signal having a relatively large power magnitude in the same RF band. An object of the present invention is to provide an RSSI error compensating method of a multi-FA receiver capable of compensating a measurement error of RSSI.

In order to achieve the above object, the present invention provides a relative magnitude and in-band of one FA signal and another FA signal to compensate for errors in a multiple FA receiver for calculating RSSI by an automatic power size control value. A determination step of determining whether RSSI error compensation of the one FA signal is necessary in consideration of a position; A compensation value calculation step of calculating an intermodulation component included in the one FA signal using a non-linear characteristic table stored in advance on the basis of magnitudes and in-band position information of other FA signals except for the one FA signal; And an error compensating step of compensating for the error by applying the calculated compensation value to the RSSI of the one FA signal.

The present invention includes a selection step of selecting an FA signal to be compensated for errors; The FA may further include a calculation step of calculating the RSSI by using the automatic power size control value for each FA.

Preferably, the calculating of the compensation value may be such that the nonlinear characteristic table represents a characteristic by nonlinear RF signal processing of each FA signal.

Preferably, the error compensation may be performed by subtracting the calculated compensation value from the RSSI of the one FA signal.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a RSSI error compensation method of a multi-FA receiver according to an embodiment of the present invention.

RSSI error compensation method of a multi-FA receiver according to an embodiment of the present invention, as shown in Figure 1, the selection step of selecting the FA signal to compensate for the error (S101), and the ALC gain control value for each FA A calculation step (S102) of calculating the RSSI using the error compensation step (S103 to S105) of calculating and compensating for the RSSI error due to the nonlinear characteristic of each RF signal according to the relative magnitude and in-band position between the multiple FA signals. It consists of.

The error compensating step may include determining whether RSSI error compensation of one FA signal is necessary in consideration of the relative magnitude and in-band position of one FA signal and other FA signals to compensate for the error ( S103) and a compensation value calculation for calculating an intermodulation component IM included in one FA signal using a non-linear characteristic table stored in advance based on magnitudes and in-band position information of other FA signals except one FA signal. Step S104, and the compensation step (S105) for applying the calculated compensation value to the RSSI of one FA signal to compensate for the error.

The RSSI error compensation method of the multiple FA receiver according to the embodiment of the present invention configured as described above will be described in more detail with reference to FIGS. 1 to 3.

First, in step S101, when the FA signal to be compensated for is selected, the RSSI error compensation method of the multi-FA receiver is started.

Here, the selected FA signal is, for example, one FA signal arbitrarily selected from among 4FA signals, such as W-CDMA. In order to calculate the RSSI for the entire 4FA signal, steps S102 to S105 as described below are repeated four times. Repeat it.

In step S102, RSSI is calculated for each FA by using an ALC gain control value.

That is, in order to accurately calculate the RSSI of the corresponding FA signal, the RSSI of not only the FA signal but also other FA signals are simultaneously calculated.

Here, the RSSI calculation for the FA signal is performed by the controller 40 using the gain control values of the ALCs 310 to 340 and reading the values stored in the RSSI registers 312 to 342. do.

In step S103, it is determined whether RSSI compensation of the selected corresponding FA signal is necessary.

More specifically, the controller 40 determines whether RSSI error compensation of the FA signal is necessary in consideration of the relative magnitude and in-band position of the FA signal selected to compensate for the error and other FA signals.

For example, as shown in FIG. 3, since an intermodulation component (IM) may be generated in a 2FA signal by a relatively large power 1FA signal, 3FA signal, and 4FA signal, an FA signal other than the corresponding FA signal may be generated. It is determined whether the RSSI error compensation is considered in consideration of the power size and the in-band position of the.

As a result of the determination in step S103, if it is determined that RSSI compensation of the selected FA signal is necessary, that is, if the power size of the selected FA signal is relatively smaller than that of other FA signals, the process proceeds to step S104. The control unit 40 calculates the intermodulation component IM included in the FA signal by using the non-linear characteristic table stored in advance based on the size and in-band position information of other FA signals except the selected FA signal.

