The information networks of the future will consist of an all-optical core, with wireless access technologies wherever possible. The fibre networks are extending their reach rapidly, and will further extend to individual spaces within homes and office buildings. The data traffic on networks and the demand for wireless services are also growing exponentially and the nature of services is also evolving with rapid increase in the number of devices. A new generation of 3D displays, with the ability to create Virtual Reality (VR) environments, is being launched. VR technology places significant demands on bandwidth, latency, positioning and mobility. One challenge addressed by our European collaborative project WORTECS is the development of an optical wireless system able to deliver ultra-high throughput (up to Tbps). The first demonstrator focuses on a high density network that can provide > 1 Gbps per user with multi user, but has the potential to provide Tbps per indoor environment. The second demonstrator focuses on ultra-high data rate links with a novel fibre-optical wireless-fibre approach to create Tbps capable links. VR is targeted as a demanding application, however, other applications include wireless data centers and aircraft cabins. In this paper, after introduction on the demand for wireless Terabit/s communication, we will focus on VR use case and the need for multi-Gigabit/s data rates. Then we will present the challenges for the project and propose new optical wireless system architecture and system engineering associated to new approach in space and frequency diversity with OFDM and adaptive bit rate for VR.
For over a century and Mr. Guglielmo Marconi invention, systems using radio waves have controlled over wireless telecommunication solutions; from Amplitude Modulation (AM) radio products to satellite communications for instance. But beyond an increasingly negative opinion face to radio waves and radio spectrum availability more and more reduced; there is an unprecedented opportunity with LED installation in displays and lighting to provide optical wireless communication solutions. As a result, technologically mature solutions are already commercially available for services such as Location Based Services (LBS), broadcast diffusion or Intelligent Transport Services (ITS). Pending finalization of the standard review process IEEE 802.15.7 r1, our paper presents the results of the European collaborative project named "ACEMIND". It offers an indoor bilateral optical wireless communication prototype having the following characteristics: use of the existing electrical infrastructure, through judicious combination with Light Fidelity (LiFi), Power Line Communication (PLC) and Ethernet to reduce the implementation cost. We propose a bilateral optical wireless communication even when the light is switched off by using Visible Light Communication (VLC) and Infra-Red Communication (IRC) combined to a remote optical switch. Dimensionally optimized LiFi module is presented in order to offer the possibility for integration inside a laptop. Finally, there is operational mechanism implementation such as OFDM/DMT to increase throughput. After the introduction, we will present the results of a market study from Orange Labs customers about their opinion on LiFi components. Then we will detail the LiFi prototype, from the physical layer aspect to MAC layer before concluding on commercial development prospects.
In this paper we describe an angle diversity optical wireless system that operates at 280Mbits/s and provides
bidirectional data transmission over a wide coverage area. The system uses commercially available components and
operates at a wavelength of 860nm. Three terminals, each using seven transmitter and receiver channels were
implemented, and the system was successfully tested in a wide range of different conditions. Implementation challenges,
design and performance are also discussed, together with future directions for this work.
The European project "hOME Gigabit Access Network" (OMEGA) targeted various wireless and wired
solutions for 1 Gbit/s connectivity in Home Area Networks (HANs). One objective was to evaluate the suitability of
optical wireless technologies in two spectral regions: visible light (visible-light communications - VLC) and near
infrared (infrared communications - IRC). Several demonstrators have been built, all of them largely relying on overthe-
shelf components. The demonstrators included a "wide-area" VLC broadcast link based on LED ceiling lighting and
a laser-based high-data-rate "wide-area" IRC prototype.
In this paper we discuss an adapted optical-wireless media-access-control (OWMAC) sublayer, which was
developed and implemented during the project. It is suitable for both IRC and VLC. The VLC prototype is based on
DMT signal processing and provides broadcasting at ~ 100 Mbit/s over an area of approximately 5 m2. The IRC
prototype provides ~300 Mbit/s half-duplex communication over an area of approximately 30 m2. The IRC mesh
network, composed of one base station and two terminals, is based on OOK modulation, multi-sector transceivers, and
an ultra-fast sector switch.
