Showing papers in "Journal of Optical Networking in 2009"
TL;DR: In this paper, a review of the work carried out within the EU Network of Excellence ISIS on radio-over-fiber systems for the support of current and emerging wireless networks is reviewed.
Abstract: Some of the work carried out within the EU Network of Excellence ISIS on radio-over-fiber systems for the support of current and emerging wireless networks is reviewed. Direct laser modulation and externally modulated links have been investigated, and demonstrations of single-mode fiber and multimode fiber systems are presented. The wireless networks studied range from personal area networks (such as ZigBee and ultrawideband) through wireless local area networks to wireless metropolitan area networks (WiMAX) and third-generation mobile communications systems. The performance of the radio-over-fiber transmission is referenced to the specifications of the relevant standard, protocol operation is verified, and complete network demonstrations are implemented.
269 citations
TL;DR: In this paper, the work carried out within the European integrated project Integrated Photonic mm-wave Functions for Broadband Connectivity (IPHOBAC) on the development of photonic components and radio-over-fiber technologies for broadband wireless communication is reviewed.
Abstract: Some of the work carried out within the European integrated project Integrated Photonic mm-Wave Functions for Broadband Connectivity (IPHOBAC) on the development of photonic components and radio-over-fiber technologies for broadband wireless communication is reviewed. In detail, 60 GHz outdoor radio systems for >10 Gbits/s and 60 GHz indoor wireless systems offering >1 Gbit/s wireless transmission speeds are reported. The wireless transmission of uncompressed high-definition TV signals using the 60 GHz band is also demonstrated.
104 citations
TL;DR: This paper presents an overview of the different techniques and schemes to overcome some of the impairments for transporting mm-wave signals over optical fibers.
Abstract: Hybrid fiber-wireless networks for fixed wireless access operating in the millimeter-wave (mm-wave) frequency region have been actively pursued to provide ultrahigh bandwidth for untethered connectivity. Moving the radio operating frequency into the mm-wave region overcomes the spectral congestion in the lower microwave region and is also capable of providing high-capacity broadband wireless services in a picocellular or microcellular architecture. Optical fiber backhaul provides the broadband interconnectivity between a centralized location and a large number of high-throughput antenna base stations necessary in such an architecture. The transportation of mm-wave wireless signals within the hybrid network is subject to numerous impairments ranging from low conversion efficiency to fiber chromatic dispersion and also to signal degradation due to nonlinearity along the link. One of the major technical challenges in implementing these networks lies in the mitigation of these impairments that the wireless signals experience while traversing the links. In this paper, we present an overview of the different techniques and schemes to overcome some of the impairments for transporting mm-wave signals over optical fibers.
44 citations
TL;DR: In this article, a scalable photonic interconnection network architecture is proposed whereby a Clos network is populated with broadcast-and-select stages, where a low distortion space switch technology based on recently demonstrated quantum-dot semiconductor optical amplifier technology is used as the base switch element.
Abstract: A scalable photonic interconnection network architecture is proposed whereby a Clos network is populated with broadcast-and-select stages. This enables the efficient exploitation of an emerging class of photonic integrated switch fabric. A low distortion space switch technology based on recently demonstrated quantum-dot semiconductor optical amplifier technology, which can be operated uncooled, is used as the base switch element. The viability of these switches in cascaded networks is reviewed, and predictions are made through detailed physical layer simulation to explore the potential for larger-scale network connectivity. Optical signal degradation is estimated as a function of data capacity and network size. Power efficiency and physical layer complexity are addressed for high end-to-end bandwidth, nanosecond-reconfigurable switch fabrics, to highlight the potential for scaling to several tens of connections. The proposed architecture is envisaged to facilitate high-capacity, low-latency switching suited to computing systems, backplanes, and data networks. Broadband operation through wavelength division multiplexing is studied to identify practical interconnection networks scalable to 100 Gbits/s per path and a power consumption of the order of 20 mW/(Gbits/s) for a 64×64 size interconnection network.
