Ardian Ulvan

The study of handover procedure in LTE-based femtocell network

Wireless systems have the capability to address broad geographic area without the costly infrastructure deployment. However, the main drawback resides in the bandwidth limitation and the coverage for single access point. The deployment of Femtocell as the promising wireless access technology becomes one of the possible solution. In this paper the handover procedure in femtocell network is studied. The 3GPP LTE based handover is analysed in three scenarios: hand-in, hand-out and inter-FAP. In addition, the reactive and proactive handover strategy is also proposed as the handover decision policy to diminish the very frequent and unnecessary handovers.

Handover procedure and decision strategy in LTE-based femtocell network

Wireless systems have the capability to serve users over broad geographic area without using a costly network infrastructure. However, the main drawback of these systems represents the bandwidth restrictions and coverage. Deployment of femtocell as the emerging promising wireless access technology becomes one of possible solution how to overcome some of the drawbacks. In this paper, we investigate the handover procedure in femtocell network considering, both types of handovers, horizontal and vertical. The 3GPP LTE based handover procedure is analysed for three scenarios: hand-in, hand-out and inter-FAP. In addition, the reactive handover decision policy, based on the prediction of user movement and the prediction of target-FAP, is proposed as a way to eliminate frequent and unnecessary handovers.

The Analysis of Scanning Time in IEEE802.16m's Handover Procedure

In this paper we analyze the efficiency of scanning process on handover procedure in IEEE802.16 m. Since the .16 m is still under development, the performance evaluation is based on current running standard of 802.16 e. We consider four scan types and evaluate the average scanning time required. In addition, four different handover strategies are utilized to analyze the handover interruption time. The evaluation is done at both parts of handover procedure i.e. network topology acquisition and handover process. The efficient scanning process is proposed to reduce the scanning time and obtained a minimal handover interruption time.

The study of IMS functionality in femtocell environment

In this paper, the deployment of IMS functionality in femtocell environment is investigated and overviewed. Femtocell is a small cellular base station designed for use in residential or small business environments. It allows service providers to extend service coverage inside of our home, especially where the existing access is limited or unavailable. In the mean time, the IMS, as emerging framework of fixed and mobile convergence, provides the functionalities that accommodate current and future services in wired and wireless networks (e.g. voice, video and data transfers). Configuring the IMS framework in new approach of network architecture such as femtocell and designing the femtocell network to support IMS services is quite demanding. Some possible network design will be discussed. In this paper we concern on the investigation of IMS SIP signalling when it works on femtocell environment. Another critical issue such as the delay properties of session establishment signalling is also interesting to be discussed. The IMS-based and Cellularbased approaches for the integration of femtocells system and IMS core network are discussed.

IEEE802.16 MAC Management Messages: The overhead and efficiency analysis in mesh topology

This paper presents the analysis of MAC Layer (L2) in wireless broadband system based on WiMAX IEEE802.16. The analysis is focused on overhead and efficiency of MAC Management Message and derived for mesh topology. The Mesh topology is evaluated concerning both existing types of scheduling - centralized and distributed - and their performance is compared. Some parameters, which deduced to have considerable influences i.e. the number of subscriber stations in the network, number of hops, various modulation and coding, and length of MAC PDUs, are assigned as the overhead parameters. The results show those parameters have significant impact on the efficiency of MAC layer.

Retransmission issue of SIP session over UDP transport protocol in IP Multimedia Subsystem - IMS

In this paper, the ability of SIP session over UDP transport protocol retransmission issue in IMS network is investigated and analysed. We described SIP session in IMS with end-to-end SIP signalling flow through the IMS entities such as P-CSCF, I-CSCF, S-CSCF and HSS, including the involvement of related SIP messages. The UDP retransmission issue, e.g., INVITE request and loss rates parameters, were conducted to determine the loss of sessions. It has been found that the gradual increase of session loss occurred after the first attempt of transmission. It is affected by the request rates and loss rates. Therefore, the deployment of RFC3261 TimerB and T1 with value of 32s and 0.5s respectively, will prevent the SIP system from the huge number of retransmission.

The Efficiency Performance on Handover's Scanning Process of IEEE802.16m

This paper investigates the efficiency of scanning process on handover procedure in IEEE802.16m. The performance evaluation is based on current running standard of 802.16e since .16m is still under development. The evaluation is done at both parts of handover procedure, i.e. network topology acquisition and handover process. An efficient scanning process is proposed to reduce the scanning time and obtained a minimal handover interruption time.

The analysis of IEEE802.16e MAC layer overhead and efficiency in PMP topology

This paper presents an analysis of the IEEE 802.16e MAC overhead. The efficiency on the MAC layer is derived for Point to Multipoint (PMP) topology. The influence of several parameters is examined. The parameters, such as the number of subscriber stations in the network, various modulation and coding, and length of MAC PDUs, are assigned as the overhead parameter. The results show these parameters have significant impact on the efficiency of MAC layer. Finally, some recommendations to reduce the overhead are put forward.

Multiple Cell Partitions for Increasing the CDMA-Based Cell Capacity

This paper investigates the impact of cell partitioning in cell capacity of CDMA-based system. We examine the implementation of four partitions per cell as well as the influence of various height of the base station transceiver antenna to the system. We contemplated the urban area as the target, therefore the COST-231 Walfisch – Ikegami is applied as the propagation model. Calculations on the capacity of cell, the link budget (and MAPL) and the radius of each partition, depending on the height of the base station transceiver antenna, are made. The results show that the capacity increases as the number of partitions increases; the height of the base station transceiver affects the radius of the partitions.

Transmission Performance of Flexible Relay-based Networks on The Purpose of Extending Network Coverage

Wireless mobile terminal may performs as relay for some other terminals which require relaying assistance. The deployment of flexible relaybased wireless networks is expected to increase the capacity of the network when placed within the base station. It also extends the coverage when placed at the border of base station coverage. In this paper, the performance evaluation of transmission between mobile nodes at the border coverage is carried out. The CDMA-based network with frequency hopped and direct sequence was applied. The Erlang capacity is used as the main parameter. The results show, the relay nodes can extend the coverage, however the transmission performance have been limited by blocking probability and signal to noise ratio (E b /N o ). The results also show FH-CDMA has better performance than DS-CDMA.