Summary:

Radio over Fiber (RoF) systems operating at millimeter-wave (mm-wave) frequencies (26-100 GHz), due to their large spectral range, are considered to be the most promising systems of realizing high speed wireless access networks. However, the limited propagation characteristics of these high frequencies lead to small cell sizes. As a consequence, a large number of remote antenna base stations (BSs) are necessary to cover an operational geographical area. Multiple BSs provide wireless connectivity to users via millimeter-wave radio links. The BSs are connected with a central office (CO) via an optical fiber access network. The CO performs the switching and routing functionalities.

Optical WDM can greatly simplify the network architecture since it allows for different BSs to the be fed by a common fiber, with different WDM channels feeding different BSs. Additionally, in order to improve radio coverage within a cell, it is essential to utilize sectorised antenna interfaces. Each sector of the antenna should be driven by an individual signal. The conjunction of subcarrier multiplexing (SCM) with WDM can simplify the network architecture, by using a specific WDM channel to feed an individual BS and different SCM channels carried on the WDM wavelength channel to drive the individual antenna sectors within the BS.\nThis project proposes an innovative RoF access network architecture which as well as incorporating a highly efficient low cost BS, allows for dynamic allocation of the network resources according to the user temporally and geographically varying traffic requirements.

For the downlink, the mm-wave signals are transmitted directly over the fiber. This approach has the advantage of a simplified BS design but is susceptible to fiber chromatic dispersion that severely limits the transmission distance. Optical Single Side Band (OSSB) modulation suppresses one of the sideband of conventional optical double sideband modulation signals increasing the spectral efficiency of the system and improving the immunity to chromatic dispersion. Additionally, OSSB allows for direct detection without phase information destruction and consequently fiber dispersion compensation in the electrical domain. This project aims at the development of OSSB modulation techniques optimized for SCM mm-wave systems.

For the realization of the uplink of a RoF system using WDM, the BSs must incorporate an optical source which is modulated by the mm-wave uplink radio signals. This approach requires a WDM optical sources and a high-speed external modulator, resulting in a substantial increase in the cost of the optoelectronics per node. This project proposes a novel low cost BS architecture based on the use of a reflective semiconductor optical amplifier (RSOA).

In the DAWN-PRAXIS XXI/2.1/TIT/1573/93, some members of this proposal team have demonstrated with success an agile optical network based on the use of a RSOA. The present proposal, based on the results of DAWN, proposes a novel low cost BS architecture which eliminates the need for the WDM source and the optical external modulator at the BS. We expect to achieve this by combining an unmodulated RF carrier with the downlink mm-wave signal and by transmitting it from the CO to the BS. At the BS, the WDM downlink mm-wave is split. One part is directed to the RSOA and the other part is photodetected. The detected signal consists of the downlink mm-wave signal and the unmodulated RF. The unmodulated RF acts as a local oscillator (LO) and is used to downconvert the uplink data to an intermediate frequency (IF), within the electrical bandwidth of the RSOA (around 1.5 GHz), and is then used to directly modulate the RSOA. This approach offers several advantages. First, it avoids the need for a stabilized laser at each BS. Second, the RSOA can be used as a modulator which accomplishes both modulation and amplification functions. Moreover, this amplification function gives additional gain and so it is possible to avoid the use of an EDFA in the system. This uplink configuration, uses for the first time, the advantages of RSOA in RoF systems and can be applied to other wireless networks such as 3G.

An important advantage of this proposal is the generation and management of the optical carriers at the CO. As well as facilitating wavelength monitoring and control it provides flexible wavelength allocation for the BSs depending on user requirements and quality of service (QoS).  BS will be fully designed and implemented and incorporated in a system demonstrator.

1.     PhD Thesis

[T5]   Paulo Almeida Ferreirinha, ‘Radio Over Fibre Systems with Support for Fixed and Mobile services,’ Universiade de Coimbra, end data 2012. Supervisor Henrique Silva.

