이동형 DVB-S2 기반 최적의 상위계층 부호화 방식에 관한 연구

Abstract

Efficient support for digital broadcasting (DVB) services in mobile systems is crucial for mobile operators and broadcasters. Several DVB systems are currently in development internationally, to meet these challenges, and there have been several competing standards proposed (T-DMB, DVB-H, S-DMB) with different characteristics and performance. DVB-H(Digital Video Broadcasting for Handhelds terminal) is a relatively new data broadcasting standard that enables delivery of various Internet Protocol(IP) based services to mobile receivers. The DVB-H standard, which is based on and compatible with DVB-T(DVB-Terrestrial), introduces a solution to problems caused by mobility and a long-term fading channel. The DVB-H standard, MPE-FEC (Multi-Protocol Encapsulation-Forward Error Correction), includes Reed Solomon (RS), combined with virtual interleaving, to compensate for a long-term fading environment. The DVB-T physical layer also consists of an additional in-depth interleaver that serves as a block and time interleaver, to compensate for a long-term fading channel.

In this thesis, we described DVB-S2 system for mobility. Cross layer coding technique are needed to maintain the performance in deep fading channel. Cross layer coding is divided into two kinds of level. First level is Physical layer coding and, second layer is link layer or upper layer coding. Fixed on DVB-S2 short frame coding method as a physical layer, this thesis shows the simulation results for various coding method as an upper layer coding. Furthermore, for research on optimal cross layer coding method, this paper analyzed the performance of each coding method on according to mobile vehicle speed, data rate, interleaving memory size, and IP packet size.

From the simulation results, perfect frame synchronization was assumed, as well as perfect symbol timing recovery, and this thesis summarized the important results. First, the most important result was that virtual interleaving is a crucial component for improving the performance in a long-term fading channel. This thesis confirmed that the performance is improved by increasing the virtual interleaving size and train speed. Second, this thesis concluded that the larger the virtual interleaving size, the greater the range of data rates provided, and the smaller the IP packet size, the better the performance.