Long Term Evolution ( LTE ) Network Evaluation in the South-West Region of Nigeria

The LTE broadband evolved from an earlier Third Generation Partnership Project system which is known as the Universal Mobile Telecommunication System (UMTS), which evolved from the Global System for Mobile Communications (GSM). The network architecture of this system has been designed with the aim to support a packet-switched traffic with seamless mobility and great quality of service. The main goal of the LTE is to provide a high data rate with low latency and a packet optimized radio access technology that supports deployment of bandwidth. Hence, this study is based on the evaluation of the LTE network in the south-west region of Nigeria. This study evaluates the LTE network strength in the South-West region of Nigeria. Questionnaires were administered among users in these areas randomly. Thereafter, data were analyzed and research questions were answered from the analyzed results. The results showed that 9Mobile and MTN has the best quality of service of LTE network in South-West, Nigeria, also that the LTE network has not really been active in Osun and Ekiti states.


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Abstract-The LTE broadband evolved from an earlier Third Generation Partnership Project system which is known as the Universal Mobile Telecommunication System (UMTS), which evolved from the Global System for Mobile Communications (GSM).The network architecture of this system has been designed with the aim to support a packetswitched traffic with seamless mobility and great quality of service.The main goal of the LTE is to provide a high data rate with low latency and a packet optimized radio access technology that supports deployment of bandwidth.Hence, this study is based on the evaluation of the LTE network in the south-west region of Nigeria.This study evaluates the LTE network strength in the South-West region of Nigeria.Questionnaires were administered among users in these areas randomly.Thereafter, data were analyzed and research questions were answered from the analyzed results.The results showed that 9Mobile and MTN has the best quality of service of LTE network in South-West, Nigeria, also that the LTE network has not really been active in Osun and Ekiti States.Index Terms-LTE; Broadband; Network Service Quality; Analysis; Network Evaluation.

I. INTRODUCTION
Over the years, networking has evolved from the era of the common wired local area network to the wireless mobile networks, due to the evolution of communication technology, there has been a widespread of smartphones, and this has led to an increase in number of mobile subscribers.According to the statistics gotten from the Nigerian communication commission, the rate at which the penetration of mobile phones has grown over ten years is recorded to be 103.91%with an active subscriber base of 145.5 million, also as noted in [1], the number of internet users in Nigeria hits 91.6 million as at 2017.Due to this increase in the subscriber rate and high demand of increase internet speed the service providers adopted a new advancement in technology, the Fourth Generation mobile network, which allowed users to get an increased bandwidth, this is an advancement of the Third Generation mobile network.
The evolution of wireless mobile network technologies can be classified into various generations based on the level of technology being used.The first generation or 1G was represented by an analog wireless access system primarily for voice traffic.(e-mail: bmkuboye@futa.edu.ng)analog channel was likely to be affected by static noise and did not provide any protection from eavesdropping on the shared media.However, Advance Mobile Phone System laid the foundation to the wireless mobile technology which led to the use of small hexagonal service areas and hence supported frequency re-use across the mobile phones without interference.
The 1G technology was soon replaced by the second generation or 2G technologies which represented the replacement of the analog radio network with digital radio network.The digital technology was more effective than its analog counterpart in the sense that digitized data could be subjected to superior processing techniques making it less likely to be affected by noise.Also, digital technology is focused on discreet bi-level signals as against continuous analog signals making it easier to calibrate and maintain and hence cheaper than analog devices.The 2G technologies could be further classified into Time Division Multiple Access (TDMA) based and Code Division Multiple Access (CDMA) based.This technology led to a temporary development of a new generation which was 2.5G, this represented 2G systems which demonstrated a packet switched domain in addition to the circuit switched domain.General Packet Radio Service (GPRS) was the 2.5G technology used by GSM.GPRS offers a packet switched service over GSM providing data speeds between 56-114 kbps.Enhanced Data Rates for GSM Evolution (EDGE) over GSM and CDMA2000 1xRTT over CDMA were represented as 2.75G technologies though they may well be called 3G technologies as they surpass data rates of 144kbps which was the limit required to meet the 3G technology requirements, but because their data rates were far below the data rates of actual 3G technologies.EDGE provides data rates of 236.8 kbps while CDMA2000 deployments limit the data rates at 144kbps.This temporary period led to the evolution of the third Generation of Mobile technology, better known as 3G.The International Telecommunication Union (ITU) under the International Mobile Telecommunications Program set the minimum data rate of 144kbps for any technology to qualify to be a 3G technology.However, most technologies which are classified under this category by far surpasses this minimum limit and provide data rates typically between 5-10 Mbps.3G Technologies attain better spectral efficiency (more bits / Hertz) over wide area mobile phone networks allowing for higher data rates and better services.The first pre-commercial and commercial 3G technology was installed in Japan followed by South Korea.
UMTS based 3G technologies have increased their data rates and network architecture to 3 The Fourth Generation had an edge over the Third Generation because it had a higher speed rate which was capped at 100Mbps on wired LANs compared to the Third Generation which was at 14Mbps.LTE has allowed improvements in regards to the efficiency spectrally and also increasing the bandwidth.
The LTE broadband evolved from an earlier Third Generation Partnership Project system which is known as the Universal Mobile Telecommunication System (UMTS), which evolved from the Global System for Mobile Communications (GSM).The main goal of the LTE is to provide a high data rate with low latency and a packet optimized radio access technology that supports deployment of bandwidth.The network architecture of this system has been designed with the aim to support a packet-switched traffic with seamless mobility and great quality of service.
LTE is the successor technology not to only the UMTS but also the CDMA 2000, it introduced higher data rates which peaked at over 300Mbps which is faster than the normal 4G [2].

