KR20030037469A - Method and Apparatus for Measurement of SIR(Signal to Interference Ratio) using Partitioned Despreading of Pilot Symbol in CDMA System - Google Patents

Abstract

PURPOSE: A device for measuring a signal to interference ratio using a division-despread pilot symbol in a CDMA system and a method thereof are provided to variably control a section of despreading a pilot symbol received from a terminal, and to division-despread the section, thereby increasing samples of measurable pilot symbols and exactly calculating a signal to interference ratio. CONSTITUTION: A pilot symbol despreader(101) receives a pilot symbol, and performs a division-despreading process by variably controlling a despreading section to be smaller than a spread coefficient, then increases samples of measurable pilot symbols. A coherent demodulator(102) coherent-demodulates a despread pilot symbol inputted from the pilot symbol despreader(101). A signal to interference ratio measurer(103) inputs the coherent-demodulated pilot symbol from the coherent demodulator(102), and measures a signal to interference ratio.

Description

Apparatus and method for measuring signal-to-interference ratio using split despread pilot symbols in code division multiple access system {Method and Apparatus for Measurement of Signal to Interference Ratio (SIR) using Partitioned Despreading of Pilot Symbol in CDMA System}

The present invention relates to an apparatus for measuring signal-to-interference ratio using split despread pilot symbols in a code division multiple access system, and a method thereof and a computer-readable recording medium recording a program for realizing the method. In more detail, the base station variably adjusts the interval for despreading the pilot symbols received from the terminal to split despread, thereby increasing the number of samples of the measurable pilot symbols, and calculating the signal-to-interference ratio with improved accuracy. Ultimately, the power control performance is improved.

In the related art, a method using an unassigned orthogonal code among orthogonal codes for securing orthogonality between channels or a filtering method has been proposed in order to measure the signal-to-interference ratio.

However, in the method of allocating orthogonal codes for interference power measurement using the conventionally proposed method, there is a possibility that the capacity of the system is reduced by the number of orthogonal codes allocated thereto. Due to the limitation in that the filter coefficients cannot be variably applied, the interference power measurement is inaccurate, and the complexity of the receiver is inevitably increased to overcome this problem.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and an apparatus and method for measuring a signal-to-interference ratio for measuring a signal-to-noise ratio using a pilot despread pilot symbol in a code division multiple access system And a computer readable recording medium having recorded thereon a program for realizing the above method.

That is, the present invention despreads a control channel to which a fixed spreading factor is applied, not by an orthogonal code assignment or an inaccurate filtering technique that causes a capacity reduction of a system to a channel where a base station is currently establishing a call for reverse power control. In this case, the number of samples of the pilot symbols that can be measured is increased by variably adjusting the despreading interval by adjusting the despreading interval smaller than the fixed spreading coefficient and ultimately calculating the signal-to-interference ratio with improved accuracy using only the received pilot symbol power. Improve power control performance In addition, through this method, the number of pilot symbols in the measurement interval for measuring the signal-to-interference ratio is variable, so that it is possible to measure the signal-to-interference ratio more accurately in the measurement interval in which there are not enough pilot symbols to measure the signal power. Do.

1 is an overall configuration diagram of an apparatus for measuring a signal-to-interference ratio using a coherent demodulated pilot symbol according to the present invention.

2 is a detailed block diagram of a pilot symbol despreading unit having a variable despreading section in a signal-to-interference ratio measuring apparatus using coherent demodulated pilot symbols according to the present invention;

3 is a detailed block diagram of a signal-to-interference ratio measuring unit of a signal-to-interference ratio measuring apparatus using a coherent demodulated pilot symbol according to the present invention;

Figure 4 is an overall configuration diagram of an apparatus for measuring a signal-to-interference ratio using a non-coherent demodulated pilot symbol according to the present invention.

5 is a detailed block diagram of a pilot symbol despreading unit having a variable despreading interval in a signal-to-interference ratio measuring apparatus using non-coherent demodulated pilot symbols according to the present invention.