[T2]   Vitor Vicente Madeira Lopes, ‘Sistemas de Banda Larga em Rádio sobre Fibra,’ Universidade do Algarve, end data 2013. Supervisor Paula Laurêncio & Carmo Medeiros.

[T3]   Jose Coimbra. Title: ‘IP/Optical Integration in Access Network Infrastructures: Key issues on Resource Provisioning,’  Universidade do Algarve, end data 2011. Supervisor: Noélia Correia.

[T2]   Ricardo Pedro Custodinho da Avó, ‘Wavelength Division Multiplexing Access Networks Architectures for Broadband Fiber-Wireless Networks,’  Universidade do Algarve, end data 2011. Supervisor: Carmo Medeiros.

[T1]   Álvaro Barradas,’ Quality of Service in Optical Burst Switiching Networks,’ Universidade do Algarve, completed November 2009. Supervisor: Carmo Medeiros.

2.     MSc Dissertations

[M7]  Tashi Arthur Ravach, ‘Performance Analysis of OFDM Technology on Radio-over-Fiber Systems’, 2011. Supervisor: Carmo Medeiros.

[M6]  Hugo Edgar Amorim Silva, ‘Projecto e análise do desempenho da estação base da rede rádio sobre fibra’, 2011. Supervisor: Carmo Medeiros.

[M5]  Shadrack Omondi Anyuo, ‘Dynamic Connection Provisioning in Fiber-Wireless Access Networks using Tuning-Based ROADMs,’ Universidade do Algarve, November 2010. Supervisor: Noélia Correia.

[M4]  Ivanildo Andrade Moreira Fortes, ‘Análise Comparativa das técnicas de transmissão com modulação externa ODSB,OSSB e OCS’, 2009, Supervisor: Paula Laurêncio.

[M3]  Filipe Marques Ferreira, ‘Modulation Techniques for Radio over Fiber Systems with Subcarrier Multiplexing in Millimeter Waves,’ Universidade de Coimbra, Setembro 2009. Supervisor: Henrique Silva.

[M2]  Paulo Almeida Ferreinha, ‘Optical SSB Modulators for Signal Transmission with SCM in the 30 GHz Band,‘ Universidade de Coimbra, February 2009. Supervisor: Henrique Silva.

[M1]  Dimitros Blatzios, ‘Design of microstrip filters for the base station of the Reconfigurable Radio over Fiber network (RoFnet),’ University College of London, 2008. Supervisor: Izzat Darwazeh.

3.     Invited Talks

[PC8] “Overlay Wireless Services over WDM-PON employing colorless transmitters,” presented at GROWN 2011- International Symposium on Green Radio over Fiber & All Optical Technologies for Wireless Access Networks, 2011.

[PC7] “Comparative Study of Optical Up-Conversion Schemes,"  invited presented at  at 13th International Conference on Transparent Optical Networks, Junho 2011.

[PC6] "60 GHz radio-over-fiber transmission impairments for broadband wireless signals,"  presented at 12th International Conference on Transparent Optical Networks, Junho 2010.

[PC5] “The RoFnet concept extended to WDM-PONs” presented at VII Symposium on Enabling Optical Networks and Sensors, Porto, 2010.

[PC4]  "Convergence of Optical and Millimeter-Wave Broadband Wireless Access Networks ," presented at 11th International Conference on Transparent Optical Networks, Junho 2009.

[PC3]  "Radio over fiber access network architecture employing reflective semiconductor optical amplifiers ," presented at Icton Mediterranean Winter Conference, Dezembro 2007.

4.     Journal Papers

[J10]  M. Thakur, P. Laurêncio, M.C.R. Medeiros and J. Mitchel, Optical Frequency Tripling with Improved Suppression and Sideband Selection,’  to appear in Optics Express December 2011 (Invited extended version of the paper accepted to ECOC 2011).

[J9]    R.Avó, M. Guerreiro, M.C.R. Medeiros, ‘Bidirectional transmission of IEEE 802.11g over colorless WDM-PON employing a reflective semiconductor optical amplifier,’ Microwave and Optical Technology Letters, Vol. 53, Nº 7, July 2011.

