JP3037837B2 - Restorer radio relay station - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a restorer radio relay station, and more particularly to one of working lines in digital multiplex radio.
The present invention relates to a wireless relay station adopting a restorer system when a failure occurs and switching from the failed line to a protection line.

[0002] In digital multiplex radio, in order to relieve fading that occurs in a radio section, typically, five radio sections are used as one unit and set as a switching section, for example, n + 1.
The system reserve system is adopted.

When switching from the working line to the protection line in the event of a failure, it is necessary to perform system switching without instantaneous interruption in order to remedy the line interruption, but at the same time, the system becomes asynchronous due to fading or the like. It is important that the resynchronization time from the state to the synchronization state is also as short as possible. Therefore, when a certain wireless section becomes asynchronous, pseudo synchronization data is transmitted to the next wireless section and the next wireless section is transmitted. A restorer method for synchronizing the data has already been proposed.

[0004]

2. Description of the Related Art A radio relay station adopting such a restorer system is shown in FIG. 8, and in a relay station 20 intermediate between a transmitting terminal station 10 and a receiving terminal station 30, a transmitting terminal which is a preceding station is provided. When a fault occurs in one of the n working lines W1 with the station 10 and a radio reception signal is disconnected or out of frame synchronization, the relay station 20 detects this and detects the working line. W1 is in the restorer mode, and the pseudo synchronizing signal from the restorer signal generation circuit 41 is transmitted to the transmission unit Tx.
And transmitted to the receiving station 30 of the next station.

[0005] The receiving end station 30 generates an alarm ALM1 out of frame synchronization until the intermediate relay station 20 puts the working line W1 into the restorer mode. 42 generates a bit error alarm ALM2 instead of the frame out-of-frame alarm ALM1 and sends it to the line switchers (SW) 11 and 31 of the sending terminal station 10 and the receiving terminal station 30 to switch the line to the protection line P0. To do.

FIG. 9 schematically shows a combination of a receiving unit and a transmitting unit in such a restorer radio relay station, and demodulates a signal generator 41 for a restorer and a signal received from a preceding radio station. And the demodulator 42 that performs the selector (S
EL) 43, and is connected to the selector 4
A modulator (MOD) 44 is connected to the output side of 3.

When the demodulator 42 detects a loss of frame synchronization when demodulating a received signal, the demodulator 42 outputs a data switching signal (frame synchronous / asynchronous signal) and supplies it to the selector 43. Then, the selector 43 selects the restorer signal from the restorer signal generator 41, modulates the restored signal with the modulator 44, and transmits the modulated signal to the next wireless section. When the demodulator 42 detects a transition from the out-of-frame state to the frame synchronization state, it also supplies a data switching signal to the selector 43 to switch back from the restorer signal generator 41 to the demodulator 42 side. Thus, the demodulated signal in the synchronized state is selected, modulated by the modulator 44, and sent out as a transmission signal.

[0008]

In such a conventional restorer radio relay station, since the modulator 44 does not have an error correction function, there is a problem that the error rate characteristic or the fading characteristic is deteriorated. there were.

Accordingly, an object of the present invention is to provide a restorer radio relay station to which an error correction function is added.

[0010]

In order to achieve the above object, a restorer radio relay station according to the present invention, as shown in the principle diagram of FIG. A demodulator 1 for demodulating the signal, an error correction decoder 2 for performing error correction decoding of the demodulated signal from the demodulator 1 to detect a loss of frame synchronization, and a PN signal for generating a pseudo-sync signal for a random restorer. When the error correction decoder 2 detects out-of-frame synchronization with the generator 3, the output signal of the error correction decoder 2 is switched to the pseudo-sync signal for the restorer, and the error correction decoder 2 performs frame synchronization. A selector 4 for switching the pseudo signal for restorer to an output signal of the error correction decoder 2 upon detection, an error correction encoder 5 for applying error correction to the output signal of the selector 4, By modulating the output signal of the issue unit 5 and a modulator 6 to be transmitted to the next radio zone.

In the present invention, the principle diagram of FIG.
As shown in (1), a demodulator 1 for demodulating a received signal from the preceding wireless station, an error correction decoder 2 for performing error correction decoding of the demodulated signal from the demodulator 1 and detecting loss of frame synchronization, A signal generator 9 for a restorer that generates a pseudo-synchronous signal for a restorer generated by performing signal processing on a minimum word stored in advance so as to reduce the correlation between data, and an error signal output from the error correction demodulator 2. An error correction encoder 5 for providing correction, and switching from the output signal of the error correction encoder 5 to the pseudo signal for the restorer when the error correction decoder 2 detects out-of-frame. Selects a pseudo signal for the restorer to an output signal of the error correction encoder 5 when detecting frame synchronization, and modulates an output signal of the selector 4 to a next wireless section. A modulator 6 that signals to, and a.

Further, in the present invention described above, a bit interleave transmission circuit 7 for performing a signal rearrangement process is provided in a preceding stage of the modulator 6 and a bit for returning the rearrangement of the signal in a subsequent stage of the demodulator 1 is provided. An interleave receiving circuit 8 may be provided.

