4G is a promising solution for the future mobile Internet through integrating heterogeneous radio access technologies (RATs) based on the Internet Protocol (IP) where multi-standard wireless devices allow mobile users to experience ubiquitous connectivity by roaming across different networks and connecting through the RAT that best suits their traffic requirements. However, holding multiple active interfaces incurs significant power consumption to the wireless devices. This necessitates investigating disruptive techniques for decreasing the power consumption of the 4G wireless devices. In this paper, we demonstrate how cognitive radio and cooperative communication can be integrated in 4G networks to conduct wireless devices to either perform vertical handover or execute relaying by exploiting their available short range interfaces (e.g., WiMedia, Bluetooth, etc) to reduce their power consumption while still enabling the required QoS. Simulation and experimental results validate that 4G wireless devices can double their battery lifetime by adopting the proposed strategies.