The vision of next generation 5G wireless communications lies in providing very high data rates (typically of Gbps order), extremely low latency, manifold increase in base station capacity, and significant improvement in users’ perceived quality of service (QoS), compared to current 4G LTE networks. Ever increasing proliferation of smart devices, introduction of new emerging multimedia applications, together with an exponential rise in wireless data (multimedia) demand and usage is already creating a significant burden on existing cellular networks. 5G wireless systems, with improved data rates, capacity, latency, and QoS are expected to be the panacea of most of the current cellular networks’ problems. In this survey, we make an exhaustive review of wireless evolution toward 5G networks. We first discuss the new architectural changes associated with the radio access network (RAN) design, including air interfaces, smart antennas, cloud and heterogeneous RAN. Subsequently, we make an in-depth survey of underlying novel mm-wave physical layer technologies, encompassing new channel model estimation, directional antenna design, beamforming algorithms, and massive MIMO technologies. Next, the details of MAC layer protocols and multiplexing schemes needed to efficiently support this new physical layer are discussed. We also look into the killer applications, considered as the major driving force behind 5G. In order to understand the improved user experience, we provide highlights of new QoS, QoE, and SON features associated with the 5G evolution. For alleviating the increased network energy consumption and operating expenditure, we make a detail review on energy awareness and cost efficiency. As understanding the current status of 5G implementation is important for its eventual commercialization, we also discuss relevant field trials, drive tests, and simulation experiments. Finally, we point out major existing research issues and identify possible future research directions.

Next Generation 5G Wireless Networks: A Comprehensive Survey

The diffusion of an innovation traditionally has been defined as the process by which that innovation is “communicated through certain channels over time among the members of a social system” (Rogers, 1983, p. 5). As such, the diffusion process consists of four key elements: innovation, communication channels, time, and the social system.

New Product Diffusion Models in Marketing: A Review and Directions for Research:

Introduction to linear and nonlinear programming

Nonlinear Programming: A Unified Approach

Providing various wireless connectivities for vehicles enables the communication between vehicles and their internal and external environments. Such a connected vehicle solution is expected to be the next frontier for automotive revolution and the key to the evolution to next generation intelligent transportation systems (ITSs). Moreover, connected vehicles are also the building blocks of emerging Internet of Vehicles (IoV). Extensive research activities and numerous industrial initiatives have paved the way for the coming era of connected vehicles. In this paper, we focus on wireless technologies and potential challenges to provide vehicle-to-x connectivity. In particular, we discuss the challenges and review the state-of-the-art wireless solutions for vehicle-to-sensor, vehicle-to-vehicle, vehicle-to-Internet, and vehicle-to-road infrastructure connectivities. We also identify future research issues for building connected vehicles.

http://bbcr.uwaterloo.ca/~xshen/paper/2015/cvsac.pdf

Connected Vehicles: Solutions and Challenges

Dedicated Short-Range Communications (DSRC) has been designed to support vehicular communications. In the U.S., DSRC operates in the 5.9 GHz licensed spectrum band. Its physical (PHY) and medium access control (MAC) layers, defined in the IEEE 802.11p standard, are based on the IEEE 802.11 family of Wi-Fi standards. Vehicular communication environments differ significantly from the sparse and low-velocity nomadic use cases of a typical Wi-Fi deployment. Thus, there are many challenges to adapt Wi-Fi technologies to support the unique requirements of vehicular communications such as achieving high and reliable performance in highly mobile, often densely populated, and frequently non-line-of-sight environments. The automotive and the communications industries, academia, and governments around the world have been devoting tremendous efforts to address these challenges, and significant achievements have been made. Remaining challenges can be addressed by the future versions of DSRC. In this paper, we investigate the current technologies used by DSRC to support vehicle safety communications, analyze existing and possible DSRC performance enhancements that can be realized in the near term, and provide a few initial thoughts on the DSRC evolution path.