6 is a detailed configuration diagram of an embodiment of a signal-to-interference ratio measuring unit of a signal-to-interference ratio measuring apparatus using a non-coherent demodulated pilot symbol according to the present invention.

7 is a flowchart illustrating a method for measuring a signal-to-interference ratio using a coherent demodulated pilot symbol according to the present invention.

8 is a flowchart illustrating a method for measuring a signal-to-interference ratio using non-coherent demodulated pilot symbols according to the present invention.

* Explanation of symbols for the main parts of the drawings

100, 200: signal-to-interference ratio measuring device 101, 201: pilot symbol despreader

102: coherent demodulation unit 103, 203: signal to interference ratio measurement unit

202: I-coherent demodulator

According to an aspect of the present invention, there is provided a signal-to-interference ratio measuring apparatus using a pilot symbol that is coherent demodulated and divided and despread in a code division multiple access system. Pilot symbol despreading means for increasing the number of samples of pilot symbols that can be received by performing a variable despreading by variably adjusting the despreading interval to be smaller than a spreading coefficient which is fixed and operated; Coherent demodulation means for coherent demodulating the despread pilot symbols received from the pilot symbol despreading means; And signal-to-interference ratio measuring means for receiving a coherent demodulated pilot symbol from the coherent demodulation means and measuring the signal-to-interference ratio.

The present invention also provides a signal-to-interference ratio measurement apparatus using a non-coherent demodulated, despread-spread pilot symbol in a code division multiple access system, wherein the pilot symbols are received and operated in a fixed manner. Pilot symbol despreading means for increasing the number of samples of the pilot symbols that can be measured by performing a variable despreading by variably adjusting a despreading interval smaller than a spreading factor; Non-coherent demodulation means for non-coherent demodulation of the despread pilot symbols received from the pilot symbol despreading means; And signal-to-interference ratio measuring means for measuring the signal-to-interference ratio by receiving the non-coherent demodulated pilot symbols from the non-coherent demodulation means.

Meanwhile, the present invention provides a signal-to-interference ratio measurement method using pilot symbols coherent demodulated and divided despread in a code division multiple access system, comprising: a first step of dividing and despreading a pilot symbol by adjusting a despreading period; Combining the pilot symbols of the split despread multipath; A third step of calculating an average signal power using the combined pilot symbol; A fourth step of calculating an average interference power by using the average signal power and the received power in divided despread symbol units; And a fifth step of determining a signal-to-interference ratio by dividing the average signal power by the average interference power.

The present invention also provides a signal-to-interference ratio measurement method using a non-coherent demodulated and split despread pilot symbol in a code division multiple access system, the first step of splitting and despreading a pilot symbol by adjusting a despreading interval. ; A second step of measuring a received power using the split despread pilot symbol; A third step of calculating an average signal power by dividing the received power by the number of symbols during a unit interval; A fourth step of measuring received power in symbol units by squared pilot symbols divided and despread in the first step; A fifth step of calculating an average interference power using the average signal power and the received power in symbol units; And determining a signal-to-interference ratio by dividing the average signal power by the average interference power.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall configuration diagram of an apparatus for measuring signal-to-interference ratio using coherent demodulated pilot symbols according to the present invention, in which "100" is a signal-to-interference ratio measuring apparatus and "101" is a pilot symbol despreading "102" denotes a coherent demodulator and "103" denotes a signal-to-interference ratio measurement unit, respectively.

Here, the coherent demodulated pilot symbol means a pilot symbol that is coherently demodulated for each multipath by estimating and compensating information on a phase change amount due to fading of a radio channel in a channel estimator. do.

