JPH0477130A - Radio paging system - Google Patents

Abstract

PURPOSE:To prevent strong influence in the operation of a system from either change of the delay characteristics of data speed and data lines by shifting the source of radio data transmission timing from a central paging processor to a base station. CONSTITUTION:A paging processor 3 makes the string for input calling, the calling is arranged to be encoded, and the calling is decided by the contents of the data base held in the paging processor 3 to be transmitted to the group of a transmitter on selected radio channel or the like. Further, the paging processor 3 transmits a command to the transmitter to execute transmission in specified time referring to a master timing unit 4. A base station controller 11 of the base station of a type 1 communicates with the paging processor 3 through a data network 5, and controls a transmitter 12 and a master reference oscillator 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to quasi-synchronous transmission of wide area wireless paging systems using any digital modulation method.

A means is disclosed for such a paging system to transmit semi-synchronous broadcasts when the data provided to each transmitter is transmitted over a data network with multiple transmission delays of variable and unknown length.

[Conventional technology]

Existing wide area paging systems use "quasi-synchronous" techniques to reduce data distortion in areas where overlapping reception from two or more transmitters of the paging system is possible. This method ensures that after wireless transmission, the data demodulated in the overlapping area will be in the same phase.
It is necessary for the data to be provided to the demodulators of each of the transmitters timed with respect to each other.

To accomplish this synchronization, some systems use a closed network of data buses with a fixed delay plus additional adjustable delay elements to transmit modulated signals from a common data point of origin to various transmitters. , returning the received signal from a dedicated synchronous receiver to the same point in the network.

At this point in the network, often at a central paging processor point, the output and input data phases are compared and any differences in data phase are corrected by adjusting adjustable delay elements in the transmission line to the transmitter. Delay errors are detected and delay elements are adjusted.

This procedure of measurement and adjustment, in existing systems,
It repeats at least on the order of seconds or minutes and is suitable for compensating for line delay variations over long periods of time.

To control the synchronization procedure, existing systems send various operational and maintenance messages from a central paging processor to a transmitter. In response to the transmitter and synchronous receiver, a fault alert is sent to the central paging system.

[Problem to be solved by the invention]

Systems using current closed-loop synchronization techniques require that all data transmission lines in the closed loop have the same data rate as transmission on the wireless portion of the network, so that correct phase compensation is made between the output and input data. The disadvantage is that data transmission must be maintained at This precludes the use of other characteristic data networks, such as lines with slow data speeds.

Existing systems also require that the delay characteristics of the data network remain approximately between successive synchronization procedures such that synchronization or no synchronization is lost before the other synchronization procedures can adjust the delay elements to correct the delay changes. need to remain constant. This prevents the use of data networks with unpredictable variable delay characteristics, such as packet networks.

Existing systems are unable to generate a wireless transmission data clock at the wireless base station. This is because existing base stations do not include data clocks that synchronize to other base stations to provide semi-synchronous broadcasting.

Existing synchronous receivers are not able to evaluate the synchronization state of the received signal. Because they lack advanced signal processing, they lack a local timing reference of known phase characteristics compared to the received transmission.

Existing systems do not allow messages to be sent to a paging processor advising the synchronization status of incoming transmissions;
To process further messages and adjust the phase of the data clock at the base station into synchronization,
It is only possible to transmit to a base station that can respond to that transmission.

[Means to solve the problem]

The present invention removes reliance on the precise delay characteristics of terrestrial data transmission networks by moving the source of wireless data transmission timing from the central paging processor to the base station. Therefore, neither the data rate nor the variability of the delay characteristics of the data line will affect the operation of the system.

To achieve synchronized data transmission from the base station, the present invention includes other such lock-synchronized data reference oscillators that control the wireless transmission to adjacent areas within the system.

To measure the synchronization performance of a particular transmitter, the present invention
Place a synchronized reference oscillator in the synchronous receiver. A synchronous receiver has the ability to measure the received signal relative to a reference oscillator and analyze the signal to determine the phase difference.

Additionally, the invention includes operational and maintenance messages for enabling communication of synchronization measurements made at the synchronization receiver to the paging processor and for messages commanding remote data reference oscillator adjustments made from the paging processor to the remote oscillator.

