JPH0253339A - Pseudo-synchronization preventing system - Google Patents

Abstract

PURPOSE:To establish correct frame synchronization by deciding that a main signal is in a frame synchronizing condition when a first pattern signal to be extracted in a receiving side is coincident with a second pattern signal to be generated in the receiving side, deciding that the main signal is out of the frame synchronizing condition when the pattern signals are discordant, and executing synchronization feedback operation. CONSTITUTION:In a multiplexing means 30 in a transmitting side, the first pattern signal to be generated from a first pseudo-synchronization preventing pattern generating means 100 is inserted to stuff information for the main signal and transmitted. A signal reception processing means 50 in the receiving side detects the stuff information from the received signal and destuff information are prepared and sent. A second pseudo-synchronization preventing pattern generating means 200 is accessed by the destuff information and the second pattern signal is sent to a pseudo-synchronization deciding means 90. In the pseudo-synchronization deciding means 90, the exact position of a frame synchronizing pattern is grasped by comparing the first pattern signal, which is extracted from the received signal, and the second pattern signal and deciding the presence and absence of the coincidence. Thus, exact signal restoring can be executed.

Description

[Detailed Description of the Invention] [Summary] Regarding a pseudo-synchronization prevention method for frame synchronization of main signals in digital radio equipment, the present invention attempts to establish correct frame synchronization using pseudo-synchronization determination information inserted into staff information. The purpose of this is to provide a pseudo synchronization prevention method, and the transmitting side and the receiving side are provided with first/second pseudo synchronization prevention pattern generating means for generating first/second patterns serving as pseudo synchronization patterns, and If the first pattern signal extracted on the receiving side matches the second pattern signal generated on the receiving side, it is determined that the main signal is in frame synchronization, and if they do not match, it is determined that the main signal is out of frame synchronization. The configuration is configured so that it is determined that there is such a synchronization, and a synchronization recovery operation is performed.

[Industrial application field]

The present invention relates to a method for preventing false synchronization of main signal frame synchronization in a digital radio device.

In digital transmission systems, when multiplexing and transmitting multiple signals at lower ranks of the digital hierarchy, there are two forms: stuff synchronous multiplexing and frequency synchronous multiplexing.
Stuffed synchronous multiplexing is used when the clock frequencies of low-speed digital signals do not completely match.

Frame synchronization of the multiplexed signal as described above is performed by receiving frame synchronization pulses forming a predetermined pattern.

However, in digital wireless devices, pseudo-synchronization may occur using a frame synchronization pattern that includes pulses other than frame synchronization pulses, and reliably preventing such pseudo-synchronization is the key to accurately and reliably transmitting and receiving the main signal. It leads to this.

[Conventional technology]

FIG. 3 is a block diagram illustrating a conventional example, and FIG. 4 is a diagram illustrating a frame format of a multiplexed signal.

This example shows an outline of the configuration of the transmitting side and receiving side of a digital radio device, with the left side of FIG. 3 showing the transmitting side and the right side showing the receiving side.

The configuration of the transmitting side of the digital wireless device includes a speed converter 1 that converts the signal speed by retiming a plurality of input signal speeds using the clock timing of a predetermined speed; and a speed converter 1 that converts the signal speed. A signal processing circuit 2 that performs various processing to insert the content of the clock pulse to be inserted or removed as stuff information and transmit it as a digital radio signal, and a multiplexing circuit that multiplexes a plurality of transmission signals processed by the signal processing circuit 2. (hereinafter referred to as MAX section) 3, and a transmitting antenna A for transmitting digital radio signals from the transmitting side at a predetermined radio frequency.
, NT1.

On the other hand, the configuration for receiving the digital radio signal transmitted from the transmitting antenna ANTI by the receiving antenna ANT2 and processing this received signal includes performing various processes for decoding a plurality of input signals input to the receiving side. A signal processing circuit 5, a frame synchronization unit 6 that performs frame synchronization of the signal received by the reception antenna ANT2, and a protection circuit that provides multiple stages of protection to detect an erroneous synchronization state when the frame synchronization unit 6 performs frame synchronization. 8.

The digital wireless signal to be transmitted and received is a multiplex of multiple frames as shown in Figure 4, and each signal is a subframe, and each subframe has a main signal area, and inserts synchronization pattern bits, stuff information, etc. The format consists of a control bit area (C focus area).

The control bit area contains transmission line quality information.

The state of the antenna between digital radio relay stations, stuffing information for performing destuffing processing, synchronization pattern bits, etc. are inserted.

These insertion processes are performed by the signal processing circuit 2 on the transmitting side, and these extraction processes and detection processes are performed by the signal processing circuit 5 on the receiving side.

