Mac Protocols For Wireless Sensor Networks Over Radio-over-fiber Links

In this paper, two Medium Access Control (MAC) protocols exclusively tailored to WSNs over RoF (RWSNs) namely SPP-MAC (Scheduled Priority Polling Medium Access Control) (polling-based) and HMARS (Hybrid Medium Access Control for Hybrid Radio-over-Fiber Wireless Sensor Network Architecture) (hybrid-based) are proposed. They deal with the main problems in RWSNs i.e. the delay imposed by optical fiber and the existence of two collision domains: the wireless and the fiber optical links. The performance of these two protocols evince their effectiveness for the connection of WSNs by RoF links. © 2012 IEEE.254259Estrin, D., Govindan, R., Heidemann, J., Kumar, S., Next century challenges: Scalable coordination in sensor networks (1999) Proceedings of the 5th Annual ACM/IEEE International Conference on Mobile Computing and Networking, MobiCom '99, pp. 263-270. , (New York, NY, USA), ACMPottie, G.J., Kaiser, W.J., Wireless integrated network sensors (2000) Commun. ACM, 43, pp. 51-58. , MayFanimokun, A., Frolik, J., Effects of natural propagation environments on wireless sensor network coverage area (2003) Proceedings of the 35th Southeastern Symposium, pp. 16-20Hossen, M., Jang, B.-J., Kim, K.-D., Park, Y., Extension of wireless sensor network by employing rof-based 4g network (2009) Advanced Communication Technology, 2009. ICACT 2009. 11th International Conference on, 1, pp. 275-278. , febTang, J., Jin, X., Zhang, Y., Zhang, X., Cai, W., A hybrid radio over fiber wireless sensor network architecture (2007) Wireless Communications, Networking and Mobile Computing, 2007. WiCom 2007. International Conference on, pp. 2675-2678. , septFernando, X.N., Anpalagan, A., (2004) On the Design of Optical Fiber Based Wireless Access Systems, pp. 3550-3555Gerstel, O., Li, B., McGuire, A., Rouskas, G.N., Sivalingam, K., Zhang, Z., Special issue on protocols and architectures for next generation optical WDM networks (2000) IEEE Journal Selected Areas in Communications, , OctoberYe, W., Heidemann, J., Estrin, D., An energy-efficient MAC protocol for wireless sensor netwoks (2002) Annual Koint Conference of the Computer and Communicaton Societies (INFOCOM), 3, pp. 1567-1576. , (New York, NY, USA), NovemberVan Dam, T., Langendoen, K., An adaptive energy-efficient mac protocol for wireless sensor networks (2003) Proceedings of the 1st International Conference on Embedded Networked Sensor Systems, SenSys '03, pp. 171-180. , (New York, NY, USA), ACMLu, G., Krishnamachari, B., Raghavendra, C.S., An adaptive energy-efficient and low-latency MAC for data gathering in sensor networks (2004) WMAN, , (Santa Fe, NM, USA), AprilPolastre, J., Hill, J., Culler, D., Versatile low power media access for wireless sensor networks (2004) Proceedings of the 2nd International Conference on Embedded Networked Sensor Systems, SenSys '04, pp. 95-107. , (New York, NY, USA), ACMLin, P., Qiao, C., Wang, X., Medium access control with a dynamic duty cycle for sensor networks (2004) IEEE Wireless Communications and Networking Conference (WCNC), 3, pp. 1534-1536. , (Atlanta, GA, USA), MarchBurttner, M., Yee, E., Anderson, G.V., Han, R., X-MAC: A short preamble MAC protocol for duty-cycled wireless sensor networks (2006) 4th International Conference on Embedded Networked Sensor Systems (SenSys)(2006) 802.15.4-2006 IEEE Standard for Information TechnologyRoedig, U., Barroso, A., Sreenan, C.J., F-MAC: A deterministic media access control protocol without time syncronization (2006) European Conference on Wireless Sensor Networks (EWSN), pp. 276-291. , (Zurich, Switzerland), FebruarySchurgers, C., Tsiatsis, V., Ganeriwal, S., Srivastava, M., Optimizing sensor networks in the energy-latency-density design space (2002) IEEE Trans. Mobile Comput., pp. 70-80. , JanuaryGomes, P., Da Fonseca, N., Branquinho, O., Analysis of performance degradation in Radio-over-Fiber systems based on IEEE 802.16 protocol (2009) LATINCOM '09. IEEE Latin-American Conference on Communications 2009, pp. 1-6. , septDas, A., Mamd, M., Nkansah, A., Gomes, N.J., Effects on IEEE 802.11 MAC throughput in wireless LAN over fiber systems (2007) Journal of Lightwave Technology, 25, pp. 3321-3328. , Novembe

Broadband Linearization Technologies for Broadband Radio-over-Fiber Transmission Systems

