In the book, the authors provide a thorough overview of the high-altitude platform (HAP) enabling technologies. In addition, the book explores HAP-based communication systems, including issues related to aeronautics, applications and business modelling, as well as future trends. Furthermore, the authors discuss broadband wireless communications from HAPs, the operating environment, and advanced communication techniques for efficient radio link resource management. Similarly, the authors complement radio frequency (RF) dominated issues with free space optical communication.
COBISS.SI-ID: 23992615
In the article we propose an end-to-end service composition for information transport based on principles from Service Oriented Architecture (SOA), As we show, some SOA concepts are similar to concepts in Open Systems Interconnection (OSI) reference model, with the key advantages of dynamism and flexibility. We discuss Service Oriented Networks (SON) based on transport service composition across access and core segments. We show how semantic technologies can be used for an access network selection.
COBISS.SI-ID: 22803495
A new four-slope channel model for path loss prediction in road and railway tunnels at 400 MHz frequency band is proposed in the paper. A path loss model was built on the basis of field measurements. It consists of four different segments. Model applicability and accuracy were checked by calculating the mean error and standard deviation. Reasonable agreement between measurements and channel model was achieved. The four-slope path loss channel model is suitable for rapid and simple coverage prediction of direct mode operation in TETRA systems.
COBISS.SI-ID: 23606823
Free Space Optics (FSO) or optical wireless systems provide high data rate solution for bandwidth hungry communication applications. FSO links are highly weather-dependent. Employing a hybrid network consisting of an FSO link and a back up link in the GHz frequency range renders high availability of the communication link and provides comparable data rates. Effects of fog, rain and snow on FSO/GHz hybrid network are studied. It is suggested in the paper, that free space optical links can be supplemented with 40 GHz RF links to achieve near carrier class availability.
COBISS.SI-ID: 23243047
A novel SIP based procedure for congestion aware handover in heterogeneous networks is presented in the paper. With newly defined SIP messages the handover decision is based not only on signal strength, but also on target network status. Using the SIP protocol, this approach is completely independent of access technology and the underlying protocol used, and thus can be easily deployed in operator’s environments. The proposed procedure was evaluated with a purpose-built simulation model. The results show that the QoE of VoIP users is increased using new proposed procedure.
COBISS.SI-ID: 23990055