JPS6313430A - Repeating installation for digital radiocommunication - Google Patents

Abstract

PURPOSE:To eliminate the leaking at the same frequency band, to increase a communication capacity and to improve the using efficiency of a frequency by inserting a pilot signal into a transmitting signal, detecting this at a receiving side and removing an interference wave component in the signal. CONSTITUTION:By modulation demodulation circuits 10 and 20 at a transmitting side of a relaying device, pilot signals f+1 and f-1 are respectively inserted. Consequently, when transmitting signals T2 and T1 are leaked into a receiving signal R1, the phase and amplitude of the pilot signals f+1 and f-1 are detected at a detecting circuit 1 of a compensating circuit 30 by the synchronizing detection. At a control circuit 2 of the compensating circuit 30, further, the transmitting signals T2 and T1, which are the interference wave components, are controlled so as to come to be the same amplitude with the phase reverse to the phase detected by the synchronizing detection. The controlled signal is synthesized to a receiving signal R1 and the interference wave component is removed. Thus, the leaking signal from the transmitting side to the receiving side in the same repeating installation can be cancelled. By inserting the pilot signal into a transmitting signal, detecting this at the receiving side and removing the interference wave component in the signal, the leaking-in at the same frequency band is eliminated, the communication capacity can be increased and the using efficiency of the frequency can be improved.

Description

[Detailed Description of the Invention] [Summary] The present invention provides a method for canceling leakage signals from the transmitting side to the receiving side at the same repeater, which is a problem in wireless communication systems that relay the same frequency band. Insert a pilot signal into the transmitted signal, detect the pilot signal on the receiving side,
This is used to cancel out the leaking interference wave components and enable transmission in the same frequency band.

[Industrial application field]

TECHNICAL FIELD The present invention relates to wireless communication systems, and particularly to improvements in relay devices for digital wireless communication systems.

In the field of digital wireless communications, multilevel modulation/demodulation methods such as 16QAM, 64QAM, and 256QAM, co-channel transmission methods, etc. are being developed to improve the efficiency of frequency use.
A relay system for the same frequency band is being considered. That is, when the same frequency band relay method is used, since the frequency band for transmission and reception is the same, the communication capacity can be simply doubled compared to a method that uses different frequencies for transmission and reception.

[Conventional technology]

A schematic configuration of a conventional wireless communication system is shown in FIG. 5, where a bidirectional repeater (RP) 100 is connected to one side (uplink).
The received signal R1 from the other side (downlink) is sent out as one transmission signal T2 via the reception circuit (RXl) 40, the modulation/demodulation circuit (MODEMI) 10, and the transmission circuit (TXI) 50, and the reception signal R2 from the other side (downlink) is sent out as one transmission signal T2. Receiving circuit (RX2
) 60, a modulation/demodulation circuit (MODEM2) 20, and a transmission circuit (TX2) 70 to be sent out as the other transmission signal T1.

In this conventional relay system, signal transmission is performed by changing the transmitting and receiving frequency bands.

[Problem that the invention seeks to solve]

Now, if the conventional repeater 100 shown in FIG. 5 is applied as is to the above-mentioned repeating system using the same frequency band (receiving frequency fo), for example, the received signal R1 includes the uplink transmission signal T2, which has a high signal level, and the downlink transmission signal T2, which has a high signal level. Leakage occurs from the transmission signal T1 of the line, and the reception signal R1 with a low signal level is sent to a predetermined D/U (Desired/υndesired).
It becomes much more difficult to obtain the signal ratio. This becomes more difficult as the modulation and demodulation of the lawn grows.

Therefore, in such a relay system, a large burden is placed on isolation of antennas between transmitting and receiving, system gain, etc., and strict characteristics are required in system design, resulting in an increase in cost.

Therefore, an object of the present invention is to provide a relay device for digital wireless communication that can cancel self-interference between transmitting and receiving in the same frequency band relaying system.

[Means for solving problems]

FIG. 1 shows a principle diagram of a relay device for digital wireless communication that transmits and receives signals in the same frequency band according to the present invention, and this relay device includes pilot carrier signals f, I and Modulation and demodulation circuit 1 that inserts f-+ (or f, l and f, or f and f -1)
0 and 20, and pilot carrier signals r, l, and r- leaked from the transmitting side into the received signal R1 (or R2) on the receiving side.
+ (or r, 1 and T0 or f, and f-1) and detect pilot carrier signals f, 1 and f-1 (or f
, , T0 or f, and a compensation circuit (30) for canceling interference wave components in the received signal R1 (or R2) corresponding to r-1). Here, T6, f, f
-I are signals of different frequencies at the center of the same band.

