Performance of Multi-Carrier Waveforms in Vehicle-to-Vehicle Communications

Future 5G systems are expected to address a much wider range of scenarios than current mobile communications systems. Vehicle-to-vehicle (V2V) communications is anticipated as one of key future services and it imposes challenging requirements on the air interface such as supporting high mobility and asynchronous multiple access. These requirements may not be best addressed by the currently applied waveforms such as Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM). This paper discusses the design and performance tradeoffs of two waveform families frequently discussed in the literature targeting 5G: filter bank multi-carrier with offset quadrature amplitude modulation (FBMC/OQAM) and filtered OFDM (F-OFDM) with specific focus on V2V communications by utilizing a realistic geometry-based stochastic V2V channel model. F-OFDM approaches inherit good properties of CP-OFDM and we show considerable gains as compared to CP-OFDM in asynchronous V2V transmissions due to low out-of-band (OOB) radiation achieved by additional per-subband filtering. The typically long filter for FBMC/OQAM leads to low efficiency for short bursts and the use of OQAM makes it non-trivial to adapt certain schemes well-developed for CP-OFDM. However, we show that FBMC/OQAM outperforms F-OFDM approaches in some severe V2V scenarios thanks to even lower OOB radiation by persubcarrier filtering.