Wireless networks have long evolved from primarily voice-only services to converged voice, video, and data traffic, with a recent exceptional mobile data explosion due to the introduction of new technologies placing an unparalleled burden on IP-based infrastructures. Wireless network resources such as radio spectrum and transport resources are limited and costly, and need to be shared among many users and applications. Overprovisioning a wireless network cannot be a feasible solution to ensure an optimal Quality of Experience to the final user.

A Policy and Charging Control framework to standardise QoS evaluation

At the heart of the Evolved Packet Core (EPC), the core network supporting both LTE and legacy GSM-UMTS Radio Access Networks, the 3GPP has developed a comprehensive Policy and Charging Control (PCC) framework, with the goal of standardising QoS and policy mechanisms for deployments involving multiple vendors. To implement QoS, the 3GPP standard has defined a bearer model for the logical differential treatment of traffic with different QoS requirements, while the QoS Class Indicator (QCI) specifies the treatment of IP packets received on a specific bearer.

QoS Testing – how?

A comprehensive service quality validation of a wireless network must certainly involve load testing, where the network is saturated – up to a congestion point – with a mix of realistic traffic services originated by a multitude of subscribers. Detailed measurements of the most relevant KPIs that identify QoE will then need to be analysed for an accurate evaluation of network performance. QoS testing can be carried out at different levels. Given the complexity and the size of current traffic mixes, the method which is closest to the live network behaviour directly involves the radio interface. In this way, all interfaces and network elements are included, all joint effects are investigated and the real user experience can be evaluated.

QoS Testing with PRISMA RAN test solutions

Our multiterminal simulators provide realistic emulations involving also real radio conditions and mobility, with the ability to replicate a configurable mix of traffic services with different levels of traffic load across multiple cells, closely mimicking the real services that service providers will deploy. Exhaustive graphical reports detailing KPIs and performance analysis allow an extensive QoE investigation.