JP2605613B2 - SOH termination circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an SDH (Synchronous
The present invention relates to an SOH (Section Over Head) termination circuit in a Digital Hierarchy (synchronous network) wireless transmission system, and more particularly to an SOH termination circuit in an intermediate relay station.

[0002]

2. Description of the Related Art An example of a conventional SOH termination circuit in an intermediate relay station is shown in FIG. The demultiplexing circuit 101 constituting the SOH terminating circuit inputs the demodulated digital signal 10 of the 2 ⁿ -modulated received signal, establishes the synchronization of the radio frame by detecting the radio frame synchronization pattern, and performs radio communication overhead (hereinafter referred to as “overhead”). A wireless OH is extracted, an overhead signal 14 is output, a wireless frame pulse (hereinafter referred to as a wireless F pulse) 11 indicating the head of the wireless frame, and a wireless OH pulse (hereinafter referred to as an OH pulse) indicating the position of the wireless OH. 12) and data 13 in n columns are output.

The first speed conversion circuit 201 removes the wireless OH in the input data 13 by the OH pulse 12 and
STM-N signal 30 which is data in MN format
To speed conversion. 8 (1) shows data 13 before speed conversion, and FIG. 8 (2) shows ST after speed conversion in the case of column n = 6.
5 shows the MN signal 30.

[0004] The STM-N terminating circuit 202 is an STM-N
The frame synchronization byte in the signal 30 is detected, the frame synchronization of STM-N is established, and the descrambling and SOH (Sect.
It performs demultiplexing / multiplexing and scramble processing of an ion over head, and outputs an STM-N signal 33. Isolated S
The OH is processed by another circuit (not shown), and multiplexing is performed again.

[0005] The second speed conversion circuit 203 performs speed conversion for adding a time slot for wireless OH to the input STM-N signal 33, and converts the OH pulse 25, wireless F pulse 26 and data 27. Output.

The multiplexing circuit 105 multiplexes an input signal 27 with an overhead signal (hereinafter referred to as an OH signal) 29 based on the OH pulse 25 and the radio F pulse 26, and outputs multiplexed data 28.

[0007]

However, in this conventional SOH termination circuit, the speed is twice converted in order to terminate the SOH in the intermediate relay station, so that the circuit configuration is complicated and expensive. With problems.

An object of the present invention is to provide an inexpensive SOH termination circuit with a simpler circuit configuration.

[0009]

In order to achieve the above object, an SOH termination circuit of the present invention divides a frame of a synchronous transmission module STM-N in a synchronous digital hierarchy into a predetermined size, and transmits a radio signal to each of the division results. A SOH termination circuit of an intermediate relay station in a ²ⁿ modulation scheme (n ≧ 2) SDH wireless transmission system that adds a communication overhead and communicates as a radio frame, and is a demodulated digital signal in which a ²ⁿ modulated received signal is demodulated. A demultiplexing unit that establishes radio frame synchronization and separates radio communication overhead from the signal, and outputs n columns of data and a signal indicating the radio frame, and passes the radio communication overhead as it is based on the signal indicating the radio frame. , N columns × m
With the row (where m ≧ n, m = p × 8; p is a positive integer) as one unit, the data of n columns is converted into data of m columns,
First column conversion means for outputting m column data together with a signal indicating the data position of redundant data in the conversion units n + 1, n + 2,..., M and the position of wireless communication overhead;
STM-N frame synchronization and descrambling required for STM-N signal processing ignoring redundant data and overhead in m-column input data from signals indicating the data position of redundant data and the position of wireless communication overhead ,
First to perform processing such as SOH separation / multiplexing and scrambling
STM-N termination means, second column conversion means for performing m-column / n-column conversion while removing redundant data from m-column data output from the STM-N termination means, and the second column Multiplexing means for performing multiplexing processing of radio communication overhead on n columns of data output from the converting means, wherein the arrangement of the STM-N frame and the radio frame is uniquely determined, and the multiplexing processing is performed. It is characterized in that synchronous transmission of data is enabled without frequency conversion for data transmission.

[0010]

According to the SOH termination circuit of the present invention, data of n columns is converted into data of m columns using n columns × m rows as one unit,
The m column data is output together with a signal indicating the data position of the redundant data in the (n + 1), n + 2,... STM-N necessary for STM-N signal processing ignoring redundant data and overhead in m columns of input data from signals
Such as frame synchronization, descrambling, etc., m-column / n-column conversion is performed while removing redundant data from m-column data, and multiplexing processing of wireless communication overhead is performed on the n-column data. This enables synchronous transmission. Therefore, there is no change in the number of rows processed per frame during the processing, so that frequency conversion for processing is not required.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the termination circuit will be described in detail. 1 to 6 show an embodiment of an SOH termination circuit according to the present invention. FIGS. 1 to 3 show a first embodiment, and FIGS. 4 to 6 show a second embodiment.

