JP2000106537A - Communication channel multiplexer between satellite base station and portable satellite terminal station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of communication channels between a portable satellite terminal and a satellite base station installed on emergency by utilizing the band compression technology. SOLUTION: The communication channels are multiplexed by dividing digital channels between a portable satellite terminal station 2 and a satellite base station 3 to configure a plurality of sub channels, and superimposing voice data subject to band compression on the sub channels by a band compander according to a time slot number of the sub channels stored in a time slot memory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system in which a communication channel between a satellite base station and a portable satellite terminal station is divided into a plurality of sub-channels via a communication satellite, and the degree of multiplexing is increased using a voice band compression device. The present invention relates to a channel multiplexing device.

[0002]

2. Description of the Related Art Conventionally, portable satellite terminal stations have been developed for the purpose of bringing to the stricken area in the event of a disaster or the like and securing at least one channel communication path to the stricken area. In general, the communication channel has one channel.

[0003]

However, in the above-mentioned conventional system, since there is only one communication channel, there is often confusion due to shortage of channels.

[0004] It is an object of the present invention to increase the number of communication channels between a portable satellite terminal station and a satellite base station while allowing a degree of freedom in connection, even if the voice quality is slightly degraded.

[0005]

In order to solve the above-mentioned problems, the invention according to the first aspect of the present invention relates to a communication between a satellite base station and a portable satellite terminal station connected by a time division digital channel. By further dividing the digital channel between the base station and the portable satellite terminal station in time, a plurality of sub-channels are formed to multiplex the channels, and the satellite base station and the portable satellite terminal station have A bandwidth compression / expansion device corresponding to a plurality of terminal devices or communication lines, and a transmission buffer for temporarily storing compressed audio data;
By arranging a reception buffer and a time slot memory for storing the time slot number of the sub-channel, and writing the time slot number of the sub-channel in the time slot memory under the control of the control unit,
A connection between the plurality of terminal devices or communication lines and the plurality of sub-channels is provided with a time-division switching function.

According to the present invention, the number of communication channels between a satellite base station and a portable satellite terminal station can be increased, and the satellite base station and the portable satellite terminal station can have a time-division switching function. Free connection becomes possible.

[0007]

FIG. 1 shows a system configuration according to an embodiment of the present invention.

In FIG. 1, 1 is a communication satellite, 2 is a portable satellite terminal, and the portable satellite terminal 2 has a telephone 4-
1. Terminal devices such as a headset 4-2 and a cordless telephone 4-3 are connected.

Reference numeral 206 denotes a band compression / decompression unit of the portable satellite terminal device, and reference numeral 207 denotes a multiplexing function unit.

Reference numeral 3 denotes a satellite base station, in addition to the telephone 4-1.
A public communication network 5 and a private branch exchange (PBX) 6 are also connected.

Reference numeral 301 denotes a band compression / decompression unit of the satellite base station, and 302 denotes a multiplexing function unit.

In the embodiment shown in FIG. 1, the number of portable satellite terminal stations 2 is two, but this number can be changed as required.

The satellite base station 3, communication satellite 1, and portable satellite terminal station 2 are connected via the communication satellite 1 by time division multiplex access.

In the present embodiment, it is assumed that the space between the portable satellite terminal station 2 and the satellite base station 3 is composed of one 64 Kbps voice channel.

[0015] Therefore, the voice is transmitted at 16 Kb including the control information.
If it can be compressed to less than 1 ps, a 64 Kbps channel can be
It can be used as 4 subchannels of 6 Kbps.

The outline of the operation will now be described on the assumption that the portable satellite terminal station 2 on the upper side of the drawing is called from the public communication network 5.

When there is an incoming call from the public communication network 5 to the satellite base station 3, it is connected to the band compression / decompression unit 301 through an interface circuit (not shown).

There are several types of band compression schemes used in wireless systems. Here, vector-sum driven linear prediction coding (V
ector Sum Excited Linear
Predictive Coding) (hereinafter referred to as VSE
LP).

Although the compression ratio of VSELP is variable, it is compressed to 9.6 Kbps and 16 kb including control information.
The explanation proceeds assuming that the value is within ps.

64 kbp in band compression / decompression section 301
s of the public network 5 is 1 for the uplink.
Compressed to 6Kbps VSELP voice and 64Kbps for 16Kbps VSELP voice for downlink
Decompress to s PCM audio or analog audio.

