Hybrid Wireless-optical Access Network Research Articles

Last mile mobile hybrid optical wireless access network routing enhancement

This study focuses on mobile ad hoc networks (MANETs) that support Internet routing protocol imposing stringent resource consumption constraints of Quality of service (QoS). The mobile Internet causes the ongoing issue of inefficient use of the MANET resources due to its random nature of wireless environments. In this paper, the new improved architecture of the last mile mobile hybrid optical-wireless access network (adLMMHOWAN) is proposed and designed to tackle the arised issues. The proposed design is based on a unified wireless-wired network solution required the deployment of MANET-based wireless fidelity (WiFi) technology at the wireless front-end and wavelengths division multiplexing passive optical network (WDM PON) at the optical backhaul. The critical performance metrics such as network capacity and energy consumption based on modified AODVUU routing protocol using OMNeT++ software is analyzed with 2 scenarios, namely the number of nodes and mobility speed. This mode of communication results in better QoS network capacity of 47.07% improvement, with 26.85% reduction of lower energy resource consumption for mobile wireless front-end over passive optical network backhaul architecture when compared with the existing work of oRiq scheme that focus on improvement in MANETs.

Analysis of Next-Generation Multiuser Hybrid Optical Wireless Access Network (HOWAN) with Different Technologies; A Review

Today’s rapid speed internet demand has become high to satisfy the request of higher data rate and expensive transmission capacity another communication system required. Optical fiber is used to fulfill these demands. Optical communication is needed for higher speed data transmission. In optical fiber communication, multi carrier modulation (MCM) gives more attention instead of single carrier modulation (SCM). Orthogonal Frequency Division Multiplexing (OFDM) is a very attractive multiplexing and modulation technique that is used for both wireless and wired communication system. Advantages of optical orthogonal system are spectrum efficiency and channel robustness. Optical Orthogonal Frequency Division Multiplexing (OFDM), without complex Equalization can easily adjust to severe channel condition. This paper provides an overview of beginnings, different technologies and latest development of Next Generation of Passive Optical Network Keywords: Orthogonal Frequency Division Multiplexing (OFDM); Coherent receiving; Optical heterodyne; Passive Optical Network; Radio over Fiber (ROF); XG-PON; Multicast.

DIANA: A Machine Learning Mechanism for Adjusting the TDD Uplink-Downlink Configuration in XG-PON-LTE Systems

Modern broadband hybrid optical-wireless access networks have gained the attention of academia and industry due to their strategic advantages (cost-efficiency, huge bandwidth, flexibility, and mobility). At the same time, the proliferation of Software Defined Networking (SDN) enables the efficient reconfiguration of the underlying network components dynamically using SDN controllers. Hence, effective traffic-aware schemes are feasible in dynamically determining suitable configuration parameters for advancing the network performance. To this end, a novel machine learning mechanism is proposed for an SDN-enabled hybrid optical-wireless network. The proposed architecture consists of a 10-gigabit-capable passive optical network (XG-PON) in the network backhaul and multiple Long Term Evolution (LTE) radio access networks in the fronthaul. The proposed mechanism receives traffic-aware knowledge from the SDN controllers and applies an adjustment on the uplink-downlink configuration in the LTE radio communication. This traffic-aware mechanism is capable of determining the most suitable configuration based on the traffic dynamics in the whole hybrid network. The introduced scheme is evaluated in a realistic environment using real traffic traces such as Voice over IP (VoIP), real-time video, and streaming video. According to the obtained numerical results, the proposed mechanism offers significant improvements in the network performance in terms of latency and jitter.

