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The technology of software-defined devices has great prospect in updating the programs of the sensing devices to enable the devices to adapt to the new environments and applications. However, to effectively spread the code to each node in the software-defined-based wireless sensor networks (WSNs) is still a challenging task. In this paper, a proportion to duty cycle length-based broadcast (PDLB) scheme is proposed to disseminate code in duty cycle-based WSNs in a fast and energy-efficient style. In PDLB scheme, the sink first initiates a code broadcast. Then, the nodes that have received code start counting and calculate the priority of broadcasting based on an improved counter-based priority broadcasting approach proposed in this paper. Next, the nodes with the highest priority select k slots to broadcast according to the length of duty cycle so that the code can be spread from the sink to the network periphery. Finally, the nodes that have not obtained the code wait for a period of timeout to broadcast to actively send code request; after receiving code request, the node that obtained the code initiates a code broadcast to cause the code requester to obtain the code. The PDLB scheme has been validated by comprehensive experiments that show the following regularities. The smaller the count threshold value Ch, the larger the number of slots selected for broadcasting that can guarantee a certain coverage ratio, while the code dissemination speed slows down at the same time. The longer the duty cycle is, the more the broadcast time is required, and the larger the transmission delay is. For each slot added in a working cycle, the number of broadcasts is increased by 1.54%-33.33% and the transmission delay is augmented by 2.27%-70.04%. The higher the node density is, the shorter the code spread speed is. As the network density increases, the transmission delay is reduced by 0.83%-65.87%. When the number of broadcasting slots is half of the total number of slots in a work cycle, the energy consumption reaches the lowest value.

With the development of software-defined network (SDN) technology, sensor nodes can update soft codes to enable themselves to have new functions so as to make wireless sensor network (WSN) full of new vitality. However, how to spread the new code to every node in the network quickly and energy-efficient is a challengeable issue. In this paper, a Two-hop Neighborhood Information joint Double Broadcast Radius (TNI-DBR) scheme is proposed to disseminate the codes in duty cycle-based WSNs in a fast and energy-efficient style. The main innovations of this paper are as follows. The TNI-DBR scheme makes full use of the unbalanced energy consumption of the sensor network in the process of data collection and doubles the broadcast radius in the area with redundant energy so that more nodes can receive the new code in one broadcast and the broadcast range is further, which can reduce the delay of code dissemination effectively. Different from the conventional code dissemination schemes that select broadcasting nodes according to the information of the one-hop neighbors, in the TNI-DBR scheme, an $O(n)$ two-hop neighbor information exchange algorithm is proposed to obtain the duty cycle information of the two-hop neighbors. The TNI-DBR scheme selects the best broadcasting nodes based on information in the range of two-hop neighbors to enlarge the number of active nodes and reduce the time required for code dissemination. Sufficient theoretical analysis and experimental results show that the TNI-DBR scheme can significantly optimize the performance of code dissemination. Compared to previous schemes, the delay of code dissemination can be reduced by 43.09%~78.69%, the number of broadcasts can be reduced by 44.51%~86.18%, and the energy utilization ratio is improved by about 24.5%.

The Internet of Vehicles (IoV) has attracted increasing attentions for its potential of enhancing driving safety and traffic efficiency. The Multi-hop broadcast is one of the important techniques for time-sensitive data dissemination especially in emergent cases. As a result, how to wisely select the next-hop during Multi-hop routing plays an important role for performance improvement in IoV as well as dependent applications. Nevertheless, in view of the high mobility, frequent changing topology and complicated channel environment, a hazardous and thoughtless selection of the next-hop is easy to make, thus leading undesirable results. To deal with this issue, in this paper, a probabilistic broadcasting protocol for emergent message dissemination (BP-EMD) in Urban IoV is proposed. As the selection guidance for relaying node, the weighted probability is envisioned for each potential relay candidate, which is the combination of distance, link availability and packet reception ratio. After that, the node with the greatest weighted probability has been given the highest priority to relay the packet. In case that the selected relay node fails the forwarding, the other nodes available for relay will assist to disseminate the packet. In this way, the transmission reliability of the emergent messages is significantly guaranteed. Numerical results indicate that our BP-EMD can achieve higher broadcasting efficiency and less redundancy with less delivery latency, average transmission numbers and average End-to-End delay, as well as high packets delivery ratio and dissemination efficiency, compared with some classical multi-hop broadcasting protocols.