In this embodiment, since the uplink and the downlink are paired, the selection of the sub-channel determines the uplink and the downlink.

Since the audio signal that has passed through the band compression / expansion unit 301 is compressed to 16 Kbps, the 64 Kbps channel can be divided into four and carried on 16 Kbps subchannels.

In the multiplexing function unit 302, the 16 Kbps
To the portable satellite terminal station 2 on the upper side of the drawing.
An unoccupied sub-channel is selected and placed on the sub-channel.

Thus, the satellite base station 3 is connected to the portable satellite terminal station 2 on the upper side of the figure.

In the portable satellite terminal station 2, the connection to the terminal device changes depending on whether a dial number is sent from the base station 3, an additional number is sent, or nothing is sent.

When the dial number or the additional number is sent, the terminal device to be connected is specified, so that the multiplexing function unit 207 specifies the band corresponding to the specified terminal device, for example, the telephone set 4-1. Connect to the compression / expansion unit of the compression / expansion unit 206, and in the downlink, a VS of 16 Kbps
The ELP is converted to 64 kbps PCM voice or analog voice, and the 64 kbps PCM voice or analog voice is converted to 16 kbps VSELP signal in the uplink.

Thus, the called terminal device 4-1 can talk with the other party of the public communication network 5.

When neither the dial nor the additional number can be received, the multiplexing function unit 207 causes the vacant terminal device 4-1 to operate.
Select one of 4-3 from and connect.

In this case as well, if a number is assigned to each terminal device, a call is transferred between the terminal devices under the control of the multiplexing function unit 207 of the portable satellite terminal station 2 after connection to a certain terminal device. Can be.

FIG. 2 is a block diagram showing the internal configuration of the portable satellite terminal station 2.

External interface unit (hereinafter referred to as external I / F)
The unit 203 includes an interface 204 with the telephone 4-1 and the cordless telephone 4-3, and an interface 205 with the headset.

It is assumed that the interface with the cordless telephone 4-3 is a telephone interface, and that the cordless telephone is connected between the telephone and the handset.

Telephone interface (TELI / F) 2
04 and headset interface (HDSI /
F) 205 has a function of converting analog voice into waveform-coded voice of 64 Kbps,
01 is passed in the form of digital voice to the band compression / decompression unit 206.

The band compression / expansion unit 206 includes a plurality of compression / expansion units 218, and each of the compression / expansion units 218
/ F section 203 corresponds to various interfaces 204 and 205.

The baseband unit 201 comprises the band compression / expansion unit 206 and the multiplexing function unit 207. The multiplexing function unit 207 includes a reception buffer 208, a transmission buffer 209, and a time slot memory (corresponding to the compression / expansion unit 218). Hereinafter, this is referred to as a TS memory) 210.

The TS memory 210 mentioned here has a capacity of 64 Kb.
not the time slot in the frame structure of ps,
This is a TS memory for storing time slots of sub-channels described later.

Numeral 211 denotes a modulation unit, which includes four transmission buffers 2
09 for each of the four transmission buffers.
A digital signal of Kbps is put on the modulation wave. Modulation unit 2
11 is provided corresponding to the number of 64 Kbps channels handled by the satellite terminal station 2. A transmission frequency converter 212 converts the modulated wave into a frequency to be sent to the communication satellite 1.
This transmission frequency conversion section 212 is also 1
One is provided.

Reference numeral 213 denotes an antenna unit which transmits the radio wave of the transmission frequency converted by the transmission frequency conversion unit 212 to the communication satellite 1. This antenna section 213 is common to all transmission frequency conversion sections 212 and is also used for reception.

A receiving frequency converter 215 converts a radio wave received from the communication satellite 1 into a frequency of a modulated wave, and is paired with the transmitting frequency converter 212.

A demodulation unit 214 extracts a digital signal from the modulated wave. The demodulation unit 214 is paired with the modulation unit 211.

Reference numeral 202 denotes a control unit for controlling the entire terminal station 2, which also sets a time slot of a sub-channel in the TS memory 210 described above.

An operation panel unit 216 instructs the control unit 202 to perform various settings such as multiplex setting.

Reference numeral 217 denotes a power supply unit, which is an AC power supply, a DC power supply,
Compatible with any of the batteries.

