Cooperative communication has been recently applied to LTE networks to enable coverage extension and enhance link reliability through distributed spatial diversity. The error performance of a cooperative diversity system having two cooperating mobile users (designated as source and relay) and a destination has been analyzed. In this paper, the relay cooperates with the source through the amplify and forward protocol to enable the transmission of data from the source to the destination in a flat Rayleigh fading environment. A mathematical framework for the asymptotic analysis of this system in generic noise and interference and also the investigation of the performance of cooperative relaying over fading channel for an LTE downlink session has been done. Results show the exact Signal to Noise Ratio(SNR) and Symbol Error Rate(SER) analysis using QPSK and 4-QAM modulation schemes for direct link (source to destination) and relay link with maximal-ratio combining (MRC) at the receiver. © 2015 IEEE.