After a brief discussion about the design of the optical-wireless data link layer and the optical-wireless switch
(OWS) card, we address the card development and implementation. We also present applications for the VLC and IRC
prototypes and measurement results regarding the MAC layer.
High-speed optical wireless systems are challenging to implement, due to limitations in available components, and
implementation of the necessary high speed electronics. In this paper we report on the development of a gigabit/s class
infrared indoor optical wireless system that uses commercially available components. System challenges and design
choices are discussed together with details of demonstrator construction. Results from the implementation of a
demonstration system are also detailed, together with a discussion of how this might scale in the future.
During the European collaborative project
OMEGA, two optical-wireless prototypes have been
developed. The first prototype operates in the near-infrared
spectral region and features Giga Ethernet connectivity, a
simple transceiver architecture due to the use of on-off
keying, a multi-sector transceiver, and an ultra-fast switch
for sector-to-sector hand over. This full-duplex system,
composed by one base station and one module, transmits
data on three meters.
The second prototype is a visible-light-communications
system based on DMT signal processing and an adapted
MAC sublayer. Data rates around to 100 Mb/s at the
physical layer are achieved. This broadcast system,
composed also by one base station and one module, transmits
data up to two meters.
In this paper we present the adapted optical wireless
media-access-control sublayer protocol for visible-light
communications. This protocol accommodates link
adaptation from 128 Mb/s to 1024 Mb/s with multi-sector
coverage, and half-duplex or full-duplex transmission.
The optical wireless system is a promising solution for increasing the available communication bandwidth
within a room. This technology can give a very high-speed communication between devices and becomes a good
alternative with respect to radio systems. For both technologies, the architecture is similar: a base station is installed
to cover zones and transmit data with a defined quality of service. A device may be connected to the Wireless Local
Area Network (WLAN) with an adapter that emits and receives on this network.
The wireless optical technology has advantageous specific characteristics, such as: secure data transmission,
immunity, high data rate, wavelength re-use. Nevertheless, the optical system may have a limit on the network
management aspect and link budget. The scope of this paper is to present a prototype developed during a
collaborative project. This prototype uses a Giga Ethernet chip and components in the 1550 nm band. Based on OOK
modulation, the prototype is fully compatible with the direct conversion of fibre-based Giga-Ethernet to an analogue
free space version. Moreover, it also proposes a new class 1 high power emission solution with 30 dBm on 45° HP
(Half Power) angle and a new large Field Of View (FOV) module on the reception side. This full duplex system,
composed by one Base station and two Modules, transmits data on, at least, one meter. The document will present
the prototype characteristics with testbed and experimentation results.
As a part of the EU-FP7 R&D programme, the OMEGA project (hOME Gigabit Access) aims at bridging the gap
between wireless terminals and wired backbone network in homes, providing high bit rate connectivity to users. Beside
radio frequencies, the wireless links will use Optical Wireless (OW) communications. To guarantee high performance
and quality of service in real-time, our system needs techniques to approximate the Bit Error Probability (BEP) with a
reasonable training sequence. Traditionally, the BEP is approximated by the Bit Error Rate (BER) measured by counting
the number of errors within a given sequence of bits. For small BERs, required sequences are huge and may prevent real-time
estimation. In this paper, methods to estimate BER using Probability Density Function (PDF) estimation are
presented. Two a posteriori techniques based on Parzen estimator or constrained Gram-Charlier series expansion are
adapted and applied to OW communications. Aided by simulations, comparison is done over experimental optical
channels. We show that, for different scenarios, such as optical multipath distortion or a well designed Code Division
Multiple Access (CDMA) system, this approach outperforms the counting method and yields to better results with a
relatively small training sequence.