FIG. 1 is a block diagram of a first embodiment,
Separation circuit 101, first column conversion circuit 102, STM-N
It comprises a termination circuit 103, a second column conversion circuit 104, and a multiplexing circuit 105. In the first embodiment, n columns and m rows of the input signal 10 are respectively set to n = 6 (for example, 2 ⁶ = 64 modulation) and m for the purpose of clarifying the explanation.
= 8.

The demultiplexing circuit 101 receives the demodulated digital signal 10 of the ^26- modulated received signal, establishes the synchronization of the radio frame by detecting the radio frame synchronization pattern, extracts the radio OH, and then starts the radio frame. , An OH pulse 12 indicating the position of the wireless OH, and data 13 in six columns.

FIG. 2 shows an OH pulse 12 and data 13 which are output signals of the demultiplexing circuit 101. In this figure, O _ij is the wireless communication overhead (wireless OH),
A _kl indicates an STM-N signal. However, the symbol
i, j, k, l are simply integers indicating the order. Also, STM-
Since the arrangement of the N frame and the radio frame is uniquely determined, the beginning of the byte of the STM-N signal (a ₁₁ in the figure) is arranged in the row of the time slot next to the radio OH.

The first column conversion circuit 102 outputs the OH pulse 1
2, the wireless OH in the input data 13 is passed as it is, and the next n × m (= 6 × 8) data (a ₁₁ ) of the wireless OH
To a ₆₈ ) as one unit, and perform 6-column / 8-column conversion. However,
No frequency conversion is performed, and the 7th and 8th rows for each conversion unit become redundant data, and this redundant data is output to data 17. Also, together with the data 17, the wireless F pulse 15, O
A redundant pulse 18 indicating the position of the redundant data in the H pulse 16 and the data 17 is output.

FIG. 3 shows an OH pulse 16, a redundant pulse 18, and data 17 which are output signals of the first column conversion circuit 102. The STM-N termination circuit 103
From the H pulse 16 and the redundant pulse 18, the wireless OH and redundant data are ignored, STM-N frame synchronization is established, descrambling, SOH separation / multiplexing and scrambling are performed, and data 23 is output. Data 23
Output the OH pulse 22 and the wireless F pulse 21 corresponding to.

The second column conversion circuit 104 outputs the OH pulse 2
2, the wireless OH in the input data 23 is passed as it is (two columns are deleted), and the next m × n (= 8)
× 6) data (a _{11 to} a ₆₈ ) as one unit and 8 columns /
The inverse transformation of six columns is performed, and data 27 and data 2 of six columns are obtained.
7 and outputs an OH pulse 26 and a wireless F pulse 25 corresponding to. However, no frequency conversion is performed.

The multiplexing circuit 105 controls the wireless O in the input data 27 based on the OH pulse 26 and the wireless F pulse 25.
The OH signal 29 is multiplexed at the H position, and the multiplexed data 28
Is output. Although the above description has been made for n = 6 and m = 8, other combinations can be similarly configured.

FIG. 4 is a block diagram of the second embodiment.
This embodiment shows an example of the configuration of an SOH termination circuit for performing synchronous transmission of data of the 2 ⁿ modulation system when the arrangement of the STM-N frame and the radio frame is not uniquely determined. . Also in the present embodiment, a combination of input signal columns n = 6 and rows m = 8 will be described. Separation circuit 10
The operation of No. 1 is the same as that of the first embodiment.

FIG. 5 shows a part of the output signal of the demultiplexing circuit 101. Since the arrangement of the STM-N frame and the radio frame is not uniquely determined, the data a _{23 to} a _{38 are shown.} Next, an example is shown in which O _{11 to} O ₁₆ of the wireless OH are arranged.

The third column conversion circuit 106 outputs the OH pulse 1
From 2, ignoring the wireless OH in the input data 13,
The frame synchronization byte of STM-N is detected, and STM-N
STM of 6 × 8 data while passing the wireless OH through 6-column / 8-column conversion in order from the top of the frame (a _{11 in} this example)
-Performs in units of N frames and outputs data 47 after column conversion. At the same time, the wireless F pulse 45 corresponding to the data 47,
An OH pulse 46, a redundant pulse 48, and an STM-N frame pulse (hereinafter, simply referred to as an F pulse) 49 indicating the head of the STM-N frame are output.

FIG. 6 shows a part of the output signal of the third column conversion circuit 106. STM-N termination circuit 10
7 performs descrambling, demultiplexing / multiplexing of SOH and scrambling according to the F pulse 49 ignoring the wireless OH and redundant data in the input data 47 from the OH pulse 46 and the redundant pulse 48, and outputs data 63. Further, it outputs a wireless F pulse 61, an OH pulse 62, a redundant pulse 64, and an F pulse 65 corresponding to the data 63.