Here, the nonlinear characteristic table referred to by the control unit 40 represents the characteristics of the non-linear RF signal processing of each FA signal. In order to accurately calculate the RSSI of the FA signal, the power according to the non-linear characteristics of the RF signal processing unit 10 is calculated. The table of sizes must be stored in advance.

On the other hand, since the RSSI is calculated by the gain control values of the ALCs 310 to 340, when the power magnitude of any one of the FA signals is relatively small, the signal is not generated due to its nonlinear characteristics when the RF signal processing unit 10 processes it. It is distorted and thus acts as an error of RSSI.

For example, when the 2FA signal of FIG. 2 is selected, since the power sizes of the 1FA signal, the 3FA signal, and the 4FA signal are relatively larger than the power sizes of the 2FA signal, the 2FA signal may be applied to the 2FA signal by the nonlinear characteristic of the RF signal processing unit 10. An intermodulation component IM can be generated.

Since the intermodulation component IM corresponds to the RSSI measurement error of 2FA, the controller 40 calculates the intermodulation component IM included in the 2FA signal by using a prestored nonlinear characteristic table.

As a result of the determination in step S103, when it is determined that RSSI compensation of the selected FA signal is not necessary, that is, when the power magnitude of the selected FA signal is not relatively small compared to the power magnitude of other FA signals, the FA signal is determined. It is determined that the RSSI has been accurately measured, and the process proceeds to step S105 without performing error compensation thereto.

In step S105, the calculated compensation value is applied to the RSSI of the corresponding FA signal to compensate for the error.

Here, the calculated compensation value corresponds to the intermodulation component IM, and means an error value of the RSSI. The controller 40 subtracts the compensation value calculated as described above from the RSSI of the corresponding FA signal, The RSSI of the FA signal can be calculated accurately.

For example, if the 2FA signal of Fig. 2 is selected for its correction, the control unit 40 subtracts the intermodulation component IM calculated with reference to the nonlinear characteristic table from the RSSI currently calculated as in step S104.

Steps S101 to S105 are performed on one FA signal among multiple FA signals, and thus, the RSSI of each FA signal can be accurately calculated by repeatedly performing all FA signals.

In this manner, the RSSI error compensation method of the multi-FA receiver according to the embodiment of the present invention is terminated.

As described above, the RSSI error compensation method of the multi-FA receiver according to the present invention calculates and compensates for the RSSI error due to the non-linear characteristics of each RF signal according to the relative magnitude of the multi-FA signal and the in-band position, thereby providing RF input. In order to accurately measure the power magnitude of the signal, it is possible to improve RSSI measurement accuracy by using a software algorithm without installing an additional device in the existing receiver structure, that is, no additional cost.

In addition, the present invention calculates the intermodulation component included in the FA signal by using a non-linear characteristic table stored in advance, so that the measurement error of the RSSI by nonlinear RF signal processing upon receiving a FA signal having a relatively large power level in the same RF band. There is an effect to compensate.

Claims (4)

In a multiple frequency (Frequency Assignment) receiver that calculates a Received Signal Strength Indicator (RSSI) based on an automatic power magnitude control value, A determination step of determining whether RSSI error compensation of the one FA signal is necessary in consideration of the relative magnitude and in-band position of one FA signal and another FA signal to be compensated for; Calculating an intermodulation component included in the FA signal by using a non-linear characteristic table stored in advance on the basis of magnitudes and in-band position information of other FA signals except for the FA signal; ; And applying the calculated compensation value to the RSSI of the one FA signal to compensate for the error. The method of claim 1, Selecting an FA signal to compensate for the error; RSSI error compensation method of the multi-FA receiver, characterized in that further comprising the step of calculating the RSSI by using the automatic power size control value for each FA. The method of claim 1, Computing the compensation value RSSS error compensation method of the multi-FA receiver, characterized in that the non-linear characteristic table represents the characteristic by the non-linear RF signal processing of each FA signal. The method of claim 1, The error compensating step, the RSSI error compensation method of the multi-FA receiver, characterized in that by subtracting the calculated compensation value from the RSSI of the one FA signal.

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