It is well accepted that the 4G wireless network architecture will include different wireless access networks, glued together by Mobile 1P to provide seamless Internet access to mobile users. A major challenge in establishing such a heterogeneous architecture is QoS provisioning in different wireless networks. QoS provisioning is more complex in a CDMA cellular system due to the interference-limited capacity. In this article we propose a vertically coupled protocol architecture to provide QoS in 4G CDMA cellular networks. This architecture combines the transport layer protocols and link layer resource allocation to both guarantee the high-layer QoS requirements and achieve efficient resource utilization in the low layer. A packet-switching MAC scheme is also provided to achieve efficient multiplexing. The MAC scheduler uses only per-flow information in packet scheduling, thus significantly reducing the computation complexity and system overhead.