Hybrid Optical–Wireless Access Networks

Next-generation access networks are expected to provide mobility, large data bandwidth, high quality of service (QoS), and ubiquitous coverage. Hybrid optical-wireless access networks will support these complementary features through high-capacity fiber subnetworks and flexible wireless subnetworks. As wireless access technologies progress, increased demand for access bandwidth and QoS will require a rapid evolution of fiber subnetworks and a tighter integration of the two technologies. This paper presents both radio-over-fiber transport technologies and novel architectures and technologies for hybrid optical-wireless networking. Basic optical systems for radio signals' transport use intensity modulation and direct detection. Advanced transport systems may utilize amplified links, coherent links, subcarrier transport, and digitized transport. They can be used to support powerful access solutions. On the networking side, diverse alternatives for hybrid access architectures are presented. Two wavelength division multiplexing (WDM)-based architectures, MARIN and GROWNet, are analyzed in detail. Both architectures dynamically support next-generation wireless access network traffic employing reconfigurable WDM technologies. MARIN is more technologically conservative and so is more suitable for near-future implementation. GROWNet is more technologically aggressive and is substantially more flexible and more powerful. Using hybrid network simulations, we demonstrate these architectures' capabilities to dynamically balance wireless traffic and to coordinate wireless transmission. We also review other research efforts in this field including ACCORDANCE, FiWi, FUTON, and WOBAN. Remaining challenges and research topics are also discussed to motivate further investigations into optical-wireless access networks.

Performance Analysis Of Hybrid Optical–Wireless Access Network Physical Layer

The hybrid optical–wireless access network (HOWAN) is a favorable architecture for next generation access network. It is an optimal combination of an optical backhaul and a wireless front–end for an efficient access network. In this paper, the new architecture of the HOWAN is proposed and designed based on both a wavelengths division multiplexing/time division multiplexing passive optical network (WDM/TDM PON) at the optical backhaul and a worldwide interoperability for microwave access (WiMAX) technology at the wireless front–end. It is demonstrated 2 Gb/s for downstream/upstream can be achieved at optical backhaul along 20 km of single mode fiber (SMF) for each wavelength channel with bit error rate (BER) of 10–9, at a data rate of 30 Mb/s per Base Station (BS) along a 5 km outdoor wireless link with BER of 10–5. Key words: Hybrid optical–wireless access network (HOWAN); Passive optical network (PON); Wavelength division multiplexing (WDM); Wireless mesh network (WMN); Orthogonal frequency division multiplexing (OFDM)

Analysis of physical layer performance of hybrid optical–wireless access network

The hybrid optical–wireless access network (HOWAN) is a favorable architecture for next generation access network. It is an optimal combination of an optical backhaul and a wireless front-end for an efficient access network. In this paper, the HOWAN architecture is designed based on a wavelengths division multiplexing/time division multiplexing passive optical network (WDM/TDM PON) at the optical backhaul and a wireless fidelity (WiFi) technology at the wireless front-end. The HOWAN is proposed that can provide blanket coverage of broadband and flexible connection for end-users. Most of the existing works, based on performance evaluation are concerned on network layer aspects. This paper reports physical layer performance in terms of the bit error rate (BER), eye diagram, and signal-to-noise ratio (SNR) of the communication system. It accommodates 8 wavelength channels with 32 optical network unit/wireless access points (ONU/APs). It is demonstrated that downstream and upstream of 2 Gb/s can be achieved by optical backhaul for each wavelength channel along optical fiber length of 20 km and a data rate of 54 Mb/s per ONU/AP along a 50 m outdoor wireless link.

S2U: An efficient algorithm for optimal integrated points placement in hybrid optical-wireless access networks