The configuration of the satellite base station 3 is basically the same as that of the portable satellite terminal station 2, and only the number of channels handled is increased.

The operation of portable satellite terminal station 2 when a call is transmitted from telephone 4-1 will be briefly described.

When the handset is picked up by the telephone 4-1, the telephone interface (TELI / F) 204 is activated, and the dial tone is returned. Control unit 2 when caller dials
02 receives this and determines which sub-channel to select.

When the sub-channel is determined, the TS memory 21 of the multiplexing function unit 207 corresponding to the calling telephone 4-1
The time slot number of the selected sub-channel is written in 0.

In the satellite base station 3, the same setting for an incoming call is made based on the sub-channel number and dial number used from the control unit 202 of the portable satellite terminal station 2.

As a result, the connection of the satellite portion is completed, and the transmission from the telephone 4-1 of the terminal station 2 is digitized by the telephone interface (TELI / F) 204,
The data is compressed to, for example, 16 Kbps by the ELP compression / decompression device 218 and temporarily stored in the transmission buffer 209. When the time slot of the sub-channel stored in the TS memory 210 comes, the compressed audio data is transmitted from the transmission buffer 209 to the modulating unit 211 and modulated together with the audio data of the other sub-channels as a digital bit string of 64 Kbps. .

The modulated wave is raised to the frequency to be transmitted to the communication satellite 1 by the transmission frequency converter 212 and
3 to the communication satellite 1.

On the other hand, a radio wave received from the communication satellite 1, that is, a downlink radio wave is received by the antenna unit 213, and is lowered to the frequency of the modulated wave by the reception frequency conversion unit 215.
The signal is demodulated by the demodulation unit 214 and returned to a digital bit string of 64 Kbps.

From the bit string, only the bits of the time slot of the sub-channel stored in the TS memory are extracted and temporarily stored in the reception buffer 208.

The data stored in the reception buffer 208 is sent to the compression / decompression device 218 at a speed of 16 Kbps and transmitted to the
bps waveform-encoded speech, and the external I / F 20
3 is converted into an analog voice by the telephone interface (TELI / F) 204 and sent to the telephone 4-1.

Since a similar connection is made on the satellite base station 3 side, a call with the called party becomes possible.

As described above, the terminal devices 4-1 to 4-1-4
Since the correspondence between -3 and the sub-channel is determined by the time slot number of the sub-channel stored in the TS memory 210, the connection can be freely changed by the control unit 202 rewriting the contents of the TS memory.

In other words, the multiplexing function unit 207 has a time division switching connection function, and can freely connect between the sub-channel and the terminal device.

If the connection destination on the satellite base station 3 side is a digital line as in the public communication network 5, analog conversion is not performed in the external I / F unit 203 on the satellite base station 3 side, and the connection is made digitally. .

In the above description, the case where the communication satellite 1 and the portable satellite terminal station 2 are 64 Kbps 1 channel and are connected to each other by converting them into 4 sub-channels is used.
, A certain 64 Kbps channel is sub-channeled, and the others are not sub-channeled.
It can be used as a 4 Kbps channel, and these can be set on the operation panel section.

An example of a method of converting a 64 Kbps channel into a plurality of sub-channels will be described with reference to FIGS.

FIG. 3 shows a frame and bit configuration when digital multiplexing is performed on a 64 Kbps channel.
00 frames / sec, in other words, the length of one frame is 1
It is composed of 25 μs.

Each frame has n time slots (T
S) and the same numbered time slot (TS)
Constitute one channel.

The lower part of FIG. 3 shows the frame 1 and the time slot (TS) 1 further developed in bit units.
It consists of 8 bits.

Therefore, 8 bits × 8000 frames = 6
4000, which is a configuration in which 64 Kbps channels are multiplexed into n channels.

FIG. 4 (a) divides 8 bits of one time slot (TS) in FIG.
ch) Four. Since each sub-channel (sch) has 2 bits per frame, in frame 1 bits 1 and 2 of the sub-channel (sch), in frame 2 bits 3 and 4 of the sub-channel (sch),
In frame 4 (not shown), bits 7 and 8 of the subchannel (sch) are obtained, which means that one time slot (TS) is divided into four subchannels (sch).