That is, the signal processing circuit 2 on the transmitting side inserts the status of the stuff pulse additionally inserted by the speed converter l into the control bit area as stuff information, and multiplexes the plurality of signals processed by the signal processing circuit 2 in the MAX unit 3. and transmits via the transmitting antenna ANT1.

The signal processing circuit 5 on the receiving side detects this stuffing information and sends out destuffing information for destuffing it, and the frame synchronization section 6 performs frame synchronization processing on the received main signal.

Note that the received frame synchronization pattern undergoes multiple stages of protection, and at this time it is determined whether or not the frame synchronization pattern is normal.

If the pattern is not a frame synchronization pattern, the protection circuit 8 sends a control signal for resynchronization to the frame synchronization unit 6, and redoes the frame synchronization process for the received main signal. That is, a hunting operation is performed.

[Problem to be solved by the invention]

In the above-mentioned frame synchronization processing, the determination as to whether or not the frame synchronization pattern is a regular frame synchronization pattern is performed based on the protection circuit 8 that performs multi-stage protection processing. If it exists,
In the conventional example described above, since it is determined that frame synchronization has been achieved, there is a problem in that it is difficult to restore a correct signal and the transmission quality is greatly impaired.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pseudo-synchronization prevention method that uses pseudo-synchronization determination information inserted into stuff information to establish correct frame synchronization.

[Means to solve the problem]

FIG. 1 shows a block diagram illustrating the invention in detail.

30 in the block diagram of the principle of the present invention shown in FIG.
50 is a multiplexing means for inserting the pattern signal into the stuff information and multiplexing it with the main signal, and 50 extracts the stuff information from the digital multiplexed signal received from the transmitting side and creates destuff information from this. - Output signal reception processing means; 90 compares the second pattern signal generated from the second pseudo synchronization prevention pattern generation means 200 and the first pattern signal extracted from the received main signal; 100 is a pseudo synchronization determination means for determining, and 100 is generated in response to stuff information indicating contents inserted and added to compensate for the lack of pulses due to the difference between the main signal read clock and the clock reproduced or created from the main signal. 200 is a first pseudo-synchronization prevention pattern generating means that is accessed by a control signal for re-establishing frame synchronization and generates a pattern signal for preventing pseudo-synchronization during main signal transmission/reception; a second pseudo-synchronization prevention pattern generating means for generating a second pattern signal having the same content as the first pattern signal using destuffing information, and such means is provided on the transmitting side and the receiving side of the digital radio device. This is a means to solve this problem.

[For production]

The multiplexing means 30 on the transmitting side inserts the first pattern signal generated from the first pseudo-synchronization prevention pattern generating means 100 into the main signal into the stuff information and transmits it.

The signal reception processing means 50 on the receiving side detects stuffing information from the received signal, creates and sends destuffing information based on the stuffing information.

The second pseudo-synchronization prevention pattern generation means 200 is accessed by the destuff information and sends a second pattern signal to the pseudo-synchronization determination means 90.

The pseudo synchronization determining means 90 compares the first pattern signal and the second pattern signal extracted from the received signal and determines whether or not they match, thereby making it possible to grasp the exact position of the frame synchronization pattern. Therefore, more accurate signal restoration is possible.

〔Example〕

The gist of the present invention will be specifically explained below with reference to an embodiment shown in FIG.

FIG. 2 shows a block diagram illustrating the invention in detail. Note that the same reference numerals indicate the same objects throughout the figures.

The present embodiment shown in FIG. 2 uses the multiplexing means 3 explained in FIG.
0, M having the same content as explained in FIG.
AX section 3a, first and second pseudo synchronization prevention pattern generation means 100.
200 is a pseudo-synchronization prevention pattern generating section 100a, 200a that generates a regular frame synchronization pattern, and a signal processing circuit 5a having the same content as that described in FIG. 3 serves as a signal reception processing means 50 on the receiving side.

The pseudo synchronization determination means 90 uses a pseudo synchronization prevention pattern (second
a pseudo-synchronization determination unit 90a that compares the pseudo-synchronization prevention pattern (corresponding to the first pattern signal) included in the received signal and determines whether they are the same. This is an example configured with

On the transmitting side, based on the stuff information sent from the speed converter l, a pseudo synchronization prevention pattern is generated from the signal processing circuit 2a (however, the signal processing circuit 2 described in FIG. 3 has an added function of sending a control signal). outputs a control signal for accessing the generator 100a, generates a pseudo synchronization prevention pattern from the pseudo synchronization prevention pattern generator 100a, and
It is sent to the AX section 3a.

The MAX unit 3a inserts this pseudo-synchronization prevention pattern into bits in the stuff information, multiplexes it with the main signal, and transmits it to the receiving antenna ANT2 via the transmitting antenna ANTI.

