Power consumption modeling in integrated optical-wireless access network

The access segments of both optical and wireless networks are well known for their domination over the network’s total power consumption. Therefore, the study on energy consumption particularly in integrated optical-wireless access networks is crucial as energy consumption issue is increasingly vital nowadays. Existing works to date largely addressed the physical characteristics of integrated devices and algorithms for layer 2 and layer 3, where the study in power consumption modeling was often ignored. Hence, this thesis focuses on developing a power consumption model for integrated optical-wireless access networks and investigates the energy efficiency of such networks. Gigabit Passive Optical Network (GPON) as the optical backhaul and Worldwide Interoperability Microwave Access (WiMAX) and Long-Term Evolution (LTE) with femtocell application for the wireless network are considered. First, the power consumption model of the integrated network involving Optical Line Terminal (OLT) and integration between Optical Network Unit (ONU) and Base Station (BS) known as Integrated ONU-BS (IOB) are developed. Then, the power consumption behavior of ONU under different traffic loads has been investigated to model the total power consumption of integrated access networks. An empirical approach has been proposed to characterize the power consumption of the ONU by using real GPON testbed and to develop the power consumption model of ONU based on experimental results. This is followed by the extensive analyses that have been conducted to investigate the impact of various parameters such as split ratio, Femtocell Base Station (FBS) cell range, broadcast factor, and modulation and coding scheme into the total network power consumption and energy efficiency. It has been observed that GPONLTE has the worst energy efficiency performance when compared to GPON-WiMAX, even though it offers the highest data rates. The study has been further extended by including energy saving aspects where sleep mode techniques have been applied (i.e. power shedding for the ONU and idle mode procedure for FBS) based on the user behavior from the traffic profile pattern in Cyberjaya municipal broadband access networks. The implementation of energy saving techniques have shown further significant improvement of 15% lower energy consumption for the integrated access network

Determination of optimized sleep interval for 10 gigabit-passive optical network using learning intelligence

The overall aim of this project is to investigate the application of a machine learning method in finding the optimized length of asleep time interval (TAS) in a cyclic sleep mechanism (CSM). Since past decade, the implementations of CSM in the optical network unit (ONU) to reduce the energy consumption in 10 gigabit-passive optical network (XG-PON) were extensively researched. However, the newest era sees the emergence of various network traffic with stringent demands that require further improvements on the TAS selection. Since conventional methods utilize complex algorithm, this paper presents the employment of an artificial neural network (ANN) to facilitate ONU to determine the optimized TAS values using learning from past experiences. Prior to simulation, theoretical analysis was done using the M/G/1 queueing system. The ANN was than trained and tested for the XG-PON network for optimal TAS decisions. Results have shown that towards higher network load, a decreasing TAS trend was observed from both methods. A wider TAS range was recorded from the ANN network as compared to the theoretical values. Therefore, these findings will benefit the network operators to have a flexibility measure in determining the optimal TAS values at current network conditions

Self-configuration and self-optimization process with Taguchi method in hybrid optical wireless network

In this paper, an alternative improvement is proposed which is the adaptive wireless access networks-based optical backhaul convergence that will greatly promote to use the existing resource of MANET (mobile ad hoc network). However, these characteristics itself acts as a drawback to the MANET applications such as the random distribution of nodes and continuously changing topology. MiNiTab statistical software was used to model the effect of the parameter variation to predict the field quality through the design of experiments while OMNeT++ network simulation was created to visualize the effect of QoS performance study in response with varying speed scenario. The result shows that the proposed ESCMDR scheme can obtain robustness and outperformed compared to the nonTaguchi previous study when it is used in random waypoint mobility model in any speed of sources. The work is based on Packet Delivery Ratio (PDR) and Packet Loss Probability (PLP) metric under the varying speed scenario. It results in better QoS network PDR of 28.9% improvement, with 83.56% improvement on average PLP. The paper shows that the MANET QoS performance constrained can be addressed with the self-configured data rate of integrated optimization with Taguchi method on AODV-UU (Adhoc On Demand Distance Vector-Uppsala University) routing technique

Free space optical front-end receiver’s bandwidth enhancement employing micro-electro mechanical systems variable feedback capacitor

