Researches Related to Communication
Title: Weighted Multiple Linear Regression Model for Mobile Location Estimation in GSM Network
(by): Prof. Ani Cosmas (Ph.D), Dr. Longinus S. Ezema
Abstract: The numbers of crimes and accidents, among other challenging issues, requiring a mobile application with localization capabilities are on the increase. Yet there is under-utilization of location information provided by mobile phones. The accuracy and cost of implementation of mobile position localization on cellular network have been an issue of research interest. In this paper, the statistical modelling of mobile station (MS) position location was carried out using weighted multiple linear regressions (WMLR) method. The proposed statistical modelling approach was based on received signal strength (RSS) technique. The model improved localization accuracy. The model’s simulated results were analysed and compared with the existing MLR using real measured data collected from GSM network in a light urban environment in Enugu, Nigeria.
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Title: Design and Analysis of Voice and Critical Data Priority Queue (VCDPQ) Scheduler for Constrained-Bandwidth VoIP Networks
(by): Prof. Ani Cosmas (Ph.D), Dr Justice Dike (Ph.D)
Abstract: Voice over Internet Protocol (VoIP) networks are converged information superhighway systems for transporting multimedia traffics, such as: voice, video and data traffics. In the quest to optimize the Quality of Service (QoS) of these networks, many schemes have been proposed to address the needs of both real-time and non real-time traffic flows. In most of the schemes, low latency and packet loss to the streaming flows as well as fair resource utilization are guaranteed only if the rate of the real-time traffic flow is a small fraction of the link capacity. Again, earlier solutions to the QoS challenges of VoIP networks have been focused on giving precedence to voice traffic at the expense of time-sensitive business/mission critical data (B/MCD) traffics. This work therefore investigates the contributions of delay and packet loss impairment factors to the overall quality degradation of VoIP networks. It proposes an optimized voice and B/MCD fair and priority traffic scheduler for constrained-bandwidth VoIP networks. The scheduler incorporates mechanisms to achieve a graceful trade-off between priority and fairness to all traffics. Riverbed (OPNET) Modeler was used to validate the proposed architecture. Simulation results obtained show that the proposed architecture guarantees good mouth-to-ear delay and packet loss probability.
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Title: Improving Weighted Multiple Linear Regression Algorithm for Radiolocation Estimation in LoRaWAN
(by): Dr. Nwawelu Udora (Ph.D), Dr. Ahaneku Mamilus Aginwa (Ph.D)
Abstract: In location-based services, weighted multiple linear regression (WMLR) algorithm is used for radio device position estimation. Nevertheless, WMLR provides coarse location estimate, because weights apportioned to the received signal strength (RSS) for each hearable base station during matrix weight formation are not properly distributed. In an attempt to address the problem articulated above, an improved WMLR that enhanced the accuracy of radio device position estimate is proposed in this work. Min-Max scaling was used to determine the weight for each RSS values logged at different BS, as such forming a refined matrix weight. Public on-site outdoor long range wide area network (LoRaWAN) RSS data set was used to assess the improved WMLR estimation algorithm on the basis of accuracy. The location accuracy of the proposed method is validated with the existing WMLR algorithm and Federal Communication Commission (FCC) maximum location error benchmark. Results show that the location accuracy of the improved approach outperformed that of the existing WMLR localization method.
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Title: Novel Error Detection Scheme in Communication Network Based on Complete Polynomial Check
(by): Dr. Ahaneku Mamilus Aginwa (Ph.D), Dr. Vincent Chukwudi Chijindu (Ph.D), Dr. Udora Nwawelu (Ph.D), Engr Ezeja Michael Obinna, Chibuike C. Nwoye
Abstract: Many communication channels are subject to channel noise which may introduce error(s) during the process of transmission of frames from the transmitter to the receiver. These errors make the receiver not to properly decode the transmitted data. It is a known fact that the present error detection schemes are inefficient in error detection, as some may be good in detecting single bit error detection, while the others may be good in another type of error detection. For that reason, there is need fashioned a new error detection scheme that could correct the shortcoming of the present error detection schemes. Consequently, this study focuses on developing a new and more robust efficient error detection scheme. In line with the above objective, an error detection scheme was developed and the scheme was validated against CRC using MATLAB Simulink. From the simulation, the results show that the new error detection technique has 16 undetected error frames per 100,000 transmitted frames compared to 330 undetected error frames per 100,000 transmitted frames for CRC. The result also shows that the new error detection scheme reduces the number of the undetected erroneous frame by 93.6% when it is subjected to the same condition with CRC-8.
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Title: Improving Peak to Average Power Ratio of OFDM Signal Using DCT Pre-coding with Combined Distortion Techniques
(by): Engr. Bonaventure Onyeka Ekengwu, Engr. Nnaemeka Asiegbu, Chidieberu Nnaedozie Moghalu, Ifeoma Ezeanya
Abstract: This paper has presented Peak to Average Power Ratio (PAPR) reduction improvement in Orthorgonal Frequency Division Multiplexing (OFDM) system using discrete cosine transform (DCT) precoding with repeated clipping and filtering plus Mu-law companding techniques. Recent studies have shown the use of evolution algorithms and combination of two or more algorithms to reduce PAPR in OFDM system. The algorithms of DCT, RCF and Mu-law were studied and presented in form of mathematical equations. MATLAB codes were developed for PAPR analysis in OFDM system. The MATLAB codes for DCT, RCF and Mu-law companding were implemented and incorporated into the OFDM system to enhance the PAPR performance. Simulations were conducted considering uncoded (or conventional) OFDM, uncoded of OFDM with RCF, precoded of OFDM with RCF, and precoded OFDM with RCF plus Mu-law. Using the PAPR value of 10.43dB at CCDF of 10-3 for the uncoded OFDM signal as reference value, it was observed that the introduction of RCF into the uncoded OFDM provided a PAPR value of 6.834dB which is 34.48% improvement. Also, for the precoded OFDM with RCF, the PAPR was reduced to 6.799dB with 34.81% improvement. Finally, the proposed scheme using precoded OFDM with RCF and Mu-law provided an efficient reduction in PAPR with a value of 2.048dB and 80.36% improvement. Thus, the implemented scheme has shown to be effective based on MATLAB simulations conducted.
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