Turbocoding methods with a large minimum distance, and systems for implementing them

• US 20020099997A1
• Filed: 09/28/2001
• Published: 07/25/2002
• Est. Priority Date: 10/10/2000
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Piret, Philippe
• Granted Patent: US 6,993,698 B2
• Time in Patent Office: Days
• US Class Current: 714/781
• CPC Class Codes: H03M 13/23 using convolutional codes, e.g. unit memory codes
• CPC Class Codes: H03M 13/2771 Internal interleaver for turbo codes H03M13/2714 and H03M13/2725 take precedence
• CPC Class Codes: H03M 13/2996 Tail biting

Abstract

Turbocoding methods use a first RSC coder operating on sequences of binary data a, and a second RSC coder operating on binary sequences a* each obtained from a by means of a predetermined permutation. These permutations are designed so that, for any sequence a represented by a polynomial divisible by the recursion polynomial, the associated sequence a* is also represented by a polynomial divisible by said recursion polynomial. These permutations are relatively simple to implement, and are applicable to all the data sequences a whose length is a multiple of the period of the recursion polynomial. In addition, once the transfer functions of said coders and said sequence length have been chosen, it is possible to select, amongst the corresponding permutations, the one which will probably offer the highest minimum distance of the code. Application to devices and apparatus implementing these methods.

Claims

1. Method of turbocoding for the transmission of information in which, a first polynomial with binary coefficients g(x) of degree d and with a constant term equal to 1 having been predetermined, first of all said information is presented in the form of binary sequences u of length

2. Turbodecoding method, characterized in that it makes it possible to decode received sequences which have been transmitted after having been coded by means of a turbocoding method according to claim 1.

4. Device (901) for coding sequences of data intended to be transmitted by means of a turbocoding method according to claim 1, characterized in that it has:

means (30) for obtaining, for each sequence of data u, said sequence a associated with u by extending the sequence u by means of said d padding bits, and

at least one turbocoder (40) having an interleaver π

₁ able to effect the permutation provided for in said method.

5. Decoding device (1101) intended to implement a turbodecoding method according to claim 2, characterized in that it has:

at least one turbodecoder (300) having two interleavers π

₁ able to effect the permutation provided for in said method, and a deinterleaver π

₂ able to reverse this permutation, and

means (335) for producing a binary sequence û

by removing the last d bits of the estimated sequence â

obtained at the end of the turbodecoding of the received sequences a′

, b′ and

c′

corresponding respectively to said transmitted sequences a, b, and c.

6. Apparatus for transmitting coded digital signals (48), characterized in that it has a coding device according to claim 4, and in that it has means (906) for transmitting said coded sequences a, b, and c.

7. Apparatus for receiving coded digital signals (333), characterized in that it has a decoding device according to claim 5, and in that it has means (1106) for receiving said sequences a′

, b′

, and c′

.

8. Telecommunications network, characterized in that it has at least one apparatus according to claim 6 or claim 7.

9. Data storage means which can be read by a computer or a microprocessor storing instructions of a computer program, characterized in that it makes it possible to implement a method according to any one of claims 1 to 3.

10. Means of storing data which are removable, partially or totally, which can be read by a computer and/or a microprocessor storing instructions of a computer program, characterized in that it makes it possible to implement a method according to any one of claims 1 to 3.

11. Computer program containing instructions such that, when said program controls a programmable data processing device, said instructions mean that said data processing device implements a method according to any one of claims 1 to 3.

3. Method for determining a turbocoding method in which, a first polynomial with binary coefficients g(x) of degree d and with a constant term equal to 1 having been predetermined, first of all said information is presented in the form of binary sequences u of length