JPH05167632A - Transmission system - Google Patents

Abstract

PURPOSE:To reduce a noise level of a frequency band of an incoming signal and to send the incoming signal simultaneously from two or more different blocks by allocating the frequency band of the incoming signal. CONSTITUTION:A frequency band of an incoming signal is divided into (n) sets of blocks and a specific frequency band is assigned to each block. An incoming signal from a terminal equipment T1a with a limited band by a frequency selector B1 is sent through branching devices D1, D0 in the 2-way communication among terminal equipments T1a-T2b, converted into an outgoing signal of other band by a frequency converter C in a center block and the result is sent to a receiver side via the devices D2, D0. However, the signal cannot pass through the device other than the frequency selection device B2 because the frequency band differs, but passes through the selector B2 having the same frequency band and is sent to the equipment T2b, in the terminal block 2. Simultaneously, the incoming signal from the equipment T2b is sent for the limited band only by the selector B2 through the devices D2, D0, converted into an outgoing signal of other band by the frequency converter C and passes through the frequency selector B1 and is sent to the device T1a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of reducing a noise level in a frequency band of an upstream signal in signal transmission (unidirectional or bidirectional) in a system having a plurality of terminals.

[0002]

2. Description of the Related Art In recent years, as one of the techniques for reducing the noise level on a transmission line, there is a transmission line opening / closing control by an upstream signal transmission branch line switch (hereinafter referred to as BGC).

The BGC will be described below with reference to the drawings. FIG. 5 shows a transmission system using BGC, where M is a center, L is a transmission line, and A ₁ , A ₂ , ..., _An are BGC.
, N is a block composed of a plurality of terminals, T _1a , T _1b and T _1c are terminals of block 1, and T _2a , T _2b and T _2c are Terminals of block 2, T _3a , T _3b and T _3c are terminals of block 3, D ₀ ,
D ₁ , D ₂ , ... D _n indicate branching devices.

Here, the terminal device (T _1a ,
When transmitting an upstream signal from T _1b , T _1c ), only the transmission path switches of A ₁ are turned on, and the transmission path switches (A ₂ , ..., _An ) other than A ₁ are turned off. maintain. By this operation, only noise from the block 1 exists in the upstream signal band on the transmission line L, and the noise level can be reduced. Similarly, block 2, ..., Block n
When transmitting a signal from the terminal device to the center, respectively A _2, · · ·, to open and close a channel switch of A _n.

[0005]

In the above system, the upstream signals from the terminals in any block can be transmitted, but the upstream signals from two or more different blocks cannot be transmitted at the same time.

An object of the present invention is to provide a transmission system capable of reducing the noise level in the frequency band of an upstream signal and transmitting the upstream signal simultaneously from two or more different blocks.

[0007]

In order to achieve the above-mentioned object, the present invention has a frequency selection device for each block constituted by a plurality of terminal units in the frequency band of an upstream signal,
It is divided into n bands, and the frequency band of the upstream signal is limited for each block.

[0008]

According to the present invention, the noise level in the frequency band of the upstream signal in the transmission line is determined by the block 1 according to the above configuration.
It is reduced because there is only one. Further, since all the divided blocks are in the operating state, it is possible to transmit the uplink signal from the terminal in two or more different blocks.

[0009]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, K is a center block, M is a center, C is a frequency converter, L is a transmission line, and B ₁ , B ₂ , ...
.., B _n are frequency selection devices, 1, 2, ..., N are blocks, T _1a , T _1b , and T _1c are block 1 terminals, T
_2a , T _2b and T _2c are terminals of the block 2, T _3a , T _3b and T
_3c is a terminal device of block 3, D ₀ , D ₁ , D ₂ , ... D _n ,
D _m indicates a branching device.

Here, the frequency selecting devices B ₁ , B ₂ , ...
, B _n will be described with reference to FIGS. 3 and 4. 3 shows a frequency band of an upstream signal, FIG. 4 shows a state where the band of FIG. 3 is divided into N bands, the band by B ₁ is f _{1a to} f _1b , the band by B ₂ is f _{2a to} f _2b , The band of B _n is f _{na to} f _nb .

