Tuesday, May 5, 2020

Wireless Networks for Complementary Code - myassignmenthelp.com

Question: Discuss about theWireless Networks for Complementary Code Checking. Answer: Physical layer of 802.11b and 802.11a 802.11b: As like any other wireless technology, the IEEE 802.11b standard offers a suitable wireless alternative to wired networks based on a short frequency range application. It is a simple standard that requires a minimal cost to establish. Now, physical layer characteristics (inner workings): 11b operates within the ISM frequency range, a range that encapsulates Industrial Scientific and Medical services. This range is given as 2.4 GHz to 2.4835 GHz. Secondly, it has a convenient chip rate for its radio spectrum interface i.e. 11 MHz which will enable the transmission rate of 1 to 11 Mbps(Geier, 802.11a Physical Layer Revealed, 2003). Furthermore, its frequency band is divided into 14 sections of 22 MHz thickness which diversifies the operational bandwidth. Finally, its operations are supported by several modulation techniques including complementary code checking (CCK) and direct sequence spread spectrum (DSSS). Application of these techniques depends on the data rate being used(Koivisto, 2006). Another suitable alternative to wired systems where wireless communication is supported using the radio spectrum. 802.11a is characterized by the use of OFDM (orthogonal frequency division multiplexing) technique, which increases the bandwidth of transmission. Now, the physical layer: 11a uses the physical layer convergence procedure (PLCP) to convert data frames into the protocol data units (PPDU). This PDU contains fields such preamble, parity value and data rate among others, elements that facilitate communication(Geier, 802.11a Physical Layer Revealed, 2003). Moreover, its functional frequency band is given as 5 GHz, a connection that yields a high data rate of 54 Mbps. It also divides the frequency channel into 48 segments based on the original band of 20 MHz. This diversification of the radio spectrum increases the number of data rates, which enables it to offers various data options i.e. 6, 12 and 24 Mbps. Finally, its modulation is facilitated by different techniques again based on the data rates used. Binary phase shift keying (BPSK)for 6 Mbps and Quadrature amplitude technique (QAM) for 54 Mbps(Khan, 2013). Critical comparison 802.11b 802.11a Data rate 1 to 11 Mbps 6 to 24 Mbps Frequency band 2.4 GHz 5 GHz Modulation techniques CCK and DSSS BPSK and QAM The 802.11i A security protocol developed to solve the problems of the original standard of 802.11 which had various authentication limitations. In general, the 802.11 standards were developed to offer security features of authentication and encryption based on the Wi-Fi protection access (WPA). However, this structure had limitation based on its unencrypted systems, an outcome that exposed WLAN. Now, in its place is the 802.11i standard which provides a second generation security standard (WPA2) having enhanced encryption in the form of AES (Advanced encryption standard). Moreover, a four-way handshake is used based on the extensible authentication protocol (EAP)(Latour, 2012). Client getting server authentication: First, the client request access to the server by sending a notification EAP message. The access port then transmits an EAP message to identify itself. In response, the client encrypts its operations only for the server and authenticator to see. The server gets the messages and requests an identity verification. The client responds, which is either accepted or rejected by the server. If identity is verified, the client is given access to the server by the transformation of the access ports into the authorized state(electronics, 2017). The usage of Virtual Private Networks (VPN) As the name suggests, this technology offers internet subscribers the ability to transmit data using personalized and private channels. These channels are established across the greater medium of the internet where security is never guaranteed. VPNs, encrypt data based on several security protocols including IPsec and GRE (generic routing encapsulation). These protocols facilitate the encryption of data frames which minimizes intrusions based on interception techniques such as snooping and eavesdropping. Moreover, they facilitate the authentication of the access medium through personalized accounts or portals which improves accountability and operation conveniences(Cisco, 2000). Two general types of VPN exist: Site to site networks where big scale connections are established based on verified encryption standards, and Remote access where point to point access is given to users accessing LANs from remote locations. As a multinational organization, ZeeTech is growing at a tremendous rate which has necessitated the need for system expansion. Now, Wireless Metropolitan Area Network offers a convenient solution for this business as it would facilitate the exchange of information across a wider area while meeting the conveniences of wireless transmission. Several WMAN technologies are thus considered: WiMAX: using the 802.16 standards, WiMAX is outlined as the best alternative for meeting the WMAN connection requirement. This conclusion is based on the resources and services it offers including a wide coverage area as well as a high data rate (Omerovic). In all, this technology is characterized by the following features as related to ZeeTech applications: First, it establishes connections that facilitate the operation of first and last mile system which will boost services across the