Integration of optical and wireless networks is considered as one of the promising technologies for next generation Internet access. In this paper, we consider the integrated points placement problem in the hybrid optical-wireless system for optimal resource utilization under the given constraints including hop count, cluster size, and relay load. While the optimization formulation is an NP-hard problem in general, we propose a polynomial-time heuristic algorithm – S 2 U algorithm to obtain the near-optimal solution that minimizes the number of integrated points required to support all wireless BSs residing in the wireless part of the integrated system. In contrast to the existing work, our S 2 U algorithm forms the clusters starting from the network edge towards its center and the construction of clusters is not only based on the greedy idea but also considers load balancing. We present a theoretical analysis of the complexity of the proposed S 2 U algorithm and its approximation ratio to the optimal solution. Furthermore, we present extensive numerical results to compare the proposed S 2 U algorithm with the main existing methods. It is shown that S 2 U can not only cover a network with a smaller number of integrated points, but also achieve better network performance in terms of the average transmission delay (average hop count) and load balance. In addition, we compare our results with the optimal solution obtained via CPLEX in terms of the minimum number of integrated points. The results show that the gap between the results obtained from our S 2 U algorithm and the optimal results is within 5% in average.

Combined Analysis of OFDM-UWB Transmission in Hybrid Wireless-Optical Access Networks

The hybrid wireless-optical transmission of ultra-wideband signals employing orthogonal frequency-division multiplexing modulation (OFDM) ultra-wideband (UWB) as defined in the ECMA-368 standard is experimentally analyzed in this letter. The OFDM-UWB signals provide 400 Mb/s per user at optical distances from 5 to 50 km on standard single-mode fiber (SSMF). The analysis includes the wireless radiation from 0 to 3 m after optical transmission. The results indicate a maximum error-vector-magnitude degradation of 2.5 dB measured at 1.5-m radio after 50-km SSMF optical transmission for the first two UWB channels. This degradation translates to 1-m maximum wireless-reach penalty.

Hybrid Architecture and Integrated Routing in a Scalable Optical–Wireless Access Network

We propose a hybrid optical-wireless access network that consists of reconfigurable optical backhaul and wireless mesh networks (WMNs). The complementary characteristics of wireless and optical networks are combined to provide a broadband and ubiquitous last-mile connection. Wireless mesh routers are deployed to penetrate the vicinity of end users for a flexible and ubiquitous connection. It eliminates massive and geographically scattered deployment of physical infrastructure to reach the end users. The broadband optical backhaul consists of optical ring and multiple tree networks, connecting the central hub and WMNs. The ends of the optical tree networks connect to the wireless gateway routers of WMNs. A hybrid time-division-multiplexing (TDM)/wavelength-division-multiplexing (WDM) optical backhaul is realized by wavelength-multiplexing multiple TDM-passive-optical-network streams. This hybrid architecture provides graceful scalability, cost effectiveness, and bandwidth efficiency. To adapt to a change of the overall demand in different districts, reconfigurability is implemented in the optical backhaul utilizing tunable optical transceivers. An experimental test bed is implemented to evaluate the reconfigurable scheme. Given the synergy of the optical backhaul and WMNs, we propose an integrated-routing algorithm to achieve load balancing on this hybrid architecture. The simulation using NS2 shows an approximately 25% throughput improvement with load balancing.

Key Enabling Technologies for Optical–Wireless Networks: Optical Millimeter-Wave Generation, Wavelength Reuse, and Architecture

The integration of optical and wireless systems is considered to be one of the most promising solutions for increasing the existing capacity and mobility as well as decreasing the costs in next-generation optical access networks. In this paper, several key enabling technologies for hybrid optical-wireless access networks are described, including optical millimeter-wave (mm-wave) generation, upconversion, and transmission in a downlink direction, and full-duplex operation based on wavelength reuse by using a centralized light source in an uplink direction. By employing these enabling technologies, we design and experimentally demonstrate an optical-wireless testbed that is simultaneously delivering wired and wireless services in the integrated optical-wireless and wavelength-division-multiplexing passive-optical-network access networks. The actual applications consisting of 270-Mb/s uncompressed standard-definition TV signal and 2.5-Gb/s data channels for downstream are successfully transmitted over a 25-km fiber and a 10.2-m indoor wireless link with less than a 1.5-dB power penalty. The results show that this integrated system is a practical solution to deliver superbroadband information services to both stationary and mobile users.