Application Layer Forward Error Correction for Mobile Multimedia Broadcasting
Application Layer Forward Error Correction (AL-FEC) is an innovative way to provide reliability in mobile broadcast systems. Conventional data such as multimedia files or multimedia streams are extended with repair information which can be used to recover lost data at the receiver. AL-FEC is integrated into content delivery protocols (CDPs) to support reliable delivery. Several standardization committees such as 3GPP and DVB have recognized the importance of AL-FEC and have standardized Raptor codes as the most powerful FEC codes to be used for such applications. The major characteristics of Raptor codes are channel efficiency, low-complexity, and flexibility. An important consideration when using application layer codes is system integration. With the right system design including AL-FEC, the efficiency and/or quality of delivery services can be significantly enhanced. This work shows these benefits in selected use cases, specifically focussing on 3G based multimedia broadcasting within the MBMS standard.