KR101237605B1 - Apparatus and method for controlling of gain in a mobile terminal - Google Patents

Abstract

The present invention relates to an apparatus and method for controlling gain in a mobile communication terminal, and more particularly, to an apparatus and method for controlling gain of a received signal in a mobile communication terminal.

An apparatus for controlling a gain of a received signal in a mobile terminal according to the present invention may determine a signal strength by accumulating a difference between the strength of a received signal and a reference intensity for a predetermined time, and determine a gain mode according to the determined signal strength. A gain calculator for determining a buffer, a buffer controller for calculating amplification values according to the linear characteristics of the amplifying elements, and outputting the amplification values to the respective buffers, and amplifying values according to the calculated linear characteristics according to the determined gain mode. A multiplexer for outputting a compensation value of the determined signal strength, an accelerometer for outputting a compensated signal strength by performing an amplification operation on the determined signal strength and the compensation value, and controlling gains according to nonlinear characteristics of the amplifying elements. Information for storing the signal strength and outputting a gain signal from the compensated signal strength Contains a table.

Signal strength, RSSI, receiver, gain control, analog and analog device

Description

Gain control device and method in mobile communication terminal {APPARATUS AND METHOD FOR CONTROLLING OF GAIN IN A MOBILE TERMINAL}

1 is a functional block diagram illustrating control of gain by receiving a radio signal in a mobile terminal;

2 is a functional block diagram for gain control of a received signal provided in a general mobile terminal;

3 is an internal block diagram of a gain control unit included in a mobile terminal according to an embodiment of the present invention;

4 is a diagram illustrating a configuration of a signal strength table 310 according to the present invention;

5 is a characteristic graph of an analog element for explaining the non-linear characteristics of the analog element.

The present invention relates to an apparatus and method for controlling gain in a mobile communication terminal, and more particularly, to an apparatus and method for controlling gain of a received signal in a mobile communication terminal.

In general, a mobile communication system is a device that secures mobility in a terminal so that a user can perform communication without restriction of location and distance. As such, the mobile communication system communicates with the terminal using a radio signal in order to secure mobility in the terminal. Since a mobile communication terminal uses a radio signal, the signal must be amplified in order to maintain the reception signal level according to the distance from the base station or the channel condition with the base station. As such, the gain of the received signal received from the base station should be adjusted to a different level depending on the level of the received signal. Therefore, the mobile terminal operates with various gain modes. Next, a process for controlling gain in the mobile terminal will be described with reference to FIG. 1.

1 is a functional block diagram illustrating the control of a gain by receiving a radio signal in a mobile terminal.

First, the received signal is received through the antenna ANT. The received signal is input to the wireless receiver 110 through a duplexer 101 for distinguishing a path between the transmitted signal and the received signal. The wireless receiver 110 is a device for converting the received radio signal by band-down conversion into a baseband signal. The wireless receiver 110 includes a low noise amplifier, a mixer for band down conversion, and an amplifier such as an OP-AMP for amplifying a signal level. In addition, the mixer may be composed of one or more mixers according to the band down conversion method. Accordingly, the wireless receiver 110 not only converts a received signal into a baseband signal but also amplifies the signal using the low noise amplifier, the mixer, and another amplifier. The amplified baseband signal is input to the modem 140 and the gain control unit 120.

The modem 140 demodulates, decodes, and outputs the received baseband signal, and encodes, modulates, and outputs a signal for transmission. The encoded and modulated baseband signal is input to the wireless transmitter 130. The wireless transmitter 130 receives the gain control signal from the gain control unit 120 to control the wireless amplification degree of the elements, and converts the signal into a wireless signal to provide the duplexer 101. Then, the duplexer 101 separates the transmitted signal from the received signal and transmits the transmitted signal to the base station through the antenna ANT.

The gain controller 120 determines the level of the received signal using the strength of the signal received from the wireless receiver 110, and determines the gain mode accordingly. The gains of the devices included in the wireless receiver 110 are determined according to the gain mode determined as described above, and the transmission power and the gain of the wireless transmitter 130 are determined. Then, a configuration for controlling the gain by receiving the signal from the wireless receiver 110 will be described in more detail with reference to FIG. 2.

2 is a functional block diagram for gain control of a received signal included in a general mobile terminal.

