Conceptual Models and Design Methodology †Free Samples to Students

Question: Discuss about the Conceptual Models and Design Methodology. Answer: Introduction: The Wireless Local Area Networks or WLANs with higher speed are extremely popular in all sectors of the world (Vinel, 2012). These sectors are the most important sectors for any society. The main standard for the WLANs is the IEEE 802.11. The specification of this 802.11 standard is that it specifies the physical layer and the MAC or medium access control for the WLANs. For the physical layer of the WLANs, this particular standard has four typical standards. They are the 802.11a, 802.11b, 802.11g and 802.11n (Bayraktaroglu et al., 2013). The comparison and contrast between 802.11a and 802.11b are as follows: Key Aspects 802.11a 802.11b 1. Range of Frequency Up to 5 GHz Up to 2.4 GHz 2. Speed or Rate in Mbps 6, 9, 12, 18, 24, 36, 48, 54 1, 2, 5.5, 6, 9, 11, 12, 18, 22, 24, 33, 36, 48, 54 3. Modulation Binary Phase Shift Keying, Quadrature Phase Shift Keying, 16 Quadrature Amplitude Modulation 64 Quadrature Amplitude Modulation (Orthogonal Frequency Division Multiplexing) Differential Phase Shift Keying, Differentially Quadrature Phase Shift Keying, CCK (Direct Sequence Spread Spectrum, FH and IR) 4. FEC Rate 1/2, 2/3, 3/4 NA 5. Base Rate Up to 6 Mbps Up to 1 or 2 Mbps 6. Functions Providing eight PHY modes and transmitting data (Naraei, Amiri Saberi, 2014). Serves as the interface between physical layer and host device and the robustness features are Packer Fragmentation and Cyclic Redundancy Check or CRC. The above table clearly defines about the comparisons and contrasts between the two typical standards of 802.11, which are the 802.11a and 802.11b. Both of them work in the physical layer. The 802.11i standard enhances the 802.11 with various innovative mechanisms of security for ensuring the integrity and confidentiality of messages (Alasmary Zhuang, 2012). Some of the new mechanisms are the additions, and others are the absolute replacements of the procedures of 802.11. 802.11i also allows any other standard of IEEE which is the 802.1x port authentication algorithm, for providing a specific framework to obtain a strong management of keys and mutual authentication (De Cristofaro et al., 2013). The authentication procedure that starts at first is normally carried out by following two distinct ways. One way is to utilize the Pre-Shared Key or PSK and the second way is to follow the exchange of EAP via 802.1x. This EAP exchange is called as the EAPOL. The authentication server is needed or required to be present during the following of EAP exchange (Vinel, 2012). The procedure of EAP exchange makes sure that client device or the client station is to be authenticated wit h the help of an access point. Once the pre shared key or the authentication of 802.1x is completed, a new shred secret key is created (Naraei, Amiri Saberi, 2014). This is known as the PMK or pair wise master key. Thus, the 802.11i allows for a client device to be authenticated against an authentication server with the help of the EAP exchange. A VPN or a virtual private network is nothing but an extension of a private network that allows its users to transmit any type of data or information in public networks with utmost security (Uskov, 2012). The applications that are run on a virtual private network get all the advantages from the security, functionality and management of the network. This VPN works just like the several devices of computing connected directly. This private network is normally created with the help of an establishment of a typical point to point connection virtually by dedicated connections and of course by certain traffic encryption. The encryption algorithm helps the communication to be safe and secured from any type of intrusion in a point to point communications on a public network (Uskov, 2012). The main advantage that VPN provides to the point to point connection on a public network is that it acts like a wide area network or WAN. ZeeTechis a multinational company of export and import. There are five offices with forty employees in each office. Around four hundred daily clients or customers are attended daily by these offices (Naraei, Amiri Saberi, 2014). They have thought of implementing a Wireless Metropolitan Area Network or WMAN technology in their company, which will link all the five offices and moreover, will provide a mobile wireless access to the field workers as they have to travel in various sites. ZeeTech has thought of implementing one Wireless Metropolitan Area Network in each of its five offices. There are few technologies of WMAN (Vinel, 2012). The best technology should be implemented in ZeeTech for their business amongst all the other technologies. There are three types of standards for WMANS. They are the HiperMAN, HiperACCESS and IEEE 802.16. The HiperMAN or the High Performance Radio Metropolitan Area Network is the technology that provides a solution for broadband wireless for any Metropolitan Area Networks (Wang, Zhu Gomes, 2012). HIPERMAN normally operates between the radio frequency range of 2 GHz and 11 GHz. The main advantage of this technology is that it enables flexible mesh network deployments. The HiperACCESS or the High Performance Radio Access is the technology that provides broadband access to small and medium sized enterprises. It even provides backhaul for the mobile systems like WCDMA, GSM, CDMA2000 and GPRS (Wang, Zhu Gomes, 2012). This particular technology was developed for providing a broadband system with but rates that ranges up to 100Mbit/sec approximately. However, the most widely deployed rate is about 25Mbit/sec. It is mainly developed for the higher frequency bands like the 40,5 to 43,5 GHz band. The IEEE 802.16 Wireless MAN technology mainly specifies the air interface for these networks. This technology follows the connection of first mile/last mile in the WMANs (Bayraktaroglu et al., 2013). It mainly aims at the significant utilization of bandwidth between 10 to 66 GHz and further helps to define a MAC layer, supporting the various physical layer specifications. The HiperACCESS technology of WMAN would be the best technology for ZeeTech. This provides a greater speed and also mobile communication (De Cristofaro et al., 2013). Moreover, it provides Backhaul, which means it helps in cellular tower connection, enterprise networks and Wi-Fi connections. It is cost effective and ZeeTech can easily afford it. Conclusion Therefore, from the above discussion it can be concluded that ZeeTech is a multinational company that deals with export and import business. This particular company has five offices in Melbourne. All the offices have about forty employees working and around four hundred customers or clients are attended regularly in these five offices. ZeeTech has decided to implement a Wireless Metropolitan Area Network or WMAN technology in all of their five offices. This will help in linking up the networks of all the five offices and also will provide a mobile wireless access for the workers who travel regularly to various sites across the city for their jobs. ZeeTech should select HiperACCESS technology for their WMAN implementation. Discuss the three different multiple access technologies used with 2G: time division multiple access (TDMA), code division multiple access (CDMA), and global system for mobile communications (GSM). The main three multiple access technologies that are utilized with 2G are the Time Division Multiple Access or TDMA, Code Division Multiple Access or CDMA and the Global System for Mobile Communications or GSM. The description is given below: i) TDMA: The Time Division Multiple Access is a procedure of accessing the channel for all types of networks that are shared medium. TDMA enables all the users in sharing the similar frequency channel (Ma, Leung Li, 2014). This sharing is done by segmenting a specific signal into various slots of time. The transmission is done rapidly by the users. This particular technology is utilized with 2G. ii) CDMA: The Code Division Multiple Access or CDMA is the procedure of accessing the channel, similar to TDMA. However the difference between two is that CDMA is utilized by several technologies of radio communications (Glisic Leppnen, 2013). The data or the information can be transmitted by several transmitters in a single channel of communication simultaneously. For this particular reason, various users can share frequencies. This particular technology is also utilized with 2G. GSM: The Global System for Mobile Communication or GSM is the mobile system of telephony that works digitally (De Cristofaro et al., 2013). This particular communication utilizes the various TDMA technologies within it. 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