As shown in FIG. 1, the coherent demodulated signal-to-interference ratio measuring apparatus 100 according to the present invention receives a pilot symbol and variably adjusts the despreading interval to be smaller than the spreading factor operated while being fixed. Coherent demodulation of despread pilot symbols received from pilot symbol despreader 101 and pilot symbol despreader 101 to increase the number of samples of measurable pilot symbols by performing spreading And a coherent demodulator 102 and a coherent demodulated pilot symbol from the coherent demodulator 102, and a signal-to-interference ratio measurement unit 103 for measuring the signal-to-interference ratio.

FIG. 2 is a detailed block diagram of a pilot symbol despreading unit having a variable despreading interval in a signal-to-interference ratio measuring apparatus using a coherent demodulated pilot symbol according to the present invention. "105" denotes an orthogonal code generator, "106" denotes a despread interval controller, and "107" denotes an integration and a dumper, respectively.

As shown in FIG. 2, the pilot symbol despreader 101 includes a despreader 104, an orthogonal code generator 105, a despread section adjuster 106, and an integration and dumper 107. do.

Although not shown in FIG. 2, the despreader 104 includes a channel estimator for estimating and compensating for information on a phase change amount due to fading of a wireless channel in the channel estimator.

On the other hand, the despreading section adjusting unit 106 despreads the section spreading the pilot symbol in the despreader 104 smaller than the spreading factor is operated fixed for the reverse control channel in the code division multiple access system It performs a function of increasing the number of samples of pilot symbols by performing variable despreading by variably adjusting and has an important feature in the present invention.

On the other hand, in a spread spectrum communication system, a spreading factor spreads at a transmitting end and despreads at a receiving end, and a minimum unit is a chip after spreading and despreading, and spreads before spreading and after spreading. The symbol consisting of chips as many as the coefficient is the minimum unit. Therefore, after passing through the despreader 104, a module for accumulating the despread chip by the spreading factor by the symbol unit is required. The integration and dumper 107 is responsible for such a function. That is, the integration and dumper 107 is responsible for accumulating the despread chip information by a spreading factor and forming one symbol.

3 is a detailed block diagram of a signal-to-interference ratio measuring unit in a signal-to-interference ratio measuring apparatus using a coherent demodulated pilot symbol according to the present invention, in which "108" is a combiner and "109" is a pilot. The symbol accumulator, "110" represents a signal power calculator, "111" represents an interference power meter, "112" represents an interference power meter, and "113" represents a signal to interference ratio calculator.

As shown in FIG. 3, the signal-to-interference ratio measuring unit 103 includes one or more pilot symbols received per unit section for power control and a combiner 108 for performing a maximum ratio combination of signals. The signal power calculator 110 for extracting the signal power per unit section from the pilot symbol accumulator 109 and the pilot symbol accumulator 109 for accumulating the signals, and the remainder obtained by subtracting each pilot symbol power from the signal power per unit interval. And the interference power calculator 112 for calculating the interference power per unit section by using the sum of the outputs of the interference power meter 111 and the output of the interference power meter 111 to measure the interference power, and the signal power per unit section. And a signal-to-interference ratio calculator 113 for calculating the signal-to-interference ratio using the interference power.

In the combiner 108, a maximum ratio combine of signals is performed. In this case, the maximum ratio combining is performed so that the coherent demodulator 102 receives the channel with the smallest amount of phase change for each multipath and has the minimum gain for the channel with the large amount of phase change. This means that the demodulated outputs are demodulated to have the maximum gain in the order of the smallest amount of phase change experienced by each of the multipaths.

Meanwhile, in order to estimate the signal power, N pilot symbols received per unit section for power control are accumulated in the pilot symbol accumulator 109 to extract the signal power per unit chip in the signal power calculator 110. Using the remaining power obtained by subtracting the calculated signal power from each pilot symbol power received during the measurement period, the interference power is extracted from the interference power meter 111, and using the sum per unit chip of the output of the interference power meter 111, The interference power calculator 112 calculates the interference power per unit chip. The signal-to-interference ratio is calculated by the signal-to-interference ratio calculator 113 by using the signal power and the interference power per unit chip calculated above.

