iosr-JECE   Volume-1 ~ Issue-4

Abstract : 4G is a brand name for the Fourth Generation of the cellular wireless standards. Over the years, Nigerian telecommunication firms have been in operation with predecessor generation standards (such as 2G and 3G). The design principle of each of these cellular wireless standards follow the same principle, where the information to be transmitted will pass from transmitter through a channel to the receiver at a frequency within the allowable band. For a long distance transmission to take place, information to be transmitted need to be modulated with high frequency also known as carrier frequency. This implies that for any licensed telecom firm in Nigeria, a carrier frequency slot from the regulatory body must be allotted. This research work aims to study the practice of telecommunications in Nigeria vis-à-vis the latest 4G technology around the world; identify the existing technologies in Nigeria; identify the limitations of Telecommunication Service Providers (TSPs) in Nigeria that may be responsible for delay (if any) in migration to 4G technology. The research methodology that was adopted in this research is the survey, interview, questionnaires and the use of statistical analysis tool (SPSS).
Keywords: Telecommunication, Communication, Fourth Generation (4G), Transmission

[1] Adegboyega D. (2008). Tell Magazine. Seven Years of Telecoms Revolution-Telecommunication is an Expensive Project. 16-17.
[2] Ademilola B. (2007). Tell Magazine. The Telecoms Revolution-NCC, its Mandate, its Vision. 5.
[3] Ademola O. (2008). Tell Magazine. Seven Years of Telecoms Revolution. 16-17
[4] Ajayi G.O, Salawu R.I, Raji T.I (2011). A century of Telecommunication Development in Nigeria- What next. Oxford Scholarship Online, 163.
[5] Ajibose O. (2006). Performance Evaluation of Fixed Cellular telecommunication Networks using Java. (Unpublished master's thesis). University of Ibadan, Nigeria.
[6] Ajiboye O., Adu O., Wojuade I. (2007). The Impact of GSM on Nigeria Rural Economy:
[7] Implication for an Emerging Communication Industry. Journal of Information Technology Impact, Vol.7 (2), 131-144.
[8] Akuamoa W. (2007). Telecommunication Development in Africa- Ghana has come a long way. Retrieved on August 21,2011 from http://www.modernghana.com/news/132898/1/telecom-development-in-africaghana-has-come-a-long.html.
[9] Alabi G.A. (1996). "Telecommunications in Nigeria", Retrieved on September 12, 2011. From http://www.africa.upenn.edu/ECA/aisi_inftl.html.
[10] Arzika M.(2000). National Policy on Telecommunications Retrieved on October 21, 2011 from http://www.researchictafrica.net/countries/nigeria/NationalPolicy on Telecommunication.pdf.
[11] Behrouz A. F. (2006). Data Communication and networking. India: McGraw-Hill Education India Pvt Ltd.
[12] Bernard S. (2003). Digital Communication- Fundamentals and Applications. New Jersey: Library of Congress.
[13] Bruce C. (1975). Communication Systems an Introduction to signals and noise in electrical communication. United States of America: McGraw-Hill.
[14] Carlson, Crilly, Rutledge (2002). Communication Systems- An Introduction to Signals and Noise in Electrical Communication. (4th edition). New York: McGraw- Hill.
[15] Edwin W and Deon R .(2004). Telecommunication and Wireless Communication for Bussiness and Industry. (1st edition). Burlington: IDC technologies.

ABTRACTS : Wide bandgap, high saturation velocity, and high thermal stability are some of the properties of GaN, which make it an excellent material for high-power, high-frequency, and high-temperature applications. As several application areas require the devices to operate at elevated power range, a proper modeling of the device using the property of band structure and transport parameters is very important.Progress on materials development includes the development of AlGaN and AlN barrier HEMTs with room temperature electron mobility nearly 2000 cm2/ V-s. Trap free GaN HEMT devices over12 W/mm power density and device operating at frequencies nearly to 300 GHz are presented. We present two-dimensional simulations of AlGaN/GaN high electron mobility transistors (HEMTs) at high frequencies are carried out with Silvaco ATLAS tool. The 2DEG dependence of the maximum current and cut-off frequency of submicron devices is further studied.
KEYWORDS : HEMT, 2DEG, ATLAS, Heterostructure, Nucleation Layer

