LDPC Transmitter Shortening Layout for BER and FER Improvement
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Solution Overview
Problem
Current digital broadcasting systems face challenges in providing improved performance, particularly in terms of bit error rate (BER) and frame error rate (FER), due to limitations in signal transmission and reception methods.
Innovation Solution
A transmitter is designed with an outer encoder, zero padder, and LDPC encoder to encode input bits, pad zero bits based on a predetermined shortening pattern, and divide LDPC information bits into bit groups to improve BER and FER performance, using specific equations and tables to determine the number and placement of padded bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encoding methods are used, then device complexity is reduced, but bit error rate and frame error rate performance deteriorate
Solution Approach 1:
The LDPC information bits are divided into multiple bit groups (e.g., 9 groups of 360 bits each). Zero bits are selectively padded to specific bit groups based on a predetermined shortening pattern rather than uniformly across all groups. This segmentation allows the system to achieve better BER/FER performance through strategic positioning of information bits while maintaining manageable device complexity through structured organization.
Solution Approach 2:
Different bit groups are treated differently through selective zero padding. The shortening pattern determines which specific bit groups receive zero bits based on their position and content characteristics. This local differentiation optimizes error performance by ensuring information bits are positioned in locations with better error protection characteristics, rather than applying a uniform encoding approach throughout.
2Reliability
If zero bits are padded to improve BER and FER performance, then transmission reliability is improved, but signal transmission complexity increases
Solution Approach 1:
The zero padding is performed in advance during the encoding stage, before transmission. The shortening pattern is predetermined and stored in both transmitter and receiver. This preliminary action allows the receiver to correctly interpret the transmitted signal structure without requiring complex real-time analysis, thereby improving reliability while keeping transmission complexity manageable through pre-planned bit positioning.
Solution Approach 2:
The system changes the parameter of bit group composition by selectively adding zero bits to specific groups based on the shortening pattern. This parameter modification (changing which groups are full and which are shortened) optimizes the error performance characteristics of the transmitted signal without fundamentally changing the overall encoding architecture.
Data Source
AI summary
A transmitter is provided. The transmitter includes: an outer encoder configured to encode input bits to generate outer-encoded bits including the input bits and parity bits; a zero padder configured to constitute Low Density Parity Check (LDPC) information bits including the outer-encoded bits and zero bits; and an LDPC encoder configured to encode the LDPC information bits, wherein the LDPC information bits are divided into a plurality of bit groups, and wherein the zero padder pads zero bits to at least some of the plurality of bit groups, each of which is formed of a same number of bits, to constitute the LDPC information bits based on a predetermined shortening pattern which provides that the some of the plurality of bit groups are not sequentially disposed in the LDPC information bits.