42 citations
TL;DR: In this paper, a cost-effective frequency-quadrupling technique capable of generating millimeter-wave signals up to 72 GHz was proposed, with an optical carrier and harmonic distortion suppression ratio exceeding 36 dB.
Abstract: This study discusses two key technologies used in radio-over-fiber (RoF) systems, namely, the generation and transmission of millimeter-wave signals and optical modulation schemes capable of carrying vector signal formats and utilizing the continuous performance improvements offered by digital signal processing. A cost-effective frequency-quadrupling technique capable of generating millimeter-wave signals up to 72 GHz is proposed. The generated optical millimeter-wave signals have very high quality, with an optical carrier and harmonic distortion suppression ratio exceeding 36 dB. An optical modulation scheme that can support a 64-QAM, 16 Gbits/s orthogonal frequency-division multiplexing RoF system is also demonstrated. Results of this study demonstrate that both methods offer realistic solutions to support future wireless systems.
29 citations
TL;DR: In this paper, the authors describe recent research activities and results in the area of photonic switching carried out within the framework of the EU-funded e-Photon/ONe+ network of excellence, Virtual Department on Optical Switching.
Abstract: This paper describes recent research activities and results in the area of photonic switching carried out within the framework of the EU-funded e-Photon/ONe+ network of excellence, Virtual Department on Optical Switching. Technology aspects of photonics in switching and, in particular, recent advances in wavelength conversion, ring resonators, and packet switching and processing subsystems are presented as the building blocks for the implementation of a high-performance router for the next-generation Internet.
27 citations
TL;DR: This work identifies the factors that result in packet delay reduction with excess bandwidth distribution compared to IPACT-limited and discovers that existing offline excess distribution mechanisms become unstable at moderate to high loads in long-range EPONs with large round-trip propagation delays.
Abstract: Excess bandwidth distribution techniques have recently been proposed to improve the dynamic bandwidth allocation in Ethernet passive optical networks (EPONs). We compare existing offline excess bandwidth distribution with conventional limited interleaved polling with adaptive cycle time (IPACT-limited) in terms of packet delay performance. We identify the factors that result in packet delay reduction with excess bandwidth distribution compared to IPACT-limited and discover that existing offline excess distribution mechanisms become unstable at moderate to high loads in long-range EPONs with large round-trip propagation delays. We propose a novel online excess bandwidth distribution (OEBD) mechanism to provide stable excess bandwidth distribution even at high loads in long-range EPONs. We demonstrate how OEBD can be tuned via parameters to provide grant sizing between limited and gated service.
24 citations
TL;DR: In this paper, the authors present a theoretical treatment that analyzes the amplified system operational requirements and justifies this analysis through the experiment, considering the dc offset that is introduced into the receiver as a result of the significant amplified spontaneous emission powers present in amplified PONs.
Abstract: Passive optical networks (PONs) are being aggressively pursued as a means of delivering access network solutions. The cost benefits resulting from a reduction in the number of interfaces between nodes has enabled increasing deployment of a PON delivering fiber to the home and fiber to the curb. However, in many cases, the need for high split ratios or an extended-reach requires amplification to overcome additional losses. Erbium-doped amplifiers have a limited use in PONs since the operational wavelengths typically include backhaul at 1.3 mu m. Semiconductor optical amplifiers (SOAs) offer a cost-effective solution with a migration path toward integration; deployment options include its use as a preamplifier, booster, or midspan amplifier. We present a theoretical treatment that analyzes the amplified system operational requirements and justifies this analysis through the experiment. The analysis considers for the first time to our knowledge the dc offset that is introduced into the receiver as a result of the significant amplified spontaneous emission powers present in amplified PONs, where filter widths are typically 20 nm or greater.
22 citations
TL;DR: In this paper, an integer linear programming (ILP) network design model was proposed to provide specified dual-failure restorability levels, and a new model was developed that allows for an enhanced dual failure restoreability approach.
