JPH08307932A - Tdm synchronizing method/system among mobile communication base stations - Google Patents

Abstract

PURPOSE: To provide TDM synchronizing method/system among mobile communication base stations, which can solve the problem that call synchronizing signals transmitted from peripheral base stations cannot instantaneously be synchronized. CONSTITUTION: The TDM synchronizing method/system among the mobile communication base stations are provided which receive and store the call signals by a phase delay correction part 11 in the respective peripheral base stations 2 when a central base station 1 simultaneously transmits the call signals to the plural peripheral base stations 2, generate GPSCLK of a one second period by a GPS reception part 13 based on GPS time transmitted from a GPS satellite 20, output a value (phase delay information) obtained by counting time till GPSCLK from the call signal to the phase delay correction part 11 by a phase delay detection part 12, read the call signal with delay by changing a read address from a storage part 11a only by an amt. of address based on phase delay information by the phase delay correction part 11 and as a result, transmit the call signal at the timing of next GPSCLK.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a TDM synchronization method between mobile communication base stations, and in particular, it is used for correction of phase delay between transmission signals from mobile communication base stations, and a GPS time in which a plurality of base stations are set. The present invention relates to a TDM synchronization method between mobile communication base stations and a TDM synchronization system between mobile communication base stations that can perform simultaneous synchronous transmission based on the above.

[0002]

2. Description of the Related Art A conventional mobile communication base station TDM synchronization method will be described with reference to FIGS. FIG. 4 is a schematic configuration diagram of a conventional TDM synchronization system between mobile communication base stations, and FIG. 5 is a timing chart diagram showing a conventional TDM synchronization method between mobile communication base stations.

A TDM (Time Division Multiplex:
Time division multiplexing) communication is a communication method in which, when one transmission path is shared by a number of channels, pulse signals shifted in time by the number of channels are arranged and transmitted. The modulation methods include pulse amplitude modulation (PAM) and pulse width modulation (PW).
N), pulse position modulation (PPM), pulse number modulation (PN
M), pulse code modulation (PCM), etc.

First, a schematic configuration of a conventional TDM synchronization system between mobile communication base stations will be described with reference to FIG. As shown in FIG. 4, the conventional TDM synchronization system between mobile communication base stations is basically composed of a central base station 1 ', peripheral base stations 2', and a receiver 5, and is called a central base station 1 '. Each of the plurality of peripheral base stations 2'is connected by a line (B signal relay line).

The central base station 1'is connected to the network, receives a call signal from the network, and simultaneously transmits the call signal to a plurality of peripheral base stations 2'via B signal relay lines. . The peripheral base station 2'is provided for each area, and in the example of FIG. 4, three peripheral base stations 2'-1,
2'-2 and 2'-3 are provided.

The internal configuration of the peripheral base station 2'will be further described. The peripheral base station 2'includes a phase correction unit 6, a transmission unit 7, a phase correction antenna 3, and a peripheral base station antenna 4. It is configured.

Here, the peripheral base station antenna 4 is an antenna for transmitting a calling signal to the receiver 5, and the transmitting unit 7 transmits a calling signal using the peripheral base station antenna 4. Is.

Further, in the phase corrector 6, if a carrier line is used as the B signal relay line, a delay occurs at the time when the paging signal arrives at the peripheral base station 2'due to the distance or the like, and each peripheral base station 2'is delayed. Since the arrival times are different and the timings for transmitting the calling signals do not match, each peripheral base station 2 '
This is for performing a correction for synchronizing the transmission timing in. The phase correction antenna 3 is an antenna used for the above correction. The operation of the phase corrector 6 will be described later with reference to FIG.

The receiver 5 receives the ringing signal transmitted from the peripheral base station 2 ', determines whether or not the signal is addressed to itself, and if the signal is addressed to itself, acquires the signal contents,
The alarm sound is generated and displayed.

Next, a conventional TDM synchronization method between mobile communication base stations will be described with reference to FIG. First, when a calling signal is transmitted from the network to the central base station 1, the central base station 1 sends the calling signal to the peripheral base stations 2'-1, 2'-2, 2'-3 via the B signal relay line. To transmit. Then, the peripheral base station 2'corrects the delay time when compared with the phase of another peripheral base station 2'which should be the reference phase.