[1] Arulkumaran S, Egawa T, Ishikawa H, Jimbo T. High-temperature effects of AlGaN/GaN high-electron-mobility transistors on sapphire and semiinsulating SiC substrates. Appl Phys Lett 2002;80(12):2186–8.
[2] Arulkumaran S, Liu Z, Ng G, Cheong W, Zeng R, Bu J, et al. Temperature dependent microwave performance of AlGaN/GaN high-electron-mobility transistors on high-resistivity silicon substrate. Thin Solid Films 2007;515(10):4517–21.
[3] Vurgaftman I, Meyer J, Ram-Mohan L. Band parameters for III–V compound semiconductors and their alloys. J Appl Phys 2001;89(11):5815–75.
[4] Guo Q, Yoshida A. Temperature dependence of band gap change in InN and AlN. Jpn J Appl Phys 1994;33(5A):2453–6.
[5] Yoshida S, Misawa S, Gonda S. Properties of AlxGa1_xN films prepared by reactive molecular beam epitaxy. J Appl Phys 1982;53(10):6844–8.
[6] Shan W, Ager J, Yu K, Walukiewicz W, Haller E, Martin M, et al. Dependence of the fundamental band gap of AlxGa1_xN on alloy composition and pressure. J Appl Phys 1999;85(12):8505–7.
[7] Westmeyer A, Mahajan S, Bajaj K, Lin J, Jiang H, Koleske D, et al. Determination of energy-band offsets between GaN and AlN using excitonic luminescence transition in AlGaN alloys. J Appl Phys 2006;99(1):013705(4).
[8] Ambacher O, Foutz B, Smart J, Shealy J, Weimann N, Chu K, et al. Twodimensional electron gases induced by spontaneous and piezoelectric polarization in undoped and doped AlGaN/GaN heterostructures. J Appl Phys 2000;87:334–44.
[9] M.C.J.C.M. Krämer, R.C.P. Hoskens, B. Jacobs, J.J.M. Kwaspen, E.M. Suijker, A.P. de Hek, F. Karouta, and L.M.F. Kaufmann, "Dispersion free doped and undoped AlGaN/GaN HEMTs on sapphire and SiC substrates," Proc. Gallium Arsenide and other Compound Semiconductors Application Symposium 2004 (GAAS 2004), p75, 11 - 15 October 2004, Amsterdam, The Netherlands.
[10] Y. Ando, Y. Okamoto, K. Hataya, T. Nakayama, H. Miyamoto, T. Inoue, and M. Kuzuhara, "12 W/mm recessed-gate AlGaN/GaN heterojunction field-plate FET," Proc. IEEE International Electron Devices Meeting. IEEE, p 563, 2003.

ABSTRACT: This work implements a software based SMS switching system using GLOBACOM and MTN as network carriers. JAVA programming language with focus on socket programming will be used for the software development. The application client, which is the portion that runs on the mobile phone, uses Java macro Edition, while the server section involved in the switching uses Java Servlet. When tested on the windows 7 operating system using oracle and the SUN mobile phone simulators, there was quick response and transmission of the SMS text from one end to the other. The application was similarly simulated on the UNIX based operating system such as Linux, and Solaris. There was high level of success on the simulation showing that the results are reliable. However the results could only handle up to 100 characters per SMS and a 64 bit encryption technique was used. Keywords: gateway; IP; Java; module; SMS

[1] Hillebrand, Trosby, Holley, Harris (2010) SMS the creation of Personal Global Text Messaging, Wiley
[2] Tomasi, Wayne (2004) Introduction to Data Communications and Networking, 1st ed. Upper Saddle River, NJ: Prentice Hall.
[3] Gil Held (2001) "Data over Wireless Networks". Wiley, NJ
[4] Gredle Rose (2005) GSM standards and services publication of IEEE, 2005
[5] Rheingold Victor (2002). Mobile Computing Handbook. Artech House Mobile Communications Library. Artech House..
[6] Sun Microsystems (2009), Java 2 Platform, Micro Edition (J2METM Platform).Available as http://java.sun.com/j2me/
[7] Shannon Hills (2007) Introduction to Mobile Computation, 3rd ed., NJ: Prentice Hill