C. Ohaneme

Radio frequency interference (RFI) in a co-located network is a major challenge faced by cellular network operators. The RFI issues are prominent when the radio frequency transceivers consisting of two or more co-located networks operate within close or adjacent frequency bands. This paper presents the mechanisms of RFI caused by spurious emission and receiver blocking in a co- located network and proffer industry solution through the application of various mitigation techniques. One method may reduce a particular type of interference to a certain level, a combination of two or more methods can conveniently reduce the interference to an acceptable level. The advent of smart-phones and affordable mobile communication services has led to an exponential growth in the wireless subscriber's base. This rapid increase motivated the mobile network operators to build more cell sites to enhance better coverage and improved quality service delivery. The drive to meet this goal by the network operators has led to incessant proliferation of new cell towers which are capital intensive. In this regard, a co-location, which has recently become a common network build-out strategy, where different cellular systems share a common site, space and structures for the location of base station active equipment and the Radio Frequency (RF) distribution system. It was introduced by the International

Despite the presence and use of modern aviation equipment and instrumentation, there are still regular occurrences of air wish ups with very grave consequences. Often this has been attributed not only to equipment failures but to the inability of the operators to read or understood the role of nature in air navigation. These natural effects are the cloud cover, rainfall (both the volume and rate) as well as temperature. This paper uses empirical information of some of these meteorological conditions on radar signal reception to predict weather conditions. The work was carried out at Akanu Ibiam International Airport situated in Enugu, one of the old regional capitals of Nigeria, Enugu (6.42oN, 7.61oE). This was because of its strategic position and weather variations. It is neither of the heavy rainfall area nor of the hot dry zone of the country. It also has some hills around it which gave its name, Enugu, meaning on top of a hill. Using simple model, it was found that as the rainf...

Bending loss is an induced pneumatic effect that inhibits the bandwidth advantage carriage of fibre Optics over other medium for data communication. Information Technology be it audio, image, telegraphy, telephony etcneeds efficient and transparent carrier network system,to enable the output signal be the exact replica of the input signal. Optic fibre has been rated the best medium for signal transmission because of its good characteristic qualities. Despite these high qualities which include:large bandwidth, immunity to electrical andmagnetic interferences, low noise level etc. intrinsic and extrinsic factors have equally mitigated the operational capabilities of optic fibre. The intrinsic factors from molecular displacement of structural composition lead to various types of dispersionwhile the extrinsic factors of temperature and pressureare catalyst in the reduction of power budget and Bit Error Rate (BER).Fibre optics being a fragile material reacts sharplyto pneumatic forces an...

Smart adaptive antenna technology offers a significantly improved solution to reduce interference levels and improve the system capacity. This paper presents an experimental test-bed of a smart antenna system for the comparative performance evaluation of various adaptive beamforming algorithms and the smart antenna itself. The adaptive beamforming algorithm simulated and analyzed in this work includes the Least Mean Square (LMS), Direct Matrix Inverse (DMI), Recursive Least Square (RLS), Sample Matrix Inverse (SMI) algorithms. The results show that LMS algorithm requires about 53 iterations before it can finally converge. The DMI algorithm is computed for a number of samples and hence it does not require iterations in its calculations. It has faster convergence than LMS, but characterized by numerical instability and increased computational complexity due to matrix inversions. The RLS algorithm requires less number of iterations (about 10 iterations before it converges). For small n...

A number of empirical propagation prediction models for mobile radio communication systems are available in the literature. However, the accuracy of these models suffers when they are used in an environment other than that for which they have been developed. In this research work, a set of propagation measurements taken at 800 MHz band in the suburban city of Awka, Nigeria is used to develop path loss prediction model for suburban environment. Hata and COST-231 Hata models which are widely used for path loss prediction in GSM and CDMA systems are compared with the results of the developed model. The results of this research assist mobile cellular network designers in carrying out accurate analysis and design, deployment and management of their networks.

This paper presents the derivation of an analytical close form expression for the calculation of the call blocking probability for Distributed Dynamic Channel Allocation Scheme under power control (DDCA – PC). The call blocking probability of this scheme was measured and compared with that of fixed channel Allocation (FCA) and the dynamic channel Allocation (DCA). The system capacity with DDCA-PC is substantially increased by approximately 200% compared to that of DCA or FCA schemes without power control. Finally, the system capacity is increased further with larger DDCA-PC gain control.

15 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Pvt. Ltd. Abstract— Network congestion control remains a critical issue and a high priority, especially given the growing size, demand, and speed (bandwidth) of the increasing wireless services. Congestion control is the problem of managing network traffic or a network state where the total demand for resources such as bandwidth among the competing users exceeds the available capacity. This paper presents a fuzzy logic approach to congestion mitigation in TCP oriented network using University of Nigeria Nsukka (UNN) situated at the South-Eastern part of Nigeria as a case study. Using a deductive study mechanism, an intelligent fuzzy-based algorithm for the congestion management is developed while showing a validation analysis plot of the proposed scheme in relation to other TCP variants such as TCP Tahoe, TCP Reno, TCP-New Reno, TCP Vegas and TCP selective acknowledgments (SACKs), i.e.TCP-TRONVS. From the imp...