II. RELATED WORKS
As stated in [1], are different values as LTE performance that depends on parameters such as system bandwidth, multi antenna schemes, FDD or TDD operation, etc.The researcher's main objective of study was to determine physical layer throughput of LTE Release 8 in different scenarios for uplink and downlink.TDD and FDD operations were considered.Based on the system bandwidth that varies from 1.4 to 20 MHz, different amount of physical resources is available during a radio frame.Physical channels and reference signals were mapped to these resources.He maintained that by calculating the overhead of reference signals that actually do not carry information to higher layers and control channels that convey control information, the number of resource elements allotted for data transmission could be determined.The channel mode was assumed to be AWGN (Additive White Gaussian Noise) and normal cyclic prefix used.The LTE turbo code basic code rate was 1/3 and supported modulation schemes were QPSK, 16-QAM, and 64-QAM.Hence, the maximum throughput of different scenarios by applying the modulation scheme and puncturing code rate was calculated.His example was a case of 15 MHz bandwidth, two antenna ports, and assigning two FDM symbol for PDCCH, the number of resource elements for PDSCH was 196896 in one radio frame.So applying the modulation schemes of 64-QAM, 16-QAM and QPSK with code rates 0.92, 0.85, 0.71 respectively, the throughput was 108.868Mbps, 66.94Mbps, and 27.959Mbps for each case.The author did a good work though, but his major limitation to the maximum throughput obtained was because of the number of antennae he used which employs 2X2 MIMO.Higher throughput is expected with 4X4 MIMO which was still under development during the time of his research.
Authors in [3] performed evaluations of different approaches to a practical implementation of the packet scheduling algorithm through a custom LTE system simulator using different approaches.The evaluations of three basic packet scheduling algorithms (Maximum Rate, Proportional Fair, and Radio Resource) for the downlink of 3GPP LTE systems were considered.As a platform for the evaluation of the algorithms, a system level simulation of the LTE was developed using MATLAB.The comparison among the algorithms was performed under various channel fading models.
Khan [4] stated that the PF (Proportional Fair) scheduling method, on the other hand achieved a good trade-off between the throughput and the fairness among UEs, they did not perform an in-depth analysis and only provided a MATLAB simulation without also presenting a practical scenario.There works however was still relevant to this work as it provided insight to some areas to be considered in the field test.
Okonkwo et.al, [5], performed a simulation evaluation on the LTE and UMTS networks using a method that involved modelling of UMTS and LTE network nodes, their interfaces, properties, protocols, latency, data rates and handover techniques using software.They also employed another approach which involved the developing mathematical models that emulate the behavior of the different message signal flows that occur during the voice and data processes.The mathematical model however was more useful in voice/data handover KPI than other KPIs and consequently the model was used for just handover.Based on these mathematical models, equations were derived for the service interruption time of the handover scheme, the simulation software used was 'LENA, simulations were performed with theoretical network values.The choice of network values was from typical values usually found in UMTS and LTE networks and consistent with MTN (Nigeria) networks for the purpose of this work.Results obtained show that LTE system using orthogonal Frequency Division Multiplexing (OFDM) and scalable bandwidth, together with more advanced MIMO schemes, provides better data rates and improved overall KPIs than the UMTS.
In addition, Reinikaine [6], stated that Carrier Aggregation (CA) is an essential technology component in LTE-Advanced (LTE-A).CA is capable of combining up to five Long Term Evolution (LTE) carriers to be used for multicarrier transmission in both downlink and uplink.CA provides increased throughputs, additional capacity and possibilities for load balancing.He also performed an evaluation of the LTE-Advanced Carrier Aggregation, furthermore, the results from CA performance measurements are analyzed and presented.The measurements were conducted in live network to evaluate the end-user experience.The objective was to determine whether CA is capable of delivering the performance that could be theoretically expected.The performance was measured in LTE-A radio network using 2 × 20 MHz bandwidth with 2 × 2 MIMO configuration and Category 6 User Equipment (UE).Only downlink CA was measured, since uplink CA capable UEs were not commercially available.The performance was evaluated with stationary and mobility measurements.The results indicate that CA is capable of providing the expected performance gain.In good radio conditions the maximum downlink throughput is close to the 300 Mbit/s.The delay in secondary carrier addition was measured to evaluate the impact on user experience.The results indicated that the secondary carrier addition after connection setup or handover was sufficiently fast, and do not have an impact to the user experience.
The work of [7] evaluated the cell coverage area for LTE and WiMAX technology theoretically for different frequencies and environments in wireless communication systems.The evaluation was done based on the propagation model-COST HATA231 model, which is suitable for LTE in various environments.Based on this model, it was determined that the cell radius and coverage area under some real world application are different for different continents of the World as per licensed spectrum.They also compared the cell radius obtained in the case of LTE and WiMAX under different environments and frequencies.The comparison results revealed that the LTE technology does not only covers greater area than WiMAX for similar frequencies but also provides high-speed, better QoS and "all-IP" mode of communications.As the results, it is highly expected to be the best candidate for future wireless communication system.