[J8]    A. L. Barradas, and M.C.R. Medeiros, ‘An Intrinsic TE Approach for End-to-end QoS Provisioning in OBS Networks Using Static Load-balanced Routing Strategies,’ Future Internet 2010, 2, pp.559-586, October 2010.

[J7]    P. Laurêncio; H. Vargues; I. Fortes; R. Avó; M. C. R. Medeiros, ‘Dispersion Robustness of Millimeter Waves Generated by Up-Conversion Strategies,’ Fiber and Integrated Optics, 294, pp. 41–452, Nov. 2010.

[J6]    A.L. Barradas and M.C.R. Medeiros, ´Pre-planned optical burst switched routing strategies considering the streamline effect,´ Photonic Network Communications, Vol. 17, No. 1, pp. 49-62, 2010.

[J5]    A.L. Barradas and M.C.R. Medeiros, ´Edge-node Deployed Routing Strategies for Load Balancing in Optical Burst Switched Networks,´ ETRI Journal, vol.31, no.1, pp.31-41, Feb. 2009.

[J4]    N. Correia, J. Coimbra and G. Schutz, ´Fault-Tolerance Planning in Multi-Radio Hybrid Wireless-Optical Broadband Access Networks,’ IEEE/OSA Journal of Optical Communications and Networking, Vol. 1, no. 7, pp. 645-654, December 2009.

[J3]    N. S. C. Correia, J. Coimbra and M. C. R. Medeiros, ´Sparse Traffic Grooming in WDM Networks Using Coarse Granularity OXCs,’ Photonic Network Communications, Vol. 17, no. 1, pp. 49-62, February 2009.

[J2]    M.C.R. Medeiros, Ricardo Avó, Paula. Laurêncio, N. S. Correia, A. Barradas, H.J.A. da Silva, I. Darwazeh, J.E. Mitchell and P.M.N. Monteiro, ´RoFnet-Reconfigurable Radio over Fiber Network Architecture Overview,’  Journal of Telecommunications and Information Technology, Issue 1, pp. 38-43, 2009.

[J1]    P. Laurêncio and M.C.R. Medeiros, ´Relative Intensity Noise in Optical Single Side Band Systems with Multiple In-Line Amplifiers: Analysis and Validation,´ Fiber and Integrated Optics, Vol. 27, nº 2, pp:78-88, 2008.

5.     Conference Papers with Proceedings

[C32] M. Thakur, P. Laurêncio, M.C.R. Medeiros and J. Mitchel, ‘Optical Frequency Tripling with Improved Suppression and Sideband Selection,’ To be presented at 37th European Conference on Optical Communications, pp. 1-4, Oct 2011.

[C31] P. Almeida, H. Silva, ‘Distribution of MB-OFDM UWB and Millimeter-Wave WPAN Signals on Hybrid FTTH Networks,’ accepted for ICUWB 2011.

[C30] P. Almeida, H. Silva, ‘Multiservices and multiband optical signal generation for hybrid access networks,’ International Conference on Optical Network Design and Modelling, ONDM, April 2011.

[C29] P. Laurêncio, I. Fortes, M. Guerreiro and M.C. R Medeiros, ‘Transmission Performance of 60 GHz Signals Generated by OSSB Upconversion,’ Eurocon 2011: The International Conference on Computer as a Tool, Vol 1 and 2 , Proceedings, vol. 35, pp. 1-4, May 2011.

[C28] R. Avó, P. Laurêncio, M. Medeiros,’Comparative Study of Optical Up-Conversion Strategies,’ ICTON 2011: Proceedings of the 13th International Conference on Transparent Optical Networks, Vol 3, pp. 1-4, 2011. (Invited paper).

[C27] R. Avó, M. Guerreiro, M. Medeiros, ‘Overlay Services Over WDM-PONS Employing Reflective Semiconductor Optical Amplifiers,’ 16th European Conference on Networks and Optical Communications (NOC/OCI 2011) Proceedings, pp. 1-4, July 2011.

