WO2008029458A1

WO2008029458A1 - Radio transmitting apparatus, radio receiving apparatus and wireless communication system

Info

Publication number: WO2008029458A1
Application number: PCT/JP2006/317660
Authority: WO
Inventors: Katsuya Oda; Takashi Enoki
Original assignee: Panasonic Corporation
Priority date: 2006-09-06
Filing date: 2006-09-06
Publication date: 2008-03-13

Abstract

A wireless communication system capable of providing both a phase noise canceler function and a MIMO communication function. In this wireless communication system, if there exist a plurality of propagation paths, a radio transmitting apparatus (100) superimposes a pilot signal for phase noise cancellation on only one of the plurality of propagation paths. A radio receiving apparatus (200) extracts and uses the pilot signal for quadrature demodulations of the signals of all of the propagation paths. That is, in the radio receiving apparatus (200), the pilot signal is extracted by a bandpass filter (210), then amplified by an amplifier (211), then distributed into two systems by a second distributor (212) and then used by quadrature demodulation parts (209a,209b) to perform the quadrature demodulations of the signals of all of the propagation paths.

Description

Wireless transmission device, wireless reception device, and wireless communication system

Technical field

The present invention relates to a radio transmission apparatus, radio reception apparatus, and radio communication system having a phase noise cancellation function and a MIMO (Multiple Input Multipie Output: spatial multiplexing) communication function using multiple antennas.

Background art

Conventionally, various measures have been taken in order to provide a wireless communication system with excellent phase noise characteristics, and the technology of this type of wireless communication system is disclosed in Patent Document 1, for example. FIG. 1 is a block diagram showing an example of a wireless receiver in a conventional wireless communication system with improved phase noise characteristics. The radio receiver shown in FIG. 1 has a local “noise” canceller to improve the phase noise characteristics. FIG. 2 is a characteristic diagram showing the frequency characteristics of each component of the local noise canceller in the wireless receiver of FIG. In other words, the symbols in each black circle in FIG. 1 correspond to the characteristic diagrams of the respective symbols in FIG.

Accordingly, the operation of the local “noise” canceller in the radio reception apparatus of FIG. 1 will be described with reference to FIG. As shown in Fig. 2 (A), the input signal (A) input to distributor 1 of the wireless receiver shown in Fig. 1 is the modulated IF signal (BBT-OFDM) and pilot carrier (PILOT). Are multiplexed and the input phase noise (thick diagonal line) is superimposed. Here, the frequency of the no-carrier (PILOT) in the input signal, IF signal (BBT-OFDM), that is, the frequency of the input signal is f, and the input phase noise

PLT sig

Where Θ (t) is the input phase noise Θ (t) superimposed on f and f.

PLT sig PLT and f are respectively expressed by the following equations.

sig

f Ζ Θ (t)

PLT

f Z Θ (t)

sig

[0004] The input signal (A) is distributed by distributor 1, one is output to the pilot branch, and the other is output to the signal branch (modulation signal branch). Distribution in the pilot branch One of the signals distributed by the filter 1 is band-limited by the band-pass filter (BPF) 2 and only the component of the pilot 'carrier (PILOT) is passed through and extracted, and is further limited by the limiter amplifier 3 The At this time, the IF signal component is removed from the frequency characteristics of the output signal (B) output from BPF2 and the output signal (C) output from the limiter amplifier 3 as shown in Fig. 2 (B Therefore, only the pilot 'carrier (PILOT) component and the input phase noise 0 (t) superimposed on it are included.

[0005] At this time, a delay occurs in BPF2, and if this delay time is τ, the input pilot key

BPF1

The carrier frequency f has a delay time τ

Input phase noise delayed by BPF1 0 (t— τ)

Since PLT BPF1 is superimposed !, the incoming canolot carrier frequency f is expressed as follows.

PLT

f Z Θ (t- τ)

PLT BPF1

On the other hand, in the signal branch distributed by distributor 1, local oscillator signal (D) is output from local oscillator 4. Here, the frequency characteristics of the local oscillation signal (D), in which the local oscillator 4 power is also output, are as shown in Fig. 2 (D), and the local oscillation phase (LO) signal superimposed on the local oscillation frequency (LO) signal. Noise. Here, the local oscillation signal frequency in the system is expressed as f

When LO is the local oscillation phase noise in the system and Φ (t), the local oscillation signal frequency f in the system is f

Since the local oscillation phase noise Φ (t) is superimposed on LO, the local oscillation signal frequency f is given by

LO

Shown in

f

LO)