〔Example〕

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

Referring to FIG. 1, a paging system according to one embodiment of the present invention is implemented in a public switched telephone network (PST).
N) 1, a radio paging terminal (RPT) 2, a paging processor (PP) 3, and a master reference unit (
MRU) 4 and type 2 base station (BS)
6 and 8, and a type 1 synchronous receiver (SRE) 7,
It consists of a type 2 synchronous receiver (SRE) 9, a type 1 base station (BS) 10, and a data communication network (DCN) 5.

The structure of the wireless paging terminal 2 is that of a conventional telephone switching device with various inputs from the PSTN and other networks, and operates in a manner well known to those skilled in the art.

Calls received into the system by wireless paging terminal 2 are routed to paging processor 3, which is a general-purpose computer processing device with high processing power and specialized input/output equipment, as is well known to those skilled in the art. Consisting of The paging processor queues the incoming calls, sequences and encodes the calls, and dispatches the calls to a group of transmitters over a selected radio channel, etc., as determined by the contents of a database maintained in the paging processor. have the ability to Furthermore, with reference to the master timing unit 4, the paging processor 3 sends commands to the transmitter to carry out certain transmissions at specific times.

The attached master reference unit 4 is further depicted in FIG. 9 and includes a master reference oscillator (MRO) 37;
It consists of an interface processor (IF) 39 and a real time reference (RTR) 38.

The master reference oscillator 37 is depicted in FIG. 7 and consists of an ultra-high stability oscillator (O5C) 31, a phase adjustment circuit 32 connected thereto, and a frequency divider circuit (FDN) 33 connected thereto. Phase adjustment circuit 32 can adjust the phase of the signal from 31 to match that of an input from external to the paging system, real time reference 38 (FIG. 9), on command. This real-time reference may be of any type (e.g., provided by a satellite positioning system, which are well known to those skilled in the art).

A type 1 base station is further depicted in FIG. 2 and includes a base station controller (BSC) 11.
, an RF transmitter (TX) 12, and a master reference oscillator (
(MRO) 13 and a real time reference (RTR) 14. The base station controller 11 communicates with the paging processor 3 via the data network 5 to control the operation, ie, the transmitter 12 and the master reference oscillator 13. Master reference oscillator 13 provides the data clock signal necessary to clock paging messages received from paging processor 3 from base station controller 11 to transmitter 12 at the correct data rate and phase for semi-synchronous broadcasting. do. This is because the master reference oscillator 13 is the real time reference oscillator 1.
This is because it is connected to 4.

A Type 2 base station is further depicted in FIG. 3 and includes a base station controller (BSC) 15.
, an RF transmitter (TX) 16, and a slave reference oscillator (
SRO) 17.

The type 2 base station consists of the type 1 base station depicted in Figure 2 and the slave reference oscillator 1.
The only difference is that 7 replaces the master reference oscillator 13 and real-time reference 14. This requires that commands from the paging processor 3 must be sent via the base station controller 15 to the slave reference oscillator 17 in order to maintain the correct data rate and phase for semi-synchronous broadcasting. .

The slave reference oscillator is further depicted in FIG. 6 and includes a variable frequency oscillator (O5C) 27, a phase adjustment circuit 28,
Frequency divider circuit (FDIV) 29 and frequency control circuit (FCO
NT) consists of 30. Oscillator 27 generates a signal whose frequency is changed by a command from an external controller (eg, base station controller 15) to frequency control circuit 30. Furthermore, the phase of this signal is
By command, as described above, the phase adjustment circuit 28
will be changed. This signal is then divided by frequency divider 29 to the correct frequency for use by the external device.

A type 1 synchronous receiving device is further depicted in FIG.
A synchronous receiver controller (SRC) 1g, a phase comparison processor (PCP) 19, a receiver (RX) 20, a master reference oscillator (MRO) 21, and a real-time reference unit (R
TR) consists of 22.

A master reference oscillator 21 and a real-time reference 22 are used to generate data clock signals in a manner similar to that described in type 1 base stations. This data clock has the same speed and phase as the data clock provided for clocking the transmitted data at such base stations and is therefore received from the receiver 20 to determine the phase error of the demodulated signal. It is compared with the demodulated signal. This phase comparison is performed by a phase comparison processor 19, which is a digital signal processor or other type of equivalent device.

The results of the phase comparison are passed from the phase comparison processor to the paging processor 3 via the synchronous receiver controller 18 and the data communications network 5.

