Performance Analysis of GSM Network for Different Types of Antennas

Int. Journal of Electrical & Electronics Engg.

Vol. 2, Spl. Issue 1 (2015)

e-ISSN: 1694-2310 | p-ISSN: 1694-2426

Performance Analysis of GSM Network for Different Types of Antennas Mandeep Singh, Supreet kaur Department of ECE, Punjabi University, Patiala, India

Abstract: Today, in metro cities BTSs are increasing day by day and interference is also increasing. This paper shows the received power of the cell depends on a number of factors.

Antenna gain and antenna type are one of the important parameters for this. This paper reveals the effect of signal received power by changing the antenna gain and antenna type.The antenna used is omnidirectional and switched beam and gain varies from 5 to 15 dB.The GSM network is simulated for 6 users in Qualnet software.

Keyword:Antenna gain, GSM, omnidirectional antenna, switched beam antenna, Qualnet Software.

I. INTRODUCTION The GSM system for mobile communications is a digital cellular communication system. The GSM is the most widely used technology used in the world today. During the early 1980s, analog cellular telephone system experienced a very rapid growth in Europe. GSM system is based on the digital technology, which has many advantages over analog technology. It also provides the technology as roaming, SMS, fax mail.

Table 1. GSM specifications Multiple access technology

FDMA/TDMA

Duplex technique Uplink frequency band Downlink frequency band

FDD 890-915 MHz 935-960 MHz

Channel spacing Modulation Speech coding

200 KHz GMSK Various originals were RPELTP/13

Speech channel per RF channel

8

Channel data rate Frame duration

270.833 kbps 4.615 ms

The GSM cellular technology uses 200 KHz RF channels.

These are time division multiplexed to enable up to eight users to access each carrier. In this way it is a TDMA/FDMA. The core of any radio based system is format of the radio signal itself. The carrier is modulated is using Gaussian minimum shift keying (GMSK). GMSK modulation in GSM is used because it is resilient to noise,radiation outside the accepted bandwidth is lower than other forms of the Phase Shift Keying and it has a control constant power level, which allows higher efficiency RF power amplifiers to be used in the handsets which helps in conserving battery life. GSM bursts are NITTTR, Chandigarh

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used for carrying data as well as control information.GSM cellular system to work on a variety of frequencies, the GSM standard defines GSM frequency bands and frequencies for the different spectrum allocation that are in use around the globe. GSM uses a variety of channels in which the data is carried.These channels are separated into physical channels and logical channels. The physical channels are determined by the time slots where as the logical channels are determined by the information carried within the physical channel [1].

Omnidirectional linearly polarized antennas have been widely used in base station mobile communications because they can reduce the number of cell sectors and the effects of small sectors variation [2]. The omnidirectional antenna radiates or receives equally in all directions. It is also called the non-directional antenna because it does not favor any particular direction. The radiated signal has the same strength in all directions. The gain is a parameter which measures the degree of directivity of the antenna’s radiation pattern. A high gain antenna will preferentially radiate in a particular direction. Antenna gain is defined as the ratio of intensity radiated by the antenna in the direction of maximum output. High gain antennas have the advantage of longer range and better signal quality. Low gain antennas have shorter range, but the orientation of the antenna is relatively inconsequential. If the gain of the antenna goes up, the coverage area or angle goes down.

High gain antennas have narrow beam width and less chance of receiving interface. Lower gain antennas have wider beam width and a greater chance of receiving interface [3].

The simple alternative to the adaptive beam forming antennas is switched beam antennas. The switched beam antennas from multiple fixed beams with heightened sensitivity in particular directions. When the incoming signal detected it determines the beam which is better aligned based on SOI (signal of interest) and switches to that beam to communicate with the user. As the mobile unit moves throughout the cell, the switched beam system detects the signal strength and continually switches the beams as necessary. It subdivides sector into many narrow beams, then each beam is considered as an individual sector serving user or group of users.

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Int. Journal of Electrical & Electronics Engg.

