Device-to-Device (D2D) communication schemes have gained more attention in cellular networks particularly in normalization process of the upcoming 5G networks. They have been investigated in core network offloading, congestion reduction and channel usage optimization. The two last cases are among the major constraints in current cellular networks and are the main concerns of this paper. The paper presents a mixed mode D2D communication scheme to decentralize data collection between devices and the base station in order to reduce the number of direct connections at the base station of ultra-dense cells characterized by different levels of channel utilizations or target data rates, as expected for 5G networks. The attachment utility is derived as the overall gain of a device for a target data rate and is used as a metric for D2D association’s decision. Results show that the attachment utility and D2D pairs increase by either increasing the D2D communication range or decreasing devices’ target data rates. A further important consideration is that the proposed mixed mode D2D communication scheme improves the throughput expectation in the cell by 14.2% compared to the regular cellular communication