Stefan Nerreter

513 Mbit/s Visible Light Communications Link Based on DMT-Modulation of a White LED

We report a visible-light wireless point-to-point communication link operating at 513 Mbit/s gross transmission rate (net Mbit/s). The bit-error ratio of the uncoded data was smaller than for an illumination level of lx. The link was based on a commercial thin-film high-power phosphorescent white LED, an avalanche photo diode, and off-line signal processing of discrete multitone signals. Quadrature-amplitude modulation, bit- and power-loading, as well as symmetrical clipping were successfully employed in pushing the gross transmission rate beyond 500 Mbit/s. Adaptation of the clipping level increased the data rate only by 2%, while simulations predicted an enhancement of 20%. Obstacles towards higher data rates as well as potential remedies are discussed. We predicted that data rates of over 1 Gbit/s can be achieved with the same setup and under the same experimental conditions if these obstacles are overcome.

Visible-light communication system enabling 73 Mb/s data streaming

The hOME Gigabit Access (OMEGA) home-area-network project aims at bridging the gap between home and access network and providing Gb/s connectivity to users. The project considers a combination of various technologies such as radio-frequency and wireless optical links operating at infrared and visible wavelengths. When combined with power-line communications (PLC), this enables a home backbone that meets the projects “without new wires” vision. A technology-independent MAC layer will control this network and provide services as well as connectivity to any number of devices the user wishes to connect to in any room of a house/apartment. In order to make this vision come true, substantial progress had to be achieved in the fields of optical wireless physical layer development and data-link-layer protocol design. This paper reports an experimental demonstration of an indoor visible-light wireless link including a MAC layer protocol adapted to optical wireless communications systems. The system operates at 84 Mb/s broadcast and was successfully used to transmit three highdefinition video streams.

Optical wireless communications for broadband access in home area networks

As a part of the EU-FP7 R&D programme, the OMEGA project (hOME Gigabit Access) aims at bridging the gap between mobile broadband terminals and the wired backbone network in homes. To provide Gb/s connectivity a combination of various technologies is considered. Beside radio frequencies, the wireless links will use infrared and visible light. Combined with power-line communications this enables a home area network (HAN) that meets the vision of broadband home networking dasiawithout new wirespsila. A technology-independent MAC layer is foreseen to control such network and to provide services as well as connectivity to any device the user wishes to connect. Moreover, this MAC layer should allow the service to follow the user from device to device in any room of a building /apartment. The contribution presents ideas and approaches for broadband optical wireless (OW) communications using infrared Gb/s hotspots and 100 Mb/s information broadcasting by means of interior lighting based on white-light LEDs. Important issues concerning the physical layer are discussed.

Hybrid wireless optics (HWO): Building the next-generation home network

Gigabit home access networks (HANs) are a pivotal technology to be developed if the European Union (EU) Vision of the Future Internet is to be realised. Consumers will require such HANs to be simple to install, without any new wires, and easy enough to use so that information services running on the HAN will be ldquojust another utility,rdquo as, for instance, electricity, water and gas are today. The hOME Gigabit Access (OMEGA) HAN project [1] aims at bridging the gap between home and access network, providing Gbit/s connectivity to users. The project considers a combination of various technologies such as radio frequency (RF) and free-space or wireless optical links (FSO - operating at infrared and visible wavelengths) in order to meet user demands and provide wireless connectivity within and the home and its surroundings. When combined with power-line communications this enables a home backbone that meets the ldquowithout new wiresrdquo vision. A technology-independent MAC layer will control this network and provide services as well as connectivity to any number of devices the user wishes to connect to it in any room in a house/apartment, and further, this MAC layer will allow the service to follow the user from device to device. In order to make this vision come true, substantial progress is required in the fields of optical-wireless physical layers, in protocol design, and in system architecture.

Advances and prospects in high-speed information broadcast using phosphorescent white-light LEDs

In this paper, we present experimental results on optical wireless transmission using commercially available phosphorescent white-light LEDs. To the best of our knowledge, we demonstrate for the first time visible-light links operating at transmission rates up to 200 Mb/s over typical room distances and at reasonable bit-error-ratios. The experiments were performed using optical filtering at the receiver and on-off-keying as well as discrete multi-tone modulation combined with off-line processing. Moreover, we briefly discuss fields of application, the status of standardization and topics for further research.

Home access networks using optical wireless transmission

Fibre to the home and other dasialast-milepsila transmission technologies provide end-user data rates of at least 100 of Mbit/s. These technologies are currently deployed around the world, and in the short term gigabit-class home access networks will be required if this capacity is to be fully used, and new services are to be developed. In order to meet this goal, the Home Gigabit Access Project (OMEGA, EU FP 7-1) aims at a range of transmission techniques and intelligent control. A significant part of this effort is devoted to two areas of optical wireless communications.

Wireless optical network for a home network

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.

Video broadcast via a lamp

We report the implementation of a real-time visible-light link, based on discrete multitone modulation of a high-brightness LED. Parallel transmission of three high-definition video streams was also demonstrated.