WiMAX Filters at Different Frequency Spectrums

Transcription

1 Advance in Electronic and Electric Engineering. ISSN , Volume 4, Number 1 (2014), pp Research India Publications WiMAX Filters at Different Frequency Spectrums Akash Srivastava and Sakshee Srivastava Mtech-final year, Communication Engineering, Galgotias University, 2Yamuna Expressway, Sector 17A, Greater Noida, UP Mtech-first year, Communication Engineering, Galgotias University. 2Yamuna Expressway, Sector 17A, Greater Noida, UP akash2011srivastav@gmail.com, engg.sakshee@gmail.com Abstract Wimax gives solution to the problems regarding coverage area using different filters operating at different allocated frequency spectrum. Providing variety of options to increase mobility long distance communication and direct access to internet. This paper presents wimax with different filters at transmitter and receiver ends. Keywords: Introduction, filters used in wimax at different frequency spectrums, conclusions, references. 1. Introduction WiMAX is short for Worldwide Interoperability for Microwave Access, and it also goes by the IEEE name WiMAX has the potential to do to broadband Internet access what cell phones have done to phone access. In the same way that many people have given up their "land lines" in favor of cell phones, WiMAX could replace cable and DSL services, providing universal Internet access just about anywhere you go. WiMAX will also be as painless as WiFi turning your computer on will automatically connect you to the closest available WiMAX antenna. It is a wireless communications standard designed to provide 30 to 40 megabit-per-second data rates, with the 2011 update providing up to 1 Gbit/s for fixed stations. 1.1 The IEEE Standards Standards Used In Wimax IEEE (IEEE d)

2 16 Akash Srivastava & Sakshee Srivastava The IEEE a standard is actually a mere added and revised version of IEEE IEEE defines details specifically to the physical layer and the MAC layer of the 2-66G frequency range. IEEE (IEEE e) IEEE e standard version based on the IEEE standard, aiming to propose a wireless\ broadband solution providing high-speed information transmission and supporting highspeed moving. Just because IEEE e supports the high-speed information transmission in moving, it is considered the sole wireless broadband technology of the next generation competitive to 3G. 1.3 Structure of WiMAX Network System The WiMax network system mainly comprises of core network and access network. The core network includes the network management system, router, AAA agency or server, user database, and Intern gateway equipment. It mainly provides an IP connection to WiMax users. The access network includes base station (BS), subscriber station (SS) and mobile subscriber station (MS). It mainly provides wireless access to WiMax users. Fig : IP-Based WiMax Network Architecture and mesh structure Core Network The WiMax core network is mainly responsible for the user authentication, roaming service, network administration and providing interface to other networks. Its network administration system is used to monitor and control all base stations and subscriber stations in the network, and provide the functions of inquiry, condition monitoring, software download, and system parameters configuration. The IP network connected to the WiMax system is generally a traditional switching network or the Internet or other networks Access Network The base station provides a connection between the subscriber station and the core network. It generally uses a sector/beam antenna or umbrella antenna, which provides flexible arrangement and configuration of sub-channels, upgrades and expands the network based on the conditions of users. The subscriber station is a kind of base station, which provides the repeater connection between the base station and the

3 WiMAX Filters at Different Frequency Spectrums 17 equipment of user terminal. It generally uses a beam antenna installed on the roof. The dynamic adaptive modulation mode of the signal is used between base station and subscriber station Base Station The base station provides a connection between the subscriber station and the core network. It generally uses a sector/beam antenna or umbrella antenna, which provides flexible arrangement and configuration of sub-channels, upgrades and expands the network based on the conditions of users User Terminal Equipment The WiMAX system defines the connection interface between the user terminal equipment and the base station, and provides the access of terminal equipment. However, the user terminal equipment does not belong to the WiMAX system. 2. Filters Used in WiMAX at Different Frequency Spectrums 2.1 Block diagram of WiMAX In the given block diagram the serial data input is mapped to fast fourier transform (FFT) bins that are assigned and an inverse FFT (IFFT) process is carried on as a modulation method. A cyclic prefix is inserted to mitigate multi-path fading and inter symbol interference, sacrificing an increase in bandwidth. At the final stage, there is an RF band pass process, which shifts baseband signals to a carrier frequency. At the receiver side, a reverse process is performed to extract actual original data. Fig. 2.1: Block Diagram Of Wimax At Transmitter And Receiver Ends. 2.2 Frequency spectrums in WiMAX The WiMAX Forum currently supports continued rapid WiMAX user adoption in the 2.3 GHz, 2.5 GHz, and 3.5 GHz frequency bands, with additional spectrum bands to come. As can be seen filters play a very important role in WiMAX for reception and

