Abstract—Internet of Things (IoT) operators tend to utilize smartphones in establishing reliable and sustainable communication links for their services. Collaborative IoT (CIoT) is a concept where the smartphones are utilized as a mobile gateway (GW) that connects sensors to the cloud. CIoT scheme has many challenges including the redundancy in transmissions of sensor readings. As the same sensor data is sent by many uncoordinated users, this leads to consuming network resources and degrading Quality of Services (QoS) for primary users. This paper has three main contributions: First, four metrics for evaluating redundancy and its effects in CIoT network are defined and explained. Second, a novel redundancy control scheme (Fresh-List redundancy control) is proposed and evaluated against well-known probabilistic transmission schemes using the proposed metrics. Finally, a simulation setup for CIoT environment is implemented using a computer equipped with Bluetooth network card. The setup simulates many CIoT users with different scenarios of random entry, departure, and dwelling times. Results show the ability of Fresh-List method to reduce redundancy order and increase efficiency compared to non-controlled redundancy. It is also shown that a mix between probabilistic transmission and Fresh-List methods provide even more better redundancy control at an acceptable increase at the average packet delivery delay.