Relay Position Considering Interference from Other Sub-Channels in D2D Group-casting Systems

Device-to-device (D2D) communication is a way to communicate directly between devices without going through the base station or other infrastructure. In many D2D communication systems, orthogonal frequency division multiple access (OFDMA) is used in order to maintain the similarity with the mobile communication systems and to secure a sufficient transmission distance. In OFDMA systems, sub-channels, consisting of multiple subcarriers, are used to concurrently support multiple users. Although sub-channels in OFDMA systems are theoretically orthogonal, there is non-negligible interference from other sub-channels due to in-band emission. This paper considers a D2D group-casting system with a relay focusing on the effect of the interference from other subchannels, and calculates the outage probabilities according to the relay position.