JPH03123226A - Scrambled data transmission system - Google Patents

Abstract

PURPOSE:To prevent the generation of disconnection of communication by dividing a consecutive bit string in a PN series for a long period as a scrambler initial value and using the value while being varied for each frame thereby inserting a scrambler to an input data. CONSTITUTION:A PN series generating circuit 2 in a transmission section 1 generates a PN series with a sufficiently longer period than the stage number of a reset scrambler 3. The scrambler 3 fetches a consecutive bit series by the stage number of the scrambler 3 sequentially from the PN series by one frame each and it is used as a scrambler initial value to scramble an input data 11. A PN series synchronizing circuit 6 in a reception section 5 fetches a scrambler initial value from a reception data 13 and reproduces the original PN series by taking synchronization of the PN series to apply bit error protection of the scrambler initial value. A reset descrambler 7 fetches a consecutive bit series by the number of stages of the descrambler 7 from the PN series recovered being an output of the circuit 6 and uses is as a scrambler initial value to descramble the data 13.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is utilized for a scrambled data transmission method using a PN sequence (pseudo-noise) sequence, and particularly for scrambled data transmission that prevents consecutive 0s or 1s in data. Regarding the method.

〔overview〕

The present invention, in a scrambled data transmission system using a PN sequence, changes the scrambler initial value for each frame and separates and uses consecutive bit strings of a long-term PN sequence as the scrambler initial value. It is now possible to prevent a malicious subscriber from intentionally inserting a pattern that cancels the scrambler into the input data, generating consecutive "0" bits or "1" bits and causing communication interruptions. It is something.

[Conventional technology]

Conventionally, this type of scrambled data transmission system has used fixed values as the initial values of the scrambler and descrambler. (For example, ANSI (American National Standards Institute) TI
XI/87-129R1).

[Problem that the invention seeks to solve]

In the conventional scrambled data transmission method described above, fixed values are used as the initial values of the scrambler and descrambler, so when transmitting bulk data, a malicious subscriber can use the scrambler. Continuous "0" by intentionally inserting data with a pattern that cancels out
bit or "1" bit, in particular, the NRZ
Another drawback is that there is a risk of communication interruption in systems using AMI codes.

It is an object of the present invention to eliminate the above-mentioned drawbacks so that a malicious subscriber can intentionally insert a pattern in the input data to counteract the scrambler and generate consecutive ``0'' bits or ``1'' bits. The object of the present invention is to provide a scrambled data transmission method that does not cause communication interruption.

[Means for solving problems]

The present invention provides a scrambled data transmission system comprising a transmitter having a means for scrambling input data and transmitting the scrambled data, and a receiver having a means for descrambling received data and reproducing the input data. The unit includes a PN sequence generation circuit, a reset type scrambler that takes the output of the PN sequence generation circuit as an input to a scrambler initial value, and scrambles the input data by changing the scrambler initial value every frame, and the reset type scrambler. The receiving section includes a multiplexing circuit that multiplexes the output and the output of the PN sequence generation circuit, and the receiving section includes a PN sequence synchronization circuit that receives received data as an input, and the output of the PN sequence synchronization circuit as a scrambler initial value input. The apparatus is characterized in that it includes a reset type descrambler that descrambles the received data.

[Effect]

The reset type scrambler and the reset type descrambler do not use a fixed value as the scrambler initial value, but separate continuous bit strings of a long-term PN sequence and use the scrambler initial value by changing it every frame.

Therefore, the subscriber who generates the input data series cannot easily find the initial value of the scrambler, and it becomes extremely difficult to generate input data with a pattern that cancels out the scrambler, thereby preventing communication interruptions. becomes possible.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a main part of an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing an example of its frame configuration.