Abstract: Following the approach of a prior integer linear programming network design model to provide specified dual-failure restorability levels, we develop a new model that allows for an enhanced dual-failure restorability approach. We observe that some dual-failure scenarios affecting a single p-cycle can, in fact, be partially restorable, contravening the typical understanding of p-cycle network restorability. We show that a p-cycle network that utilizes this enhanced dual-failure restorability can be designed more cost-effectively than one without it, saving as much as 20.01% in capacity design costs and averaging 7.93% over the test cases we studied.
14 citations
TL;DR: In this article, the authors proposed an optical double-sideband with suppressed carrier signal for delivering microwave and millimeter-wave signals containing broadband multimedia services over fiber-optic networks.
Abstract: Radio over fiber is a very attractive technology for delivering microwave and millimeter-wave signals containing broadband multimedia services. The generation of an optical double-sideband with suppressed carrier signal is a straightforward method because only one microwave modulator driven at half the millimeter-wave frequency is required. Then only one sideband is modulated with 10 Gbits/s baseband data forming a millimeter-wave single-sideband signal. Transmission experiments prove this modulation scheme to be dispersion tolerant, and error-free transmission is demonstrated after 21 km of single-mode fiber and wireless links up to 2.5 m.
14 citations
TL;DR: This paper presents what is believed to be a novel double-spreading mechanism, both in the wireless and optical domains for the cascaded RoF systems, which would be an ideal solution for WCDMA-based wireless systems and the upcoming 4G with backbone cascading RoF networks.
Abstract: The main challenge for present and future personal communication systems and personal communication networks stems from the exponentially growing user demand. Radio over fiber (RoF), the combination of optical and wireless technologies, has many advantages and a wide range of applications. The 3G wireless communication technology uses wideband code division multiple access (WCDMA) standards to support the broadband services, and RoF technology will be an appropriate candidate in such environments. This paper presents what is believed to be a novel double-spreading mechanism, both in the wireless and optical domains for the cascaded RoF systems. Although a star configuration is the most popular because of its easy maintenance, the cascade or bus configuration can reduce the fiber counts and is hence cost-effective. Simulation studies on bit-error-rate performance for different numbers of users using orthogonal variable spread factor (OVSF) codes in the wireless domain and Walsh-Hadamard codes for optical code division multiple access (OCDMA) in the optical domain have been carried out. Hence, in view of less system complexity and cost, the proposed double-spreading technique would be an ideal solution for WCDMA-based wireless systems and the upcoming 4G with backbone cascaded RoF networks.
TL;DR: In this article, the interoperability of standard WiMAX and gigabit passive optical networks (GPONs) is shown to overcome the wireless spectrum congestion and provide resilience for GPON through the use of overlapping radio cells, where the application of centralized control in the optical line terminal and time division multiplexing for upstream transmission enables efficient dynamic bandwidth allocation for wireless users on a single wavelength as well as minimized optical beat interference at the optical receiver.
Abstract: The interoperability of standard WiMAX and gigabit passive optical networks (GPONs) is shown to overcome the wireless spectrum congestion and provide resilience for GPON through the use of overlapping radio cells. The application of centralized control in the optical line terminal and time division multiplexing for upstream transmission enables efficient dynamic bandwidth allocation for wireless users on a single wavelength as well as minimized optical beat interference at the optical receiver. The viability of bidirectional transmission of multiple uncoded IEEE 802.16d channels by means of a single radio-frequency subcarrier at transmission rates of 50 and 15 Mbits/s downstream and upstream, respectively, for distances of up to 21 km of integrated GPON and WiMAX microcell links is demonstrated.
TL;DR: Simulation results show that the proposed algorithm does not breach bandwidth and delay bounds for guaranteed service traffic even under the highest loads, and analyze the lower bound for providing delay guarantees.
Abstract: This paper addresses the problem of providing bandwidth and delay guarantees in passive optical networks. To resolve this problem we propose an algorithm that provides absolute bandwidth and delay bound guarantees. Simulation results show that the proposed algorithm does not breach bandwidth and delay bounds for guaranteed service traffic even under the highest loads. Additionally, we analyze the lower bound for providing delay guarantees.
