Volume 29, Issue 2, February 2015

SFN Monitoring for DVB-T/T2 Networks [Full Text]

Todor Manev

Abstract—This paper is about finding a way to locate any problems in DVB-T/T2 Single Frequency Networks in a fast and effective manner. The most common problem in SFN networks is lost synchronization which can be caused by defective DVB-T transmitter, network distribution problems or a faulty GPS receiver at the transmitter site. All these problems lead to an asynchronous transmission causing reduced quality of reception up to the point of total interference. 


Error Correction Scheme for Wireless Sensor Networks [Full Text]

Abdulkareem A. Kadhim, Aya K. Al-Joudi, and Hamed Al-Raweshidy

Abstract— Wireless Sensor Networks (WSNs) have gained high importance in recent years. Because they are very small and can easily be implemented in any place, they invoke a wide range of applications. In the last years, improvements of wireless sensor networks have been made by applying Error Control Coding (ECC) schemes. Usually two different error control schemes are used for WSNs which are Forward Error Correction (FEC) and Automatic Repeat on reQuest (ARQ). These codes work either separately or in a hybrid manner known as Hybrid Automatic Repeat on reQuest (HARQ) schemes. A proposed coding arrangement is presented here and tested, aiming to provide further performance improvement for different applications of WSNs. The arrangement is based on HARQ scheme which consists of two concatenated FEC codes together with ARQ. The concatenation here reduces errors and hence unnecessary retransmissions by ARQ are avoided, thus energy saving is obtained. WSN simulator is built and used to test the proposed coding arrangement performance. The pro- posed coding arrangement shows better error rate performance when tested over models of AWGN, flat fading and multipath fading chan- nels. Improvements were gained also in throughput (packets/s) and energy saving as compared to other coding schemes normally used with WSNs. 


Automated Teaching Step-by-Step the Operations of TCP/IP Model (A-Step-TPC/IP) [Full Text]

Jameson Mbale and Mali Orient

Abstract— In the telecommunication industry, the operations of TCP/IP protocols play an instrumental row in the transmission of information in the form of packets or frames from one network to another. To start with, at the source host, a transmittable message was composed and passed through the various protocol layers where headers, such as TCP, IP and network were added or attached. Whereas, at the receiving host, the same headers were consequently removed until only the original mes- sage reached the destination. Such a process was absolute to visualise by the students for they did not tangibly see the mecha- nism involved. It was in view of that the Automated Teaching Step-by-Step the Operation of TCP/IP Model, in this work abbrevi- ated as ‘A-Step-TCP/IP’, was conceived to simplify the understanding of the concepts involved in this operation. An experiment in form of a test was done, by dividing a class into two groups. The Control Group which did not use the model as teaching aid had fifty three point three three percent (53.33%) failure rate. For the Regular Group, all the students had hundred percent (100%) passing rate. Such results proved the effectiveness of the model. 


Study of UWB On-Body Radio Channel for Ectomorph, Mesomorph, and Endomorph Body Types [Full Text]

Mohammad Monirujjaman Khan, Ratil Hasnat Ashique, and Md. Raqibull Hasan

Abstract—The effects of different human body sizes and shapes on the ultra wideband (3-10 GHz) on-body radio propagation channels are investigated. In this paper, three different human body sizes (Ectomorph, mesomorph and endomorph) are investigated. Experimental investigation is performed using a pair of Tapered Slot Antennas (TSA) in the indoor environment. Thirty four different receiver locations on the front part of the human body are considered for calculating the path loss. Results and analysis show that due to three different types of human body shapes and sizes maximum of 31.8% variation in path loss exponent is observed. The effect of the three different human body sizes and shapes variations on the 8 different ultra wideband on-body radio channels was also studied.