JPH03179820A - Transmission equipment in single frequency communication system - Google Patents

Abstract

PURPOSE:To attain miniaturization, light-weight and low power consumption by providing a characteristic to cancel the distortion due to the characteristic of a propagation channel to a signal in advance in response to the characteristic of a radio propagation channel detected by a reception signal to reduce the circuit scale or the like of a mobile station. CONSTITUTION:A radio base station is provided with a device 15, which detects the characteristic of a propagation channel on the condition that transmission reception are implemented in time division by using the same frequency in the radio base station 1 and a mobile station 2. Then an equalizer 17 is provided, which has a characteristic to cancel the distortion possibly caused by the characteristic of the propagation channel in response to the characteristic of the propagation channel detected thereby and the equalizer 17 applies equalization to the transmission signal at the radio base station 1 in the transmission timing from the radio base station 1 to the mobile station 2. Thus, the equalizing means with less load on the mobile station 2 is realized and the system is applied to the portable mobile station requiring small size and light weight.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a mobile communication system in which radio base stations and mobile stations perform time-divisional transmission using a single carrier frequency, and particularly relates to a mobile communication system in which transmission quality is The present invention relates to a mobile communication system in which an equalizer is applied to a modulation baseband signal as a means for improving the modulation baseband signal.

[Conventional technology]

In digital mobile communication, when high-speed signal transmission is carried out, selectivity 7enong occurs due to propagation delay time dispersion, and propagation characteristics are significantly deteriorated, which poses a problem.

As a countermeasure against this problem, it is well known that applying an equalizer on the receiving side is effective.

FIG. 4 is a diagram showing an example of a device MIr& using a conventional reception equalizer in a single frequency communication system,
a indicates a wireless base station, 50b indicates a mobile station, and 51a
, 51b is a transmitter, 52a and 52b are receivers, 56
a, 56b are antenna switching devices, 55a, 55b are propagation path characteristic detectors, 54a, 54b are control devices that control each of the above devices, 53a, 53b are antennas, 57a*57b
represents an equalizer that equalizes the distortion of the received signal.

Since both the radio base station 50a and the mobile station 50b are basically constructed of the same device and operate in the same way, only the base station will be described here.

In the figure, a transmitter 51a and a receiver 52a use the same frequency. Therefore, the antenna switch 56m connects the transmitter 51a to the antenna 53a during transmission, and connects the receiver 52a to the antenna 53a during reception. The propagation path characteristic detector 55a detects the characteristics of the propagation path from the received signal, and based on the detected characteristic, the equal volumetric capacity 57a operates to remove distortion added to the received signal.

As a constant volume, delay circuits 58-1 to 58-1 as shown in FIG.
When a transversal equalizer consisting of adders 59-1 to 59-n1 and 60 is used, equalization is performed after calculating isovolume tap coefficients from the received signal.

[Problem to be solved by the invention]

Figure 6 shows a propagation path characteristic detector (
55g or 55b) in FIG. 4 and a diagram showing an example of the detection principle, (a) is the MR factor, (b)
) to (e) show each component of the correlation detection output, and 6
1 represents a correlation detector, and 62 represents a PN signal generator.

In the figure, let D (t) be a signal with signal delay received via multiple propagation paths.

Further, let I(1) be the in-phase component of the output of the correlation detector 61, and let Q(t) be the orthogonal component.

Let the amplitudes of I(t) and C/Q(t) at time A'J t j be iJ and c/Qj, +D (tJ
) I =F'A1]b1, and its phase angle is j
an-' (Qj/Ij).

In addition to this, the propagation path characteristics can be determined from the level and phase of the delayed wave at time tj.

On the actual ship, isovolume tap coefficients are set based on this information, and the received signal is equalized.

The transversal isovolume transfer function is H(z) =
h,)+ +l, z-'10h 2 z-2+-...
=+h, 1-, 1n-1・・・・・・・・・・・・
・Given by (1).

To simplify the explanation, we will explain the case where there is a main wave and one delayed wave as received waves.If the delay time of the delayed wave is set, the main wave and i! i! When the level ratio of the spread wave is T,
The transfer function of the propagation path is C(z)=10T2−K ・
・・・・・・・・・・・・ It is given by (2).

The isovolume is (2) Also equalizes It is, (2> = 1 /C (7) (3) There is Tohojo rp'r.

By doing so, the tap coefficient hk is given.

Note that T is given as T=l D21/I D,I from the signal obtained by the aforementioned propagation path characteristic detector.

Also, it is given by the time interval between and D2. In reality, T and will vary depending on the seven aeons, but
Equalization is possible by transmitting a training signal at least once within the fluctuation period.

