Towards video streaming in IoT Environments: Vehicular communication perspective
Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and
... vehicular traffic environment can be captured and transmitted using vehicle-tovehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, the significance of video streaming in vehicular IoT environments is highlighted focusing on the integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues. that there will be more than 50 billion interconnected devices by the year 2020 . The interconnected devices of which more than 90% will be of distinctive IoT devices including small embedded computers, wearable devices, vehicles and application-specific wireless sensors. It is considered that the highest data traffic generated from the IoT devices would be multimedia data including images, audio and video. The multimedia traffic will be about 80% of the overall Internet data traffic by the year 2019  . Alvi, et al. , suggested a new paradigm named as "the Internet of Multimedia Things (IoMT)" and claimed that multimedia is an indispensable part of IoT. However, in the multimedia data, we focus on video data and for the IoT communication devices and emphasize on vehicles to vehicle and vehicles to IoT devices. Mobile network has introduced a new paradigm called Vehicular Ad-hoc Networks (VANETs) with the focus on inter-vehicle communication for safety and efficiency in travelling and transportation [5, 6] . In VANETs, vehicles act as higher mobility aided network nodes, and facilitates traffic oriented communication. It comprises of Roadside Units (RSUs), On-board Unit (OBU), and in-built sensors with vehicles. RSUs are installed beside roads in urban and highway environments. RSUs enable smooth vehicular communication in two modes including Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I). The OBUs are often fitted inside vehicles such as DSRC devices which supports short distance and high speed communication via V2V and V2I  . The vehicular communication paradigm is based on co-operative communication and networking for realizing Intelligent Transportation Systems (ITS) [8, 9] . It defines various applications including emergency brake cautioning, cooperative navigation control, security distance cautioning, driver support, collision cautioning and supportive driving    . Vehicles as network nodes do not have the battery power issue, because of its high capacity automatic rechargeable battery via engine. This facilitates intensive data communication and processing capability in vehicular cyber physical system network environments [13, 14] . Due to the recent advancements in intelligent communication gadgets for vehicles including smart antenna, Global Positioning System (GPS), and smart onboard buffer, video streaming forwarding and cooperative downloading over V2V and V2I have been realized  . In order to explore video communication among vehicles, the text message and beacon signal based communication among vehicle have to be discussed as existing literature. As in vehicular communication, the vehicles entails wireless OBUs, which facilitates communication among vehicles and RSUs with DSRC standard  . Each vehicle periodically broadcast its current information including location, speed, direction etc. By using the periodical information, the neighboring vehicles can take early decision in case of traffic incidence for example traffic jam, accident and emergency braking  . In addition, advertisement, downloading and uploading data via native information acquisition for example, road maps, groceries, restaurants, hotel, fuel stations  . However, all the aforementioned applications are text or beacon signal based, which do not provide realistic traffic information or on-road traffic situations for example, level of traffic jam, severity of accident and actual position of incidence. Meanwhile, in video streaming of on-road situation, the vehicle displays actual position of other vehicles, level of traffic jams and severity of an on-road accident in order to take appropriate responsive actions. The OBUs display device is used for streaming video using the DSRC network connections among vehicle and the RSUs. Hence, video streaming is considered as one among the treasured VANETs applications  . The video streaming for communication is applicable for user-to-vehicle and user-to-office video conferencing  . Infotainment in vehicles can be made more realistic by video streaming for notice and advertisement of on road shopping malls, clinics, and nearby gas stations  . Consequently, video streaming applications can meaningfully improve the vehicle user experience during navigation.