Melbourne branches. Secondly, it has a wide frequency band (10 GHz and 66 GHz) which increases the bandwidth of operation. It also stems down its functionalities to include low-frequency operations i.e. 11 GHz band range. Furthermore, its characterized by a high data rate of between 100 Mbit/s to 1 g Gbit/s. Its security features include high-level air interface encryption and authentication which enables end to end encryption. Finally, the cost is based on user requirements which increase the service quota(IEEE, 2016). HiperACCESS: another common WMAN technology that facilitates the implementation of broadband services across a medium-sized system. Now, while this technology may have a few limitations, it does offer backhaul services that include mobile technology solutions such as GSM. In all, it has the following features in relation to the case study: A relatively high data rate of 100Mbit/s Secondly, it does have a high-frequency band 40.5 GHz which also happens to limit low-frequency functionalities. This frequency range increases the coverage area, but it also affects the low-frequency systems as they are never supported. Advanced access control is used for security purposes. Finally, has a minimal implementation cost(WMICH, 2015). HiperMAN: The final alternative for WMAN networks, HiperMAN offers broadband connections based on a 2 GHz frequency band. It is also characterized by: Optimal transfer rates that reach up to 56.9 Mbit/s. A frequency band that facilitates low-frequency data transmission (below 11 GHz). Improved point to multipoint configuration, an outcome that facilitates the application of mesh networks. High-end encryption boosted by optimal modulation techniques. A low-cost solution(ETSI, 2009). 2G technologies Time division multiple access (TDMA) a multiplexing technique that is used in wireless communication to optimize the bandwidth of data transmission. The TDMA technique uses a time scheme to allocate space across the radio spectrum(point, 2017). In essence, the frequency band is split into several slots that are assigned to users based on a time allocation procedure. Features: Optimal for both data and voice transmission. Allocates radio spectrum space based on time. A cheap solution for analog to digital transmission. Code division multiple access (CDMA) another multiplexing technique that is used in wireless networks to maximize the bandwidth of operation. Unlike TDMA, CDMA does not allocate the space of the radio spectrum, instead, it facilitates transmission of several signals by using a pseudo-code identification scheme. Therefore, unique codes are assigned to the individual users who use the entire radio spectrum. Now, this outcome increases the individual bandwidth of the communicating signals which is a convenient solution for modern digital systems. Features: Offers an extended bandwidth of operation. High-end security features based on pseudo code encryption. Finally, optimal for both data and voice transmissions. Global system for mobile communications (GSM) another wireless technology that offers both digital and cellular functionalities. GSM is identified as an open technology as its function objectives promote integration and interoperability(FLETC, 2012). Furthermore, unlike the previous two, it uses circuit switching techniques to establish network connections. Features: A circuit-switched technology. Transmits both data and voice. References Cisco. (2000). Introduction to VPNs. Extending the Classic WAN, Retrieved 27 September, 2017, from: https://www.cisco.com/networkers/nw00/pres/2400.pdf. electronics, R. (2017). IEEE 802.11i Wi-Fi Security: WEP WPA / WPA2. Radio electronics, Retrieved 27 September, 2017, from:" https://www.radio-electronics.com/info/wireless/wi-fi/ieee-802-11i-security-wpa2-wep.php. ETSI. (2009). Broadband Radio Access Networks (BRAN); HIPERACCESS; Packet based Convergence Layer; Part 1. ETSI TS 102 117-1, REtrieved 27 September, 2017, from: www.etsi.org/deliver/etsi_ts/102100_102199/.../01.01.../ts_10211502v010101p.pdf. FLETC, D. . (2012). Global System for Mobile Communication Technology. Mobile Device Investigations Program, Retrieved 28 September, 2017, from: https://www.eff.org/files/filenode/global_system_for_mobile_communication_technology.pdf. Geier, J. (2003). 802.11a Physical Layer Revealed. Wi-Fi planet, Retrieved 26 Sepember, 2017, from:www.wi-fiplanet.com/tutorials/article.php/2109881/80211a-Physical-Layer-gra.htm. IEEE. (2016). The IEEE 802.16 Working Group on Broadband Wireless Access Standards. WirelessMAN standards for Wireless Metropolitan Area Networks, Retrieved 26 September, 2017, from: https://www.ieee802.org/16/. Khan, R. (2013). Comparison of IEEE 802.11a, IEEE 802.11b and IEEE 802.11g. Code project, Retrieved 27 September, 2017, from: https://www.codeproject.com/Articles/13253/Comparison-of-IEEE-a-IEEE-b-and-IEEE. Koivisto, T. (2006). Overview of IEEE 802.11b Wireless LAN. S-72.4210 Postgraduate course in Radio Communication, Retrieved 26 September, 2017, from: https://www.comlab.hut.fi/opetus/4210/presentations/8_wlan.pdf. Latour, L. (2012). 802.11i, Authentication and You. CISCO, Retrieved 26 September, 2017, from; https://supportforums.cisco.com/t5/wireless-mobility-blogs/802-11i-authentication-and-you/ba-p/3104143. Omerovic, S. (n.d.). WiMax Overview. Retrieved 27 September, 2017, from: https://www.lait.fe.uni-lj.si/Seminarji/s_omerovic.pdf. WMICH. (2015). WPAN, WLAN, WMAN. Retrieved 26 September, 2017, from; ttps://cs.wmich.edu/alfuqaha/Fall11/cs6570/lectures/Bluetooth-ZigBee.pdf.

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