Wireless access networks consist of three sections, i.e., back-haul, front-haul, and wireless transmission, where the front-haul transmission systems are to distribute radio frequency (RF) signals to antenna towers. For current low-capacity wireless access, RF signals over coaxial cables, digital fiber-optic transmission, microwave point-to-point transmission, and narrowband radio-over-fiber (RoF) transmission have been used for the front-haul transmission systems. However, with the increase of demand of high capacity wireless access and also use of massive multiple-input and multiple-output (MIMO) antennas, low-cost, simple and broadband front-haul transmission systems are required in current 4G and in particular the future 5G wireless. RoF transmission system, which is based on optical subcarrier modulation, combines the advantages of both optical fiber and radio transmission, where the optical fiber has low loss, low cost, extremely high capacity, lightweight, and immunity to electromagnetic interference, and the radio transmission simplifies remote radio units (RRUs) at antenna towers. Furthermore, radio transmission based front-haul is transparent to RF signal frequency and wireless protocol, i.e., upgradable, in addition to simplified RRUs. Unfortunately, RoF is an analog optical transmission, and it is well known that any analog transmission is susceptible to nonlinear distortion. To be more specific, nonlinear distortion is the major limit for RoF transmission. In fact, all inline functional optical and electrical components used in RoF transmission systems may induce the nonlinear distortion. Specifically in RoF based front-haul systems, two key functions, i.e., RF power amplification and optical subcarrier modulation, are the main factors in introducing nonlinear distortions. The nonlinear distortions from RF power amplifiers (PAs) have been studied for decades. Therefore, the nonlinear distortions from the optical subcarrier modulation are the main concern in this thesis. The nonlinear distortions include harmonic distortions (HDs) and intermodulation distortions (IMDs). For narrow band RF signals, the HDs can be suppressed by RF filtering, but it may be impossible for the IMDs to be filtered out. For broadband RF signals, both HDs and IMDs could fall in the passband of RF signals and introduce crosstalk, and therefore both of them are required to be suppressed, i.e., linearization required. In the past decades, linearization for RF PAs has been investigated extensively, mainly focusing on signal processing based linearization, i.e., digital linearization. Unfortunately, the digital linearization is typically limited to the RF signals with up to 20 MHz bandwidth. Based on the current technologies of signal processing hardware, linearization for 1 GHz RF signals can be done, but the complexity and cost are beyond the practical applications. In order to explore broadband RoF transmission systems that support broadband front-haul, simple, low cost, and broadband linearization is pivotal. In this thesis, two linearization technologies for RoF transmission systems are investigated comprehensively, i.e., analog predistortion circuit (PDC) and dual wavelength optical linearization. Two novel PDCs are designed and investigated to suppress 3rd order IMD (IMD3) of RoF transmission systems. The PDCs have the advantages of broad bandwidth, compact size, and low cost. The first PDC is designed to have a bandwidth from 7 to 18 GHz, using two zero-bias Gallium Arsenide (GaAs) Schottky diodes as predistorter. The linearization using this PDC is verified in externally modulated RoF transmission systems. When a Mach-Zehnder modulator (MZM) is used for the optical subcarrier modulation, the input power at 1 dB compression point (P1dB) of the RoF transmission system is improved by 0.4 and up to 2.2 dB from 7 to 18 GHz. The spurious-free dynamic range (SFDR) is improved by more than ~10 dB from 7 to 14 GHz and ~6 dB from 15 to 18 GHz. When an electro-absorption modulator (EAM) is used, the input P1dB is improved by 0.8 and up to 3.8 dB from 8 to 17 GHz. The SFDR is improved by more than ~9 dB from 7 to 14 GHz and ~4 dB from 15 to 18 GHz. The second PDC is designed to have an ultra broad bandwidth from 10 MHz to 30 GHz, using a dual Schottky diode as the predistorter. The linearization using this PDC is investigated in both directly and externally modulated RoF transmission systems. The SFDR at 8 GHz is improved by 11.9 dB for a directly modulated RoF transmission. The SFDR is improved by more than 10 dB from 1 to 5 GHz and more than 5 dB from 1 to 30 GHz for an externally EAM modulated RoF transmission. Similarly, the SFDR is improved by more than 12 dB from 2 to 5 GHz and more than 5 dB from 2 to 30 GHz for an externally MZM modulated RoF transmission. When WiFi signals are transmitted over the externally modulated RoF systems for back-to-back (BTB) and 20 km single mode fiber (SMF), the error vector magnitudes (EVMs) are improved by 0.4 and up to 5.1 dB by using the PDC. Dual wavelength linearization (DWL) technique is investigated compressively to suppress 2nd and 3rd order nonlinearities of externally modulated RoF transmission systems simultaneously, including HDs and IMDs. The linearization is verified in both EAM and MZM modulated RoF transmission systems. Theoretical analysis is given for the first time to understand DWL technique. The experimental results agree with the theoretical analyses. In the externally EAM modulated RoF transmission systems, when the 2nd order nonlinearity is maximally suppressed, 11.5 and 1.8 dB improvements of the SFDRs with respect to HD2 and HD3 respectively are achieved by using DWL simultaneously. 