Pulse or digital communications – Receivers – Particular pulse demodulator or detector
Reexamination Certificate
1999-03-31
2004-06-22
Tran, Khai (Department: 2631)
Pulse or digital communications
Receivers
Particular pulse demodulator or detector
Reexamination Certificate
active
06754290
ABSTRACT:
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates to coding. More particularly, the present invention relates to a novel and improved technique for performing maximum a posteriori probability (MAP) decoding.
II. Description of the Related Art
“Turbo coding” represents an important advancement in the area of forward error correction (FEC). There are many variants of turbo coding, but most use multiple encoding steps separated by interleaving steps combined with iterative decoding. This combination provides previously unavailable performance with respect to noise tolerance in a communications system. That is, turbo coding allows communications at E
b
/N
0
levels that were previously unacceptable using the existing forward error correction techniques.
Many systems use forward error correction techniques, and therefore would benefit from the use of turbo coding. For example, turbo codes could improve the performance of wireless satellite links where the limited downlink transmit power of the satellite necessitates receiver systems that can operate at low E
b
/N
0
levels. Using turbo codes in a wireless satellite link could reduce the dish size for a digital video broadcast (DVB) system, or alternatively, allow more data to be transmitted.
Digital wireless telecommunication systems such as digital cellular and PCS telephone systems also use forward error correction. For example, the IS-95 over-the-air interface standard, and its derivatives, such as IS-95B, define a digital wireless communications system that uses convolutional encoding to provide coding gain to increase the capacity of the system. A system and method for processing RF signals substantially in accordance with the use of the IS-95 standard is described in U.S. Pat. No. 5,103,459 entitled “System and Method for Generating Signal Waveforms in a CDMA Cellular Telephone System” assigned to the assignee of the present invention and incorporated herein by reference ('459 patent).
Many types of turbo coding require more complex circuitry than the previous available FEC coding techniques. For example, many turbo codes use maximum a posteriori probability (MAP) decoders, which are more complex than conventional Viterbi trellis decoders. For high data rate applications, the more complex MAP decoder can reduce the data rate at which data transmission can be performed. Thus, it would be highly desirable to have a MAP decoder that could operate at high data rates.
SUMMARY OF THE INVENTION
The present invention is a novel and improved technique for performing maximum a posteriori probability (MAP) decoding, with particular application to turbo, or iterative, coding techniques. In accordance with one embodiment of the invention, a set MAP decoders are applied in parallel to different sections of a frame symbol estimates to be decoded. Each MAP decoder generates decisions for the section of symbol estimates received. In one embodiment, initialization values are generated. The MAP decoders use the initialization values to start decoding at each section where the section begin at the middle of the frame.
REFERENCES:
patent: 5544328 (1996-08-01), Seshadri
patent: 5721745 (1998-02-01), Hladik et al.
patent: 6192503 (2001-02-01), Chennakesku et al.
patent: 6343368 (2002-01-01), Lerzer
patent: 9820617 (1998-05-01), None
Dawid, et al., “Map Channel Decoding: Algorithm and VLSI Architecture”, VLSI Signal Processing, Proceedings IEEE wol 6, No. VI, Oct. 1993, pps. 141-149.
Benedetto, et al., “Soft-Output Decoding Algorithms for Continuous Decoding of Parallel Concatenated Convolutional Codes”, IEEE International conference on Communications, Jun. 1996, pps 112-117.
Hsu, et al., “A Parallel Decoding Scheme for Turbo Codes”, IEEE International Symposium on Circuits and Systems, May 1998, pps. 445-448.
Brown Charles D.
Burd Kevin M
Cheatham Kevin T.
Qualcomm Incorporated
Tran Khai
LandOfFree
Highly parallel map decoder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Highly parallel map decoder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Highly parallel map decoder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3358857