Peripheral base station 2 '(especially peripheral base station 2'-
To specifically explain the correction of the delay time in 2), the peripheral base station 2'-2 receives the ringing signal transmitted from the peripheral base station antenna 4 of its own station by the phase correction antenna 3 of its own station, Next, the call signal from the peripheral base station 2'-1 which should be the reference phase is received, and the phase delay Δt1 of both is detected from the synchronization code included in both call signals (see FIG. 5 (a)). .

Then, the phase correction unit 6 of the peripheral base station 2'-2.
Then, Δt1 is the time for one slot in TDM Δt0
Then, the transmission timing is adjusted so that, and one dummy slot is added to the calling signal (see FIG. 5B). Then, from the transmission of the next call signal, the peripheral base station 2 '
-1 can be synchronized with the peripheral base station 2'-2.

Further, with reference to the corrected phase of the peripheral base station 2'-2, the phase difference Δ with the ringing signal of the peripheral base station 2'-3 is set.
Similarly, t2 (see FIG. 5 (c)) is corrected to establish the synchronized state. If the number of peripheral base stations 2'is increased, the phase of the calling signal between the peripheral base stations is similarly corrected.

Such a conventional TDM between mobile communication base stations
For the synchronization method, see NEC Res. & Develop., No. 8
4 January, 1987, T. Kuki et al "High Capaci
tyRadio Paging System ”.

[0015]

However, in the conventional TDM synchronization method between mobile communication base stations, the delay time is corrected so that one of the other peripheral base stations establish synchronization with the reference peripheral base station. However, because of the sequential transmission synchronization method in which the delay time is sequentially corrected on a one-to-one basis such that one station of another peripheral base station establishes synchronization with the corrected peripheral base station as a reference, There is a problem that a complicated process is required until the synchronization is finally established and the delay correction completion time increases in proportion to the number of peripheral base stations.

The present invention has been made in view of the above-mentioned circumstances, and a TDM synchronization method between mobile communication base stations and a mobile communication base station capable of instantaneously establishing synchronization of a calling signal transmitted from each peripheral base station. An object is to provide an inter-TDM synchronization system.

[0017]

According to a first aspect of the present invention for solving the above-mentioned problems of the conventional example, in a TDM synchronization method between mobile communication base stations, a call signal and a GPS satellite are used in each peripheral base station. The GPS time is received using satellite communication, the GSP clock is generated based on the GPS time, the delay time of the calling signal is detected based on the generated GPS clock, and the cycle time of the GPS clock is detected. It is characterized in that the phase delay of the ringing signal is corrected based on the number of counts of the time obtained by subtracting the delay time, and the ringing signal is transmitted toward the receiver after correction, and the central base station and each peripheral base station. Even if various delay times occur when the call signal is transmitted to the station, each peripheral base station is synchronized with the cycle of the GPS clock generated from the GPS time received from the GPS satellite. There because it transmits the call signal simultaneously, it is possible to establish synchronization of the paging signal instantaneously.

The invention according to claim 2 for solving the above-mentioned problems of the prior art is, in a TDM synchronization system between mobile communication base stations, a central base station for transmitting a paging signal, and a central base station for transmitting a paging signal. The call signal is received via a trunk line, GPS time is received from the GPS satellite using satellite communication, a GPS clock is generated based on the GPS time, and the call signal is received based on the GPS clock. Of the delay time is detected, the phase delay of the ringing signal is corrected based on the count number of the time obtained by subtracting the delay time from the cycle time of the GPS clock, and the ringing signal is transmitted toward the receiver after correction. It is characterized by having a plurality of peripheral base stations that operate, even if various delay times occur when a call signal is transmitted from the central base station to each peripheral base station, the GPS For each peripheral base stations in synchronization with the cycle of the GPS clock generated by the GPS time received from the star can send a call signal simultaneously, it is possible to establish synchronization of the paging signal instantaneously.

