— In this paper, we present an O(1) time-complexity packet scheduling algorithm which we call G-3 that provides bounded end-to-end delay for fixed size packet networks. G-3 is built over two round-robin schedulers SRR [10] and RRR [7] and several novel data structures. In G-3, bounded delay is provided by evenly distributing the binary coded weight of a flow into a Square Weight Matrix (SWM) and several Perfect Weighted Binary Trees (PWBTs). In order to achieve O(1) time complexity, the SWM matrix is further spread by a Weight Spread Sequence (WSS) and each PWBT tree is spread by a corresponding Time-Slot Sequence (TSS), respectively. G-3 then performs packet scheduling by sequential scanning the WSS and TSS sequences. G-3 can be implemented in high-speed packet networks to provide bandwidth guarantee, fairness, and bounded delay due to its O(1) time complexity.