Tap coefficients can be found in the same manner even when a plurality of delayed waves exist. Further, even when the types of isovolumes are different, tap coefficients can be obtained, although there are some differences.

As described above, equalization processing is complex and requires a large processing system, so it has traditionally been difficult to apply it to portable mobile devices that require small size and light weight11. There were problems such as a long processing time.

In view of these conventional problems, it is an object of the present invention to provide an equalization means that reduces the burden on the movable shore.

[Means to solve the problem]

According to the invention, the above-mentioned object is achieved according to said patent al'! The person is a distant relative by the means specified in the scope of the request.

That is, the present invention provides a non-IT device configured such that a transmitter and a receiver that use the same frequency switch and use the same antenna, which is equipped with means for detecting the characteristics of the M line path based on the received signal. and a transmitting device in a single frequency communication system, comprising means for transmitting a signal by giving characteristics in advance to cancel distortion due to the characteristics of the radio propagation path, according to the characteristics of the radio propagation path detected by the above-mentioned means. It is.

[For production]

The present invention provides equalization I! on the radio base station side by the above means.
The aim is to resolve the above-mentioned problems by dividing the roles.

Specifically, the radio base station and the mobile station are provided with a device for detecting propagation path characteristics, assuming that the radio base station and the mobile station perform transmission and reception in a time-sharing manner using the same frequency. According to the detected propagation path characteristics, the wireless base station The equalizer performs equalization on the transmitted signal.

〔Example〕

The fIS1 diagram is a block diagram showing one embodiment of the present invention.

As shown in the figure, a radio base station side position 11, a receiving f & position 12, an antenna 13, a control device 14
, a propagation path characteristic detection B15, an antenna switching device 16, and an equal volume 17. The control device ra14 performs various controls such as transmission and reception timing commands, antenna switch control, and frequency settings used for transmission and reception.

The mobile station 2 also includes a transmitting device 21, a receiving device 22, an antenna 23, a control circuit 24, and an antenna switching device 25. Similarly to the control device 14, the control circuit 24 performs various controls such as transmission and reception timing commands, antenna switching control, and frequency settings used for transmission and reception.

In the figure, at the transmission timing of the mobile station, a carrier wave signal of frequency fc transmitted from the mobile station passes through the propagation path 3, is received by the seventh antenna 13, and then passes through the antenna switch 16 to the receiving device. Leads to 12. Receiving device 12
At t', necessary demodulation is performed, and the propagation path characteristic is detected by the propagation path characteristic detector 15, and isovolume tap coefficients are set based on this information.

The isovolume output is output to the reception output terminal 19.

Furthermore, at the transmission timing of the wireless base station, the baseband modulated signal is transmitted via the geometric volume 17, the transmitter 11, the antenna switch 16, and the antenna 13. The No. 13 signal received by the No. 7 antenna 23 is input to the receiving device 22 via the antenna switch 25. The reception terminal 22 performs necessary detection and demodulation, and outputs the result to the reception output terminal 27.

! ! Figure l's2 is a diagram showing an example of the frame structure and timing of transmission and reception signals of the above-mentioned radio base station and mobile station, in which 28 represents the 7-frame structure on the radio base station side, and 29 represents the 7-frame configuration on the mobile station side. There is.

In addition, INFB in the same figure is an information signal from the wireless base station to the mobile station, INFM is the information signal from the mobile station to the wireless plantation 1.6, and A is No. 13 for propagation path characteristic detection (training 4y
No.).

Transmission and reception between the S-line base station and the mobile station described above are performed according to the frame structure and timing shown in the figure.

In other words, the radio base station determines the propagation path characteristics (propagation delay characteristics).

As a detection method, for example, a correlation detection method similar to the conventional one can be used. Based on the detection result, the radio base station sets equal tap coefficients, equalizes the received signal corresponding to the propagation path characteristics, and obtains a good demodulated output.

This example shows a case where the training signal is placed in the first part of the frame, but it is often placed near the center of the frame in consideration of the movement of the large part.

In a wireless base station, when the characteristics of the propagation path are given by equation (2) above, the overall characteristics of the transmitting and receiving system are to achieve the propagation characteristics given by equation (3). It is important to remove the .

That is, by providing the characteristic given by equation (3) to the baseband modulated signal, the above condition can be satisfied without applying any processing to the received signal on the receiving side.

This shows that it is only necessary to apply modulation to the baseband No. 41 after passing through the above-mentioned container, and the $1
This can be realized by the MI shown in the figure.

FIG. 3 is a 1072 diagram showing another embodiment of the present invention.

