KR20020078372A - Apparatus for forward polarization diversity in a IMT-2000 system - Google Patents

Abstract

PURPOSE: A forward polarization diversity apparatus for an IMT-2000(International Mobile Telecommunication) system is provided to decrease fading influence by composing two reception dedicated chip antennas in an IMT-2000 terminal and embodying the polarization diversity. CONSTITUTION: The second and third multipliers(102,103) multiply an output signal of the first multiplier(101) by baseband I and Q signals, respectively. The fourth and fifth multipliers(107,108) multiply a signal outputted from a QPSK(Quadrature Phase Shift Keying) modulating unit(106) by a certain white noise, respectively. The sixth and seventh multipliers(109,110) multiply the signals outputted from the fourth and fifth multipliers(107,108) by the baseband I and Q signals, respectively. The first adder(111) adds a pilot signal outputted from the second multiplier(102) and a transmission signal outputted from the sixth multiplier(109). The second adder(112) adds a pilot signal outputted from the third multiplier(103) and a transmission signal outputted from the seventh multiplier(110). The first and second FIR(Finite Impulse Response) filters(113,114) filter the signals outputted from the first and second adders(111,112). The eighth multiplier(115) multiplies the baseband I signal outputted from the first FIR filter(113) by a certain frequency and polarizes the multiplied signal. The ninth multiplier(116) multiplies the baseband Q signal outputted from the second FIR filter(114) by a certain frequency and polarizes the multiplied signal. The third adder(117) adds the baseband I signal outputted from the eighth multiplier(115) and the baseband Q signal outputted from the ninth multiplier(116). An antenna(118) transmits the output signal of the third adder(117) to a mobile station.

Description

Apparatus for forward polarization diversity in a IMT-2000 system

The present invention relates to a device for forward polarization diversity in a mobile communication system (particularly, a CDMA type IMT-2000 system). In particular, an IMT-2000 terminal includes two reception-only chip antennas and uses polarization using the same. The present invention relates to a forward polarization diversity apparatus in an IMT-2000 system that reduces fading effects by implementing diversity.

In the next generation mobile communication system (IMT-2000 system) for CDMA, which is currently being developed, research is being conducted to improve reception performance using two antennas in the forward link like the reverse link of IS-95. One of the main goals of the IMT-2000 system, which is expected to begin service in the early 2000s, is to provide improved performance over current cellular or personal mobile communication systems (PCS). One such effort is to improve performance by combining at the receiver side signals that are distributed over multiple paths using path diversity.

In particular, in a wireless channel environment that suffers from fading, such as mobile communication, the power of a received signal changes rapidly over time. Therefore, the diversity gain obtained by reducing the effects of fading using a diversity technique is known to be quite large.

In IS-95, a standard adopted by cellular systems and PCS, the diversity effect is obtained by using two receiving antennas at the base station in the reverse link connected from the terminal station to the base station.

That is, in the conventional forward transmission diversity method, a mobile station (terminal) compares two signals transmitted from two antennas of a base station, and selects and demodulates a signal having a larger reception power.

However, the conventional forward diversity method has a disadvantage in that the cost and installation cost of the system are considerably high because two RF parts and two antennas of the transmitter are installed in the base station.

In addition, a method for distinguishing a transmission antenna of a base station has also emerged as a very difficult problem.

Accordingly, the present invention has been proposed to solve various problems occurring in the conventional forward diversity implementation as described above.

An object of the present invention is to provide a forward polarization diversity apparatus in an IMT-2000 system in which an IMT-2000 terminal has two reception-only chip antennas and implements polarization diversity using the same. There is.

In order to achieve the above object, the present invention separates transmission and reception paths by using two reception-only chip antennas and a transmission-only helical antenna in a mobile station. In addition, each receive-only chip antenna receives signals having different polarizations when receiving signals from the base station, and then compares the two signals to select a large signal, thereby improving fading characteristics.

In addition, the separation of the transmitting and receiving end can reduce the loss of the signal due to the use of the duplexer, and also to solve the mechanical problems of the terminal due to the increase of the antenna by using the chip antenna.

