Shifting Paradigm to User-Centric 5G-A Networks: D³-ELAA

As 5G-A commercialization unfolds and the mobile AI era advances, emerging services and application scenarios are placing higher demands on user experience and differentiated service assurance. ZTE has introduced dynamic, distributed and deterministic-extremely large antenna array (D³-ELAA) technology, bringing core concepts such as 6G's "cell-free" into early application within 5G networks. This technology actively drives a shift from network-centric service strategies to a user experience-centric model, empowering a wider range of application scenarios and accelerating the continuous evolution of future networks.

5G-A Needs to Shift from "Cell-Centric" to "User-Centric"

Traditional mobile networks are designed around a cell-centric architecture, providing "best effort" service capabilities. This means that cell-center users enjoy optimal network performance, while cell-edge users often experience significant degradation due to path loss and interference from neighboring cells. As users move, their experience fluctuates noticeably, and handovers can lead to service interruptions, affecting service continuity and quality.

As 5G commercial networks scale up and the demand for new services, scenarios, and value continues to rise, the traditional cell-centric architecture is becoming increasingly inadequate to meet these evolving needs:

• Development of new business: With the rapid growth of 5G services, new applications such as glasses-free 3D, cloud computing, XR metaverse, and ultra-HD live streaming are becoming part of our daily lives. These emerging services demand higher, more stable uplink and downlink speeds, as well as low latency, to ensure a seamless and reliable experience.
• Expansion into new scenarios: The new era requires 5G-A networks to deeply integrate with various industries, supporting high-reliability, low-latency applications in sectors such as industrial manufacturing, mining, energy, steel, healthcare, and education. It also calls for the expansion of 5G-A into emerging scenarios like vehicle-to-everything (V2X) and low-altitude communications, where stringent deterministic network requirements for applications such as autonomous driving and remote control must be met.
• Extension of new value: 5G-A is not only a critical phase in the technical evolution of 5G networks but also plays a pivotal role in realizing the commercial potential of 5G. By leveraging 5G-native intelligence for precise user identification and accurate experience assurance, operators can introduce differentiated service packages that effectively increase average revenue per user (ARPU). For example, service packages tailored to specific use cases—such as live streaming, gaming, or guaranteed high-speed connectivity for high-speed rail users—can be engineered to meet distinct performance requirements. By integrating user experience metrics into service offerings, operators can further enhance ARPU while accelerating the full commercial potential of 5G-A, ensuring the network's long-term scalability and operational efficiency.

The development of new applications, scenarios, and value urgently requires 5G-A networks to shift from the traditional "cell-centric" model to a "user-centric" approach, enhancing the flexibility and robustness of the network to deliver consistent and superior service experiences anytime, anywhere.

Driving Massive MIMO Evolution with a User-Centric Approach

Enhancing network performance has always been a key pursuit in mobile communications. Looking back at the 4G era, the introduction of multiple-input multiple-output (MIMO) technology significantly boosted network capacity and performance. During the Pre5G phase, ZTE introduced Massive MIMO, which allowed more users to be served simultaneously on the same time-frequency resources. This technology dramatically improved beamforming gain, spatial multiplexing gain, and spatial diversity gain, leading to a substantial increase in spectrum efficiency and laying a solid foundation for 5G's high performance.

In 5G-Advanced, Massive MIMO technology needs to evolve towards a higher system performance. From a theoretical perspective, increasing the number of transmit and receive antennas on both the base station and user device sides is a key method to further enhance spectral efficiency and unlock the full potential of Massive MIMO. However, for the already deployed 5G commercial networks, operators are more focused on improving the capabilities and performance of Massive MIMO based on existing networks and equipment, ensuring a smooth and efficient upgrade.

As a result, ZTE has integrated the user-centric approach into the evolution of Massive MIMO, creating the D³-ELAA solution. By dynamically adjusting network coverage based on the user's location, this solution ensures that users are always at the center of network coverage, thereby significantly enhancing the overall user experience.

Key Technologies of D³-ELAA

The D³-ELAA solution employs a distributed base station architecture and dynamic networking to create an extremely large antenna array, ensuring a deterministic user experience. This innovative approach overcomes the constraints of traditional cellular architectures, enabling the network to deliver ultra-stable, high-performance user experiences (Fig. 1).

Dynamic: Forming User-Specific Clusters with RAN-Native AI

In traditional mobile communication networks, resource allocation strategies are typically based on service types. However, transitioning to a user-centric service model complicates resource management. To address this, ZTE leverages  RAN-native AI to dynamically optimize resource allocation.

