Educational Emulation of a Soft Handoff Teaching Model (EESH-TM)

Abstract

The use of fixed Base and Mobile Stations offer a set of challenges dealing with the movement of a Mobile Station away from one Base Station toward a second Base Station. In this situation, the signal strength decreases as the distance of the mobile position increases (following an inverse-square law) from the first station; while an increase in signal strength is experienced as the distance decreases from the second one. Gradually the signal from the former is lost. This is a difficult problem in wireless technology, not only to picture but also to solve. This problem which is prominent in mobile and wireless applications is called ”Soft Handoff”, the solution of which applies the concept of ”make-before-break”, which postulates the smooth and gradual transition of signals from the previous Base Station to the next one without causing a sharp break or interruption of the signal. Such a hypothetically smooth and soft hand over signal mechanism is very difficult for students to understand especially those who have had little or no experience with telecommunication equipment, with the analysis of wireless circuits or with hands-on experience with the technology. This became evident when the topic was initially covered in a Telecommunications course at University of Namibia. It was within this context that the Educational Emulation of Soft Handoff Teaching Model (EESH-TM) was designed and developed to model the mechanism of Soft Handoff. The EESH-TM is comprised of: two Base Stations, two Cells, a Mobile Station, and two interacting signals. This teaching model clearly demonstrated, step-by-step, various scenarios with a mobile unit moving between two Base Stations clearly illustrating how Soft Handoff works. Hence, the utilization of this teaching tool presented inexperienced students with an opportunity to observe and understand how signal hand off works in a wireless network. The success of the model was demonstrated by higher examination scores and greater student interest in the topic.