sentences:  Similar to fixed relays, mobile relays can enlarge the coverage area, reduce the overall transmit power, and/or increase the capacity at cell edges.On the other hand, due to their opportunistic nature, mobile relays are less reliable than fixed relays since the network topology is highly dynamic and unstable.The mobile user relays enable distributed MSs to self-organize into a wireless ad hoc network, which complements the cellular network infrastructure using multi-hop transmissions.