The invention according to claim 3 for solving the problem of the above-mentioned conventional example is the T between mobile communication base stations according to claim 2.
In the DM synchronization system, a peripheral base station receives a GPS time transmitted from a GPS satellite using satellite communication, and a GPS receiving unit that generates a GPS clock based on the GPS time, and a central base station. A first detection unit that detects a unique word of a calling signal and outputs a unique word detection signal, and detects a delay time of the calling signal based on the GPS clock from the GPS clock and the unique word detection signal, Further, a second detector for outputting a count number for the time obtained by subtracting the delay time from the cycle time of the GPS clock as phase delay information, and temporarily storing the ringing signal received from the central base station, A delay correction unit that corrects and outputs the phase delay of the temporarily stored ringing signal based on information, and a delay correction unit that outputs the delay signal. It is characterized by having a transmitting unit for transmitting the ringing signal directed to the receiver, even if the delay time of various when the ringing signal is transmitted from the central base station to each peripheral base station, Since the peripheral base stations can transmit the calling signal all at once in synchronization with the cycle of the GPS clock generated from the GPS time received from the GPS satellite, the synchronization of the calling signal can be instantly established.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. Mobile communication base station TDM synchronization method and mobile communication base station T according to an embodiment of the present invention
The DM synchronization system uses GPS (G
lobal Positioning System) Generates a GPS clock from GPS time received from satellite using satellite communication, further generates a PLL clock from the GPS clock, and the time from the received call signal to the GPS clock is PLLCL.
Counting with K and delaying the transmission of the calling signal based on the count number, each peripheral base station can send the calling signal to the receiver all at once in synchronization with the cycle of the GPS clock,
All peripheral base stations can simultaneously correct the various delay times that occur from the central base station to each peripheral base station, and instantly establish the synchronization of the calling signal.

First, the inter-mobile communication base station T of this embodiment
The configuration of the DM synchronization system will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a TDM synchronization system between mobile communication base stations according to an embodiment of the present invention. It should be noted that portions having the same configuration as in FIG.

The TDM synchronization system between mobile communication base stations of this embodiment is basically the same as the conventional one, and the central base station 1
And a plurality of peripheral base stations 2 and a receiver 5, and the information transmitted from the GPS satellite 20 is used as a feature of this embodiment. However, the transmission control method of the paging signal in the central base station 1 of the present embodiment is different from that of the conventional central base station 1 ', and the central base station 1 of the present embodiment is further provided with a GPS antenna 14. This is different from the conventional central base station 1 '. Further, instead of the conventional phase correction unit 6 and phase correction antenna 3 inside the peripheral base station 2, the synchronization circuit unit 10 and the GPS antenna 1 are provided.
4 is provided, which is different from the conventional peripheral base station 2 '.

Next, the T between mobile communication base stations of the present embodiment
Each part of the DM synchronization system will be specifically described.
A description of the same components as the conventional one will be omitted, and only the characteristic portions of the present embodiment will be described. GPS satellite 20
Is an orbiting satellite used in a satellite navigation system developed by the US Department of Defense for military purposes.It has an extremely accurate atomic clock inside and constantly sends out periodic continuous signals based on a fixed time. This periodic signal is referred to as a GPS time signal here (see "Mobile Communications", Masaaki Shinji, Maruzen Co., Ltd., September 1989, p264).

The GPS antenna 14 is an antenna for receiving a signal (GPS time signal) periodically sent from the GPS satellite 20.

The central base station 1 transmits a paging signal to the receiver 5 received from the network to the plurality of peripheral base stations 2 via the B signal relay line as in the conventional case. The feature of the central base station 1 is that the GPS time signal transmitted from the GPS satellite 20 is used for the GPS antenna 1
4 and receives a periodic pulse having a period of 1 second based on the GPS time signal (hereinafter referred to as “GPS clock” or “GPSC”).
(Referred to as “LK”), and a call signal is transmitted to the peripheral base station 2 at the timing of the generated GPSCLK.

The peripheral base station 2 receives the ringing signal transmitted from the central base station 1 via the B signal relay line in the synchronizing circuit section 10 and generates a GPS based on the GPS time transmitted from the GPS satellite 20. The calling signal is transmitted via the transmission unit 7 in synchronization with the clock.

