Analysis of LTE-M Adjacent Channel Interference in Rail Transit

Area of Science:

• Telecommunications Engineering
• Wireless Communication Systems
• Railway Communication Networks

Background:

• Long Term Evolution-Metro (LTE-M) is crucial for train control, demanding robust resistance to adjacent channel interference (ACI).
• Existing subway communication systems require specific isolation degrees to mitigate ACI according to 3GPP/ETSI standards.

Purpose of the Study:

• To determine the necessary isolation degree for LTE-M systems to effectively combat ACI.
• To analyze ACI in subway environments, considering both underground (leaky cable, antenna transmission) and ground scenarios.
• To evaluate throughput loss in LTE-M systems due to coexisting cellular systems.

Main Methods:

• Deduction of isolation degree requirements based on channel characteristics and ACI principles.
• Monte-Carlo (MC) simulations to model coexistence scenarios between LTE-M and adjacent cellular systems in subway environments.
• Estimation of LTE-M system throughput loss using Signal-to-Interference-plus-Noise Ratio (SINR) analysis.

Main Results:

• Underground LTE-M systems using leaky cable radiation patterns show negligible interference from adjacent frequency user equipment (UE).
• For ground-based LTE-M systems, adjacent frequency UE poses the primary interference threat to the LTE-M base station (BS).
• Simulation results quantify throughput losses under various interference conditions.

Conclusions:

• Specific isolation degrees are essential for LTE-M deployment in rail transit to manage ACI.
• Interference mitigation strategies are vital, particularly for ground-based LTE-M systems in subway environments.
• The study provides valuable insights for designing and deploying reliable LTE-M communication systems in rail transit.