4 18 Akash Srivastava & Sakshee Srivastava transmission purposes. The RF bandpass filters used in the block diagram can be designed in many ways at given various frequency spectrums. 1. Compact narrowband bandpass filter using dual mode octagonal meandered loop resonator used for WiMAX- This new model of filter is also useful for WLAN and mobile communication application since,its compact in size low loss and low cost with good performance of elliptical response with sharp rejection and adequate fractional bandwidth.wimax, local multipoint distribution service(lmds) etc require an increase in capacity by reducing the coverage area. The various technologies which are using to obtain this objective is based on radio aver fiber(rof).where signal processing is carried out at a central office to where signals are carried from inexpensive remote antenna units.(raus). Fig. 2.1: Compact narrowband bandpass filter using dual mode octagonal meandered loop resonator and its response. 2. Multiband microwave filter for wireless communication- The open loop ring resonator filters,which are comprised of two uniform microstrip lines and pairs of open loop between them for this purpose. These are generally multiband micostrip filters and based on differential evalution(de) with strategy adaption. This algo is population based stochastic global optimization algo which has been used in several real world engineering problems like fuzzy logic,controller design problem, molecular sequence alignment problem and automatic image pixel clustering. The first filter designed for two wimax(ieee ) frequency bands,these are 3.5 ghz and 5.8 ghz frequency bands.after that the triband filter was designed for operation in two WiMAX(802.16) and one WiFi frequency bands,these are 2.4 ghz,3.5 ghz and 5.8 freqency bands.

5 WiMAX Filters at Different Frequency Spectrums 19 Fig. 2.2: Multiband microwave filter and its response. 3. Low profile LTCC balanced filter based on lumped elements balun for wimax applications- This method based on a new lumped LC type balun. The balanced filter is realized as combination of second order band pass filter and the novel LC balun with an additional low pass circuit and the proposed layout realized using multilayer low temperature cofired ceramic (LTCC ) technology. The resulting structure exhibits electrical performance,immunity to manufacturing tolerance and compactness. These filters placed between two ground planes ensure high electromagnetic compatibility and this filter make a building block of highly integrated WiMAX front and modules. Fig. 2.3: Low profile LTCC balanced filter based on lumped elements balun and its response. 3. Conclusion Wimax gives better solution to mobile as well as fixed communication with its QOS at MAC layer. Based on microwaves it provides long distance communication in non line of sight. It can be implemented more easily and efficiently using different filters at different frequency spectrums allocated to WiMAX. These filters increases its

6 20 Akash Srivastava & Sakshee Srivastava advantage of long distance error free transmission as we know antennae and filters are two basic requirements and strength of any communication. Incorporated with these variety of choices WiMax promises to deliver the Internet throughout the globe, and connect the "last mile"of broadband wireless connectivity services. Representing the development orientation of wireless communication technology, the technique becomes the recognized key technology for mobile communication system in the future. It is not only applicable for WiMax system, but also the kernel of the 4G system. For its excellent performance, WiMax rises from a high base, and used to be considered as the most powerful competitor of mainstream mobile communication standards. References [1] Microwave Filters, Impedance-matching Networks and Coupling Structures, Artech House, Norwood, MA O.A.R. Ibrahim, A. Halim GHz microstrip bandpass filter for ISM band, Applied Electromagnetics, 2007 Asia-Pacific Conf. on, J.C. Rautio, Experimental Validation of Electromagnetic Software, International Journal of Microwave & Millimeter Wave CAE, Vol. 1, No. 4, Oct. 1991, pp [2] M. Kirschning, and R.H. Jansen, Accurate wide-range design equations for parallel coupled microstrip lines, R..Mongia, P. Bhartia and I.J.Bahl, RF and Microwave Coupled-line Circuits, 2nd ed., Artech House, Boston, M. Kirschning, R.H. Jansen, and N.H.L. Koster, Accurate model for open end effect of microstrip lines, Electronics Letters, 17, Feb. 1981, pp [3] J.S. Hong, and M.J. Lancaster, Microstrip Fitlers for RF/Microwave Applications, Wiley,New York, J. G. Andrews, A. Ghosh, R. Muhamed, Fundamentals of WiMAX Understanding Broadband Wireless Networking, Prentice Hall, 2007.G. Savo Advanced Wireless Networks 4G Technologies, University of Oulu,2006.Wireless Technologies-Overview and History.