A control scheme using packet headers allows GSM EDGE Radio Access Network (GERAN) systems to increase spectral efficiency through multiplexing techniques, such as superposition coding, multi-user packet transmission, joint detection, and/or joint decoding. A fast feedback scheme for GERAN allows Voice over Internet Protocol (VoIP) frames to be transmitted over GERAN air interfaces without excessive feedback latency. As a result, Hybrid Automatic Repeat-reQuest (H-ARQ) acknowledgements may be timely provided for end-to-end VoIP calls that traverse GERAN air interfaces. Additionally, Incremental Redundancy H-ARQ and link quality feedback latencies are decreased.