Analysis of co-channel interference in weak field area of high-speed railway

Co-channel interference is a key performance indicator of railway digital mobile communication system (RDMCS). Based on an overall consideration of both small-scale attenuation and large-scale attenuation, this paper analyzes co-channel interference in two typical scenarios of weak field areas where repeaters are utilized. In small-scale attenuation, we consider time delay difference. If time delay difference of signals with same content is too long, signals may not be equalized and then become reciprocal interference. In large-scale attenuation, we calculate the power of co-channel signals through transmitting power and path loss. Then we simulate the carrier-to-interference ratio (C/I) of co-channel interference. According to the requirements of high-speed railway, this paper proposes some schemes of transmission equipments´ location and distance to reduce the impact of co-channel interference. Because of some data and scenarios in this paper is from practical situation in China high-speed railway, these schemes are more coincidental with the reality, reasonable, practicability and useful for radio planning in new railway networks.