Accordingly, the time slot number (64 Kbps) of the subchannel (sch) is stored in the TS memory 210 of FIG.
By storing the time slot (TS) number and the bit number in the time slot (TS) in the channel, four channels of 16 Kbps can be identified.

FIG. 4B shows one time slot (T
S) is a bit configuration diagram in the case of dividing into two, and is 64 Kbps.
Channel can be divided into two 32 Kbps channels.

Although not shown in the figure, if the eight bits of one time slot (TS) are divided into eight sub-channels (sch), it is possible to divide the 64 Kbps channel into eight 8 Kbps channels. .

Since the division into the sub-channels (sch) is determined by the contents to be written in the TS memory 210 in FIG. 2, any of the n channels can be implemented.
The division into sub-channels (sch) can also be freely changed.

Therefore, the multiplex setting is performed by the operation panel section 21.
6 can be easily performed by instructing the control unit 202.

In the satellite base station 3, the multiplicity can be freely changed depending on the satellite terminal station 2 of the communication partner, so that different multiplicity can be taken even in the same satellite terminal station 2.

Since the change of the multiplicity can be performed by rewriting the TS memory by the control unit 202, the control unit 2 of the portable satellite terminal station 2 is operated from the operation panel unit of the satellite base station 3 via the control unit.
It is also possible to send an instruction to 02 and change the setting by remote control.

FIG. 5 is a flowchart of the multiplex setting. First, in step S1, it is determined whether or not to make settings in the operation panel setting mode.

In the operation panel setting mode, the operation panel section 216 and the control section 202 are set to the operation panel setting mode in step S2. Then, it is determined in step S4 whether the mode is the multiplexing mode. If the mode is the multiplexing mode, the apparatus default mode is set according to the channel (step S8), and the multiplexing is individually set (step S4).
7), the detailed setting mode is set (step S6).

If the mode is not the multiplexing mode in step S4, multiplexing is not performed (step S9).

If the operation panel setting mode is not set in step S1, the remote control mode from the satellite base station is set (step S3).

Then, it is determined whether or not the mode is the multiplexing mode (step S5). If the mode is the multiplexing mode, steps S6 to S8 are set as in the case of the operation panel setting mode.

If the mode is not the multiplexing mode in step S5, no multiplexing is performed (step S9).

[0078]

According to the present invention, 64 Kbps voice can be converted to 32 Kbps, 16 Kbps, or 8 Kbps.
By using VSELP voice band compression technology to compress such voices and multiplex them on a 64 Kbps digital channel, the effect of multiplexing the communication satellite channels between a few satellite base stations and portable satellite terminal stations can be achieved. Have.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram according to an embodiment of the present invention.

FIG. 2 is a block diagram of a portable satellite terminal station.

FIG. 3 is a diagram illustrating a frame configuration and a bit configuration of a 64 Kbps digital channel.

FIG. 4 shows 16 Kb for a 64 Kbps digital channel.
It is a bit structure figure which carries ps and audio of 32Kbps.

FIG. 5 is a flowchart for setting multiplexing of a portable satellite terminal station.

[Explanation of symbols]

 Reference Signs List 1 communication satellite 2 portable satellite terminal station 201 baseband section 202 control section 203 external I / F section 206 band compression / decompression section 207 multiplexing function section 208 reception buffer 209 transmission buffer 210 TS memory 211 modulation section 212 transmission frequency conversion section 213 Antenna unit 214 Demodulation unit 215 Reception frequency conversion unit 218 Band compression / expansion unit 3 Satellite base station 4-1 to 4.3 terminal equipment 5 Public communication network 6 Private branch exchange (PBX)

Claims (1)

[Claims] 1. In a communication between a satellite base station and a portable satellite terminal station connected by a time division digital channel, a digital channel between the satellite base station and the portable satellite terminal station is further divided in time. By configuring a plurality of sub-channels and multiplexing channels, the satellite base station and the portable satellite terminal station have a band compressor / decompressor corresponding to a plurality of terminal devices or communication lines,
A transmission buffer for temporarily storing compressed audio data, a reception buffer, and a time slot memory for storing a time slot number of the sub-channel; and a time slot number of the sub-channel in the time slot memory under the control of a control unit. , The connection between the plurality of terminal devices or communication lines and the plurality of sub-channels has a time-division switching function, communication between the satellite base station and the portable satellite terminal station. Channel multiplexer.