It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

On the capacity of a cellular CDMA system

Advances in wireless communication technologies, such as wearable and implantable biosensors, along with recent developments in the embedded computing area are enabling the design, development, and implementation of body area networks. This class of networks is paving the way for the deployment of innovative healthcare monitoring applications. In the past few years, much of the research in the area of body area networks has focused on issues related to wireless sensor designs, sensor miniaturization, low-power sensor circuitry, signal processing, and communications protocols. In this paper, we present an overview of body area networks, and a discussion of BAN communications types and their related issues. We provide a detailed investigation of sensor devices, physical layer, data link layer, and radio technology aspects of BAN research. We also present a taxonomy of BAN projects that have been introduced/proposed to date. Finally, we highlight some of the design challenges and open issues that still need to be addressed to make BANs truly ubiquitous for a wide range of applications.

Body Area Networks: A Survey

The solid-state lighting is revolutionizing the indoor illumination. Current incandescent and fluorescent lamps are being replaced by the LEDs at a rapid pace. Apart from extremely high energy efficiency, the LEDs have other advantages such as longer lifespan, lower heat generation, and improved color rendering without using harmful chemicals. One additional benefit of LEDs is that they are capable of switching to different light intensity at a very fast rate. This functionality has given rise to a novel communication technology (known as visible light communication—VLC) where LED luminaires can be used for high speed data transfer. This survey provides a technology overview and review of existing literature of visible light communication and sensing. This paper provides a detailed survey of 1) visible light communication system and characteristics of its various components such as transmitter and receiver; 2) physical layer properties of visible light communication channel, modulation methods, and MIMO techniques; 3) medium access techniques; 4) system design and programmable platforms; and 5) visible light sensing and application such as indoor localization, gesture recognition, screen-camera communication, and vehicular networking. We also outline important challenges that need to be addressed in order to design high-speed mobile networks using visible light communication.

Visible Light Communication, Networking, and Sensing: A Survey, Potential and Challenges

The days where swarms of unmanned aerial vehicles (UAVs) will occupy our skies are fast approaching due to the introduction of cost-efficient and reliable small aerial vehicles and the increasing demand for use of such vehicles in a plethora of civil applications. Governments and industry alike have been heavily investing in the development of UAVs. As such it is important to understand the characteristics of networks with UAVs to enable the incorporation of multiple, coordinated aerial vehicles into the air traffic in a reliable and safe manner. To this end, this survey reports the characteristics and requirements of UAV networks for envisioned civil applications over the period 2000–2015 from a communications and networking viewpoint. We survey and quantify quality-of-service requirements, network-relevant mission parameters, data requirements, and the minimum data to be transmitted over the network. Furthermore, we elaborate on general networking related requirements such as connectivity, adaptability, safety, privacy, security, and scalability. We also report experimental results from many projects and investigate the suitability of existing communication technologies for supporting reliable aerial networking.

Survey on Unmanned Aerial Vehicle Networks for Civil Applications: A Communications Viewpoint

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An Introduction To The Theory Of Point Processes

This paper proposes a novel data acquisition framework in sensor networks using an unmanned aerial vehicle (UAV) with the goal of increasing the efficiency of the data gathering efforts. To maximize the system throughput, we introduce a priority-based frame selection scheme to suppress the number of redundant data transmissions between sensor nodes and the UAV. Toward this goal, we classify the nodes inside the UAV's coverage area into different frames according to their locations. Taking advantage of the mobility of the UAV, we assign different transmission priorities to nodes in different frames. To do that, we introduce an adjustment to the contention window value used in IEEE 802.11 MAC, thereby defining a lower contention window range to the frame with higher priority (urgent area) and a higher contention window range to the frame with lower priority (less important area). The proposed framework leads to a reduction in packet collisions and, at the same time, minimizes the packet loss originated from nodes in the rear-side of the UAV when the UAV moves in the forward direction. To optimize the networks' energy consumption, we present a novel routing protocol based on the aforementioned framework. By leveraging the proposed framework and routing algorithm, we aim to reduce the transmission distances between senders and receivers. A shorter distance leads to better channel quality and energy savings, as is verified by our simulation studies and results.

Priority-Based Data Gathering Framework in UAV-Assisted Wireless Sensor Networks

Stratospheric platforms have been recently proposed as a new wireless infrastructure for realizing the next generation of communication systems. To provide high quality services, an investigation of the wireless stratospheric platform channel is essential. This paper proposes a definition and describes an analysis of the wireless channel for the link between stratospheric platforms and terrestrial mobile users based on an experiment in a semi-urban environment. Narrowband channel characteristics are presented in terms of Ricean factor (K factor) and local mean received power over a wide range of elevation angles ranging from 10° to 90°. Finally, we evaluated average bit error probability based on the proposed channel model to examine the channel, performance. For the environment in which the measurements were conducted, we find that elevation angles greater than 40° yield better performance.

Channel Characterization and Performance Evaluation of Mobile Communication Employing Stratospheric Platforms

Body area networks (BAN) will become increasingly important in the future personal communication systems. We believe that intra-body communications (IBC) based on near field electromagnetic waves is a suitable solution for BAN. This paper presents experimental measurements of the frequency and time domain responses in order to investigate the transmission characteristics of the human body as a conductor of low power high frequency radio signals (up to 3GHz). In the measurements, several distances between transmitter and receiver (up to a long distance from the head to the foot) and six test people (to study the possible variation results due to physiological body effects) have been considered. Besides analyzing the intra-body channel response, we also aim to define a suitable frequency range for IBC. Finally, this paper also presents an initial evaluation study of several digital modulation schemes in order to investigate the optimal technique for IBC.

Propagation characteristics of intra-body communications for body area networks

Intra-body communications is becoming a promising solution for body area networks with a lot of interesting potential applications towards a ubiquitous communication world. Our research is based on the near-field radio, wherein electromagnetic radio signals are transmitted through the human body from a transmitter to a receiver. In contrast with current studies, we aim to study the transmission characteristics of the human body as a conductor of radio signals with higher frequency carriers (up to 1400 MHz) in order to find an optimal frequency range for implementing, at last, broadband intra-body communications with high data rates. To achieve our first goal, we carry out experiments where we investigate the delay time profile and the attenuation of the received signal.

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A study on the transmission characteristics of the human body towards broadband intra-body communications

In this paper, a new MAC protocol is proposed for the communication system between a large wireless sensors network (WSN) and a small unmanned aerial vehicle (UAV). In this system, the direct communication between the sensor and the UAV replaces the conventional multi hop communication among the sensor nodes. The key factor of this system is to ensure the concurrent transmission from the sensor to the UAV. The idea is to divide the active sensors into several sub groups which each is assigned with a proper priority via the proposed PFS scheme (Prioritized Frame Selection). For effective reason, TDMA has been validated for those multiple data transmissions in each sub group. However, the number of sensors is unknown which is a challenging of this scheme in the first flight. This problem has been solved by another proposed FRA scheme (Frame based Random Access). The findings of this MAC protocol are the optimal number of sub groups, data packet size, and altitude of the UAV under an acceptable ratio of packet error rate (PER) and the number of sensors in the network.

Shigeru Shimamoto

Papers

Priority-Based Data Gathering Framework in UAV-Assisted Wireless Sensor Networks

Channel Characterization and Performance Evaluation of Mobile Communication Employing Stratospheric Platforms

Propagation characteristics of intra-body communications for body area networks

A study on the transmission characteristics of the human body towards broadband intra-body communications

Highly reliable communication protocol for WSN-UAV system employing TDMA and PFS scheme