Initial acquisition for MANET with simultaneous transmissions

As the next generation mobile ad hoc network (MANET) evolves to allow for multiple simultaneous transmissions within one-hop for higher spectral efficiency, the interferences from the peer nodes will pose a challenge to the initial acquisition in the MANET. In this paper, we propose a maximum likelihood (ML) method of initial acquisition of the preamble sequences. Simulations show that this proposed method is robust against the interferences. We also propose to use a pair of Zadoff-Chu (Z-C) sequences as the preamble. By exploiting the unique structure of the Z-C sequences, we can estimate both timing and frequency offsets through two fast Fourier transforms (FFT). The estimation of the channel response and the interference covariance is also obtained as a by-product. Simulation results verified that the presented method is efficient in interference suppression and may allow for dozens of simultaneous transmissions.