KR950012327B1 - Detection and generation of real time section overhead byte of physical layer in the asynchronous transfer mode system - Google Patents

Abstract

The apparatus and method is for detecting real time overhead byte of STM-1 frame. The apparatus includes a 3-phase signal generator(21) for generating signals needed to BIP24 calculation, a position signal generator(22) for generating enable signals for special bytes(B2,Z2) in section overhead bytes, and an overhead generator(23) for executing BIP24 calculation, for generating a section overhead byte(Z2), and for storing whole overhead.

Description

Apparatus and method for real-time section overhead byte detection and generation of physical layer receiver in asynchronous transmission mode system

1 is an exemplary configuration diagram of a wideband ISDN-1 class physical layer receiver to which the present invention is applied.

2 is a block diagram showing a schematic configuration of an apparatus for real-time section overhead byte detection and generation of a physical layer receiver according to the present invention.

3 is a detailed block diagram of an embodiment of the BIP-24 code three-phase control signal generator of FIG.

4 is a detailed block diagram of an embodiment of the B2 and Z2 byte position indication signal generator of FIG.

FIG. 5 is a detailed block diagram of an embodiment of the overhead generator of FIG.

6 is a view for explaining the range and method of BIP-24 code calculation in the STM-1 frame according to the present invention.

7 is a flow chart of the B2 and Z2 byte control method according to the present invention.

* Explanation of symbols for main parts of the drawings

11 photoelectric conversion unit 12 synchronization unit

13: STM-1 overhead remover 14: B2 detection and Z2 generator

15: Cell boundary recognition and mixing device 16: Overhead storage unit

21: BIP-24 code three-phase signal generator

22: B2 and Z2 position indication signal generator

23: overhead generating unit 31: payload envelope generating unit

32: parity calculation envelope generator 33: three-phase signal generator

In the present invention, when the physical layer is implemented to have a STM-1 (Synchronous Transport Module-1) transmission rate in a synchronous multi-level (SDH) environment in a broadband integrated information network (B-ISDN), section error monitoring And an apparatus and method for detecting and generating section overhead bytes of an STM-1 frame related to reporting.

For reference, Synchronous Transport Module-1 (STM-1) has an overhead of 90 bytes, where 81 bytes (9 bytes × 9 bytes) accommodate ATM cells, and section overhead parity (B) of the remaining 9 bytes. 3 bytes are used, and 3 bytes are used as section overhead parity (Z), and the rest are used as bytes C1 for indicating STM-1 and bytes J1 for tracking.

In the STM-1 frame, the section error monitoring function follows a bit interleaved parity-24 encoding method that provides even parity values by three B2 bytes, and the section error reporting function uses three Z2 bytes. It is provided by informing the end-point of the parity error generated during the transmission by the 18th to 24th bits, that is, 7 bits.

Next, briefly introduce the definition of the function and encoding of B2 and Z2 bytes, the existing Synchronous Optical NETwork (SONET) system STS-1 and multiplexed STS-3 (Synchronuos Transport Signal-3) and STS- It provides service of 3c (Synchronuos Transport Signal-3c) transmission rate, but the exact system function specification is not defined for the use of B2 and Z2 byte.

The BIP-24 encoding method is calculated in SONET system for B2 bytes, but its access is not made in real time, and the processing of Z2 bytes is not defined at all.

However, when the physical layer of the broadband integrated information network provides 155.520Mbs transmission speed of STM-1 class in a synchronous multilevel environment, the section error reporting function by Z2 bytes must be provided.

The present invention has been proposed by such a necessity, and has been proposed in the existing system when adopting an asynchronous transmission mode (ATM) transmission scheme having a physical layer in a synchronous multi-system (SDH) environment in a broadband integrated information communication network (B-ISDN). Asynchronous transmission that provides the section error monitoring and reporting function by performing section overhead byte control of the STM-1 frame in real time while implementing the STM-1 (Synchronuos Transport Module-1) transmission rate while accepting the structure as it is. An object of the present invention is to provide an apparatus and method for real-time section overhead byte detection and generation of a physical layer receiver in a mode system.

