An NAK-based hierarchical ARQ scheme for reliable data multicast in integrated communication and broadcast networks

In this paper we propose a hierarchical architecture of the return channel in ICBN and an NAK-based hierarchical ARQ scheme (H-ARQ). The H-ARQ scheme can alleviate the NAK implosion and balance the retransmission traffic between broadcast and communication networks. The users are divided into regions in the communication network, and each region has a Local Recovery Router (LRR), which cooperates with the Data Broadcast Server (DBS) to decide the retransmission method. The impact of the ARQ scheme on the data broadcast performance is analyzed, and the NAK arrivals in ICBN are modeled and simulated.We also propose an algorithm to optimize the parameters and cost functions in the H-ARQ scheme. At last we give some simulation results to validate the improvement of the H-ARQ scheme running on the hierarchical system architecture.