In this paper, a cooperative spectrum sharing system is investigated. To effectively access the radio spectrum licensed to the primary users, the distributed cyclic delay diversity (dCDD) scheme is employed as the transmit diversity scheme for distributed cyclic-prefixed single carrier transmissions. As a setup for the secondary users' network, it is assumed that it comprises the control unit and a group of remote radio heads. In the secondary users' network, a single primary user transmitter is assumed to be located isotropically, so that a mixture of line-of-sight and non-line-of-sight paths over frequency selective fading channels is considered. One of the objectives of this paper is to investigate the effects of this new channel model on the outage probability probability promised by dCDD. A closed-form expression for the outage probability is derived first, and then its asymptotic expression is derived to characterize the maximum achievable diversity gain. Link-level simulations are also conducted to verify the performance analysis.