In order to achieve the above object, in order to achieve the above object, the physical layer has a transmission rate of STM-1 (Synchronuos Transport Module-1) in a synchronous multi-layer (SDH) environment in a broadband integrated information network (B-ISDN), A device for detecting and generating section overhead bytes of an STM-1 frame related to section error monitoring reporting, wherein the reset signal, the system clock, and the frame sync signal are connected to each other to perform a specific encoding (BIP-24) calculation. Three-phase signal generating means for generating control signals necessary for; A position indication signal generating means connected to the overhead input clock and the overhead input sync signal, for locating the specific bytes B2 and Z2 from the section overhead bytes and generating an enable signal thereto; And connected to the system clock and frame sync signal, the overhead input clock and overhead input sync signal, and overhead input data, connected to a frame data bus, and the three-phase signal generating means. An overhead generating means for performing encoding (BIP-24) calculation according to the control signal provided by the position indicating signal generating means, generating a specific section overhead byte (Z2) value, and allowing the entire overhead to be stored. It is characterized by.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

First, as an example in which the apparatus proposed in the present invention can be used, FIG. 1 is an exemplary diagram schematically showing the configuration of a B-ISDN STM-1 physical layer receiving unit to which the present invention is applied. As an example, a receiver of a wideband Telecommunication Network Tb interface (broadband "T" interface) or Sb interface (broadband "S" interface) is shown.

The photoelectric conversion unit 11 converts the optical data through the optical receiver into bit data of the electrical signal, and the synchronization unit 12 synchronizes the frame and converts the serial bit stream into data in bytes. The STM-1 overhead remover 13 performs a function of eliminating the section and pass overhead related to payload transmission. In this case, the B2 detection and Z2 generator 14 proposed by the present invention is configured to receive the received byte unit. Perform the calculation and BIP-24 code on the data, find the Z2 value and send it to the overhead storage 16. The cell boundary recognition and blending device 15 performs a cell boundary recognition and blending function as a control unit for an ATM cell.

FIG. 2 is a block diagram showing a schematic configuration of an apparatus (corresponding to B2 detection and Z2 generating unit of FIG. 1) for real-time section overhead byte detection and generation of a physical layer receiver according to the present invention. The BIP-24 symbol three-phase signal generator, 22 denotes the B2 and Z2 position indication signal generators, and 23 denotes the overhead generator.

As shown in the figure, the apparatus for B2 and detection and Z2 generation according to the present invention is connected so that a reset signal, a system clock and a frame sync signal are applied, and control signals necessary for BIP-24 encoding calculation, that is, A BIP-24 coded three-phase signal generator 21 for generating each byte phase signal when three bytes are constituted by one block; A position indication signal generator 22 connected to the overhead input clock and the overhead input sync signal, the B2 and Z2 finding a position among the section overhead bytes and generating an enable signal thereto; The system clock and frame sync signal, the overhead input clock and overhead input sync signal, and overhead input data are connected to each other, and are connected to a frame data bus, and the BIP-24 coded three-phase signal. The overhead generator 23 performs BIP-24 encoding calculation according to the control signals provided by the generator 21 and the position indication signal generator 22, generates a Z2 value, and stores the entire overhead in the buffer. Equipped with. Detailed configuration of each of these parts will be described with reference to FIGS. 3 to 5 below.

FIG. 3 is a detailed block diagram of an embodiment of the BIP-24 code three-phase control signal generator of FIG. 2, in which 31 is a payload envelope generator, 32 is a parity calculation envelope generator. Are three-phase signal generators respectively.

As shown in the figure, a payload envelope generator 31 connected to apply a system clock and a frame sync signal to an input terminal, and outputs R9 and Pld of the system clock and payload envelope generator 31. The parity calculation envelope generator 32 connected to the input terminal and the output PEN of the system clock parity calculation envelope generator 32 are connected to the input terminal to receive the received envelope signal PEN. A three-phase signal generator 33 for generating and outputting signals P1, P2, and P3 separated into three phases is provided.

