Mobility management and eICIC in LTE femtocells

University of Technology Sydney. Faculty of Engineering and Information Technology.LTE-Long Term Evolution was proposed in Release 8 by Third Generation Partnership Project (3GPP) with a new Radio Access Network (RAN) and an Evolved Packet Core (EPC) Network to provide a smooth migration to 4G network. The number of mobile subscribers and data usage have increased exponentially since the roll-out of LTE because of new higher capacity LTE air-interface. This has created new challenges for the network operators to provide a satisfactory quality of service to the mobile users especially in indoor scenarios. One solution to provide better indoor user experience in a cost effective manner is use of femtocells which were introduced in 3GPP LTE, Release 8. Femtocells are short ranged indoor small cells, which share the same spectrum with macrocell and could have a limited user access. Higher data rate, improved indoor coverage, QoS and longer battery life could be achieved with the deployment of femtocells. Nonetheless, the plug-and-play capability and lower cost of these small cells pose huge interference problems in uplink and downlink when installed in dense urban areas and in an unplanned way. Interference management and handover are two important factors to be considered while implementing LTE network with femtocells. The use of hard handover in 3GPP LTE and LTE-A systems coupled with the absence of a direct signaling interface between macrocell and femtocell may cause call drops and delay in mobility management. The objective of this research is to address the challenges posed by handover performance and interference mitigation in LTE system with femtocells. In this work, a speed based handover algorithm is proposed, simulated in LTE-SIM and optimized by introducing Almost Blank Sub-Frames (ABSF) and Cell Range Expansion (CRE) interference coordination schemes. Simulation results show that, better user experience can be achieved in terms of delay, fairness, reduced number of call-drops while maximizing the throughput

GROUP BASED ALGORITHM TO MANAGE ACCESS TECHNIQUE IN THE VEHICULAR NETWORKING TO REDUCE PREAMBLE ID COLLISION AND IMPROVE RACH ALLOCATION IN ITS

ABSTRACT Intelligent transportation system (ITS) is an application which provides intelligence to the transportation and traffic management systems. Although the word ITS applies to all systems in the transportation but as per the European union directive it is the application of Information and communication technology in the field of transportation is defined as ITS. The communication technology has evolved greatly today from 2G/3G to long term evolution (LTE). In this paper we focus on the LTE and its application in the ITS. Since LTE offers excellent QoS, wide area coverage and high availability it is a preferred choice for vehicle to infrastructure (V2I) service. At the same time the LTE customer base is increasing day by day which results in congestion and accessing the network to send or request resources becomes difficult. In this paper we have proposed a group based node selection algorithm to reduce the preamble ID collision otherwise this uncoordinated preamble ID transmission by vehicle node (VN) will eventually clog the network and there will be a massive congestion and re-transmissions attempts by VNs to obtain the random access channel (RACH). KEYWORDS Intelligent transportation system (ITS), Long term evolution (LTE), Mobile ad hoc network (MANET), Vehicle ad hoc network (VANET), Vehicle to infrastructure (V2I), Vehicle to vehicle (V2V), Random access channel (RACH)

SURVEY OF LTE DOWNLINK SCHEDULERS ALGORITHMS IN OPEN ACCESS SIMULATION TOOLS NS-3 AND LTE-SIM

ABSTRACT The LTE/LTE- KEYWORDS Round robin (RR), Proportional fair (PF), Maximum throughput scheduler (MT), Throughput to average scheduler (TTA), Blind equal throughput scheduler (BET), Token bank fair queue scheduler (TBFQ), Priority set scheduler (PS)