According to this embodiment, good propagation quality can be ensured even when the propagation path characteristics change rapidly, which occurs when a mobile station moves at high speed.

In the ttS3 diagram, the wireless base station 1a is a transmitter 31
, receiving device! 32, antenna 33, control device 34, propagation path characteristic detector 35, antenna switching device 36, and flower vase 3
It has 7. The control device 34 performs various controls such as transmission/reception timing commands, antenna switch control, and frequency settings used for transmission and reception.

Furthermore, the mobile station 2a includes a transmitter 41, a receiver 42, an antenna 43, an equalizer 448, a control circuit 44, an antenna switch 45, and a propagation path characteristic detector=19. The control circuit 44 performs various controls such as vAH transmission/reception timing commands, antenna switching control, and frequency setting used for transmission/reception.

In the figure, a signal in the carrier band of frequency fc transmitted from the mobile station at the mobile station's transmission timing passes through the propagation path 3a, is received by the antenna 33, and is guided to the receiving device a32 via the antenna switch 36. It will be destroyed. The receiving device 3
In step 2, necessary demodulation is performed.In addition, the propagation path characteristics are detected by the propagation path characteristic detector 35, and the tap coefficients of the equal flower vase 37 are set based on the information. Furthermore, at the transmission timing of the wireless base station, the antenna switching unit 36 and the C/7 antenna 33 containing the equalizer information such as the tap coefficients are output to the receiving output terminal 39.
Sent via . At the mobile station, the antenna 43
The received signal is input to the receiving device 42 via the antenna switch 45 and detected. Receiving device 1
! The output of 42 passes through a flower vase 48 and then is output to a reception output terminal 47.

The control circuit 44 sends a command to the equalizer 48 to preset tap coefficients based on the equalizer information sent from the wireless base station. Further, more precise settings are made based on the main power of the propagation path characteristic detector 49.

As a result, the processing can be simplified compared to the case where the arithmetic processing for setting the tap coefficients is performed only by the mobile station.

Transmission and reception signals between the radio base station and the mobile station are carried out according to the frame v4 frequency and timing as shown in FIG. 2 as described above. In addition, when the transmission frequency of the wireless base station and mobile station is different, as is the case with car phones in Japan, the uplink propagation path characteristics of each frequency are different, so the training signal and the transmission frequency at the wireless base station are different. Even if the tap coefficients in North America are set to perform appropriate equalization on the received signal, and the baseband modulation signal is set in North America under the same conditions and equalized in advance, the mobile station Since the third option cannot eliminate the influence of propagation delay, good transmission quality cannot be ensured. This is the reason why the wireless 7.6 base station and mobile station use the same frequency, which is the premise of the present invention.

” - In order to facilitate understanding, one base station and one mobile station are explained in correspondence with each other. However, the present invention is not limited to this number; This can also be applied to cases such as propagation.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to completely omit or simplify the arithmetic processing when using a mobile station, etc., so that the circuit scale etc. can be reduced. This has the advantage of reducing power consumption and reducing power consumption.

[Brief explanation of drawings]

! FIG. 161 is a block diagram showing one embodiment of the present invention.
The figure shows an example of the frame structure and timing of transmitted and received signals, FIG. 3 is a block diagram showing another embodiment of the present invention, and FIG. 4 shows a radio base station and mobile station using conventional reception etc. FIG. 5 is a block diagram showing an example of the configuration, FIG. 5 is a diagram showing an example of the configuration of a transversal equalizer, and FIG. 6 is a diagram showing the configuration and detection principle of a propagation path characteristic detector using correlation detection. 1.1a... Wireless base station, 2.2a...
...Mobile station, 3.3a...Propagation path, 11. 21. 31. 41... Transmitting device, 12, 22, 32, 42...
...Receiving device, 13, 23 33, 4
3 ・・・・・・ Antenna, 14.34 ・・・
...control device, 1535, 49...
...Propagation path characteristic detector, IG, 25.36 45
・・・・・・ Antenna switch, 17, 37
．． 48 ... etc. North America, 18, 2G
, 38, 46......transmission input terminal,
19,27.39 47... Reception output terminal, 24 44... Control circuit, 28... Radio base station frame m r&, 29... Movement Station frame structure

Claims (1)

[Claims] In a radio device configured such that a transmitter and a receiver using the same frequency switch and use the same antenna, the radio device is provided with means for detecting the characteristics of a radio propagation path based on a received signal, Depending on the characteristics of the radio propagation path detected by the above means,
1. A transmitting device in a single frequency communication system, characterized in that the transmitter is provided with means for transmitting a signal with characteristics that cancel out distortion due to the characteristics of the radio propagation path.