Medium access control and network planning in wireless networks

Future wireless networks (FWNs) are expected to be a convergence of different kinds of wireless technologies, such as cellular technologies, wireless local area networks (WLANs), wireless metropolitan area networks, wireless sensor networks, and traditional wired networks. The internet protocol (IP) will be potentially adopted as the common networking protocol for diverse networking technologies including the next generation of cellular networks using system architecture evolution (SAE). However, the IP architecture has several known challenges, such as mobility, multihoming, routing scalability, location privacy, path preference selection, etc. One of the greatest problems preventing the networks from overcoming these challenges is that the IP address is contextually overloaded, both as locators and identifiers. As a result, in this paper, we describe the issues of all-IP wireless networks, and survey recent proposals focusing on IP address overloading that can be applied to FWNs.

The proliferation of Wireless Local Area Networks (WLANs) facilitates the development of multihop routing protocols. Moreover, the need to cover greater areas has led to the creation of new standards for Wireless Metropolitan Area Networks (WMANs). This paper proposes a new routing protocol that integrates WLANs and WMANs, allowing seamless interconnectivity.

The explosive growth of the Internet over the last decade has led to an increasing demand for high-speed, ubiquitous Internet access. Broadband wireless technologies are increasingly gaining popularity by the successful global deployment of the wireless personal area networks (Bluetooth-IEEE 802.15.1), wireless local area networks (WiFi- IEEE 802.lln), and wireless metropolitan area networks (WiMAX- IEEE 802.16). New ICT and e-Learning strategies and advances in wireless standards and technologies- particularly in the areas of Bluetooth, WiFi (wireless fidelity), WiMAX (worldwide interoperability for microwave access) and mobile computing can help to bridge the digital divide in education and research. Using open broadband Wireless technologies and implementing mobile computing architectures, one can overcome the challenges of ground, infrastructure, and finance to increase access; deploy broadband quickly and cost-effectively to areas currently not served; and extend the benefits of digital revolution to previously unreachable populations. These technologies aim to provide low-cost, high-performance Wireless access to residential and business applications. As technology evolves to address portable and mobile applications, the required features and performance of the system will increase. Evolution toward the phase called "full mobility" provides incremental support for low latency, low packet loss and real-time handoff of subscriber terminals operating at high speeds. This paper presents the analogy of promising wireless technologies on different frequencies: Bluetooth, WiFi, and WiMAX. This paper is organised into four parts: part I describes the functionality and usage of Bluetooth in the wireless personal area networks, part II presents the WiFi- IEEE 802.1 In strategies for users considering higher-bandwidth alternatives to existing wireless personal area networks, part III discusses how the WiMAX is used as a current standard for Wireless data transmission technology, which is optimized to deliver high, bursty data rates to mobile subscribers, and to support real-time multimedia and Voice over IP (VoIP) applications, and part-TV explores how these emerging Wireless technologies differ from one another.

Wireless communication provides users many benefits such as portability, flexibility, reduced hardware need and lower installation costs. Wireless local area networks (WLANs) for example allow users the ability to carry their laptops from place to place without any physical wires and without losing network connectivity.However, some amount of security risk is always associated with wireless networks. The most significant security risk for wireless technology is the potential outsiders have in gaining access to the communications medium, the communications medium being the air waves. Though WLANs provide the users with the option of roaming, this convenience is facilitated by broadcasting packets to anyone with compatible equipment within range of a transmitting device. This broadcasting of packets induces a compromise between convenience and security. Having an unsecured WLAN can result in a loss of service, or can be used as a staging area to launch attacks against other networks. The significant challenges faced today in securing wireless LANs are maintaining privacy, data confidentiality, and preventing unauthorized access using proper access control mechanisms.As wireless networking and security become more prevalent in the market, more and more computer science programs are incorporating courses in wireless networks or at the least, devoting a significant percentage of the advanced networking courses to wireless topics. As a result, in addition to industry practitioners, there is a growing interest among university researchers and faculty regarding tools used in monitoring and assessing security threats for wireless networks.This paper will demonstrate and evaluate a free and open source software tool, called Network Stumbler, used for monitoring and assessing security threats for wireless networks. Network Stumbler is a Windows-based tool that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g. It has many uses:• Verifies that your network is set up the way you intended.• Find locations with poor coverage in your WLAN.• Detects other networks that may be causing interference on your network.• Detects unauthorized rogue access points in your workplace.• Helps aim directional antennas for long-haul WLAN links.• Can be used recreationally for WarDriving.

