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This paper investigates secure broadcast communications in intelligent reflecting surface (IRS)-aided millimeter wave (mmWave) symbiotic radio (SR) networks, where the IRS and the base station (BS) are cooperating. Specifically, the IRS assists secure broadcasting for the BS by smartly reconfiguring the phase shifts of the signals from the BS, while delivering its own information to an Internet-of-Things device (IoD). We aim at maximizing the minimum secrecy rate of multiple users by jointly designing the hybrid precoder at the BS and the passive beamformer at the IRS, subject to the rate constraints of both the multiple users and the IoD. The design is formulated as a non-convex optimization problem, which is intractable. To handle it, we develop a computationally efficient iterative algorithm based on the successive convex approximation, the efficiency and superiority of which have been validated by simulation results. [ABSTRACT FROM AUTHOR]

In this paper, we consider the issue of data broadcasting in mobile social networks (MSNets). The objective is to broadcast data from a superuser to other users in the network. There are two main challenges under this paradigm, namely 1) how to represent and characterize user mobility in realistic MSNets; 2) given the knowledge of regular users' movements, how to design an efficient superuser route to broadcast data actively. We first explore several realistic data sets to reveal both geographic and social regularities of human mobility, and further propose the concepts of geocommunity and geocentrality into MSNet analysis. Then, we employ a semi-Markov process to model user mobility based on the geocommunity structure of the network. Correspondingly, the geocentrality indicating the “dynamic user density” of each geocommunity can be derived from the semi-Markov model. Finally, considering the geocentrality information, we provide different route algorithms to cater to the superuser that wants to either minimize total duration or maximize dissemination ratio. To the best of our knowledge, this work is the first to study data broadcasting in a realistic MSNet setting. Extensive trace-driven simulations show that our approach consistently outperforms other existing superuser route design algorithms in terms of dissemination ratio and energy efficiency. [ABSTRACT FROM PUBLISHER]

In cellular environments, video broadcasting is a challenging problem in which the number of users receiving the service and the average successfully decoded video data-rate have to be intelligently optimized. When video is broadcasted using the 3G packet data standard, 1xEV-DO, the code space may be divided among the multiple layers if scalable video coding is employed. In this paper, we propose a novel, multi-objective optimized video broadcasting scheme for 1xEV-DO and investigate the feasibility of using multiple layers for transmission. The multi-objective optimization aims to find the best compromise between maximizing the average decodable video data-rate and minimizing the basic quality video outage probability. Simulations conducted for the ITU Pedestrian A and Vehicular B channels show that high data-rates with low outages are possible when 1xEV-DO is used for video broadcasting, however, it may not be desirable to use scalable video coding for this purpose. [ABSTRACT FROM AUTHOR]

There are many asynchronous communication situations for which the prevalent continuous connectivity paradigm is not needed. Communication with a fair delay tolerance may instead be provided by intermittent store-and-forwarding between nodes. This paper proposes a design for an open, receiver-driven broadcasting system that relies on delay-tolerant forwarding of data chunks through mobility of wireless nodes. The system provides public broadcast channels, which may be openly used for both transmission and reception. We show by analysis and simulation under benchmark mobility models that a delay-tolerant broadcast channel has both a sufficiently high throughput and reach to be interesting as a competitive alternative to the regulated wireless broadcast channel. The analysis is based on a queuing model to study the interactions among the mobile nodes in a street. The simulations complement this analysis for mobile nodes moving on a square according to benchmark mobility models. Finally, we present the design of, and experiences with, a proof-of-concept prototype. [ABSTRACT FROM AUTHOR]

DVB-H is a new broadcasting standard, which offers reliable high data rate reception of IP packets for mobile handheld battery-powered devices. A link layer with multiprotocol encapsulation (MPE), including Reed-Solomon forward error correction (FEC) combined with a cyclic redundancy check (CRC), is defined in the standard to work on top of the DVB-T physical layer. For error correction in the receiver the DVB-H standard suggests to use erasure decoding based on the CRC information. Yet, the decoding method is not strictly determined in the standard. This paper investigates the performance of five different Reed-Solomon decoding schemes for the DVB-H link layer forward error correction called MPE-FEC. They differ on utilization strategy of existing erasure information. The performance of different decoding methods are evaluated analytically in an binary symmetric channel (BSC) and with simulations in the additive white Gaussian noise (AWGN) and a mobile fading channel. For the simulations in the fading channel a packet channel model based on actual measurements is designed. It is shown that more sophisticated decoding methods than the one suggested in the standard are required for efficient retrieval of IP packets. [ABSTRACT FROM AUTHOR]

