Analysis of handoff algorithm-based on Doppler effect and RSSI measurements in GSM-R network

Abstract

Compared with other kinds of networks, the mobiles in GSM for railway networks move faster, so the Doppler effect is more severe. A proposed handoff algorithm based on Doppler effect and RSSI measurements is evaluated. The algorithm performs handoff when the Doppler frequency shift value is negative and the measured signal strength of the adjacent base station exceeds that of the serving base station by a hysteresis level. The hysteresis level varies with different Doppler shift values. The average number of handoffs, average delay of handoffs, and average dropped calls are adopted as criteria for performance. Numerical results are presented to demonstrate the feasibility of the Doppler-effect-based algorithm. The proposed algorithm is compared with two other handoff algorithms. One is based on absolute and relative signal strength measurements; the other on hysteresis variable. It is found that the proposed handoff algorithm performs better than the other two handoff algorithms in log-normal fading environments.

Keywords:

• handoff
• doppler effect
• RSSI measurement
• GSM-R

Acknowledgement

This research was supported by the National Science and Technology Pillar Program of China under grants No. 2009 BAG12A08-07.