Antonios G. Alexiou

A Power Control Scheme for Efficient Radio Bearer Selection in MBMS

This paper proposes a power control scheme for the efficient radio bearer selection in the Multimedia Broadcast/Multicast Service (MBMS) framework of Universal Mobile Telecommunications System (UMTS). The choice of the most efficient transport channel in terms ofpower consumption is a key point for the MBMS since a wrong transport channel selection for the transmission of the MBMS data could result to a significant decrease in the total capacity of the system. Diferent UMTS transport channels are examined and an algorithm that defines the switching point between dedicated and common radio bearers is proposed The proposed MBMSpower control scheme selects the transport channel that reduces the Node Bs transmission power in every cell of the network with multicast users.

Using VR technology to support e-learning: the 3D virtual radiopharmacy laboratory

We present a virtual laboratory, which is designed and implemented in the framework of the VirRAD European project. This laboratory represents a 3D simulation of a radio-pharmacy laboratory, where learners, represented by 3D avatars, can experiment on radio-pharmacy equipment by carrying out specific learning scenarios. We describe the functionality provided by this laboratory, the motivation factors which led to its formation, the technological decisions that were made for the optimization of the system as well as the envisioned steps to be carried out.

An efficient multicast packet delivery scheme for UMTS

In this paper we present an efficient scheme for the multicast transmission of the data in the Universal Mobile Telecommunications System (UMTS). We take advantage of the tree topology of the examined network and we introduce the use of Routing Lists (RLs) in the nodes of the UMTS. The adoption of these lists leads to the decrement of the transmitted packets and the efficient use of network resources during the multicast transmission of the data. We describe in detail the necessary steps for the successful multicast transfer of data. Furthermore, we analyze the handling of special cases such as user mobility scenarios. Especially, the various handover types are examined along with the Serving Radio Network Subsystem (SRNS) relocation procedure.

Power saving techniques in mbms multicast mode

Multimedia Broadcast Multicast Services (MBMS) was introduced in Third Generation Partnership Project (3GPP) Release 6 in order to more efficiently use network and radio resources for the transmission of multimedia services both in the core network and, most importantly, in the air interface of UTRAN (UMTS Terrestrial Radio Access Network). From the radio perspective, MBMS includes point-to-point (PtP) and point-to-multipoint (PtM) modes. The latter aims to overcome network congestion when a large number of users request the same content. One of the most important aspects in MBMS is power control. The fact that Node Bs transmission power is a limited resource and must be shared among all MBMS users in a cell indicates the need for power control during an MBMS service. Techniques, such us rate splitting and mixed usage of transport channels can be used to reduce the power requirement of delivering multicast traffic for MBMS users. To this direction, this paper presents simulation results that will reinforce the need for the usage of such techniques and will reveal the amount of power that is saved.

Deployment of broadband infrastructure in the region of Western Greece

This paper presents the work that is taking place in the Region of Western Greece in order to develop state-of-the-art broadband infrastructure. The current status of broadband infrastructure in the region is being analyzed and the main principles on which the deployment of the networks will be based on is being described, by presenting the metropolitan area networks and the wireless access networks that will be developed. Two case studies of such municipal networks are also presented in this paper

An improved MBMS power counting mechanism towards long term evolution

One of the key objectives of beyond 3rd generation mobile networks is the realization of enhanced end-user experience through the provision of rich multimedia services. Multimedia Broadcast/Multicast Services (MBMS) framework epitomizes the increasing popularity of such applications and is envisaged to play an instrumental role for the Long Term Evolution (LTE) proliferation in mobile market. For exploiting resource efficiency, MBMS specifications consider the Counting Mechanism which decides whether it is more efficient to deliver MBMS multicast traffic over Point-to-Point (PTP) or Point-to-Multipoint (PTM) bearers. However, the necessity to further improve MBMS resource efficiency and integrate new technologies in the frame of LTE stresses the need for an advanced Counting Mechanism. In this work we propose a novel Power Counting Mechanism for efficient selection of MBMS bearers. The proposed mechanism optimally utilizes power resources and exploits broadband characteristics and performance enhancements emerged from Multiple Input Multiple Output (MIMO) antennas used in LTE networks.

