Randomized cyclic delay code for cooperative communication system

Abstract

In this thesis, we study problem of achieving the diversity gain for cooperative communication systems. We introduce randomized strategies that decentralize the transmission code from a set of distributed relays and their performance. The proposed method enable the relays to act independently and to achieve diversity gains in fully decentralized fashion. The simple idea we propose is to use cyclic delay diversity scheme with random delay at each node. The proposed methods are considered under a decode-select and forward relaying protocol and an amplify and forward relaying protocol. We show that the proposed scheme achieve the maximum diversity gain if SNR< $infty$ and N -> $infty$, where N is the number of subcarriers and the SNR is signal to noise ratio.