A new method for mitigation of mobility effect of SUN MR-OFDM in Fast Fading channel

As an advanced development of wireless sensor network which is defined by IEEE 802.15.4 specification, Low-power wide-area network (LPWAN) has considered the possibility of long range, low power, low cost, and mobility. The issue on mobility is covered from in IEEE 802.15.4g Standard to support a smart utility network (SUN) which is mainly commanded by the frequency division multiplexing of OFDM modulation. At the high mobility scenario, the Inter-carrier interference is one of main factors for reducing the performance of MR-OFDM transmissions due to the destruction of the orthogonality between subcarrier components. This paper analyzes the effects of high mobility in Multi-rate multi-regional orthogonal frequency division multiplexing (MR-OFDM) for low-power wide-area networks in general and the SUN MROFDM system in particular. With fast fading channel, the change of Doppler shift is very fast, which cause difficulties for estimating and compensating Carrier Frequency Offset. Other way, MR-OFDM is one of LPWA technologies then optimization problems of energy are its first priority. Simple technologies for high efficiency get our special interesting in MR-OFDM system. From that, we proposed a new method using the cyclic-prefix and the repetition code to mitigate Doppler shift in fast fading channel.