By applying machine learning, the network can analyze historical data and trends to gain deeper insights into user service demands and predict mobility patterns. Based on these predictions, the network dynamically forms personalized, cooperative cell clusters tailored to each user, ensuring they remain at the center of the service cluster at all times.

Furthermore, by continuously forecasting user mobility in real-time, the network can proactively adjust the structure of these clusters, ensuring a seamless and stable service experience as users move across the network. This enhances the network’s ability to deliver optimized, uninterrupted connectivity.

Distributed Massive MIMO: Enhancing Network Service Capabilities

Multiple base stations within a user’s service cluster can collaborate to further enhance the user experience. While various cooperation methods (such as coordinated scheduling and joint transmission) are already used in the industry, these primarily focus on reducing or eliminating inter-base station interference. The D³-ELAA solution goes a step further by improving time synchronization accuracy between base stations from the microsecond to the picosecond level and incorporating user-level joint beamforming algorithms, enabling multiple base stations within the user’s cluster to perform joint beamforming. The distributed deployment of these base stations effectively forms a larger-scale antenna array, resulting in significant gains in power, channel count, and beamforming flexibility, translating into a remarkable improvement in user experience.

Deterministic Experience Improved

By forming user-centric clusters and enabling coordinated collaboration within them, the D³-ELAA solution greatly improves the user service experience. This is particularly beneficial for users at the cell edge, where issues like edge interference and frequent handovers—common causes of service interruptions—are effectively mitigated. As a result, the user experience is significantly enhanced, and the network’s ability to provide deterministic service assurance is strengthened.

ELAA: Surpassing Single-Device Capabilities

The D³-ELAA solution leverages existing 5G commercial equipment to create a much larger antenna array. At the cell edge, users typically receive signals from two or more neighboring cells, with relatively stable signal strength. In such cases, D³-ELAA employs joint beamforming technology, allowing geographically dispersed base stations to combine and create an ELAA. For instance, in overlapping coverage areas, three individual 64T64R cells can be combined to form a 192TR service array, delivering a significantly enhanced service experience. This extremely large antenna array surpasses the limitations of individual equipment, striking an optimal balance between performance and cost.

D³-ELAA: Pioneering a Zero-Fluctuation Mobile Experience

"Plug-and-Play" for 5G Commercial Networks

The D³-ELAA solution brings the user-centric concept of 6G into commercial 5G networks. From the initial design phase, full consideration was given to ensuring compatibility with existing 5G commercial systems and equipment. By enhancing the intelligent computing and coordination capabilities of radio equipment, D³-ELAA seamlessly adapts to current 5G commercial networks and is fully compatible with commercial devices, requiring no terminal upgrades or replacements. Users can immediately experience significant improvements brought by the system upgrade.

Reduce Interference, Enable "Upgrade Action"

Wuhan Institute of Technology has completed comprehensive 5G coverage; however,  network interference in some overlapping 5G coverage areas affects user experience. In line with the Ministry of Industry and Information Technology's "Upgrade Action" initiative, D³-ELAA was commercially validated on campus. Following its introduction, network speeds in areas such as the student cafeteria, research center, and dormitories increased by up to six times, delivering a "full signal everywhere" experience to users.

Enhanced User Experience, Supporting New 5G Packages

Thailand's AIS has launched a range of new service packages, including high-performance plans with enhanced speeds, gaming packages tailored for gamers, and live-streaming packages designed for content creators. These packages aim to provide more personalized service experiences based on specific user needs. Commercial validation of D³-ELAA at Suranaree University of Technology (SUT) demonstrated a 2.3-fold overall average experience improvement during user mobility, with a performance increase of over sevenfold at cell edges. This ensures  lag-free cloud gaming and smooth high-definition video streaming, even during user movement, delivering an exceptional high-bandwidth service experience.

Over the past five years, 5G has generated significant commercial value and social benefits. With the commercialization of 5G-A and the advent of the mobile AI era, new services and application scenarios are emerging, placing higher demands on user experience and differentiated service assurance. D³-ELAA, built on innovative service concepts, enhances spatial coordination capabilities to ensure users enjoy stable and continuous network connectivity during mobility.

ZTE will continue to integrate and strengthen the user-centric approach across various dimensions, empowering wireless resources with enhanced coordination capabilities to drive higher-quality experience assurance and support the continuous upgrades and evolution of future communications.