Vehicular Communications Using DSRC: Challenges, Enhancements, and Evolution

This paper formulates a general framework that includes and extends the existing definitions for network survivability Based on this framework, network survivability is characterized by a survivability function rather than a single-value survivability measure, and various quantities of interest can be derived from the function Examples are the expected survivability, the worst-case survivability, the r-percentile survivability, and the probability of zero survivability The survivability function is especially useful for the study of large-scale disasters For illustration, the authors derive the survivability function in closed form for a simple ring network under link failures They also discuss the general procedure for finding survivability functions for complex networks, and show that the survivability function reveals useful information about a network This framework provides a unified and practical approach to analyzing and designing highly survivable communications networks >

A framework for characterizing disaster-based network survivability

The performance of a class of asymmetric packet switch modules with channel grouping is analyzed. The switch module considered has n inputs and m outputs. A packet destined for a particular output address (out of g) needs to access only one of the r available physical output ports: m=gr. These switch modules are the key building blocks in many large multistage switch architectures. The focus is on the performance of input-buffered and output-buffered switch modules under geometrically bursty traffic. A combination of exact derivation, numerical analysis, and simulation yields the saturation throughput of input-buffered switch modules and the mean delay of the input-buffered and output-buffered switch modules. Tables and formulas useful for traffic engineering are presented. The results show that increasing the number of output ports per output address (r) can significantly improve switch performance, especially when traffic is bursty. Although output-buffered switch modules have significantly better performance than input-buffered switch modules when there are equal numbers of input and output ports, this performance difference becomes significantly smaller when the switch dimensions are asymmetric. >

Comparison of buffering strategies for asymmetric packet switch modules

The texture of the power system which govern, the interplay of reactive power and voltage is emulated by a textured model which assembles local groups of buses into a multi-leaf structure. Groups on the same leaf of the model are not coupled with each other, groups on different leaves overlap partially and are thus coupled. The paths of computational information are organized in an efficient manner and inefficient computation and information paths are eliminated, yet the computation converges to the exact solution, not an approximate one. The resulting model is ideally suited for parallel processing especially since there is no sequential component in the computation no computation overhead and (if the size of the groups and their numbers per leaf are uniform) there is no waiting time. Computation time savings of as much as 100÷1 (i.e. a hundred fold saving) were observed in experiments on steepest descent algorithms with systems of around 100 buses. Computation times also favorably compare with existing speed up techniques such as block pivoting. Computation times for common algorithms (like matrix manipulations, Newton-Raphson, linear and nonlinear programming) increase with the system size at a fast non- linear rate. The computation times remain essentially constant for the textured model in parallel processing. Thus very large computation time savings are implied on larger systems. Consequently this new model should prove to be a valuable tool for on line computations in the course of reactive power control and management.

A Textured Model for Computationally Efficient Reactive Power Control and Management

Proposes a three-stage broadband packet-switch architecture for a future central office with more than 16000 ports. The switch is constructed by interconnecting many small independent switch modules, which can be implemented using modifications of various well-studied switch fabric designs. Multiple paths are provided for each input-output pair, and the channel grouping technique is used to decrease delay and increase throughput. A datagram packet routing approach is adopted in order to eliminate the table lookup that will be required by virtual-circuit routing. Ways of guaranteeing the sequence integrity of packets are discussed. It is estimated from performance analyses that 32768-port switches can be constructed and can perform well based on switch fabrics of no more than 128 ports. >

/pdf/a-3-stage-interconnection-structure-for-very-large-packet-2zokoeclf7.pdf

K.W. Lu

Papers

Vehicular Communications Using DSRC: Challenges, Enhancements, and Evolution

A framework for characterizing disaster-based network survivability

Comparison of buffering strategies for asymmetric packet switch modules

A Textured Model for Computationally Efficient Reactive Power Control and Management

A 3-stage interconnection structure for very large packet switches