In this paper, we derive an accurate power model for video streaming which we condense to the essential components contributing the most to the overall power consumption. As a use case, we choose mobile devices on the receiver side performing video streaming in broadcasting or end-to-end scenarios. In modeling, we consider the complete video streaming toolchain, which mainly consists of data acquisition, video processing, display, and audio handling. We compose an overall power model with the help of models from the literature and propose a dedicated feature selection approach to reveal the most important factors related to power consumption. The resulting models achieve mean estimation errors below 7.61%. Results from feature selection indicate that the display brightness, the bitrate, and the frame rate have the highest impact on the power consumption.

This paper considers the transmission of scalable video via broadcast and multicast to increase spectral and energy efficiency in cellular networks. To address this problem, we study the use of generalized spatial modulation (GSM) combined with non-orthogonal hierarchical M-QAM modulations due to the capability to exploit the potential gains of large scale antenna systems and achieve high spectral and energy efficiencies. We introduce the basic idea of broadcasting/multicasting scalable video associated to GSM, and discuss the key limitations. Non-uniform hierarchical QAM constellations are used for broadcasting/multicasting scalable video while user specific messages are carried implicitly on the indexes of the active transmit antennas combinations. To deal with multiple video and dedicated user streams multiplexed on the same transmission, an iterative receiver with reduced complexity is described. 5G New Radio (NR) based link and system level results are presented. Two different ways of quadruplicating the number of broadcasting programs are evaluated and compared. Performance results show that the proposed GSM scheme is capable of achieving flexibility and energy efficiency gain over conventional multiple input multiple output (MIMO) schemes. info:eu-repo/semantics/publishedVersion

For large-scale photovoltaic module monitoring, wireless sensor network technology has been widely used, in which time synchronization is a significant factor. However, there are still outstanding issues in existing time synchronization algorithms for large-scale networking. To this end, this paper proposes a new Adaptive Energy-efficient Reference Broadcasting Synchronization method (AERBS) for wireless sensor networks, aiming to reduce the energy consumption whilst improving the synchronization precision. Moreover, the proposed method can reduce the number of synchronization information exchanges and self-adaptively determine the re-synchronization cycle. Simulation experiments demonstrate that our proposed AERBS outperforms the existing ERBS algorithm, in terms of reducing the synchronization number and the achieved reduction in energy consumption. The algorithm herein can be fully applied in the monitoring of large-scale photovoltaic module. At the same time, as a typical application of IoT (Internet of Things), it also provides a reference for distributed edge computing.

[EN] The current wide range of heterogeneous consumption devices and delivery technologies, offers the opportunity to provide related contents in order to enhance and enrich the TV consumption experience. This paper describes a solution to handle the delivery and synchronous consumption of traditional broadcast TV content and related broadband omnidirectional video content. The solution is intended to support both hybrid (broadcast/broadband) delivery technologies and has been designed to be compatible with the Hybrid Broadcast Broadband TV (HbbTV) standard. In particular, some specifications of HbbTV, such as the use of global timestamps or discovery mechanisms, have been adopted. However, additional functionalities have been designed to achieve accurate synchronization and to support the playout of omnidirectional video content in current consumption devices. In order to prove that commercial hybrid environments could be immediately enhanced with this type of content, the proposed solution has been included in a testbed, and objectively and subjectively evaluated. Regarding the omnidirectional video content, the two most common types of projections are supported: equirectangular and cube map. The results of the objective assessment show that the playout of broadband delivered omnidirectional video content in companion devices can be accurately synchronized with the playout on TV of traditional broadcast 2D content. The results of the subjective assessment show the high interest of users in this type of new enriched and immersive experience that contributes to enhance their Quality of Experience (QoE) and engagement., This work was supported by the Generalitat Valenciana, Investigacion Competitiva Proyectos, through the Research and Development Program Grants for Research Groups to be Consolidated, under Grant AICO/2017/059 and Grant AICO/2017