TL;DR: A novel hierarchical integrated scheduling algorithm is proposed that significantly improves the throughput-delay performance and triple-play quality-of-service support for fixed and mobile users and clearly outperforms the widely deployed weighted fair queuing scheduler.
Abstract: This paper introduces a novel fiber-wireless (FiWi) network architecture, called SuperMAN, and investigates the optical-wireless integration of a resilient packet ring (RPR) and WiMAX networks. We propose a novel hierarchical integrated scheduling algorithm that significantly improves the throughput-delay performance and triple-play quality-of-service support for fixed and mobile users. By means of extensive simulations we show in a benchmark comparison that the proposed hierarchical scheduler clearly outperforms the widely deployed weighted fair queuing (WFQ) scheduler in terms of mean aggregate throughput and mean delay as well as robustness for voice, video, and data traffic under realistic wireless channel conditions.
TL;DR: A modified theoretical model for TCP Reno over OBS is investigated, which is more accurate in modeling TCP Reno throughput compared with previous works and can further verify the experimental results.
Abstract: It is well known that the classic transmission control protocol (TCP) Reno is inadequate to address the requirements of emerging grid applications on an optical burst switching (OBS) network. To find the most efficient TCP in the scenario of grid over OBS, in this paper, the implementation of a traffic-driven labeled OBS (LOBS) network test bed is presented and the performance of several prominent high-speed TCPs, including HSTCP, TCP Westwood, and FAST TCP, are experimentally compared over the test bed. A modified theoretical model for TCP Reno over OBS is investigated, which is more accurate in modeling TCP Reno throughput compared with previous works and can further verify the experimental results.
TL;DR: The spatial and temporal traffic demand is analyzed and modeled through simulation, as a means of selecting the optimum location for the base stations/antenna units (BSs/AUs) in the network.
Abstract: The development of airports such as the recently inaugurated Heathrow Terminal 5, as well as the increasing number of people using these facilities every day for business reasons or just for pleasure, reveals the importance of adequate and reliable communication facilities in this context. This environment is characterized by multiservice, multistandard wireless technologies and a highly variable traffic demand in space and time due to passenger flow, behavior, and usage from the terminal's entrance to the corresponding boarding gate, ruled by flight departure schedules, in the indoor environment. The Intelligent Airport (TINA) project establishes its objective as the creation of a seamless hybrid wireless and wired infrastructure capable of providing users with a wide range of services, based on radio-over-fiber (RoF) networks, anticipating the deployment of multiple air interfaces within 4G networks. In this paper the spatial and temporal traffic demand is analyzed and modeled through simulation, as a means of selecting the optimum location for the base stations/antenna units (BSs/AUs) in the network. A load-balancing technique is applied to ease the load on congested cells using strategically located fixed relay nodes, and the network's behavior is analyzed for different BS properties.
TL;DR: A fuzzy-logic-based scheduling algorithm that considers four different metrics to allocate an upstream bandwidth to optical network units (ONUs) that would reduce the average level of power fluctuations in a PON system and will also provide high-level service differentiation between packets of different importance.
Abstract: Presented is a fuzzy-logic-based scheduling algorithm for passive optical networks (PONs) that considers four different metrics to allocate an upstream bandwidth to optical network units (ONUs). The metrics considered are the delay of the head-of-the-line packets at the ONUs, the importance level of the packets, the relative ONU's buffer fullness, and the level of the power fluctuation from one ONU to another. One of the advantages of a fuzzy controller is the fact that, regardless of the design complexity, the controller can be implemented as a simple look-up table, which makes it ideal for high-speed operation. Further facilitation of implementation was achieved by realization of the fuzzy algorithm through a two-stage hierarchal architecture. Moreover, linear predictive filters have been used to predict the traffic arrival rate and the packet delay at the ONUs. Compared with the round-robin scheduling algorithm, the results show significant performance improvement in terms of the overall packets delay as well as jitter when the proposed algorithm in employed. Furthermore, using this algorithm would reduce the average level of power fluctuations in a PON system and will also provide high-level service differentiation between packets of different importance.
