State-of-the-art in Power Line Communications: from the Applications to the Medium

In recent decades, power line communication has attracted considerable attention from the research community and industry, as well as from regulatory and standardization bodies. In this article we provide an overview of both narrowband and broadband systems, covering potential applications, regulatory and standardization efforts and recent research advancements in channel characterization, physical layer performance, medium access and higher layer specifications and evaluations. We also identify areas of current and further study that will enable the continued success of power line communication technology.Comment: 19 pages, 12 figures. Accepted for publication, IEEE Journal on Selected Areas in Communications. Special Issue on Power Line Communications and its Integration with the Networking Ecosystem. 201

CellTV - on the Benefit of TV Distribution over Cellular Networks A Case Study

As mobile IP-access is becoming the dominant technology for providing wireless services, the demand for more spectrum for this type of access is increasing rapidly. Since IP-access can be used for all types of services, instead of a plethora of dedicated, single-service systems, there is a significant potential to make spectrum use more efficient. In this paper, the feasibility and potential benefit of replacing the current terrestrial UHF TV broadcasting system with a mobile, cellular data (IP-) network is analyzed. In the cellular network, TV content would be provided as {one} of the services, here referred to as CellTV. In the investigation we consider typical Swedish rural and urban environments. We use different models for TV viewing patterns and cellular technologies as expected in the year 2020. Results of the quantitative analysis indicate that CellTV distribution can be beneficial if the TV consumption trend goes towards more specialized programming, more local contents, and more on-demand requests. Mobile cellular systems, with their flexible unicast capabilities, will be an ideal platform to provide these services. However, the results also demonstrate that CellTV is not a spectrum-efficient replacement for terrestrial TV broadcasting with current viewing patterns (i.e. a moderate number of channels with each a high numbers of viewers). In this case, it is doubtful whether the expected spectrum savings can motivate the necessary investments in upgrading cellular sites and developing advanced TV receiver required for the success of CellTV distribution.Comment: To appear on Trans. Broadcasting 201

TV White Space and Broadband Power Line Communications for Indoor High Speed Networks

Current indoor networks have growing data rate demands to satisfy high speed applications. Broadband power line communications (BPLC) and TV white space (TVWS) communications are considered as effective solutions for indoor networks. However, they encounter several challenges concerning coexistence with wireless services. In this thesis, cooperative BPLC and TVWS is investigated in the very high frequency (VHF) band, for the aim of complementing each other to deliver enhanced performance. The main contributions of the thesis are multi-folds. In the first contribution, a general statistical based path loss mapping (GSBPL) approach is proposed for modelling the path loss of indoor low voltage (i.e. 220 v) BPLC. Also, a simplification method is proposed for computing the channel transfer function, which is proved to be more general and computationally more efficient than the previous method in literature. The feasibility of the cooperation between BPLC and wireless communications is thus concluded, through comparing their corresponding path losses. In the second contribution, a general model is proposed to map the TVWS interference with the BPLC in the VHF band, through exciting antenna mode currents along low voltage BPLC cables. A new model is presented for current conversion from antenna to differential mode, which includes a general formula for the antenna mode characteristic impedance and two solutions to the formulated problem: a) a numerical solution referred to as the antenna theory numerical (ATN) approach; b) an analytical solution referred to as the enhanced TL approximation (ETLA) approach. This is the first reported work to obtain the antenna mode characteristic impedance by the antenna theory. The ETLA approach outperforms the previous frequency-independent solution and requires a reduced complexity over the ATN approach. In the third contribution, new hybrid systems utilising BPLC and TVWS are proposed in the VHF band referred to as white BPLC (WBPLC). Two cases are considered in the proposed system: a) point-to-point WBPLC multiple-input multiple-output (MIMO) system, where a power allocation algorithm and an iterative precoding technique are proposed to maximise the ergodic capacity, subject to the constraints of total power and interference limit at the TV primary user (PU) receiver (Rx); b) point-to-multipoint WBPLC MIMO system. The overall network downlink capacity maximisation problem is investigated, using an efficient algorithm for power and subcarrier allocation among different users

SGD Frequency-Domain Space-Frequency Semiblind Multiuser Receiver with an Adaptive Optimal Mixing Parameter

A novel stochastic gradient descent frequency-domain (FD) space-frequency (SF) semiblind multiuser receiver with an adaptive optimal mixing parameter is proposed to improve performance of FD semiblind multiuser receivers with a fixed mixing parameters and reduces computational complexity of suboptimal FD semiblind multiuser receivers in SFBC downlink MIMO MC-CDMA systems where various numbers of users exist. The receiver exploits an adaptive mixing parameter to mix information ratio between the training-based mode and the blind-based mode. Analytical results prove that the optimal mixing parameter value relies on power and number of active loaded users existing in the system. Computer simulation results show that when the mixing parameter is adapted closely to the optimal mixing parameter value, the performance of the receiver outperforms existing FD SF adaptive step-size (AS) LMS semiblind based with a fixed mixing parameter and conventional FD SF AS-LMS training-based multiuser receivers in the MSE, SER and signal to interference plus noise ratio in both static and dynamic environments

Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges

With the rapid development of marine activities, there has been an increasing number of maritime mobile terminals, as well as a growing demand for high-speed and ultra-reliable maritime communications to keep them connected. Traditionally, the maritime Internet of Things (IoT) is enabled by maritime satellites. However, satellites are seriously restricted by their high latency and relatively low data rate. As an alternative, shore & island-based base stations (BSs) can be built to extend the coverage of terrestrial networks using fourth-generation (4G), fifth-generation (5G), and beyond 5G services. Unmanned aerial vehicles can also be exploited to serve as aerial maritime BSs. Despite of all these approaches, there are still open issues for an efficient maritime communication network (MCN). For example, due to the complicated electromagnetic propagation environment, the limited geometrically available BS sites, and rigorous service demands from mission-critical applications, conventional communication and networking theories and methods should be tailored for maritime scenarios. Towards this end, we provide a survey on the demand for maritime communications, the state-of-the-art MCNs, and key technologies for enhancing transmission efficiency, extending network coverage, and provisioning maritime-specific services. Future challenges in developing an environment-aware, service-driven, and integrated satellite-air-ground MCN to be smart enough to utilize external auxiliary information, e.g., sea state and atmosphere conditions, are also discussed