Regional Engineering Postgraduate Conference (EPC) 2011 IMPLEMENTATION OF NEW TCP CONGESTION CONTROL MECHANISM OVER LONG TERM EVOLUTION ADVANCED NETWORKS Ghassan A. Abed, Mahamod Ismail and Kasmiran Jumari Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia, Malaysia ABSTRACT Long Term Evolution-Advanced (LTE-Advanced) should be real broadband wireless network that provides peak data rates equal to or greater than those for wired networks. The major high-level requirements of LTE-Advanced are reduced network cost (cost per bit), better service provisioning and compatibility with 3GPP systems. This paper presents a new mechanism to improve the performance of Congestion Window (cwnd) by using a new mechanism that supports bandwidth estimation to detect the capacity of network path. That will enhance the TCP ability to send a large possible amount of packets from source to destination through LTE-Advanced model by using Network Simulator NS-2. The new algorithm through simulation and modeling experiments and from the obtained results achieves the required congestion window with high efficiency. Keywords: TCP, congestion control, LTE, LTE-Advanced. INTRODUCTION As the development of LTE, LTE-Advanced must be compatible backwards in the sense that it should be possible to deploy LTE-Advanced spectrum already occupied LTE with no effect on existing plants LTE, to include the possibility for data rates of up peak to 1 Gigabit per second in the downlink and 500 Mbps in uplink (Parkvall et al., 2008). However, more important than the peak data rates is the possibility of providing high data rates over the greater part of the cell. While LTE Rel.8 supports peak data rates exceeding 300 Mbps in the downlink (DL) and 75Mbps in the uplink (UL), LTE is expected to provide advanced Rel.10 up to 1Gbps in megabits per second and DL 500 UL in environments in the navigation low (Bou Saleh et al., 2010). When using TCP over the cellular infrastructure, and the result is that both times the end-to-end production and use of radio link is very weak. This is because the dynamic characteristics of TCP and wireless connections do not fit well together (Möller et al., 2005). TCP limits its sending rate by controlling the congestion window (cwnd) size, which is the number of packets that may be transmitted in a flow. The time between delivering a packet and receiving its ACK is a round-trip time (RTT). A TCP sender can send up to the cwnd size of packets during one RTT. Therefore, the average rate of a TCP over one RTT is roughly the window size divided by the RTT (Choi et al., 2006).