JPH0497695A - Time division switching system - Google Patents

Abstract

PURPOSE:To prevent interruption of a talking voice for channel changeover at exchange by applying a digital signal to both an address before exchange and an address after exchange for a prescribed time prior to channel changeover. CONSTITUTION:The above system consists of an input terminal 1, plural channel memories 2, an output terminal 3, a write selection switch 4, a read selection switch 5, a read address counter 6, a CPU 16, and a control section 19 including an address 17 before exchange and an address 18 after exchange as address information given to the read address counter 6. Prior to cannel changeover, a digital signal is fed to both the address 17 before exchange and the address 18 after exchange for a prescribed time. Thus, the synchronization acquisition of a voice coding frame is assisted and the time division switching system not causing interruption in the talking voice at exchange is established.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a time division switching system that handles digital signals with long speech encoded frames and in which channel switching is performed even during a call.

[Conventional technology]

FIG. 8 is a block diagram showing a conventional time division switching system. In the figure, l is an input terminal into which a digital signal is input, 2 is a plurality of channel memories in which the digital signals are stored, and 3 is an output from which the digital signal read out from the channel memory 2 is output. It is a terminal. Further, 4 is a write selection switch that controls the connection between the input terminal 1 and each communication path memory 2, and 5 is a successive selection switch that controls the connection between the output terminal 3 and each communication path memory 2.

6 is a successive address counter that instructs the communication path memory 2 to read a digital signal, and 7 is a control section that provides address information to the successive address counter 6. 8
is a central processing unit (hereinafter referred to as CPU) that instructs the control unit 7 to switch channels. Further, 9 is address information given to the read address counter 6 from the control section 7.

Next, the operation will be explained. The digital signal input to the input terminal 1 is written into one of the channel memories 2 selected by the write selection switch 4. The written digital signal is read out in accordance with instructions from the successive address counter 6 in the read cycle, and is outputted to the output terminal 3 via the successive selection switch 5. in this case,
The control unit 7 sends the pre-exchange address as address information 9 to the successive address counter 6, and the communication path memory 2 is read out based on the pre-exchange address.

Here, when it becomes necessary to switch channels, the CPU 8 gives an instruction to perform the exchange to the control unit 7, and upon receiving the instruction, the control unit 7 changes the address information 9 from the address before exchange to the address after exchange. Therefore, from then on, the channel memory 2 is read out based on this exchanged address in accordance with the instructions from the successive address counter 6, and the channel is switched.

Further, FIG. 9 is an explanatory diagram for explaining a conventional time division switching method in a mobile radio system. In the figure, reference numeral 10 is a mobile station such as a digital radio telephone device having a 20m5 voice coded frame, which is mounted on a car or the like.

11 al ~i 1 am and 1lbl ~1lb
ff is a wireless zone in which the mobile station 10 moves, and 12a and 12b are multiple wireless zones 11.
at ~i 1 as or 1lbl ~llb.

This is a group of zones formed by

13a and 13b correspond to this zone group 12a or 12
This is the base station of b. In this base station 13a13b, 14 is a channel switching device equipped with a time division switching circuit similar to that shown in FIG. 8, and 15 is a mobile station 10.
This is a digital wireless transmitter/receiver that communicates with

Next, the operation will be explained. The mobile station 10 moving within the wireless zone 11a+ of the zone group 12a is connected to the base station 13.
Communication is carried out with a using radio waves of frequencies FIT and FIR. The digital signal input at that time is
It is written in one of the channel memories 2 in FIG. 8, and in the read cycle, it is read out in response to instructions from the successive address counter 6 based on the address information 9 (pre-movement address) from the control unit 7.

Here, the mobile station 10 is in the wireless zone 11 of the zone group 12b.
When the mobile station 10 moves beyond the zone group to b1, the mobile station 10
Communication is started on a new channel with the base station 13b using radio waves of frequencies F9T and F9R. In that case as well, the address information 9 is changed from the pre-move address to the post-move address, and subsequent reading of the communication path memory 2 is performed according to instructions from the subsequent address counter 6 based on this post-move address.

