The Turbo-Fountain and its Application to Reliable Wireless Broadcast

Reliable wireless broadcast with asynchronous data access based on fountain coding is investigated. We review the traditional problem formalization for fountain codes operating on erasure channels and we generalize the problem formalization to arbitrary types of channels. We introduce a novel type of rateless codes based on the turbo principle: the Turbo-Fountain. The Turbo- Fountain is able to consider soft information from the channel in the decoding process. Two realizations for the Turbo-Fountain are introduced. We show simulation results for the Turbo-Fountain realizations on the AWGNand on fading channels. Additionally, we compare the achievable Turbo-Fountain performance with traditional fountain codes designed for the erasure channel, both on the AWGN and on fading channels, considering appropriate erasure declaration. It is shown that the Turbo-Fountain provides significant performance gains, due to exploitation of soft information, and approaches capacity.