Three-Segment Preamble Symbol for DVB-T2 Channel Estimation
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Solution Overview
Problem
The existing preamble symbol design in DVB_T2 standards fails in complex frequency selective fading channels, leading to performance degradation in coherent detection and differential decoding failures, especially in long multi-path channels.
Innovation Solution
A preamble symbol receiving method and device that utilize a combination of three-segment time-domain structures, including a time-domain main body signal, a prefix, and a postfix or hyper prefix, for enhanced timing synchronization and frequency offset estimation, allowing for coherent detection and improved channel estimation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a time-domain structure without cyclic prefix is used (as in DVB_T2 standard), then device complexity is reduced, but channel estimation performance deteriorates severely in frequency selective fading channels
Solution Approach 1:
The preamble symbol is divided into multiple segments including a cyclic prefix portion and a main body portion. The cyclic prefix segment is specifically designed to enable accurate channel estimation by providing a reference that correlates with the channel impulse response, while the main body contains data or additional synchronization information. This segmentation allows the system to maintain low complexity while improving channel estimation reliability through the dedicated cyclic prefix structure.
2Speed
If rough timing synchronization is used in long multi-path channels, then processing speed is improved, but frequency offset estimation accuracy deteriorates
Solution Approach 1:
The patent implements a two-stage synchronization approach where preliminary rough timing synchronization is performed first to quickly acquire approximate timing information, followed by refined timing and frequency offset estimation using the known cyclic prefix structure. The cyclic prefix provides a reliable reference for subsequent precise frequency offset estimation, allowing the system to achieve both speed and accuracy by performing actions in a predetermined sequence.
3Device complexity
If DBPSK differential decoding is used in complex frequency selective fading channels, then coherent detection complexity is reduced, but decoding reliability deteriorates
Solution Approach 1:
The cyclic prefix acts as an intermediary that enables accurate channel estimation, which in turn provides reliable channel state information for coherent detection. Instead of directly performing differential decoding on the received signal, the system uses the cyclic prefix to estimate the channel first, then uses this channel estimate to guide the detection process. This intermediary step of channel estimation through the cyclic prefix improves decoding reliability while keeping the overall complexity manageable.
Data Source
AI summary
Provided are a preamble symbol receiving method and device, characterizing in that the method comprises the following steps: processing a received signal; judging whether the processed signal obtained contains the preamble symbol desired to be received; and if a judgement result is yes, determining the position of the preamble symbol and resolving signalling information carried by the preamble symbol, wherein the received preamble symbol comprises at least one time-domain symbol generated by a transmitting end using a free combination of any number of first three-segment structures and/or second three-segment structures according to a predefined generation rule, the first three-segment structure containing: a time-domain main body signal, a prefix generated based on the entirety or a portion of the time-domain main body signal, and a postfix generated based on the entirety or a portion of a partial time-domain main body signal, and the second three segment structure containing: the time domain main body signal, a prefix generated based on the entirety or a portion of the time domain main body signal, and a hyper prefix generated based on the entirety or a portion of the partial time domain main body signal.