[C26] G. Schütz and N. Correia, ‘A Multi-Objective Optimization Approach for Fault-Tolerance Provisioning in Multi-Radio Hybrid Wireless-Optical Broadband Access Networks,’ ACM Symposium on Applied Computing, Sierre 22-26 March 2010.

[C25] J. Coimbra, G. Schütz and N. Correia, ‘Modeling Fiber-Wireless Access Networks using Repeated Game Theory,’ European Conference on Networks and Optical Communications (NOC 2010), pp. 359-366, June 2010.

[C24] J. Coimbra, G. Schütz and N. Correia, ‘Forwarding Repeated Game for End-to-End QoS Support in Fiber-Wireless Access Networks,’  IEEE GLOBECOM, Miami 6-10 December 2010, USA.

[C23] P. Laurêncio, I. Fortes, M.C.R. Medeiros,’Study of optical up-conversion strategies based on OSSB modulation,’ 15th European Conference on Networks and Optical Communications (NOC/OCI 2010) Proceedings, pp. 239-244, 2010.

[C22] P.R.F. Rocha, I. Darwazeh and M.C. R. Medeiros, ‘Receiver Design for radio over fiber networks employing subcarrier multiplexing techniques,’15th European Conference on Networks and Optical Communications (NOC/OCI 2010) Proceedings, pp. 233-238, 2010.

[C21] Almeida, P. ; Ferreira, F. M.; Silva, H. A.; "Multiband Signal Generation for Hybrid Access Networks Using a Single External Modulator", Proc Symp. on Enabling Optical Networks - SEON, Porto, Portugal, June, 2010.

[C20] R. Avó, M. Guerreiro, M. Medeiros, ‘Experimental transmission performance evaluation of IEEE 802.11g over a PON architecture using a RSOA,’ 15th European Conference on Networks and Optical Communications (NOC/OCI 2010)Proceedings, pp. 227-232, 2010.

[C19] P. Laurêncio, H. Vargues, R. Avó, and M. Medeiros, ‘Generation and transmission of millimeter wave signals employing optical frequency quadrupling,’ International Conference onTransparent Optical Networks (ICTON) Proceedings, 2010.

[C18] R. Avó, P. Laurêncio, and M. Medeiros, ‘60 GHz radio-over-fiber transmission impairments for broadband wireless signals,’ International Conference onTransparent Optical Networks (ICTON) Proceedings, 2010.

[C17] R. Avó, P. Laurêncio and M. C. R. Medeiros, ‘Transmission performance of mm-waves on radio over fiber systems: dispersion and intermodulation issues,’ Proc. DoCEIS´10, Emerging Trends in Technological Innovation, IFIP Advances in Information and Communication Technology, Volume 314. pp. 289-296, ISBN 978-3-642-11627-8, 2010.

[C16] Alvaro L. Barradas, and Maria do Carmo R. Medeiros, ‘Simulation Model for OBS Contention Avoidance Routing Strategies,’ Proc. DoCEIS´10, Emerging Trends in Technological Innovation, IFIP Advances in Information and Communication Technology, Volume 314. pp. 281-288, ISBN 978-3-642-11627-8, 2010.

[C15] Alvaro L. Barradas, and Maria do Carmo R. Medeiros, ‘The Streamline Effect Applied to a Pre-planned OBS Routing Strategy with Continuity Constraint,’ Proc. ICN 2010, pp 279-284, Menuires 11-16 April 2010, France.

[C14] F. Ferreira, F. M. Pato, S.; J. Pedro; Silva, H. A.; ‘Microwave link for transparent protection of optical access networks’, Proc European Conf. on Networks and Optical Communications and Conf. on Optical Cabling and Infrastructure - NOC/OC, Algarve, Portugal, Vol. 1, pp. 1 - 6, June, 2010.

[C13] W. Elboushi and I. Darwazeh, ‘Design of a Microstrip Quadplexer for the RoFnet Project’ 2009 London Communications Symposium.

