Modem Configuration Research Articles

ETSI-Standard Reconfigurable Mobile Device With an Opportunistic Multi-Antenna System Based on Radio and Non-Radio Contexts

In state-of-the-art mobile devices (MDs), non-radio contexts (i.e., non-real-time data) provided by various sensors have been excluded in determining the modem configuration because of the problems in applying them in real-time modem operations. This paper presents a reconfiguration procedure and hardware implementation of a European Telecommunications Standards Institute (ETSI)-standard reconfigurable MD with a multi-antenna system. Borrowing the ETSI-standard architecture, the proposed MD can exploit a high-level abstraction of configuration-related operations, which consequently provides its application processor operating in non-real-time domain a uniform way of managing the multi-antenna-related hardware platform operating in real time. The configuration of the proposed MD is determined in accordance with non-radio and radio context information for opportunistically utilizing multiple antenna resources. From an implemented multi-antenna MD system operating in an indoor layout and computer simulations of the multi-antenna MD operating in a modeled outdoor layout, we verify that the MD configuration can be optimized in accordance with radio and non-radio contexts not only for fixed indoor but also for mobile outdoor environments. This enables the multi-antenna MD to efficiently utilize its antenna resources, such that the throughput maximization and/or power consumption minimization can be achieved.

Simplified adaptively modulated optical OFDM modems using subcarrier modulation with added input/output reconfigurability

Three novel designs of adaptively modulated optical orthogonal frequency division multiplexing modems using subcarrier modulation (AMOOFDM-SCM) are proposed, for the first time, each of which requires a single inverse fast Fourier transform/fast Fourier transform (IFFT/FFT) operation. These designs not only significantly simplify the AMOOFDM-SCM modem configurations, but also offer extra unique network features such as input/output reconfigurability. Investigations show that these three modems are capable of supporting more than 60 Gb/s AMOOFDM-SCM signal transmission over 20, 40 and 60 km single mode fibre (SMF)-based intensity modulation and direct detection (IMDD) transmission links without optical amplification and chromatic dispersion compensation.

DVB‐S2 ACM modes for IP and MPEG unicast applications

AbstractThe DVB‐S2 standard (ETSI: EN 302 307. Digital Video Broadcasting (DVB): second generation framing structure, channel coding and modulation systems for Broadcasting, Interactive Services, News Gathering and other broadband satellite applications (DVB‐S2)) has been conceived for several satellite broadband applications: Television Broadcast Services, Interactive Services including Internet Access by consumers, Professional Applications such as Digital Satellite News Gathering (DSNG) and TV distribution, data trunking. This paper focuses on the profiles supporting interactive type of services, for which Adaptive Coding and Modulation (ACM) has been included in the new generation of the standard. Following the DVB‐S2 specifications, a number of modem configurations and tools are made available for implementing ACM in interactive systems. However, the different approaches have important impacts on the design of the system architecture and of the scheduling/resource management algorithms. The aim of the present contribution is providing a first discussion on the critical issues at system and MAC level, which need to be addressed when implementing a DVB‐S2 ACM system. A general introduction to ACM is also provided, as well as an illustration of the key elements included in the DVB‐S2 standard for supporting physical layer adaptivity. Copyright © 2004 John Wiley & Sons, Ltd.