Broadcast Signal Frequency Interleaving for Mobile Reception
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Solution Overview
Problem
Current digital broadcast systems face challenges in data transmission efficiency, robustness, and flexibility, particularly in handling large amounts of data and ensuring reliable mobile reception.
Innovation Solution
The method involves encoding service data, time interleaving, mapping into OFDM symbols, frequency interleaving using a different interleaving-seed for each OFDM symbol pair, and modulating the data for transmission, allowing for multiple services to be transmitted through the same RF signal bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If digital broadcast signals transmit large amounts of video/audio data and additional data, then service quality and functionality are improved, but data transmission efficiency and network robustness deteriorate
Solution Approach 1:
The patent segments broadcast data into multiple data pipes (DPs), each carrying different types of data (video, audio, additional services). This segmentation allows independent optimization of transmission parameters for each data type, improving overall transmission efficiency while maintaining high data quantity capability.
Solution Approach 2:
The patent employs variable transmission parameters including different modulation schemes (QPSK, 16-QAM, 64-QAM), coding rates, and guard interval lengths adapted to channel conditions. This dynamic parameter adjustment optimizes transmission efficiency for large data volumes while maintaining robustness.
2Adaptability or versatility
If digital broadcast signals include various types of additional data, then service functionality is improved, but transmission robustness deteriorates
Solution Approach 1:
The patent separates different service types into distinct data pipes with dedicated transmission parameters. Critical services receive higher robustness through lower-order modulation and stronger coding, while non-critical additional services use higher-order modulation for efficiency, thus maintaining both versatility and robustness.
Solution Approach 2:
Different portions of the transmitted signal receive different levels of protection and modulation based on their importance. The patent applies local quality optimization by assigning appropriate modulation and coding schemes to each data pipe according to its service requirements.
3Reliability
If broadcast signals are optimized for fixed reception, then transmission quality is improved, but mobile reception capability deteriorates
Solution Approach 1:
The patent implements dynamic adaptation to channel conditions through variable modulation and coding schemes that adjust based on received signal quality. This allows the system to maintain high transmission quality for fixed reception while adapting to the more challenging mobile reception environment.
Solution Approach 2:
The system changes transmission parameters including modulation order, coding rate, and guard interval length based on detected channel conditions. This parameter adaptation enables the same broadcast signal to serve both fixed and mobile reception requirements effectively.
4Reliability
If single service is transmitted through dedicated bandwidth, then service quality is improved, but bandwidth utilization efficiency deteriorates
Solution Approach 1:
The patent merges multiple services and data types into a single integrated broadcast signal transmitted over the same RF bandwidth. Different data pipes carrying video, audio, and additional services are multiplexed together, achieving high bandwidth utilization while maintaining service quality through dedicated parameter optimization for each pipe.
Solution Approach 2:
The broadcast system is designed to transmit multiple services simultaneously through the same transmission medium. The data pipe structure enables universal bandwidth utilization where the same RF signal carries diverse services with different quality requirements.
Data Source
AI summary
A method and an apparatus for transmitting broadcast signals thereof are disclosed. The apparatus for transmitting broadcast signals comprises an encoder encoding service data, a time interleaver interleaving the encoded service data, a mapper mapping the interleaved service data into a plurality of OFDM (Orthogonal Frequency Division Multiplex) symbols to build at least one signal frame, a frequency interleaver interleaving data in the at least one signal frame by using a different interleaving-seed which is used for every OFDM symbol pair comprised of two sequential OFDM symbols, wherein the frequency interleaver calculates an interleaving address for the different interleaving-seed based on a main-PRBS sequence and a cyclic shifting value, a modulator modulating the frequency interleaved data by an OFDM scheme and a transmitter transmitting the broadcast signals having the modulated data, wherein an interleaving-seed is generated based on a cyclic shift value and an FFT size of the modulating.