Role of a Dedicated PCRF in VoLTE and Its Significance in 5G VoNR

6 min readJun 7, 2023

Preparing voice services for 5G

As operators transition from 4G LTE services to 5G, they must ensure their voice services are prepared for the change. The emergence of new technologies and standards with 5G networks necessitates updating voice services to meet the next-generation communication requirements.

Voice services traditionally relied on circuit-switched (CS) networks or CS fallback. Although these methods have worked in the past, next-gen 5G networks don’t support them. This incompatibility arises due to the fundamental differences in architecture and underlying technologies between 4G and 5G. Therefore, operators must migrate their voice services to Voice over LTE (VoLTE) or Voice over New Radio (VoNR) before offering 5G services.

To support VoLTE or VoNR seamlessly, the adoption of dedicated Policy and Charging Rules Functions (PCRF) for data and voice services is essential. By leveraging a dedicated specifically-designed PCRF solution for VoLTE, operators can efficiently manage and control various aspects of voice services in a reliable network environment. With VoLTE PCRF, operators can enforce policy and charging rules for voice traffic, ensuring network resource prioritization and efficient utilization.

Benefits of VoLTE

VoLTE allows voice calls over a 4G LTE network while using the same IP-based network as data traffic. VoLTE offers numerous advantages over traditional circuit-switched voice services, including improved call quality, faster call setup times, and the ability to make simultaneous voice and data connections.

One of the major benefits of VoLTE includes its significant call quality. The narrowband voice channel limits traditional circuit-switched voice calls, reducing the audio quality. In contrast, VoLTE leverages the wider bandwidth available on 4G LTE networks, allowing for high-definition voice calls with crystal-clear audio.

Moreover, VoLTE enables the simultaneous use of voice and data services and eliminates call disruptions by utilizing the IP-based network, allowing the users to browse the internet, stream content, or use other data services while on a voice call.

Designed for 5G networks, Voice over New Radio (VoNR) is similar to VoLTE, which enables voice and data services. There is, however, a significant difference between VoNR and VoLTE. VoNR does not support the continuation of voice calls when switching between 5G and older 3G networks. To fully utilize 5G services, integration with an IP Multimedia Subsystem (IMS) is necessary.

Essential components of VoLTE and the role of a dedicated PCRF

To transition to VoLTE, operators must deploy an IP Multimedia Subsystem (IMS) network that provides the necessary VoLTE infrastructure. The IMS network consists of several components, including a Call Session Control Function (CSCF), an IMS Home Subscriber Server (HSS), Online Charging System (OCS), and a PCRF.

The CSCF is responsible for call control and routing within the IMS network. It handles the signaling required for establishing and maintaining voice calls, ensuring that voice traffic is appropriately managed and directed. The HSS, on the other hand, serves as a central database that stores subscriber information such as user profiles, authentication data, and service entitlements. This information is crucial for the proper functioning of VoLTE services.

The OCS is a critical component of the IMS network. It handles real-time credit control and charging for voice and data services, ensuring accurate user billing.

The PCRF is critical in enforcing quality of service (QoS) policies and network resource allocation. A dedicated PCRF for VoLTE ensures that the appropriate QoS parameters are applied to voice traffic, prioritizing voice calls and guaranteeing high-quality voice services.

Importance of a dedicated voice network

The rise of Voice over Internet Protocol (VoIP) and voice and data network convergence raises the demand for dedicated voice networks. Operators now often use packet-switched networks that carry both voice and data traffic but prioritizing and optimizing voice transmission separately to ensure quality and reliability becomes challenging. Additionally, as listed below, several other reasons reinforce why operators should maintain a dedicated VoLTE network:

