Due to the frequency reuse

the outage performance of the interference-limited two-hop multiple access-channel (TH-MAC) has become one of the problems to be solved.With interference-limited destination

the outage probability of the amplify-and-forward (AF) TH-MAC is derived in closed form.Firstly

the outage probability is divided into two parts:one is the probability that an outage happens at the relay;the other is the probability that outage does not happen at the relay

but happens at the destination.Then

based on rational approximation for the second part of the outage probability

a closed form outage probability is derived for the channel

and it provides a theoretical framework for the practical system design.Numerical results show that the approximation fits well with the Monte Carlo results

which validates the accuracy of the approximation.