TL;DR: The results indicate that RDM is indeed the best of simple, single-stage CAMs available, thus confirming the choice of both the P802.3ah Task Force and Full Service Access Network (FSAN)/ITU-T at the time when their respective 1G-EPON and GPON specifications were written.
Abstract: Operation of all time division multiple access passive optical networks (PONs), regardless of the layer 2 protocol in use, requires the utilization of the so-called discovery process allowing for identification and registration of newly activated optical network units (ONUs). For the duration of the discovery process, all transmissions from already registered ONUs are halted, decreasing the available upstream bandwidth. The number of discovery windows required to successfully register all contending ONUs depends on the collision probability for their registration requests. To decrease such a collision probability for registration requests, several types of collision avoidance mechanisms (CAMs) can be used in various flavors of passive optical network (xPON), as we examine in more detail. A random delay mechanism (RDM) is typically exploited in 1 Gbit/s Ethernet PON (1G-EPON) and gigabit PON (GPON), though other CAMs are also available. It is our goal therefore to examine the efficiency of all known CAMs, compare them in quantitative and qualitative manner, and recommend the best mechanism for the next generation of xPON systems, minimizing the average number of discovery cycles required to register contending ONUs (maximizing thus the registration success probability). The results indicate that RDM is indeed the best of simple, single-stage CAMs available, thus confirming the choice of both the P802.3ah Task Force (TF) and Full Service Access Network (FSAN)/ITU-T at the time when their respective 1G-EPON and GPON specifications were written.
TL;DR: It is demonstrated that the switching time of the currently available WSS prevents the protection of the complete set of affected label-switched paths (LSPs) within 50 ms after fault detection, and two alternative strategies can be considered.
Abstract: We implement shared-path protection (SPP) with extra traffic in automatically switched optical network (ASON) rings provided with a generalized multiprotocol label switching (GMPLS) control plane. The protection time provided by the SPP scheme is analyzed as a function of the switching time of the wavelength-selective switches (WSS), the key components to building reconfigurable optical nodes. We demonstrate that the switching time of the currently available WSS prevents the protection of the complete set of affected label-switched paths (LSPs) within 50 ms after fault detection. Therefore, two alternative strategies can be considered, namely, (1) the definition of two classes of protection with different requirements in terms of protection time, and (2) a real-time mechanism to decide, on the basis of the current number of LSPs to protect, whether the protection scheme to apply is either at the path layer or at the link layer. When protecting at the path layer, part of the extra traffic will be saved, whereas all the extra traffic will be preempted when protecting at the link layer.
TL;DR: In this paper, a novel system for the distribution of high-definition video streams in a residential environment is demonstrated, which utilizes impulse radio ultrawideband (IR-UWB) technology integrated with a fiber-based distribution network.
Abstract: What we believe to be a novel system for the distribution of high-definition video streams in a residential environment is demonstrated. The system utilizes impulse radio ultrawideband (IR-UWB) technology integrated with a fiber-based distribution network. The pulses are directly generated in the optical domain, and the receiver is implemented with a carrier recovery system for the demodulation. The system was built and tested to demonstrate error-free operation of the distribution network and the receiver. Spectrum shaping by varying the pulse position within the bit slot to optimize system performance is also examined.
TL;DR: In this paper, a WDM-PON architecture compatible with radio-over-fiber (ROF) systems is proposed to provide both wired and wireless services, using a frequency-quadrupled modulation scheme.
Abstract: We demonstrate what we believe to be a novel WDM-PON architecture compatible with radio-over-fiber systems to provide both wired and wireless services. A frequency-quadrupled modulation scheme is employed to generate optical millimeter waves and realize centralized lightwaves in radio-over-fiber systems.
TL;DR: In this article, a proportional, integral, derivative (PID) controller is implemented in each edge node, and the edge node determines the amount of data to be transmitted with PID control so that a constant amount can be stored in the buffer.