Jemmali, [8] considered both an analysis and a numerical evaluation of the performance of MIMO radio systems in the LTE network environment.More specifically he considered the physical layer of the OFDM-MIMO based radio interface.In the first step, a theoretical analysis of the bit error rate of the two space-time codes adopted by the LTE norm, namely the SFBC 2 × 1 and FSTD 4 × 2 codes, as a function of the signal upon noise ratio was presented.In this review, analytical expressions were given for transmission over a Rayleigh channel without spatial correlation which were then compared with the Monte-Carlo simulations.In the second step, the capacity of the channel was obtained using these codes on a Rayleigh fading channel.The results showed that the simulated throughput almost reached the capacity limit.As a different topic, in this review, the MIMO systems based on antenna selection were considered, by using order statistics they developed analytical expressions for the error rate on a Rayleigh channel without antenna correlation.In order to validate the numerical results, an algorithm implementing antenna selection at the receiver were developed and used in the simulations.
Authors in [9] proposed the evaluation of QoS provided by a LTE cellular data network, the analysis was based on the live data that were collected on commercial cellular network and compared against broadband wireless LAN.A methodology for QoS assessment based on a relatively small set of Key Performance Indicators (KPIs) was devised.A laptop, a LTE enabled cellular device and a data collection software were used, the collection software was used to measure the following data services: HTTP Web browsing, FTP download, FTP upload, video streaming, and ping, data collected were processed in order to get major statistical measures, such as minimum, maximum, and average values for all collected KPIs.Data Quality Index (DQI) was used to evaluate the Quality of Service (QoS) of cellular data networks, the scoring system that was used for the DQI was from one to five, where one indicates the lowest quality, and five indicates the highest quality.A network with highest DQI score was perceived to be the one with the best user experience.After the analysis, they then compared the results of the LTE drive test with home Wi-Fi and office Wi-Fi, the DQI showed that LTE had the best user experience where they LTE, home Wi-Fi and office Wi-Fi scored 4.3, 3.13 and 3.94 respectively.
A performance review in [10] on different path loss models for LTE which stated that the concept of path loss and network planning were very important to deployment of telecommunications, a comparative analysis of the five path loss models (e.g.3GPP model, COST231 Hata model, Modified Hata model, User and Winner model) used in LTE networks was simulated in urban and suburban environment using a MATLAB-based simulator; LTE MAC-LAB developed by is-wireless Poland.After the analysis, it was obvious that the 3GPP model performed better in all scenarios similar to the free space path loss, also during the test it was discovered that the winner model showed a constant behavior when user equipment height was changed at 20km from the eNodeB in all terrains.
The study [11] conducted in 2017, made a performance evaluation of broadband network in Nigeria, which includes from 1G to 4G (LTE).In this evaluation the research methodology adopted was the use of questionnaires, these questionnaires were used in four different locations which was consisted of the rural and urban regions of the country.After the collection of data with the questionnaires, the results were analyzed with the aid of a statistical tool which was Statistical Package for Social Sciences.The results of the analysis carried out showed that broadband networks in Nigeria are still developing and also need lots of improvements.
A research on the impact of differentiation and scheduling of resources in the transport network on the end to end performance of voice over LTE network [12].The research was focused on voice over data traffic and analyzed its performance for various transport network scheduling algorithms.The results presented that proper classification and scheduling of resources in the transport network, will improve voice capacity in LTE.It was also showed that if voice call was first on the list of priorities it was going to totally affect the performance of data traffic.As a result, voice and data users were categorized into different levels of priority and their performance in this scenario was looked into.The results showed that by classifying voice users into different levels of priority, the capacity is increased when compared to mapping them to a single specific service class.The work was simulated using OPNET.
To this end, authors in [13] provided little information about the performance of 4G networks in the sub-region, they measured a 9.62Mbps downlink throughput for a deployed WiMAX network under normal circumstances of a network in the Sub-Saharan African terrain.This throughput performance was poor when compared with reported network performance of deployed LTE networks in Europe and Asia.Documented results of the performance of LTE under various deployment scenarios in Europe and Asia were also presented by [14].Barayan, and Kostanic [15] reported that the measured downlink throughput was 52Mbps while a maximum throughput of 32Mbps was measured by Gabriel, [16] and it was compared to the simulated throughput of 60Mbps and 35Mbps respectively.Despite the differences between the measured and simulated results, an impressive performance of the deployed networks was realized confirming the assurance LTE.