To enhance public safety, it is necessary to legitimately eavesdrop communication between suspicious users, such as terrorists and criminals. In this paper, we investigate legitimate eavesdropping in a wireless-powered suspicious communication network (WPSCN) with a wireless-powered suspicious transmitter and a suspicious receiver, who is legitimately eavesdropped by a legitimate monitor with the help from a wireless-powered friendly jammer. The “harvest-then-transmit” protocol is adopted by the suspicious communication to coordinate wireless energy transfer and information transfer. Both the suspicious receiver and the legitimate monitor can act as power sources for the suspicious transmitter and the jammer. The legitimate monitor can control the suspicious communication rate by broadcasting power signals, while the jammer can harvest energy and then interfere with the suspicious communication in collaboration with the legitimate monitor. Four different metrics are adopted to evaluate the eavesdropping performance based on different application requirements, and they are the successful eavesdropping probability, the average eavesdropping rate, the relative eavesdropping rate, and the eavesdropping energy efficiency. For each performance metric, we derive the optimal transmit power of the monitor for energy transfer and the optimal jamming transmit power of the jammer to maximize the performance metric under the peak transmit power constraint at the monitor and the energy causality constraint at the jammer. Some important insights are derived from these optimal power control policies. The simulations are conducted to verify the proposed optimal power control for legitimate eavesdropping in the WPSCN. It is shown that the proposed optimal power control policies greatly outperform other benchmark schemes.

Visible-light communication (VLC) is a new technique for high-speed, low-cost wireless data transmission services. One of the areas in which VLC is considered superior to traditional radio-based communication is security. The common slogan summarizing the VLC security features is WYSIWYS- “What You See Is What You Send.”However, the broadcast nature of downlink VLC makes it possible for eavesdroppers to easily intercept the light communication in various settings, e.g., offices, conference rooms, plenum spaces, and so on. Similarly to radio-based data broadcasting systems, such as Wi-Fi, VLC opens the possibilities of hiding information in the public channel. In this paper, we describe (for the first time, to the best of our knowledge) the implementation of steganographic data transmission in a VLC system called LuxSteg. This VLC system utilizes pulse position modulation and direct sequence-code division multiple access modulation. In our implementation, multiple steganographic data streams are mixed with the spreading codes and combined with the overt data stream. We achieve a steganographic transmission rate of approximately 1 Mb/s hidden in a 110-Mb/s data stream. We analyze the influence of the spreading factor, spreading code type, number of hidden data streams, and the amplitude on the achievable transmission rate, undetectability, and robustness.

In vehicular ad hoc networks (VANETs), the vehicles will periodically exchange information via broadcasting security-related message, such as the states of vehicles and roads, in which the performance may become worse when the vehicle density increases. To improve the poor performance of network when vehicular density is high, an adaptive back-off scheme based on improved Markov model is proposed in this paper. First, an improved Markov model with a contention window ( $CW$ ) inheritance mechanism is applied to reduce the network load. The vehicle with the improved model will take beacon expiration into account and actively discard expired beacons to relieve the pressure on the channel. Then, an initial $CW$ selection mechanism is designed to improve the efficiency of accessing the channel through providing the optimal initial $CW$ for the vehicles with different densities. Finally, we define a network busy factor to describe the condition of broadcast channel and propose an adaptive back-off algorithm which can dynamically adjust the $CW$ according to the network busy factor. Simulation results show that the new scheme can significantly improve the performance of broadcast.