Abstract: We propose a dynamic light-path establishment method for using wavelengths effectively. In our proposed method, a proportional, integral, derivative (PID) controller is implemented in each edge node. The edge node determines the amount of data to be transmitted with PID control so that a constant amount of data can be stored in the buffer. In addition, light paths are established and released dynamically by comparing the output signal of the PID controller with the maximum amount of data that can be transmitted with the established light paths. Because data can be stored in the buffer for a short time, it is expected that the number of established light paths decreases. We evaluate the performance of the proposed method and investigate the impact of the setting parameters. The effectiveness of the proposed method is shown through a comparison with the conventional method.
TL;DR: In this article, a wide overview of the progress on certain key areas in the field of radio-over-optical-fiber network technologies, including the enabling technologies, architectures, and systems design, is presented.
Abstract: This feature issue of the Journal of Optical Networking gives a wide overview of the progress on certain key areas in the field of radio-over-optical-fiber network technologies, including the enabling technologies, architectures, and systems design.
TL;DR: This work presents what it believes to be a new approach to optical networking based on a paradigm of coarse optical circuit switching by default and adaptive rerouting over circuits with spare capacity, and demonstrates that the adaptive load-balancing approach is robust to sudden unexpected traffic changes.
Abstract: As Internet traffic continues to grow unabated at an exponential rate, it is unclear whether the existing packet-routing network architecture based on electronic routers will continue to scale at the necessary pace. On the other hand, optical fiber and switching elements have demonstrated an abundance of capacity that appears to be unmatched by electronic routers. In particular, the simplicity of circuit switching makes it well suited for optical implementations. We present what we believe to be a new approach to optical networking based on a paradigm of coarse optical circuit switching by default and adaptive rerouting over circuits with spare capacity. We consider the provisioning of long-duration quasi-static optical circuits between edge routers at the boundary of the network to carry the traffic by default. When the provisioned circuit is inadequate, excess traffic demand is rerouted through circuits with spare capacity. In particular, by adaptively load balancing across circuits with spare capacity, excess traffic is routed to its final destination without the need to create circuits on the fly. Our evaluations on two separate real, large Internet service provider point-of-presence-level topologies, Abilene and GEANT, show that only a very small amount of excess traffic needs to be rerouted even during peak traffic hours when the circuit configurations are carefully chosen and that this excess traffic could always be accommodated using our adaptive rerouting approach. We also demonstrate that our adaptive load-balancing approach is robust to sudden unexpected traffic changes by demonstrating its ability to reroute traffic under a number of hot-spot scenarios.
TL;DR: In this article, a simple Fabry-Perot (FP) etalon was used as the spectral reshaper for WDM access networks, and the effects of the original extinction ratio and the adiabatic chirp on the spectral re-shaping were investigated.
Abstract: Spectral and waveform reshaping schemes can enhance the transmission distance of fiber links that use directly modulated lasers as transmitters. We prove the feasibility of using a simple Fabry-Perot (FP) etalon as the spectral reshaper for applications in wavelength division multiplexing (WDM) access networks. The transient chirp and adiabatic chirp of a directly modulated laser are analyzed in detail by using the time-resolved chirp measurement. The effects of the original extinction ratio and the adiabatic chirp on the spectral reshaping are clarified to obtain the optimal operation conditions. It is shown that placing a single-cavity FP etalon filter after multiple 10 Gbits/s directly modulated lasers can extend their transmission distances from 50 km in the 1.55 μm wavelength window. Due to the limited filtering capability of the etalon, the choice of the original extinction ratio and finesse of the etalon is discussed in detail from the experiments and simulation.
TL;DR: In this paper, the authors experimentally demonstrate several key technologies to further explore the converged benefits of optical and wireless systems to offer wireless high-definition (HD) services for both fixed and mobile users.
