The effect of fast relay fading and frequency mismatch of the frequencies of the receiving and transmitting channels on the characteristics of the OFDM signal

Abstract

In this paper, we consider the negative simultaneous effect of fast relay fading in the channel and mutual frequency shifts of subcarriers between the transmitting and receiving sides of the channel, causing violation of orthogonality between the signals of individual subchannels of OFDM system. Violation of orthogonality is manifested in the appearance of mutual interference signal at the receiving end of the channel in each OFDM subchannel. The paper evaluates the joint effect of fast fading and frequency shifts on the magnitude of the transient interference between subchannels and investigates in sufficient detail the manifestation of transient interference between individual subchannels caused by orthogonality violations each of the two factors cited separately. In this paper, we consider the simultaneous effect of both factors and their influence on the value of the interchannel transient interference.

Keywords

• wireless communication systems
• carrier frequence offset
• fast rayleigh fading
• doppler speading
• inter-channel interference