Cosmas Kemdirin Agubor

Work place: Federal University of Technology, Owerri, Nigeria bThe First Technical University, Ibadan, Oyo State, Nigeria

E-mail: cosmas.agubor@futo.edu.ng

Website:

Research Interests: Wireless Communication, Antenna Technology

Biography

Cosmas Kemdirim Agubor has obtained B.Eng, M.Eng and PhD degrees. He is a registered member of the Nigerian Society of Engineers (NSE) and the Council for the Regulation of Engineering in Nigeria (COREN).He was an Engineer with the Nigerian Telecommunications Limited (NITEL) and rose to the rank of an Assistant Manager. He is now a lecturer in the Department of Electrical and Electronic Engineering, Federal University of Technology, Owerri, Imo State, Nigeria. His research area is in wireless communication with special interest in Antenna systems and diversity

Author Articles
Interference Mitigation in Wireless Communication – A Tutorial on Spread Spectrum Technology

By Cosmas Kemisdrin Agubor Akinyinka Olukunle Akande Reginald Opara

DOI: https://doi.org/10.5815/ijwmt.2021.05.04, Pub. Date: 8 Oct. 2021

This paper focuses on Spread Spectrum technique and its interference mitigation feature as applied in wireless communication. With spread spectrum technology it is possible to implement the transmission of multiple signals over wider ranges of spectrum without resulting to interference from other signals transmitted over the same frequencies. It does this by rejecting any received signal that does not carry the proper code. Interference rejection, one of the several features of spread spectrum technology is a difficult concept to understand. It is therefore proper to x-ray this topic in a less complex manner so that it can be well understood by those who are not mathematically grounded.   In view of this a further simplified approach in presenting this subject is necessary. A tutorial approach is used to simplify this subject for better understanding and how this feature is used in Code Division Multiple Access (CDMA) systems. To show how multipath interference rejection is achieved in CDMA systems simple equations and schematics were used. The discussions cover the method of code recognition at the receiver which serves as a technique for interference mitigation. The paper helps to understand the theory of code recognition in Spread Spectrum, and thus provides answer to the question on how does interference mitigation or rejection in spread spectrum works? 

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Development of a New Diversity Scheme in 5G Network at 28 GHz Millimter-wave Frequency for Digital Mobile System

By Akinyinka Olukunle Akande Cosmas Kemisdrin Agubor Olusola Kunle Akinde Longinus Sunday Ezema Samuel Okechukwu Okozi

DOI: https://doi.org/10.5815/ijwmt.2021.01.05, Pub. Date: 8 Feb. 2021

This paper presents an improved hybrid Equal Gain Combiner-Maximal Ratio Combiner (EGC-MRC) diversity scheme in 5G millimeter wave (mm-wave) frequency. The term 5G mm-wave refers to the radio frequency spectrum between 24 GHz and 100 GHz. The signal interference is a challenging task in 5G mm-wave frequency, and radio network suffer from co-channel and adjacent channel interference. 5G network deployment depends on large number of antennas, which resulted in signal interference. The conventional receiver’s diversity techniques have high hardware complexity and are characterized by low performance. A new hybrid EGC-MRC diversity scheme was proposed as an improvement on the performance of existing MRC scheme. In achieving this, Probability Density Function (PDF) of the hybrid model was derived using the instantaneous Signal-to- Noise Ratio (SNR) obtained from the output of MRC and EGC diversity schemes. The performance of the developed model was evaluated using Outage Probability 〖(P〗_out) and Processing time (P_t)  at different SNR with L number of paths. Simulation of the MRC, EGC and hybrid EGC-MRC models were carried out using MATLAB 2018a and the results compared. The output results showed that hybrid EGC-MRC performed better than EGC and MRC by having a lower P_out   and〖 P〗_t. This new model has the potential to mitigate network interference, multipath propagation, and hardware complexity in 5G mm-wave frequency. Therefore, the developed model can be deployed by network operators to solve signal interference in 5G network.

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