Distributed Turbo Coding with Information Transfer via Timing of the Half-Duplex Relay-Phases

We consider a wireless half-duplex relay communication from a source to a destination with a distributed turbo code. The source broadcasts code-bits to relay and destination during the relay-receive phases, the relay decodes and transmits additional code-bits to the destination during the relay-transmit phases. We propose to use the timing of the relay-receive and relay-transmit phases to transfer more additional code-bits to the destination at the cost of stricter synchronization requirements. Moreover, it is required that the relay is able to switch its state rapidly between receiving and transmitting from symbol to symbol. The destination does not know the timing of the relay-receive and relay-transmit phases a priori and has to distinguish the transmissions of source and relay due to the received amplitude. The received amplitude at the destination is higher for transmissions of the relay because the relay-destination link is stronger than the source-destination link. A constant- weight code is used to determine the timing of the relay-receive and relay-transmit phases. Simulation results for an example show a substantial gain of the proposed extension.