Design and development of the network interface, packets scheduling and interference mitigation schemes for LTE based femtocell networks / Sinan Ghassan Abid Ali Al-Nasir

Cellular networks face numerous challenges in providing services for indoor users.Therefore, femtocells are suggested as a solution to indoor coverage issues that macro cells have failed to address to date in cellular networks such as Global System for Mobile Communication (GSM), Universal Mobile Telecommunications System (UMTS), and Long Term Evolution (LTE). Although femtocells can provide various benefits for both operators and users, many technical challenges must be resolved for effective femtocell deployment in real environments. In this thesis, the network interface, the packet scheduling and the interference management challenges are investigated in order to address these issues with proper solutions. The network interface challenge is related to the integration of the femtocell in a cellular network such as LTE. The proposed solution is to deploy an IP Multimedia Subsystem (IMS) as an integration platform between the femtocell and the LTE cellular network. Thus, an IMS module has been implemented for signalling in a LTE-based femtocell network that contains both registration and invitation procedures. Based on this study, it has been observed that the integration of an IMS in a LTE based femtocell network can improve the network performance since the Packet Loss Ratio (PLR) can be minimised

Q-Learning vertical handover scheme in two-tier LTE-A networks

Global mobile communication necessitates improved capacity and proper quality assurance for services. To achieve these requirements, small cells have been deployed intensively by long term evolution (LTE) networks operators beside conventional base station structure to provide customers with better service and capacity coverage. Accomplishment of seamless handover between Macrocell layer (first tier) and Femtocell layer (second tier) is one of the key challenges to attain the QoS requirements. Handover related information gathering becomes very hard in high dense femtocell networks, effective handover decision techniques are important to minimize unnecessary handovers occurred and avoid Ping-Pong effect. In this work, we proposed and implemented an efficient handover decision procedure based on users’ profiles using Q-learning technique in an LTE-A macrocell-femtocell networks. New multi-criterion handover decision parameters are proposed in typical/dense femtocells in microcells environment to estimate the target cell for handover. The proposed handover algorithms are validated using the LTE-Sim simulator under an urban environment. The simulation results showed noteworthy reduction in the average number of handovers

Cell Selection Mechanism Based on Q-learning Environment in Femtocell LTE-A Networks

Universal mobile networks require enhanced capability and appropriate quality of service (QoS) and experience (QoE). To achieve this, Long Term Evolution (LTE) system operators have intensively deployed femtocells (HeNBs) along with macrocells (eNBs) to offer user equipment (UE) with optimal capacity coverage and best quality of service. To achieve the requirement of QoS in the handover stage among macrocells and femtocells we need a seamless cell selection mechanism. Cell selection requirements are considered a difficult task in femtocell-based networks and effective cell selection procedures are essential to reduce the ping-pong phenomenon and to minimize needless handovers. In this study, we propose a seamless cell selection scheme for macrocell-femtocell LTE systems, based on the Q-learning environment. A novel cell selection mechanism is proposed for high-density femtocell network topologies to evaluate the target base station in the handover stage. We used the LTE-Sim simulator to implement and evaluate the cell selection procedures. The simulation results were encouraging: a decrease in the control signaling rate and packet loss ratio were observed and at the same time the system throughput was increased

Self-configuration Concept to Solve Physical Cell ID Conflict for SON LTE-based Femtocell Environment

and Self-healing functions are the most important concepts for self-managing heterogeneous network. However, the concept of self-configuration can be used to solve various challenges in the femtocell deployment phase and also in the PCIs confusion and collision problems. However, the proposed solutions for interference mitigation are not satisfying and need further improvement. Two main reasons identified for this unsatisfactory, firstly the small number of femtocells used in the simulation scenario which can lead to high failure probability if applied under real enterprise environment, secondly; the provided solutions discussed only part of the problem,i.e. either in co-tier interference or cross-tier interference but not both. Thus the need arises for stable solution which can resolve the interference problem for both inter and intra scenarios. In addition among the tree types of approaches used to solve collision and confusion problems the Nokia Siemens approach was the best. Index Terms — Self-configuration, cross-tire and co-tier interference, SON, LTE-femtocell, interference. I

New graph colouring algorithm for resource allocation in large-scale wireless networks

The vertex-colouring problem is a well-known classical problem in graph theory in which a colour is assigned to each vertex of the graph such that no two adjacent vertices have the same colour. The minimum vertex-colouring problem is known as NP-hard problem in an arbitrary graph. In this paper a graph colouring algorithm based on modified incidence matrix is proposed for resolving Physical Cell ID (PCI) allocation for largescale femtocell deployment in LTE Telecommunication Networks. The proposed algorithm is not specified for neighbours only, but additionally can deal with neighbours of neighbours’ objects due to telecommunication requirements. Our results show that by applying proper searching and assigning methods it is possible to achieve satisfactory results for resource allocation in large and complex networks such as resolving PCI allocation and conflict for large femtocells deployment in LTE Networks

Femtocell geo-location challenge DSL approach as solution

Femtocell or Home eNode cell in LTE is a home base station that anticipated to be deployed in very large numbers with fully automated manner. Femtocell provides enhanced coverage for in‐building cellular services. The enhanced data rates enable new multimedia services which in turn generate new revenue. However, with all the convenience such device can provide, locating the user’s geographic location represents a great deal of challenge for law enforcement and operators alike. In this work we propose a simple and direct approach that does not require any changes in the network or in the femtocell standard design by exploiting the connection between the femtocell and the network operator through the DSL backhaul. Result shows the proposed approach has achieved successfully the goal of locating the geographic location of the femtocell user precisely