Vehicular ad-hoc networks (VANETs) have been developed to provide safety-related and commercial service applications on the road. The IEEE 1609.4 is a standard (legacy) designed to support multi-channels in VANETs, namely control channel (CCH) and service channels (SCHs) with fixed alternating CCH and SCH intervals. The CCH is dedicated to broadcast safety and control applications while SCHs are used to transfer service data applications. However, due to the nature of contention-based channel access scheme and the transmission of multiple applications over the CCH during a fixed interval, safety applications performance is degraded during CCH congestion in high network density scenarios. In this paper, we propose an adaptive multi-channel assignment and coordination (AMAC) scheme for the IEEE 802.11p/1609.4 in VANETs which exploits channel access scheduling and channel switching in a novel way. AMAC scheme includes an adaptive execution of the peer-to-peer negotiation phase between service providers and users for SCH resource reservations, and collision-aware packet transmission mechanisms. These two mechanisms alleviate collisions and increase packet delivery ratio (PDR) of safety applications on the CCH. Thereby, the AMAC scheme ensures an efficient and reliable quality of service (QoS) for different traffic flows and improves the time diversity among vehicles based on the traffic conditions. For performance analysis, analytical models are developed based on 1-D and 2-D Markov chain models taking into account an error-prone channels. The probabilities of successful transmission and collisions have been derived to compute PDR, and delay for safety packets in legacy standard and AMAC scheme. Analytical and simulation results indicate that the AMAC scheme reduces the collisions and increases the PDR for safety applications over the CCH compared with the legacy standard. In addition, AMAC scheme outperforms the legacy standard in terms of system throughput of service applications.

Moving pictures experts group (MPEG) media transport (MMT) and MPEG-dynamic adaptive streaming over hypertext transfer protocol (MPEG-DASH) are emerging as the content-delivery technologies for the next-generation broadcasting systems, as they seamlessly utilize various underlying delivery networks to provide hybrid multimedia services in any location. In this paper, we present an empirical analysis of the channel-zapping time, which is an important metric in the measurement of the quality of experience (QoE) of broadcast services, regarding the MMT and MPEG-DASH technologies. During this process, we also clarify the important factors that determine the channel-zapping time of the individual technologies. In addition, we propose a simple yet effective method that enables fast channel zapping for the MMT technology.

In multi-hop relay networks, the improving end-to-end sum rate is a challenging issue. Although a new cooperative beamforming called virtual multiple-input multiple-output (MIMO) has been introduced as a possible solution, conventional virtual MIMO systems have severe signaling overhead among master and source nodes when the number of hops increases. To resolve this problem, a broadcast virtual MIMO system and a virtual MIMO broadcasting transceiver (VMBT) have been proposed to reduce the computational complexity and improve the end-to-end sum rate. However, the application of such methods is limited to environments wherein interference from other links and networks is not considered. Thus, it is difficult to apply them to practical multi-hop relay networks. In this paper, we propose a generalized version of the VMBT in which intra- and inter-network interferences are simultaneously caused by multiple transmission of clusters in the same network and each network’s usage of the same frequency band, respectively. To achieve this goal, we propose an effective interference nulling VMBT scheme. Simulation results show that the proposed scheme has efficient performance in terms of average end-to-end sum rate compared with conventional schemes.

In this paper, a new evaluation criterion is developed to investigate the performance of non-orthogonal multiple access (NOMA) from an information theoretic point of view. In particular, the relations among the capacity region of the broadcast channel and two rate regions achieved by NOMA and time-division multiple access (TDMA) are first illustrated. Based on these relations, a new evaluation criterion is proposed for NOMA in wireless fading scenarios, where the key idea is to compare NOMA with TDMA statistically in terms of not only the sum rate but also the individual rates. In a wireless downlink scenario with user pairing, the developed analytical results show that NOMA can outperform TDMA not only in terms of the sum rate but also in terms of each user’s individual rate, particularly when the difference between the users’ channels is large. The optimal power allocation for a special case of NOMA user pairing is also established.