The fourth column conversion circuit 108 outputs the OH pulse 6
2, the wireless OH in the input data 63 is passed as it is, two columns of redundant data are deleted, and column conversion of eight columns / 6 columns is performed. This conversion is performed for each 8 × 6 data STM-N frame unit by the F pulse 65, and the wireless F pulse 25 and the OH pulse 26 are output together with the data 26. The operation of the multiplexing circuit 105 is the same as that of the first embodiment, and the description is omitted here.

As described above, according to the present invention, the overhead for radio communication is separated, and the overhead is ignored from the signal indicating the position of the radio communication overhead.
STM-N frame synchronization required for M-N signal processing,
Processing such as descrambling, SOH separation / multiplexing, and scrambling is performed. According to this processing procedure, the STM-N SO
There is no need to perform frequency conversion to perform the H termination processing, and the circuit configuration of the STM-N termination circuit is simplified, resulting in an effect of lower cost.

Although the above embodiment is an example of a preferred embodiment of the present invention, the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.

[0026]

As is clear from the above description, the SOH termination circuit of the present invention converts the data in frame units into n columns / m columns (n ≦ m) and converts the data into n + 1, n + 2,.
A signal indicating this position is provided with the m-th row as redundant data,
Since processing such as STM-N frame synchronization and descrambling required for STM-N signal processing is performed ignoring redundant data and overhead, the number of rows processed per frame does not change in these processing steps. Does not require frequency conversion for Therefore, the circuit configuration is simplified, and the processing circuit can be easily configured at lower cost.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a first embodiment of an SOH termination circuit according to the present invention.

FIG. 2 is a diagram conceptually showing a configuration example of data input to a first column conversion processing circuit of FIG. 1 and a timing relationship between wireless OH pulses;

3 is a diagram conceptually showing a configuration example of converted data output from a first column conversion processing circuit in FIG. 1 and a timing relationship between a wireless OH pulse and a redundant pulse.

FIG. 4 is a circuit configuration block diagram showing a second embodiment of the SOH termination circuit of the present invention.

FIG. 5 is a diagram conceptually showing a configuration example of data input to a third column conversion processing circuit in FIG. 4 and a timing relationship between wireless OH pulses;

6 is a diagram conceptually showing a configuration example of converted data output from a third column conversion processing circuit in FIG. 4 and a timing relationship between a wireless OH pulse and a redundant pulse.

FIG. 7 is a block diagram showing a circuit configuration example of a conventional SOH termination circuit.

FIG. 8 is a diagram showing an example of a data configuration of a conventional SOH termination circuit before and after speed conversion.

[Explanation of symbols]

 Reference Signs List 10 demodulated digital signal 11 wireless F pulse 12, 16, 22, 26 OH pulse 13, 17, 23, 27 data 14 overhead signal 15, 21, 25 wireless F pulse 18 redundant pulse 28 multiplexed data 29 OH signal 101 separation circuit Reference Signs List 102 first column conversion circuit 103 STM-N termination circuit 104 second column conversion circuit 105 multiplexing circuit

Claims (1)

(57) [Claims] 1. A 2 ⁿ modulation system (n) in which a frame of a synchronous transmission module STM-N in a synchronous digital hierarchy is divided into a predetermined size, and a radio communication overhead is added to each of the division results to communicate as a radio frame. ≧ 2) in the SOH termination circuit of the intermediate relay station in the SDH wireless transmission system, wherein the SOH termination circuit establishes radio frame synchronization and radio communication overhead from the demodulated digital signal obtained by demodulating the 2 ⁿ modulated received signal. And demultiplexing means for outputting data of n columns and a signal indicating a radio frame, and passing the radio communication overhead as it is based on the signal indicating the radio frame, and n columns × m rows (where m ≧ n, m
= P × 8; p is a positive integer), and the data in the n-th column is converted into data in the m-th column without conversion of the clock frequency, and the conversion units n + 1, n + 2,. First column conversion means for outputting m-column data together with a signal indicating the data position of the redundant data and the position of the wireless communication overhead; and a signal indicating the data position of the redundant data and the position of the wireless communication overhead. , Ignoring the redundant data and the overhead in the m columns of input data, and performs processing such as STM-N frame synchronization, descrambling, SOH separation / multiplexing, and scrambling required for STM-N signal processing. First STM-N terminating means; second column converting means for performing m-column / n-column conversion while removing redundant data from m-column data output from the STM-N terminating means; Multiplexing means for performing multiplexing processing of radio communication overhead on n columns of data output from the second column conversion means, wherein the arrangement of the STM-N frame and the radio frame is An SOH termination circuit, which is uniquely determined and enables synchronous transmission of data.