Enhancing Teaching and Learning Wi-Fi Networking using Limited Resources to Undergraduates

Teaching wireless networking fundamentals is often difficult because many students appear to find the subject technical, and dry when presented in traditional lecture format. To overcome this problem, we provide an opportunity for experiential learning where students can learn wireless networking fundamentals by hands-on practical activities using low-cost Wi-Fi (wireless fidelity) devices such as wireless cards and access points. Students can easily set up and configure networks using wireless cards and access points more effectively. By measuring network performance such as throughput and end-to-end delays, students are able to gain a deeper understanding of wireless networking. The effectiveness of Wi-Fi-based practical activities has been evaluated by students and the teaching team. This chapter reports on the overall effectiveness of teaching and learning of wireless network using radially available low-cost Wi-Fi cards and access points.

We leverage stochastic geometry to characterize key performance metrics for neighboring Wi-Fi and LTE networks in unlicensed spectrum. Our analysis focuses on a single unlicensed frequency band, where the locations for the Wi-Fi access points (APs) and LTE eNodeBs (eNBs) are modeled as two independent homogeneous Poisson point processes. Three LTE coexistence mechanisms are investigated: (1) LTE with continuous transmission and no protocol modifications; (2) LTE with discontinuous transmission; and (3) LTE with listen-before-talk (LBT) and random back-off (BO). For each scenario, we have derived the medium access probability (MAP), the signal-to-interference-plus-noise ratio (SINR) coverage probability, the density of successful transmissions (DST), and the rate coverage probability for both Wi-Fi and LTE. Compared to the baseline scenario where one Wi-Fi network coexists with an additional Wi-Fi network, our results show that Wi-Fi performance is severely degraded when LTE transmits continuously. However, LTE is able to improve the DST and rate coverage probability of Wi-Fi while maintaining acceptable data rate performance when it adopts one or more of the following coexistence features: a shorter transmission duty cycle, lower channel access priority, or more sensitive clear channel assessment (CCA) thresholds.

Hybrid light fidelity (LiFi) and wireless fidelity (WiFi) networks (HLWNets) have been recently proposed as a promising technique for indoor wireless communications. Such a network combines the high-speed transmission of LiFi and the ubiquitous coverage of WiFi. Meanwhile, in addition to user mobility, intermittent light-path blockages make the handover issue intricate in HLWNets. Also, load balancing (LB) is necessary because the coverage areas of LiFi and WiFi networks are completely overlapped. This further increases the difficulty in handover as the decision for a vertical or a horizontal handover in a mobile environment with ultra-small cells is non-trival. Aimed at providing an optimal solution to the access point selection (APS) with given channel state information (CSI), the conventional LB method might cause frequent and unnecessary handovers. In this paper, a joint optimisation problem is formulated to simultaneously consider LB and handover in HLWNets. Results show that compared with the conventional LB method, the proposed method can improve the system throughput by up to 60%.

Wi-Fi networking has been becoming increasingly popular in recent years, both in terms of applications and as the subject of academic research papers and articles in the IT press. It is important that students grasp the basic concepts of both Wi-Fi networking and wireless propagation measurements. Unfortunately, the underlying concepts of wireless networking often intimidate students with their apparently overwhelming complexity, thereby discouraging the students from learning in-depth this otherwise exciting and rewarding subject. This chapter provides a tutorial on Wi-Fi networking and radio propagation measurements using wireless laptops and access points. Various hands-on learning activities are also discussed.

With the astronomical growth in online presence vis-a-vis the IT industry across the globe, there is an urgent need to evolve cloud based DataCenter architectures that can rapidly accommodate web application integrations which can serve the energy industries, educational sector, finance sector, manufacturing sector, etc. Previous works in DataCenter domain have not investigated on cloud based DataCenter Servercentric characteristics for evaluation studies. This paper then proposed a Reengineered DataCenter (R-DCN) architecture for efficient web application integration. In this regard, attempt was made to address network scalability, efficient and distributed routing, packets traffic control, and network security using analytical formulations and behavioural algorithms having considered some selected architectures. In this work a simulation experiment was carried out to study six key performance metrics for all the architectures. It was observed that the network throughput, fault-tolerance/network capacity, utilization, latency, service availability, scalability and clustering effects of R-DCN responses with respect to above Key Performance (KPIs) metrics were satisfactory when compared with BCube and DCell architectures. Future work will show a detailed validation using a cloud testbed and CloudSim Simulator.