Here, the internal configuration of the synchronization circuit section 10 of the peripheral base station 2 of the present embodiment will be specifically described with reference to FIG. FIG. 2 is a block diagram showing the configuration inside and around the synchronization circuit unit 10 of the peripheral base station 2 according to the present embodiment. As shown in FIG. 2, the inside of the synchronization circuit unit 10 of the peripheral base station 2 according to the present embodiment includes a phase delay correction unit 11, a phase delay detection unit 12, a GPS reception unit 13, a PLL 15, and
The UW detector 16 and the GPS receiver 13
The PS antenna 14 is connected.

Each part inside the synchronous circuit section 10 will be specifically described. The GPS receiver 13 includes a GPS antenna 14
Based on the GPS time signal received via the GPS, a 1-second periodic pulse (hereinafter referred to as "GPS clock" or "GPSC").
(Referred to as “LK”) and is supplied to the PLL 15 and the phase delay detection unit 12 described later. In addition, this GPS
Since the CLK is generated based on the common GPS time signal in the central base station 1 and each peripheral base station 2, it can be considered that all the GPS CLKs generated in each base station are synchronized.

The PLL 15 is a PLL (Phase-Locked Loo).
The main purpose is to generate a clock for counting the delay time of receiving the paging signal in each peripheral base station 2 in the p) type signal oscillator. Specifically, PLL15
Is the GPS supplied from the GPS receiver 13 and having a cycle of 1 second.
CLK is input and a clock of 1 / n second cycle (hereinafter,
A "PLL clock" or "PLLCLK") is generated and supplied to the phase delay detection unit 12. Here, n is a value determined by the accuracy of phase delay correction.
Regarding the PLL method, "High frequency measurement" Hiroshi Yamamoto,
Sumio Okawa Co-Corona Publishing Co., September 1991
p232-p233.

The UW detector 16 detects a unique word (hereinafter "U" included in the call signal transmitted from the central base station 1).
W)). Specifically, when the UW in the ringing signal transmitted from the central base station 1 and obtained via the phase delay correction unit 11 is detected, the phase delay detection unit 1
2 outputs a UW detection signal. Here, UW contains a synchronization code (synchronization signal).

The phase delay detector 12 receives the ringing signal transmitted by the central base station 1 and received by the peripheral base stations 2, and the GP signal.
It detects the phase difference from SCLK and measures the timing of transmitting the calling signal. Specifically, the GPS receiver 1
If the phase difference between the GPSCLK supplied from No. 3 and the UW detection signal received from the UW detection unit 16 is Δt, (G
The time from the UW detection signal to the next GPSCLK, which is the period of the PSCLK cycle−Δt), is actually counted by a counter or the like using the PLLCLK supplied from the PLL 15, and the count value is used as phase delay information in the phase delay correction unit. It is designed to output to 11. In this embodiment, the GPSCLK cycle is 1 second.

The phase delay correction unit 11 has therein a storage unit 1 for temporarily storing a ringing signal transmitted from the central base station 1.
1a and performs phase delay correction based on the phase delay information output from the phase delay detection unit 12, resulting in GP
The calling signal is output to the transmission unit 7 at a timing synchronized with SCLK.

Specifically, when the phase delay correction unit 11 receives a calling signal via the B signal relay line, it temporarily stores the received calling signal in the storage unit 11a. Further, the ringing signal input to and stored in the phase delay correction unit 11 is output to the UW detection unit 16 for UW detection. Then, based on the phase delay information of the (1-Δt) second counted value received from the phase delay detection unit 12, the calling signal stored in the storage unit 11a is changed by the address corresponding to the phase delay information. The address is read from the address, output to the transmission unit 7, and transmitted.

By performing the above-described phase delay correction in each peripheral base station 2, the GPSCLK from each peripheral base station 2 is corrected.
Call signals are transmitted all at once at a timing synchronized with.

