In this paper, we investigate the one-way relaying assisted secondary user information exchange, i.e., cognitive one-way relaying scheme, and the two-way relaying assisted secondary user information exchange, i.e., cognitive two-way relaying scheme, in cognitive radio networks. The exact closed-form expressions of outage probability for the proposed schemes are derived with imperfect spectrum sensing over Rayleigh fading channels. Considering the effect of the interference from the primary user on secondary data transmissions performance, we further give the closed-form expressions of outage probability floor. Numerical results show that the cognitive two-way relaying scheme outperforms the cognitive one-way relaying scheme in terms of outage probability performance.