The forward diversity apparatus in the IMT-2000 system according to the present invention for achieving the above object,

In the forward diversity apparatus of a mobile communication system comprising a base station and a mobile station,

The transmitting end of the base station,

Second and third multipliers that multiply baseband I and Q signals by an output signal of a first multiplier that multiplies a transmission pilot signal by a white noise;

Fourth and fifth multipliers for multiplying predetermined white noise by a signal output from a QPSK modulator for modulating a transmission signal passing through an interleaver for interleaving an output signal of an encoder encoding transmission data in a QPSK scheme;

A sixth and seventh multiplier which multiplies baseband I and Q signals by signals output from the fourth and fifth multipliers, respectively;

A first adder for adding a pilot signal output from the second multiplier and a transmission signal output from the sixth multiplier;

A second adder for adding a pilot signal output from the third multiplier and a transmission signal output from the seventh multiplier;

First and second finite impulse response (FIR) filters respectively filtering signals output from the first and second adders;

An eighth multiplier configured to multiply and polarize the baseband I signal output from the first FIR filter by a predetermined frequency;

A ninth multiplier for multiplying a baseband Q signal output from the second FIR filter by a predetermined frequency to polarize the signal;

A third adder for adding the polarized baseband I signal output from the eighth multiplier and the polarized baseband Q signal output from the ninth multiplier;

And an antenna for transmitting the output signal of the third adder to the mobile station.

The forward diversity apparatus in the IMT-2000 system according to the present invention for achieving the above object,

In the forward diversity apparatus of a mobile communication system comprising a base station and a mobile station,

The receiving end of the mobile station,

A first chip antenna for receiving a signal transmitted from the base station;

First and second multipliers for multiplying the signals received from the first chip antenna by frequencies having different phases, respectively;

First and second finite impulse response (FIR) filters for filtering output signals of the first and second multipliers, respectively;

A first summer for summing output signals of the first and second FIR filters for a predetermined period;

A second chip antenna for receiving a signal transmitted from the base station having a predetermined polarization with the first chip antenna;

Third and fourth multipliers for multiplying the signals received at the second chip antenna by frequencies having different phases, respectively;

Third and fourth finite impulse response (FIR) filters for filtering output signals of the third and fourth multipliers, respectively;

A second adder for summing output signals of the third and fourth FIR filters for a predetermined period;

A combiner for comparing the output signals of the first and second summers to select and output a received signal having a large signal;

A deinterleaver for deinterleaving the output signal of the combiner;

And a decoder that demodulates the output signal of the deinterleaver into an original signal and outputs the received signal as a received signal.

FIG. 1 is a diagram illustrating a configuration of a transmitting end of a base station in a forward polarization diversity apparatus in an IMT-2000 system according to the present invention.

2 is a diagram illustrating a configuration of a receiving end of a mobile station in a forward polarization diversity apparatus in an IMT-2000 system according to the present invention.

<Explanation of symbols for the main parts of the drawings>

115, 116 ..... 8th and 9th multipliers

117 ..... 3rd adder

201, 207 ..... First and second chip antennas

206, 212 ..... first and second summer

213 ..... Combiner

Hereinafter, a preferred embodiment of the forward polarization diversity apparatus in the IMT-2000 system according to the present invention according to the technical spirit as described above is as follows.

The present invention is intended to improve fading characteristics by employing two receive-only chip antennas having different polarizations in a terminal.

That is, the base station installs only one transmitting antenna, and the terminal implements polarization diversity using two reception-only chip antennas having different polarizations.

Here, polarization diversity uses two signals having independent fading characteristics. The difference from the spatial diversity is that the polarizations of two antennas are different from each other, not spaced apart from two reception antennas. The polarization of the signal transmitted from the transmitter is reflected or diffracted by an obstacle such as a building, and its polarization characteristics change, and each of the multipath signals has different polarization.

In this case, if two antennas having different polarizations are installed at the receiving end, two signals having independent fading characteristics are obtained.

The receive-only chip antenna applied to the present invention uses an antenna having a polarization characteristic of 45 ° to the left and right from the vertical direction, which means that when a vertical polarization signal is transmitted, the polarization signal tilted 45 ° to the left and right from the vertical direction is most likely. This is because they are large and have the least correlation with each other.

In addition, since the mobile station (terminal) of the present invention separates the antennas of the transmitter and the receiver, the duplexer is unnecessary, and the loss of the signal by the duplexer can be prevented, thereby improving the sensitivity of the receiver and increasing the power efficiency of the transmitter.

Hereinafter, preferred embodiments will be described with reference to the concept of the present invention as described above.

1 is a diagram illustrating a configuration of a transmitting end of a base station of a forward polarization diversity apparatus in an IMT-2000 system according to the present invention.

Here, reference numeral 101 denotes a first multiplier that multiplies the transmission pilot signal by white noise (W ₀ ), and reference numerals 102 and 103 denote baseband I and Q signals (P), respectively, on the output signal of the first multiplier 101. _I ) denotes second and third multipliers multiplying (P _Q ), reference numeral 104 denotes an encoder for encoding transmission data, reference numeral 105 denotes an interleaver for interleaving an output signal of the encoder 104, Reference numeral 106 denotes a QPSK modulator for modulating a transmission signal output from the interleaver 105 in a QPSK scheme.