Performance analysis for MU-MIMO enabled LTE-U networks coexisting with D2D and WiFi network

Light Fidelity (LiFi) is a form of Visible Light Communication (VLC) that provides high-speed, bidirectional and fully networked wireless communication systems using low power Light Emitting Diodes (LEDs) light bulbs. As a reliable, license-free, high-speed and fully bi-directional wireless networked, LiFi is a potential technology to the Radio Frequency (RF) based systems and beyond mobile networks. As the spectrum utilized by Li-Fi does not overlap with that of used by the RF, a hybrid LiFi and wireless fidelity (WiFi) networks can provide high-speed data transmission that will improve the Quality of Service (QoS) and Quality Experience (Qoe) of the internet users. However, in such hybrid network systems, intermittent light-path blockages and user mobility may degrade the system throughput due to frequent handover among the networks. Different mechanisms to mitigate the frequent handover issue in hybrid LiFi and WiFi networks have been proposed in the literature. This paper provides an overview concept of hybrid handover in LiFi/WiFi networks. Furthermore, related works done in this field are also discussed. Finally, comparison between LiFi and WiFi technologies is also provided.

The quality of service (QoS) in a Wireless Fidelity (WiFi) network can not be guaranteed due to intermittent disconnections, interferences and so forth because they reduce considerably the necessary QoS for multimedia applications. For that reason it is essential a software as the one we present in this paper that evaluates if there are the appropriate conditions to receive the streaming measuring the congestion, radio coverage, throughput, lost and received packets rate, and so on. Our software makes a proactive estimation using a bottom-up cross-layer technique measuring physical level parameters, Round Trip Time (RTT) and getting traffic statistics for the overall WiFi network and for each ongoing Real Time Streaming Protocol/Real Time Protocol (RTSP/RTP) streaming session. Experimental results show a high percentage of good decisions of the software to detect the wireless channel degradation and its recovery.

Wi-Fi networks are becoming more and more ubiquitous and represent a substantial source of energy consumption around the globe, mainly when it comes to Access Points (APs). There has been some work done on the characterization of the power consumption of Wi-Fi APs and network interface cards (NICs), and the power usage of these devices under different configurations and standards but mostly using legacy standards. A detailed AP power consumption analysis, exploring the whole set of degrees of freedom and capabilities of these devices is lacking in the state of the art. In this paper, we present a thorough power consumption analysis, covering the configuration options available in enterprise Wi-Fi APs from the three major vendors on the market. The goal is to understand how the power consumption of an AP varies with the different configurations, and provide insights on the parameters that significantly affect the AP power consumption. The obtained experimental results confirm previous state-of-the-art conclusions but contradict some of the studies and results found in the literature, while updating results and conclusions taken in the past to the most recent standards, configurations, and data rates available today. The analysis provided herein is a valuable source of information for deriving new AP power consumption models and designing energy-efficient Wi-Fi networks.

Wireless fidelity (WiFi) networks are deployed in several varied environments all around the World. Usually, the wireless fidelity access points are always on in houses and other small companies. In buildings of large companies and public organizations and in university campuses the number of access points is elevated; they are powered using power over the ethernet and are always on. Consequently, they consume a considerable amount of electric energy. The last versions of the International Electric and Electronic Engineers 802.11 standardized procedures to save energy in a wireless fidelity terminal but not in the access point. We designed a formal method to show when energy can be saved in wireless fidelity access points considering different power supplies for the access point: an electric energy battery and a standard voltage supply. We use an external battery that stores electric energy during an interval of time from a standard voltage supply (Charge period). After that interval (Discharge period), the energy supply for the access point is the external battery. Those intervals of time are repeated sequentially (Charge and Discharge cycles). We verified our formal model implementing a hardware circuit that controls the power supply for the access point. The amount of energy saving for a large number of of access points during a long period of time is considerably high.

Wi-Fi is the dominant infrastructure for last-mile internet access both in indoor and outdoor environments. The existing Wi-Fi infrastructure leverages to offer IoT services. Despite the growth and popularity of Wi-Fi, security is a significant concern associated with it. One such issue with the Wi-Fi network is Evil Twin Attack (ETA). In ETA, the adversary creates an Evil Twin AP (EAP), a copy of Legitimate Access Point (LAP), for the user to connect. Once the user connects to EAP, the adversary can perform various attacks. Enterprise networks can solve ETA with the help of certificate-based server authentication using 802.1X and Extensible Authentication Protocol. However, there is no proper solution to detect ETA in Wi-Fi personal networks. Latest Wi-Fi security algorithms, namely Wi-Fi Protected Access 3 (WPA3) and Opportunistic Wireless Encryption (OWE) also vulnerable to ETA. This paper proposes a novel Proof of Existence (PoEx) scheme, bringing network lifetime to Access Point (AP). Wi-Fi client devices will detect and prevent ETA using associated AP lifetime. We apply the proposed PoEx scheme on WPA3 and OWE and show the security improvements. Our experiment results show that lifetime forging is difficult due to an exponential number of computations (2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(N-1)</sup> ) required. The experimental result also shows negligible overhead (less than 2%) on throughput when the PoEx solution is enabled.

