JPH0620188B2 - Wireless repeater - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a case where a mobile station and a base station or mobile stations perform press talk wireless communication using radio waves of a single frequency. The present invention relates to a wireless relay device used for relaying communication.

[Conventional technology]

Among the wireless relay devices in the case of wireless communication using a radio wave of a single frequency, currently used devices or proposed devices include the following items.

The receiving unit and the transmitting unit of the wireless relay device are spatially completely separated, and the device is configured so that both parts do not interfere with each other (interference between transmission and reception) in the radio wave of the single frequency used, The one that operates the receiver and transmitter at the same time.

The receiver and transmitter of a wireless relay device are completely separated in time and operate alternately.

FIG. 6 shows the above apparatus and its wireless communication method. In the wireless communication in this case, communication in the direction of base station F → relay station C → mobile station M and communication in the direction of mobile station M → relay station C → base station F are alternately switched. Therefore, this device is also called a seesaw repeater.

More specifically, the wireless relay device of the relay station C includes two wireless relay devices of the same type, which are installed with ideal obstacles (hereinafter referred to as “mountains”) between which no mutual radio wave interference occurs. It is composed mainly of Ca and Cb. In the following, the constituent parts of the respective wireless repeaters will be represented separately by the subscripts a and b, but the respective constituent parts will be represented by the wireless repeaters Ca, Cb transmitters Ta and Tb, and receivers Ra and R.
b, antenna coupling portions ATa and ATb, antennas Aa and A
It consists of b.

Then, one receiving unit Rb (Ra) and the other transmitting unit Ta
(Tb) is always connected by the connecting part IF (generally connected in the intermediate frequency part).

To describe the wireless relay method, for example, when a radio wave of a frequency f emitted from the base station F is received by the reception unit Ra, the signal is transmitted from the transmission unit Tb to the mobile station M through the communication unit IF. That is, it is relayed (the above route is shown by a chain line).

In addition, relay is performed from the mobile station M to the base station F by the reverse route (indicated by a thin line) Rb → IF → Ta. (However,
When one of Rb → Ta and Ra → Tb is in operation, the other is inactive. ) This wireless relay method has the following problems.

(a) In order to prevent the device from oscillating due to the mutual interference between the radio repeaters Ca and Cb, an ideal mountain where a large attenuation of radio waves can be obtained is required between them, which makes it difficult to select the terrain. Sometimes it can not be installed.

(b) In order to prevent mutual interference between the radio repeaters Ca and Cb, in most cases, even if there are peaks, it is necessary to suppress the transmission output of Ta and Tb to be small. for that reason,
This method can only be used for relief of small dead zones and has no ubiquitous efficacy.

In the wireless communication in which the receiving unit and the transmitting unit are temporally separated and the two are alternately operated, as shown in FIG. 7, the wireless relay device C includes a transmitting unit T, a receiving unit R, and a transmission / reception switching control unit. CONT and voice delay unit (temporary storage unit) D are provided, and the voice received and demodulated by the reception unit R at the time of reception operation is temporarily stored in the voice delay unit D, and is transmitted by the transmission unit at the time of transmission operation. However, when the communication is performed by switching at high speed in the time division method, this has the following drawbacks.

That is, when switching is performed at high speed, the occupied bandwidth of radio waves is widened, which makes it impossible to apply the present wireless service. If the switching speed is reduced to such an extent that it can be applied, half of the voice information is lost due to the intermittent operation, and high-quality relay cannot be performed. Various methods have been devised to improve the missing voice information by compensating for it in the base station or mobile station, but there is a limit to the improvement, and in addition, there is a problem that existing equipment must be modified.

[Problems to be Solved by the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and provide an inexpensive wireless relay device that can relay high-quality communication with sufficient transmission output without difficulty in setting the geographical features to be installed.

[Means for Solving the Problems]

The present invention is a wireless relay device including two wireless relay devices arranged at a fixed distance, each of the wireless relay devices including a wireless reception unit, a wireless transmission unit, a storage unit, and A synchronization control unit for controlling them is provided, and the synchronization control units of both wireless repeaters are connected to each other by a synchronization line, and the wireless repeater transmission operation and the reception operation are respectively performed by the synchronization control unit. Are stored in the storage unit after temporarily storing the modulated signal which is controlled in such a manner as to be alternating within the wireless relay device and complementary to each other at the same time, and which is received and demodulated by the receiving unit. The present invention provides a wireless relay device characterized by being controlled to transmit by the transmitting unit.

