JP3202379B2 - Packet frame transmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet frame transmission system in a PCM communication system, and more particularly, to a packet frame transmission system for transmitting a periodic frame signal via a packet frame transmission link.

[0002]

2. Description of the Related Art In general, in a PCM communication system, a multiplexed frame signal having a fixed period is transmitted from a transmission side to a reception side. A packet frame generated irregularly when necessary is transmitted using such a PCM communication system. Sometimes. As shown in FIG. 3, in the configuration of such a transmission system, the transmitting station 11 creates one packet frame every time the data length of the packet frame arrives in bit order from the input periodic frame signal, and transmits the packet signal. Send to link 12. The receiving station 13 sequentially receives and extracts packet frames from the transmitting station addressed to the own station, and then reconstructs them into a periodic multiplexed signal again. Conventionally, the configuration of this type of transmitting station 11 is shown in FIG.
FIG. 5 shows the format of the transmission signal created by the transmitting station 11. The transmitting station 11 shown in FIG. 4 includes a periodic frame signal input terminal 10, a packet frame signal output terminal 21, a periodic frame signal buffer memory 31, a packet frame generation circuit 32, a readout of the buffer memory 31, and an operation of the packet frame generation circuit 32. It comprises a packet transmission control circuit 33 for giving operation timing.

Next, the signal format and the timing relationship between the signal format of the PCM communication and the packet frame signal will be described with reference to FIG. As shown in the upper part of FIG. 5, in the periodic frame signal of the PCM communication, a multiplex signal of a fixed length and a predetermined number of channels is arranged between F and F using the frame synchronization signal F as a header signal. On the other hand, when the packet frame signal to be transmitted is present irrespective of the timing synchronized with the PCM frame synchronization signal shown in FIG. Since the speed is faster than the PCM signal speed,
Each of the n-th packet data C, the 0-th packet data C, and the first packet data C has a corresponding P
It is transmitted intermittently within the C1 bit of the CM periodic frame signal. In this case, the packet data is transmitted including the frame synchronization signal F. A, B, C, and F in the packet frame are a packet frame header signal A, a packet frame transmission order signal B, a periodic frame multiplexed data signal C on the packet frame, and a header signal F of the periodic frame signal, respectively. a, b, and c represent the number of bits, which are the number of bits of the packet frame header signal A, the packet frame transmission order signal B, and the periodic frame multiplexed signal C on the packet frame, respectively. The packet transmission control circuit 33 transfers the input periodic frame signal from the buffer memory 31 to the packet frame generating circuit 32 every time the input periodic frame signal is stored in the buffer memory 31 and stored in the buffer memory 31 in the order of arrival. A packet frame signal with the transmission order signal B added to the head is transmitted from the output terminal 21. The packet transmission order signal B is used when a packet frame transmission link loses some packet frames, for example, the transmission order signal B recognizes that the n-1th next n-th packet is lost, and the receiving side transmits the lost packet frame. Is used to reproduce the periodic frame signal, and integer values of 0 to N indicating the transmission order of the packet frames are sequentially and repeatedly used. Here, the receiving side checks the header signal F indicating the head of the periodic frame signal, decodes the periodic frame signal, and separates the time-division multiplexed signal from the packet frame. Since the extraction of the header signal F may include a signal equal to the header signal F and the header signal may be erroneous during transmission, a header having an appropriate length is used to accurately and stably check the header position. In addition to the need, a significant amount of circuitry is used at the receiving end to protect against errors. Check bits are also added to prevent pseudo-synchronization.

[0004]

As described above, in the conventional method, it is necessary to know the head of the periodic frame signal in order to decode the periodic frame signal and separate the time-division multiplexed signal. As described above, there is a disadvantage that the circuit configuration is complicated in order to accurately and stably check the frame synchronization signal F on the packet frame. An object of the present invention is to provide a method of transmitting frame position information which is simple and has good characteristics in such a periodic frame signal transmission system.

[0005]

According to the packet frame transmission method of the present invention, the frame data is converted into N (N is an integer of 2 or more) packet data frames and transmitted while securing the frame synchronization by the frame synchronization signal of the PCM communication. A transmitting station and receiving from the transmitting station over a packet signal transmission link,
In a packet frame transmission system having a receiving station that extracts the frame synchronization signal and demodulates packet data, a position between an end of a data signal of the packet data frame and a head position of the frame synchronization signal of the PCM communication. A position signal generation circuit that generates information in bit units;
A multiplexing circuit for inserting the position information into a head of a packet data signal in a first packet frame of the N packet data frames.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a transmitting station according to one embodiment of the present invention, and FIG. 2 is a signal format for explaining the present embodiment. 1, the same circuits as those shown in FIG. 4 have the same functions and configurations. That is, in this embodiment, the multiplexing circuit 30 and the position signal generating circuit are added.