A type 2 synchronous receiving device is further depicted in FIG.
It consists of a synchronous receiver controller (SRC) 23, a phase comparison processor (PCP) 24, a receiver (RX) 25, and a slave reference oscillator (SRO) 26. This device operates similarly to the Type 1 synchronous receiver described above, except that the slave reference oscillator 26 must be correctly adjusted in data rate and phase by commands from the synchronous receiver controller 23. This procedure is accomplished by receiving a signal of known correct data phase from the receiver 25, in which case the phase comparison result by the phase comparison processor 24 is transmitted to the slave reference oscillator 26.
is the phase error of This phase error is passed from phase comparison processor 24 to synchronous controller 23, which can properly adjust the phase and frequency of slave reference oscillator 26.

The synchronous receiver is further depicted in FIG. 8 and includes an RF amplifier circuit (RFA) 34 and a frequency down converter circuit 35.
(FCONV) and a demodulation circuit (DEMOD) 36. The operation of this receiver is conventional, with the wireless paging signal being input to an RF amplifier 34, down-converted in frequency, and sent to a conventional demodulator 36 of a type suitable for demodulating the modulation scheme used by the paging system. Supplied. The demodulated data is provided from the receiver to other circuits for further processing.

The operation of the paging system for normal message transmission is as follows with reference to FIGS. 1-9. The system is not limited to any particular type of paging code, and this discussion applies to codes such as - POC3AG and ERMES.

The message is received by the system by the wireless paging terminal 2 and passed to the paging processor 3. The paging processor checks the call attributes stored in its database, such as which RF channel and which transmitter the call is to be broadcast, and routes the call over the data network 5 appropriately. This phase of operation is conventional and includes such call encoding if necessary, and is well known to those skilled in the art.

Some paging codes require paging batches to be transmitted over the wireless medium at precise times. To ensure that the invention does this, the paging processor performs the following steps (see Figure 10a):
.

In the paging processor 3, a queue of messages to be sent to a particular batch is formed (step 1) and when the queue is full, the current real time is loaded from the master reference unit 4 (step 2).
), this time is adjusted by adding a processing and transmission delay Td. FIG. 10b shows Td, which consists of three components: the time Tep needed to complete the process in the paging processor, the maximum time delay Tt taken for transmission on the data network 5, and the paging at the base station. This is the sum of the time Tab required to complete the process. In step 4, the current real time plus Td is encoded into the paging call and becomes the scheduled transmission time. The call is then transmitted over the data network 5 (step 5), received by the base station and further encoded (step 5).
Step 6), placed in the output queue (Step 7)
. The base station uses its reference oscillator (e.g. M
R013 (FIG. 2) or 5ROI7 (FIG. 3)) and the scheduled transmission time contained in the call as received from the paging processor 3 on the wireless medium at the exact scheduled transmission time. Clock the paging data (step 7).

The invention described above provides a master reference oscillator, which is also included within the system, a number of slave reference oscillators in the base station and a synchronization receiver that must be periodically adjusted to maintain their phase relationship in synchronization with each other. a reference oscillator. The steps required to synchronize these reference oscillators will now be described with reference to the flowcharts of FIGS. 1-9 and 11. Figure 13 shows the assumed radio broadcasting and transmission order for this example, with 2A
continues.

The paging processor 3 schedules an interval with respect to a known period during which the slave oscillator remains in synchronization during the initiation procedure, the customer traffic is carried by the network at a particular instant, and the customer call is sent whenever possible. It is preferable to use spatial radio time in preference to shifting
Step 1).

The paging processor 3 also identifies the geographical locations of all base stations and type 1 and 2 synchronization receivers with respect to their ability to send and receive calls from each other. This radio broadcast database is then consulted to determine an optimally fast and accurate synchronization sequence (step 2). Each synchronization train begins with reference to a Type 1 base station or a Type 1 synchronous receiver specified by the database and progresses through Type 2 base stations and synchronous receivers as follows.

Suppose, as in the example using Figure 1, that the database specifies the following columns: Type 1 base station 10 is selected as the out-of-synchronization reference. The paging processor 3 makes specific paging calls for synchronization to be sent only by the base station 10. The address portion of this call is the specified pager address, and the message portion contains appropriately selected data as synchronization data and certain message elements for control of the synchronization procedure (step 3).

The paging processor 3 places this call at the end of the queue waiting for the call to be sent, and then
Determine the scheduled transmission time as described above for the normal call queue (step 4).

