JPH04134934A - Mobile communication system - Google Patents

Abstract

PURPOSE:To prevent insertion of an erroneous delay by stopping tentatively the revision of a delay insertion station due to a fault of a phase difference measuring station in the mobile communication system having a peripheral station requiring phase synchronization. CONSTITUTION:A phase difference measuring station 3 encodes alarm information of the phase difference station 3 and a delay measured based on a 1st special signal (such as a synchronizing signal) at a prescribed interval included in a signal sent from a delay insertion station 4 in a prescribed timing and sends back the result to the delay insertion station 4. The delay insertion station 4 decodes the alarm information from the signal to be sent and a measured delay and keeps the delay inserted to a variable delay section as delay information sent precedingly when the phase difference measuring station 3 is in the alarm state (e.g. RF receiver alarm or the like) and inhibits the insertion of the delay decoded newly. Thus, the insertion of an erroneous delay is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to phase synchronization means necessary for simultaneous multi-station transmission in a mobile communication system.

〔overview〕

The present invention prevents incorrect delay amount insertion in a mobile communication system that has peripheral stations that require phase synchronization by temporarily stopping the update operation of a delay amount insertion station due to a failure of a phase difference measurement station. It was made so that it could be done.

[Conventional technology]

In mobile communication systems, when multiple small wireless zones are used to cover a wide service area, the same transmission radio waves are sent out simultaneously from multiple wireless base stations installed in each small wireless zone for effective use of frequencies. Many methods are used (Section 7.4 of “Fundamentals of Mobile Communications” published by the Institute of Electronics, Information and Communication Engineers)
. At this time, in order to ensure the necessary transmission quality in areas where the strength of radio waves from a plurality of radio base stations is approximately equal, it is necessary to synchronize the phases of the signals transmitted from each radio base station.

In order to achieve phase synchronization between two base stations, the delay time of the transmission path between the station that sends the signal (hereinafter referred to as the central station) and each wireless base station is measured, and the delay time is determined when all wireless base stations It is necessary to delay the signal to the station so that it is the same as the central station.

One way to measure delay time is to use a wireless line, such as by receiving and comparing radio waves from a reference wireless base station (hereinafter referred to as the reference station) at other wireless base stations (hereinafter referred to as peripheral stations). It is common (section 7.5 of "Car Telephone" published by the Institute of Electronics, Information and Communication Engineers).

Note that it is necessary to insert a delay circuit between the central station and the reference station so that the delay time between the central station and the reference station is greater than the delay time of the transmission path between the central station and other peripheral stations. .

FIG. 8 shows the system system, and FIG. 9 shows the equipment system of peripheral stations. In the peripheral station 29, the RF receiver 19 receives radio waves from the own station and the reference station from the receiving antenna 8, demodulates each radio wave, and converts the second special signal included in the signals from the two base stations as shown in FIG. 34 phase differences are compared, and the delay time difference (
By measuring the phase amount) 35, the delay time of the transmission path can be equivalently measured.

At this time, since the frequency of the radio waves to be received is the same, as shown in FIG. 10, when receiving the reference station radio wave 31, it is necessary to temporarily stop the own peripheral station radio wave 32 and receive it. However, if the distance between the reference station 2 and the peripheral station 29 is long, or if there is an obstacle such as a mountain 11 between the reference station 2 and the peripheral station 29 as shown in Fig. The RF receiver 19 may not be able to obtain a sufficient received electric field. In such cases, the gain has been increased by using a high-gain receiving antenna 8 or by inserting an amplifier with a good NF in the front stage of the RF receiver 19. In addition, as shown in FIG. 1 and FIGS. 5 to 7, the delay time difference (phase amount) of the transmission path between two base stations (between the reference station 2 and the peripheral station 29)
The phase difference measurement station is divided into a station that measures the delay time difference (hereinafter referred to as the phase difference measurement station) and a peripheral station that inserts the measured delay time difference (phase amount) (hereinafter referred to as the delay amount insertion station). By installing it at a point (for example, an intermediate point) where the received electric field from the reference station 2 and the received electric field from the delay amount insertion station are sufficiently obtained, the transmission path between the two base stations (the reference station 2 and the delay amount insertion station) can be improved. Delay time (phase amount) can be measured.

In addition, the phase difference measured at the phase difference measuring station is encoded,
Furthermore, the signal sent from the central station to the delay amount insertion station is branched and sent back to the delay amount insertion station along with the signal sent to the phase difference measurement station using a transmission path. The delay amount insertion station decodes the transmitted encoded delay amount, inserts the delay amount into the variable delay 818, corrects the phase difference, and synchronizes the phases between the two base stations.