On the receiving side, after synchronizing the signals received by the frame synchronization unit 6, destuffing information is created based on the star/rough information detected when the received signal is processed by the signal processing unit 5a.
Thereby, the pseudo synchronization prevention pattern generating section 200a is accessed to generate the same original image synchronization prevention pattern as that on the transmitting side.

The pseudo synchronization prevention pattern from the pseudo synchronization prevention pattern generation section 200a is sent to the pseudo synchronization determination section 90a, and is compared with the pseudo synchronization prevention pattern from the sending side inserted into the received staff information to determine whether or not they match. judge.

The determination result is output to a protection circuit 8 for preventing the influence of code errors on the antenna, and is compared with a plurality of pseudo synchronization prevention patterns stored in advance in the protection circuit 8, and it is determined that pseudo synchronization is present. Then, the protection circuit 8 sends a control signal to the frame synchronization unit 6 to reestablish frame synchronization, and
The frame synchronization recovery (hunting) operation is performed again.

As for the pseudo synchronization judgment time processed as described above, for example, if we consider a case where the stuffing rate is 0.1, this is 1 in 10 multiframes if frame synchronization is normally achieved.
This will contain the bit stuff bit.

Therefore, pseudo-synchronization prevention patterns are compared once every 10 multi-frames, but in order to reduce the effects of errors due to original image synchronization prevention on the antenna or transmission path, pseudo-synchronization prevention patterns are compared multiple times. It is necessary to compare.

For this purpose, a time equivalent to several tens of multi-frames is required, but since frame synchronization can still be achieved normally, the pseudo synchronization determination time is negligible compared to the case where frame synchronization cannot be normally achieved.

In addition, the control pin (C bit) is used for stuff bit determination.
The presence or absence of a stuff bit is determined by multiplexing "H" into the signal and making a majority decision.

For example, when 3 or more bits out of 5 control bits (C bits) are “H”, it is determined that stuff bits are present (315)
This is a majority decision, etc.

Therefore, considering the randomness of the digital signal, the probability of determining that the control bit (C bit) has a stuff bit is 1/2.

That is, there are 25 possible values for 5 bits.

Among them, the number of times the number of "H" is 3 or more is 5 "H" - 1 way, 4 "H" - 5 ways, and 3 "H" -
There are 10 ways, and therefore 16 ways when there are three or more "H"s.

Therefore, 2'=16 out of 32 ways, and it can be determined that the stuff bit exists with a probability of 1/2. In the above, pseudo synchronization prevention patterns are compared once every two multiframes.

〔Effect of the invention〕

According to the present invention as described above, pseudo synchronization using the same pattern in the main signal as the frame synchronization pattern is reliably prevented.

1 is a speed conversion section, 2.2a, 5, 5a are signal processing circuits, 3.3a is a MAX section, 6 is a frame synchronization section, 8 is a protection circuit, 30 is a multiplexing means, 50 is a signal reception processing means, 90 90a is a pseudo-synchronization determination unit; 100.200 is a first/second pseudo-synchronization prevention pattern generation unit; 100a and 200a are pseudo-synchronization prevention pattern generation units;
are shown respectively.

[Brief explanation of the drawing]

FIG. 1 is a block diagram explaining the present invention in detail, FIG. 2 is a block diagram explaining the present invention in detail, FIG. 3 is a block diagram explaining the conventional example, and FIG. 4 is the frame format of the multiplexed signal. A diagram explaining , is shown, respectively. In the figure,

Claims (1)

[Claims] Re-establishing frame synchronization that occurs in response to stuff information indicating content inserted to compensate for the lack of pulses due to the difference between the main signal read clock and the clock reproduced or created from the main signal. a first pseudo-synchronization prevention pattern generation means (100) that is accessed by a control signal for generating a pattern signal for preventing pseudo-synchronization during main signal transmission/reception; A multiplexing means (30) for inserting the first pattern signal generated from the first pattern signal (100) into the stuff information and multiplexing it with the main signal is provided on the transmitting side constituting the digital radio device, and the received digital multiplexed signal a signal reception processing means (50) for extracting the stuffing information from therein and creating and outputting destuffing information based on the stuffing information; a second pseudo-synchronization prevention pattern generation means (200) that generates a second pattern signal having the same content as the first pattern signal; and a second pseudo-synchronization prevention pattern generation means (200) that generates a second a pseudo synchronization determination means (90) for comparing and determining whether or not the pattern signal matches the first pattern signal extracted from the received main signal; If the extracted first pattern signal matches the second pattern signal generated on the receiving side, it is determined that the main signal is in frame synchronization, and if they do not match, it is determined that the main signal is out of frame synchronization. A pseudo-synchronization prevention method is characterized in that it determines that there is a synchronization and performs a synchronization recovery operation.