These calls are then sent from the paging processor 3 to the base station as usual (step 5). Among the special information contained in the synchronization message (FIG. 11b) is the identification of the transmitter (in this example the station 10) for broadcasting the synchronization message. Upon receiving a group of messages from paging processor 3, base station controller 1
1 checks the existence of a synchronization message (step 6).

If no synchronization message is included, then normal encoding and transmission occurs as described above (step 8). If a synchronization message is included, the base station checks whether its own identification number is included in the message (step 7). If the identification number is not included, then a regular message and all addresses must be transmitted instead of a synchronization message (step 9). If a base station 1 separate number is included in the synchronization message (eg, a base station 10 identifier), then the entire message must be encoded and transmitted as usual (step 10). This allows base station 10 to perform isolated transmission of synchronization messages (transmission IA in FIG. 13).

At the same time, when the operations described above occur, the paging processor sends operational and maintenance messages to the synchronization receiver (e.g. synchronizer 9) specified by the radio broadcast database.
(step 11). This message informs the synchronization receiver of the impending transmission of a synchronization message from the base station 10 and the scheduled transmission time of that transmission.

The procedure of the synchronous receiving device will be explained (see FIG. 12 and FIG. 5). After receiving the message from the paging processor 3 by the synchronous receiver controller 23, alerting the synchronous message from a particular base station at a particular time step l), the synchronous receiver waits for pending transmissions (step 2). When a transmission is received at or near the advised time, receiver 25 demodulates the signal and passes the data to a phase comparison processor, where the phase of the data bits in the synchronization message is compared with the clock from slave reference oscillator 26. (Step 3). Since sufficient real-time information of the time of synchronous transmission is passed to the synchronous receiver, this phase comparison is not limited to 1/-0.5 bit delay, but can be extended to any degree beyond this for correction of large timing errors. Detect timing errors for In this example, the transmission is scheduled from a Type 1 base station,
The slave reference oscillator 26 is the target to be adjusted because it is received by a type 2 synchronous receiver. Therefore, the phase error detected in step 3 is the error of the synchronous receiver's own slave reference oscillator 26. The paging processor informs the synchronizer during step 1 that the synchronizer's own slave reference oscillator 26 is to be adjusted.

The synchronous receiver controller 23 therefore issues a command to modify the timing of the slave reference oscillator 26 (steps 4 and 5). At this point, it is considered that the synchronous receiving device 9 has been correctly synchronized.

If in step 1 the paging processor has informed the synchronization receiver that its own slave reference oscillator should not be adjusted, then the measured phase error must be transmitted to the paging processor on the data network 5. (Steps 4 and 6)
.

During this transmission IA, the paging processor 3 may schedule another transmission IB (FIG. 13).

This is because there is no wireless broadcast between devices 6/7 and 8/9/10. In the case of transmission IB, the synchronization receiving device 7 receives the synchronization signal from the base station 6. This is because the master oscillator is included in the synchronization receiver 7 and the base station 6 has a target slave reference oscillator to be synchronized. Therefore, when the synchronizer 7 determines the phase error of the transmission IB, this error information is used by the paging processor 3 so that the adjustment data is sent to the correct slave oscillator (i.e. in 6).
must be sent to. After base station 6 receives the message to adjust its slave reference oscillator, it is considered to be properly synchronized.

Transmission 2A (Figure 13) shows how a previously synchronized slave oscillator is used to synchronize other slave oscillators and thus how to increase the overall broadcast of the synchronized part of the system. It shows that. Knowing from the database the schedule of the synchronization procedure that the synchronization receiver 9 was previously synchronized by the transmission IA, the paging processor 3 transmits the synchronization transmission 2A to the base station 8.
from there to the synchronous receiver 9. Similar to the transmission IB example above, the phase error measured by the synchronous receiver 9 is the phase error of the base station oscillator (base station 8). Therefore, the synchronous receiver 9 must communicate the measured phase error to the paging processor 3 so that a message can be sent to adjust the slave reference oscillator included in the base station 8.

After an adjustment message to the base station 8 is sent from the paging processor, the base station 8 is considered to be properly synchronized.

The above example has shown how a properly selected sequence of synchronization transmissions and oscillator adjustment messages synchronize all slave reference oscillators within one or multiple broadcast regions.