Vol. 2, Spl. Issue 1 (2015)

e-ISSN: 1694-2310 | p-ISSN: 1694-2426

Fig. 1 Block diagram of switched beam system [4].

PSN (Phase Shifting Keying), which forms multiple beams looking in certain directions. RF switch actuates the right beam in the desired direction. The selection of right beam is made by control logic, which is governed by an algorithm. The algorithm which scans all the beams and selects the one strongest receiving signal based on measurement made by the detector. The overall goal of the switched beam system is to increase the gain according to the location of the user [5, 6].

Fig. 3 Channel properties

III. SIMULATION RESULTS

II. PROPOSED NETWORK The proposed GSM network is designed and simulated in Qualnet Software version 5.0.2. The Fig. 2shows the designed and simulated network in software.

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Fig. 4 shows the two calls completed. First between the node 1 and 3 and second call is between the node 4 and 5.

Call duration between node 1 and 3 is 10 Sec. Call duration between node 4 and 5 is 20 Sec. A.

Simulation result of change in antenna gain:

Nodes 1, 2, 3, 4, 5, 6 are MSs. Node 7 and 8 are BTSs.

Fig.2Proposed GSM network.

This network contains various components like MS, BS, MSC and Wireless Subnet Network. Network scenario is developed using coverage area 1500m X 1500m. It is formed by using 7 nodes, node 4 to 7 are MS, 1 & 2 are BS, 3 is MSC, BSs are connected to the MSC through wired links and a default root file is specified to make the appropriate interface between them. The whole setup used 8 channels for traffic and control process. The Fig.3 shows the channel properties.

Fig. 5 Signals received when the gain is changed.

Fig. 5 shows the signal received at 8 nodes. As the antenna gain increases signal received power increases.

B.

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Simulation result by changing antennas:

NITTTR, Chandigarh

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Int. Journal of Electrical & Electronics Engg.

Vol. 2, Spl. Issue 1 (2015)

e-ISSN: 1694-2310 | p-ISSN: 1694-2426

Fig. 6 Signals received power by changing antennas

In above Fig. 6signals received power is changed by changing antennas. The signal received power of omnidirectional antenna is more than the signal received power of a switched beam antenna.

IV. CONCLUSION In this paper author conclude that by the increase in antenna gain signal received power increases. By changing the antenna the signal received power also changes. The signal received power of omnidirectional antenna is more than the switched beam antenna.

ACKNOWLEDGEMENT We heartily thankful to our supervisor, Mrs. Garima Saini, assistant professor, department of electronics and communication engineering, NITTTR Chandigarh for her guidance, support and encouragement throughout the research work. We are obliged to Dr. SBL. Sachan professor and head, department of electronics and communication engineering and all technical and supporting staff of NITTTR, Chandigarh for providing the facilities, help and encouragement for carrying out this work.

REFERENCES [1] Avinash Shivajirao Pawar and Atish Shivajirao Pawar,”Study of the GSM network” International Journal of Advanced Engineering Research and Studies, Vol. I, Issue III, pp. 287-292,April-June, 2012.

[2] XuLinQuan, RongLin Li and Manos M. Tentzeris,”A broadband Omnidirectional circularly polarized antenna” IEEE transaction on antennas and propagation, vol. 61, no. 5, pp. 2363-2370, may 2013.

[3] Joseph J. Carr, ratio tech-notes, directional or omnidirectional antenna.

[4] http://image.slidesharecdn.com/smartantenns-131023072120phpapp02/95/smart-antenna-5-638.jpg?cb=1394008133.

[5] Zhongding Lei, Francois P. S. Chin and Ying-Chang Liang,” Orthogonal switched beam for downlink diversity transmission” IEEE transaction on antennas and propagation, vol. 53, no. 7, pp. 2169-2177, July 2005.

[6] S. Bellofiore, C. A. Balanis, J. Foutz, and A. S. Spanjas, “Smartantenna systems for mobile communication networks, part 1: Overview and antenna design,” IEEE Antennas Propag. Mag., vol. 44, no. 3, pp.

145–154, Jun. 2002.

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