Nigerian Journal of Technology (NIJOTECH) Vol. 34 No. 3, July 2015, pp. 538 – 545 Copyright© Faculty of Engineering, University of Nigeria, Nsukka, ISSN: 0331-8443 www.nijotech.com http://dx.doi.org/10.4314/njt.v34i3. 161616 DEVELOPMENT OF BASE TRANSCEIVER STATION SELECTION ALGORITHMALGORITHM FOR COLLOCATION ARRANGEMENT T. M. Ajibola 111, N. T. SurajudeenSurajudeen----BakindeBakinde 2,* and S. A. Y. Amuda 333 1, 2, 3 DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING, UNIVERSITY OF ILORIN , KWARA STATE , NIGERIA EEE-E---mailmail addresses: 1 [email protected], 222 [email protected], 333 [email protected] ABSTRACT Placement of base transceiver station (BTS(BTSssss)) by different operators on a particular site as cocollocationllocation site, so as to save cost and reduce the number of people who are at risk of radiation in BTSBTSssss located places as compared to each operator having different BTSBTSssss is the new trend in Nigeria telecommunication indusindustriestries development. Collocation of base stations is much safer when compared to scattered base station telecommunication operators because of the radiations. Although the International Commission on NonNon----IonizingIonizing Radiation Protection (ICNIRP) viewed that the presently existing scientific verification that prolonged contact with low frequency magnetic fields is more often than not connected witwithh an increased danger of childhoodchildhood leukaemia is too frail to form the basis for exposure guidelines. This work includes the study, analysis and proposal of a collocation scheme based on collected data of the number of BTS already sited in University of Ilorin, Ilorin, Nigeria as a case study. A drive test conducted with Transmission Environmental Monitoring System (TEMS) equipment was carried out on the existing BTSs, and a linear algorithm optimization program based on the spectral link efficiency of each BTS was developed, the output of this site optimization gives the selected number of base station sites to be used for the collocation arrangement, and the BTSs site with the best spectral link efficiency are selected in accordance with the output of the site optimization for the collocation. Keywords: absolute radio frequency channel number; base transceiver station; collocation; radiation; spectral link efficiency. 1. INTRODUCTION positioning of the BTS as well as the strategic The deployment of many base transceiver stations inclination of the communication antennas can (BTSs) by different telecommunication operators, influence the quality of service rendered to the scattered all over the vicinity of residence, work and custumers. Due to this reason some base stations are schools, has become a great concern for economic located on a hilly terrain free from blockage of any reasons and exposure to radiation by the general structures in order to enhance quality connectivity public within the BTS environment. and coverage [1]. Each BTS has between 1-16 A BTS is a permanent location in a mobile cellular transceivers depending on the density of users in the network used for radio communications with mobile cell [2]. units. The major work of a BTS is to allow a good The Federal Communications Commission (FCC) process of information transmission and reception defines collocation as the mounting or installation of between mobile stations [1]. The base station consists antennas from different GSM operators on an existing of radio channels each having its absolute radio tower, building or structure for the purpose of frequency channel number (ARFCN), transmitter and transmitting and/or receiving radio frequency signals receiver antennas. These antennas which are mostly for communications purposes [2]. directional antennas for mobile telecommunications In 2001 when Global System for Mobile are positioned strategically on a tower in order to Communications (GSM) was introduced in Nigeria, render services to certain geographical area. The Nigerians embraced it with a lot of passion to enjoy all location of a BTS is of crucial importance; the the benefits of the new mobile communications * C* CorrespondingC orresponding author, Tel: +234+234----813813813813----728728728728----8435843584358435 DDDEVELOPMENT OF A BBBASE TTTRANSCEIVER SSSTATION SSSELECTION AAALGORITHM FFFORFOR CCCOLLOCATION AAARRANGEMENRRANGEMENTTTT T. M. AjibolaAjibola,, et al technology. The pioneer then was Econet Wireless infrastructure-sharing arrangements, as well as (now Airtel) and MTN before Globacom was licensed promoting fair competition through the grant of equal in 2003. Etisalat joined the race of telecoms service access to operators' installations and facilities on providers in 2008. Full scale service delivery was mutually agreed terms. Rule 4 of the guidelines