[0007] In the signal branch, the input signal output from the distributor 1 is frequency-converted by the multiplier (mixer) 5 with the local oscillator signal (D) of four local oscillators, and the multiplier 5 Signal (E) is output. Here, the frequency characteristics of the signal (E) output from the multiplier 5 are the sum and difference components of the input signal (A) and the local oscillation signal (D) as shown in Fig. 2 (E). Exists. Therefore, the relationship between each signal component included in the signal) and the superimposed phase noise is as follows.

f -f Ζ Θ (t)-(t)

PLT LO

f f Z Θ (t)-(t)

sig LO

f + f Z Θ (t) + (t)

PLT LO

f + f Z Θ (t) + (t) [0008] Since the frequency-converted signal (E) is band-limited so that only the difference component passes through the band-pass filter (BPF) 6, the signal (F) is output from the BPF 6. In the frequency characteristics of this signal (F), as shown in Fig. 2 (F), the sum component in the signal) is removed and only the difference component exists. At this time, a delay occurs in BPF6.

BPF

Assuming 2, the phase noise superimposed on the extracted difference component has a delay time τ

A delay occurs only for BPF2. At this time, the relationship between each signal component included in the signal (F) and the superimposed phase noise is as follows.

f -f Z Θ (t- τ)-(t- τ)

PLT LO BPF2 BPF2

f -f Ζ θ (t- τ)-(t- τ)

sig LO BPF2 BPF2

[0009] Then, a delay amount is added to the signal) in the delay corrector 7 so as to be equivalent to the delay time in the BPF2 of the pilot branch, and the signal (G) is output from the delay corrector 7. Here, with respect to the delay time τ of the bandpass filter (BPF) 2, the bandpass filter

BPF1

(BPF) 6 delay time is τ and delay corrector 7 delay time is At.

BPF2

τ = τ + At

BPFl BPF2

Thus, the delay compensator 7 adds a delay At to the signal) to equalize the delay time difference from the pilot branch.

[0010] As a result, the frequency characteristic of the signal (G) does not change, and the waveform is as shown in Fig. 2 (G). The relationship between each signal component included in the signal (G) and the superimposed phase noise Is obtained by adding the delay Δt to the phase noise.

f -ί Ζ Θ (t- τ At)-(t- τ-At)

PLT LO BPF2- BPF2

f f Z Θ (t- τ-At)-(t- τ-At)

sig LO BPF2 BPF2

[0011] The signal (G) of the signal branch and the pilot branch signal (C) output from the limiter amplifier 3 are frequency-converted by the frequency change 8, and the signal (H) Is output.

[0012] Here, the frequency characteristic of the signal (H) output from the frequency shift 8 is the sum and difference components of the signal (G) and the signal (C) as shown in Fig. 2 (H). Exists. Therefore, the relationship between each signal component contained in signal (H) and the superimposed phase noise is as follows. f — (f -f) Ζ θ (t-τ)-{0 (t- T -Α) -φ (ί ~ τ -At)}

PLT PLT O BPFl BPF2 BPF2 f — (ff) Z Θ (t-τ)-{0 (t- T -Μ) -φ (ί ~ τ -At)}

PLT sig LO BPF1 BPF2 BPF2

f + (f -f) Z Θ (t-τ) + {0 (t- T -At)-(t- T -At)}

PLT PLT O BPF1 BPF2 BPF2

f + (f f) Z Θ (t-τ) + {0 (t- T -At)-(t- T -At)}

BPF2

[0013] As described above, the delay time of the delay corrector 7 is

τ = τ + At

BPFl BPF2

Thus, the delay Δt is added to equalize the delay time difference between the signal branch and the pilot branch, so the above equation can be rearranged as follows.

f Z (t- τ -At)

LO BPF2

f one (f one f) Z (t- τ -At)

LO sig PLT BPF2

2Xf f Z2X Θ (t- τ)-(t- τ-At)

PLT LO BPFl BPF2

f + (f -f) Z2X Θ (t- τ)-(t- τ At)

PLT sig LO BPFl BPF2

[0014] Here, focusing on the difference component, the frequency of the output signal component is the frequency of the local oscillation signal (f) in the system related to the frequency of the input signal.

LO, that is, constant. In addition, when the pilot 'carrier is focused, the sideband of the signal is inverted at the input and output. Also, the phase noise of the output signal is canceled by the input phase noise Θ (X) and becomes the phase noise φ (X) of the local oscillation signal in the system instead. That is, the phase noise φ of the local oscillation signal in the system

If (X) is sufficiently small, the phase noise of the input signal is sufficiently reduced and output.