Free space optical front-end receiver usually suffers high photodetector input capacitance which limits the bandwidth of the system. This is due to the large detection area required to collect as much optical radiant power as possible to increase the system’s sensitivity. In this work, the bootstrap transimpedance amplifier (BTA) is adopted as an alternative approach for free space optical front-end receiver design. This technique offers the usual advantages of the transimpedance amplifier (TIA) together with the effective capacitance reduction technique. An improved photodetector model and the both front-end structures; TIA and BTA have been simulated using harmonic balance technique offers by Microwave Office, and the results show that the design improves the system bandwidth by 6.7 times in average. However, the performance of the BTA was found limited to a certain photodetector input capacitance. In order for the front-end structure to adapt with various photodetectors capacitance, MEMS variable capacitor (varicap) is introduced as a tunable feedback element for the bootstrap loop for an optimum performance. The MEMS varicap have been designed and modeled using CoventorWare and found to be practical for circuit implementation. The implementation of MEMS varicap with the design BTA optical front-end receiver was verified using the CoventorWare ARCHITECT. The simulation of the BTA employing MEMS variable capacitor as the feedback capacitor shows the improvement in bandwidth by 1.04 times in average for various photodetector input capacitance

Weight influence of logarithmic and exponential functions on the selection of wireless networks using multi-criteria decision-making methods

This research aims to study the influence of logarithmic and exponential functions on the multi-criteria decision-making algorithm that changesthe linear to the nonlinear method. It is carried out to better understand themulti-criteria decision-making (TOPSIS) algorithm whereby these functionsmay influence the criteria weights during the selection of the best network. Theexperiment is applied under different network types to evaluate the most optimumnetwork that leads to better throughput, low latency, minimum BER, andlow price per MB. The algorithms are assessed in MATLAB simulation environments.In addition, the adoption of the Wi-Fi networks standard is determined byfactors such as bandwidth, signal to noise ratio and the channel modulation techniqueduring the decision-making process. The simulation results showed thatthe exponential function had produced approximately similar results to that oflinear TOPSIS algorithm because both keep the weights to demonstrate positivevalues. However, logarithmic TOPSIS produced different results and a worstcasescenario, as the weights have negative values which lead to a phase shift of180° during the decision process. Thus, linear TOPSIS was found to have the bestresults while logarithmic TOPSIS had the worst outcome

Weight Influence of Logarithmic and Exponential Functions on the Selection of Wireless Networks Using Multi-Criteria Decision-Making Methods

This research aims to study the influence of logarithmic and exponential functions on the multi-criteria decision-making algorithm that changes the linear to the nonlinear method. It is carried out to better understand the multi-criteria decision-making (TOPSIS) algorithm whereby these functions may influence the criteria weights during the selection of the best network. The experiment is applied under different network types to evaluate the most optimum network that leads to better throughput, low latency, minimum BER, and low price per MB. The algorithms are assessed in MATLAB simulation environments. In addition, the adoption of the Wi-Fi networks standard is determined by factors such as bandwidth, signal to noise ratio and the channel modulation technique during the decision-making process. The simulation results showed that the exponential function had produced approximately similar results to that of linear TOPSIS algorithm because both keep the weights to demonstrate positive values. However, logarithmic TOPSIS produced different results and a worst-case scenario, as the weights have negative values which lead to a phase shift of 180⁰ during the decision process. Thus, linear TOPSIS was found to have the best results while logarithmic TOPSIS had the worst outcome

Series-shunt bootstrapping preamplifier circuit for free space optics

The signal level in an optical wireless receiver is weakest at the front-end due to the photo detector capacitance and appropriate design should be done to improve the receiver performance [1]. The optimum receiver performance can be achieved depends on the devices and design techniques used. Thus, this paper examines some of the issues involved in the design of front-end optical wireless receiver. Series-shunt bootstrap was investigated as the technique for mitigating the effects of the large capacitances associated with the photo detector. Optical wireless link or free space optics (FSO) require a large aperture and thus, the receiver is required to have a large detection area, which produces a high input capacitance and consequently reduced the bandwidth [1,2]. In order to maximize the bandwidth, we need to reduce Cin which is the summation of photodiode capacitance, Cd and amplifier input capacitance, Cs. On the other hand, it is necessary to reduce RL but the thermal noise element will increase when the load resistor is reduced