〔Effect of the invention〕

The present invention allows for the construction of wide area digital radio paging networks using semi-synchronous broadcasts interconnected over land by data transmission systems that operate without taking into account any data rate or delay characteristics of the system. This can also be used for packet data type data transmission networks.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a paging system, Fig. 2 is a block diagram showing a type 1 base station, Fig. 3 is a block diagram showing a type 2 base station, and Fig. 4 is a block diagram showing a type 1 synchronous receiving device. Block diagram shown,
Fig. 5 is a block diagram showing a type 2 synchronous receiver, Fig. 6 is a block diagram showing a slave reference oscillator, Fig. 7 is a block diagram showing a master reference oscillator, and Fig. 8 is a block diagram showing a synchronous receiver. , FIG. 9 is a block diagram illustrating the master reference unit, FIG. 10a is a flowchart illustrating the sequence of events in the paging processor associated with forwarding a group of conventional paging messages to a base station, and FIG. Figure 11g showing the delay with the total delay mentioned in
11b is a flowchart showing an example of events in the base station device related to transmission of a group of paging messages, FIG. 11b is a diagram showing the contents of a synchronization message, and FIG. 12 is a synchronization receiving device related to reception and analysis of the synchronization message. FIG. 13 is a flowchart showing an example of an event in FIG. 13, and FIG. 13 is a diagram showing an example of a synchronous transmission sequence. 1...Public Switch Telephone Network (PSTN) 2
... Radio paging terminal (RPT), 3... Paging processor (PP), 4... Master reference unit (MRU), 5... Data communication network (DCN), 6... Type 2 base Station (BS) 7...Type 1 synchronous receiving device (S R
E) 8...Type 2 base station (BS),
9... Type 2 synchronous receiver (SRE), 10.
・Type 2 base station (BS), 11...
・Base station controller (ESC), 12・
...Transmitter (TX), 13...Master reference oscillator (
MRO), 14...Real time reference (RTR), 1
5...Base station controller (E
S C) 16... Transmitter (TX), 17... Adjustable slave reference oscillator (SRO), 18... Synchronous receiver controller (SRC), 19... Phase comparison processor (PCP), 20...Synchronous receiver (RX)
, 21... Master reference oscillator (MRO), 22...
... Real time reference machine (RTR), 23... Synchronous receiver controller (SRC), 24... Phase comparison processor (PCP), 25... Synchronous receiver (RX), 2
6. , Slave reference oscillator (SRO), 27... Adjustable oscillator (OSC), 28... Phase adjustment circuit, 29... Frequency division circuit (FDIV), 30... Frequency adjustment circuit (FCONT) , 31... Master oscillator (OSC), 32... Phase adjustment circuit, 33...
Frequency divider circuit (FDIV), 34...RF amplifier (RFA
), 35... frequency converter (FCON), 36...
... Paging demodulator (DEMOD), 37... Master reference oscillator (MRO), 3811. Real time reference (RTR), 39...interface processor (
IP), Tep...time to complete encoding in the paging processor, Tt...maximum time required to transmit the call to the base station, Teb
...Time to complete encoding at the base station. Fig. 1 Paging system Fig. 2 Fig. 3 Type 2 base station ff 16 Fig. Slave reference oscillator Master reference oscillator RTR and controller Fig. 8 Receiver Fig. 9 To master reference unit PP Fig. 10a To TX column Td Total delay Figure 12 Synchronization receiver procedure Figure 11a Opening message/message transmission Figure 11b Synchronization message contents Four ro=]
Figure 13 Period Example

Claims (1)

