Simplified, Efficient, and Intelligent User Plane Design for 6G

6G wireless networks are expected to surpass 5G in key performance indicators such as latency, peak data rates, and connection density. However, unlike the focus on new spectrum and physical layer technologies, a lack of evolution in the network's structural architecture will lead to severe processing bottlenecks. The user plane is the most critical component determining user data delivery efficiency, power consumption of base stations and mobile devices, and network adaptability to diverse service requirements.

Limitations of the 5G User Plane

The user plane architectures of 4G and 5G are characterized by rigid hierarchical protocol stacks such as SDAP, PDCP, RLC, and MAC, along with reactive mechanisms. While suitable for mobile broadband, these structures fail to meet the stringent latency, energy, and processing requirements of 6G services like immersive communications and ultra-reliable autonomous systems. Extending the existing stack results in significant overhead, redundant processing stages, and high computational energy costs.

The 5G user plane experiences throughput bottlenecks and latency spikes when handling high-density real-time traffic due to rigid frame structures and header overhead. Additionally, it fails to dynamically adapt to URLLC (Ultra-Reliable Low-Latency Communications) requirements during network congestion, relying instead on a reactive model that triggers recovery procedures only after performance degradation has occurred.

Direction of the 6G User Plane

The 6G user plane will undergo a paradigm shift toward simplification, efficiency, and intelligence. Current 3GPP standardization efforts are moving toward a new user plane paradigm that manages the extreme traffic demands of 6G while adhering to the strict energy and processing constraints of future wireless ecosystems. This pursuit of an integrated and efficient design reflects lessons learned from 5G, such as delays in feature introduction, architectural overload, and fragmented strategy development.