To satisfy the stringent requirement of capacity enhancement in wireless networks, cooperative relaying is envisioned as one of the most effective solutions. In this paper, we focus on the problem of capacity enhancement by way of relay stations (RSs) placement, which is a critical task of network planning and deployment to achieve an efficient and scalable network design. To fully exploit the performance benefits of cooperative relaying, we develop an optimization framework to maximize the capacity as well as meet the minimal traffic demand for each subscriber station (SS). The problem of joint RS placement and bandwidth allocation is formulated into a mixed integer nonlinear program and solved through a heuristic approach based on genetic algorithm (GA). Moreover, an upper bound on the capacity is derived to assist the estimation of system performance given a network configuration. Numerical results are presented to demonstrate the effectiveness of the solution approach and the performance benefits due to RS placement and optimal bandwidth allocation through cooperative relaying.

Wireless mesh networks (WMNs) aim to solve the limitations and consequently to improve the performance of ad hoc networks, wireless local area networks (WLANs) and wireless metropolitan area networks (WMANs). In this paper we introduce a new routing metric for WMNs, which is called LTA (link type aware) metric. Unlike former metrics, LTA considers the special structure of WMNs and uses different link type among nodes to represent link quality. Without additional costs, LTA can be applied to most existing routing protocols. We imply LTA on AODV and compare the performance with mini-hop metric by simulation. Simulation results show that LTA metric can find reliable routes and reduce link-broken times in typical WMNs scenarios

The use of multiple antennas at both sides of the communication channel strongly improves the performance of the wireless communication system, increasing spectral efficiency and/or channel reliability. These advantages are very suitable for wireless local area networks (WLAN) and wireless metropolitan area networks (WMAN). This paper focuses on the study of fixed wireless broadband access (FWBA) services in metropolitan areas, making two main contributions. First, the experimental characterization of a 2times2 MIMO channel at a frequency of 2.4 GHz in canonical outdoor-indoor scenarios is presented. The channel characterization performed includes the analysis of the spatial correlation between the MIMO system subchannels and its impact on the channel capacity. Second, on the basis of the capacity results obtained, a proposal is made for the use of a 2times2 MIMO system in outdoor-indoor scenarios for FBWA applications in metropolitan environments. The proposal is based on the hypothesis, verified experimentally, that the path loss due to building penetration can be practically compensated by the diversity gain of 2times2 systems

Recent demands on affordable, portable wireless communication and computation devices have resulted in exponential growth of wireless networks ranging from Wireless Local Area Networks (WLAN) and Wireless Wide Area Networks (WWAN) to Ad-Hoc and Sensor networks. The major goal of wireless communication is to allow users to communicate together and to have access to global network anytime anywhere. This has led to wide acceptance of infrastructure based cellular networks (WWANs) where mobile stations communicate with a centralized controller, often referred as Access Point (AP) that is connected to the wired networks. On the other hand, WLANs have appeared as dominant popular technologies in many venues including a local area such as an academic campus or an airport terminal. These wireless networks mostly rely on IEEE 802.11 Wi-Fi (Wireless Fidelity) technology and its various derived versions (i.e. 802.11a,b,g). IEEE 802.11 standard supports two operational modes: The infrastructure-based Wireless Local Area Networks (WLANs) and an infrastructure-less Ad-Hoc Networks. A WLAN (Conti, 2003) typically imposes the existence of an AP and normally is connected to the wired networks to provide internet access for mobile devices. Obviously, only one hop link is needed to communicate between mobile devices and AP. In contrast, there is no AP or infrastructure in Ad-Hoc networks. Any two stations can communicate directly when they are in the range of reception of each other. To this end, the stations may use multi-hop routing to deliver their packets to destinations. The ad-hoc protocols (Conti, 2003; Mohapatra & Krishnamurthy, 2005) are self-configured for address and routing in the face of mobility and the network topology may change in each configuration. The multi-hop wireless ad-hoc networks, or multi-hop wireless networks enable wireless networking in the environments where the wired or cellular connections are impossible, inadequate, or cost effective (e.g. battle field, disaster recovery, etc.). The popularity of internet over the last decades has resulted in rapid advancement of demanding applications. The Transmission Control Protocol/Internet Protocol (TCP/IP) (Stevens, 1994) is a well-known de facto protocol in developing today’s internet. Basically, TCP provides a connection-oriented and reliable end-to-end data delivery between two hosts in traditional wired networks. Since TCP is well tuned and due to its wide acceptance in internet, it is desirable to extend and adopt its functionality to wireless networks. On the

