| Summary: | 碩士 === 國立中央大學 === 通訊工程學系 === 104 === Chinese Digital Terrestrial Multimedia Broadcast (DTMB), Previously known as DMB-T/H (Digital Multimedia Broadcast-Terrestrial/Handheld), has now been listed as one of the official international DTTB (Digital Terrestrial Television Broadcasting) Standard. Use time-domain synchronous orthogonal frequency division multiplexing modulation technique (TDS-OFDM), which is characterized by using PN sequence as guard interval, having the ability to achieve fast synchronization and channel estimation. In the frame body (FB) there are two kinds of modulation mode, single-carrier and multi-carrier in which a single carrier modulation and frequency domain equalization method (SC-FDE) has raised for discussion in the past few years, this traditional architecture has a lower peak-to-peak ratio (PAPR) and less sensitive to the phase error, which is suitable for applications such as HDTV broadcasting or underwater communications system, but it cannot be against the frequency doubly selective channel.
In this paper, we discuss the channel estimation and equalization for the single-carrier specification signal, using PN595 as a guard interval. Channel estimation mainly dependent on the PN sequence, after its removed and the system is equivalent to the ZP-OFDM and compatible to its equalization algorithm. And we consider more practical situation to improve simulation accuracy by using upsampling, at the same time channel delay time is not on integer symbol period time, and there has sidelobe effect by the pulse-shaping filter which is resulting from the channel fractional delay after sampling at the receiver, will affect system performance.
Therefore we compare different channel estimation and equalization algorithms for particular channel model represented different classic situation and design the receiver, using computer simulation and observation of details, hope to adjust the parameters to achieve the effect of reducing the complexity and improve performance.
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