5G networks operate on multiple frequency bands, including low, mid, and high-band, with each band having different capacity and coverage characteristics. As the number of user equipment (UE) connected to the 5G network grows, the network must adapt to accommodate their diverse needs. While the majority of devices on 5G networks are personal devices like cell phones, more businesses and industrial applications are also utilizing these networks.
Each user and device has distinct demands that evolve constantly throughout the day. For instance, a person may require different services while walking their dog early in the morning, during rush hour, and at night. As people and traffic change, the network must respond rapidly and seamlessly by reallocating resources to satisfy the needs of different users and devices.
To achieve this, Ericsson’s new radio (NR) Multi-Layer Coordination solution coordinates the network deployment, cell configurations, UE capabilities, and cell load to optimize the network for the services used. In essence, 5G networks use traffic steering to optimize spectrum assets and provide a satisfactory user experience.
What is Traffic Steering?
Traffic steering involves shifting a device between different frequency layers within a specific geographic area to achieve a specific objective, typically maximizing user throughput. It may also serve other objectives, such as enabling a particular service that is only available through certain carriers.
In contrast, mobility pertains to maintaining device connectivity, preventing dropped calls, and ensuring continuous coverage while moving across different geographic areas, such as walking a dog while on a phone call. Traffic steering optimizes the user experience in such scenarios.
Notably, traffic steering is a vendor-specific solution without any standardization defined by the Third Generation Partnership Project (3GPP), allowing vendors to employ creative techniques to enhance the user experience. While traffic steering is present in 4G networks, its implementation in 5G is more intricate, driven by several factors.
5G standalone (SA) networks offer higher speeds, lower latency, and greater reliability than their non-standalone counterparts. However, the full potential of 5G SA can only be realized with advanced traffic steering capabilities.
How can advanced traffic steering improve network performance and user experience?
Essentially, advanced traffic steering allows the network to dynamically allocate radio resources to different users and applications based on their specific needs. This is done by using intelligent algorithms that take into account various factors such as network congestion, user location, and application requirements. For instance, it can be used to prioritize critical applications such as emergency services, or to ensure that high-bandwidth applications like video streaming receive the necessary resources to provide a smooth viewing experience.
The Complications of Advanced Traffic Steering
Optimizing 5G network performance and spectrum utilization is complicated due to the diversity of cells, devices, and services. The frequency bands in 5G networks are diverse, making it necessary to select the most appropriate cells for each user equipment (UE) based on multiple cells or sets of cells. Additionally, UEs and services have different requirements, with some needing higher capacity and throughput while others prioritize low latency and energy consumption.
The rise of Fixed Wireless Access and emerging technologies like augmented and virtual reality further complicates matters. Carrier aggregation allows for combining primary and secondary cells to increase capacity or coverage. However, finding the best UE configuration for each network deployment can be complex due to the many possible combinations. Load distribution is also important to ensure balanced cell utilization and improve device throughput. Ultimately, flexible and agile traffic steering is necessary to address the constantly changing needs of 5G networks.
Ericsson’s Traffic Steering Solution
Ericsson’s solution, called NR Multi-Layer Coordination for 5G Standalone (SA), will be used to address the complexities of 5G networks as discussed earlier. The solution includes an advanced Traffic Steering function that optimizes network performance and spectrum utilization. It is built upon an advanced selection algorithm that considers input parameters and optimization objectives to deliver the best possible UE configuration. The process involves three steps:
Step 1: Initial Input Parameters
The solution considers four initial input parameters – UE capabilities, UE group, network topology, and load. Coverage information is also considered where possible to exclude cells that are not in coverage. With the Ericsson framework, communications service providers (CSPs) can define different UE groups. They can also apply different traffic steering behaviors to observe the results of each group. For instance, they can specify which frequencies a device is allowed to use for different services such as FWA or Voice over NR.
Step 2: Optimization Objective
The selection algorithm quickly selects a cell set (PCell and one or more SCell(s)) that maximizes the optimization objective. The algorithm strikes a balance between speed and precision to offer the best outcome, considering the complexity of the vast number of possible combinations of frequencies and cells to choose from. The whole cell set (PCell and SCell(s)) is considered to avoid steering the UE to a PCell that offers few SCell possibilities and poor total throughput for the device.
Step 3: Resulting Action
Once the best cell set is provided, it is evaluated, and only if it is significantly better than the current cell set, it is configured to avoid unnecessary interruptions due to reconfiguration. The resulting action could be a handover (HO) from a PCell to another or a reselection of SCell(s). The UE is kept in place for the next session, using cell reselection priorities when it goes to idle or inactive mode.
Advanced Traffic Steering Benefits Everyone
Delivering a satisfactory user experience has always been a top priority for CSPs. Though there are many factors that make this difficult. The complexity of more frequencies in 5G, diverse devices with different capabilities, and service requirements add to their challenge. This requires a capable traffic steering solution.
Ericsson’s Advanced Multi-Layer Coordination optimizes for maximum throughput, which is what everyone wants. The company is constantly in conversation with CSPs to understand their needs and expectations. From these conversations they develop solutions that will lead to new service requirements and performance expectations.
With Ericsson Advanced Multi-Layer Coordination, service providers can make the most out of their spectrum investments. All while achieving 5G service differentiation, supporting energy savings and keeping 5G Standalone networks future-proof.
For more on the topic of Advanced Traffic Steering and Ericsson’s solution, check out their blog post.
