OFDM performance analysis in the phase noise arising from the hot-carrier effect

Phase noise can be regarded as the most severe cause of performance degradation in the orthogonal frequency multiplexing division (OFDM) systems. The hot-carriers (HCs), found in the CMOS synchronization circuits, are the high-energy charge carriers that degrade the MOSFET devices performance by increasing the threshold voltage required to operate the MOSFETs. The HC effect manifests itself as the phase noise whose level increases with the continued MOSFET operation and results in the performance degradation of the voltage-controlled oscillator (VCO) built on the MOSFETs. Nowadays, the HC effect is particularly evident in the short-channel MOSFET devices. Consequently, the MOSFET instability due to this effect leads to the OFDM system performance degradation. In this paper, we analyze the OFDM performance in the presence of synchronization errors induced by the hot-carrier effect. We derive the relationship between the OFDM system performance and the hot-carrier effect in terms of a crucial parameter, the MOSFET threshold voltage. We also present a new general phase noise model for the OFDM systems influenced by the hot-carrier effect, which is based on our new phase noise mask function. According to our simulations, we show that the OFDM bit-error-rate evaluation using our new phase noise model in the presence of the HC effect can be different in three orders-of-magnitude from the existing models independent of the HC