According to FIG. 1, the present embodiment includes a transmitting section 1 having means for scrambling input data 11 and transmitting the same, and a receiving section 5 having means for descrambling received data 12 and reproducing the input data. In the scrambled data transmission method, the present invention is characterized in that the transmitting unit 1 includes a PN sequence generating circuit 2, and the output of the PN sequence generating circuit is used as a scrambler initial value input, and initializes the scrambler every l frame. The receiving section 5 includes a reset type scrambler 3 that scrambles the input data 11 by changing the value 9, and a multiplexing circuit 4 that multiplexes the output of the reset type scrambler and the output of the PN sequence generation circuit. It includes a PN series synchronization circuit 6 which receives received data 12 as input, and a reset type descrambler 7 which descrambles received data 12 by using the output of this PN series synchronization circuit as a scrambler initial value input.

According to FIG. 2, the frame includes a frame pattern 9, a scrambler initial value 9 and a reset scrambler output 9.

Next, the operation of this embodiment will be explained.

In the transmitter 1, a PN sequence generation circuit 2 generates a PN sequence with a cycle sufficiently long compared to the number of stages of the reset type scrambler 3. The reset type scrambler 3 sequentially resets each frame from this PN sequence.
A continuous bit string corresponding to the number of stages 0 is taken in, and input data 11 is scrambled using this as the scrambler initial value 9.

FIG. 3 shows a specific example of how to take the scrambler initial value 9 when using a 15-stage PN sequence and a 7-stage scrambler.

In Fig. 3, for the 11110001011 0PN sequence, the scrambler initial values 9 for the first frame, second frame, and third frame are, for example, No, 1, and No12.
, N003, . . .

In the transmitting section 1, the multiplexing circuit 4 multiplexes the scrambler initial value 9 and the reset type scrambler output 10, which are the outputs of the PN sequence generation circuit 2, for each frame according to the frame structure shown in FIG. 2, and transmits the multiplexed data. .

In the receiving section 5, the PN sequence synchronization circuit 6 receives the received data 1.
The scrambler initial value 9 is taken in from 2, the PN sequence is synchronized, the original PN sequence is reproduced, and bit error protection for the scrambler initial value 9 is performed.

The reset type descrambler 7 takes in consecutive bit strings for each stage of the reset type descrambler 7 from the reproduced PN sequence that is the output of the PN sequence synchronization circuit 6 in synchronization with the received frame phase for each frame. The scrambled received data 12 is descrambled using the scrambler initial value 9 to restore the original data sequence.

In the scrambled data transmission method of the present invention, PN
If the cycle of the sequence is long enough, the subscriber who generates the input data sequence cannot easily find the initial value of the scrambler, so it is extremely difficult to generate input data with a pattern that cancels the scrambler. becomes.

〔Effect of the invention〕

As explained above, the present invention allows a subscriber with malicious intent to intentionally insert a pattern that cancels the scrambler into input data to generate consecutive "0" bits or consecutive "1" bits, resulting in communication interruption. This has the effect of making it extremely difficult for this to occur and preventing it.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention. FIG. 2 is an explanatory diagram showing an example of a frame structure according to the present invention. FIG. 3 is an explanatory diagram showing an example of use of the scrambler initial value. DESCRIPTION OF SYMBOLS 1... Transmission part, 2... PN sequence generation circuit, 3...
Reset type scrambler, 4... Multiplexing circuit, 5...
- Receiving section, 6... PN series synchronization circuit, 7... Reset type descrambler, 8... Frame slam, 9...
- Scrambler initial value, 10... Reset type scrambler output, 11... Input data, 12... Received data.

Claims (1)

[Claims] 1. A scrambled data transmission system comprising a transmitter having means for scrambling input data and transmitting the same, and a receiver having means for descrambling received data and reproducing the input data. In the transmitter, the transmitting section includes a PN sequence generation circuit, a reset type scrambler that takes the output of the PN sequence generation circuit as an input to an initial value of the scrambler, and scrambles the input data by changing the initial value of the scrambler every frame; The receiving section includes a multiplexing circuit that multiplexes the output of the reset type scrambler and the output of the PN sequence generation circuit, and the receiving section includes a PN sequence synchronization circuit that receives received data as an input, and a multiplexing circuit that multiplexes the output of the PN sequence generation circuit. A scrambled data transmission method comprising: a reset type descrambler that descrambles the received data as an initial value input.