Digital Broadcasting Receiver Switching VSB and OFDM Modes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Vestigial Sideband (VSB) transmission mode used in digital broadcasting in North America and Korea is prone to performance deterioration in poor channel environments, especially with portable and mobile receivers, requiring enhanced resistance to channel changes and noise.
Innovation Solution
A digital broadcasting system comprising a receiving unit, signaling decoder, SI handler, main and mobile service data processors, controller, and output controller that detects FIC signaling data, acquires channel configuration, performs demodulation and error-correction, and automatically switches between main and mobile services based on receiving environment, using retransmission channel information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If VSB transmission mode is used for digital broadcasting, then the system can provide main service with single carrier method, but the receiving performance deteriorates in poor channel environment and mobile conditions
Solution Approach 1:
The transmission system is segmented into two independent modes: main service using VSB single carrier method and mobile service using OFDM multi-carrier method. The receiving system can selectively activate appropriate processing paths based on service type, allowing simultaneous support of both transmission modes without compromising either service quality
Solution Approach 2:
The receiving system dynamically switches between VSB and OFDM processing modes based on the received service type indication. The controller activates or deactivates specific functional blocks (VSB demodulator, OFDM demodulator, error correction decoders) according to whether main service or mobile service is being received, optimizing performance for the current channel conditions
2Device complexity
If VSB transmission mode is used, then the system structure can be simplified, but resistance to channel changes and noise is insufficient for portable and mobile receivers
Solution Approach 1:
The receiving system is designed with universal functionality to handle both VSB and OFDM transmission modes through a single integrated architecture. It includes both VSB and OFDM demodulators, multiple error correction decoders (RS and LDPC), and a controller that selectively activates appropriate processing paths, enabling the same receiver to optimally process both main service and mobile service signals
Data Source
AI summary
A broadcast transmitter and a method of processing broadcast data in the broadcast transmitter are disclosed. The method includes the steps of performing RS encoding and CRC encoding on mobile service data to build RS frames belonging to an ensemble, wherein each of the RS frames are mapped into data groups, wherein each of the data groups comprises known data sequences and a portion of FIC data including information for rapid mobile service acquisition, wherein the information for rapid mobile service acquisition includes transport stream identification information for identifying a mobile broadcast carrying a mobile service that includes the mobile service data and C/N indication information for indicating whether the FIC data are applicable to a current transmission frame or a next transmission frame, multiplexing data in the data groups and main service data, and transmitting a transmission frame including the multiplexed data.