4 is an overall configuration diagram of an apparatus for measuring a signal-to-interference ratio using a non-coherent demodulated pilot symbol according to the present invention, in which "200" is a signal-to-interference ratio measuring apparatus and "201" is a pilot symbol. The despreading section, "202" represents a non-coherent demodulation section, and "203" represents a signal-to-interference ratio measuring section, respectively.

If it is difficult to coherently demodulate the pilot symbol by using channel estimation information on the current communication channel in order to meet the delay limit of the power control limited in the CDMA system, the despreader 201 The received M multipath pilot symbols are directly input to the signal-to-interference ratio measurement unit 203 through the non-coherent demodulator 202.

Here, the non-coherent demodulation means a method of demodulating only the output of the despreader without correcting the amount of phase change by the channel estimator, unlike coherent demodulation.

As shown in FIG. 4, the non-coherent demodulated signal-to-interference ratio measuring apparatus 200 according to the present invention receives a pilot symbol and variably adjusts the despreading interval to be smaller than a spreading coefficient that is operated fixed. Non-coherent (Non) the despread pilot symbols received from the pilot symbol despreader 201 and the pilot symbol despreader 201 to increase the number of samples of the pilot symbols measurable by performing the partial despreading. Signal-to-interference ratio for inputting non-coherent demodulated pilot symbols from non-coherent demodulator 202 and non-coherent demodulator 202 for coherent demodulation The measuring unit 203 is included.

FIG. 5 is a detailed block diagram of a pilot symbol despreading unit having a variable despreading interval in a signal-to-interference ratio measurement apparatus using non-coherent demodulated pilot symbols according to the present invention. A spreader, "205" denotes an orthogonal code generator, "206" denotes a despreading interval adjuster, and "207" denotes an integration and a dumper, respectively.

As shown in FIG. 5, the pilot symbol despreader 201 includes a despreader 204, an orthogonal code generator 205, a despread segment adjuster 206, and an integration and dumper 207. do.

Here, the function of each module is similar to that of FIG. 2 except that the despreader 204 does not include a channel estimator unlike the case of a coherent demodulated pilot symbol.

FIG. 6 is a detailed configuration diagram of a signal-to-interference ratio measuring unit of a signal-to-interference ratio measuring apparatus using non-coherent demodulated pilot symbols according to the present invention. A signal power calculator, "210" represents an interference power meter, "211" represents an interference power calculator, and "212" represents a signal to interference ratio calculator, respectively.

As shown in FIG. 6, the signal-to-interference ratio measuring unit 203 accumulates the energy of the pilot symbol divided and despread for each multipath for a unit period, and then takes a square to measure a power of a received signal. 208 and a signal power calculator 209 for extracting signal power per unit section from the multiplier 208 and an interference power meter for measuring interference power by using the remainder of the pilot symbol power subtracted from the signal power ( Calculating the signal-to-interference ratio using the interference power calculator 211 for calculating the interference power per unit section using the sum of the output of the interference power measuring unit 210 and the output of the interference power measuring unit 210 and the signal power and interference power per unit section. And a signal to interference ratio calculator 212.

Non-coherent demodulation, unlike coherent demodulation, is a method of demodulating only the output of the despreader 201 without correcting a phase change amount by a channel estimator. The signal power received through the square 208 that squares the despread information and the channel estimation information by multiplying the despread information by the complex operation instead of the multiplication by the complex operation is obtained.

Here, the functions of the modules of FIG. 3 are similar to those of the module 208.

7 is a flowchart illustrating a method for measuring a signal-to-interference ratio using a coherent demodulated pilot symbol according to the present invention.

First, the pilot symbol is divided and despreaded by adjusting the despreading interval (300). That is, the number of samples of pilot symbols for signal power measurement is increased by dividing and despreading by adjusting the despreading interval to be smaller than the fixed despreading coefficient.

Thereafter, the divided despread pilot symbols coming through the multipath are combined (301).

Subsequently, the signal power is measured by accumulating the divided despread sub symbol power in symbol units (S302).

