  We present an analysis on the production of two same-sign lepton pairs at the
LHC, mediated by bileptons in the $SU(3)_c\times SU(3)_L\times U(1)_X$ theory,
the so-called 331 model. Compared to other 331 scenarios, in this model the
embedding of the hypercharge is obtained with the addition of 3 exotic quarks
and doubly-charged vector gauge bosons with lepton numbers $\pm 2$ in the
spectrum ($Y^{\pm\pm}$), which can mediate the production of four-lepton final
states. Furthermore, a complete description of the model requires the
introduction of a Higgs scalar sector, which is a sextet of $SU(3)_L$,
necessary in order to correctly account for the lepton masses. As a result of
this, new doubly-charged scalar states $H^{\pm\pm}$ are part of the spectrum as
well and can in principle compete with the vector bileptons in giving rise to
four-lepton final states. We investigate both channels and study several
observables at the LHC, for both signal and Standard Model $ZZ$ background.
With respect to previous work on vector- and scalar-bilepton production, we use
the most updated exclusion limits at the LHC and implement the 331 model in a
full Monte Carlo simulation code, capable of being interfaced with any analysis
framework. Our result is that the 331 signal can be discriminated from the
background with a significance of 6-9 standard deviations, depending on the LHC
luminosity, with the vector bileptons dominating over the scalar ones.