In addition, the two wireless repeaters each have a directional antenna that suppresses radio wave interference between them, or the installation distance between the two wireless repeaters is 10 m or more.
Further, it has been found that good results are obtained when the repetition frequency of the alternating operation of the receiving operation and the transmitting operation is set to 10 to 50 Hz.

〔Example〕

Hereinafter, the present invention will be described with reference to a narrow band wireless relay device according to an embodiment.

FIG. 1 is a block diagram illustrating a configuration of a wireless relay device according to an embodiment of the present invention and a wireless relay method using the same.

The wireless relay device C is configured by combining two wireless relay devices Ca and Cb, which are arranged at a fixed distance of 10 meters or more, and each wireless relay device has a wireless reception unit T.
a and Tb, storage units MMa and MMb (these are temporary storages, and can be replaced by a delay circuit if a repetition frequency described later is determined), and a synchronization control unit CT that controls them.
a and CTb, and both synchronization control units CTa and CTb are connected to each other by a synchronization line Lab. (Similar to the above, the subscripts a and b distinguish between the two wireless repeaters).

The antenna couplers ATa and ATb are the same as those shown in FIG.

FIG. 2 is a time chart explaining the wireless relay method. As in the conventional case, this wireless relay device also has synchronization control units CTa and CTb, which are controlled by the wireless relay devices Ca and Cb so that the transmission operation and the reception operation are alternately performed. .

Then, referring to FIG. 1 and FIG. 2, for example, the radio wave of the frequency f emitted from the base station F is transmitted to the wireless relay Ca.
When it is received by the receiving unit Ra during the receiving operation of, the demodulated audio signal is temporarily stored in the storage unit MMa, and during the transmitting operation, the audio signal is taken out by the transmitting unit Ta and modulates the carrier wave of the same frequency f. Then, the radio wave fa (a1, a2, a) having the frequency f is intermittently transmitted via the antenna coupler ATa.
3, ...) and is transmitted from the antenna Aa to the mobile station M. That is, the relay is performed. (The above route is indicated by a dotted line.) The same thing is performed by the wireless repeater Cb, and when the radio wave of the frequency f emitted from the base station F is received by the receiving unit Rb,
The demodulated voice signal is temporarily stored in the storage unit MMb, and in time, the transmission unit Tb modulates the carrier wave of the frequency f, and the radio wave fb at which the frequency f is intermittently passed through the antenna coupler ATb.
(B1, b2, b3, ...) From the antenna Ab, this is also transmitted to the mobile station M and relayed.
(The path is indicated by a thin line.) The feature of this wireless relay device is that the synchronization control units CTa and CTb
However, in addition to controlling the wireless repeaters Ca and Cb as described above to alternately perform the transmitting operation and the receiving operation,
At the same time, the synchronization control units CTa and CTb are in communication with each other via the synchronization line Lab, and the wireless relays Ca and Cb are controlled so as to be complementary to each other (and thus to each other's receiving operation). Is what you are doing.

With this operation of the wireless relays Ca and Cb, the relay operation of the wireless relay device C that integrates both of them is as shown in FIG. 3, in which the radio wave of the frequency f emitted from the base station M is relayed by this wireless relay device C. , They are temporally complementary to each other,
Two intermittent radio waves fa (a1, a2, a3, ...
,), Fb (b1, b2, b3, ...) Are connected to the mobile station M in the form of continuous radio waves of frequency f that are connected together without a gap.

Since the transmission and reception operations of the two wireless repeaters Ca and Cb are temporally reciprocal, a feedback loop due to the wraparound of the same radio wave as in the case of the conventional two wireless repeaters of FIG. 6 cannot be performed, There is no worry about oscillation of the device. Therefore, a "mountain" or the like for attenuating the radio wave is not necessary between the two and can be installed anywhere.

However, it should be noted that when one of the two wireless repeaters is in the transmitting state, the other is in the receiving state, and therefore, when the other party's radio wave is strong, it is received. Therefore, the radio waves coming from the base station or mobile station are
The condition "stronger than the radio waves coming from the other side of the wireless repeater" is absolutely necessary.

