Discontinuous Reception (DRX) is proposed as one of key solutions to conserve the battery power of User Equipment(UE)in 3GPP Long Term Evolution (3GPP LTE). This thesis report has evaluated different DRX parameter settings for VoIP traffic both in uplink and downlink and found out different gains in terms of power saving and network performance. It is shown that key parameters include On-duration Timer, Inactivity Timer and length of DRX cycle. These three parameters have major impact on both VoIP performance and power saving in UE. Different combinations of these three parameters show different results.