[0015] Therefore, the signal (H) frequency-converted by the frequency conversion 8 is band-limited so that only the difference component and only the signal component pass through the band-pass filter (BPF) 9, and the signal is transmitted from the BPF 9. (I) is output. As shown in Fig. 2 (1), the frequency characteristics of this signal (I) are such that only the signal component of the difference component exists by removing the pilot / carrier component in the sum and difference components of signal (H). . At this time, the relationship between the signal component included in the signal (I) and the superimposed phase noise is expressed by the following equation.

f one (f one f) Ζ (t- τ -At)

LO sig PLT BPF2

[0016] Due to the principle of frequency synchronization and noise removal of the local noise canceller, for example, even if there is a frequency deviation in the input signal, high stability is achieved with high frequency accuracy generated by the local oscillator 4. Output signal with frequency according to local oscillation frequency Therefore, the frequency deviation of the input signal can be eliminated. Also, the phase noise of the output signal is canceled by the phase noise Θ (X) superimposed on the input signal, and instead becomes only the phase noise φ (X) of the local oscillation signal in the system. If the phase noise Φ (X) of the local oscillation signal is sufficiently small, the phase noise of the input signal is sufficiently reduced and output.

Patent Document 1: JP 2002-152158 A

Disclosure of the invention

Problems to be solved by the invention

However, in the conventional wireless communication system, no consideration is given to a system to which MIMO technology for performing multi-antenna communication by combining a plurality of antennas is applied. In the conventional wireless communication system, when phase noise is canceled, channel phase information in all paths is canceled out, and it becomes impossible to separate a plurality of data sequences by MIMO matrix calculation.

[0018] Hereinafter, the reason why it becomes impossible to separate a plurality of data sequences by a MIMO matrix operation in a conventional wireless communication system will be described in detail with reference to FIG. FIG. 3 is a block diagram showing a configuration of a radio transmission apparatus and a radio reception apparatus when a phase noise cancellation technique is applied during MIMO communication in a conventional radio communication system. The wireless communication system shown in FIG. 3 includes a wireless transmission device 10 and a wireless reception device 20 that perform MIMO communication.

The baseband signal output from the transmission baseband unit (transmission BB unit) 11 of the wireless transmission device 10 is separated into two systems by the MIMO separation unit 12. One baseband signal is orthogonally modulated by the orthogonal modulation unit 13a, and further input to the transmission RF unit 14a and frequency-converted to an RF signal (radio signal) by the local oscillator 15. The other baseband signal is quadrature modulated by the quadrature modulation unit 13b, further input to the transmission RF unit 14b, and frequency-converted to an RF signal (radio signal) by the local oscillator 15. As a result, a radio signal is transmitted from the transmission antenna 16a of the transmission RF unit 14a via the path 1 and the path 2, and the radio signal is transmitted from the transmission antenna 16b of the transmission RF unit 14b via the path 3 and the path 4. Issue is sent. At this time, the pilot signal for canceling the phase noise is transmitted through all propagation paths. It is superimposed on the line signal.

[0020] The radio signal transmitted from the transmission antenna 16a via the path 1 has propagation path phase information Θ

1 is added, and propagation path phase information Θ 2 is added to the radio signal transmitted from the transmission antenna 16a via the path 2. Further, the propagation path phase information Θ 3 is added to the radio signal transmitted from the transmission antenna 16b via the path 3, and the propagation path phase information Θ 4 is transmitted to the radio signal transmitted from the transmission antenna 16b via the path 4. Is added.

In radio receiving apparatus 20, receiving antenna 21a receives a radio signal to which propagation path phase information θ 1 is added from path 1, and a radio signal to which propagation path phase information Θ 3 is added from path 3. Receive. That is, the receiving antenna 21a receives the radio signals of the route 1 and the route 3 mixed. The receiving antenna 21b receives a radio signal to which the propagation path phase information Θ2 is added from the path 2 and receives a radio signal to which the propagation path phase information Θ4 is added from the path 4. In other words, the receiving antenna 2 lb receives in a state where the wireless signals of the route 2 and the route 4 are mixed.

[0022] A radio signal (including propagation path phase information Θ 1 and Θ 3) received by the receiving antenna 21a is amplified by the amplifier 22a and then mixed with the reference signal of the local oscillator 24 by the multiplier 23a. The frequency is converted into an IF signal, and further input to the distributor 27a via the band pass filter 25a and the variable amplifier 26a. This IF signal is distributed to the modulated signal branch and the pilot branch by the distributor 27a, and is input to the orthogonal demodulator 29a via the delay corrector 28a in the modulated signal branch. In the pilot branch, the pilot signal is extracted by the band pass filter 30a, amplified by the amplifier 31a, and then input to the quadrature demodulator 29a.