Fortunately, however, the wireless relay device is generally installed on a high ground (for example, a height of 200 m. Hereinafter, likewise, parentheses will be used to give a numerical example), as shown in FIG. Base station (with output of 5 W, antenna height of 15 m) or mobile station (with output of 5 W, at a distance of 10 km each)
The electric field level from the antenna height 2 m) is usually sufficiently secured at least about 30 dBμ (60 dBμ and 40 dBμ).

On the other hand, the antenna height of each wireless repeater is a practical problem of about 2 m (and the output is 1 W = 143 dB).
μ), the distance between them is set to about 150 m even if there is no shielding on a plane ground, and a corner reflector CR is provided in the antenna element AE of each antenna Aa and Ab as shown in FIG. In order to have such a directivity, the strength of the radio wave from the other wireless repeater (-30 dB × 2 for antenna coupling loss, − for propagation loss
It can be easily reduced to 20 dBμ or less (15 dBμ) by 80 dB and antenna directivity of 6 dB × 2.

For this reason (assuming that the radio wave format used is FM)
Interference between wireless repeaters will in most cases not be a problem.

A slight separation between the two wireless repeaters Ca and Cb as described above produces a new effect.

Even if communication is impossible due to fading when there is only one wireless repeater, the present invention has a space diversity effect due to the existence of two isolated wireless repeaters, and communication can be secured. The higher the quality.

Next, if the switching is performed at high speed, the occupied bandwidth of the radio wave is widened to cause a problem, as described above, but in the case of the present invention, switching may be performed at low speed for one-way relay. This is because there is no continuous loss of voice in the entire wireless relay device even if the relay is intermittent in each wireless relay device.

Experiments have shown that the best call can be obtained when the repetition frequency of the alternating operation of reception and transmission is set in the range of 10 Hz or more and 50 Hz or less. If the repetition frequency is in this range, the occupied bandwidth of the radio wave will not be widened so much, and it can be sufficiently applied to the wireless service under the current regulations.

The synchronization control unit CTa of the two wireless repeaters Ca and Cb
As for the synchronization line Lab for communication between and CTb, it is sufficient to install a simple one using wire, low power wireless communication, optical communication, optical fiber or the like here, and since the distance is short, the cost required for installation is small.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, the conventional problem is solved and the cheap wireless relay apparatus which can relay a good quality communication with sufficient transmission output, without difficulty in selecting a topography even if installing is provided.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention, FIG. 1 is a block diagram showing the configuration of a wireless relay device of the present invention, FIG. 2 is a time chart of the wireless relay method, and FIG. FIG. 4 is a conceptual diagram of the relay method, FIG. 4 is a diagram showing an example of the electric field level, and FIG. 5 is a diagram showing the intensity of radio waves between the wireless relays. 6 and 7 are block diagrams showing the configuration of a conventional wireless relay device. C: wireless relay device, Ca, Cb; wireless relay device, Ra, Rb; wireless reception unit, Ta, Tb; wireless transmission unit, MMa, MMb; storage unit, CTa, CTb; synchronization control unit, Lab; synchronous line Aa , Ab; Antenna ATa, ATb; Antenna combiner

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koichi Ishikawa 2-5-5 Kimachi-dori, Aoba-ku, Sendai-shi, Miyagi (56) References JP-A-63-67832 (JP, A) JP-A-63- 299529 (JP, A)

Claims (4)

[Claims] 1. A wireless relay device comprising two wireless relay devices arranged at a fixed distance, each of the wireless relay devices being a wireless reception unit, a wireless transmission unit, a storage unit, And a synchronization control unit for controlling them, and the synchronization control units of both wireless repeaters are connected to each other by a synchronization line,
The radio repeater transmission operation and the reception operation are controlled by the synchronization control unit so as to be alternating within each radio repeater and complementary to each other at the same time, and received by the reception unit. Then, the modulated signal obtained by demodulation is
A wireless relay device, wherein the wireless relay device is controlled such that it is temporarily stored in the storage unit and then transmitted by the transmission unit. 2. The wireless relay apparatus according to claim 1, wherein the two wireless relay units each include a directional antenna for controlling radio wave interference between the two wireless relay units. 3. The wireless relay device according to claim 1, wherein an installation distance between the antennas of the two wireless relay devices is 10 m or more. 4. The radio relay apparatus according to claim 1, 2 or 3, wherein a repetition frequency of the alternating operation of the receiving operation and the transmitting operation is 10 to 50 Hz.