This paper presents an experimental evaluation of the signal-to-interference ratio variations in IEEE 802.11b WLAN. Afrihub network at Nnamdi Azikiwe University was studied using a network sniffer called Network Stumbler (NetStumbler). The network has three functional access points at the time of the study. The mean of the detected signal strength of the access points was calculated. Matlab was used to calculate the signal distance and the signal to interference ratio and the analysis were plotted for several scenarios: for one, three, six, ten and thirty interfering access points. It was observed that the signal to interference ratio decreases as the number of interfering access points increases.

1 Abstract— This research seeks to address the problem of congestion in WSNs by identifying the metrics that strictly relate with the philosophy and design of WSNs. From various study on WSN, the focus on experimental Key Performance Indices is yet to be adequately addressed considering periodic event sensing. Consequently this work proposes a congestion management scheme that will detect and overcome the congestion prior to its instantaneous occurrence called Priority Early Detection Congestion Avoidance Mechanism (PEDCAM). The main feature of the proposed algorithm is priority early detection of the congestion pre-occurrence, control optimization and buffer scheduling. With PEDCAM, a comprehensive trace file validation environment based on C/C++ OPNET Modeller was developed. Using this environment, two other similar schemes viz: CODA and CONSEQ which also performs distributed rate adjustment of the FIFO queues on the sensor nodes were compared with PEDCAM. The results from the per...

There is need for a wireless sensor network (WSN) linear congestion control protocol that can fit into a typical linear topology of a pipeline infrastructure. In such a topology, congestion management must capture congestion detection, feedback signaling with rate Regulator, etc. This work presents LRRCCP in the context linear congestion management for wireless sensor deployment. Three major algorithms were presented with relevant problem formulations to comprehensively address congestion issues in WSN deployments. A conceptual framework for the topology design was presented while addressing the shortcomings of the existing congestion control schemes. To leverage LRRCCP, there must be a comparison with existing congestion control schemes based on selected QoS metrics such as throughput, packet loss ratio, efficiency and traffic flow fairness degree in linear topology wireless sensor network. This work finally outlines the implications of the proposed LRRCCP.

Coverage and capacity performance in a cellular network determines the system potentials. If the coverage radius is limited, end users suffer poor service quality, if the system capacity reduces, fewer subscribers will be accommodated. This paper investigated the performance effects of the noise rise caused by the spurious emission from a co-located jammer involving downlink frequency of CDMA2000 and uplink frequency of WCDMA operating at 1.9GHz. Measurements were carried out to evaluate the impact on the coverage radius and the system capacity. Keywords—Capacity, Co-location, Coverage, Noise rise.

Over the past two years, there has been a massive public outcry over the deteriorating Quality of Service (QoS) in the operations of mobile cellular companies in Nigeria. One of the Key Performance Indices (KPI) for QoS monitoring is the drop call probability. Its minimization is the typical result of many optimization procedures applied to several service areas. The maximization of service coverage area and network usages, the minimization of interference and congestion, the optimum traffic balancing among the different frequency layers (900 MHz and 1,800 MHz in GSM standard) are some of the optimizing procedures used in minimizing drop call probability. This work presents the characterization of channels for the analysis of call drop probabilities in well-established cellular networks. The analysis is entirely statistical; all the data set to be fitted was provided by the Operation and Maintenance Center (OMC) of ZAIN Nigeria, a cellular network provider. An analytical model is de...

The tremendous loss of lives and properties that may be attributed to criminals in recent times worldwide has become a source of worry to all and sundry. The situation has come to the alarming rate that the authority has sought for the immediate means of checkmating it without delay. Therefore, this work centers on the design and implementation of an Internet Protocol (IP) based surveillance security system. It incorporates remote viewing and storage of live video feeds and also remote motion control of the camera, all monitored with the use of a Personal Computer (PC). All the designs in this paper are software based. Hence the software applications are developed using Visual C-Sharp (C#) programming language to enable the proper monitoring and control of the entire system in which video feeds from the camera are viewed and also recorded on PC. The result obtained showed that with proper implementation, the surveillance system was found to be superb in all its ramifications.

This paper presents statistical path loss models derived from experimental data collected in Port Harcourt in South-South region of Nigeria from 10 existing microcells operating at 876 MHz. The results of the measurements were used to develop path loss models for the urban (Category A) and the suburban (Category B) areas of Port Harcourt. The measurement results showed that the Pathloss increases by 35.5dB and 25.7dB per decade in the urban (Category A) and suburban (Category B) areas respectively. Variations in path loss between the measured and the predicted values from the Okumura-Hata model were calculated by finding the mean square errors (MSE) to be 10.7dB and 13.4dB for the urban and suburban terrains respectively. These variations (errors) were used to modify the Okumura-Hata models for the two terrain categories. Comparing the modified Hata model with the measured values for the two categories showed a better result. The developed statistical Pathloss models or the modified...