In a preferred embodiment, the compensation circuit 30 converts the received signal R1 (or R2) to the pilot carrier signal r, as shown in block diagram form in FIG. 1 and f-3 (or f., T0 or f,
and f-1), a control circuit 2 that generates a compensation signal that controls the transmission signals T2 and T1 to have the same amplitude and the opposite phase as the interference wave component contained in the received signal R1 (or R2), and this compensation signal. and an adder circuit 3 that combines the received signal R1 (or R2) and the received signal R1 (or R2).

[For production]

In FIGS. 1 and 2, pyro-/) signals f, ,
and f-+ (or f, 1 and T0 or fo and f-5
). Therefore, if the transmitted signals T2 and T1 leak into the received signal R1 (or R2), the pilot signals [, , and f-3 (or f, I and T0 or f
o and f-3) are detected by the detection circuit l of the compensation circuit 30 by synchronous detection. The control circuit 2 of the compensation circuit 30 further transmits transmission signals T2 and T which are interference wave components.
l is controlled so that it has the same amplitude at an opposite phase to the phase detected by synchronous detection. Then, this controlled signal is combined with the received signal R1 (or R2) and its interference wave component is removed.

〔Example〕

FIG. 3 shows an embodiment of the digital wireless communication relay device of the present invention conceptually shown in FIGS. 1 and 2. A compensation circuit 31 that compensates for leakage, that is, interference waves, and a compensation circuit 32 that compensates for leakage of the downlink transmission signal T1, that is, interference waves (the circuit content is omitted because it has the same configuration as compensation circuit 31). , is composed of.

That is, in the compensation circuit 31, the detection circuit 1 of FIG.
A distributor 11 that orthogonally distributes the local signal in the modulation/demodulation circuit 10 that generates the transmission signal T2, and a synchronous detector 12.13 that synchronously detects the received signal R1 using the two orthogonal signals r and Q of the distributor 11. It is comprised of low-pass filters 14.15 that filter each of these outputs, and an arithmetic circuit 16 that performs predetermined calculations from the outputs of these low-pass filters 14.15. The control circuit 2 also has a phase control circuit 21 and an amplitude control circuit 21.
It consists of an S circuit 22.

Note that the local signals from the modulation/demodulation circuits 1o and 20 of the transmission signal TIT2 are local oscillation signals before being modulated.

Here, the state of use of the pilot carrier signal will be explained with reference to FIG. +(fc +Δf,) and inserted into the transmission signal and transmitted. These pilot carrier signals f and l are received by the relay device 102 and are further converted into another pilot carrier signal f− in the modulation/demodulation circuit within the relay device 102.

(re-Δf1). This pilot signal f
-, is converted into the first pilot carrier signal f0 in the modulation/demodulation circuit within the repeater 103. Therefore, 3 pylons) 1! It is sufficient to prepare a transmission signal. Note that Δf1 and Δf2 do not need to have the same frequency width, and are much smaller than the signal bandwidth.

Next, the operation in the embodiment shown in FIG. 3 will be explained.

In the compensation circuit 31, the pilot signal f, which is a local oscillation signal of the transmission signal T2, is divided into an in-phase component and a quadrature component by a distributor 11, and the divided components are sent to the synchronous detection circuits 12 and 13.

The synchronous detection circuits 12.13 detect the pilot signal r from the received signal R1 and send it to the arithmetic circuit 16 via the low-pass filters 14.15.

The arithmetic circuit 16 calculates the amplitude (IN+Q,)""=r and the phase jan-'(I x
/Qy)-θ is calculated.

Using this calculation result, the phase control circuit 21 outputs the transmission signal T2.
The phase of the signal is controlled to -θ, and the amplitude is controlled to r by the amplitude control circuit 22. Therefore, by combining the output signal of the control circuit 2 with the received signal R1 in the adder circuit 3, it is possible to remove the interference wave component accompanying the pilot signal L+ in the received signal R1.

A similar operation is performed in the compensation circuit 32 for the received signal R1 and the transmitted signal T1.