The payload envelope generator 31 generates the control signals R9 and Pld in synchronization with the frame sync. The frame sync signal takes 8 kHz frequency to keep the entire system in sync. Therefore, an STM-1 frame is sent once per 125usec, and the sync pulse is indicated at the third A2 byte, where the framing processing for the STM-1 frame is completed. The R9 signal is a 72 Hz sync signal representing one row of the STM-1 frame. Therefore, nine R9 signals are generated per frame. The Pld signal is an enable signal indicating a payload of an STM-1 frame, is 0 at section overhead and AU-4 pointer positions, and is activated at 261 pass overheads and C-4 (Container 4) payload positions. Keep 1 That is, the enable signal for the VC-4 (Vertual Container 4) payload. The parity calculation envelope generator 32 generates an envelope signal for the range in which the BIP-24 code is calculated using the control signal provided from the payload envelope generator 31. to be. In the present invention, since B2 provides a digital section error monitoring function, rather than calculating even parity for the entire STM-1 frame, the overhead of the regenerator section is not included in the calculation range. The enable signal PEN is an envelope for this. The three-phase signal generator 33 generates signals P1, P2, and P3 that separate the envelope signal PEN received from the parity calculation envelope generator 32 into three phases.

FIG. 4 is a detailed block diagram of an embodiment of the B2 and Z2 byte position indicating signal generators of FIG. 2, in which 41 is a B2 envelope generator, 42 is a Z2 envelope generator, and 43 is a timing alignment unit. This is to provide a signal indicating a position for the B2 and Z2 bytes, a B2 envelope generator 41 which generates a 24-bit B2 byte size in synchronization with an overhead input sink, and a 7-bit Z2 byte size. The B2 and Z2 bytes of the Z2 envelope generator 42 for generating an envelope signal for the B2 envelope generator 42 and the envelope signal of the magnitude calculated by the B2 envelope generator 41 and the Z2 envelope generator 42. The timing alignment part 43 which locates a position is provided. Here, both the overhead clock and the overhead sink are made from the system clock. That is, the system clock is divided and provided by an external device such as the STM-1 overhead remover or clock generator of FIG. 1, and the overhead sink is a signal having an 8 kHz frequency, and the C1 byte (STM) of the overhead data stream It is the activation pulse at the most significant bit (MSB) of the function.

5 is a detailed block diagram of an example of the overhead generator of FIG. 2, which is provided by the BIP-24 code three-phase signal generator 21 and the B2 and Z2 position indication signal generator 22 of FIG. An example of the overhead generating unit that receives the control signal to detect B2 and generates Z2.

As shown in the figure, the overhead generation unit according to the present invention is connected to each of the frame sink, system clock and frame data is applied to each of the three BIP-8 code calculation unit 51 is provided to be assigned one for each phase And three BIP-8 code storage units 52 connected to the frame sync signal and connected to output terminals of the BIP-8 code calculator 51 so as to receive parity for each phase. A parallel / serial conversion unit 53 connected to the head input clock and the overhead input sync signal and connected to the output terminals of the three BIP-8 code storage units 52 so that parallel BIP-8 codes are input thereto; A converter control logic 54 connected to the overhead input clock and a B2LI signal from a timing aligner (see 43 in FIG. 4) and providing a control signal of the parallel / serial converter 53; Above overhead An input clock, an overhead input sync signal, and an overhead input data and B2LI and Z2LI signals from the timing alignment unit (see 43 in FIG. 4) are connected to each other, and the B2 stream is input from the parallel / serial conversion unit 53. A parity comparison and error counting unit 55 for receiving an overhead and write clock and receiving an overhead output clock, and receiving the overhead and write clocks from the parity comparing and error counting unit 55. And an overhead storage unit 56 for inputting and applying the overhead output data to the outside, and receiving the overhead input sink and the overhead output sink signals, and controlling the control signal of the overhead storage unit 56. A storage control logic 57 is provided.

