Two-Hop Relay-Systems with OFDM-IDM Space-Time Coding

In mobile communication systems pathloss and shadowing are two of the main limiting factors. In order to overcome these effects, relaying has been identified as a very promissing technique. In relay-systems additional nodes are introduced to the system, which are neither source nor destination of transmissions themselves. Instead their task is to support existing transmissions and thereby effectively increase the system’s reliability. Besides a reduction of the pathloss due to smaller distances between nodes, relays also offer diversity gains which can increase the robustness of the overall system. In order to exploit the offered spatial diversity, Space-Time Codes (STC) have shown to be a very flexible scheme.