  In this letter, the performance of multiuser-radio frequency/free space
optics (RF/FSO) two-way relay network in the presence of interference is
investigated. The FSO link accounts for pointing errors and both types of
detection techniques, i.e. intensity modulation/direct detection as well as
coherent demodulation, which is modeled as double generalized gamma (D-GG)
turbulence channel. On the other hand, the multiple users on the RF link are
assumed to undergo Nakagami-m fading. Multiple co-channel interferers (CCIs)
which corrupt the signal at relay node are modeled using Nakagami-m
distribution. Specifically, the exact closed-form expressions for the outage
probability (OP) of the overall system is derived. Moreover, the closed form
expression for the achievable sum-rate (ASR) of the considered system is
presented. In order to simplify the results,the asymptotic approximations of
the OP and ASR are derived in terms of elementary functions. The results
presented in the paper are validated by Monte-Carlo simulations.