III. METHODOLOGY
In this study, the method that was used was the quantitative research method.Quantitative research method emphasizes objective measurements and the statistical, mathematical or numerical analysis of data collected through polls, questionnaires, and surveys or by the manipulation of existing data through the use of computational techniques.This method of research focuses on gathering numerical data and generalizing it across groups of people.
For this research, an online questionnaire method was employed.The online questionnaire method is a means of gauging the coverage and quality of service of LTE in the states in the south western geopolitical zone of Nigeria.The distribution of questionnaires to selected individuals is a very important method often used by qualitative researchers.The rationale for using the questionnaire method is to enable the researcher to find out what is on their mind, what they think and how they feel about something.
This study critically aims at gathering of information received from the online questionnaire that was being sent to certain numbers of individuals, specifically users of the LTE technology in the states in the aforementioned geopolitical zone in Nigeria on how the LTE technology fares in their location, ranging from the quality of service of several service providers.
For this study, the population from which the samples were derived consists of the following groups of participants/respondents: a. Smartphone users.b.Students.c. Graduates (Employed and Unemployed).d.Tech-savvy individuals.In this study, the purposive sampling method was used for the selection of the participants.Purposive sampling refers to intentionally chosen sample according to the needs of the study.
In this section, the components of the methodology are broken into two; a. Data Collection b.Data Analysis