[C12] H. Vargues R. Avó P. Laurêncio, M.C.R. Medeiros, ‘Simulation of mm-Wave over Fiber Systems Employing Up-Conversion Using External Modulators,’ Proc International Conf. on Transparent Optical Networks - ICTON  pp-308-311, 2009.

[C11] R. Avó, P. Laurêncio and M.C.R. Medeiros, ‘mm-wave networks over optical access network architecture employing reflective semiconductor optical amplifiers: intermodulation effects,’ Proc. NOC/OC&I 2009, pp: 249-256, Valladolid, June 2009.

[C10] A.L. Barradas and M.C.R. Medeiros, ‘Analysis of path selection mechanisms in OBS networks,’ Proc. NOC/OC&I 2009, pp: 453-460, Valladolid, June 2009.

[C9] M.C.R. Medeiros, R. Avó, P. Laurêncio, et al. ‘Convergence of Optical and Millimeter-Wave Broadband Wireless Access Networks,’ Proc International Conf. on Transparent Optical Networks - ICTON  pp-192-195, 2009.

[C8]   G. Schutz and N. S. C. Correia, ‘A Heuristic for Fault-Tolerance Provisioning in Multi-Radio Hybrid Wireless-Optical Broadband Access Networks,’ IEEE 11th International Conference on Transparent Optical Networks (ICTON’09), Azores 28 June-2 July 2009, Portugal.

[C7]   R. Avó, P. Laurêncio and M. C. R. M. Medeiros, ´ Simulation of mm-Wave over Fiber Employing Optical Single Sideband Modulation Combined with Subcarrier Multiplexing´ , in Proc. International Conference on Transparent Optical Networks (ICTON)-Mediterranean Winter’08, Marakesh, 11-13 December 2008.

[C6]   A. L. Barradas and M.C.R. Medeiros, ‘Pre-planned Optical Burst Switching Routing,’ in Proc. International Conference on Transparent Optical Networks (ICTON)-Mediterranean Winter’08, invited paper, Marakesh, 11-13 December 2008.

[C5] N. S. C. Correia, J. Coimbra, and M. C. R. Medeiros, ‘A Minimization Cost Heuristic Approach for Traffic Grooming in IP-over-WDM Networks,’ International.Conference on Systems and Networks Communications, ICSNC, 26-31  Oct. 2008.

[C4]   A.L. Barradas, M.C.R. Medeiros, ‘ An OMNeT   Model for the Evaluation of OBS Routing Strategies,’ Proceedings of OMNeT   2008 (worshop on  Simutools 2008), Marseille, 3-7 March 2008.

[C3]   M. Guerreiro, A.L. Barradas , M.C.R Medeiros ‘Path Selection Strategy for OBS Networks Based on a Probabilistic Model for the Link Demands,’ Cranfield (Multi-Strand Conference, Cranfield, 6 - 7 May 2008.

[C2]   M. G. Guerreiro; Pavan, C.; A. L. B. Barradas; Pinto, A. N.; M. C. R. M. Medeiros; ‘Path Selection Strategy for Consumer Grid over OBS Networks ,’ Proc International Conf. on Transparent Optical Networks - ICTON, Athens, Greece, Vol. 3, pp. 138 - 141, June, 2008.

[C1]   M.C.R. Medeiros, R. Avó, P. Laurêncio, N.S. Correia, A. Barradas, H.J.A. da Silva, I. Darwazeh, J.E. Mitchell  and  P.M.N. Monteiro, ‘Radio over Fiber access network architecture emplying reflective semiconductor optical amplifiers,’ in Proc. International Conference on Transparent Optical Networks (ICTON)-Mediterranean Winter’07, paper Sa2.1,Tunisia December 2007. (Invited)

6.   Reports

[R3]   Analysis and Characterization of Reflective Semiconductors Optical Amplifiers, Report, Mark Guerreiro, 2009.

[R2]   Optical Transmitter for the RoFnet Project Demonstrator, Report by Paulo Almeida, Filipe Ferreira, Henrique Silva, June 2011.

[R1] Nonlinear Characteristics of RSOAs, Mark Guerreiro, 2011