The quadrature demodulator 29a cancels the phase noise by subtracting (E−F) the signal (F) that is the pilot signal from the signal (E) that is the IF signal. At this time, the propagation path phase information θ 1 of the signal of the path 1 is also canceled out. Similarly, the propagation path phase information Θ 3 of the signal of the path 3 is also canceled.

[0024] Radio signals (including propagation path phase information 0 2 and 0 4) received by the reception antenna 21b of the radio reception device 20 are amplified by the amplifier 22b, and then are local oscillators in the multiplier 23b. It is mixed with 24 reference signals and converted to an IF signal. It is input to the distributor 27b via the filter 25b and the variable amplifier 26b. This IF signal is distributed to the modulated signal branch and the pilot branch by the distributor 27b, and is input to the quadrature demodulator 29b via the delay corrector 28b in the modulated signal branch. In the pilot branch, the pilot signal is extracted by the band pass filter 30b, amplified by the amplifier 31b, and then input to the quadrature demodulator 29b.

[0025] The quadrature demodulator 29b cancels the phase noise by subtracting (E−F) the signal (F) that is the pilot signal from the signal (E) that is the IF signal. At this time, the propagation path phase information Θ 2 of the signal of path 2 is also canceled. Similarly, the propagation path phase information Θ 4 of the signal of the path 4 is also canceled.

[0026] Thus, since the propagation path phase information 0 1, 0 2, Θ 3, and Θ 4 of the signal input to the MIMO synthesizer 32 have been lost, the MIMO synthesizer 32 performs the MIMO matrix operation. As a result, it becomes impossible to separate multiple data sequences, and it becomes impossible to output a signal to the reception baseband unit (reception BB unit) 33.

[0027] An object of the present invention is to provide a wireless transmission device, a wireless reception device, and a wireless communication system capable of realizing both a phase noise cancellation function and a MIMO communication function. Means for solving the problem

[0028] A wireless reception device of the present invention is a wireless reception device of a wireless communication system that performs n systems (n is a plurality) of MIMO communications, and in a wireless transmission device of a communication partner, among the n systems of MIMO paths A pilot means is superimposed on an arbitrary m system (m is a natural number, n> m), receiving means for receiving signals transmitted by multiple systems, received signal power, extracting means for extracting the pilot signals, and all And a plurality of orthogonal demodulation means for performing orthogonal demodulation on the received signal transmitted through the MIMO path using the extracted pilot signal.

[0029] A radio transmission apparatus according to the present invention includes a separating unit that separates a transmission signal into n MIMO paths, a pilot signal generating unit that generates a pilot signal, and the pilot signal superimposed on m of the n systems. A superimposing means for transmitting and a transmitting means for transmitting signals to the radio receiving apparatus in n systems.

[0030] The wireless communication system of the present invention is a wireless transmission device using n systems (n is a plurality) of MIMO communications. A wireless communication system for transmitting a signal to a wireless reception device, wherein the wireless transmission device includes a separation unit that separates a transmission signal into n MIMO paths, a pilot signal generation unit that generates a pilot signal, A superimposing unit that superimposes a pilot signal on m systems (m is a natural number, n> m) of the n systems, and a transmitting unit that transmits signals to the wireless receiving apparatus in n systems. An apparatus includes: a receiving unit that receives a signal transmitted from a wireless transmission device of a communication partner; an extracting unit that extracts the pilot signal from the received signal; and the extraction for the received signal transmitted through all MIMO paths. And a plurality of orthogonal demodulation means for performing orthogonal demodulation using the pilot signal thus obtained.

The invention's effect

[0031] According to the present invention, the wireless transmission device superimposes the pilot signal for phase noise cancellation on only one of the propagation paths of a plurality of systems, and the wireless reception device extracts By using the signal for quadrature demodulation of the signals of all propagation paths, the phase information of the propagation path is not lost during quadrature demodulation, so the phase noise cancellation function and the MIMO communication function can be realized together. Good communication characteristics can be obtained.

Brief Description of Drawings

FIG. 1 is a block diagram showing an example of a wireless receiving device in a conventional wireless communication system

FIG. 2 is a characteristic diagram showing frequency characteristics of each component of the local noise canceller in the wireless receiver of FIG.

FIG. 3 is a block diagram showing a configuration of a wireless transmission device and a wireless reception device when phase noise cancellation technology is applied during MIMO communication in a conventional wireless communication system.

FIG. 4 is a block diagram showing configurations of a wireless transmission device and a wireless reception device of the wireless communication system according to Embodiment 1 of the present invention.

