Performance Tradeoffs of Vector Orthogonal Chirp Division Multiplexing

In this letter, we investigate the performance tradeoffs of vector orthogonal chirp division multiplexing (VOCDM) transmissions over doubly selective channels. The VOCDM modulation is implemented by performing M parallel N-size inverse discrete Fresnel transforms (IDFnTs). Based on the complex exponential basis expansion model (CE-BEM) for doubly selective channels, we derive the VOCDM input-output relationship, and show performance tradeoffs of VOCDM with respect to (w.r.t.) its modulation parameters M and N. To be more specific, we analyze the diversity and peak-to-average power ratio (PAPR) of VOCDM w.r.t. M and N. Under doubly selective channels, VOCDM exhibits superior diversity performance as long as the parameters M and N are configured to satisfy some constraints from the delay and the Doppler spreads of the channel, respectively. The PAPR of VOCDM signals decreases as N decreases. With small values of N, VOCDM signals exhibit significantly lower PAPR compared with its multi-carrier counterparts. These theoretical findings are verified through numerical simulations.