Decentralized Wireless Networks With Asynchronous Users and Burst Transmissions

This paper studies a decentralized wireless network of asynchronous transmitter-receiver pairs with burst transmissions. Each receiver learns about the number of active users, channel coefficients, and mutual delays based on locally available measurements. The estimates for the mutual delays are not perfect, however, they are reliable enough to guarantee successful decoding. Two signalling schemes are addressed, namely, randomized masking (RM) and reduced cycle transmission (RCT). Under RM, the n symbols of a codeword are generated according to a Bernoulli-Gaussian distribution with activity factor 0 <; θ ≤ 1. This is in contrast to RCT where each codeword consists of ⌈θn⌉ Gaussian symbols followed by n-⌈θn⌉ zeros. Assuming the transmitters are unaware of the number of users, channel coefficients, and mutual delays, the probability of outage under RM is considerably lower compared with RCT if the signal-to-noise ratio (SNR) is sufficiently large. A generalized RCT scheme is also examined where the n - ⌈θn⌉ zero symbols are not necessarily located at the end of a codeword. In the asymptote of large SNR, the outage probability becomes vanishingly small under RM, however, it is bounded away from zero for generalized RCT regardless of the value of SNR.