8.5 and 1.3 dB improvements of the SFDRs with respect to IMD2 and IMD3 respectively are also achieved. Correspondingly, 3 and 4 dB improvements of the input and output P1dBs respectively are obtained. When the 3rd order nonlinearity is maximally suppressed, the SFDRs with respect to HD3 and IMD3 are improved by 8.1 and 20.4 dB, respectively, and corresponding 7.7 and 11.7 dB improvements of the input and output P1dBs respectively are achieved. Furthermore, IMD5 is also suppressed, and the SFDR5 with respect to IMD5 is improved by 7.1 dB. Moreover, the RoF transmission of WiFi signals at 2.4 and 5 GHz are also linearized by using DWL technique. 3.5 dB at 2.4 GHz and 2.8 dB at 5 GHz improvements of the EVMs are obtained. For an externally MZM modulated RoF transmission system, DWL is also investigated theoretically and experimentally. In the system, it is found that the SFDRs with respect to HD2 and HD3 are both improved at the same time when the even order nonlinearities are suppressed, in which the power of the RF signal and 3rd order nonlinearity is increased by the same level. Thus, the SFDR3 is still improved even the 3rd order nonlinearity is increased. Compared to using a single 1553 nm laser, the SFDRs with respect to HD2 and HD3 are improved by 38.4 and 12.1 dB

Medium-transparent MAC protocols for converged optical wireless networks

In order to address the explosive demand for high-capacity and omnipresent wireless access, modern cell-based wireless networks are slowly adopting two major solution roadmaps. The first is the employment of small-cell formations in order to increase the overall spectral efficiency, whereas the second is the employment of higher frequency bands, such as the mm-wave 60GHz band, that offers vast amounts of bandwidth. Depending on the specific application, the above solutions inevitably require the installation and operational management of large amounts of Base Stations (BSs) or Access Points (APs), which ultimately diminishes the overall cost-effectiveness of the architecture. In order to reduce the system cost, Radio over Fiber (RoF) technology has been put forward as an ideal candidate solution, due to the fact that it provides functionally simple antenna units, often termed as Remote Antenna Units (RAUs) that are interconnected to a central managing entity, termed as the Central Office (CO), via an optical fiber. Although extensive research efforts have been dedicated to the development of the physical layer aspects regarding RoF technologies, such as CO/RAU physical layer design and radio signal transport techniques over fiber, very limited efforts have con-centrated on upper layer and resource management issues. In this dissertation, we are concerned with access control and resource management of RoF-based mm-wave network architectures targeting the exploitation of the dual medium and its centralized control properties in order to perform optimal optical/wireless/time resource allocation. In this dissertation, we propose a Medium-Transparent MAC (MT-MAC) protocol that concurrently administers the optical and wireless resources of a 60GHz RoF based network, seamlessly connecting the CO to the wireless terminals through minimal RAU intervention. In this way, the MT-MAC protocol forms extended reach 60GHz WLAN networks offering connectivity amongst wireless devices that are attached to the same or different RAUs under both Line of Sight (LOS) and non LOS conditions. The notion of medium-transparency relies on two parallel contention periods, the first in the optical domain and the second in the wireless frequency and time domains, with nested dataframe structures. The MT-MAC operation is based on a proposed RAU design that allows for wavelength selectivity functions, thus being compatible with completely passive optical distribution network implementations that are predominately used by telecom operators today. Two variants of the MT-MAC protocol are considered. The first offers dynamic wavelength allocation with fixed time windows, whereas the second targets fairness-sensitive applications by offering dynamic wavelength allocation with dynamic transmission opportunity window sizes, based on the number of active clients connected at each RAU. Both variants of the protocol are evaluated by both simulation and analytical means. For the latter part, this thesis introduces two analytical