The average signal power is then calculated (303). That is, the average signal power is calculated by dividing the accumulated unit signal power in symbol units by the number of symbols during the unit interval.

Meanwhile, the reception power is buffered in units of the sub-spread subsymbols (304).

Next, the average interference power is calculated (305). That is, the average interference power is calculated by subtracting the received power of the sub despreaded subsymbol unit from the average signal power and dividing by the number of sub despread subsymbols during the unit interval.

Finally, the signal to interference ratio is determined (306). That is, the signal-to-interference ratio is determined by dividing the average signal power by the average interference power.

8 is a flowchart illustrating a method for measuring a signal-to-interference ratio using non-coherent demodulated pilot symbols according to the present invention.

First, the despreading period is adjusted to divide and despread in sub-symbol units (400).

Subsequently, the received power is measured by accumulating subsymbol energy divided and spread for each multipath for a unit interval and taking a square of the received power (401).

The average signal power is then calculated (402). That is, the average signal power is calculated by dividing the received power during the accumulated unit interval by the number of symbols during the unit interval.

On the other hand, the power of the subsymbol unit of the divided despread unit is squared to receive power of the subsymbol unit (403).

Subsequently, the received power in subsymbols is added to the multipath and then buffered (404).

The average interference power is then calculated (405). That is, the average interference power is calculated by subtracting the received power of the divided despread unit from the average signal power and dividing the resultant result by the number of divided despread subsymbols during the unit interval.

Finally, the signal-to-interference ratio is determined by dividing the average signal power by the average interference power (406).

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

As described above, the present invention provides a measurement for signal-to-interference ratio measurement by variably adjusting the despreading section to a section smaller than the fixed spreading factor applied by the transmitter during the despreading of the spreading channel for the fixed control channel. The number of pilot symbols received is increased for the measurement interval in which the number of pilot symbols during the interval is not enough to measure the signal power, and the signal-to-interference ratio is measured using only the received pilot symbol power. By improving the accuracy of the signal-to-interference ratio measurement and ultimately improving the power control performance, the system capacity can be increased.

Claims (12)