[Problem H to be solved by the invention] Since the conventional time-division switching system is configured as described above, synchronization acquisition of the audio encoded frame is not sufficient, and digital signals with long audio encoded frames cannot be handled. , and the channel is switched from the pre-exchange address to the post-exchange address even in the middle of a call, or a digital switch with a long voice-encoded frame is handled, and the mobile station changes the zone group even during the call. If applicable to a time-division mobile radio communication system where channel switching is performed from the pre-movement address in the zone group before movement to the post-movement address in the zone group after movement, channel switching is performed. There was a problem in that the voice of the call would be interrupted every time the call was interrupted.

The invention as claimed in claim (1) has been made to solve the above-mentioned problems, and aims to provide a time division switching method that does not cause interruptions in voice calls due to channel switching during switching. do.

Another object of the invention is to provide a time-division switching method that does not cause interruptions in voice communication due to channel switching when a mobile station moves across zone groups.

(Means for Solving the Problem) The time division switching method according to the invention described in claim (1) supplies digital signals to both the pre-exchange address and the post-exchange address for a certain period of time prior to channel switching. It is.

Further, in the time division switching method according to the invention described in claim (2), when the mobile station is in the zone group before moving, the audio encoded frame is already captured in the zone group to which the mobile station is moving, and after moving, A digital signal is also supplied to the address for a certain period of time.

[For production]

The time-division switching method according to the invention described in claim (1) provides digital signals to both the pre-switching address and the post-switching address for a predetermined period of time prior to channel switching. This realizes a time-division switching system that helps synchronized acquisition of audio encoded frames and eliminates interruptions in call audio during switching.

Further, in the time division switching method according to the invention described in claim (2), while the mobile station is in the zone group before movement, the radio frequency signal of the mobile station is transferred to the zone group to which the mobile station is moving based on the address before movement. received and audio encoded frame 1;
By capturing the mobile station and supplying a digital signal to the address for a certain period of time after the mobile station moves, it helps synchronized acquisition of the voice encoded frame, and prevents interruptions in voice communication even when the mobile station moves across zone groups. Realizes a split-switching method.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a block diagram showing an embodiment of the invention as set forth in claim (1). In the figure, 1 is an input terminal, 2 is a plurality of channel memories, 3 is an output terminal, 4 is a write selection switch, and 5
6 is a continuation selection switch, and 6 is a continuation address counter, which are the same or equivalent parts to those of the conventional system denoted by the same reference numerals in FIG. 8, and detailed explanation thereof will be omitted.

Further, reference numeral 16 is a CPU that is different from conventional CPUs in that when switching channels, it first instructs preparation for the exchange, and then instructs the execution of the exchange after a predetermined period of time has elapsed. 17 is a pre-exchange address as address information given to the successive address counter 6, and 18 is a post-exchange address. Reference numeral 19 is a control unit different from the conventional one in that it simultaneously supplies the pre-exchange address 17 and the post-exchange address 18 as address information to the successive address counter 6 when the CPU 16 instructs to prepare for exchange.

Next, the operation will be explained. The digital signal input to the input terminal 1 is written to one of the channel memories 2 selected by the write selection switch 4, as in the conventional case, and is read by the successive address counter 6 in the read cycle.
is read out according to the instruction, and outputted to the output terminal 3 via the successive selection switch 5. In this case, the pre-exchange address 17 is sent from the control unit 19 to the successive address counter 6, and the communication path memory 2 is read out based on the pre-exchange address 17.

Here, when it becomes necessary to switch channels, the CPU 16 first gives an instruction to prepare for switching to the control unit I9. The control unit 19, which has received this instruction to prepare for exchange, sends the pre-exchange address 17 currently in use as well as the post-exchange address 18 after channel switching to the successive address counter 6. Therefore, during this exchange preparation period, the communication path memory 2 is read out based on these pre-exchange address 17 and post-exchange address 18, and the same information is output to the two channels.