FIG. 5 is a block diagram showing configurations of a wireless transmission device and a wireless reception device of the wireless communication system according to Embodiment 2 of the present invention.

FIG. 6 is a block diagram showing configurations of a wireless transmission device and a wireless reception device of the wireless communication system according to the third embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the wireless communication system of the present invention will be described in detail. Note that, in the drawings used in the following embodiments, the same components are denoted by the same reference numerals, and redundant description is omitted.

FIG. 4 is a block diagram showing configurations of radio transmitting apparatus 100 and radio receiving apparatus 200 of the radio communication system according to Embodiment 1 of the present invention. The wireless communication system shown in Fig. 4 shows a case where communication is performed by two systems of MIMO for easy understanding.

Radio transmission apparatus 100 includes transmission baseband unit (transmission BB unit) 101, MIMO separation unit 102, orthogonal modulation units 103a and 103b, pilot signal generation unit 104, adder 105a, local oscillator 106, transmission RF unit 107a and 107b and transmission antennas 108a and 108b are provided.

On the other hand, radio receiving apparatus 200 includes receiving antennas 201a and 201b, amplifiers 202a and 202b, local oscillator 203, multipliers 204a and 204b, bandpass filters 205a and 205b, variable amplifiers 206a and 206b, and a first distribution. 207, delay correctors 208a and 208b, quadrature demodulation units 209a and 209b, band pass filter 210, amplifier 211, second distributor 212, MIMO synthesis unit 213, and reception baseband unit (reception BB unit) 214.

In radio transmission apparatus 100, transmission BB section 101 generates a baseband signal and outputs it to Ml MO separation section 102. MIMO separation section 102 separates the baseband signal into two systems. Quadrature modulation sections 103a and 103b perform quadrature modulation on each baseband signal separated into two systems.

[0038] Pilot signal generation section 104 generates a pilot signal for phase noise cancellation. Adder 105a mixes the pilot signal with the modulation signal output from quadrature modulation section 103a.

[0039] The local oscillator 106 generates a local oscillation signal (local signal) and outputs it to the transmission RF units 107a and 107b. The transmission RF units 107a and 107b frequency-convert the modulation signal into a radio signal (RF signal) using the input local oscillation signal. The transmitting antennas 108a and 108b transmit radio signals to the wireless receiving device 200.

[0040] The radio signal transmitted from the transmitting antenna 108a is transmitted through the path 1 to the propagation path phase information.

When it is received by the receiving antenna 201a of the wireless receiving device 200 with θ1 added. In addition, the signal is received by the receiving antenna 201b of the radio receiving apparatus 200 through the path 2 with the propagation path phase information Θ 2 added thereto. In addition, the radio signal transmitted from the transmission antenna 108b is received by the reception antenna 201a of the radio reception device 200 via the path 3 with the propagation path phase information Θ3 added, and via the path 4. Thus, the signal is received by the receiving antenna 201b of the radio receiving apparatus 200 with the propagation path phase information Θ 4 added.

Next, in radio receiving apparatus 200, receiving antenna 201 a receives a radio signal to which propagation path phase information θ 1 has been added via path 1, and propagates path phase information via path 3. A radio signal with Θ 3 added is received. In addition, the receiving antenna 201b receives a radio signal to which the propagation path phase information Θ2 is added via the path 2, and receives a radio signal to which the propagation path phase information Θ4 is added via the path 4. To do.

The amplifiers 202a and 202b amplify the radio signals received by the respective receiving antennas 201a and 201b. The local oscillator 203 generates a local oscillation signal (local signal) and outputs it to the multipliers 204a and 204b. Multipliers 204a and 204b frequency-convert radio signals (RF signals) received from the respective amplifiers 202a and 202b into IF signals using the local transmission signals from local transmitter 203.

[0043] The band pass filters 205a and 205b extract only signals in a desired frequency band with the signal power frequency-converted by the multipliers 204a and 204b, respectively. The variable amplifiers 206a and 206b variably amplify signals in desired frequency bands output from the band pass filters 205a and 205b, respectively.

[0044] The first distributor 207 distributes the signal output from the variable amplifier 206a in two directions, ie, a modulated signal branch and a pilot branch. The band pass filter 210 extracts a pilot signal from the signal distributed to the pilot branch by the first distributor 207 and outputs it to the amplifier 211. The amplifier 211 amplifies the pilot signal extracted by the band pass filter 210 and outputs it to the second distributor 212. The second distributor 212 distributes the pilot signal output from the amplifier 211 to two systems and outputs it to the quadrature demodulator 209a and the quadrature demodulator 209b.

