|Wireless Optical Networks|
A brief intro to Optical Wireless Communications
Optical wireless communications (OWC) is a technology that relies on optical beams to relay information wirelessly. Following some first and fundamental works of the late 70’s, OWC systems have attracted extensive research and considerable commercial deployment in a broad range of networking applications. The latest commercially available products have entered the Gb/s regime: Giga-IR from IrDA enables personal OWC at rate of >1 Gb/s while ongoing standardization efforts aim at rates of 10 Gb/s or more. In addition, 10 Gb/s Ethernet compliant outdoor systems by numerous system vendors can be found in market and even higher line rates are expected in the future.
The case for OWC relies primarily on the unique aspects of this technology. Optics is a well-established broadband technology, providing link speeds that range between 10-100 Gb/s per channel. Clearly, this capacity is not realizable by competing RF-based commercial technologies, which are currently limited to 1.25 Gb/s, and OWC are at an obvious advantage for the deployment of high rate point-to-point links. In addition, OWC provides a low cost alternative for the realization of broadband private networks (office and LAN interconnections) in heavily populated metropolitan areas. If a fiber solution is considered, the interconnection typically requires that either optical fibers are leased from a local network operator or new optical fibers are installed between customer premises. Both RF- and fiber-based solutions exhibit increased costs when compared to OWC, which simply require the deployment of roof mounted infrared transceivers. It should be also noted that, in contrast with RF systems, OWC do not require frequency licensing fees since the infrared transmission bands are unlicensed and that the only limitation is imposed by the eye-safety constraints.
The CNA research staff maintain a proven track record on Optical Wireless Communications (OWC). The group expertise focuses on two primary domains:
1) Indoor Infrared Systems
The optimal utilization of the infrared link capacity (1-10 Gb/s) calls for a detailed study, cross-layer design and innovative extension of available protocol stacks. To this end, the research group works to:
a) Independently evaluate the performance of all Giga-IR protocols (OBEX, TTP, IrLMP, IrLAP), by deriving mathematical frameworks that associate key metrics (mainly throughput and delay) with networking parameters.
b) Independently optimize the performance of Giga-IR protocols, given the developed mathematical frameworks.
c) Identify protocol interactions that affect the stack performance and perform cross-layer optimization.
2) Outdoor Systems
Outdoor OW systems are designed to achieve increased data rates and link distances, and in practical application scenarios the system designer aims to maximize the rate-distance product of the OW link. Optical transceivers are well capable of operating over 10 Gb/s but the attained rate-distance product is severely limited by the impact of the atmospheric effects on the optical beams. The research group works towards
a) The analysis and evaluation of the atmospheric impact (amplitude fading and phase steering) on the OWC link by means of stochastic models.
b) The channel equalization by means of optical components (semiconductor optical amplifiers and interferometers).
c) The development of suitable automatic repeat-request (ARQ) protocols that take into account the impairments that are induced by the atmospheric phenomena.
Some indicative publications of the group member at the area of OWC include:
1. K. Yiannopoulos, N.C. Sagias, and A.C. Boucouvalas, "Fade Mitigation Based on Semiconductor Optical Amplifiers," IEEE/OSA Journal of Lightwave Technology, vol. 31, no. 23, pp. 3621-3630, December 1, 2013.
2. K. Yiannopoulos, and A.C. Boucouvalas, "Analysis and Optimization of the Link-Layer Protocol in Gb/s Infrared Links," IET Communications, vol. 7, no. 7, pp. 652-662, May 2013.
3. K. Yiannopoulos, and A.C. Boucouvalas, "Link-Layer Buffering Requirements and Optimization of Gb/s Infrared Enabled Devices," IEEE/OSA Journal of Optical Communications and Networking, vol. 4, no. 5, pp. 663-670, September 2012.
4. D.K. Borah, A.C. Boucouvalas, C.C. Davis, S. Hranilovic, and K. Yiannopoulos, "A review of communication-oriented optical wireless systems," EURASIP Journal on Wireless Communications and Networking, 2012:91, pp. 1-28, April 2012.
5. P. Huang, A. C. Boucouvalas, "Future Personal e-Payment: IrFM," IEEE Magazine on Wireless Communications, Volume 13, Issue 1, Feb 2006 Page(s):60 – 66.
6. Pi Huang, P. Chatzimisios, A. C. Boucouvalas, "Optimising IrDA throughput by including processing time with physical layer consideration" , Optical Society of America (OSA) Journal of Optical Networking (JON), Issue: June2005, Vol. 4, No. 6, Jun, 2005.
7. V. Vitsas, A. C. Boucouvalas, "Optimisation of IrDA IrLAP Link Access protocol", IEEE Transactions on Wireless Communications, Vol. 2, No. 5, September 2003, pp. 926-938.
8. V. Vitsas, P. Barker, A. C. Boucouvalas, "IrDA Infrared Wireless Communications: Protocol Throughput Optimization", IEEE Wireless Communications Magazine: Special Issue on Optical Wireless Communications April 2003, Vol 10, Issue 2, pp. 22-29.
1. K. Yiannopoulos, N.C. Sagias, and A.C. Boucouvalas, ”SOA Nonlinear Ampliﬁcation: A Promising Fade Mitigation Technique for Optical Wireless Systems,” IEEE Wireless Communications and Networking Conference 2014 (accepted).
2. A.C. Boucouvalas, N. Sagias and K. Yiannopoulos, “First Order Statistics of Semiconductor Optical Amplifier Assisted Optical Wireless Systems under Lognormal Fading,” International Workshop on Optical Wireless . 2013.
3. K. Yiannopoulos, and A.C. Boucouvalas, "Alternatives for the Implementation and Efficiency Optimization of 10 Gb/s Short Range Infrared Links," in Proc. Communication Systems, Networks and Digital Signal Processing (CSNDSP) 2012, pp. 1-4.
4. A. C. Boucouvalas, "Reliability of Indoor and short range FSO", ICTON 2005, Barchelona, Spain, Session PONEXT II-FSO, paper Tu B3.1, 3-5 July 2005 (invited paper).
5. Pi Huang, A. C. Boucouvalas, "Modelling IrSC: Proposal Options and Performance Analysis", IEE Proceedings Circuits, Devices & Systems, Dec, 2005.
6. P. Huang, A. C. Boucouvalas, "Modelling IrDA Transport Layer TinyTP," CSNDSP 2004, Newcastle upon Tyne University, 20-22 July 2004.
7. P. Huang, A. C. Boucouvalas, "OBEX Performance Evaluation and parameter Optimization for High Speed IrDA Links", IEEE ICC 2004, Paris, ISBN: 0-7803-8534-9, Volume: 7, pp. 3849 – 3853.
8. V. Vitsas, A. C. Boucouvalas, "IrDA IrLAP Protocol Performance and Optimum Link Layer Parameters forMaximum Throughput", IEEE GLOBECOM 2002, 17-21st November 2002, Taipei, ROC, Session HSN-01, Vol. 3, pp. 2270-2275.
|Last Updated on Wednesday, 22 January 2014 15:28|