A new mobile multimedia broadcasting service using a geostationary satellite was launched on May 2005 in Korea. The Satellite Digital Multimedia Broadcasting (S-DMB) system provides high quality audio, video and data broadcasting services to handheld and mobile receivers. S-DMB is a personal digital media which can provide bidirectional and interactive services via the convergent platform of broadcasting and communication. At present, TU Media, the only S-DMB service provider in Korea, provides 15 TV channels, 19 audio channels, and 3 data channels. The number of subscribers is about 890,000 by Nov. 2006. Thousands of low power gap fillers (repeaters) have been installed in the shadowed or blocked reception areas in the metropolitan Seoul. This paper presents the system requirements, standards and specifications, architecture, and service status of S-DMB in Korea. Comparisons with other satellite broadcasting systems and the services are also presented. Link budget analysis on the direct path down-link (satellite to receivers) and relay path feeder link (gap fillers to receivers) are carried out in order to ensure the satisfactory QoS. [ABSTRACT FROM AUTHOR]

This paper contributes to the studies for long-term evolution (LTE) deployment into the ultrahigh-frequency (UHF) broadcasting spectrum (470–790 MHz) utilizing the supplemental downlink (SDL) concept and its coexistence with the digital terrestrial Television (DTT) service. The performed real and practical coexistence scenario studies were based on the modeling and simulation of the LTE and DTT systems in order to assess potential interference between systems and the availability of the spectrum for the LTE SDL services. Simulations were aligned with the scenarios and assumptions agreed to in the European regulation complemented with real case study parameters from Finland: the early adopter of the digital dividend II. The results lead to some conclusions about the LTE SDL-DTT coexistence and indicated availability of the complementary LTE SDL services on the lower UHF spectrum. Flexible use of the UHF band aims to increase the efficiency of spectrum use in delivering fast growing and converging mobile broadband, media, and TV content to meet the changing consumer needs. Simulated scenarios can be utilized by regulation and standardization forums for studying the future of UHF spectrum and LTE broadcasting evolution in mobile communications toward fifth-generation (5G). [ABSTRACT FROM AUTHOR]

Network coding has been successfully used in the past for efficient broadcasting in wireless multi-hop networks. Two coding approaches are suitable for mobile networks; random linear network coding (RLNC) and XOR-based coding. In this paper, we focus on the problem of multiple source broadcasting in mobile ad hoc networks. We make the observation that RLNC provides increased resilience to packet losses compared with XOR-based coding. We develop an analytical model that justifies our intuition. However, the model also reveals that combining RLNC with probabilistic forwarding, which is the approach taken in the literature, may significantly impact RLNC’s performance. Therefore, we take the novel approach to combine RLNC with a deterministic broadcasting algorithm in order to prune transmissions. More specifically, we propose a connected dominating set-based algorithm that works in synergy with RLNC on the “packet generation level.” Since managing packet generations is a key issue in RLNC, we propose a distributed scheme, which is also suitable for mobile environments and does not compromise the coding efficiency. We show that the proposed algorithm outperforms XOR-based as well as RLNC-based schemes even when global knowledge is used for managing packet generations. [ABSTRACT FROM AUTHOR]

While terrestrial mobile multimedia broadcasting presents an exciting opportunity for both innovation and convergence to provide multimedia services in new operating environments, it remains a challenge to locate frequency spectrum in which to deploy these applications. The fact is that the frequencies suitable for such applications in a mobile environment are already heavily encumbered, and it is difficult to locate bands that are harmonized, even on a regional basis. Nonetheless, there are also opportunities for new mobile multimedia broadcasting applications, given the transition to technologies that more efficiently utilize spectrum, such as in the case of the analog to digital television transition. [ABSTRACT FROM AUTHOR]