models for calculating saturation throughput and non-saturation packet delay for the converged MT-MAC protocol. Finally, this thesis presents an extensive study regarding the network planning and formation of 60GHz Gigabit WLAN networks when the latter are deployed over existing Passive Optical Network (PON) infrastructures. Three possible architectures where studied: i) the RoF approach, ii) the Radio & Fiber approach and iii) the hybrid RoF-plus-R&F approach that combines the properties of both the aforementioned architectures. During the elaboration of this thesis, one major key conclusion has been extracted. The work proposed in this thesis considers that there is a fundamental requirement for implementing new converged optical/wireless MAC protocols, that have the complete overview of both available resources in order to effectively administer the hybrid Radio-over-Fiber networks.A fin de atender la demanda explosiva de alta capacidad y acceso inalámbrico omnipresente, las redes inalámbricas basadas en celdas están poco a poco adoptando dos principales guías de solución. La primera es el empleo de formaciones de celdas pequeñas con el fin de aumentar la eficiencia espectral global, mientras que la segunda es el empleo de bandas de frecuencia superior, como la banda de 60GHz, la cual ofrece una gran cantidad de ancho de banda. Dependiendo de la aplicación en específico, las soluciones anteriores inevitable-mente requieren de una instalación y una gestión operativa de grandes cantidades de Estaciones Base o Puntos de Acceso, que en última instancia disminuye la rentabilidad de la arquitectura. Para reducir el coste, la tecnología radioeléctrica por fibra (RoF) se presenta como una solución ideal debido al hecho de que proporciona unidades de antenas de sim-ple funcionamiento, a menudo denominadas Unidades de Antenas Remotas (RAUs), las cuales están interconectadas a una entidad central de gestión, denominada Oficina Central (CO), a través de la fibra óptica. A pesar de que se han dedicado muchos esfuerzos de investigación al desarrollo de varios aspectos de las capas física con respecto a las tecnologías RoF, muy pocos esfuerzos se han concentrado en la capa superior y cuestiones de gestión de recursos. En esta tesis, nos enfocando en el control de acceso y gestión de recursos de arquitecturas RoF y comunicaciones milimétricas, con el fin de aprovechar y explotar el medio dual y las propiedades para realizar una óptima asignación de los recursos ópticos, inalámbricos y temporales. Nosotros proponemos un protocolo Transparente al Medio MAC (MT-MAC) que simultáneamente administre los recursos ópticos e inalámbricos de una red RoF a 60GHz, conectando a la perfección el CO a los terminales inalámbricos a través de una mínima intervención RAU. El protocolo MT-MAC forma unas redes WLAN 60GHz de alcance extendido, ofreciendo así conectividad entre los dispositivos inalámbricos que están conectados al mismo o diferentes RAUs bajo con o sin Línea de Vista (condiciones LOS o NLOS) respectivamente. La noción de transparencia al medio se basa en dos períodos de contención para-lelos, el primero en el dominio óptico y el segundo en la frecuencia inalámbrica y dominio del tiempo, con estructuras de datos anidados. La operación MT-MAC se basa en proponer un diseño RAU que permita la selectividad de funciones de longitud de onda. Dos variantes del protocolo MT- MAC son considerados; el primer ofrece asignación de longitud de onda dinámica con ventanas de tiempo fijo, mientras que la segunda tiene como objetivo entornos de aplicaciones sensibles ofreciendo asignación de longitud de onda con tamaño de ventana de oportunidad de transmisión dinámico, basado en el número de clientes conectados en cada RAU. Ambas variantes del protocolo están evaluadas tanto por medios analíticos como de simulación. En la segunda parte, esta tesis introduce dos modelos analíticos para calcular el rendimiento de saturación y no saturación del retardo de paquetes para el protocolo MT-MAC convergente. Finalmente, esta tesis presenta un extenso estudio de la planificación de red y la formación de redes 60GHz Gigabit WLAN cuando esta se encuentra desplegada sobre las ya existente infraestructuras de Redes Ópticas Pasivas (PONs). Tres posibles arquitecturas han sido estudiadas: i) el enfoque RoF, ii) el enfoque Radio y Fibra , y iii) el enfoque híbrido, RoF más R&F el cual combina las propiedades de ambas arquitecturas anteriormente mencionadas. Durante la elaboración de esta tesis, se ha extraído una importante conclusión: hay un requerimiento fundamental para implementar nuevos protocolos ópticos/inalámbricos convergentes, que tengan una completa visión de ambos recursos disponibles para poder administrar efectivamente las redes de tecnología RoF.Postprint (published version