Next, the configuration of the signal format on the transmitting side according to the present embodiment will be described with reference to FIG. The input cycle frame signal in the upper part of FIG. 2 has a signal format synchronized with the frame synchronization signal F of the PCM communication signal to transmit a fixed-length multiplex signal. The packet frame signal in the lower part of FIG. 2 repeatedly transmits the 0th to nth packet frame data sequentially at a timing irrelevant to the PCM communication signal as described above. Is different. That is, the frame header signal F is not written in the buffer memory 31. Instead, when the position signal generation circuit 34 has the packet frame transmission order signal B of a specific value (0th packet), the frame signal of the input periodic frame signal starts from the top of the frame. Is transmitted to the multiplexed data signal C via the multiplexing circuit 30.
Write to the beginning of. Therefore, as shown in FIG.
When the packet frame transmission order signal B is "0", the position signal D is added to the head of the multiplexed signal. On the receiving side, the head of the periodic frame signal can be obtained from the value of D of the packet frame in which the packet frame transmission order signal is "0". As the position signal, for example, the value of the frame counter of the periodic frame signal may be transmitted as it is, and the receiving side may set the value of the received frame counter of the periodic frame signal as it is with the value of D. Further, since the value of D whose position is fixed is a value uniquely determined by the periodic frame length and the packet frame configuration, protection against transmission line code errors can be realized by a simple circuit. In the present embodiment, an example in which the length of the packet frame is constant and the sum of the position signal length D and the multiplexed signal length C2 is always a constant value c is shown. It is clear that the present invention is not limited to this.

[0008]

As described above, according to the present invention, by providing a multiplexing circuit and a position signal generating circuit on the transmitting side,
On the receiving side, the head of the packet frame and the packet transmission order can be stably confirmed in the original packet transmission system, so that there is an effect that a conventional complicated circuit for extracting a frame synchronization signal from a multiplexed signal is not required. In addition, the same or higher frame synchronization characteristics can be obtained with a smaller amount of information than the conventional frame synchronization header signal, and there is an effect that tolerance against transmission path errors and pseudo synchronization can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a transmitting station according to an embodiment of the present invention.

FIG. 2 is a signal format illustrating an operation of the embodiment.

FIG. 3 is a configuration diagram of a general data signal transmission system.

FIG. 4 is a configuration diagram of a conventional transmitting station.

FIG. 5 is a signal format illustrating an operation of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Input terminal 11 Transmitting station 12 Packet signal transmission link 13 Receiving station 14 Output terminal of periodic frame signal 21 Output terminal 30 Multiplexing circuit 31 Buffer memory 32 Packet frame generating circuit 33 Packet transmission control circuit 34 Position signal generating circuit

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akihiro Miyamoto 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Seiichiro Shigaki 3-20-4 Nishishinbashi, Minato-ku, Tokyo Nippon Electric Engineering Co., Ltd. (72) Inventor Jin Agematsu 1-6-1, Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Co., Ltd. Within Nippon Telegraph and Telephone Corporation (56) References JP-A-4-98943 (JP, A) JP-A-4-138744 (JP, A) JP-A-3-231547 (JP, A) JP-A-4- 282936 (JP, A) JP-A-64-41538 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04J 3/00 H04L 7/00 H04L 12/00

Claims (2)

(57) [Claims] 1. A frame synchronization signal for PCM communication.
N (N is an integer of 2 or more) N
A transmitting station that converts the data into packet data frames and transmits the data;
Received from this transmitting station through the packet signal transmission link
And extract the frame synchronization signal to convert the packet data.
A packet frame transmission system having a demodulating receiving station
AndThe transmitting station, The data signal of the packet data frame
Signal end and the leading position of the frame synchronization signal of the PCM communication
Position signal generation that generates position information between the
A raw circuit, and the position information is stored in the N packet data files.
In the first packet frame of the frame.
A multiplexing circuit inserted at the beginning of the packet data signal.Equipment
e, The receiving station transmits the N-th packet frame data.
Extract the position information from only the first packet frame
When the frame synchronization signal is extracted, the other N-1 packets are extracted.
The packet frame data establishes synchronization based on the position information.
With means to do Packet frame transmission
Transmission method. 2. The method according to claim 1, wherein the position information of the position signal generating circuit is a period.
The bit counter of the frame counter of the frame synchronization signal
The packet frame transmission system according to claim 1, wherein the packet frame transmission system is generated by using a calculated value .