[0013]

In the restorer radio relay station according to the present invention shown in FIG. 1, a received signal sent from a preceding radio station (not shown) is demodulated by a demodulator 1 and is preferably indicated by a dotted line. After passing through the bit interleave receiving circuit 8,
The error correction decoder 2 performs error correction decoding of the demodulated signal from the demodulator 1 to determine whether or not frame synchronization is maintained.

At this time, when a loss of frame synchronization (frame asynchronous) is detected, the selector 4 is switched to the restorer PN signal generator 3 by a control signal from the decoder 2, and this PN signal generator 3 Is transmitted to the error correction encoder 5, where the error correction is performed by the error correction encoder 5, and preferably through the bit interleave transmission circuit 7 indicated by a dotted line. Thus, the signal is transmitted from the modulator 6 to the next wireless section.

When the decoder 2 detects the transition from frame asynchronous to frame synchronous, the switch control signal is also supplied to the selector 4 so that the signal from the restorer signal generator 3 is shifted to the error correction decoder 2. The output signal of the error correction decoder 2 is subjected to error correction by the error correction encoder 5, and preferably transmitted through the bit interleave transmission circuit 7 from the modulator 6 to the next wireless section. Has become.

As described above, according to the present invention, a random pseudo-synchronization signal for a restorer is transmitted when a frame is asynchronous, and error correction is also performed on this pseudo-synchronization signal. Deterioration due to rate characteristics or fading can be suppressed.

Next, in the restorer radio relay station according to the present invention shown in FIG. 3, the error correction encoder 5 is moved not between the output side of the selector 4 but between the error correction decoder 2 and the selector 4. In addition, a restorer signal generator 9 for generating a restorer pseudo-synchronous signal is provided in place of the restorer signal generator 3 of FIG. 1, and the signal generator 9 reduces the correlation between data. Is output as a pseudo-synchronous signal.

That is, the demodulated and error-corrected decoded signal output from the error-correction decoder 2 is subjected to error correction again in the error-correction encoder 5 and sent to the selector 4. Is already a signal such that the correlation of data becomes small, and the signal generator 9
May be any signal equivalent to this.

When only one word frame is prepared as a restorer pseudo signal, for example, as shown in FIG. 2A, it is assumed that one word frame has N bits and the interleave depth is n. When
Input signal A input to bit interleave transmission circuit 7
Is the output signal B (see FIG. 3 (b)).
Is output in the vertical direction (interleave direction) of FIG. 2A as shown in FIG. 2C. At this time, when the PN signal generator 3 generates only one word frame, the output signal B
D _{11 is, ..., D 11, D 12} , ..., D 12, D 1N ..., spectrum strong as the now modulated output correlation data will be D _1N next identical data is the n consecutive normal correlation The spectrum may not be flattened like a spectrum without the distortion, and may be distorted, so that synchronization in the error correction decoder 2 may not be obtained.

Therefore, the pseudo-synchronous signal for the restorer generated from the signal generator 9 is obtained by processing the minimum word stored in advance so that the correlation between the data becomes small. The number of words provided in the generator 9 in advance is the minimum data.

[0021]

FIG. 4 shows an embodiment of the signal generator shown in FIG. 3. In this embodiment, a signal generator 9 is an N-ary counter for counting up to N corresponding to one word frame by a clock. 91 and a ROM for outputting data I and Q orthogonal to each other according to the count value of the counter 91
92 and the I and Q signals from the ROM 92
The signal processing unit 93 performs signal processing in accordance with one ripple carry signal RC and supplies the processed signal to the selector 4.

Embodiments of the signal processing section 93 in such a signal generator 9 are shown in FIGS. 5 to 7 and each will be described below.

First, the signal processing example (part 1) shown in FIG. 5 will be described. Data corresponding to one word frame shown in FIG. 2A is stored in the ROM 92 for each of the I signal component and the Q signal component. When this one word frame is 255 bits, only twice as much I data and Q data are stored.

Therefore, the counter 91 continues counting until N = 255, reads out data corresponding to each count value from the ROM 92 as I data and Q data, and outputs the data to the signal processing unit 93. Is sent to the selector 4 as it is, but since this ROM 92 has only one word frame for I and Q, the problem of continuous data when bit interleaving is performed as described above occurs.

Therefore, when the counter 91 counts up to N = 255, the ripple carry signal RC is supplied to the signal processing unit 93.
The I data and Q data similarly output from the second image limit [0 °] shown in FIG.
0 °], and similarly, when it reaches the next 255 bits, it is changed to the third image limit [180 °] and further to the fourth image limit [270 °]. The correlation between the data is always eliminated as shown in FIG.

In the signal processing section 93, in addition to the signal processing example (part 1) shown in FIG. 5, the data of the first to fourth image limits are rearranged as shown in FIG. Further, the correlation between data can be weakened.