The three-phase control signals P1, P2, and P3 output from the three-phase signal generator (see 33 in FIG. 3) are control signals for each phase, and three BIP-8 codes for receiving frame data are calculated. The unit 51 adjusts to successively even-parity. Accordingly, the three parity values calculated in the Hannan STM-1 frame are transferred to each BIP-8 code storage 52 in synchronization with the frame sync signal for the next STM-1 frame, and the parallel / serial conversion unit At 53 it is converted to a BIP-24 code value. Control signals required by the parallel / serial converter 53, i.e., multiplexed control signals required to convert three serial parity values to one BIP-24, are provided by the changer control logic 54. The parity note and error counting unit 55 controls B2LI, which is a B2 byte position indicating signal provided by the timing aligning unit (see 43 in FIG. 4) of the B2 and Z2 position indicating signal generating units (see 22 in FIG. 2). And is written to the Z2 byte position, which is the overhead of the currently received STM-1 frame. The entire overhead data is then stored in the overhead storage 56 by the write clock. Further, the read and write control signals for the overhead storage 56 are provided from the storage control logic 57.

FIG. 6 shows a method of calculating even parity using the SIP-1 frame controlled by the BIP-8 code calculator 51 of FIG. The PEN signal generated by the parity calculation envelope generator 22 of FIG. 3 represents the envelope of the hatched portion 61, and the P1, P2, and P3 signals generated by the three-phase signal generator 33 are Since the parity for each phase of each block shown in (62) of this figure is calculated, each P1 signal becomes an enable signal for each phase. Thus, the overall BIP-24 code and calculation are completed by performing the XOR function for the same bit position of each block.

FIG. 7 is a flowchart illustrating the B2 and Z2 byte control method according to the present invention, which briefly illustrates a control flow for a function performed in FIG.

Looking at the execution process, the BIP-24 code calculation staff 71 detects B2 for the STM-1 frame received in real time, and the stamp 72 and stamp 73 generate Z2 values and store them. As a function, the stamp 72 compares a BIP-24 coded calculation value with a B2 byte value and performs an error coefficient. The staff 73 encodes Z2 bytes and stores overhead according to the result of the staff 72.

At this time, the staff 71 and the staff 72 and 73 control different frames, respectively. This is because the B2 byte value at the transmitter, that is, the B2 byte value provides the even parity value for the previous frame, the receiver calculates the BIP-24 code of the currently received frame and compares it with the B2 byte value of the next frame. shall.

Therefore, when the step 71 performs a function on the i-th frame, the steps 72 and 73 perform processing on the i + 1 th frame overhead.

The present invention, which is configured and performed as described above, provides a monitoring and reporting function for bit errors occurring on a transmission line when a physical layer is configured in a synchronous multi-level environment in a broadband integrated information communication network, thereby providing an image. It has the effect of improving the reliability and efficiency of broadband services such as conference, high speed data transmission, high definition TV and high speed LAN / MAN.

Claims (5)

