Jani Vare

Soft handover in terrestrial broadcast networks

The 3rd generation mobile cellular communication systems will provide high-capacity bandwidth, enabling rich media and even TV services to be accessible via mobile handheld devices. For the reception of such services, seamless mobility is a must rather than an option. Alternatively, Digital Television standards, particularly data broadcasting in Terrestrial Digital Video Broadcasting (DVB-T), can be used for the delivery and reception of similar services. However, the current DVB-T standard lacks adequate methods that enable seamless mobility. In cellular delivery systems, this can be achieved by so-called soft handovers. time slicing is a recent enhancement proposed for the new - still being developed - Digital Video Broadcasting for handheld (DVB-H) standard, which together with DVB-T enables a feasible solution for soft handover to be implemented. This paper considers how time slicing can be utilized in implementing soft handover in a DVB-H receiver. An algorithm for soft handover is proposed and evaluated.

A survey of handover algorithms in DVB-H

Digital video broadcasting for handhelds (DVB-H) is a standard for broadcasting IP Datacast (IPDC) services to mobile handheld terminals. Based on the DVB-T standard, DVB-H adds new features such as time slicing, MPE-FEC, in-depth interleavers, mandatory cell id identifier, optional 4K-modulation mode and the use of 5 MHz bandwidth in addition to the usually used 6, 7, or 8 MHz raster. IPDC over DVB-H is proposed for ETSI to complement the DVB-H standard by combining IPDC and DVB-H in an end-to-end system. Handover in such unidirectional broadcasting networks is a novel issue. In the last few years since the birth of DVB-H technology, great attention has been given to the performance analysis of DVB-H mobile terminals. Handover is one of the main research topics for DVB-H in mobile scenarios. Better reception quality and greater power efficiency are considered to be the main targets of handover research for DVB-H. New algorithms for different handover stages in DVB-H have been the subject of recent research and are currently being studied. Further novel algorithms need to be designed to improve the mobile reception quality. This article provides a comprehensive survey of the handover algorithms in DVB-H. A systematic evaluation and categorization approach is proposed based on the problems the algorithms solve and the handover stages being focused on. Criteria are proposed and analyzed to facilitate designing better handover algorithms for DVB-H that have been identified from the research conducted by the authors.

Approach for improving receiver performance in loss-free handovers in DVB-H networks

DVB-H (digital video broadcasting for handheld) is one of the key technologies that enables new services, such as mobile phone TV, to be used in handhelds. DVB-H enhances mobile features found in the DVB-T standard, enabling new techniques, e.g., loss-free handover. For services such as mobile TV, loss-free handovers must be supported. Different positioning technologies, such as GPS, also play an important role in enhancing todays mobile technologies. The paper proposes a new feature for DVB-H, a new method for signalling cell coverage area, thus improving performance for loss-free handovers. The proposed method is targeted at DVB-H handhelds that have GPS receivers. The benefits of the proposed method for handover and power consumption are evaluated. In addition, its effect on the consumption of bandwidth and receiver memory is estimated.

A prioritization method for handover algorithm in IPDC over DVB-H System

DVB-H (Digital Video Broadcasting for Handheld) is a standard that was developed to enable broadcast distribution of multimedia services such as MobileTV to the handhelds. The DVB-H standard was further enhanced by IPDC over DVB-H standard which defined complete end- to-end DVB-H system and hence maximized the interoperability between networks and terminals. Even though standards enable complete solutions for implementation, there are several different ways to realize the actual terminal implementation. One of the key features within DVB-H and IPDC over DVB-H standards is to ensure the reception of services when terminal switches the point of reception, i.e. performs handover. The latter has been a topic of research for a quite some time and several different approaches have been provided. This paper introduces another element for the handover and particularly for the implementation of handover algorithm. A prioritization method for handover algorithm in IPDC over DVB-H system is presented.

Laborator Measuremeots and Verification of PSI/SI Transmission iIn DVBH Systems

PSI/SI is the core part of service discovery within all DVB systems. The PSI/SI needs to be received by the receiver, before it is able to start to consume the services. In the fixed reception, the robustness of PSI/SI is not as important as it is in the handheld systems, such as in DVB-H. Some studies have been carried out to investigate the robustness of PSI/SI and especially the mechanisms to guarantee the robustness on the same level as it is within the data transmission. This paper completes the earlier studies on PSI/SI robustness, by providing the results of the laboratory measurements where the robustness of PSI/SI was investigated.