Uma Rathore Bhatt

Survivability of a integrated fiber-wireless (FiWi) access networks

In past few years there is a huge development in the field of FiWi technology due to continuously increase in the number of users of the internet. FiWi technology now a days proving itself a main tool in the field of telecommunication by its own merits over the other existing technologies. The FiWi technology provides huge amount of bandwidth and stability to the network user in a flexible manner i.e. network provide “Anywhere Anytime” connection service to the user at very high speed. The existing technology viz PON offers higher bandwidth and stability but at relatively higher cost due to the use of expensive optical devices. On the other hand WMN technology offers us communication among the users with a better flexibility at relatively lower cost but its bandwidth is limited due to channel interference. So, the efforts are put to combine the merits of both the technologies resulting in a new technology named as “FiWi”. Various algorithms are proposed to enhance the performance of a FiWi access network. In this paper, a detailed discussion is made on survivability issues in FiWi networks against the different level of failures in the network. This paper is basically a review paper in which the main aim is to emphasize on the recent trends of survivability in the FiWi networks.

ONU placement in Fiber-Wireless (FiWi) access networks using teacher phase of Teaching Learning Based Optimization (TLBO) algorithm

Nowadays, there is a huge requirement of bandwidth and mobility to end users. For fulfilling this, Fiber-Wireless (FiWi) networks are designed consolidating the advantages of both optical and wireless networks. Optical networks provide high bandwidth and stability while wireless networks provide cost efficiency and mobility. In FiWi networks Optical Network Units (ONU) placement is a very important issue since ONU links both optical and wireless end of the network. Reducing ONUs in the network directly leads to cost efficiency of that network. For the same purpose, we implement an algorithm based on teacher phase of Teaching Learning Based Optimization (TLBO). The implemented algorithm reduces required ONUs in the network.

Fiber-wireless (Fi-Wi) architectural technologies: A survey

The paper aims to present various architectural technologies of Fiber-Wireless (Fi-Wi) networks, based on previous and current interest of researchers. Fi-Wi networks recently become more powerful & impactful in the access technology solution & prototypes. The survey overviews the architectural knowledge & enabling technologies involved and comparing it with future development of wireless & optical network respectively. Radio-over-Fiber (RoF) transmission is used to achieve high level of integration with simplified wireless base station. On the other hand Radio-and-Fiber (R&F) networks are the most beneficial architecture implementation which is used to build Wireless Local Area Network (WLAN) based Fi-Wi networks.

MIKBIT- Modified DSR for MANET

Various reactive and proactive routing protocols are being used in Mobile ad hoc networks (MANETs). Dynamic Source Routing (DSR) is one of the reactive routing protocols but high overhead involved in flooding while route creation is a limiting factor of DSR protocol. The paper aims to minimize the number of route requests (RREQs), which is a significant source of overhead for the DSR. In this paper, the modification of DSR algorithm is done to enhance its performance. In the proposed modified DSR i.e. Mobile internetwork broadcast infrastructure technique (MIKBIT) multicasting approach is used to reduce packet overheads. The considered network is IEEE 802.15.4, which is the emerging next generation wireless standard designed for low-rate wireless personal area networks (LR-WPAN). The performance parameters such as throughput, average end-to-end delay, average jitter and packet delivery ratio are evaluated for the proposed algorithm and compared with that of existing DSR routing protocol. Substantial improvement is achieved using the proposed algorithm.

