Spreading Sequence Design for Partially and Fully Connected AF Relay Networks under Multipath Fading

Multipath fading degrades the performance of wireless communication system significantly as data rate increases. In-order to combat with multipath fading, orthogonal frequency division multiplexing (OFDM) have been used in existing systems. Another effective method is a code division multiple access (CDMA) scheme. It has used extensively for relay network communication systems. In this paper consists of uplink CDMA relay networks and downlink CDMA relay networks. The uplink CDMA relay networks consist of multiple sources, multiple relays and a single destination. In downlink CDMA relay networks consist of a single source, multiple relays and multiple destinations. The objective of the paper is to propose a unique, simple method of finding optimum non-binary pseudo noise (PN) spreading and de-spreading sequences. This employs maximum signal to interference plus noise ratio (SINR) criterion and channel state information (CSI).