Discuss About The Global System For The Mobile Communications?
First and foremost, this standard uses the orthogonal frequency division multiplexing technique to facilitate its operations, which includes a data rate of 54Mbps and a frequency band of 5GHz. The standard also defines the operations of WLAN having several improvements as compared to the original standard. Below are its physical layer attributes as compared to 802.11b:
- First, OFDM is used which is not a spread spectrum multiplexing technique(Geier, 802.11a Physical Layer Revealed, 2003).
- OFDM divides the communication signal into 48 different subsections across a 20MHz channels.
- It has a data rate of 6, 12 and 24 Mbps
- Furthermore, it uses different modulation techniques depending on the data rate e.g. the binary phase shift keying for 6Mbps and quadrature amplitude modulation for 54 Mbps(Geier, 802.11a Physical Layer Revealed, 2003).
Data rates of 6, 12 and 24 Mbps
Based on the chip rates; 1, 2, 5.5 and 11 Mbps data rates
Different modulation techniques are used; BPSK and QAM.
Spread spectrum and complementary code key
802.11i is an advancement of the original 802.11 standard that addresses the security shortcomings of WPA. Its authentication process incorporates WPA with WPA2 and AES encryption. Moreover, it introduces the structures of robust security network where a four-way handshake is used with a group key handshake. Furthermore, the extensible authentication protocol (EAP) is used as the defining protocol for the standard. This outline defines the authentication of a client to a server(Latour, 2012).
In all, the authentication process involves three elements supplicant (device requiring authentication, client), the authentication server and authenticator (relay agent).
- The client sends an EAP start notification message.
- Secondly, the access point then sends an EAP request message to identify itself.
- Client EAP response is followed as it is ‘proxied’ to both authenticator and the server.
- Thereafter, the server challenges the identity of the client and so does the client which checks the server’s credentials.
- Server accepts or reject client request for a connection.
- If accepted the virtual port is changed to authorized state and at the end, its changed back to unauthorized state(Latour, 2012).
Now, during the encryption process, a set of keys are used to authenticate the users and they can be either symmetrical keys (shared) or public keys (public-private). Moreover, the encryption is supported by various protocols including IPsec and GRE (generic routing encapsulation. In all this encryption facilitates safe transmission of data across public mediums which improves their efficiency and convenience.
WMAN (Wireless Metropolitan Area Network) technologies
WMAN allows users to establish wireless networks across different locations at minimal costs as they do not need to implement the physical infrastructures of wired networks such as fibre and copper cabling. Furthermore, the technology does also serve as a backup to wired connections in case they fail during operations. In terms of operation, WMAN uses either infrared lights or radio waves to propagate information (UOM, 2005).
In this case, we analyze three different standards for the case study at hand where 40 employees are considered while having 400 daily customer services and at the end, the 802.16 standards are chosen as the best choice. The three standards are:
- 16 wireless MAN standard.
HiperACCESS: an interoperable technology that provides broadband connections to medium-sized enterprises. Moreover, the technology also offers backhaul services for mobile systems needed by businesses such as GSM and GPRS. It’s also a convenient substitute for wired broadband connections as it offers high data rates of about 100 Mbit/sec. Furthermore, its target frequency band ranges between 40.5 GHz and 43.5 GHz which offers a wider service area. In terms of the cost, the technology does offer a convenient compromise to wired structure although additional techniques and resources are needed for low-frequency operations (WMICH, 2015).
HiperMAN: a standard that is designed to offer broadband wireless access while operating within the radio frequencies of 2 and 11 GHz which boost its operations for low laying frequencies. Moreover, it operates with almost the same data rate as the HiperACCESS technology however, its practical application can only extend as much as 25 Mbit/sec. Nevertheless, its services are optimized by point to multipoint configurations (PMP) which improves its air interface, an outcome that facilitates mesh network applications. Furthermore, its cost is radically reduced because it does not require any additional features to meet its QoS quota or any other system metrics (works, 2017).
Chosen technology for the case study
802.16: Defined as an industrial standard, the IEEE 802.16 standard was created in 2002 to offer the conveniences of metropolitan connection under wireless networks. Its application addresses both the requirements of last and first-mile connection having an effective bandwidth of either 10 GHz or 66 GHz. Moreover, it supplements its functionalities by incorporating the needs for low-frequency operation where bands ranging between 2 and 11 GHz are supported. Furthermore, it defines an innovative medium access control (MAC) layer that supports various physical layers that can be customized to fit the frequency needs of the users (IEEE, 2016). In terms of the data rate, the 802.16 standard offers extensive data rate ranging from 100 Mbit/sec to 1 Gbit/s. This outcome increases its service area beyond that of the other WMAN technologies. In addition to this, this technology offers the best cost to functionality ratio having the best data rate, speeds and channels for communication, a convenient solution for the case study at hand.
Multiple access technologies
Time division multiple access (TDMA): a transmission technique that maximizes the bandwidth of wireless communication by allocating different signals channels based on a timing schematic. In essence, a single communication channel (frequency) will be split between two different users using time slots. Furthermore, each cellular slot is divided into three division which increases the bandwidth and therefore the data transferred (point, 2017).
Abilities and features:
- Transmits data and voice.
- Carries content of between 64 kbps and 120 Mbps data rate.
- It's based on time.
- Extends battery life as it based on the immediate needs of the user.
- Cost effective for analogue to digital conversion.
Code division multiple access (CDMA): another wireless communication technique that maximizes the bandwidth of transmission. It carries out its functionalities based on the spread spectrum technique where resources diverge over a wide area. Moreover, unlike other multiplexing techniques, it does not assign frequency slots which enables all signals to use the entire bandwidth during transmission. Nevertheless, CDMA uses pseudopods to encode data and to distinguish it during transmission (point, 2017). This outcome increases the capacity of transmission which is suitable for modern mobile systems.
Abilities and features:
- Uses pseudo codes without any form of allocation.
- Suitable for both data and voice transmission.
- It has very large capacities for data transmission.
Global system for mobile communications (GSM): A digital and cellular technology that is used to transmit information via wireless systems. Moreover, GSM is defined as an open technology that is used to transmit both voice and data across mobile systems. This technology greatly differs from first-generation mobile technologies such as TDMA as it’s a circuit switched technology which means it requires to establish a connection before transmission. Furthermore, it also divides the 200 kHz communication channel into 8 different 25 kHz slots. Finally, its operations range between the 900 MHz and 1.9GHz band range across the globe (Education, 2012).
Abilities and features:
- Transmits both data and voice.
- Circuit-switched technology.
- Wider band range
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