Thereafter, when an instruction to perform the exchange is given from the CPU 16, the control unit 19 stops sending out the pre-exchange address 17, and
After the exchange, only the address 18 is sent to the subsequent address counter 6. Therefore, from then on, the channel memory 2 is read based only on this post-exchange address 18, and the channel switching is completed.

FIG. 2 is a time chart showing the time relationship using a space/time matrix.

In the figure, 20 is a line salt, 21 is a time slot number, 22 is an input address of an input digital signal, and 17.18 is the address before exchange and the address after exchange.

In the write mode, the digital signal written to the input address 22 of the line salt ``B'' and time slot number ``4'' is written to the pre-exchange address 17 of the line salt ``A'' and time slot number ``17'' in the continuous output mode. When the instruction to prepare for exchange arrives, the digital signal written to the input address 22 is not limited to the pre-exchange address 17 (the line salt "F" and the time slot number "12" after the exchange). It is also read by the address 18. Furthermore, when an instruction to carry out the exchange arrives, reading by the pre-exchange address 17 is stopped, and reading is performed only by the post-exchange address 18.

In the above embodiment, the communication path memory is read in accordance with the instructions of the successive address counter, but a demultiplexing gate array may also be used.

FIG. 3 is a block diagram illustrating such an embodiment. In the figure, 23 is a gate array for multiplexing and demultiplexing, 24 is a channel address (hereinafter referred to as CH address) receiver that receives instructions for exchange preparation and execution and gives multiplexing instructions to the multiplexing and demultiplexing gate array 23; is a CH address designation counter of the demultiplexing gate array 23, 26
is also an address register of the demultiplexing gate array 23.

Also, Figure 4 is a time chart showing the time relationship.
Demultiplexing game 1-array 23 that multiplexes digital signals from #ICH to #nCH on one time axis.
is shown. Address ゛'9 on the time axis now
”, when the CH address receiver 24 is instructed to prepare for exchange to switch the address to the address “1 day” for the #2 CH which is currently talking, the CH address receiver 24 receives the digital signal of the #2 CH. address"
It instructs not only address "9" but also address "18" to be multiplexed at the same time. After that, when receiving an instruction to perform the exchange,
The CH address receiver 24 instructs the demultiplexing gate array 23 to stop multiplexing to address "9" and continue multiplexing only to address "18".

FIG. 5 is a block diagram showing an embodiment of the invention set forth in claim (2), and the same parts as in FIG. 1 are given the same reference numerals to avoid redundant explanation. In the figure, 27 is the pre-movement address given to the successive address counter 6, 28 is the post-movement address, and 29 is the pre-movement address 27 and post-movement address 28 when the mobile station 10 moves beyond the zone group. This control section differs from the above-mentioned one in that it simultaneously supplies the following address counter 6 with the following.

Next, the operation will be explained. Zone group 12 shown in FIG.
The mobile station 10 moving within the radio zone 11a+ of A uses the frequency FIT as in the conventional case.

A digital signal input through communication with the base station 13a using FIR radio waves is written into one of the channel memories 2,
In the read cycle, the address is read out according to an instruction from the successive address counter 6 based on the pre-movement address 28 from the control unit 29.

At this time, the base station 13b of the adjacent zone group 12b receives the radio waves transmitted by the mobile station 10 at the frequency FIR, and the mobile station 10 receives the radio wave from the wireless zone i of the zone group 12b.
Before moving to ib, the audio encoded frame is synchronized and acquired in advance. That is, as shown in the time chart of FIG. 6, the digital signal written to the input address 22 with line salt "B' and time slot number °4" in the write mode is the same as the line salt "A" in the continuous mode. It is read out at the pre-movement address 27 of time slot number "17".

