Cluster DRS: Enabling 5G for Low-Altitude Communication and Beyond

The “Cluster” concept has been jointly developed by China Telecom and ZTE since 2021. The cluster dynamic spectrum sharing (Cluster DSS) solution in the frequency domain improves user experience by enabling efficient 4G and 5G spectrum sharing, while the cluster dynamic frame sharing (Cluster DFS) solution in the time domain supports versatile 5G capabilities. By extending the “Cluster” concept to the spatial domain, the cluster dynamic radio sharing (Cluster DRS) solution enables low-altitude, three-dimensional coverage on 5G commercial networks, delivering ultra-stable user experiences and expanding across industries to fully unlock the potential of 5G.

The Cluster Concept

Traditional wireless networks, from 2G to 5G, typically rely on uniform resource allocation strategies, including spectrum usage, uplink/downlink time slot ratios, and inter-cell coordination methods (e.g., joint reception and transmission, handovers). While these uniform strategies offer benefits like simplified network management and reduced inter-cell interference, they can limit network flexibility and performance.

As 5G evolves, networks face diverse challenges, including increasing user demands, deeper integration with various industries, and the emergence of new scenarios. In this context, relying on a uniform service strategy limits the network's ability to adapt and scale to these diverse needs.

To overcome these challenges, China Telecom and ZTE introduced the “Cluster” concept. This approach groups base stations with similar service characteristics and requirements into clusters. Each cluster uses a tailored resource allocation strategy, while different clusters employ differentiated approaches. By adapting strategies to the specific needs of each cluster, the network enhances scalability and flexibility.

The “Cluster” concept optimizes network performance across frequency, time, and spatial domains, unlocking greater network value.

• Frequency domain: Cluster DSS improves 4G/5G spectrum sharing capabilities.
• Time domain: Cluster DFS accelerates the digital transformation of 5G fully-connected factories.
• Spatial domain: Cluster DRS facilitates the rapid growth of the low-altitude economy and expands to more 5G application scenarios.

These adaptive approaches allows the network to better meet the demands of evolving 5G applications and industries, ensuring sustained growth and efficiency.

Cluster DRS with Advanced Spatial Coordination for Low-Altitude Communication

As 5G commercial networks continue to scale, China Telecom has set its sights on the “ToX" domain, addressing emerging applications like the low-altitude economy and vehicle-to-everything (V2X). The low-altitude economy, a growing strategic sector worldwide, presents a new frontier for economic development. Drones are being increasingly deployed in key areas such as emergency response, logistics, agricultural protection, geological surveys, power grid inspections, and security patrols. As drone deployments scale up, critical requirements like HD video transmission and real-time control are becoming more urgent.

China Telecom's extensive, high-quality 5G network covers vast areas across the nation. As communication demands from low-altitude operations increase, extending this robust 5G infrastructure to cover low-altitude airspace becomes essential, specifically for real-time data transmission and wide-area connectivity.

However, the low-altitude airspace, with fewer physical obstacles, experiences more pronounced cell overlap than ground-level environments, leading to stronger inter-cell interference. This makes it challenging to ensure stable, real-time communication in low-altitude scenarios. To overcome these challenges, Cluster DRS was introduced, shifting the network architecture from a cell-centric to a user-centric model. By leveraging existing 5G commercial networks, Cluster DRS enables comprehensive three-dimensional coverage in low-altitude areas, addressing the specific needs of various industries.

Key Technical Principles of Cluster DRS  

Cluster DRS transforms traditional cell-centric resource management into a user-centric model. By leveraging the flight trajectory and service characteristics of drones, Cluster DRS enables deep resource coordination across multiple cells, dynamically centering around the drone. This ensures seamless service continuity and consistency, creating an efficient communication model that serves both low-altitude and ground users simultaneously. Fig. 1 provides an overview of the core innovations in the Cluster DRS solution.

Intelligent service perception and prediction: By integrating the base station's native intelligence with machine learning models like long short-term memory (LSTM), Cluster DRS can perceive and predict the flight paths and traffic patterns of drones. This allows for proactive resource allocation tailored to drone behavior, ensuring smooth and uninterrupted communication.

Drone-centric cluster formation: Cluster DRS dynamically generates a collaborative cluster of multiple base stations based on the drone's real-time flight trajectory and service requirements. This drone-centric cluster is adjusted based on the drone’s flight trajectory, providing continuous and seamless coverage for drone operations.

lDeep multi-cell coordination in the cluster: Within each drone-centric cluster, deep coordination among multiple base stations allows for optimized spatial beamforming. By sharing beamforming data, base stations can collectively adjust beam directions and power levels based on the drone’s movement and position. This creates highly efficient, directional communication links, significantly enhancing communication capacity, spectrum efficiency, and ensuring high-speed, stable data transmission.

Inter-cluster interference management: Cluster DRS employs intelligent inter-cluster interference mitigation strategies, minimizing interference between clusters. This ensures high-quality communication both among drones and between drones and ground users, maintaining network performance across the coverage area.

Through its innovative network architecture and intelligent scheduling strategies, Cluster DRS unlocks new communication capabilities for drone applications. It not only boosts communication efficiency and reduces operational costs but also injects new vitality into the drone industry, fostering its growth and expanding its potential applications.

Applications of Cluster DRS

Cluster DRS not only improves service reliability in drone operations but also accelerates the digital and intelligent transformation of the low-altitude economy, unlocking new possibilities for industrial applications.

Empowering Smart City Parks with Patrol Drones

In Century Park, Shanghai, which now operates under a 24/7 "open green space" policy, enhanced security and emergency response measures have become critical. To address these needs, the park has upgraded its smart surveillance system by introducing drone security patrols.

Overcoming the challenges of low-altitude communication, the innovative Cluster DRS solution enables real-time transmission of high-definition video from patrol drones. This extends the existing 5G coverage from ground level to an altitude of 300 meters, ensuring a stable uplink speed of 50 Mbps. By utilizing shared 5G network resources via a virtual private network, the system guarantees ultra-stable performance for drone operations.

Enhancing Security Inspections at Concerts

In Shaoxing, Cluster DRS was deployed to support low-altitude drone inspections during the Oxygen Music Festival, ensuring event security. Field tests demonstrated a 40%–50% reduction in drone handovers in low-altitude network environments, along with an approximately 30% increase in uplink speeds. This enabled the stable transmission of 4K ultra-HD video, ensuring reliable, real-time surveillance in low-altitude conditions.

These real-world applications highlight Cluster DRS as a critical enabler for stable and efficient drone communication, supporting a variety of industries and enhancing 5G potential in low-altitude scenarios.

Expanding Beyond Low-Altitude Communication

Initially developed to address the demands of low-altitude communication, Cluster DRS provides deterministic communication services for drones by ensuring reliable 5G connectivity and mitigating inter-cell interference. These challenges are not unique to low-altitude operations—they also persist in other domains. For example, autonomous driving in V2X networks requires dependable uplink HD video transmission and high-reliability control, while waterway communication increasingly demands ultra-HD video streaming. In all these scenarios, high cell overlap is a common issue, making Cluster DRS an ideal solution for improving waterway coverage and supporting various V2X applications.

Conclusion

The Cluster family of technologies, built on a foundation of base station intelligence, and enhanced by big data and advanced AI capabilities, seeks to strike an optimal balance between limited network resources and growing service demands. By precisely aligning requirements with resources in the spatial domain—based on user and service characteristics—Cluster DRS enables 5G networks to quickly adapt to emerging applications and scenarios, unlocking the full potential of 5G and facilitating its continuous evolution and expansion as new technologies and use cases emerge.