JPH0524692B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] In a paging system in which a different frequency is assigned to each region and a pager receiver performs paging communication, a preamble word that can identify the frequency corresponding to the region is added to each transmission. The pager receiver is equipped with a preamble word detection means and a receiving frequency selection means, and receives a modulated wave signal of a frequency corresponding to the detected preamble word, thereby allocating a frequency for a wide area. This allows calling communications even when moving to any area without having to worry.

[Industrial application field]

The present invention relates to a wide area wireless communication system that performs paging communication using a pager receiver equipped with reception frequency selection means.

In a paging system, a modulated wave signal of the same frequency is transmitted from multiple transmitting stations connected to a central station, and paging communication is performed for pager transmitters within the service area of each transmitting station. Different frequencies are assigned to each region, and therefore, when a pager receiver for use within one region is moved to another region, paging communication cannot be performed.

Therefore, by using a regional frequency and a wide-area frequency common to each region, a pager receiver that can receive the regional frequency can perform paging communication within each region and receive the wide-area frequency. There is a system that uses a wide area pager receiver to enable paging communications even when moving to a different area. In that case, it is necessary to use two types of frequencies, one for local and one for wide area, and two types of pager receivers, one for local and one for wide area. It is requested.

[Conventional technology]

In the conventional wide area wireless communication system, for example, as shown in FIG.
11 to T23 are connected, and the transmitting stations T11 to T13
Region L1 is covered by the service area of
The location and number of each transmitting station are selected so that the service area of the transmitting stations T21 to T23 covers region L2.

Further, frequency F1 is assigned to region L1, frequency F2 is assigned to region L2, and frequency Fc is assigned for wide area use. Also, central stations C1 and C2
They are connected by a line 100, and wide area calling signals are transferred. Further, 101 and 201 are connected to the central stations C1 and C2, respectively, and the subscribers 102 and
This is an exchange that accommodates 202. Furthermore, if the pager receiver P1 is used for a local area and the pager receiver P2 is used for a wide area, the pager receiver P1 has a configuration that can receive the frequency F1 for the area L1, and the pager receiver P2 can receive the frequency Fc. It has a structure.

For example, when calling the pager receiver P1 from the subscriber 102 via the switching center 101,
Since this pager receiver P1 is registered in the switching center 101 as a regional call signal, a call signal for the region is transferred to each transmitting station T11 to T13 via the central station C1, and a modulated wave signal of frequency F1 is transmitted. will be done. Thereby, pacer receiver P1
A call communication is performed.

Furthermore, when the subscriber 102 calls the pager receiver P2 via the switching center 101, since the pager receiver P2 is registered in the switching center 101 as a wide-area receiver, The paging signal for each region L2 is transferred to each transmitting station T11 to T13, and is also transferred to the central station C2 in another area L2 via the line 100, and the paging signal is transferred to each transmitting station T21 to T13.
The calling signal is transferred to ~T23. Then, a modulated wave signal having a wide area frequency Fc is transmitted from each of the transmitting stations T11 to T23. Therefore, even if the pager receiver P2 moves from the area L1 to the area L2, it is possible to perform paging communication.

Also known is a method in which the pager receivers P1 and P2 are provided with a character display device or the like, and in addition to making a call by sounding a buzzer or the like, simple character information is transmitted and displayed.

Further, the format of the modulated wave signal transmitted from each transmitting station T11 to T23 is, for example, eight data D11 compatible with a pager receiver, as shown in FIG.
. . . D18 are designated as a batch B1, and similarly, eight pieces of data Dn1 to Dn8 are designated as a batch Bn, and a preamble word PW consisting of a synchronization signal is added to the beginning of each batch. If the final batch does not contain eight pieces of data, dummy data is added so that there are eight pieces of data. These communication speeds are
For example, 512 b/s.

FIG. 6 shows a block diagram of the main parts of a conventional transmitting station, in which 300 is a transmitting station, 301 is a regional transmitter,
302 is a wide area transmitter, 303 and 304 are antennas, and 305 and 306 are signal lines. A calling signal for the local area is transferred from the central station via the signal line 305, and a modulated wave signal in the format shown in FIG. 5 is transmitted from the transmitter 301 at the local frequency F1 or F2. Also, a wide area calling signal is transferred from the central station via the signal line 306, and sent to the transmitter 302.
A modulated wave signal in the format shown in FIG. 5 is transmitted from the wide-area frequency Fc. The antennas 303 and 304 can be provided separately for local and wide areas, but they can also be shared via a combiner.

