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Gebrehiwet Gebrekrstos Lema
Mekelle University

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A simulation based performance evaluation of optical ethernet switch Dawit Hadush Hailu; Gebrehiwet Gebrekrstos Lema; Gebremichael T. Tesfamariam; Tole Sutikno
Indonesian Journal of Electrical Engineering and Computer Science Vol 17, No 3: March 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v17.i3.pp1639-1646

Abstract

With the advent of several new cloud radio access network (C-RAN) technologies, today’s networking environment is dramatically altered and is experiencing a rapid transformation. One of the most important is ethernet based C-RAN, in support of which many products such as optical Ethernet switches have recently appeared on the market. This paper presents the performance analysis of such switches with respect to packet loss ratio (PLR), latency and packet delay variation (PDV). We employed the Simula based on discrete event modelling on Simula (DEMOS), a context class for discrete event simulation to simulate a cut-through optical ethernet switch under two types of traffics: high priority (HP) traffic and low priority (LP) traffic. In this way, the paper evaluates the optical Ethernet switch performance quantitatively. The results obtained from the simulator showed that the high quality of service was reflected on HP traffic and the low quality of service in LP traffic. Hence, HP traffic can be used for transporting radio over ethernet (RoE) traffic while LP traffic can used for transporting time insensitive application. It is also found that HP traffic experiences a PDV equals to the duration of maximum sized LP traffic in Optical Ethernet switch.
Practical understanding of the operating principle of digital communication systems Gebrehiwet Gebrekrstos Lema; Teklehaymanot Baweke Reda; Dawit Hailu; Tole Sutikno
Indonesian Journal of Electrical Engineering and Computer Science Vol 16, No 1: October 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v16.i1.pp299-310

Abstract

There are many students and researcher who doesn’t really understand the practical operating principle of digital communication system. Hence in this paper, the digital communication system is studied and simulated. In the system kit development text and audio inputs are taken and encrypted with different encryption techniques including additive cipher, multiplicative cipher and affine ciphers. The encrypted data is converted in to an 8-bit binary, channel encoded with distinct channel coding styles like linear block encoder, cyclic encoder and convolutional encoder, line coded and band pass modulated by different digital modulation techniques. Finally, the developed software is tested with equivalent inputs of the current national TV broadcasting and the results found are correct according to the theoretical analysis of the discussion.
Integrated hybrid optical networking for 5G access networks Dawit Hadush Hailu; Gebrehiwet Gebrekrstos Lema; Gebremichael T. Tesfamariam; Tole Sutikno
Indonesian Journal of Electrical Engineering and Computer Science Vol 17, No 3: March 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v17.i3.pp1647-1656

Abstract

Today, deployment of optical fiber has offered large transmission capacity which cannot be efficiently utilized by the electronic switches. Rather, Integrated Hybrid Optical Network (IHON) is a promising approach which combines both packet and circuit switching techniques. As a result, it achieves efficient utilization of the bulk capacity and guarantees absolute Quality of Service (QoS) by optimizing the advantages of the two switching schemes while diminishing their disadvantages. Transpacket has developed a Fusion node implementing IHON principles in Ethernet for the data plane. Hence, this paper investigates and evaluates IHON network for 5G access networks. The simulated results and numerical analysis confirm that the Packet Delay Variation (PDV), Delay and Packet Loss Ratio (PLR) of Guaranteed Service Transport. (GST) traffic in IHON network met the requirements of 5G mobile fronthaul using CPRI. The number of nodes in the network limits the maximum separation distance between Base Band Unit. (BBU) and Remote Radio Head (RRH), link length; for increasing the number of nodes, the link length decreases. In addition to this, we verified how the leftover capacity of fusion node can be used to carry the low priority packets and how the GST traffic can have deterministic characteristics on a single wavelength by delaying it with Fixed Delay Line (FDL). For example, for LSM1GE=0.3 the added Statistical Multiplexing (SM) traffic increases the 10GE wavelength utilization up to 89% without any losses and with SM PLR=1E−03 up to 92% utilization.
Performance evaluation of space time trellis coded MIMO for mobile communications Gebrehiwet Gebrekrstos Lema; Teklehaymanot Baweke Reda; Dawit Hailu; Tole Sutikno
Indonesian Journal of Electrical Engineering and Computer Science Vol 15, No 3: September 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v15.i3.pp1501-1508

Abstract

The major enemy of wireless communication is multipath fading that highly degrades the received signal. Spatial diversity highly reduces deep fades of the wireless communication. Higher signal to noise ratio (SNR) requirement can be reduced by using space time coding. In this paper, the error performance of un-coded MIMO, different diversity combing methods, space time block codes and space time trellis codes are analyzed using different parameters including number of antennas, M-array modulations, trace criteria, rank and determinant. The simulation results have shown that the Bit Error Rate (BER) significantly reduces with increasing number of receiver antennas. However, the number of antennas that a mobile device can have is limited by its size and this is inconvenient for mobile communication. Hence, this paper suggests space time codes to mitigate multipath problems in mobile communication. So, BER performance of space time block codes scheme was evaluated by varying the number of transmitter and receiver antennas along with varying M-array PSK modulation orders. The results have shown that better BER is possible by integrating space time codes with spatial diversity. Finally, the error performance of space time trellis codes was evaluated by using trace, rank and determinant, and the simulation results depicted that better error performance is achieved using the proposed multipath reduction method.
Co-Authors Dawit Hadush Hailu Dawit Hailu Dawit Hailu Gebremichael T. Tesfamariam Teklehaymanot Baweke Reda Tole Sutikno