A. Data Collection Method
In the course of compilation of data, two methods of data collection techniques were used.This was done in order to collect adequate and relevant data to address the research objectives of this study.Though, the qualitative method was used.This data collection method is divided into two namely; 1) Library Research Ramesh described library research as a process dealing with the analysis of evidences such as historical records and documents.Also, it means gathering data from library materials which consists of textbooks, both published and unpublished academic documents such as journals, conference proceedings, dissertations and theses.Library research also includes information gathered about the research from internet search.Data gathered via library research is categorized as the secondary data.Secondary data means the data is readily available and is used by anyone besides researchers.

2) Field Research
Field research composes a number of research methods to solve the existing research problems such as case study, interview and observation.This research adopted the use of online questionnaires; a selection of the participants that were being sent the questionnaires.In this context, questionnaires will be considered because it covers a larger population than face-to-face interviews.The use of questionnaires is one of the ways used to obtain primary data.Primary data is known to be data which was collected during the conduction of a particular research.The data will be collected in the execution of an experiment.Therefore, in order to obtain primary information, the use of questionnaires was employed.This process encouraged the participants to respond to the questions as accurately as possible.Some of the data gotten from the questionnaire is represented in Tables I-III:

B. Method Adopted for Data Analysis
Data analysis is a very important segment in the research.In the qualitative research, data analysis probably carries more negative connotations than any other single part of the research process.This could be attributed to the fact that in qualitative studies, data are usually recorded in the form of words; descriptions, opinions and feelings rather than numbers.
Data analysis is the process that most differentiates quantitative from qualitative research.The current research adopted the fundamental approaches in analyzing the output from the data gotten from the questionnaire by converting the facts to numbers and performing the computation of the data with the use of an analytical programming language which is python and other libraries related to the programming language.The data gathered from questionnaire will be arranged and summarized according to categories such as the most used LTE service provider in each state, service provider with the best quality of LTE service in each state, the most used LTE service provider in the whole of the south western geopolitical zone of Nigeria, service provider with the best quality of service in the whole of the south western geopolitical zone of Nigeria and the service provider that has the best LTE service based on quality of service and number of users .

C. Statistical Model for Data Analysis
The model that was employed for this analysis was linear regression, linear regression is a way to model the relationship between two variables.
where X is the independent variable and Y is the dependent variable  (3) Equations 1-3 in relation to the data from the questionnaires denote the independent variable as the service provider of each network while the dependent variable for the regression model in this case is the quality of the service of the networks.

IV.
Quantitative data has been gathered from primary and secondary data sources have been analyzed in this chapter.Primary data has been gathered from specific locations in the focus geopolitical zone in Nigeria which is the south west geopolitical zone.

A. Characteristics of the Respondents
This section summarizes the characteristics of the respondents of this research.Fig. 1 shows that the majority of the respondents that participated in this research were males with 66.1%.This factor is based on the fact that the society has a larger percentage of males present.This distribution of level of network used by the respondents is shown in the Fig. 2. Majority of the respondents use MTN with a total of 34.9% respondents.26.6% of the participants of this research used Airtel, 14.7%, 13.8%, 4.6%, 2.8%, 1.8%, 0.9% were users of 9Mobile, Glo, Spectranet, Ntel, Smile and Swift respectively.The total number of responses considered for this research was 109.This classification shows that the southwest region of Nigeria has low coverage of LTE network, Fig. 3 shows that there are few people that make use of LTE in the zone mentioned above either based of poor network connectivity or other factors hindering the service providers.In this distribution level, it shows that Lagos state has the highest number of LTE network users with 60.8%, also in Fig. 5, it shows us that Osun state has least amount of LTE network users, with Ogun, Oyo, Ondo and Ekiti having 13.7%, 11.8%, 7.8%, 3.8% respectively.This chart shows that the state that has benefited the in the evolution of mobile networks to LTE is Lagos state, other states that are rapidly growing are Ogun and Oyo state.

