Error detection/correction and fault detection/recovery – Pulse or data error handling – Digital data error correction
Reexamination Certificate
2000-07-06
2004-06-15
Chung, Phung M. (Department: 2133)
Error detection/correction and fault detection/recovery
Pulse or data error handling
Digital data error correction
C714S755000, C714S790000
Reexamination Certificate
active
06751772
ABSTRACT:
PRIORITY
This application claims priority to applications entitled “Rate Matching Device and Method for Data Communication System” filed in the Korean Industrial Property Office on Jul. 6, 1999 and assigned Serial No. 99-26978, and “Rate Matching Device and Method for Data Communication System” filed in the Korean Industrial Property Office on Jul. 10, 1999 and assigned Serial No. 99-27865, the contents of both of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a channel encoding device and method for a data communication system, and in particular, to a device and method for rate matching of channel-encoded symbols.
2. Description of the Related Art
Generally, in digital communication systems such as satellite systems, ISDN (Integrated Services Digital Network) systems, digital cellular systems, W-CDMA (Wideband Code Division Multiple Access) systems, UMTS (Universal Mobile Telecommunication Systems) and IMT-2000 (International Mobile Telecommunication-2000) systems, source user data is channel encoded with an error correction code before transmission in order to increase the reliability of the system. A convolutional code and a linear block code are typically used for channel encoding, and, for the linear block code, a single decoder is used. Recently, in addition to such codes, a turbo code is also being widely used, which is useful for data transmission and reception.
In multiple access communication systems which support multiple users and multi-channel communication systems with multiple channels, channel encoded symbols are matched to a given number of transmission channel symbols, in order to increase the efficiency of data transmission and to improve system performance. Such a process is called “rate matching” Rate matching is also performed to match the output symbol rate with the transmission symbol rate. Typical rate matching methods include puncturing or repeating parts of channel-encoded symbols.
A conventional rate matching device is shown in FIG.
1
. Referring to
FIG. 1
, a channel encoder
100
encodes input information bits (k) at a coding rate R=k
, and outputs encoded symbols (n). A multiplexer (MUX)
110
multiplexes the encoded symbols. A rate matching block
120
rate-matches the multiplexed encoded symbols by puncturing or repeating, and outputs the rate-matched symbols to a transmitter (not shown). The channel encoder
100
operates at every period of a symbol clock having a speed of CLOCK, and the multiplexer
110
and the rate matching block
120
operate at every predetermined period of a clock having a speed of n×CLOCK.
It should be noted that the rate matching device of
FIG. 1
is proposed to be applied to the case where a non-systematic code such as a convolution code or a linear block code is used for channel encoding. For symbols, channel-encoded with a non-systematic code such as a convolutional code or a linear block code, because there is no weight between symbols, i.e., since the error sensitivity of the encoded symbols output from the channel encoder
100
is similar for every symbol within one frame, it is possible that the symbols encoded by the channel encoder
100
are provided to the rate matching block
120
without distinction and undergo puncturing or repeating, as shown in FIG.
1
.
However, when using systematic codes, such as a turbo code, there is weight between symbols, so it is not good for the channel encoded symbols that are provided to the rate matching block
120
to equally undergo puncturing or repeating. Because the weight is not equal between information symbols and parity symbols, it is preferable for the rate matching block
120
to puncture parity symbols out of the turbo-encoded symbols, but not puncture the information symbols. As an alternative case, the rate matching block
120
can repeat the information symbols out of the turbo-encoded symbols to increase the energy of the symbols, but should not repeat the parity symbols, if possible. That is, it is difficult to use the rate matching device of
FIG. 1
when a turbo code is being used. This is natural in the light of the facts that the structure of
FIG. 1
is available for only non-systematic codes such as convolutional codes or linear block codes, and the turbo code has new properties different from those of the convolutional codes and the linear block codes.
Recently, to solve such a problem, a method has been proposed for rate matching the symbols channel-encoded with the turbo code. However, such a method can be used only when rate matching the turbo-encoded symbols, and cannot be used when rate matching the symbols channel-encoded with the existing convolutional codes or linear block codes.
Therefore, there is a need for a single device and method for rate matching both symbols channel-encoded with existing non-systematic code and symbols channel-encoded with systematic code. For example, a data communication system designed to support both non-systematic code and systematic code requires two different structures in order to rate match both codes, causing an increase in complexity. However, if it is possible to rate match the different codes using a single structure, the complexity of implementation will be reduced.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a device and method for rate matching both symbols channel-encoded with a non-systematic code and symbols channel-encoded with a systematic code, using a single structure, in a data communication system.
It is another object of the present invention to provide a device and method for selectively rate matching symbols channel-encoded with a non-systematic code or symbols channel-encoded with a systematic code in a data communication system supporting both non-systematic code and systematic code.
It is further another object of the present invention to provide a device and method for rate matching channel-encoded symbols to increase the efficiency of data transmission and to improve system performance in a data communication system.
To achieve the above and other objects, a device and method for matching a rate of channel-encoded symbols in a data communication system is proposed. The rate matching device and method can be applied to a data communication system which uses one or both of a non-systematic code (convolutional code or linear block code) and a systematic code (turbo code). The rate matching device includes a plurality of rate matching blocks, the number of the rate matching blocks being equal to a reciprocal of the coding rate of the channel encoder. The rate matching device can rate match the symbols encoded with a non-systematic code or the symbols encoded with a systematic code, by changing initial parameters including the number of input symbols, the number of output symbols, and the puncturing/repetition pattern determining parameters.
REFERENCES:
patent: 5909434 (1999-06-01), Odenwalder et al.
patent: 11-502679 (1999-03-01), None
patent: 2001-522198 (2001-11-01), None
patent: WO 96/23360 (1996-08-01), None
patent: WO 99/07076 (1999-02-01), None
patent: WO 99/23798 (1999-05-01), None
Japanese Office Action dated Jun. 17, 2003 issued in a counterpart application, namely Appln. No. 2001-508111, (No English translation).
European Search Report dated Aug. 2, 2002 issued in EP Appln. No. 00944447.2.
TS 1.22 V2.0.0 dated Apr. 1999.
Proposal for Rate Matching for Turbo Codes dated May 1999.
J.B. Cain, et al.,Punctured Convolutional Codes of Rate (n-1)
and Simplified Maximum Likelihood Decoding, IEEE Trans. Inform. Theory, vol. 1T-25, pp. 97-100, Jan. 1979.
G.D. Forney,Convolutional Codes I: Algebraic Structure, IEEE Trans. Inform. Theory, vol. IT-16, pp. 720-738, Nov. 1970.
Choi Soon-Jae
Kim Beong-Jo
Kim Min-Goo
Kim Se-Hyoung
Lee Young-Hwan
Chung Phung M.
Dilworth & Barrese LLP
Samsung Electronics Co,. Ltd.
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