Hybrid ARQ Based on Serially Concatenated Block Codes Using Iterative Decoding for Real-Time Communication

* This work is funded by the national Swedish Real-Time Systems research initiative ARTES (www.artes.uu.se), supported by the Swedish Foundation for Strategic Research. Abstract A protocol for real-time communication over a wireless channel, based on concatenated codes using iterative decoding is proposed. The concept of deadline dependent coding (DDC), previously suggested by the authors, to maximize the probability of delivering the information before a given deadline, is further developed to include concatenated codes. The strategy of DDC is to combine different coding and decoding methods with automatic repeat request (ARQ) in order to fulfill the application requirements. These requirements are formulated as two Quality of Service (QoS) parameters: deadline (tDL) and probability of correct delivery before the deadline (Pd), leading to a probabilistic view of real-time communication. An application can negotiate these QoS parameters with the DDC protocol, thus creating a flexible and reliable scheme.