[Problem to be solved by the invention]

When performing phase synchronization by dividing the conventional phase difference measurement station and delay amount insertion station, a failure (for example, an RF receiver alarm, etc.) may occur at the phase difference measurement station, resulting in incorrect delay amount information. When sent from the phase difference measuring station to the delay insertion station,
The delay insertion station decodes the encoded delay amount from the signal sent from the phase difference measurement station and inserts the incorrect delay amount into the variable delay unit by decoding the transmitted signal from the reference station and the delay insertion station. This had the disadvantage that phase synchronization could not be obtained.

The present invention aims to eliminate such drawbacks and to provide a mobile communication system that can prevent insertion of erroneous delay amounts.

[Means to solve the problem]

The present invention relates to a plurality of peripheral stations connected to a central station via transmission paths with transmission delays, a reference station that is one of the peripheral stations and has a reference phase that serves as a reference for the synchronization phase of each peripheral station, and A means for measuring the phase difference between the synchronization phase of the other peripheral station and the reference phase, and generating a delay amount signal indicating this phase difference, which is installed at a position where it can receive radio waves from another peripheral station. In a mobile communication system, the other one of the peripheral stations has a delay means for matching the synchronization phase of the own station with the reference phase based on the delay amount signal arriving from the phase difference measurement station. , the above phase difference measurement station is
Means is provided for adding a failure signal indicating a failure of the own station to the delay amount signal, and when the other one of the peripheral stations detects this failure signal, the phase of the delay means is corrected by the delay amount signal accompanying this failure signal. It is characterized by having a means for temporarily prohibiting it. Here, the delay amount signal to which the fault signal is added may be periodically generated.

[Effect]

At the phase difference measuring station, the amount of delay measured based on the first special signal (for example, a synchronization signal) at a certain interval included in the signal sent from the delay amount insertion station and the alarm information of the phase difference measuring station are kept constant. It is encoded at the timing of and sent back to the delay amount insertion station. The delay amount insertion station decodes the alarm information and the measured delay amount from the sent signal, and if the phase difference measurement station has an alarm (for example, an RF receiver alarm, etc.), it decodes the amount of delay to be inserted into the variable delay section. The previously sent delay amount information is retained, and insertion of a newly decoded delay amount is prohibited.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a system diagram, Figure 2 is a system diagram of the delay amount insertion station in Figure 1, Figure 3 is a system diagram of the phase difference measurement station in Figure 1, and Figure 4 is the delay from the phase difference measurement station. The signal to the delay amount insertion station and the signal from the delay amount insertion station to the phase difference measurement station are shown.

As shown in FIGS. 1 to 3, this embodiment includes a plurality of peripheral stations connected to a central station 1 by a transmission path 10 with transmission delays, and one of the peripheral stations. The synchronization phase of the delay insertion station 4, which is the other peripheral station, is installed at a position where it can receive radio waves from the reference station 2, which has a reference phase that serves as the reference for the synchronization phase of the other peripheral station. The station 3 includes a phase difference measurement station 3 having a phase comparison section 20 and an encoding section 23, which are means for measuring the phase difference between the reference phase and the reference phase, and generating a delay amount signal indicating this phase difference. One is the delay amount code decoding section 17 and the variable delay section 1, which are delay means for matching the synchronization phase of the local station with the base phase based on the delay amount signal arriving from the phase difference measurement station 3.
Further, as a feature of the present invention, the phase difference measurement station 3 is provided with means for adding a failure signal indicating a failure of the own station to the delay amount signal, and the other one of the peripheral stations is:
An alarm code decoder 16 is provided which is a means for temporarily prohibiting phase correction of the delay means by a delay amount signal accompanying this fault signal when the fault signal is detected. Here, the means for generating the delay amount signal indicating the phase difference periodically generates the delay amount signal to which the fault signal is added.

Next, the operation of this embodiment will be explained.

In Fig. 1, if there is a mountain 11 or the like that interferes with radio waves between the reference station 2 and the delay insertion station 4, the delay insertion station 4 will not be able to receive the reference station radio wave 12, making phase synchronization impossible. . Therefore, the phase difference measurement station 3 is installed at a location where both the reference station radio wave 12 and the delay amount insertion station radio wave 13 can be received.