MBMS Power Planning in Macro and Micro Cell Environments

Multimedia Broadcast Multicast Services (MBMS), introduced in Third Generation Partnership Project (3GPP) Release 6, is a point-to-multipoint downlink bearer service that addresses the need for the efficient usage of the expensive radio resources. Power control is one of the most important aspects in MBMS due to the fact that Node Bs transmission power is a limited resource and must be shared among all MBMS users in a cell. Consequently, the analysis of transmitted power plays a fundamental role in the planning and optimization process of Universal Mobile Telecommunications System (UMTS) radio access networks. This paper investigates several factors affecting Node Bs transmission power levels such as, cell deployment, propagation models, Quality of Service (QoS) requirements, users distributions and mobility issues. Finally, different transport channels for the transmission of the multicast data over the UTRAN interfaces are considered.

An improved mechanism for multiple MBMS sessions assignment in B3G cellular networks

In Universal Mobile Telecommunication System (UMTS), the downlink capacity is limited by the base station transmission power. Therefore, power control plays an important role to minimize the transmitted power shared among unicast and multicast users within a cell. In Multimedia Broadcast/Multicast Service (MBMS), power control targets to the efficient utilization of radio and network resources. However, the expected high demand for such services stresses the need for an efficient scheme, capable of dynamically allocating radio resources to parallel MBMS sessions. This paper proposes a power control mechanism for efficient MBMS session assignment in next generation UMTS networks. The mechanism shares efficiently the available power resources of UMTS base stations to MBMS sessions running in the network. Furthermore, the mechanism is evaluated through several realistic scenarios and the results indicate the ability of the mechanism to utilize efficiently the radio resources and to ensure the service continuity when parallel MBMS services run in the network. Our approach is compared with current 3rd Generation Partnership Project (3GPP) approaches, such as these presented in TS 25.346 and in TR 25.922, in order to highlight the enhancements that it provides.

Optimal MBMS Power Allocation Exploiting MIMO in LTE Networks

In the frame of the Long Term Evolution (LTE) of mobile networks, the provision of rich multimedia services, such as Mobile TV, is considered of key importance for the LTE proliferation in mobile market. To this end, Multimedia Broadcast/Multicast Service (MBMS) is envisaged to play an instrumental role during LTE standardization process. MBMS was introduced in the Release 6 of Universal Mobile Telecommunication System (UMTS) in order to deliver multimedia data from a single source entity to multiple destinations. However, downlink capacity in such networks is limited by base station transmission power. As an aftermath, in MBMS efficient power allocation techniques should be implemented so as to ensure the mass provision of multimedia applications to mobile users. In this paper we propose a power control scheme for efficient selection of MBMS bearers. The proposed mechanism on the one hand manages to economically utilize power resources during MBMS transmissions, while on the other hand exploits the performance enhancements emerged from Multiple Input Multiple Output (MIMO) antennas used in LTE networks. Simulation results indicate that the proposed scheme results to significant power and capacity improvements.

Evaluation of the Multicast Mode of MBMS

Multicasting is an efficient way for delivering rich multimedia applications to large user groups as it allows the transmission of packets to multiple destinations using fewer network resources. Content and service providers are increasingly interested in supporting multicast communications over wireless networks and in particular over universal mobile telecommunications system (UMTS). To this direction, the third Generation Partnership Project (3 GPP) is currently standardizing the multimedia broadcast/multicast service (MBMS) framework of UMTS. In this paper, we present an overview of the MBMS multicast mode of UMTS. We analytically present the multicast mode of the MBMS and analyze its performance in terms of packet delivery cost under various network topologies, cell environments and multicast users distributions. Furthermore, for the evaluation of the scheme, we consider different transport channels for the transmission of the data over the UTRAN interfaces and propose a cost based scheme for the efficient radio bearer selection that minimizes the packet delivery cost.