• Journal of Communications and Networks
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• v.15 no.5
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• pp.496-503
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• 2013

In an orthogonal frequency division multiplexing system, conventional interpolation techniques cannot correctly balance performance and overhead when estimating dynamic long-delay channels in single frequency networks (SFNs). In this study, classical filter analysis and design methods are employed to derive a complex interpolator for maximizing the resistible echo delay in a channel estimator on the basis of the correlation between frequency domain interpolating and time domain windowing. The coefficient computation of the complex interpolator requires a key parameter, i.e., channel length, which is obtained in the frequency domain with a tentative estimation scheme having low implementation complexity. The proposed complex adaptive interpolator is verified in a simulated digital video broadcasting for terrestrial/handheld receiver. The simulation results indicate that the designed channel estimator can not only handle SFN echoes with more than $200{\mu}s$ delay but also achieve a bit-error rate performance close to the optimum minimum mean square error method, which significantly outperforms conventional channel estimation methods, while preserving a low implementation cost in a short-delay channel.

• The Journal of the Korea Contents Association
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• v.14 no.5
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• pp.30-43
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• 2014

The number of online video content distributors are rapidly increasing in N-screen environment. The purpose of this study is to analyze the business model of these distributors, especially Netflix and Hulu. Basis on STOF model, environmental domain, service domain, organization domain and financial domain of each company are analyzed and compared. This study finds that each company's business model had distinct characters in earlier stage. Netflix offered online and offline service in low cost, while Hulu offered up-to-date TV contents without fees. However, two companies' business models are getting similar. The result of this study shows that highly competitive environment and increasing content budget affect two companies to adopt similar business model to survive.