Device-to-Device (D2D) communication has proven as a candidate solution for offloading the data traffic and improving spectrum efficiency of cellular communication systems. It allows the terminals to communicate directly without increasing the load on the base station (BS). Underlay D2D is adopted in our work because it is more spectrum efficient due to channel sharing among cellular user (CU) and D2D pair. This kind of sharing is beneficial only when appropriate resource management is done otherwise it causes harmful interferences too. This work introduces an efficient and simple method to find multiple CUs as reuse partners for each D2D pair. After the selection of channels, power control is applied by means of convex optimization for D2D pairs to control the interference at the BS. The objective of the work is to maximize the D2D sum-rate without affecting CU's performance. The proposed scheme is then compared with existing pairing algorithms named as Hungarian also known as Kuhn-Munkres (KM) and IPPO algorithms and performance gain is verified through simulation results.