[0045] Delay corrector 208a delays the modulated signal of the modulated signal branch distributed by first distributor 207, and outputs the delayed signal to quadrature demodulator 209a. Quadrature demodulator 209a uses the second distribution The pilot signal output from the unit 212 and the output signal from the delay corrector 208a are frequency-multiplied and subjected to quadrature demodulation. That is, the quadrature demodulator 209a converts the pilot signal corresponding to the propagation path phase information θ 1 into the signal to which the propagation path phase information θ 1 of the path 1 is added and the signal to which the propagation path phase information Θ 3 of the path 3 is added. Quadrature demodulation is performed by multiplying each frequency.

[0046] Delay corrector 208b gives a delay to the modulated signal output from variable amplifier 206b and outputs the delayed signal to quadrature demodulator 209b. The orthogonal demodulator 209b multiplies the pilot signal distributed by the second distributor 212 and the output signal from the delay corrector 208b by frequency, and performs orthogonal demodulation. That is, the orthogonal demodulation unit 209b adds the pilot signal corresponding to the propagation path phase information θ 1 to the signal to which the propagation path phase information Θ 2 of path 2 is added and the propagation path phase information Θ 4 of path 4 Each signal is orthogonally demodulated by frequency multiplication.

As a result, the phase noise of the local oscillator is canceled in the signal of each propagation path after quadrature demodulation. In addition, the absolute value of the propagation path phase information of each propagation path signal after quadrature demodulation changes, but the relative relationship does not change. That is, the propagation path phase information of the signal of path 1 is θ 1-Θ 1 = 0, the propagation path phase information of the signal of path 2 is 0 2− 0 1, and the propagation path phase information of the signal of path 3 is , 0 3 — 0 1, and the propagation path phase information of the signal of path 4 is Θ 4 −θ 1.

[0048] MIMO combining section 213 uses the path 1 signal and path 3 signal output from quadrature demodulation section 209a, and the path 2 signal and path 4 signal output from quadrature demodulation section 209b to form a matrix. The calculation is performed, and the two baseband signals obtained are serialized (MIMO synthesis) and output to the reception baseband unit 214. The reception baseband unit (reception BB unit) 21 4 converts the baseband signal output from the MIMO synthesis unit 213 and outputs the converted signal to a circuit in a subsequent process.

Next, operations of radio transmitting apparatus 100 and radio receiving apparatus 200 of the radio communication system shown in FIG. 4 will be described.

[0050] The baseband signal output from the transmission BB unit 101 of the wireless transmission device 100 is separated into two systems by the MIMO separation unit 102. Further, the separated baseband signals are orthogonally modulated by the orthogonal modulators 103a and 103b, respectively. [0051] Next, in adder 105a, the phase noise canceling pilot signal generated by pilot signal generating section 104 is superimposed on the modulated signal output from quadrature modulator 103a. Next, in transmission RF section 107a, the modulated signal on which the pilot signal is superimposed is converted into a radio signal (RF signal) and transmitted from transmission antenna 108a. Also, in the transmission RF section 107b, the modulated signal output from the quadrature modulator 103b is converted into a radio signal (RF signal) and transmitted from the transmission antenna 108b.

[0052] Thereby, the radio signal transmitted from the transmission antenna 108a of the radio transmission apparatus 100 is received by the reception antenna 201a of the radio reception apparatus 200 with the propagation path phase information θ1 added via the path 1. Then, the propagation path phase information Θ 2 is added via the path 2 and received by the reception antenna 201b of the radio reception apparatus 200. Further, the radio signal transmitted from the transmission antenna 108b of the wireless transmission device 100 is received by the reception antenna 201a of the wireless reception device 200 through the path 3 with the propagation path phase information Θ3 added thereto, and is transmitted through the path 4. Thus, the propagation path phase information Θ 4 is added and received by the reception antenna 201b of the radio reception apparatus 200.

[0053] The radio signal of path 1 (propagation phase information θ 1) and the radio signal of path 3 (propagation phase information Θ 3) received by the receiving antenna 201a are amplified by the amplifier 202a and then locally oscillated. The frequency is converted by the multiplier 204a using the local oscillation signal of the unit 203, only the component of the desired frequency band is extracted by the band pass filter 205a, and is variably amplified by the variable amplifier 206a. In addition, the radio signal of the path 2 (propagation phase information Θ 2) and the radio signal of the path 4 (propagation phase information Θ 4) received by the receiving antenna 201b are amplified by the amplifier 202b and then the local oscillator 203 The frequency is converted by the multiplier 204b using the local oscillation signal, only the component of the desired frequency band is extracted by the band pass filter 205b, and variably amplified by the variable amplifier 206b.

