Embodiments herein provide methods and systems for achieving D2D communications through unlicensed spectrum. The D2D-U operations can be achieved through multiple approaches. In the first approach, the devices can communicate with each other without any involvement of network. In the second approach, the network provides partial assistance to the devices such as allocating time and frequency resources for D2D-U communication. In the third approach, the network completely controls D2D-U operations between the devices. The embodiments include allocating time and frequency resources for transmission of PSBCH, PSDCH, PSCCH, and PSSCH. The allocations of the time and frequency resources meet regulatory requirements of minimum bandwidth utilization for unlicensed band operation. The embodiments include distributing power in narrow frequency sub-bands of D2D-U spectrum, in order to maximize transmission range of D2D-U communications.