2019 Volume 23 Issue 3 Pages 83-93
This paper proposes an adaptive modulation (AM) and a transmit power control (TPC) on frequency symbol spreading (FSS) based orthogonal frequency division multiplexing (OFDM) relay system with considering the mobility of relay node. Wireless communications often suffer from large propagation loss due to shadowing and multipath fading. As a solution to this problem, relay communications, which forward data messages from a source to a destination via intermediate station(s), have been focused on. It can obtain the space diversity and expand the area coverage. In the situation where relay node has mobility, propagation channel fluctuates and communication quality is deteriorated. This paper presents a whole system design of FSS-OFDM employing AM and TPC. Exploiting a good match of AM and FSS, throughput performance can be significantly improved even in high mobility environment. In addition to this, utilizing TPC, the most suitable AM is enabled and leads to a further performance enhancement. Computer simulation verifies its effectiveness and reveals the proposed system is the most valuable means which realizes the flexible relay node deployment.
