Backscatter communications is rapidly evolving with each passing year. Due to a great amount of research interest in this technology, backscatter communications have found its application in healthcare, intelligent transportation systems, industrial automation, and supply management. Moreover, it is considered as one of the most promising technology for enabling massive and low-powered Internet of Things (IoT). Due to such revolutionary and transformative characteristics of backscatter communications, it is extensively used in radio frequency identification (RFID) systems. The performance of backscatter RFID systems is notably characterized by the overall system throughput. Since the next generation IoT networks are expected to have high data rate requirements, the conventional backscatter RFID systems may not be feasible. It is because the conventional system can only make use of slots with a single backscatter tag response and the data from the slots with multiple backscatter tag responses (collision slots) is discarded. Thus, the collision slots present in the system decrease not only the overall throughput but also increase the inventory time required for the system. To overcome this issue, this work combines frequency division multiple access (FDMA) and time division multiple access (TDMA) techniques. Specifically, a multi-tone carrier is exploited to recover the signal from multiple backscatter tags in collision slots. The numerical results indicate that the performance in terms of the expected throughput is significantly improved. These results can pave the way for high data rate IoT networks that use multi-tone backscatter communications.