A transmission system including the above components
The relationship and operation of each component will be described. To aim
The operation is performed between terminals between different blocks and between terminals.
Bidirectional communication between the terminal and the center. T_1a~ T_2b
Consider two-way communication between. T _1aThe upstream signal from is B₁To
More limited bandwidth (f_1a~ F_1b) Only D₁, D₀Through
Sent by the frequency converter C in the center block.
Bandwidth (f_2a~ F_2b) Downstream signal, D₀，
D₂It is transmitted to the receiving side via₂Except frequency
Since the bands are different, they cannot pass and the same frequency band (f_2a
~ F_2b) With frequency selection device B₂Pass through the terminal
For example T in lock 2_2bTransmitted to. At the same time, T_2b
The upstream signal from is B₂Band (f_2a~
f_2b) Only D₂, D₀In the center block
Frequency converter C of the band (f_1a~ F_1b) Downlink signal
Converted to D₀, D₁Through the same band (f_1a~ F_1b)of
Frequency selection device B₁Pass through the terminal block 1
Speaking of T_1aIs transmitted to and enables two-way communication. As well
To T_1aIn two-way communication between_1aUpstream signal from
Is B₁Due to the limited band D₁, D₀Transmitted through
The frequency converter C in the center block
Converted to D_mTo M. At the same time, M
These upstream signals are D_mTransmitted through the center block
Is converted to a downlink signal by a frequency converter C in the₀，
D₁Through T_1aIs transmitted to and enables two-way communication.

Further, the above-mentioned first embodiment can be applied to any modulated signal regardless of whether it is voice or data.

As described above, according to the present embodiment, by dividing the frequency band of the upstream signal and having the frequency converter in the center block, different block terminals-terminals, and terminal- Two-way communication between centers becomes possible.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, L is a transmission line, B ₁ , B ₂ , ...
.., B _n are frequency selection devices, 1, 2, ..., N are terminal blocks, T _1a , T _1b , T _1c are terminals in the terminal block 1, T _2a , T _2b , T _2c is the terminal of block 2,
T _3a , T _3b and T _3c are terminals of block 3, D ₀ , D ₁ and D
₂ , ... D _n are branching devices. The above is the same as the configuration of FIG. What is different from FIG. 1 is that a center M ₁ having a plurality of transceivers (R ₁ , R ₂ , ... R _n ) is directly connected to the transmission line instead of the center block.

With respect to the transmission system including the above-mentioned constituent elements, the relation and operation of the constituent elements will be described below.
First, in the bidirectional communication between T _{1a and} M ₁ , the upstream signal from T _1a has only the band (f _{1a to} f _2b ) limited by B _{1 and} D ₁ ,
The signal is transmitted via D ₀ to the transceiver R ₁ having the same band (f _{1a to} f _1b ) in the center M ₁ . Further, the downlink signal from the center M ₁ undergoes a D _0, D ₁ from the transceiver R ₁ in M _1,
Transmitted to T _1a . In this two-way communication, since all blocks in the transmission system according to the second embodiment are always in the operating state, a plurality of communication can be performed simultaneously between the terminals in all the blocks and the center M ₁ .

As described above, according to this embodiment, the frequency band of the upstream signal is divided and m transceivers (R ₁ , R ₂ , ..., R _m ) are provided in the center. Due to
Multiple bidirectional communication is possible between the terminal and the center.

Needless to say, in the second embodiment, as in the first embodiment, any symbol can be used regardless of whether it is voice or data, as long as it is a modulated symbol.

[0020]

As is apparent from the above description of the embodiments, the present invention reduces the noise level in the upstream signal band by dividing the frequency band of the upstream signal, and the terminals in a plurality of different blocks. It is possible to realize an excellent transmission system capable of simultaneously transmitting upstream signals from the devices.

[Brief description of drawings]

FIG. 1 is a block diagram of a bidirectional communication system according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a system for bidirectional communication according to the second embodiment.

FIG. 3 is a frequency band diagram of upstream signals.

FIG. 4 is a frequency band diagram when the frequency region is divided into n pieces.

FIG. 5 is a block diagram of a conventional transmission system using a transmission branch switch.

[Explanation of symbols]

M center B ₁ , B ₂ , ..., B _n frequency selection device 1, 2, ..., n Terminal block T _1a , T _1b , T _1c Block 1 terminal T _2a , T _2b , T _2c Terminal of Block 2 T _na , T _nb , T _nc Terminal of Block n

Claims (5)

[Claims] 1. In RF communication between a plurality of terminals and a sector, the plurality of terminals are grouped into n blocks from block 1 to block n, and a frequency band of an upstream signal from the terminal to the sector is set in each block. transmission system in (block 1, block 2, ..., block n) respectively, and by assigning a particular frequency band _{(f 1a ~f 1b, f 2a} ~f 2b ···, f na ~f nb) a. 2. A signal of n frequency bands is converted into a downlink symbol band in a center block and is transmitted to each terminal and center, so that between terminals and terminals, and between terminals.
The transmission system according to claim 1, wherein bidirectional communication between centers is performed. 3. The transmission system according to claim 1, wherein the transmission system has m receivers for demodulating signals in n frequency bands at a center, respectively, for communication. 4. The transmission system according to claim 3, wherein the center has m transmitters for modulating each and bidirectional communication is performed. 5. The transmission system according to claim 1, wherein the transmission system transmits by a voice signal.