The signal output from the wireless unit 110 is input to an analog-to-digital converter (ADC) 121. The analog-to-digital converter 121 converts the received analog signal into a digital signal and outputs it to the gain calculator 122. The gain calculator 122 then checks the level of the received signal, calculates a difference from the reference intensity, and accumulates it for a predetermined time to determine the signal strength RSSI. In addition, the gain calculator 122 calculates a gain mode according to the signal strength. The gain mode calculated as described above is input to the control signal of the multiplexer 124, and the strength of the received signal is input to each signal strength table provided in the memory unit 123. The signal strength table stores a gain value according to a linear section and a non-linear section according to the gain mode of each device. First, the signal strength table will be described.

First, gain control devices, such as low-noise amplifiers, mixers, and OP-AMPs, have linear amplification in certain areas, but nonlinear in other areas. Therefore, there is a problem that it is difficult to express the gain elements in the first-order equation because there is a linear section and a non-linear section. Therefore, since the amplification according to the gain mode must be performed to meet the nonlinear characteristics as described above, in the RSSI table, a value for adjusting the gain of each device is stored in each gain mode according to the received signal strength. This is because the nonlinear characteristics of the devices have their own characteristics. Therefore, the number of each received signal table is determined according to the number of gain modes. As such, a manufacturing company that commercializes a product in order to determine gain values of the devices according to the received signal strength configures the gain control with the minimum power when controlling the gain values of the devices.

As described above, the signal output from each table is input to the multiplexer 124, and the multiplexer 124 outputs a gain control signal according to a corresponding gain mode. The gain control signal output as described above is converted into an analog signal through a digital analog converter (DAC) 125 and then input to analog elements for controlling each gain of the wireless receiver 110 to control gain.

In the gain control unit 120 configured as described above, a plurality of tables must be provided according to each gain mode. This is because there is a linear and nonlinear characteristic of each device in the corresponding gain mode. Therefore, there is a problem that requires a lot of memory when configuring the control unit 120. This in turn acts as a factor in raising the unit price of the product.

Accordingly, an object of the present invention is to provide an apparatus and method for easily configuring a configuration for gain control of an analog device in a mobile terminal.

Another object of the present invention is to provide an apparatus and method for controlling gain inexpensive in a mobile terminal.

Another object of the present invention is to provide an apparatus and method for using less memory when configuring an apparatus for gain control in a mobile terminal.

An apparatus for controlling a gain of a received signal in a mobile terminal according to the present invention may determine a signal strength by accumulating a difference between the strength of a received signal and a reference intensity for a predetermined time, and determine a gain mode according to the determined signal strength. A gain calculator for determining a buffer, a buffer controller for calculating amplification values according to the linear characteristics of the amplifying elements, and outputting the amplification values to the respective buffers, and amplifying values according to the calculated linear characteristics according to the determined gain mode. A multiplexer for outputting a compensation value of the determined signal strength, an accelerometer for outputting a compensated signal strength by performing an amplification operation on the determined signal strength and the compensation value, and controlling gains according to nonlinear characteristics of the amplifying elements. Information for storing the signal strength and outputting a gain signal from the compensated signal strength Contains a table.

In addition, the gain control method in the mobile terminal according to the present invention, a step of determining the signal strength by accumulating the difference between the strength of the received signal and the reference intensity for a predetermined time, and determining the gain mode according to the determined signal strength, and amplification Calculating amplification values according to the linear characteristics of the devices and outputting them to the respective buffers, and outputting the amplification values according to the calculated linear characteristics as compensation values of the determined signal strength according to the determined gain mode. And a process of outputting a compensated signal strength by performing an addition / decrement operation on the determined signal strength and the compensation value, and a signal strength table storing information for controlling gain according to nonlinear characteristics of the amplifying elements. And outputting a gain signal from the compensated signal strength.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when 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. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to a user's or operator's intention or custom. Therefore, the definition should be based on the contents throughout this specification.

In the present invention described below, the configuration according to the present invention, the operation according to the present invention and the verification and effects thereof will be described in order.

<Configuration according to the present invention>

3 is an internal block diagram of a gain control unit included in a mobile terminal according to an exemplary embodiment of the present invention. Hereinafter, an internal configuration and operation of the gain control unit according to the present invention will be described in detail with reference to FIG. 3.

First, since the analog-to-digital converter 121 and the digital-to-analog converter 125 have the same configuration as described in the related art and perform the same operation, a detailed description thereof will be omitted.

