Interference Analysis Of Coexistence Between Femtocells And TD-SCDMA HSDPA

TD-SCDMA is the time division-synchronous code division multiple access (TDD-CDMA) specification for the third generation (3G) mobile communication, which is proposed by China Wireless Telecommunication Standard Group. TD-SCDMA has the advantage in supporting flexible services and spectral efficiency. Besides the traditional voice services, data services are expected to have significant growth over the next few years. In order to meet the increasing demand for high data-rate services, high speed downlink packet access (HSDPA) is an enhancement solution proposed by 3GPP, which is available for TD-SCDMA system. The adaptive modulation and coding (AMC), hybrid automatic repeat request (HARQ) and fast packet scheduling are the key techniques.Femtocell also called the Home NodeB, is a small base station with the development of the three generation network, which provides the network access point, low-power consumption and the signal coverage in indoor environment. Since now, lots of contributions have been done to investigate the system performance of deploying Femtocells in WCDMA HSDPA and UMTS/HSPA+ network, including the interference management techniques, the coverage situation and the capacity analysis. However, there are few studies focusing on the femtocells deploying in TD-SCDMA HSDPA network. In this paper, the co-channel deployment of femtocells in TD-SCDMA HSDPA network is considered. The interference of Femtocells and the capacity performance are mainly focused.The interference between the macro-cells and the Femtocells is studied by the dynamic system level simulation using the Matlab platform, which is based on the time-driven and to simulate the random trajectory of an UE. Moreover, the channel estimation, the adaptive modulation and coding (AMC), packet scheduling and hybrid automatic repeat request (HARQ) are implemented. The modules of the simulation platform are as the following:(1)User mobile module(2) User channel generation module(3) Channel estimation(4) Adaptive modulation and coding (including the assignment of the code resources)(5) Packet scheduling module(6) Data rate mapping (including the HARQ)(7) Collect the statistics moduleIn this paper, the results related to the system performance are provided, which can give a solid foundation for evaluating the dynamic simulation platform. Then the interferences towards the users in the macro-cells are studied according the different scenarios setting on Femtocells. These studies are demonstrated the interferences of Femtocells and the capacity performance of the macro cells. Compared to adopting the fixed power scheme for Femtocells, the benefits of the adaptive power mechanism are demonstrated to flexibly configure the HNB powers and to reduce the interferences on the system performance of macro cells.