Encoding in a communication system

• US 6,571,369 B1
• Filed: 08/19/1999
• Issued: 05/27/2003
• Est. Priority Date: 08/19/1998
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Li, Jifeng
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): ABRAHAM, ESAW T
• Application Number:
  US09/377,456
• Time in Patent Office: 1,377 Days
• Field of Search: 714/792, 714/790, 714/786, 714/755, 375/265, 375/259
• US Class Current: 714/792
• CPC Class Codes: H03M 13/2771 Internal interleaver for turbo codes H03M13/2714 and H03M13/2725 take precedence
• CPC Class Codes: H03M 13/296 Particular turbo code structure
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27

Abstract

The present invention provides an optimum combinational configuration of an encoder and an interleaver of an encoding apparatus with the characteristics of a fading channel taken into account. Signals x_k and y_1k transmitted to a multiplexer are interleaved and input to a multiplexer. This enables the channel interleaver required between an encoder and multiplexer of a conventional apparatus to be removed. The encoding apparatus includes first and second encoders, first and second interleavers and a multiplexer which multiplexes an output from the first interleaving with an output from the second encoder. Conventionally, a channel interleaver has been provided as a countermeasure against fading. However, in this case, the delay of the channel interleaver is extended to reduce the bit error rate. Therefore, the channel interleaver is removed, and the interleaver is connected in parallel in the encoder so that the delay allowed for one interleaver is extended, thereby improving the transmission characteristics.

Claims

1. An encoding apparatus for a mobile communication system, comprising:

a first encoder encoding an input signal;

a first interleaver interleaving the input signal and an output from said first encoder;

a second interleaver interleaving the input signal;

a second encoder encoding an input from said second interleaver; and

a multiplexer multiplexing an output signal from said first interleaver with an output signal from said second encoder.

2. The apparatus according to claim 1, wherein said first and second encoders perform a turbo-encoding process.

3. The apparatus of claim 2, wherein plural combination of said second encoders and said second interleavers are provided.

4. The apparatus according to claim 1, which further includes a puncturing unit coupled between the output of said first encoder and an input of said first interleaver.

5. The apparatus of claim 1, which further includes a second puncturing unit coupled between an output of said second encoder and said multiplexer.

6. The apparatus of claim 1, wherein:

said first interleaver determines whether or not an interleaving process is performed on a tail bit of an encoded signal input to said first interleaver.

7. The apparatus of claim 1, which further comprises:

a channel interleaver interleaving an output of said multiplexer.

8. An encoding apparatus for a communication system, comprising:

a first interleaver interleaving an input signal;

a first encoder encoding an output from said first interleaver;

a second encoder encoding the input signal;

a second interleaver interleaving the input signal and an output from said second encoder; and

a multiplexer multiplexing outputs from said first encoder and said second interleaver.

9. A method of encoding an input signal for a mobile communication system, said method comprising the steps of:

(a) encoding the input signal;

(b) interleaving the input signal together and the signal encoded in said step (a);

(c ) interleaving the input signal;

(d) encoding a signal obtained in said step (c); and

(e) multiplexing a signal obtained in said step (b) with another signal obtained in said step (d).

10. The method of claim 9, wherein a turbo-encoding process is performed in said steps (a) and (d).

11. The method of claim 9, wherein a puncturing process is performed on a signal obtained in said step (a) before interleaving the signal in said step (b).

12. The method of claim 9, wherein a puncturing process is performed on a signal obtained in step (d).

13. The method according to claim 9, which further comprises the step of:

determining whether or not a tail bit of the encoded signal is to be interleaved.

14. The method according to claim 9, further comprising the step of:

interleaving the multiplexed signal obtained in said step (e).