E. T. Tchao

Distributed denial of service (DDoS) attacks are a major threat to any network-based service provider. The ability of an attacker to harness the power of a lot of compromised devices to launch an attack makes it even more complex to handle. This complexity can increase even more when several attackers coordinate to launch an attack on one victim. Moreover, attackers these days do not need to be highly skilled to perpetrate an attack. Tools for orchestrating an attack can easily be found online and require little to no knowledge about attack scripts to initiate an attack. Studies have
been done severally to develop defense mechanisms to detect and defend against DDoS attacks. As defense schemes are designed and developed, attackers are also on the move to evade these defense mechanisms and so there is a need for a continual study in developing defense mechanisms. This paper discusses the current DDoS defense mechanisms, their strengths and weaknesses.

Due to non-existent commercial power, unreliable power
supply and high cost of running diesel generators at remote
locations in Ghana, it is becoming increasingly uneconomical
for network operators to maintain off-grid communication
infrastructure at remote locations since subscriber numbers
are relatively low in these locations. In order to surmount
these challenges, network operators are turning towards the
use of alternative power supply systems to power their offgrid
infrastructure in these remote areas. This paper seeks to
perform a techno-economic evaluation of two commonly used
power supply systems for BTS in these remote locations;
namely dual prime generators and hybrid power systems. The
performance of two off-grid sites using dual prime generators
and hybrid power systems have been evaluated at a 100% site
load. The load per day from the two sites was measured as
100W on the average. During the evaluation process, it was
realized that the hybrid efficiency operates within a 2%
tolerance of the simulated results and provides fuel saving of
61.70% as compared to the site using dual prime generators at
a 100% site load per day. It was also realized that, the hybrid
system has the capability to expand to 5 rectifier modules
although the maximum is limited by the size of the generator.
With a greater amount of rectification available to increase the
rate of recharge for the batteries, it is possible to improve on
the reduction in diesel run time and thereby further increase
operational expenditure (OPEX) savings to more than 80%.

The adoption of Bring Your Own Device (BYOD)-also known as Bring Your Own Technology (BYOT), Bring Your Own Phone (BYOP), or Bring Your Own Personal Computer (BYOPC)-is a policy which allows people access to privileged resources, information and services available on the private computer network of an organization using their own personal computer devices. BYOD, since its emergence in 2009, courtesy of Intel, is now a common practice in many organizations. Academic institutions that attempt to implement BYOD, can derive many benefits as well as many risks to its network infrastructure, largely security-based. This paper presents an assessment of a WLAN network which has been deployed for a campus-wide data centric e-learning platform at Kwame Nkrumah University of Science and Technology (KNUST) towards the overall objective of achieving a barrier free internet access to enhance the teaching and learning process at the university. The paper subsequently evaluates the WLAN infrastructure, its accompanying BYOD setup , and associated likely security risks and threats, and recommends appropriate solutions.

Lake Volta is the world's largest man-made lake by surface area, and the fourth largest by water volume. Located completely within Ghana, it has a surface area of about 8502 km 2 (3283 square miles). Like many other lakes on the African continent, Lake Volta is a major natural resource for Ghana, storing water for the operation of the hydroelectric dam, water supply for domestic, agricultural and industrial purposes, habitat for diverse aquatic species, an avenue for recreational activities, means of navigation between the north and south parts of the country, and a climate modulator for the tropical region. The lake has experienced variable water level and surface area changes attributable to climate change and excessive water abstractions. Using histogram thresholding techniques, this study produced binary images and vector maps of the lake. Spatial extent mapping of the lake using Landsat TM 1990, ETM + 2000 and ETM + 2007 images indicated the lake experienced both increased and decreased surface area changes during the study period. The lake's surface area varied by about 197 km 2 between 1990 and 2007, with the water level fluctuating between AE7 m. Factors thought to be contributing to these changes include human factors (regulated flows, deforestation, increased water abstractions and pollution) as well as natural phenomenon (climate change, water runoff and subsequent sediment transport).

One of the salient factors to look at during wireless network planning is developing a modified path loss prediction models to suit a new environment other than the one it was originally designed for. This helps to give accurate predictive outcomes. This paper seeks to demonstrate the effects of applying correction factors on radio propagation model used in planning for 4G-WiMAX network through a comparative analysis between estimated and field data collected on received power for a 4G-WiMAX site. Four existing models were considered for this research; COST 231 Hata, Extended COST 231 Hata, SUI (Stanford University Interim) and Ericsson models. In order to optimize and validate the effectiveness of the proposed models, the mean square error (MSE) and correlation coefficient were calculated for each model between the predicted and the measured received power for the selected area before and after applying an appropriate correction factor. Based on this, the Extended COST-231 Hata prediction model proved to correlate well with the measured values since it showed least Mean Square Error (MSE) but with highest correlation coefficient. Through comparative analysis of the corrected models, the Extended COST-231 Hata model could be applied for effective planning of the radio systems in Ghana and the sub-region at large.