In the signal-to-interference ratio measuring apparatus using a pilot symbol, Pilot symbol despreading means for increasing the number of samples of pilot symbols that can be measured by receiving the pilot symbols and variably adjusting the despreading intervals to be smaller than the spreading coefficients operated in a fixed manner; Coherent demodulation means for coherent demodulating the despread pilot symbols received from the pilot symbol despreading means; And Signal-to-interference ratio measuring means for measuring a signal-to-interference ratio by receiving a coherent demodulated pilot symbol from the coherent demodulation means Signal-to-interference ratio measuring apparatus using a coherent demodulated and split despread pilot symbols in a code division multiple access system comprising a. The method of claim 1, The pilot symbol despreading means, Signal spreader measurement apparatus using a coherent demodulated split-spread pilot symbol in a code division multiple access system, characterized in that it comprises a despreading interval adjusting means for adjusting the width of the despreading interval for the pilot symbol . The method of claim 1, The signal-to-interference ratio measuring means, Combining means for performing a maximum ratio combine of the signals; Pilot symbol accumulating means for accumulating one or more received pilot symbols per unit section for power control; Signal power calculating means for extracting signal power per unit section from the pilot symbol accumulating means; Interference power measuring means for measuring interference power by using the remainder of each pilot symbol power subtracted from the signal power per unit section; Interference power calculating means for calculating interference power per unit section using a sum per unit section of the output of the interference power measuring means; And Signal-to-interference ratio calculating means for calculating the signal-to-interference ratio using the signal power and the interference power per unit section Signal-to-interference ratio measurement apparatus using a coherent demodulated and split despread pilot symbols in a code division multiple access system comprising a. In the signal-to-interference ratio measuring apparatus using a pilot symbol, Pilot symbol despreading means for increasing the number of samples of pilot symbols that can be measured by receiving the pilot symbols and variably adjusting the despreading intervals to be smaller than the spreading coefficients operated in a fixed manner; Non-coherent demodulation means for non-coherent demodulation of the despread pilot symbols received from the pilot symbol despreading means; And Signal-to-interference ratio measuring means for measuring signal-to-interference ratio by receiving non-coherent demodulated pilot symbols from the non-coherent demodulation means Signal-to-interference ratio measurement apparatus using a non-coherent demodulated and split despread pilot symbols in a code division multiple access system comprising a. The method of claim 4, wherein The pilot symbol despreading means, Signal spreader ratio using a non-coherent demodulated split despread pilot symbol in a code division multiple access system, characterized in that it comprises a despreading interval adjusting means for adjusting the width of the despreading interval for the pilot symbol Measuring device. The method of claim 4, wherein The signal-to-interference ratio measuring means, Pilot symbol measuring means for accumulating the energy of the pilot symbol divided and despread for each multipath for a unit period, and then taking a square to measure received power; Signal power calculating means for extracting signal power per unit section from the pilot symbol measuring means; Interference power measuring means for measuring interference power using the remainder obtained by subtracting each pilot symbol power from the signal power; Interference power calculating means for calculating interference power per unit section using a sum per unit section of the output of the interference power measuring means; And Signal-to-interference ratio calculating means for calculating the signal-to-interference ratio using the signal power and the interference power per unit section Signal-to-interference ratio measurement apparatus using a non-coherent demodulated and split despread pilot symbols in a code division multiple access system comprising a. In the signal-to-interference ratio measurement method using a pilot symbol, A first step of dividing and despreading a pilot symbol by adjusting a despreading interval; Combining the pilot symbols of the split despread multipath; A third step of calculating an average signal power using the combined pilot symbol; A fourth step of calculating an average interference power by using the average signal power and the received power in divided despread symbol units; And A fifth step of determining a signal-to-interference ratio by dividing the average signal power by the average interference power Signal-to-interference ratio measurement method using a coherent demodulated split despread pilot symbol in a code division multiple access system comprising a. The method of claim 7, wherein The third step, In the code division multiple access system, the average signal power is calculated by accumulating the power of the combined pilot symbol in symbol units and dividing the accumulated unit signal power in symbol units by the number of symbols during the unit interval. A method of measuring signal-to-interference ratio using demodulated and despread pilot symbols. The method of claim 7, wherein The fourth step, In the code division multiple access system, the average power is calculated by subtracting the received power of the divided despread symbol unit from the average signal power, and dividing the sum of the subtracted values by the number of divided despread symbols during the unit interval. A method of measuring signal-to-interference ratio using coherent demodulated and split despread pilot symbols. In the signal-to-interference ratio measurement method using a pilot symbol, A first step of dividing and despreading a pilot symbol by adjusting a despreading interval; A second step of measuring a received power using the split despread pilot symbol; A third step of calculating an average signal power by dividing the received power by the number of symbols during a unit interval; A fourth step of measuring received power in symbol units by squared pilot symbols divided and despread in the first step; A fifth step of calculating an average interference power using the average signal power and the received power in symbol units; And A sixth step of determining a signal-to-interference ratio by dividing the average signal power by the average interference power Signal-to-interference ratio measurement method using a non-coherent demodulated split despread pilot symbol in a code division multiple access system comprising a. The method of claim 10, The second step, In the code division multiple access system, a pilot symbol energy, which is divided by multipaths, is accumulated for a unit interval, and the power is measured by taking a square, using non-coherent demodulated pilot symbols that are non-coherent demodulated. Signal to interference ratio measurement method. The method of claim 10, The fifth step, In the code division multiple access system, the average power is calculated by subtracting the received power of each symbol unit from the average signal power and dividing the sum of the subtracted values by the number of divided despread symbols during a unit interval. A method of measuring signal-to-interference ratio using coherent demodulated and split despread pilot symbols.