B. Statistical Analysis of Parameters
The rating scale of the quality of LTE network varies from 0 to 5, where 0 represents very poor and 5 represents very good.Statistical data show that Airtel has the highest number of subscribers in the south-west geo political zone, also analysis shows that MTN and Airtel are most used LTE service providers, according to the feedback gotten from the respondents that participated in the research.In Fig. 5, we can attest based on the data that was gotten from the research that Lagos has the best coverage of LTE network.
During the gathering of data that was needed for the evaluation of the LTE network in the south western geopolitical zone in Nigeria, I decided to analyze the quality of the LTE network based on both the networks and states, with the aim of checking for the LTE network service with the best quality of service and the state that has the best quality of service being rendered with the LTE network.This would be shown in the figures below.In Fig. 6, the data from the research that was carried out has been represented in form of bar chart.This bar chart shows that Ntel, spectranet, 9mobile and MTN has the best quality of service in the whole of the south western geopolitical zone, where the poorest service provider averaging a rating of 2 is Swift, Other networks including Glo, Airtel and Smile averaged a rating of 4 which showed that they also provided good services.9 shows that from the best fit line, MTN, 9mobile, Ntel and Spectranet has a little deviation from the highest point in the scatter plot compared to other service providers which implies that the service providers above have the best quality of service in the whole of the south-west region of Nigeria.

V. CONCLUSION
The implication of the results of the various analyses performed in this study is that mobile network service providers with LTE in the south west geopolitical zone of Nigeria are still developing and need a lot of improvements.Therefore, the government and the service providers must work together to fast track the full operation of LTE network services in the south west geopolitical zone of Nigeria; inability to do this will continue to delay the gains of Information Technology to the economic growth of Nigeria.Thus, from the data gathered in this study, it is recommended that the regulatory body of network service providers in Nigeria which is the Nigerian Communications Commission (NCC) should advise the mobile network service providers to improve in the provision of the LTE network service in the south west region of Nigeria.

Fig. 4 .
Fig. 4. Distribution Based on LTE Enabled NetworksThis distribution of level of LTE network used by the respondents in the south west geo political zone is shown in Fig.4.Majority of the LTE users make use of MTN and Airtel which both have 23.5%, while 9Mobile, Glo, Spectranet, Ntel, Smile and Swift have 15.7%, 15.7%, 9.8%, 5.9%, 3.9% and 2.0% respectively.

Fig. 6 .
Fig. 6.Quality of LTE Network based on Service provider

Fig. 7 .
Fig. 7. Quality of LTE network based on States

Fig. 7
Fig. 7 represents the coverage/quality of service of LTE based on the states in South-West.This shows that Lagos and Oyo have the best LTE service coverage averaging a rating of 5, while other states such as Ogun, Osun, Ondo, Ekiti and Oyo averaged a rating of 4 each.

Fig. 8 .
Fig. 8. Scatter Plot of Quality of Network based on Networks

Fig.
Fig.9shows that from the best fit line, MTN, 9mobile, Ntel and Spectranet has a little deviation from the highest point in the scatter plot compared to other service providers which implies that the service providers above have the best quality of service in the whole of the south-west region of Nigeria.
The Advance Mobile Phone System in United States and the Total Access Communication System in most parts of Europe represented this generation.The

TABLE I :
SEX OF RESPONDENTS

TABLE III :
NETWORK PROVIDERS OF RESPONDENTS