Next, the T between mobile communication base stations of the present embodiment
The outline of the operation of the DM synchronization system will be described with reference to FIGS. TD between mobile communication base stations according to the present embodiment
In the M synchronization system, the central base station 1 uses the GPS satellites 2
GPSC signal from 0
When the LK is generated and a call signal for calling the receiver 5 is received from the network, the call signal is transmitted to all the peripheral base stations 2 at a timing synchronized with GPSCLK.

Then, in each peripheral base station 2, when the phase delay correction unit 11 of the synchronization circuit unit 10 receives the ringing signal transmitted from the central base station 1, it temporarily stores it in the storage unit 11a,
Immediately read out and output to the UW detection unit 16. Then, when the UW detection unit 16 detects the UW in the ringing signal received from the phase delay correction unit 11, it outputs the UW detection signal to the phase delay detection unit 12.

On the other hand, in the peripheral base station 2, the GPS time signal periodically sent from the GPS satellite 20 is used to synchronize the GPS time signal.
Is received by the GPS antenna 14 of the
Generate GPSCLK of 1 second cycle based on PS time,
It is supplied to the phase delay detector 12 and the PLL 15. Then, in the PLL 15, based on the GPSCLK supplied from the GPS receiving unit 13, the PLLCLK having a cycle of 1 / n second
Is generated and supplied to the phase delay detector 12.

Then, the phase delay detector 12 detects the UW detection signal received from the UW detector 16 from the GPS receiver 13
The time (1−Δt) seconds from the GPSCLK to the GPSCLK supplied thereto is counted using the PLLCLK supplied from the PLL 15, and the count value is output to the phase delay correction unit 11 as the phase delay information.

When the phase delay correction unit 11 receives the phase delay information from the phase delay detection unit 12, the phase delay correction unit 11 changes the read address of the storage unit 11a based on the phase delay information, and the data stored in the storage unit 11a from the read address. Is read out and output to the transmission unit 7, and the transmission unit 7 transmits a calling signal from the peripheral base station antenna 4 to the receiver 5.

By the above operation, each peripheral base station 2
The manner in which the calling signal transmitted from the device is transmitted in synchronization with GPSCLK will be specifically described with reference to FIG. FIG. 3 is a timing chart showing the TDM synchronization method between mobile communication base stations according to the present embodiment.

In the TDM synchronization system between mobile communication base stations of the present embodiment, the GPSCLK shown in FIG. 3A is calculated based on the GPS time received from the GPS satellite 20 in the central base station 1 and each peripheral base station 2. Is generating. Further, in the peripheral base station 2, the GPS is further used by the PLL 15.
PL of 1 / n second cycle shown in FIG. 3 (b) based on CLK
Generating LCLK.

When the central base station 1 receives a calling signal from the network, as shown in FIG.
A call signal is transmitted to each peripheral base station 2 at the timing of GPSCLK (A).

Then, in the peripheral base station 2-1, FIG.
As shown in (3), by receiving the ringing signal after the phase delay time Δt3 and performing the phase delay correction, (1-Δt3)
A call signal is transmitted at the timing of GPSCLK (B) after a second. After that, when the call signal is received, the call signal is transmitted with the first GPSCLK after the reception (FIG. 3).
(E)).

Similarly, in the peripheral base station 2-2, FIG.
As shown in, by receiving the ringing signal after the phase delay time Δt4 and performing the phase delay correction, (1-Δt4)
A call signal is transmitted at the timing of GPSCLK (B) after a second. After that, when the call signal is received, the call signal is transmitted with the first GPSCLK after the reception (FIG. 3).
(G)).

As a result, in the plurality of peripheral base stations 2, the ringing signal transmitted from the central base station 1 at the timing of GPSCLK (A) and the ringing signal at the timing synchronized with GPSCLK (B) are simultaneously received by the receivers. 5 is transmitted, and thereafter, the ringing signals are simultaneously transmitted to the receiver 5 at the timing synchronized with GPSCLK.

According to the TDM synchronization method between mobile communication base stations and the TDM synchronization system between mobile communication base stations according to the present embodiment, each peripheral base station 2 that receives the paging signal transmitted from the central base station 1 receives it. The time from the signal to GPSCLK is counted by PLLCLK, and the read address from the storage unit 11a is changed based on the counted number to delay the transmission of the calling signal and transmit the signal at the GPSCLK timing. GPS at peripheral base station 2
Since the call signals are transmitted all at once in synchronization with CLK, there is an effect that synchronization can be achieved in a short time.