In addition, in the above explanation, the received signal R1, the transmitted signals T2, T1
The explanation was given using the example, but the received signal R2, the transmitted signal T1
, T2, and for the received signal R2,
A compensation signal can be obtained by using a circuit similar to that shown in FIG. Accordingly, compensation circuit 30 in FIG. 1 is shown as compensating for interference in both received signals R1 and R2.

In this way, leakage signals from the transmitting side to the receiving side can be canceled in the same relay device.

〔Effect of the invention〕

As described above, according to the present invention, the interference wave component in the received signal is removed by inserting a pilot signal into the transmitted signal and detecting it on the receiving side. There is no problem of leakage, and the effect is that communication capacity can be increased and frequency utilization efficiency can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a principle diagram of a digital wireless communication relay device according to the present invention, FIG. 2 is a block diagram conceptually showing a preferred embodiment of the relay device in FIG. 1, and FIG. 3 is a digital wireless communication relay device according to the present invention. A block diagram showing an embodiment of a communication relay device, FIG. 4 is a diagram showing a plurality of relay devices of the present invention and each received signal to explain changes in pilot signals, and FIG. 5 is a diagram showing a conventional wireless communication system. FIG. 1 to 3, 10.20 is a modulation/demodulation circuit (MODEM), 30 is a compensation circuit (CC), 1 is a detection circuit, 2 is a control circuit, 3 is an addition circuit, 4 is a demodulation circuit, 31.32 12 and 13 are compensation circuits for each interference wave, 12 and 13 are synchronous detection circuits, 16 is an arithmetic circuit, 21 is a phase control circuit, and 22 is an amplitude control circuit. In the drawings, the same reference numerals indicate the same or corresponding parts. Patent applicant Fujitsu Ltd. Representative Patent Attorney Mori 1) Hiroshi (1 other person) Uninvented 9
Fig. 1: Principle diagram of the joint device Fig. 5: Block diagram of the conventional medium W

Claims (5)

[Claims] (1) In a digital wireless communication relay device that transmits and receives signals in the same frequency band, a modulation/demodulation circuit (10, 20 ), and the pilot carrier signals (f_0, f_+_1,
f_-_1) is synchronously detected to detect the pilot carrier signal (
A relay device for digital wireless communication, comprising: a compensation circuit (30) for canceling interference wave components in the received signals (R1, R2) corresponding to signals (f_0, f_+_1, f_-_1). (2) The compensation circuit (30) receives the received signal (R1,
R2) to the pilot carrier signal (f_0, f_+_
1, f_−_1), and a detection circuit (1) that synchronously detects the synchronously detected pilot carrier signal (f_0, f_+
The received signal (R1, R2
), a control circuit (2) that generates a compensation signal that controls the transmission signal (Ti, T2) to have the same amplitude and opposite phase as the interference wave component contained in the interference wave component contained in the compensation signal and the reception signal (R1, R
2). The digital wireless communication relay device according to claim 1, comprising: an adding circuit (3) for combining (3) The detection circuit (1) detects the transmission signals (T1, T
2) based on the local signal of the pilot carrier signal (
a demodulation circuit (4) for extracting in-phase and quadrature components of f_0, f_+_1, f_-_1); and an arithmetic circuit (4) for determining the phase and amplitude of the transmission signal from the in-phase and quadrature components.
16) The digital wireless communication relay device according to claim 2, comprising: (4) The received signal (R1, R2) consists of the received signal (R1) from the uplink and the received signal (R2) from the downlink, and the compensation circuit (30) The digital radio according to any one of claims 1 to 3, which includes a compensation circuit (31, 32) using each of the downlink transmission signal (T2) and the downlink transmission signal (T1) as interference wave sources. Communication relay device. (5) The modulation/demodulation circuit (10, 20) inserts the first pilot carrier signal (f0) inserted into the received signal (R1) from the uplink into the same uplink transmission signal (T1). A first modulation/demodulation circuit (10) converts the first pilot carrier signal (f_c) into a second pilot carrier signal (f_+_1) and converts the first pilot carrier signal (f_c) inserted into the received signal (R2) from the downlink to the second pilot carrier signal (f_+_1). A digital radio according to claim 4, comprising: a second modulation/demodulation circuit (20) that converts into a third pilot carrier signal (f_-_1) to be inserted into the transmission signal (T1); Communication relay device.