In wireless communication, source and destination nodes communicate with each other when they are within their transmission range. In network condition where the source and destination nodes are out of transmission range and are not able to perform successful communication, relay nodes are used for successful communication. The network that consists of source node,destination node and relay node(s) is called as relay network. There are different relaying schemes available to handle the relay. The conventional popular relaying schemes are Amplify and Forward (AaF) and Decode and Forward (DaF).
Raptor Q is the systematic fountain code and most advanced forward error correction (FEC) codes for data networks. Raptor Q is used in relay network for recovering the lost source packets. If the communication between source and destination node is successful such that destination node receive at least the minimum number of packets required by Raptor Q to perform successful decoding.In this case relay node is not needed. While in bad channel condition between source and destination node, relay network is used to assist Raptor Q to perform successful decoding. However when using relaying schemes like AaF, we have the problem of duplicity or ambiguity of packets in the destination node. As packets are received from both source and relay, there is a high probability of having duplicated packets. Duplicity affects the failure distribution of Raptor Q and the failure distribution affects the quality of service.
In this thesis, we propose a novel relaying scheme for relay network. The proposed scheme is “Simply Merge and Forward” (SMaF) which merge packets in relay node and forward them to client as new parity packets. These parity packets are used by Raptor Q to regenerate the lost source packets in a destination. In the conventional relaying scheme like Amplify and Forward (AaF), there is a higher probability of duplicate packets in a destination. This affects the failure distribution of Raptor Q and deteriorate the quality of service. The cooperative communication between server and relay node is done by time sharing.
Simulation results show that SMaF reduces the duplicity and provide better failure distribution and quality of service than AaF.