Self-organizing OFDMA systems by random frequency hopping

Abstract

This paper analyzes the use of Random Frequency Hopping to enable self-organizing Orthogonal Frequency Division Multiple Access systems (RFH-OFDMA). While LTE (Long Term Evolution) macrocell resource planning is typically based on centralized planning of orthogonal deterministic frequency hopping patterns, the integration of femtocells located within macrocells introduces either complex planning efforts or uncontrolled interference issues. The results presented in this paper show that random frequency hopping is a new effective way to reduce interference for the integration of femtocells without resource planning into macrocells. An analytical model for the SINR (Signal-to-Interference-and-Noise Ratio) and a simulation model for the BER (Bit Error Rate) are presented for interfering RFH-OFDMA systems. All OFDMA parameters can be freely selected in time and frequency in the model, enabling to dimension systems with minimal interference. Based on the analytical model, a performance evaluation is presented, which uses typical LTE parameters. Compared to the performance of systems without resource planning and random frequency hopping, a significant gain is achieved for self-organizing RFH-OFDMA systems with respect to the SINR and BER.