Here, the mobile station 10 is in the wireless zone 11 of the zone group 12b.
When the mobile station 10 attempts to move beyond the zone group to wireless zone llb, the digital signal written to the input address 22 is transmitted not only to the pre-movement address 27 but also to the frequency F9T assigned after the mobile station 10 moves to wireless zone llb. It is also read by the address 28 after movement of the line salt "F" and time slot number "12" corresponding to the radio waves of F9R, and the synchronization information of the audio encoded frame corresponding to the radio waves of frequencies F9T and F9R is captured in advance. be done.

Thereafter, when the mobile station 10 moves to the wireless zone 11b, reading by the pre-move address 27 is stopped, and reading is performed only by the post-move address 28, completing channel switching.

In the above embodiment, the case where the destination of the mobile station is known is explained, but the present invention is also applicable to the case where the destination is unknown. FIG. 7 is an explanatory diagram showing the structure of address information in the control section 29 in such an embodiment.

As shown in the figure, the control unit 29 has one pre-movement address 27 corresponding to each mobile station, and a plurality of post-movement addresses 2B to 28n corresponding to all surrounding wireless zones.
is available. When the mobile station moves across a group of zones and moves from one radio zone to another, the mobile station reads digital signals based on the pre-movement address 27 and each post-movement address 28 to 28n while the mobile station is in the radio zone before movement. After that, when it is determined which wireless zone the mobile station has moved to, only the post-movement address of the destination is left.
Stop reading digital signals using other post-move addresses. This makes it possible to help synchronize acquisition of voice coded frames no matter which wireless zone the mobile station moves to.

The following table shows that under such circumstances, the mobile station 10 is in the wireless zone 11a.
+-11b+-+11b: This shows the radio wave frequency and synchronization situation when moving from + to +.

〔Effect of the invention〕

As described above, according to the invention described in claim (1), a digital signal is supplied to both the pre-exchange address and the post-exchange address for a predetermined period of time prior to channel switching. With this structure, synchronization of audio encoded frames is assisted, and a time-division switching system that does not cause interruptions in voice communication during switching can be achieved.

Further, according to the invention described in claim 1 (2), while the mobile station is in the zone group before movement, the voice encoded frame is captured in the zone group to which the mobile station is moving, and the digital signal is also transmitted to the address after movement. Since the system is configured to supply audio for a certain period of time, synchronization of audio encoded frames is facilitated, and a time-division switching system that does not cause audio interruptions even when a mobile station moves across zone groups can be achieved. There is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a time division switching system according to an embodiment of the invention as claimed in claim (1), FIG. 2 is a time chart showing its operation, and FIG.
4 is a block diagram showing another embodiment of the invention described in , FIG. 4 is a time chart showing its operation, and FIG. 5 is a block diagram showing another embodiment of the invention described in claim (2).
FIG. 6 is a block diagram showing an embodiment of the invention described in , FIG. 6 is a time chart 1 showing its operation, and FIG.
FIG. 8 is a block diagram showing a conventional time-division switching method, and FIG. 9 is an explanatory diagram illustrating a time-division switching method in a mobile radio system. . 10 is a mobile station, 11 at to I I bs is a wireless zone, 12a and 12b are zone groups, I7 is an address before exchange, 18 is an address after exchange, 27 is an address before movement, 28
is the address after moving. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) In a time-division switching system that handles digital signals with long audio encoded frames and in which channel switching is performed from a pre-exchange address to a post-exchange address even during a call, for a certain period of time prior to the channel switching, the A time division switching method characterized in that the digital signal is supplied to both the pre-exchange address and the post-exchange address. (2) As a mobile station handles digital signals with long audio encoded frames and moves across a zone group formed by multiple wireless zones even during a call, movement within a zone group before movement occurs. In a time-division switching method in which channel switching is performed from a previous address to a post-move address in a destination zone group, when the mobile station is in the pre-move zone group, in the destination zone group, the mobile station is already in the pre-move zone group. A time division switching system characterized in that the radio frequency signal of the mobile station is received at the address and the audio encoded frame is captured, and the digital signal is also supplied to the post-movement address for a certain period of time.