Investigation effect of phase noise of OFDM system and realization LO (local oscillator) with and without phase locked loop (PLL)

A phase locked loop (PLL) operates on the serialized received modulation symbols and provides an independent phase correction value for each received modulation symbol. Each received modulation symbol is corrected with its own phase correction value to obtain a phase-corrected symbol. The phase error in each phase-corrected symbol is detected to obtain a phase error estimate for that phase-corrected symbol. Orthogonal Frequency Division Multiplexing (OFDM) technique has received a great attention and has been widely used in the wireless communication systems for its high spectrum efficiency and robustness to the narrowband interference and multipath fading. OFDM can provide enormous data rates with sufficient robustness to radio channel impairments. Orthogonal frequency division multiplexing is one of the multi-carrier modulation (MCM) techniques that transmit signals through multiple carriers. These carriers (subcarriers) have different frequencies and they are orthogonal to each other. But it yields however some disadvantages too, one being an increased sensitivity to phase noise, which is generated in the local oscillators. The phase-corrected symbols are not correlated because independent phase correction values are used for the received. In this Paper, We are investigating the effect of phase noise upon OFDM system and realized local oscillator (LO)by using phase locked loop (PLL)[1][2]. Then system performance is evaluated as a degradation of the effective signal-to-noise ratio due to phase noise, in terms of BER simulations with and without PLL for different channel conditions.

Survivable Routing and Wavelength Assignment Strategy for Multiclass WDM Optical Networks

All optical WDM networks which are capable to provide multiple classes of services, we present survivable routing and wavelength assignment strategy. Different class of services are likely to be formed according to subscriber requests like bandwidth requirement, expected call holding time, average arrival rate of request etc. For such kind of multi class WDM networks where the survivability is an important issue, we propose a strategy which is capable to provide 100% protection to connection request and improved system performance. The proposed strategy (strategy 2) has been analyzed for multiclass traffic scenarios. Simulation results on different network topologies demonstrate that the performance of proposed strategy give satisfactory performance as compared to existing strategies (no protection and strategy 1) in terms of blocking probability using limited number of wavelengths with 100% survivability.

A Review of Recent Energy-Efficient Mechanisms for Fiber-Wireless (FiWi) Access Network

Fiber-wireless (FiWi) access network is a category of networks which utilize optical network’s bandwidth and wireless network’s flexibility. This last mile technology will serve all needs of access networks for many years to come. However, its energy consumption has also been increased rapidly due to the development of high bandwidth application like Internet of Things (IoT). Therefore, it has become critically important to discuss the energy-related issue for FiWi. Based on the literature, this chapter provides an exhaustive survey of recent progress on energy efficiency mechanisms such as ONU sleeping mechanisms, power saving modes (PSM), and some cooperative-based energy saving schemes. Furthermore, it also provides future directions for better energy efficiency in FiWi network.

Low Delay Routing Algorithm for FiWi Access Network

Fiber wireless FiWi access network is an integration of two networks. The first part of network is called passive optical network (PON), used at backend. The second part of network, wireless mesh network (WMN) is used at front end. This combination facilitates high data rates, stability, and flexibility. Routing is very important part of wireless mesh network (WMN), and therefore of FiWi access network. It directly affects the network parameters such as throughput, delay, packet delivery ratio which in turn affects the network performance. In this paper, a routing algorithm is proposed for FiWi network, on the basis of minimum angle criteria. The algorithm results in lesser delay as compared to standard routing algorithm.

Efficient Placement of ONUs via Ant Colony Optimization Algorithm in Fiber-Wireless (FiWi) Access Networks

FiWi is a fusion of optical network and wireless network. It gives high bandwidth, high data rates, high mobility, and low cost. The connection interface between the PON and WMN is established by the use of an optical network unit (ONU). ONU is an important component of communication as well as it affects the overall cost of system, hence its placement in the network becomes an important issue. Various research works have already been done to provide the solution. We aim to present a new optimizing algorithm for ONU placement and its minimization; this will result in the enhancement of network performance and reduction in the cost of overall network.

Analysis of wavelength conversion in wavelength routed WDM networks

In order to achieve the improved blocking performance of wavelength routed WDM networks, wavelength conversion can be implemented at nodes. The paper evaluates the performance of the network in terms of blocking probability with and without wavelength conversion. The analysis and comparison for wavelength conversion and without wavelength conversion has been undertaken for static and dynamic traffic. It is observed that with wavelength conversion blocking probability reduces significantly. The underlying system model is presented for wavelength conversion and without wavelength conversion. Simulation results also suggest the optimal value of resources for each case.