The digital signal received from the analog to digital converter 121 is input to the gain calculator 301. The gain calculator 310 checks the level of the received signal to calculate a difference from the reference intensity, and accumulates it for a predetermined time to determine the signal strength RSSI. In addition, the gain calculator 310 calculates a gain mode according to the signal strength. The gain mode calculated as described above is input to the control signal of the multiplexer 302, and the strength of the received signal is input to the modulator 303.

Meanwhile, the buffer controller 331 according to the present invention inputs a linear gain mode value to each of the buffers 321, 322, and 323 of the buffer 320. Each of the buffers 321, 322, and 323 may be configured as a queue for storing a gain control value. Each signal output from the buffer 320 is input to the multiplexer 302. The multiplexer 302 then outputs a specific signal based on the input signal under the control of the gain calculator 301.

The signal output as described above is input to the retarder 303 to correct the received signal level. The signal whose level of the received signal is corrected is input to the signal strength table 310. In the present invention, only one signal strength table 310 is configured. This is used to compensate for other nonlinear characteristics to control the gain value of the device for each gain mode. When the gain signal is determined in the signal strength table 310, the gain signal is output through the digital-to-analog converter 125.

<Operation and Verification thereof According to the Present Invention>

As described above, the operation according to the configuration of the gain control unit according to the present invention will be described.

The gain control unit of the mobile terminal according to the present invention assumes that there are N gain modes. In this case, it is assumed that gain mode 1 is a mode with the smallest gain and gain mode N is a mode with the largest gain. In addition, the signal strength (RSSI) table according to the present invention is composed of L fields. This will be described with reference to FIG. 4.

4 is a diagram illustrating the configuration of the signal strength table 310 according to the present invention.

The signal strength table according to the present invention is composed of a total of L rows from the 0 th row to the L-1 th row. In addition, the gain of each row has the largest gain in the 0th row and the smallest gain in the L-1th row. In other words, the smaller the row number, the higher the gain, and the larger the row number, the lower the gain. Therefore, the received signal strength (RSSI) value has the smallest value in row 0 and has the largest value in row L-1. In addition, as shown in FIG. 4, the gain values included in each row are composed of M bits.

In this case, let the maximum input signal strength be Imax and the minimum input signal strength be Imin. And any gain mode is called n. Assume that the strength compensation value of the received signal in any gain mode n is Cn, and the received signal strength (RSSI) at this time is Xn. Gain mode n is then valid for In-min and In-max. However, N> 0, L> 0, M> 0, I unit is dBm.

Next, a general operation will be described under the above assumption.

First, the gain calculator 301 calculates the RSSI (Xn) by accumulating a difference value between the intensity of the input signal and the reference intensity for a predetermined period. The gain calculator 301 determines the gain mode n based on the calculated Xn. When the gain mode is determined in this way, the RSSI compensation value Cn corresponding to the determined gain mode is added to Xn. The gain of the analog device value calculated as described above, that is, the analog device gain value corresponding to Xn + Cn is obtained as follows.

(1) The i-th RSSI table value is called RSSI {i}.

(2) If RSSI {i}> RSSI {i + 1}, then Xn + Cn> [Xn + Cn].

At this time, if Xn + Cn-[Xn + Cn] is 0, RSSI {[Xn + Cn]}. The operation "[x]" here means a maximum integer not exceeding x. Xn + Cn-[Xn + Cn] is 0 means that the value of Xn + Cn is an integer value. However, if Xn + Cn-[Xn + Cn] is not 0, the calculation is performed in the form of Equation 1 below.

RSSI {[Xn + Cn]} + (RSSI {[Xn + Cn]}-RSSI {[Xn + Cn] + 1}) * (Xn + Cn-[Xn + Cn]) * L / 2 ^ M

Equation 1 describes a process performed to find a specific signal in the signal strength table 310. That is, the value of RSSI {[Xn + Cn]} means that the actual received signal level is larger than when selecting a value of a specific row, but it is necessary to select a lower value. And the meaning of (RSSI {[Xn + Cn]}-RSSI {[Xn + Cn] + 1}) thus selects the value of the next row, and the first term of the values to be subsequently multiplied is It is an expression that calculates how much. Also, the second term multiplied by the value of the next row is a calculated value for normalizing the values of the overall gain modes to the value of M bits. In this way, the normalization process makes it possible to detect an appropriate gain value between a row that a particular received signal level should select and a gain value larger than that row.