Further, as shown in the signal processing example (part 3) shown in FIG. 7, in the error correction encoder 5 or the bit interleave transmission circuit 7 shown in FIGS. FIG. 7B shows a state in which an error can occur in the operation result in addition to the correct syndrome operation shown in FIG. 7A (which is equivalent to the operation shown in FIG. 5) in consideration of the protection characteristics. As shown, the data can be further inserted into the rearranged state in FIG. 6 to eliminate the correlation between the data.

As described above, any data is obtained by inverting / non-inverting the data of one word frame data (I data, Q data) or by exchanging I and Q data.
It is possible to obtain data with little correlation without increasing the capacity of the N.92.

[0029]

As described above, according to the restorer radio relay station according to the present invention, the error correction decoding of the demodulated signal from the demodulator is performed by the error correction decoder, the loss of frame synchronization is detected, and the PN signal is detected. An error correcting encoder for selecting a random pseudo-sync signal for a restorer from a generator (or a pseudo-sync signal for a restorer generated by performing signal processing on a minimum word stored in advance so as to reduce the correlation between data). Either gives error correction and modulates it with a modulator and transmits it to the next wireless section, or performs signal processing on a pre-stored minimum word so as to reduce the correlation between data instead of a random restore pseudo-synchronous signal. The pseudo-synchronous signal for the restorer generated by the above is switched from the signal subjected to the error correction again by the error correction decoder 2 to the error correction encoder 5 and modulated. And then, is transmitted to the line segment, the improved characteristics of such instantaneous switching of the line for always error rate performance and fading will be error correction function is added to the transmission data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing in principle the configuration (No. 1) of a restorer radio relay station according to the present invention.

FIG. 2 is a diagram illustrating bit-interleaved signal sequence conversion used in a restorer radio relay station according to the present invention.

FIG. 3 is a block diagram showing in principle a configuration (No. 2) of a restorer radio relay station according to the present invention.

FIG. 4 is a block diagram showing one embodiment of a signal generator used in a restore relay radio relay station according to the present invention.

FIG. 5 is a diagram showing an example (part 1) of signal processing in the restorer radio relay station according to the present invention.

FIG. 6 is a diagram illustrating a signal processing example (part 2) in the restorer radio relay station according to the present invention.

FIG. 7 is a diagram illustrating a signal processing example (part 3) in the restorer radio relay station according to the present invention.

FIG. 8 is a block diagram showing an overall configuration of a conventional restorer system.

FIG. 9 is a block diagram schematically illustrating a receiving unit and a transmitting unit in a conventional restorer radio relay station.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 demodulator (DEM) 2 error correction decoder 3 PN signal generator for restorer 4 selector (SEL) 5 error correction encoder 6 modulator (MOD) 7 bit interleave transmission circuit 8 bit interleave reception circuit 9 signal for restorer Generator In the drawings, the same reference numerals indicate the same or corresponding parts.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Aikawa Nippon Telegraph and Telephone Corporation, 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo (56) References JP-A-63-129740 (JP, A) JP-A-3-71738 (JP, A) JP-A-2-53330 (JP, A) JP-A-3-89735 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) H04L 1 / 22 H04B 1/74

Claims (3)

(57) [Claims] 1. A demodulator (1) for demodulating a signal received from a preceding wireless station, and an error correction decoding for performing error correction decoding of the demodulated signal from the demodulator (1) to detect a loss of frame synchronization. (2) and a PN for generating a pseudo-sync signal for a random restorer
When the signal generator (3) and the error correction decoder (2) detect out-of-frame, the output signal of the error correction decoder (2) is switched to the restorer pseudo-synchronization signal and the error correction is performed. Decoder
(2) a selector (4) for switching from the restored pseudo signal to the output signal of the error correction decoder (2) when detecting frame synchronization, and applying error correction to the output signal of the selector (4). A restorer radio relay comprising: an error correction encoder (5); and a modulator (6) for modulating an output signal of the error correction encoder (5) and transmitting the modulated signal to a next radio section. Bureau. 2. A demodulator (1) for demodulating a signal received from a preceding wireless station, and an error correction decoding for performing error correction decoding of the demodulated signal from the demodulator (1) to detect a loss of frame synchronization. A restorer signal generator (9) for generating a restorer pseudo-synchronization signal generated by performing signal processing on a pre-stored minimum word so as to reduce the correlation between data; An error correction encoder (5) for providing error correction to the output signal of the demodulator (2), and an output signal of the error correction encoder (5) when the error correction decoder (2) detects out of frame. To the restorer pseudo signal and the error correction decoder (2)
A selector (4) for switching the pseudo signal for the restorer to the output signal of the error correction encoder (5) when detecting the frame synchronization, and modulating the output signal of the selector (4) for the next radio section. A modulator (6) for transmitting a signal to a wireless relay station. 3. A signal interleaving transmission circuit (7) for rearranging signals is provided in a stage preceding the modulator (6), and the rearrangement of the signals is restored in a stage subsequent to the demodulator (1). The radio relay station according to claim 1, further comprising a bit interleave receiving circuit (8).