Abstract With the growing popularity of mobile broadband by using smart phones, laptops, notebooks etc., High Speed Packet Access (HSPA) has raised to one of the fastest growing mobile broadband technologies in different markets. The Third Generation Partnership Project (3GPP) has included HSPA in Release 5 and Release 6 for downlink and for uplink. The continued evolution of HSPA, the Multi-Carrier High Speed Download Packet Access (HSDPA) was introduced in Release 8. The Multi-Carrier HSDPA evolution improves the end user performance and user throughput by lower latency, low power consumption, low cost and increases the peak data rates per user. Hence, Single-Carrier HSDPA capacity was sufficient to meet the user requirements but now the rapidly growing subscriber took place due to several factors like better user experience for broadband multimedia application, high speed internet and cost effective service. The main focus of this thesis is the Multi-Carrier HSDPA evolution and its implications on network architecture and user equipment and evaluates its achievable user throughput performance (with focus on downlink) compare with the Single-Carrier HSDPA. Two types of simulation models are developed and applied. The first model is a queuing system model where data arrives to the system according to a Poisson process. The second model is a link level simulation model which is basically a software implementation of one or multiple links between the evolved base station (eNodeB) and the User Equipments (UEs), with a channel model to reflect the actual transmission of the waveforms generated. Both simulation models results show that the throughput of Multi-Carrier HSDPA is twice compare with the Single-Carrier HSDPA