The Free Space Optic (FSO) communication is a daily reality used by an increasing number of companies.
For indoor environment, optical wireless communication becomes a good alternative with respect to radio proposals.
For both technologies, the architecture is similar: emission/reception base station (Gateway or Bridge) are installed to
cover zones, which are defined to ensure a quality of service. The customers may be connected to the Wireless Local
Area Network (WLAN) with an adapter or module that emits and receives on this network.
But due to its specific characteristics, wireless optical technology could present important advantages such as:
Transmitted data security, medical immunity, high data rate, etc... Nevertheless, the optical system may have a limit
on the network management aspect and link budget. The scope of this paper is to present a proposal at crossroads
between optical fibre telecom system and data processing.
In this document, we will present a prototype developed in Brittany during a regional collaborative project (Techim@ges). In order to answer to the management aspect and the link budget, this prototype uses an optical multiplexing technique in 1550 nm band: the Wavelength Division Multiple Access (WDMA). Moreover it also proposes a new class 1 high power emission solution. This full duplex system transmits these various wavelengths in free space, by using optical Multiplexer/Demultiplexer and optical modules. Each module has a defined and personal wavelength associated to the terminal identification (addresses MAC or IP). This approach permits a data rate at a minimum of a ten's Mbit/s per customer and potentially hundred Mbps for a line of sight system. The application field for the achieved and proposed prototype is potentially investigated from WLAN to WPAN.
Wireless networks are currently replacing connection cables via radio, visible or infrared waves.
Modules and base systems are installed to cover zones in relation to a quality of service and availability.
There are technological radio solutions: Bluetooth, WiFi, UWB and optics constituted by infrared or visible
Optic technology has important advantages: Transmitted data security, radio and medical immunity,
etc. Nevertheless, optical systems seem to present a limit because this is basically a line of sight solution
and the network management is based on only one wavelength with several users.
The solution suggested, in the scope of this document, is to transmit various wavelengths in free
space, using optical Multiplexer/Demultiplexer and optical modules, which are compatible in wavelength.
Each Emission/reception module could have a defined and personal wavelength, with a link with
the terminal identification (MAC address for instance).
This approach can improve and give a full duplex data rate with a minimum of a dozen Mbps per
user for broadcasting.
The application field for the suggested system is potentially included in the following network
types: Optic WLAN and Optic WDAN.
Free-space optical (FSO) communication links constitute an alternative option to radio relay links and to optical cables facing growth needs in high-speed telecommunications (abundance of unregulated bandwidth, rapid installation, availability of low-cost optical components offering a high data rate, etc). Their operationalisation requires a good knowledge of the atmospheric effects which can negatively affect role propagation and the availability of the link, and thus to the quality of service (QoS). Better control of these phenomena will allow for the evaluation of system performance and thus assist with improving reliability.
The aim of this paper is to compare the behavior of a FSO link located in south of France (Toulouse: with the following parameters: around 270 meters (0.2 mile) long, 34 Mbps data rate, 850 nm wavelength and PDH frame) with airport meteorological data. The second aim of the paper is to assess in-house FSO quality of service prediction software, through comparing simulations with the optical link data and the weather data. The analysis uses in-house software FSO quality of service prediction software ("FSO Prediction") developed by France Telecom Research & Development, which integrates news fog fading equations (compare to Kim & al.) and includes multiple effects (geometrical attenuation, atmospheric fading, rain, snow, scintillation and refraction attenuation due to atmospheric turbulence, optical mispointing attenuation). The FSO link field trial, intended to enable the demonstration and evaluation of these different effects, is described; and preliminary results of the field trial, from December 2004 to May 2005, are then presented.