At the phase difference measuring station 3, the received signal is demodulated by the RF receiver 19, and the phase difference of the second special signal 340 included in the signals from the reference station 2 and the delay amount insertion station 4 is detected by the phase comparator as shown in FIG. 20, and a delay time difference (phase difference) 35 is measured. The measured phase difference 35 is transmitted to the encoder 2 at the same time as the alarm information 26 of the phase difference measurement station 3 such as the RF receiver alarm 22 based on the first special signal at regular intervals as shown in FIG.
3, the signal sent from the central station 1 to the delay amount insertion station 4 via the transmission line 10 is branched, and is added to the first signal 27 sent to the phase difference measurement station 3 and delayed. The data is sent back to the quantity insertion station 4.

On the other hand, in the delay amount insertion station 4, the delay amount is detected from the second signal 28 carrying the encoded delay amount 25 sent via the transmission path 0, and the delay amount code decoder 17 also measures the phase difference. The alarm information of the station 3 is decoded by the alarm code decoder 16,
If there is alarm information 26 such as the RF receiver alarm 22, it is prohibited to insert a delay amount into the variable delay section 1B, and if there is no alarm information, the delay amount is inserted into the variable delay section 18 and the phase By correcting the reference station 2
The phases of the signal from the delay amount insertion station 4 and the signal from the delay amount insertion station 4 are synchronized.

〔Effect of the invention〕

As explained above, the present invention transmits a signal sent from a phase difference measurement station to a delay amount insertion station with encoded measurement delay amount and encoded alarm information of the phase difference measurement station at the same time. On the other hand, the delay amount insertion station decodes the alarm information and the measured delay amount from the sent signal, and if the phase difference measurement station has an alarm (for example, an RF receiver alarm), the delay amount is inserted into the variable delay section. By retaining the previously sent delay amount information and prohibiting insertion of a new delay amount, it is possible to prevent insertion of an incorrect delay amount.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention. FIG. 2 is a block diagram of the delay amount insertion station in FIG. 1. FIG. 3 is a configuration diagram of the phase difference measuring station shown in FIG. 1. FIG. 4 is a configuration diagram of an encoded signal sent from a phase difference measurement station to a delay amount insertion station. FIG. 5 is a configuration diagram of a conventional delay amount insertion station. FIG. 6 is a configuration diagram of a conventional phase difference measuring station. FIG. 7 is a configuration diagram of a coded signal sent from a conventional phase difference measurement station to a delay amount insertion station. FIG. 8 is an overall configuration diagram of a conventional example. FIG. 9 is a configuration diagram of the peripheral station in FIG. 8. FIG. 10 is a measurement diagram of phase difference. FIG. 11 is a conventional overall configuration diagram with obstacles such as mountains. DESCRIPTION OF SYMBOLS 1... Central station, 2... Reference station, 3... Phase difference measurement station, 4... Delay amount insertion station, 5... Transmission antenna, 6
...Modulator/demodulator (MD), 7.8.9...Central station receiving antenna, 10...Transmission line, 11...Mountain, 12.
31...Reference station radio wave, 13...Delay amount insertion station radio wave,
14...Central station radio wave, 15...Transmitter, 16...
Alarm code decoding unit, 17... Delay amount code decoding unit, 1
8... Variable delay unit, 19... RF receiver, 20...
- Phase comparison section, 21... Code decoding section, 22... RF
Receiver alarm, 23... Encoding unit, 24... First special signal, 25... Encoded delay amount, 26...
Encoded alarm information, 27...first signal, 28
...Second signal, 29...Peripheral station, 30.32...
Local station radio wave, 33... Stop period, 34... Second special signal, 35... Phase difference. Actual example: nIP Bunkakai ￥52 Figure Actual example of Fukuzuki Jing style conventional da'' 0 Shunbu configuration Kairyo 5 Figure conventional flight] Part of the previous example of April shadow style 3b Irn , 14 'JJ' = Traditional month 10 figure

Claims (1)

[Scope of Claims] 1. A plurality of peripheral stations connected to the central station via transmission lines with transmission delays, and one of the peripheral stations having a reference phase that serves as a reference for the synchronization phase of each peripheral station. A delay amount signal that is installed at a position where it can receive radio waves from the reference station and another one of the above-mentioned peripheral stations, measures the phase difference between the synchronization phase of this other peripheral station and the reference phase, and indicates this phase difference. The other one of the peripheral stations has delay means for matching the synchronization phase of its own station with the reference phase based on the delay amount signal arriving from the phase difference measurement station. In the mobile communication system, the phase difference measuring station is equipped with means for adding a fault signal indicating a fault in its own station to the delay amount signal, and the other one of the peripheral stations adds a fault signal to the delay signal when detecting the fault signal. A mobile communication system characterized by comprising means for temporarily inhibiting phase correction of the delay means by an accompanying delay amount signal. 2. The mobile communication system according to claim 1, wherein a delay amount signal to which a failure signal is added is periodically generated.