[Claims] 1. A wireless paging terminal switching device capable of interacting with the public switched telephone network and other communication networks, together with a master reference unit, providing central control of the paging system and base paging calls and other information. a paging processor for distributing operational and maintenance messages to and from each base station and synchronization receiver to and from each base station and synchronization receiver; and a paging processor for timing encoded paging messages on the wireless medium. a plurality of wireless base station devices for receiving and transmitting paging messages; and a plurality of synchronization receivers for receiving paging messages from a wireless medium and analyzing timing characteristics thereof; a subset includes an adjustable oscillator whose phase and frequency are adjusted by commands from the paging processor; the remaining base stations and receivers include fixed reference oscillators; , a paging processor and a data transmission system connecting such that bidirectional communication between one or a defined group of base stations and a synchronous receiver is achieved. 2. The paging processor further receives paging calls from the wireless paging terminal, arranges, times, and encodes the calls into a format to be transmitted to the base station device, and initiates a base station synchronization procedure. 2. The wireless paging system of claim 1, further comprising means for performing central control of the paging system including arranging and determining and transmitting and receiving operational and maintenance messages to and from all other connected devices in the system. system. 3. The base station including a fixed reference oscillator is
The base station further includes a processor that communicates with and interacts with a paging processor, encodes general and specific synchronization paging messages, and changes the phase of the master oscillator and receives its clock signal;
2. The wireless paging system of claim 1, comprising a fixed oscillator or master oscillator, a real time reference for adjusting said master reference oscillator in real time, and a wireless transmitter for broadcasting a wireless paging signal. 4. The base station, which includes an adjustable reference oscillator, further communicates and interacts with the paging processor, encodes regular and specific synchronization paging messages, changes the phase and frequency of the slave oscillator, and changes its clock signal. 2. The wireless paging system of claim 1, further comprising a processor for receiving a wireless paging signal, said base station also having an adjustable oscillator or slave oscillator, and a wireless transmitter for broadcasting a wireless paging signal. 5. The synchronous receiving device including a fixed reference oscillator further includes a processor in communication with and interacting with a paging processor to change the phase of the master oscillator and receive the clock signal thereof, and the synchronous receiving device also includes: a fixed oscillator or master oscillator; a real-time reference for adjusting said master reference oscillator in real time; a receiver for receiving and demodulating the wireless paging signal; and a time delay between the received paging data and the master reference oscillator. and a phase comparison processor for calculating . 6. The synchronous receiving device includes an adjustable reference oscillator,
further comprising a processor communicating and interacting with the paging processor to change the phase of the slave oscillator and receive its clock signal, said synchronous receiving device also comprising an adjustable oscillator or slave oscillator and a wireless paging signal 2. The wireless paging system of claim 1, comprising: a receiver for receiving and demodulating paging data; and a phase comparison processor for calculating a time delay between the received paging data and the master reference oscillator. 7. The wireless paging system of claim 1, wherein the master oscillator further comprises: a high stability oscillator connected to a phase adjustment circuit adjusted by an external processor and a real-time reference, and a frequency output divider circuit. 8. The wireless paging system of claim 1, wherein the slave oscillator further comprises: a high stability oscillator connected to a phase adjustment circuit adjusted by an external processor, and a frequency output divider circuit adjusted by the external processor. 9. The master reference unit further comprises a real-time reference unit connected to the master reference oscillator and connected to an interface processor that controls the operation of the master reference oscillator and provides a resulting clock signal to an external device. Wireless paging system described. 10. The receiver further includes an RF signal connected to a frequency conversion circuit connected to the demodulation circuit.
The wireless paging system according to claim 1, further comprising an amplifier circuit. 11. The wireless paging system of claim 1, wherein a message is sent to notify the synchronous receiver of the exact real time at which the wireless paging transmission is scheduled to be received at the synchronous receiver. 12. The wireless paging system of claim 1, wherein the plurality of slave reference oscillators are configured such that the phase of the oscillators is automatically adjusted to provide accurate quasi-synchronous transmission in a particular transmission overlap region. 13. A claim in which multiple slave reference oscillators have a phase referenced to the master oscillator by measuring wireless data transmissions that are clocked by other oscillators and demodulated and analyzed for timing and phase by a synchronous receiver. The wireless paging system according to item 1. 14. The data communications network includes a central paging processor and individual and group base station controllers for adjusting the phase and frequency parameters of the slave reference oscillators in addition to other operational and maintenance functions;
2. The wireless paging system of claim 1, wherein the wireless paging system enables communication between individual and group synchronous receiver controllers. 15. The wireless paging system of claim 1, wherein the data communications network enables communication from the central paging processor to the individual base station controllers to request specific synchronous transmissions transmitted in accurate real time. 16. The data communications network schedules a synchronization procedure;
2. The wireless paging system of claim 1, wherein communication is enabled between the central paging processor and the individual synchronous receiver controllers for communicating results determined by the synchronous receivers to the paging processor. 17. The paging processor is outside the radio propagation range of the transmitter connected to the master reference oscillator, but within range of the base station containing the previously synchronized slave reference oscillator, correct for broadcast to the synchronized receiver. The synchronization procedure is efficiently scheduled so that a logical pattern of correctly adjusted slave reference oscillators used to generate timing transmissions is formed, thereby allowing the use of a small number of master reference oscillators to 2. The wireless paging system of claim 1, wherein multiple base stations in a paging area are synchronized.