Currently the wireless networks are replacing the connection cables via radio or infrared waves. Emission/reception terminals are installed to cover zones in relation with a quality of service. Thus users can be connected to the local area network thanks to an adapter that emits and receives on this network. There are technological radio solutions : Bluetooth, WiFi, and optics constituted by an infrared base and modules. Infrared technology has important advantages: Transmitted data security, radio and medical immunity, etc. Nevertheless, the optical systems seem to present a limit because the network management is based on only one wavelength and several users. The solution suggested, scope of this document, is at a crossroads with the telecoms with optical fibre, optics in free space and data processing domains. Indeed, it is a question, of using WDM technology and transmitting these various wavelengths in free space, using optical Multiplexer/Demultiplexer and optical modules, which are compatible in wavelength. Each mission/reception module has a defined and personal wavelength, with a link with the terminal identification (addresses MAC or IP). This approach has full duplex data rate for a minimum of a dozen Mbps per user for a broadcasting, and hundred Mbps for a line of sight system. The application field for the suggested system is potentially included in the following networks types: WirLAN, WirDAN or WirPAN.
Free space Optical links (FSO) in visible and infrared wavelengths constitute an interesting alternative to new transmission channels for cordless phone, data-processing networks and high definition television. One finds a choice of varied manufacturers and they propose products whose performances are characterized by a raised rate of transmission, from 2 Mbps to 10 Gbps. But the announced ranges are very important, from 100 to 10 000 meters, in spite of the fact that many manufacturers try to indicate the possible ranges according to time, these indications completely miss standardization and are hardly exploitable because, generally, it is very difficult to know the percentage of time during which a value is reached or exceeded. Availability and reliability of a FSO link depend on used systems but also on climatic and atmospheric parameters such as rain, snow or fog. It is the purpose of our study. Its finality is software which integrates: - Results of a bibliographical search (geometrical, aerosols, rain, snow, fog, scintillation, and environment solar light attenuation), - European integrated surface weather data, hour per hour, over several years (1995-1999). The result is the presentation of the Quality of Service Light version software which allows predicting; starting from the data of equipment (power, wavelength, receiver sensibility), geographical situation of a site in Europe (geographical coordinates, altitude, height/ground) and climatic and atmospheric parameter (relative humidity, ground rugosity, albedo, solar radiation, etc) the availability of a FSO link for the following period (year, the most unfavourable month, 8am to 8pm period and 8 pm to 8 am period. The interruption probabilities for each type of attenuation are also mentioned (aerosols, scintillation, ambient solar light, rain, snow, etc).
The atmospheric optical links (FSO) in visible and infrared wavelengths constitute an interesting alternative to creation of new transmission channels for the cordless phone, data-processing networks and high definition television. One finds a choice of varied manufacturers and they propose products whose performances are characterized by a raised rate of transmission, from 2 Mbps to 10 Gbps. But the announced ranges are very important, from 100 to 10,000 meters, in spite of the fact that many manufacturers try to indicate the possible ranges according to time, these indications completely miss standardization and are hardly exploitable because, generally, it is very difficult to know the percentage of time during which a value is reached or exceeded. Availability and reliability of a FSO link depend on used systems but also on climatic and atmospheric parameters such as rain, snow or fog. Library search underlined the lack of reliable data to be able to lay down, in a precise way, the statistical availability of such links, like one usually does for the radio transmission. Before to implement an effective FSO links, we need to know their availability and their reliability. It is the purpose of our study. Its finality is a software which integrate (1) Results of a library search (geometrical attenuation, aerosols, scintillation, environment light, etc),
(2) English and French integrated surface weather data, hour per hour, over several years (1995-1999).
The result is the presentation of this software, "QoSLight" (Quality of Service Light), making it possible to predict; starting from the data of equipment (power, wavelength, receiver sensibility), geographical situation of a site in France or England (geographical coordinates, altitude, height/ground) and climatic and atmospheric parameter (relative humidity, ground rugosity, albedo, solar radiation, etc) the availability of a FSO link for the following period (year, the most unfavourable month, 8am to 8pm period and 8 am period. The interruption probabilities for each type of attenuation are also mentioned (aerosols, scintillation, ambient solar light, rain, snow, etc).