Wireless Local Area Network (WLAN) is an alternative in overcoming cabling problems in a local network. Often wireless network security that is installed still uses vendor default settings such as SSID, IP Address, remote management, DHCP enabled, frequency channels, without encryption, even user or password for wireless administration. How does a strong WLAN security system work? The most common security system applied to wireless networks at this time is starting from securing access points by applying the MAC Filtering concept, using WPA / WPA2-PSK security keys, and RADIUS server authentication. To see the quality of wireless LAN network security, how do you analyze the test of the existing security system in the network. The method that can be used in evaluating wireless networks is by testing the system by simulating forms of attacks on wireless networks with the Penetration Testing method. By carrying out 4 stages of research using the penetration testing method (i) the planning stage, (ii) the discovery stage, (iii) the attack stage and (iv) the report stage, from the attack stage (Cracking The Encryption, Bypassing MAC Address, Attacking The Infrastructure and MITM ) using Kali Linux got the results of four types of attacks carried out, only one of which was failed, namely the cracking attack type of the encryption on the RADIUS server due to using captive portal authentication

Chapter 4 - Multimedia Services over Wireless Metropolitan Area Networks

An egress Network Access Control (NAC) is widely deployed to control users in a wireless network. However, Medium Access Control (MAC) address spoofing is a technique that can easily bypass the egress NAC. So, this vulnerability is a big problem in almost all NAC systems around the world. To solve this problem, we proposeaVisa mechanism to enhance the egress NAC authentication. The mechanism needs only a JAVA applet to run without manually installing any agent-program. To evaluate our new mechanism, we have built a prototyped program, and experiment on a wireless test-bed. The performance evaluation has demonstrated favorable features of our new Visa mechanism.

With the increasing popularity of the wireless network, the security issue for mobile users could be even more serious than it can be expected. Here it is need to search for new architecture and mechanisms to protect the wireless networks and mobile computing application. This paper focuses on intrusion detection and security consideration in wireless local area networks (WLANs) and also presents intrusion detection for WLANs, which gives a wireless intrusion detection system and its architecture consideration. A wireless IDS is similar to a standard, wired IDS, but has additional deployment requirements as well as some unique features specific to WLAN intrusion and misuse detection. Meanwhile, we discuss some issues with wireless networks and Intrusion detection solution to wireless networks.

This dissertation is addressed to novel and high innovative technical solutions for broadband wireless access (BWA) networks.The proposed networks are compatible with the existing IEEE 802.11n wireless local area networks (WLANs), wireless metropolitan area networks (MANs) IEEE 802.16e and WiMAX systems(Worldwide Interoperability for Microwave Access).The proposed designs are linked to the specific requirements which will be incorporated into emerging IEEE 802.16m and LTE advanced (Long Term Evolution) standards.These standards aim at defining an air interface that can ensure high mobility, transmit high data rates and offer higher performance compared to the current standards.The dissertation focuses on advanced radio resource allocation schemes involving cross-layer optimization and hopes to influence these future standards.Radio Resource Management (RRM) algorithms optimize the radio resources especially spectral efficiency and reduce the power consumptions.This work studies mechanisms for downlink (DL) RRM in an environment which suffers from interference created by neighboring transmitters.Beamforming, scheduling and admission control are evaluated.After the description of state-of the-art techniques, advanced algorithms -strategies are developed and simulated.These algorithms take information coming from the radio site (RSSI, CSI, SNR, etc) or from the application layer side (QoS).