Next, the operation when the RSSI compensation value Cn changes from 0 to a non-zero value will be described. At this time, it is assumed that the strength of the input signal does not change.

If Cn is initially zero, both RSSI and compensated RSSI are Xn. If Cn is changed to a non-zero value, the compensated RSSI is Xn + Cn. If Cn is a positive value, the compensated RSSI becomes large, and the analog device gain is reduced by Cn. Therefore, after looping, RSSI becomes Xn-Cn, and the compensated RSSI becomes Xn. The analog device gain converges to the same value as when Cn is zero by the loop. By this principle, if Cn is not 0, the effect of subtracting RSSI value by Cn without affecting the operation of the automatic gain control loop (AGC loop).

<The method of configuring RSSI compensation value and RSSI table for each gain mode according to the present invention>

5 is a characteristic graph of an analog device for explaining the nonlinear characteristics of the analog device.

As shown in FIG. 5, the analog device has a nonlinear characteristic. However, the graph of reference numeral 501 shows the amplification of the low noise amplifier, the graph of reference numeral 502 shows the amplification of the mixer, and the reference numeral 503 shows the amplification of the OP-AMP. In each graph, the low noise amplifier ranges from -16dBm to -70dBm, the mixer ranges from -28dBm to -82dBm, and the OP-AMP ranges from -40dBm to -88dBm. . This is because devices like LNA and Mixer can behave as linear devices in certain areas. However, the nonlinear nature of the OP-Amp device is inevitable in the graph at 503, which is the gain mode for the smallest input. Therefore, no matter how many steps, only the characteristics of the mode with the largest gain are stored in the signal strength (RSSI) table 310, and in the mode with less gain, the analog device is operated only in the linear section. 310 may be shared. The procedure for finding the RSSI compensation value in each gain mode is as follows.

Initially, the RSSI compensation value is set to zero. In the signal strength (RSSI) table, a linearly converted value of RSSI is input according to the number of bits of an analog device gain value. Then set the gain mode to n. Record the analog device gain at In-min. Then set the maximum gain mode to N. Adjust the external input strength so that the analog device gain is the value found in the analog device gain at In-min. At this time, the external input strength is referred to as I _Nn .

Then, when the gain mode is n, the RSSI compensation value Cn is determined as shown in Equation 2 below.

(I _Nn -In-min) * 2 ^ M / (Imax-Imin)

In the above assumption, the RSSI compensation value CN of the largest gain mode is zero.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, by reducing the memory capacity of the signal strength table used for the appropriate gain mode of the analog device to the external strength in the receiver of the mobile communication system, power consumption, hardware cost reduction, and correction of the received analog device can be achieved. There is an advantage to this.

Claims (4)

An apparatus for controlling the gain of a received signal in a mobile terminal, A gain calculator configured to determine a signal strength by accumulating a difference between the strength of the received signal and a reference strength for a predetermined time, and determine a gain mode according to the determined signal strength; A buffer controller for calculating amplification degree values according to linear characteristics of the amplifying elements and outputting the amplification values to the respective buffers; A multiplexer for outputting amplification values according to the calculated linear characteristics as a compensation value of the determined signal strength according to the determined gain mode; An accelerator for outputting a compensated signal strength by performing an acceleration / decrease operation on the determined signal strength and the compensation value; And a signal strength table that stores information for controlling gain according to nonlinear characteristics of the amplifying elements, and outputs a gain signal from the compensated signal strength. The method of claim 1, wherein the signal strength table, A gain control device comprising a plurality of rows according to a plurality of signal strengths, each row comprising a gain signal of an amplifying element having a non-linear characteristic among the amplifying elements. In the gain control method in a mobile terminal, Determining a signal strength by accumulating the difference between the strength of the received signal and the reference strength for a predetermined time, and determining a gain mode according to the determined signal strength; Calculating amplification values according to the linear characteristics of the amplifying elements and outputting them to the respective buffers; Outputting amplification values according to the calculated linear characteristics as a compensation value of the determined signal strength according to the determined gain mode; Outputting a compensated signal strength by performing an addition or decrement operation on the determined signal strength and the compensation value; And outputting a gain signal from the compensated signal strength by referring to a signal strength table in which information for controlling gain according to nonlinear characteristics of the amplifying elements is stored. The method of claim 3, wherein the signal strength table, A gain control method comprising a plurality of rows according to a plurality of signal strengths, each row comprising a gain signal of an amplifying element having a non-linear characteristic among the amplifying elements.

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