Dimitris Komnakos

Emergency m-Health Services through High-Speed 3G Systems: Simulation and Performance Evaluation

The present paper studies the prospective and the performance of a forthcoming high-speed third-generation (3G) networking technology called High Speed Packet Access (HSPA) for delivering emergency m-health applications. The joint transmission of voice, real-time video, medical data such as electrocardiogram, vital signals, heart sound and file transfer is performed for both uplink and downlink. Various scenarios are involved in terms of emergency situations in random locations, where no other system but 3G is available. The accomplishment of quality of service (QoS) is explored through a step-by-step improvement of HSPA systems parameters, incorporating admission and congestion control elements and the use of prioritization for m-health services. HSPA managed to meet the requirements for emergency m-health scenarios and adequately served the generated load.

Non-ionizing electromagnetic radiation monitoring in Greece

The design, development, and operation of a network for the monitoring of the non-ionizing electromagnetic radiation in Greece is presented in this paper. Two independent sub-networks, called “Hermes” and “pedion24” have been operating since November 2002 in many areas, and more than 4,000,000 electric field strength measurements have been conducted to date. The measurement results indicate that the non-ionizing electromagnetic radiation levels are several times below the European Commission Recommendation 1999/519/EC and the Hellenic Republic Law no. 3431 reference levels.

Performance Evaluation of an Enhanced Uplink 3.5G System for Mobile Healthcare Applications

The present paper studies the prospective and the performance of a forthcoming high-speed third generation (3.5G) networking technology, called enhanced uplink, for delivering mobile health (m-health) applications. The performance of 3.5G networks is a critical factor for successful development of m-health services perceived by end users. In this paper, we propose a methodology for performance assessment based on the joint uplink transmission of voice, real-time video, biological data (such as electrocardiogram, vital signals, and heart sounds), and healthcare records file transfer. Various scenarios were concerned in terms of real-time, nonreal-time, and emergency applications in random locations, where no other system but 3.5G is available. The accomplishment of quality of service (QoS) was explored through a step-by-step improvement of enhanced uplink systems parameters, attributing the network system for the best performance in the context of the desired m-health services.

Dynamic subchannel and slot allocation for OFDMA networks supporting mixed traffic: upper bound and a heuristic algorithm

Optimizing resource allocation over only the frequency dimension in a single-cell OFDMA network is strictly suboptimal when heterogeneous non-real-time data users coexist. In this work we examine how to jointly exploit multi-user diversity on frequency and time domains towards maximizing cell throughput performance and satisfying individual rate and fairness QoS constraints. We develop a performance upper bound as well as an efficient heuristic algorithm for subcarrier and slot allocation which outperforms existing algorithms under polynomial complexity.

QoS Study Performance of an Integrated Satellite Telemedicine Platform

This paper describes a wide-area tele-medicine platform, specially suited for homecare services, based on the DVB-RCS and Wi-Fi communication technologies. Implementation of DVB-RCS, utilizing dynamic assignment techniques mandated in the DVB-RCS specification, has been specifically designed and tuned for multimedia and high-speed data transfer. The monitored patients can be practically anywhere, even in geographically dispersed and isolated areas, where normally there is no terrestrial communications infrastructure capable of supporting similar services. The presented platform combines medical data acquisition and transfer, patient remote monitoring and teleconference services. Possible operational scenarios simulated and results regarding available data rates, quality of service (QoS) provision, and prioritization of tele-monitoring, videoconference and medical data transfer are provided and discussed in the paper.

Mobile networks planning for minimum power consumption

Energy consumption minimization of mobile networks is a growing concern for the research community in recent years. As networks are most of the time underutilized due to spatial and temporal traffic fluctuations, we propose an algorithm to optimally determine the operational mode of Base Stations (BS) under certain traffic load conditions to achieve overall energy efficient mobile network operation. The proposed algorithm and simulation environment are both implemented in Matlab. Simulation results show that, under all traffic loads and topology scenarios examined, our proposed scheme outperforms a previously proposed algorithm, while the results are very close to optimum.

Linear modeling and performance evaluation of resource allocation and user scheduling for LTE-like OFDMA networks

A linear model for evaluating the performance of adaptive resource allocation and user scheduling regarding a single-cell downlink SISO-OFDMA packet data network like LTE is developed in this paper. Based on this model several power, bit, frequency block and frame allocation approaches are examined and the corresponding performance upper bounds are numerically extracted. We put a special emphasis on equal power allocation and single modulation mode per user approaches, since they are proposed by the 3GPP standardization body. The individual and joint effect of each system degree of freedom to the overall performance is thoroughly discussed. The merit of the specific model is that it provides us with the performance upper bounds spending polynomial execution time.

Enhanced dedicated channel scheduling optimization in WCDMA

Enhanced Uplink operation of WCDMA-UMTS systems utilizes fast Node B scheduling and a short Transmission Time Interval (TTI) of 2ms. The scheduling decisions are based on scheduling information (SI) sent by each UE to the Node B. The main drawback of the current scheduling procedure is that the SI does not include any information regarding the delay sensitivity of each traffic flow, as well as the actual delay that the buffered data have experienced. In this paper, we propose the inclusion of such information in SI by introducing a modification of the respective 3GPP specifications. Furthermore, we propose a Dynamic Priority Scheduler (DPS), which can utilize this new information. The performance of the proposed scheme is evaluated by means of system level simulations.

Feasibility Study of a HSPA Backhauling over Satellite for Crisis Management

The present paper studies the performance of a high-speed third- generation (3.5G) networking technology, HSPA (High Speed Packet Access), for delivering crisis management and emergency e-health applications under urgent situations via satellite backhauling. The performance of a joint network comprised by wireless sensors, the 3.5G and satellite networks is a critical factor for successful development of emergency services perceived by end-users during a disaster situation. In this paper, we propose an emergency system architecture for performance assessment based on the joint transmission of voice, real-time video, vital data and healthcare records file transfer between the disaster-site and the safe-site. Three scenarios were concerned in terms of real-time, non-real- time and emergency applications in random locations, where no other system but 3.5G is available in case of crisis or disaster. The accomplishment of quality of service (QoS) was explored through a step-by-step improvement of the HSPA and satellite systems parameters, attributing the network system for best performance in the context of the desired emergency services.

Green Optimization Schemes for Mobile Network Design and Operation

Mobile telecommunication’s operation power cost occupies a large portion in network operators OPEX list. Recent research efforts on energy efficient design and optimization of the radio access network focus on applicable solutions that decrease the energy consumption of the vast number of radio base stations (BSs), mostly because of the economic and environmental consequences of their operation. In this work, we formulate the power consumption optimization problem in mobile networks and propose two energy efficient heuristic schemes to determine the optimal subset of available BSs that should be active in order to serve a certain load of UEs, without violating QoS requirements for each user served. We exploit the results of this formulation setup and further propose a BS activation scheme to produce proper BS activation profiles for continuous time operation in the same network deployment under various user traffic demands. The results indicate that our proposed BS optimization and activation schemes achieve significant energy savings compared to ordinary network operation