[0054] In the first distributor 207, the signal output from the variable amplifier 206a is distributed in two directions of the modulated signal branch and the pilot branch. In the band pass filter 210, the pilot signal including the propagation path phase information Θ 1 of the path 1 is extracted from the signal power distributed to the pilot branch. The pilot signal is amplified by the amplifier 211, distributed to two systems by the second distributor 212, and input to the quadrature demodulator 209a and the quadrature demodulator 209b.

[0055] The signal distributed to the modulation signal branch is delayed by the delay corrector 208a, Input to the demodulator 209a. The signal output from the variable amplifier 206b is delayed by the delay corrector 208b and input to the quadrature demodulator 209b.

[0056] The quadrature demodulator 209a uses the pilot signal corresponding to the propagation path phase information θ1, and uses the pilot signal corresponding to the propagation path phase information θ1 and the wireless signal of the path 3 (propagation phase information θ1) Quadrature demodulation is performed for 3). Further, the quadrature demodulator 209b uses the pilot signal corresponding to the propagation path phase information θ 1 and uses the pilot signal corresponding to the propagation path phase information θ 1 and the wireless signal of the path 4 (propagation phase information Θ 2) and the wireless signal of the path 4 (propagation phase information Θ 4 ) Is subjected to quadrature demodulation.

Therefore, the MIMO combining unit 213 receives the signal of the path 1 (propagation phase information 0 1− 0 1 = 0) output from the quadrature demodulation unit 209a and the signal of the path 3 (propagation phase information Θ 3 — Θ 1) is input, and the signal of path 2 (propagation phase information η θ 2-θ 1) and the signal of path 4 (propagation phase information Θ 4 θ 1) output from the quadrature demodulator 209b Entered. The synthesizing unit 213 performs matrix calculation using these signals. The two baseband signals obtained by the matrix operation are serialized by the synthesizer 213 and converted by the receiver 213.

As described above, according to the present embodiment, in radio reception apparatus 200, all received radio signals (propagation paths) using the pilot signal containing the propagation path phase information of one propagation path are used. By performing quadrature demodulation of the phase information (Θ1, Θ2, Θ3, Θ4), the phase noise of the local oscillator can be canceled and the relative relationship of the transmission path phase information of each propagation path is changed. Because there is no 行列 matrix operation can be performed.

In the second embodiment, pilot signals are extracted from a plurality of reception systems, and signals of all paths are orthogonally demodulated using the extracted pilot signals having the highest signal level.

[0060] FIG. 5 is a block diagram showing configurations of radio transmitting apparatus 100 and radio receiving apparatus 200a of the radio communication system according to Embodiment 2 of the present invention. A radio reception apparatus 200a shown in FIG. 5 is provided with a first distributor 207a, a bandpass filter 210a and an amplifier 21la in one reception system, and a first distributor 207b, a bandpass filter 210b and an amplifier in the other reception system. Provide a width 21 lb. Further, the wireless reception device 200a includes the wireless reception device 200 shown in FIG. In contrast, a configuration in which a comparator 215 is added is adopted.

[0061] The first distributor 207a distributes the signal output from the variable amplifier 206a in two directions, ie, a modulated signal branch and a pilot branch. The band pass filter 210a extracts the pilot signal from the signal distributed to the pilot branch by the first distributor 207a and outputs it to the amplifier 21 la. The amplifier 21 la amplifies the pilot signal extracted by the band pass filter 210 a and outputs it to the comparator 215.

[0062] The first distributor 207b distributes the signal output from the variable amplifier 206b in two directions of a modulated signal branch and a pilot branch. The band pass filter 210b extracts a pilot signal from the signal distributed to the pilot branch by the first distributor 207b and outputs it to the amplifier 21 lb. The amplifier 21 lb amplifies the pilot signal extracted by the band pass filter 210b and outputs the amplified signal to the comparator 215.

[0063] Comparator 215 compares the signal level of the pilot signal output from amplifier 21 la with the signal level of the pilot signal output from amplifier 21 1 lb, and determines the pilot signal having the higher signal level as the first signal. 2 Outputs to the distributor 212. As a result, the pilot signal having the better quality is supplied to the orthogonal demodulation unit 209a and the orthogonal demodulation unit 209b.

As a result, according to the present embodiment, since it is possible to perform quadrature demodulation of all propagation paths using a pilot signal with good quality, a more accurate phase noise cancellation function and MIMO separation function Can be realized.

In the third embodiment, a transmission path on which a pilot signal is superimposed is determined based on downlink propagation path information such as a subcarrier signal level of frequencies around the pilot signal.