Recently, in conjunction of classical spectrum reuse techniques, multi-tenant concept where a single access point (AP) is used by Service Set Identifiers (SSIDs) of different operators, have been used to improve the density and thus the throughput of wireless networks. In this paper, we propose spectrum and SSIDs controller to maximise the network throughput in multi-tenant WiFi networks. The controller takes Received Signal Strength Indicators (RSSIs), received from surrounding multi-tenant APs (M-APs) and nearby STAs as the inputs. The proposed controller uses a learning automata scheme to allocate these resources to each M-AP in parallel. Experimental prototypes for the M-APs and controller are developed by using Software-defined Radio (SDR) kits. Our experiments indicate that the network throughput of the proposed system remains the same with an increasing number of tenants, in contrast with other existing schemes that shows a linear decrease in the network throughput.

With the expansion in the use of IoT, increasing the efficiency of these networks has become even more significant. Objects need reliable communications at suitable speed to be able to reach the expected performance. In a heterogeneous network of IoT, the objects can include users and related devices. Despite the hybrid Li-Fi and Wi-Fi networks, IoT needs were somewhat met. However, the efficiency of these networks depends on the choice of access points at the network level. In this study, a new algorithm was proposed based on the access point selection model, considering the strategic behavior of the objects and users. In this algorithm, inspired by access point selection model, a new adaptive algorithm was selected by choosing the access point by Markov game to enhance the load balancing and efficiency in IoT networks based on Wi-Fi and Li-Fi combination. According to the simulation results, it is seen that the proposed method could greatly increase the efficiency of IoT network and better distributes network load between access points with different technology. Overall network throughput was estimated at an average of at least 10% compared to the load-balancing method with fuzzy logic approach proposed in before research.

기존의 보안 Wi-Fi 네트워크는 사용자가 AP(Access Point)의 암호에 맞춰야 하므로 사용이 불편하며, 사용자들이 암호를 공유하므로 시간이 갈수록 보안성이 낮아지는 문제점을 갖고 있다. 이를 해결하기 위해 사용자마다 별도의 가상 Wi-Fi 네트워크를 할당하는 방안을 제안한다. 이 방법에서는 각 사용자가 자신만의 Wi-Fi 네트워크를 가지므로 사용자 중심의 네트워크 설정이 가능하다. 사용자는 자신의 기기에 나름대로의 SSID(Service Set IDentifier)와 암호를 미리 설정해 두며 AP는 자신의 공개키를 적절한 방법으로 공개한다. AP는 또한 사용자들이 언제나 접속할 수 있는 공개채널을 유지한다. 사용자 요청이 있을 때 사용자 기기는 연결 요청 메시지를 보내는데 이 메시지에는 AP의 공개키로 암호화된 사용자 기기의 SSID와 암호가 실려 있다. 연결 요청 메시지를 받은 AP는 해당 SSID 및 암호가 설정된 새로운 가상의 AP를 생성하는데 이 가상 AP는 해당 사용자만 사용할 수 있는 전용 AP라고 할 수 있다. 이렇게 만들어지는 가상 네트워크는 비밀번호를 여러 사용자가 공유하지 않으므로 보안성이 높다. 또 이 가상 네트워크는 네트워크가 사용자 기기에 맞춰 스스로를 설정하기 때문에 사용의 편의성이 높다. 새 방법이 제공하는 보안성과 편리성에도 불구하고 기존의 Wi-Fi 네트워크에 비해 별다른 전송 능력 저하는 나타나지 않음을 실험을 통해 확인하였다. Existing Wi-Fi networks require users to follow network settings of the AP (Access Point), resulting in inconveniences for users, and the password of the AP is shared by all users connected to the AP, causing security information leaks as time goes by. We propose, in this work, a personalized secure Wi-Fi network, in which each user is assigned her own virtual Wi-Fi network. One virtual Wi-Fi per user makes the user-centric network configuration possible. A user sets a pair of her own SSID and password on her device a priori, and the AP publishes its public key in a suitable way. The AP also maintains an open Wi-Fi channel, to which users can connect anytime. On user's request, the user device sends a connection request message containing a pair of SSID and password encrypted with the AP's public key. Receiving the connection request message, the AP instantiates a new virtual AP secured with the pair of SSID and password, which is dedicated to that single user device. This virtual network is securer because the password is not shared among users. It is more convenient because the network adapts itself to the user device. Experiments show that these advantages are obtained with negligible degradation in the throughput performance.

Wi-Fi networks are largely served using over-the-counter commodity Wi-Fi routers, access points (APs), and possibly with wireless controllers. Existing approaches to bring the benefits of Software-defined Networking (SDN) to such Wi-Fi networks suffer from availability, hardware requirements, and scalability issues. For instance, these approaches do not support enterprise APs whose firmware cannot be modified. Furthermore, we observe that using SDN controllers for managing all the flows traversing these APs and routers requires more than just installing an SDN switch on these devices. In this paper, we present our solution called SWIFT: Software-defined Wi-Fi Flow Management, for bringing SDN-based flow management to Wi-Fi networks using commodity Wi-Fi APs, Wi-Fi routers, and Wi-Fi controllers. We also detail its benefits, shortcomings, and possible use cases. Specifically, our solution significantly lowers the barrier-to-entry for deploying and conducting research on software-defined Wi-Fi networks.