Effective OFDMA Based Signaling in Ad-Hoc Wireless Networks

Ad hoc wireless networks without central authority have attracted much attention in both academic society and industry. A key aspect of communications in such networks is the large dynamic range of interference. OFDMA (multiplexing simultaneous transmissions in different frequency tones) is an effective way of dealing with interference. On the other hand, there are many known distortions in transmit and receive chains of the communication devices, e.g. non linearity of the power amplifier, which can compromise the OFDMA orthogonality among the resources assigned to different transmissions. These distortions, together with the large dynamic range one would expect in ad hoc communications, can pose a threat to the effectiveness of communications in OFDMA ad hoc networks. In this paper, we propose and evaluate different signaling choices for communications in ad hoc networks, via both analysis and simulations. In particular, we observe that OFDMA based single tone signaling, i.e. each user transmits only on a single frequency tone, outperforms other signaling choices in many aspects.