FIG. 6 is a block diagram showing configurations of radio transmitting apparatus 100a and radio receiving apparatus 200a of the radio communication system according to Embodiment 3 of the present invention. The radio transmission device 100a shown in FIG. 6 is provided with adders 105a and 105b in each transmission system. 6 employs a configuration in which a determination unit 109 and a switch 110 are added to the wireless transmission device 100 illustrated in FIG. 4 and FIG. In FIG. 6, the radio receiving device 200a may have the same configuration as the radio receiving device 200 shown in FIG.

[0067] The determination unit 109 constantly monitors the spatial propagation state of the downlink propagation path and monitors the subcarrier signal level. The information indicating the determination result is output to the switch 110. Based on the determination result of the determination unit 109, the switch 110 outputs the pilot signal generated by the pilot signal generation unit 104 to either the adder 105a or the adder 105b.

[0068] As described above, in the present embodiment, the phase noise cancellation function and the MIMO communication function are optimally switched by switching the propagation path on which the pilot signal is superimposed to the optimal path according to the spatial propagation state. It can be realized together.

[0069] Note that, in each of the above-described embodiments, the power of the present invention described for two systems of MIMO communication is not limited to this, and can also be applied to three or more systems of MIMO communication. In addition, in the two-channel MIMO communication, the case where the pilot signal is superimposed on one system has been described. However, the present invention is not limited to this. For example, in the four-channel MIMO communication, the pilot signal is superimposed on two systems. In the case of n systems (n is a multiple number) of MIMO communication, this can also be applied to the case where pilot signals are superimposed on m systems (m is a natural number, n> m).

The present invention can also be applied to an apparatus having a direct conversion configuration, and can also be applied to an apparatus having a Low-IF configuration.

[0071] The present invention II can also be applied to multicarrier communication such as OFDM (Orthogonal Frequency Division Multiplexing). By superimposing a pilot in the center of the band of the OFDM signal, all phases in the transmission path can be obtained. Noise can be canceled out.

Industrial applicability

[0072] Since the present invention can improve the phase noise characteristics while performing MIMO communication, it is suitable for use in various wireless communication devices such as mobile phones, PHS, wireless LANs, etc. It is.

Claims

The scope of the claims

[1] A wireless receiving device of a wireless communication system that performs n systems (n is a multiple number) of MIMO communications, and communicates with the wireless transmission device of the communication partner. Any m systems (m Is a natural number, n> m) with a pilot signal superimposed and receiving means for receiving signals transmitted by multiple systems,

Extracting means for extracting the pilot signal from the received signal;

A plurality of orthogonal demodulation means for performing orthogonal demodulation using the extracted pilot signals for the received signals transmitted in all MIMO paths;

A wireless receiver comprising:

[2] A wireless receiver of a wireless communication system that performs MIMO communication of multiple systems,

In the wireless transmission device of the communication partner, a pilot signal is superimposed on an arbitrary one of a plurality of MIMO paths, receiving means for receiving a signal transmitted by the plurality of systems, and extraction for extracting the pilot signal from the received signal Means,

A wireless receiver comprising:

[3] The extraction means extracts the pilot signals from the received signals of a plurality of MIMO paths,

Comparing means for comparing the signal level of the pilot signal and outputting the pilot signal having the highest signal level to the quadrature demodulating means,

The wireless receiver according to claim 1.

[4] separation means for separating the transmission signal into n MIMO paths;

Pilot signal generating means for generating a pilot signal;

A radio transmission apparatus comprising: superimposing means for superimposing the pilot signal on m systems out of the n systems; and transmitting means for transmitting signals in n systems to the radio reception apparatus according to claim 1.

[5] A determination means for determining whether the spatial propagation state of each MIMO path is good or bad is provided. The superimposing means switches the system for superimposing the pilot signal based on the determination result of the determining means.

The wireless transmission device according to claim 4.

A wireless communication system that transmits a signal from a wireless transmission device to a wireless reception device by n systems (n is a plurality) of MIMO communication,

The wireless transmission device

Separation means for separating the transmission signal into n MIMO paths;

Pilot signal generating means for generating a pilot signal;

A superimposing means for superimposing the pilot signal on m of the n systems (m is a natural number, n> m);

Transmitting means for transmitting signals to the wireless reception device in n systems, the wireless reception device,

Receiving means for receiving a signal transmitted from a wireless transmission device of a communication partner; extracting means for extracting the pilot signal from the received signal;

A plurality of orthogonal demodulation means for performing orthogonal demodulation using the extracted pilot signals for the received signals transmitted through all MIMO paths,

Wireless communication system.