OFDM is a multicarrier modulation technique which is used in communication systems like Wireless Personal Area Network (WPAN), Wireless Local Area Network (WLAN), Wireless Metropolitan Area Network (WMAN), Wi-Max, DVB-T etc for the high rate transmission over wireless radio channels. It is commonly known as a transmission technique of high spectral efficiency and robustness against frequency selective fading. The advantages of OFDM include simple digital realization, compatibility with multipath fading channel, less complex receivers and improve the bandwidth efficiency. At the same time, it also increases system capacity providing reliable transmission. But the main problem of OFDM systems is Peak to average power ratio due to its envelope fluctuation. The objective of this project this to provide a broader understanding in peak-to-average power ratio (PAPR) problem in orthogonal frequency division multiplexing (OFDM) systems. This paper showcases main three reduction techniques, precoding and SLM in combination with nonlinear companding in detail considering advantages and disadvantages of each technique.

The development of protocol standards and the low cost of wireless equipment increased the number of wireless network installations in public (airports, universities campuses) and private (enterprises, homes) areas all over the world. This research effort examines the IEEE 802.11 protocol that dominates wireless local area networks (WLANs). Specifically, it investigates the performance of the Distributed Coordination Function (DCF) of ΙEEE 802.11 Medium Access Control (MAC) protocol. The objective of this thesis is to contribute in the research for the development of a simple and effective MAC sub-layer for WLANs that utilize the IEEE 802.11 protocol. Mathematical models are developed to calculate the following metrics in order to examine the performance of DCF that use Binary Exponential Backoff (BEB) algorithm: a) average packet delay per backoff stage and probability per backoff stage b) average packet delay, c) packet jitter, d) packet drop probability, e) average packet drop time, f) packet delay distribution, and g) cumulative packet delay distribution. An admission control algorithm is also presented. The proposed mathematical models are a) simple, as expressed with relatively simple mathematical relations, b) accurate, since they are validated by comparing analytical against simulation results and show that the proposed models are fairly accurate, and c) provide results in short period of time. Different scenarios of WLANs are examined to investigate the effect of DCF parameters in performance and to define the system parameters values that improve the performance of the IEEE 802.11 protocol. The analysis of metrics and the application of their outcomes to WLANs contribute in the design and development of more efficient access methods to wireless medium. The main contribution of this thesis is that packet delay is investigated thoroughly as a measure of WLAN performance.%%%%Η ανάπτυξη προτύπων για τα ασύρματα τοπικά δίκτυα σe συνδυασμό μe το χαμηλό κόστος της ασύρματης τeχνολογίας eπέτρeψe την ραγδαία eξαπλωση των ασυρμάτων δικτύων σe κοινόχρηστους και σe ιδιωτικούς χώρους όπως πανeπιστήμια, πλατeίeς, αeροδρόμια, γραφeία eπιχeιρήσeων, οικίeς, κλπ. Η παρούσα διατριβή μeλeτά το πρωτόκολλο ΙEEE 802.11 το οποίο κυριαρχeί στα ασύρματα τοπικά δίκτυα. Eιδικότeρα eρeυνά την απόδοση της κατανeμημένης διαδικασίας πρόσβασης DCF του υποeπιπέδου MAC του ΙEEE 802.11. Σκοπός της παρούσας eρeυνητικής προσπάθeιας eίναι η συμβολή στην έρeυνα για την ανάπτυξη eνός απλού και αποτeλeσματικού υποeπιπέδου πρόσβασης μέσου MAC στα ασύρματα δίκτυα που βασίζονται στο πρωτόκολλο ΙEEE 802.11. Αναπτύσσονται μαθηματικά μοντέλα για τον υπολογισμό των ακόλουθων μeτρικών για την απόδοση της διαδικασίας DCF που χρησιμοποιeί τον αλγόριθμο eκθeτικής οπισθοχώρησης ΒEΒ: α) την μέση καθυστέρηση των πακέτων ανά βαθμίδα οπισθοχώρησης και την πιθανότητα ανά βαθμίδα οπισθοχώρησης, β) την μέση καθυστέρηση των πακέτων, γ) την κατανομή των καθυστeρήσeων των πακέτων, δ) την αθροιστική κατανομή των καθυστeρήσeων, e) την διακύμανση των καθυστeρήσeων των…