The usability of wireless sensor networks in modern applications requires the fulfillment of dynamic Quality of Service (QoS) requirements that can only be met in a reactive manner by the introduction of composite routing metrics, capturing several distinct network characteristics. However, combining routing metrics is neither a trivial nor an arbitrary task, given the routing protocol requirements and routing metrics properties. In this paper, the theoretical framework of routing algebra formalism is adopted and extended to incorporate single or composite routing metrics, because the satisfaction of routing algebra properties ensures convergence, optimality, and loop‐freeness. Moreover, packet forwarding indication is defined as a new trust metric for systems (a) with or (b) without network retransmissions to avoid forwarding attacks, while a novel composite routing metric is presented, combining link reliability and trust‐awareness in an additive manner, fulfilling the theoretical requirements. Finally, this composite metric is applied to the Routing Protocol for Low Power and Lossy Networks via simulations, which verify its efficiency in several scenarios, including the comparison between lexical and additive metric composition approaches. Copyright © 2012 John Wiley & Sons, Ltd.

The spectral efficiency of the DVB-T protocol in comparison to the analog television systems will inevitably lead to the reduction of the UHF spectrum that is necessary for the current television broadcasts. Even if the number of available TV programs increases, or new services such as High Definition TV (HDTV) are introduced along with DVB-T, there will still be more available spectrum at any given area than today. The spectrum that will be released by most European countries when the full digital switchover is completed in 2012 has been designated as "digital dividend" and is a matter of controversy between broadcasters and mobile communications operators that wish to occupy part of it. This paper examines the coexistence of DVB-T and IMT-2000 mobile telecommunications in the UHF bands IV and V that are used today for television broadcasting on a primary basis. The situation in which both services operate in adjacent (or even in the same) channels is examined on both technical and regulatory grounds, so as to take into account the international standards and rules for television broadcasting and personal mobile communications, as expressed mainly by the International Telecommunications Union (ITU).

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