Abstract: We experimentally demonstrate several key technologies to further explore the converged benefits of optical and wireless systems to offer wireless high-definition (HD) services for both fixed and mobile users. These technologies include spectrum-efficient multiband generation and dispersion-tolerant transmission, long-reach transmission without dispersion compensation, and a transport feasibility study for flexible optical routing using multiple reconfigurable optical add-drop multiplexers (ROADMs). Using the developed system, we successfully implement the testbed trial on the delivery of uncompressed 270 Mbits/s standard-definition television and 1.485 Gbits/s HD television video signals over optical fiber and air links.
TL;DR: Simulation results confirm the expectation that VLB-HCSP can achieve a desirable compromise between cost and failure recovery time compared with the previous V LB-based method, while HCMLN performs even more inspiringly for being able to provide both a low-cost budget and a fast recovery at the same time.
Abstract: This paper investigates the issue of survivable routing to prevent arbitrary single-link failures in WDM networks when the traffic information is partially known. Two novel protection schemes called valiant-load-balancing- (VLB-) based hop constraint segment protection (VLB-HCSP) and hop constraint minimizing leaf nodes (HCMLN) are proposed and evaluated. Simulation results confirm our expectation that VLB-HCSP can achieve a desirable compromise between cost and failure recovery time compared with the previous VLB-based method, while HCMLN performs even more inspiringly for being able to provide both a low-cost budget and a fast recovery at the same time, in contrast to VLB-HCSP and the other existing schemes.
TL;DR: Hybrid multiplexing and demultiplexing schemes with the capability to integrate microwave and millimeter-wave frequency radio-over-fiber signals in a wavelength division multiplexed passive optical network (WDM-PON) infrastructure are proposed in this article.
Abstract: Hybrid multiplexing and demultiplexing schemes with the capability to integrate microwave and millimeter-wave frequency radio-over-fiber signals in a wavelength division multiplexed passive optical network (WDM-PON) infrastructure are proposed. The proposed schemes exploit the benefits of a spectrally efficient wavelength-interleaving technique and enhance the performance of optical millimeter-wave signals without employing an additional device. The schemes are demonstrated experimentally with simultaneous transport of 1 Gbit/s baseband, 2.5 GHz microwave, and 37.5 GHz millimeter-wave signals that have the potential to converge last-mile optical and wireless technologies, leading to an integrated dense WDM network in the access and metro domains.
TL;DR: An overview of the most important classes of FEC codes is presented, assessing the most suitable to be used in time-division multiple access networks, and the Reed-Solomon codes were found to be the most appropriate.
Abstract: The use of forward error correction (FEC) codes in future deployments of access networks is quite foreseeable and requires an analysis of the proper code for this purpose. Therefore, an overview of the most important classes of FEC codes is presented, assessing the most suitable to be used in time-division multiple access networks. Concerning the traffic characteristics and the properties of such networks, the Reed-Solomon codes were found to be the most appropriate, and an analysis of the performance improvement obtained with these codes is reported. The upstream performance of 10 Gbits/s Ethernet passive optical network systems employing the selected FEC code is evaluated and the benefits of introducing FEC are assessed, aiming for the minimization of characteristic impairments of such networks.
TL;DR: In this paper, a 60 GHz radio-over-fiber (RoF) network using an electroabsorption modulator (EAM) is presented, where a photonic frequency upconversion technique that utilizes the wavelength conversion process in the EAM is adopted for seamless integration of optical and wireless networks.
Abstract: A 60 GHz radio-over-fiber (RoF) network using an electroabsorption modulator (EAM) is presented. A photonic frequency upconversion technique that utilizes the wavelength conversion process in the EAM is adopted for seamless integration of optical and wireless networks. The transmission characteristics of the quadrature amplitude modulation (QAM) coded data signal over the 60 GHz photonic-wireless link, which comprises the 50 km optical fiber transmission between the central station and the base station (BS) and the aerial transmission between the BS and the customer unit using horn antennas, are investigated by measuring the error vector magnitude (EVM) and its dependence on the EAM bias voltage. Optimized EVM values of 3.8% and 3.9% are obtained for 64-QAM and 16-QAM at an EAM bias of −0.8 V, respectively.