enjoyed as calls went through without the slightest specifies the infrastructure to be shared, as congestion. As the number of subscribers increase, it encouraged by the NCC as itemized thus: was expected that telecoms operators will increase • Rights of way infrastructure rollout at a commensurate level to that • Masts, poles, antennae and tower structures of subscriber’s growth. But little attention was paid to • Ducts, trenches and spaces in buildings infrastructure improvement until a time when • Electricity (from public or private sources) network congestion sets in, leading to subscribers [6]. experiencing poor services delivery [3]. Nigerian Where the sharing of infrastructure such as rights of government policy had consistently put pressure on way and electricity is conditional on securing approval the GSM operators to improve their QoS with from a granting authority, such approval should be projection that there will be need for about 60, 000 obtained before the sharing arrangement can be BTSs by 2018 [2] and one of the ways to achieve this finalised [6]. target is to allow collocation scheme among telecommunication operators. 2.2.2. RELATED WORKS The health and cost implications of the increasing The principal mandate of NCC as stated in its guideline number of these BTSs influence both the government for collocation is to launch a structure within which and the Association of Licensed Telecoms Operators of operators can discuss collocation arrangements, and Nigeria (ALTON) to encourage collocation by check that the occurrence of avoidable duplication of proposing the appropriate regulations and legislations infrastructure is minimized or totally avoided and to for the collocation scheme [4]. This collocation scheme keep the environment by reducing the spread of is not only to reduce telecoms infrastructures but also infrastructure and facilities installation, [7]. to manage the system’s energy and to ensure increase The collocation arrangement definitely cause physical in broadband penetration and wider coverage area significant changes to existing wireless mast or base without cross-signal or noise interference. station. The significant change can be in the form of Human health threat becomes the consequent issue of placement of a proposed antenna that would involve the increasing BTS sites as non – ionizing radiations adding an extension to the body of the mast to protect from base station sites have been reported to cause the antenna from severe weather or to connect the considerable health hazards, such as brain tumor, eye antenna to the mast through cable. Currently the most cancer to mention but a few [5] even though these commonly shared infrastructure among operators is health effects have not been medically proven. The passive infrastructure, as it is easier to contract its set- main fear is focused on long-term exposure to these up and maintenance, [8]. radiations. This concern especially originated from the Ever since the introduction of telecommunication, the use of some mobile phones and human closeness to equipment and the deployment of the infrastructure base stations for a long time, as some studies have of whatever type has been resource demanding from a shown that the radiations from these two sources business point of view, operators in the recent past were associated with some health problems like birth have embraced collocation of base station masts. The defects, brain tumors, lymphomas, and memory cost of sharing facilities in a collocation arrangement problems, [5] is practically low, compared to the cost of constructing The first developmental step was taken by the one’s own infrastructure, for this reason there is faster Nigerian Communication Commission (NCC) by returns on investment and an opportunity to focus issuing the Guidelines on Collocation and more on the core business of the companies by Infrastructure Sharing with presumption that it will providing telecoms services [8]. reduce or eliminate avoidable costs in the The challenges facing the optimal selection of base telecommunications industry, including capital station transceiver site for collocation are the non – expenditure on supporting infrastructure [6]. The uniformity in the quality of service in a geographical guidelines established a framework within which location, coverage area and the interference of operators can negotiate collocation and neighboring base station sites. The challenge of Nigerian Journal of Technology, Vol. 34, No. 3, July 2015 539 DDDEVELOPMENT OF A BBBASE TTTRANSCEIVER SSSTATION SSSELECTION AAALGORITHM FFFORFOR CCCOLLOCATION AAARRANGEMENRRANGEMENTTTT T. M. AjibolaAjibola,, et al optimum selection of BTSs was considered using the collection method employed in achieving the goal