Further, reference numerals 107 and 108 denote fourth and fifth multipliers that multiply predetermined white noise W _N by the signal output from the QPSK modulator 106, and reference numerals 109 and 110 denote the above-mentioned. The sixth and seventh multipliers for multiplying the baseband I and Q signals P _I (P _Q ) by the signals output from the fourth and fifth multipliers 107 and 108, respectively, and reference numeral 111 denotes the first and second multipliers. The first adder adds the pilot signal output from the multiplier 102 and the transmission signal output from the sixth multiplier 109, and reference numeral 112 denotes a pilot signal output from the third multiplier 103. And a second adder for adding the transmission signal output from the seventh multiplier 110.

Reference numerals 113 and 114 denote first and second finite impulse response (FIR) filters for filtering signals output from the first and second adders 111 and 112, respectively. The baseband I signal output from the first FIR filter 113 has a predetermined frequency ( ) And an eighth multiplier for polarization by multiplying the reference signal. And a ninth multiplier to polarize by multiplying N), and reference numeral 117 denotes a polarized baseband I signal output from the eighth multiplier 115 and a polarized baseband Q signal output from the ninth multiplier 116. A third adder to be added is shown, and reference numeral 118 denotes an antenna for transmitting the output signal of the third adder 117 to the mobile station.

In the IMT-2000 system according to the present invention configured as described above, the base station transmitter of the forward polarization diversity apparatus first multiplies the white noise (W ₀ ) by the pilot signal (Pilot) to be transmitted by the first multiplier (101), The second multiplier 102 multiplies the baseband I signal P _{I by} the output signal of the first multiplier 101, and outputs the third multiplier 103 to the output signal of the first multiplier 101. The baseband Q signal P _Q is multiplied and output.

Next, the encoder 104 encodes the data to be transmitted, the interleaver 105 performs interleaving for error correction of the encoded data, and the QPSK modulator 106 modulates the interleaved transmission data by QPSK modulation. Do

Then, the fourth and fifth multipliers 107 and 108 mix white noise W _N with the signal modulated by the QPSK modulator 106, respectively, and the sixth multiplier 109 uses the fourth multiplier ( The baseband I signal P _I is mixed with the output signal of 107 and output, and the seventh multiplier 110 outputs the baseband Q signal P _{Q with} the output signal of the fifth multiplier 108. do.

Next, the first adder 111 adds the pilot signal for the baseband I signal output from the second multiplier 102 and the transmission data for the baseband I signal output from the sixth multiplier 109. The second adder 112 adds the pilot signal for the baseband Q signal output from the third multiplier 103 and the transmission data for the baseband Q signal output from the seventh multiplier 110. do.

In addition, the first FIR filter 113 filters the signal output from the first adder 111, and the second FIR filter 114 filters the signal output from the second adder 112.

Next, the eighth multiplier 115 may apply a predetermined frequency to the baseband I signal output from the first FIR filter 113. ), And the ninth multiplier 116 multiplies the baseband Q signal output from the second FIR filter 114 by a predetermined frequency. ), I.e. the predetermined frequency ( ) And polarized wave by mixing a frequency 180 degrees out of phase.

The signals polarized in this manner are added by the third adder 117 and then transmitted to the mobile station through one transmission antenna 118.

2 is a diagram showing the configuration of a mobile station receiver in a forward polarization diversity apparatus in an IMT-2000 system according to the present invention.

Here, reference numeral 201 denotes a first chip antenna for receiving a signal transmitted from the base station, and reference numerals 202 and 203 denote frequencies of a predetermined different phase to the signal received from the first chip antenna 201, respectively. First and second multipliers, and reference numerals 204 and 205 denote first and second finite impulse response (FIR) filters for filtering output signals of the first and second multipliers 202 and 203, respectively. Reference numeral 206 denotes a first summer for summing output signals of the first and second FIR filters 204 and 205 for a predetermined period.

Further, reference numeral 207 denotes a second chip antenna for receiving a signal transmitted from the base station with a predetermined polarization with the first chip antenna 201, and reference numerals 208 and 209 denote the second chip antenna 207. Denotes third and fourth multipliers that multiply frequencies of different phases by the received signals, respectively, and reference numerals 210 and 211 denote output signals of the third and fourth multipliers 208 and 209, respectively. A third and fourth finite impulse response (FIR) filters are shown, and reference numeral 212 denotes a second summer that adds up the output signals of the third and fourth FIR filters 210 and 211 for a predetermined period.

Reference numeral 213 denotes a combiner for comparing the output signals of the first and second summers 206 and 212 to select a signal having a large signal strength as a received signal, and reference numeral 214 denotes a combiner 213 of the combiner 213. A deinterleaver for deinterleaving the output signal is shown. Reference numeral 215 denotes a decoder for demodulating the output signal of the deinterleaver 214 into an original signal and outputting it as a received signal.