[Problem that the invention seeks to solve]

In the conventional paging system, in addition to the local frequencies F1 and F2, a wide area frequency is used.
Since it allocates Fc, there is a problem in terms of effective use of frequencies. It is also necessary to manufacture two types of pager receivers P1 and P2, one for local use and one for wide area use. Further, since the transmitting station 300 needs to be provided with transmitters 301 and 302 for local and wide areas, the installation space for these becomes large and the cost increases.

Furthermore, it is necessary to install two signal lines 305 and 306, one for local and one for wide area, between the central station and each transmitting station, which has the disadvantage of making the system expensive.

An object of the present invention is to enable wide area wireless communication without allocating frequencies for wide areas.

[Means for solving problems]

The wide area wireless communication system of the present invention uses a pager receiver having a function of selectively receiving frequencies, and will be explained with reference to FIG.

Each transmitting station Tji (j, i=1, 2, 3, ...) is distributed and connected to the central station Cj, and the central stations Cj are also connected by a line,
A different frequency Fj is assigned to each region Lj. Each transmitting station Tji transmits a modulated wave signal to which a preamble word indicating the assigned frequency of each region Lj is added. Also, the pager receiver Pk (k=1,
2, 3, ...) is provided with a selection means 1 for scanning and selecting reception frequencies and a preamble word detection means 2, the detection means 2 detects and identifies a preamble word, and determines the assigned frequency indicated by this preamble word. When the receiving frequency and the receiving frequency match, the selection means 1 stops scanning, selects the receiving frequency and the receiving frequency, and receives the modulated wave signal from the transmitting station Tji.

[Effect]

To a pager receiver for a region, a modulated wave signal corresponding to a paging signal is transmitted only from a transmitting station within that region, and to a pager receiver for a wide area, a paging signal is transmitted via a line between central stations Cj. is transferred, and modulated frequency signals based on their assigned frequencies are transmitted from all transmitting stations Tji. Also pager receiver
Pk selects a receivable frequency by the reception frequency selection means 1, detects a preamble word by the detection means 2, and controls the selection means 1 to receive the frequency indicated by the preamble word. do. Therefore, even if the pager receiver Pk moves to a different area, it can receive the allocated frequency for that area, so wide area communication is possible without allocating a frequency for wide area use. When the scanning reception frequency by the selection means 1 matches, scanning is stopped and reception is performed, so even if a modulated wave signal etc. from another system using the same frequency band in the vicinity or in the same area is received, scanning is not performed. will continue, therefore,
Only modulated wave signals from the same system can be reliably received without interference from other systems.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an explanatory diagram of an embodiment of the present invention, showing the configuration in regions L1 to Ln, and
The location of transmitting station Tji is selected so that Lj is covered by the service area of a plurality of transmitting stations Tji, and each is connected to central station Cj by a public line or the like. The central stations Cj are also connected via public lines, etc.

The pager receiver Pk also includes reception frequency selection means 1 and preamble word detection means 2. Note that a pager receiver for a region can be configured to be able to receive only the assigned frequencies of the region. Note that j, i, k are 1,
2, 3,...

From the transmitting station Tji, as shown in FIG. 2, the preamble word PW is followed by batches B1, B2,...
A modulated wave signal is transmitted in a format consisting of..., and its preamble word PW is
It includes a synchronization signal and an identification signal, and for example, in region L1, "x...x001" (x is arbitrary) is inserted as an identification signal indicating the allocated frequency F1. Similarly, the identification signal in area L2 is "×...×010", the identification signal in area L3 is "×...×011", and the identification signal in area L4 is "×...×100". is inserted. Each batch B1, B2, . . . is composed of data corresponding to eight pager receivers, as described above.

The pager receiver Pk has, for example, the configuration shown in FIG. 3, where 1 is a receiving frequency selection means, 11 is a mixer, 12 is a demodulator, 13 is a synthesizer, 14 is a counter, and 15 is a control unit. Part, 2
21 is a decoder, and 22 is a detection identification unit. The reception signal selection means 1 includes a mixer 11, a demodulator 12, a synthesizer 13, a counter 14, and a control section 15, and shows a case in which the reception frequency is selected by switching the frequency of the output signal of the synthesizer 13. . Further, the detection means 2 is constituted by a decoder 21 and a detection/identification section 22, which decodes the demodulated signal and identifies the identification signal in the detection/identification section 22.

A received high frequency signal is applied to the mixer 11 from a high frequency section (not shown). This mixer 11 has
The output signal of the synthesizer 13 is applied as a local oscillation signal, and the intermediate frequency signal output from the mixer 11 is applied to the demodulator 12 and demodulated. When the carrier detection signal at that time is applied to the control section 15, the control section 15 stops the counting operation of the counter 14. The synthesizer 13 switches the output signal frequency according to the contents of a counter 14 that counts clock signals.
When it continues to operate, it is scanning the reception frequency according to the period of the clock signal.
Then, when the operation of the counter 14 is stopped, the output signal frequency of the synthesizer 14 is fixed at the frequency shown in the figure at that time.