It optimizes the quality of both VoLTE and data traffic and allows for granular control over these types of traffic, ensuring that network resources are utilized efficiently.
It simplifies troubleshooting or issue resolution, allowing easy identification of the problems when voice and data traffic are separated.
It increases flexibility and scalability to accommodate user demands and future growth, enabling network infrastructure to adapt to changing requirements without affecting voice services.
It ensures the reliability and availability of voice networks and prevents service disruptions during peak data usage periods, allowing users to continue to rely on uninterrupted voice communication.
It treats the voice network independently and allows efficient handling of service requests, upgrades, congestion, and outages, ensuring optimal performance and minimal impact on data services.
It optimizes overall network bandwidth, allowing for specific allocation and optimization techniques tailored to voice and data traffic and maximizing efficiency.
It reduces costs by leveraging specialized vendors for cost-effective voice services, allowing operators to utilize their expertise and achieve cost savings without compromising quality.
It enhances security by isolating voice traffic from data traffic and helps protect voice communication, minimizing the potential impact of data-related security breaches or vulnerabilities.

Importance of dedicated PCRFs for voice and data

While the trend is towards convergence and integration of voice and data services in more unified networks, having a dedicated PCRF for voice and data offers operators greater control, flexibility, and the ability to tailor services to meet specific requirements and optimize the customer experience. A dedicated PCRF for voice and data enables operators to effectively manage, control, and monetize their network resources while delivering high-quality services and meeting customer expectations. Here are some key reasons why operators should deploy a dedicated PCRF for voice and data services:

To ensure uninterrupted service continuity for voice and data, regardless of congestion, through fault isolation and redundancy.
To facilitate voice network upgrades without disruptions to other service networks like data, minimizing customer impact.
To allocate network resources efficiently and prevent congestion’s impact on voice and data services, preserving voice service quality during peak data usage.
To independently scale voice and data services based on demand, optimizing resource allocation and network expansion cost-effectively.
To streamline management and troubleshooting processes, empowering operators by targeted traffic monitoring, problem identification, and resolution capabilities offered by separate PCRFs.
To implement service-specific QoS parameters such as low latency and minimal jitter for seamless voice calling and low latency with sufficient bandwidth for optimal data usage experience.

Enhance Voice Services with Alepo PCF + PCRF

Technology partners play a significant role in accelerating VoLTE deployment and 5G migration. Telecom product companies like Alepo, offering PCRF and PCF (Policy Control Function) solutions, assist operators in rapidly rolling out VoLTE and 5G voice services. These solutions offer a range of features to optimize voice service delivery and provide a seamless user experience.

With Alepo PCF + PCRF, operators can:

Implement QoS management

With Alepo PCRF for 5G standalone deployments and Alepo PCRF for VoLTE services, operators may specify and enforce particular QoS criteria like low latency and minimal packet loss. These technologies ensure that voice calls maintain the desired level of performance and reliability.

Customize policies for voice services

Alepo’s PCRF and PCF solutions allow operators to define and customize policies, including QoS prioritization, bandwidth allocation, and ‘push to X’ features (talk, video, chat). These solutions also allow the prioritization of multimedia services for uninterrupted emergency communications. Operators can fine-tune voice service behavior to effectively meet both network requirements and subscriber preferences.

In short, by utilizing Alepo PCF + PCRF, operators can optimize voice service performance, effectively manage network resources, and deliver a superior voice calling experience to their subscribers in LTE and 5G networks.

Conclusion

The transition of voice services to VoLTE is critical for operators planning to upgrade to 5G networks. By adopting a dedicated PCRF for voice and data services, operators can enforce QoS policies, optimize network resources, and ensure a seamless voice-calling experience. VoLTE offers significant advantages over traditional circuit-switched voice services, including improved call quality and simultaneous voice and data connections. Deploying the necessary infrastructure and partnering with technology providers like Alepo enables operators to future-proof their networks for the 5G era and deliver cutting-edge communication services. Embracing VoLTE and a dedicated PCRF empowers operators to thrive in the evolving telecommunications landscape, unlock the potential of 5G, and provide superior service experiences to subscribers.

Would you like to explore further details about VoLTE PCRF and witness its impact on accelerating network performance, service monetization, and network reliability? Email market.development@alepo.com and our team of experts will contact you to address all your queries and show you a quick demo.

Source: Alepo Blog