In Ghana and many countries within Sub-Sahara Africa, Long Term Evolution (LTE) is being considered for use within the sectors of Governance, Energy distribution and transmission, Transport, Education and Health. Subscribers and Governments within the region have high expectations for these new networks and want to leverage the promised enhanced coverage and high data rates for development. Recent performance evaluations of deployed WiMAX networks in Ghana showed promising performance of a wireless broadband technology in supporting the capacity demands needed in the peculiar Sub-Saharan African terrain. The deployed WiMAX networks, however could not achieve the optimal quality of service required for providing a seamless wireless connectivity demands needed for emerging mobile applications. This paper evaluates the performance of some selected key network parameters of a newly deployed LTE network in the 2600 MHz band operating in the peculiar Sub-Saharan African terrain under varied MIMO Antenna Configurations. We adopted simulation and field measurement to aid us in our evaluation. Genex Unet has been used to simulate network coverage and throughput performance of 2X2, 4X4 and 8X8 MIMO configurations of the deployed networks. The average simulated throughput per sector of 4X4 MIMO configuration was seen to be better than the 2X2 configuration. However, the percentage coverage for users under the 2x2 MIMO simulation scenario was better than that of the adaptive 4x4 MIMO configuration with 2x2 MIMO achieving 60.41% of coverage area having throughput values between 1-40Mbps as against 55.87% achieved by the 4x4 MIMO configuration in the peculiar deployment terrain.

The massive development and investment in the Ghanaian telecommunication sector and the act of deregulation in the industry has necessitated the deployment of Worldwide Inter-operability for Microwave Access (WiMAX) in the 2500-2690 MHz band to help serve the ever increasing needs of broadband internet subscribers in the country. In order to achieve the goal of providing comprehensive network coverage and high capacity WiMAX networks, a realistic physical layer performance evaluation of WiMAX has to be done to enable network operators understand WiMAX performance and provide a guide for future network deployment in Ghana. This paper undertakes a realistic performance evaluation of a pilot WiMAX network in the urban centers of Accra in Ghana. The physical layer performance of the deployed WiMAX systems is evaluated in terms of measured throughput and received power (RSS). This allows for a direct comparison with simulated results. Due to inherent system losses, it was realized that, not even a system with an optimum 2x2 adaptive MIMO antenna configuration was able to achieve the simulated throughput of 8.45Mbps. The results in the study show that, it is possible achieve a throughput of approximately 6.10Mbps downlink and 2.08Mbps uplink with the most robust modulation scheme, and a speed of 60mph in a densely populated urban environment making WiMAX a bright prospect for large-scale deployments in Ghana.

The exponential growth in technology has impacted development programs of African nations. This has translated to two activities; (i) specific nations acquiring the technologies needed for their development, and (ii) providing the necessary skills to the cadre of technicians, technologists, and engineers to not only deploy the technologies, but as well to operate and maintain them. Deployment of the technologies requires an appreciation of the environment in which the technologies will be used, and this in turn entails a good understanding of the ambient conditions and how these will impact the operational conditions of the deployed technologies. This is particularly necessary for wireless applications. Research relating to these technologies is also undertaken by students and faculty members at universities and colleges with the view to providing solutions to some of the needs of the people. This paper discusses judicious selection of research topics, and research methods that will...

In Ghana, mobile subscribers who weren't satisfied with the services of their mobile service providers had no option but to give up their numbers when switching service providers. As such, subscribers were reluctant to switch from their operator to a competitor thereby preventing effective competition in the Ghanaian mobile communications sector. This necessitated the National Communications Authority (NCA) to develop a Mobile Number Portability (MNP) Policy in consultation with the mobile Service Operators. This MNP Policy has been recently implemented successfully enabling mobile subscribers in Ghana who were hitherto reluctant to bear the cost and inconvenience of switching operators, to fully exercise their freedom of choice. Analysis of data shows subscribers porting in and out of all the mobile communication networks. The average net effect of porting in and out as at March 2013, expressed as a percentage of a network's most recent reported subscriber base was about 4....

This paper examines the implementation of Mobile Number Portability (MNP) in Ghana and presents the experiences of subscribers with the implemented MNP policy. According to a cost-benefit analysis of the portability process, it is evident that the over 19 Million Mobile subscribers satisfy the minimum market size below which overall benefits cannot be felt. From the study, we argue that, even though the homogeneity of services provided by the Mobile Network Operators (MNO) in Ghana do not provide appropriate incentives to enable subscribers to port out of a network and thus the initial recorded lower porting rate, the threat of porting has led to improved competition among operators resulting in lower tariffs, better services and improved Quality of Service (QoS) of the networks. Hence the implemented MNP policy could be considered as successful. The competitive effects resulting from the introduction of MNP in the telecom sector have been discussed thoroughly.