Pager receiver registered for regional use,
For example, for paging communication to pager receiver P1 in area L2, modulated wave signals are transmitted only from transmitting stations T21 to T23 connected to central station C2 in area L2 at frequency F2 assigned to that area. . Therefore, even if the Bezier receiver P1 has the receiving frequency selection means 1, when moving to another area, the user cannot receive the calling communication service because the calling signal is not transferred to the other area. You will not be able to do that.

In addition, in paging communication to a pager receiver registered for wide area use, the paging signal is transferred to each central station Cj, so modulated wave signals are transmitted from all transmitting stations Tji at the frequency Fj assigned to that area. Ru. For example, in region L1, each transmitting station T11~
From T13, a modulated wave signal having the signal format shown in FIG. 2 is transmitted at frequency F1. The area L1
If there is a pager receiver Pk in , when the synthesizer 13 scans the reception frequency,
When the modulated wave signal of frequency F1 is received and a carrier detection signal is obtained from the demodulator 12, the control section 15 stops the operation of the counter 14.
1 can be continuously received.

Then, the identification signal of the preamble word PW demodulated by the demodulator 12 is decoded by the decoder 21 and applied to the detection and identification section 22. In this case, the identification signal is "×...×001" and the frequency is F.
1, the identification result is transferred to the control unit 15. The control unit 15 identifies the content of the counter 14 in the stopped state, and if the content is such that the frequency F1 can be received, the control unit 15 determines that the output signal frequency of the synthesizer 13 is correct and maintains the receiving state of the frequency F1. Moreover, if the identification signal has content other than the above-mentioned case, the frequency of the received signal whose carrier was detected first will be different from the frequency F1 assigned to this area L1, so the control unit 15 The operation of the receiver is restarted to scan the receiving frequency. Therefore, since the receiving frequency is not determined only by carrier detection, error-free paging communication is possible.

Also, whether or not the call is to the own pager receiver is determined by each batch B following the preamble word PW.
It can be identified by the pager receiver's assignment code, etc. indicated by the data in 1, B2, . . . . Also, registration as to whether a pager receiver is for a local or wide area is done at the central station Cj or the switching station before it, and in response to a paging communication request for a wide area pager receiver, the paging signal is sent to all central stations. It is transferred to the transmitting station Tji via Cj.

〔Effect of the invention〕

As explained above, the present invention transmits a modulated wave signal to which a preamble word PW indicating the allocated frequency Fj of each region Lj is added from the transmitting station Tji, and detects the preamble word PW by the detection means 2 of the pager receiver Pk. Identify and preamble words
It controls the selection means 1 so that it can receive a modulated wave signal of the frequency indicated by PW, and wide area wireless communication is possible without allocating a wide area frequency, so it is possible to effectively use frequencies. can.

In addition, since each transmitting station Tji only needs to be equipped with a transmitter for one frequency, the central station Cj
Wide area wireless communication becomes possible by simply adding a configuration that connects between the two and transfers a wide area calling signal, making it possible to achieve economicalization. Furthermore, since the pager receiver Pk identifies the allocated frequency Fj of the region Lj by detecting and identifying the preamble word PW in addition to carrier detection, it has the advantage of being able to prevent malfunctions.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram of a signal format of an embodiment of the present invention, FIG. 3 is a block diagram of a main part of a receiver according to an embodiment of the present invention, and FIG. 4 is an explanatory diagram of an embodiment of the present invention. FIG. 5 is an explanatory diagram of a conventional example. FIG. 5 is an explanatory diagram of a signal format of a conventional example. FIG. 6 is a block diagram of a main part of a conventional transmitting station. 1 is a receiving frequency selection means, 2 is a preamble word detection means, Lj is a region, Fj is a frequency, Cj is a central station, and Tji is a transmitting station.

Claims (1)

[Claims] 1. In a wireless communication system in which a different frequency Fj is assigned to each region Lj in which a plurality of transmitting stations Tji are distributed, and paging communication of a pager receiver Pk is performed, the allocation of each region Lj A modulated wave signal to which a preamble word indicating a frequency Fj is added is transmitted from the transmitting station Tji, and the pager receiver Pk includes a selection means 1 for scanning and selecting a reception frequency, and a detection means 2 for the preamble word. The detecting means 2 detects and identifies a preamble word indicating the assigned frequency Fj, and when the assigned frequency indicated by the preamble word and the reception frequency match, the selecting means 1
A wide area wireless communication system characterized in that scanning is stopped, reception selection of the reception frequency is performed, and a modulated wave signal from the transmission station Tji is received.