The lack of available spectrum for wireless communications is a threat to the successful deployment of applications designed for intelligent transportation systems (ITSs). The ITS services should be available to a high number of road users and have a fast response time. The interworking between radio access networks is one way to increase spectrum availability. In particular, the joint operation of the dedicated short-range communication (DSRC) technology and TV white spaces (TVWS) has been proposed to increase the dissemination distance for safety messages in vehicular networking. However, previous works have often assumed that the only restriction on the opportunistic access of TVWS is the presence of a TV transmitter (i.e., the primary user). Other secondary users, such as the popular White-Fi networks to be deployed in TV bands, are omitted from the analysis of opportunistic channel access over TVWS. This is despite several proposals in the literature that use secondary networks for purposes other than vehicular networking over TVWS. In this paper, we analyze the opportunistic use of TVWS when other fixed users, such as White-Fi networks, are present. We estimate channel access opportunities and introduce a new metric, the channel availability for opportunistic vehicular access (CAFOVA), which relates the channel occupancy of the White-Fi network, the speed of the vehicle, and the channel verification distance. The results show that there are opportunities for vehicular access even when a White-Fi network occupies the TVWS. Vehicles may use these opportunities for transmission, instead of spending time looking for a new available TVWS and establishing a new link with another vehicle. Therefore, even when a White-Fi network occupies the same TVWS, it may be possible to exploit dynamic spectrum access to extend the available spectrum for vehicular communications.INDEX TERMS TV primary user, TV white spaces, vehicular dynamic spectrum access, White-Fi network.The associate editor coordinating the review of this manuscript and approving it for publication was Arun Prakash.active road safety, cooperative traffic efficiency, and information and entertainment (also known as Infotainment). As shown in Table 1, each category has different latency, coverage, and data rate requirements, but all categories are subject to performance challenges due to the different node speeds and network densities encountered in vehicular scenarios.Channel availability is a fundamental requirement for the successful operation of vehicular applications, but the lack of available spectrum for wireless technologies is a threat for current and future applications designed for ITS. For example, in the presence of traffic congestion, the sending of a critical warning message may fail when concurrent transmissions

When a natural or human disaster occurs, time is critical and often of vital importance. Data from the incident area containing the information to guide search and rescue (SAR) operations and improve intervention effectiveness should be collected as quickly as possible and with the highest accuracy possible. Nowadays, rescuers are assisted by different robots able to fly, climb or crawl, and with different sensors and wireless communication means. However, the heterogeneity of devices and data together with the strong low-delay requirements cause these technologies not yet to be used at their highest potential. Cloud and Edge technologies have shown the capability to offer support to the Internet of Things (IoT), complementing it with additional resources and functionalities. Nonetheless, building a continuum from the IoT to the edge and to the cloud is still an open challenge. SAR operations would benefit strongly from such a continuum. Distributed applications and advanced resource orchestration solutions over the continuum in combination with proper software stacks reaching out to the edge of the network may enhance the response time and effective intervention for SAR operation. The challenges for SAR operations, the technologies, and solutions for the cloud-to-edge-to-IoT continuum will be discussed in this paper.

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Radio Spectrum is the natural resource that allows the operation of radio services, such as Television, Mobile Telephony, and applications for Intelligent Transportation Services, Internet of Things, among others. The current allocation system is inefficient because assigned spectrum is not fully utilized by operators and cannot be accessed by any other user, despite its availability. Secondary spectrum usage is proposed as an alternative to optimize its use, allowing that a secondary user can access certain portion of spectrum allocated to primary service. In particular of TV service, this portion is known as TV White Space, TVWS. The most common models to identify available spectrum in TV service are based on frequency allocation and network planning information provided by TV operators, which are not enough to make an accurate estimation. A spectrum detection model built with traditional models and analysis of coverage maps obtained by simulations is presented, and applied in Cali Colombia to establish how many TVWS are available, taking into account the effect that terrain has on the propagation of the service. The amount of TVWS detected increases using our model compared to TVWS identified only with traditional models. © 2016 IEEE