STM-1 related to section error monitoring and reporting, in order to implement the STM-1 (Synchronous Transport Module-1) transmission rate under the synchronous multi-level (SDH) environment in the B-ISDN. An apparatus for detecting and generating section overhead bytes of a frame, comprising: a reset signal, a system clock, and a frame sync signal connected to each other to generate a control signal necessary for calculating a specific encoding (BIP-24). Phase signal generating means 21; An overhead input clock and an overhead input sync signal are connected to each other, and the position indication signal generating means 22 locates the specific bytes B2 and Z2 among the section overhead bytes and generates an enable signal thereto. ; And the system click and frame sync signal, the overhead input clock and overhead input sync signal, and overhead input data are connected and connected to a frame data bus, wherein the three-phase signal generating means ( 21) and the overhead of performing encoding (BIP-24) calculation and generating a specific section overhead byte (Z2) value according to the control signal provided from the position indication signal generating means 22 and storing the entire overhead. Generating means 23; Apparatus for real-time section overhead byte detection and generation of the physical layer receiver in the asynchronous transmission mode system, characterized in that it comprises a. 2. The apparatus of claim 1, wherein the three-phase signal generating means (21) comprises: a payload envelope generating means (31) connected to apply a system clock and a frame sync signal to an input terminal; Parity calculation envelope generating means (32) coupled such that the system clock and outputs (R9, Pld) of the payload envelope generating means (31) are applied to an input terminal; And an output PEN of the system clock and the parity calculation envelope generating means 32 are applied to an input terminal, and are signals P1, P2, which separate the received envelope signal PEN into necessary phases. Three-phase signal generating means 33 for generating and outputting P3); Apparatus for real-time section overhead byte detection and generation of the physical layer receiver in the asynchronous transmission mode system comprising a. 3. The position indication signal generator (22) according to claim 2, further comprising: B2 envelope generating means (41) for generating a 24-bit specific byte (B2) size in synchronization with an overhead input sink; Z2 envelope generating means 42 for generating an envelope signal for a specific byte (Z2) size of 7 bits; Timing alignment means (43) for locating the specific bytes (B2, Z2) from an envelope signal having a magnitude calculated by the B2 envelope generating means (41) and the Z2 envelope generating means (42); Apparatus for real-time section overhead byte detection and generation of the physical layer receiver in the asynchronous transmission mode system comprising a. The at least one sign calculating means (51) according to claim 3, wherein said overhead generating means (23) is connected so that frame sinks, system clicks, and frame data are respectively applied, and is assigned to be assigned one for each image. ); At least one code storing means (52) connected to be applied with the frame sync signal and connected to an output terminal of the code calculating means (51) to receive parity for each phase; Parallel / serial conversion means (53) connected to be applied with an overhead input clock and an overhead input sink signal, and connected to an output terminal of the code storage means (52) so that a specific code in parallel (BIP-8) is inputted; A conversion control means (54) connected to the overhead input clock and a specific control signal (B2LI) from the timing alignment means and providing a control signal to the parallel / serial conversion means (53); The overhead input clock, the overhead input sync signal, the overhead input data, and a specific control signal (B2LI, Z2LI) from the timing alignment means are connected so as to be applied, and from the parallel / serial conversion means (53). Parity comparison and error counting means 55 for receiving an output (stream B2) and outputting an overhead and a write clock; An overhead storage means (56) connected to receive an overhead output clock, for inputting overhead and write clocks from the parity comparison and error counting means (55) and applying overhead output data to the outside; Storage control means (57) connected to receive the overhead input sink and the overhead output sink signal, and providing a control signal to the overhead storage means (56); Apparatus for real-time section overhead byte detection and generation of the physical layer receiver in the asynchronous transmission mode system comprising a. In order to implement a specific encoding (BIP-24) to implement the STM-1 (Synchronous Transport Module-1) transmission rate under a synchronous multi-level (SDH) environment in a broadband integrated telecommunication network (B-ISDN). Three-phase signal generation means 21 for generating necessary control signals, and position indication signal generation means 22 for locating specific bytes B2 and Z2 from the section overhead bytes and generating enable signals thereto; And perform encoding (BIP-24) calculation according to control signals provided from the three-phase signal generating means 21 and the position indicating signal generating means 22, and generating a specific section overhead byte (Z2) value. Section overhead of an STM-1 frame related to section error monitoring and reporting, in an apparatus for section overhead byte detection and generation having an overhead generating means 23 which allows the entire overhead to be stored. A method for performing a byte detection and generation, (71) a first step of performing a specific code (BIP-24) calculated on the current frame; (72, 73) a second step of generating another specific byte (Z2) value by comparing the value calculated in the first step (71) with a specific byte (B2) value of the next frame; A method for real-time section overhead byte detection and generation of a physical layer receiver in an asynchronous transmission mode system, characterized in that is performed.