The mobile station receiving end according to the present invention configured as described above receives a signal transmitted from the base station from the first chip antenna 201, and the first and second multipliers 202 and 203 receive the first chip antenna 201. Each received signal at) has a different phase frequency ( ).

Next, the first and second FIR filters 204 and 205 filter the signals output from the first and second multipliers 202 and 203, respectively, and the first summer 206 is the first filter. The output signals of the first and second FIR filters 204 and 205 are summed for a predetermined period and output to the combiner 213.

In addition, the second chip antenna 207 receives a signal transmitted from the base station with a predetermined polarization with respect to the first chip antenna 201, and the third and fourth multipliers 208 and 209 receive the first chip. The signals received from the two-chip antenna 207 have frequencies of different phases, respectively. Multiply by.

Next, the third and fourth FIR filters 210 and 211 filter the output signals of the third and fourth multipliers 208 and 209, respectively, and the second summer 212 filters the third and fourth filters. The output signals of the fourth FIR filters 210 and 211 are added to the combiner 213 for a predetermined period.

The combiner 213 compares the output signals of the first and second summers 206 and 212 and selects and outputs a signal having a large signal strength as a received signal. That is, a signal with less fading influence is output. In addition, the deinterleaver 214 deinterleaves the output signal of the combiner 213, and the decoder 215 demodulates the output signal of the deinterleaver 214 into an original signal and outputs the received signal.

That is, the mobile station receives signals having different polarizations by using two reception-only chip antennas, and compares the two signals to select a signal having a large signal strength, thereby improving fading characteristics.

According to the above-described "forward polarization diversity apparatus in IMT-2000 system", the mobile station includes two antennas having different polarizations, and acquires two signals having independent fading characteristics and thus has a large signal strength. By selecting the signal as the received signal, there is an advantage that a signal with less fading influence can be obtained.

In addition, the receiving end of the mobile station can remove the duplexer by separating the receiving antenna and the transmitting antenna separately, the signal loss can be prevented by the removal of the duplexer and the sensitivity of the receiving end can be improved, which is the power efficiency of the base station transmitting end There is also an advantage that can be increased.

In addition, since the mobile station implements polarization diversity by itself, the transmit end of the base station can perform forward diversity using only one transmit antenna, thereby reducing the installation cost of the base station.

Claims (3)

In the forward diversity apparatus of a mobile communication system comprising a base station and a mobile station, The transmitting end of the base station, Second and third multipliers that multiply baseband I and Q signals by an output signal of a first multiplier that multiplies a transmission pilot signal by a white noise; Fourth and fifth multipliers for multiplying predetermined white noise by a signal output from a QPSK modulator for modulating a transmission signal passing through an interleaver for interleaving an output signal of an encoder encoding transmission data in a QPSK scheme; A sixth and seventh multiplier which multiplies baseband I and Q signals by signals output from the fourth and fifth multipliers, respectively; A first adder for adding a pilot signal output from the second multiplier and a transmission signal output from the sixth multiplier; A second adder for adding a pilot signal output from the third multiplier and a transmission signal output from the seventh multiplier; First and second finite impulse response (FIR) filters respectively filtering signals output from the first and second adders; An eighth multiplier configured to multiply and polarize the baseband I signal output from the first FIR filter by a predetermined frequency; A ninth multiplier for multiplying a baseband Q signal output from the second FIR filter by a predetermined frequency to polarize the signal; A third adder for adding the polarized baseband I signal output from the eighth multiplier and the polarized baseband Q signal output from the ninth multiplier; And an antenna for transmitting the output signal of the third adder to the mobile station. A forward diversity apparatus of a mobile communication system including a base station transmitter and a mobile station receiver, The receiving end of the mobile station, A first chip antenna for receiving a signal transmitted from the base station; First and second multipliers for multiplying the signals received from the first chip antenna by frequencies having different phases, respectively; First and second finite impulse response (FIR) filters for filtering output signals of the first and second multipliers, respectively; A first summer for summing output signals of the first and second FIR filters for a predetermined period; A second chip antenna for receiving a signal transmitted from the base station having a predetermined polarization with the first chip antenna; Third and fourth multipliers for multiplying the signals received at the second chip antenna by frequencies having different phases, respectively; Third and fourth finite impulse response (FIR) filters for filtering output signals of the third and fourth multipliers, respectively; A second adder for summing output signals of the third and fourth FIR filters for a predetermined period; A combiner for comparing the output signals of the first and second summers to select and output a signal having a large signal strength as a received signal; A deinterleaver for deinterleaving the output signal of the combiner; And a decoder for demodulating the output signal of the deinterleaver to an original signal and outputting the demodulated signal as a received signal. 3. The apparatus of claim 2, wherein the second chip antenna receives a signal having a 45 ° polarization relative to the signal received from the first chip antenna. 4.