Further, the T between mobile communication base stations of this embodiment is
In the DM synchronization system, since GPS time that can be recognized as a common time by each device is used as a time for synchronization, there is an effect that highly accurate synchronization can be realized.

[0048]

According to the invention described in claims 1, 2 and 3,
Each peripheral base station generates a GPS clock from the GPS time received from the GPS satellite using satellite communication,
Using the PS clock as a reference, the delay time of the ringing signal received from the central base station is detected, and the ringing signal corrected for phase delay is calculated based on the count number of the time obtained by subtracting the delay time from the cycle time of the GPS clock. Mobile communication base station TDM synchronization method for transmitting to receiver and mobile communication base station TD
Since the M synchronization system is used, even if there are various delay times when the call signal is transmitted from the central base station to each peripheral base station, it is synchronized with the cycle of the GPS clock generated from the GPS time received from the GPS satellite. Then, since the peripheral base stations can simultaneously transmit the calling signal, there is an effect that the synchronization of the calling signal can be instantly established.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an inter-mobile communication base station T according to an embodiment of the present invention.
It is a schematic block diagram of a DM synchronization system.

FIG. 2 is a block diagram showing a configuration inside and around a synchronization circuit unit of a peripheral base station according to the present embodiment.

FIG. 3 is a timing chart diagram showing a TDM synchronization method between mobile communication base stations according to the present embodiment.

FIG. 4 is a schematic configuration diagram of a conventional conventional TDM synchronization system between mobile communication base stations.

FIG. 5 is a timing chart showing a conventional TDM synchronization method between mobile communication base stations.

[Explanation of symbols]

1, 1 '... Central base station, 2, 2' ... Peripheral base station, 3
... Phase correction antenna, 4 ... Peripheral base station antenna,
5 ... Receiver, 6 ... Phase corrector, 7 ... Transmitter, 1
0 ... Synchronous circuit section, 11 ... Phase delay correcting section, 12 ... Phase delay detecting section, 13 ... GPS receiving section, 14 ... GPS antenna, 15 ... PLL, 16 ... UW detecting section, 20
... GPS satellites

Claims (3)

[Claims] 1. Each peripheral base station receives a ringing signal and GPS time from a GPS satellite using satellite communication,
A GSP clock is generated based on the PS time, the delay time of the calling signal is detected with the generated GPS clock as a reference, and based on the count number for the time obtained by subtracting the delay time from the cycle time of the GPS clock. TD between mobile communication base stations characterized by correcting the phase delay of the ringing signal and transmitting the ringing signal toward a receiver after correction
M synchronization method. 2. A central base station transmitting a calling signal, a calling signal transmitted from the central base station via a relay line, and GPS time received from a GPS satellite using satellite communication, A GPS clock is generated based on the GPS time, the delay time of the ringing signal received based on the GPS clock is detected, and the count number for the time obtained by subtracting the delay time from the cycle time of the GPS clock is used as the basis. And a plurality of peripheral base stations that correct the phase delay of the ringing signal and transmit the ringing signal to the receiver after correction. 3. A peripheral base station receives GPS time transmitted from a GPS satellite using satellite communication,
A GPS receiver that generates a GPS clock based on time, a first detector that detects a unique word of a calling signal received from a central base station, and outputs a unique word detection signal, the GPS clock and the unique word A second detection unit that detects the delay time of the ringing signal based on the GPS clock from the detection signal and further outputs the count number for the time obtained by subtracting the delay time from the cycle time of the GPS clock as phase delay information. And a delay correction unit that temporarily stores the ringing signal received from the central base station and corrects and outputs the phase delay of the ringing signal that is temporarily stored based on the phase delay information, and outputs from the delay correction unit. 3. The TDM synchronization between mobile communication base stations according to claim 2, further comprising: a transmission unit that transmits the generated ringing signal toward a receiver. Stem.