Access-agnostic service delivery, lowering platform cost for delivering them, a more flexi environment to rollout newer applications with blended multimedia services support ‘+’ the revenue increase resulting from these added new services have made carriers march towards LTE as the successive carrier technology. The LTE IMS network has evolved to support the multimedia services over IP with its layered architecture, separating, the signalling, the media and the application functions. This separation reduces the stress on service delivery and a service is made available without worrying how will it be routed, via which network or to what type of access device will it be published. The 3GPP policy and charging control (PCC) system acts as an entry point for end-to-end service control. The TS 23.203 in-specific standardizes a set of QoS Class Identifiers (QCI) for different services with QoS parameters classified via priority levels, allowed packet delays/error rate, resource allocation types (guaranteed/non-guaranteed bit rates). Policies can be set in the PCRF as per above classifiers, differently – as per subscription, location, access gateway or access device type…example, for HD voice service, the policy can be set for a higher bandwidth/quality codec negotiation and an emergency call can be set for highest QoS. Diameter based Rx interface offers the path for application developers to talk to the PCC architecture and facilitate the creation of newer applications and move beyond the flat rate data plans to offer more innovative service bundles. The Rx interface can be adapted for:

• Gx-to-Rx session mapping based on IP Address, session IP, Subscriber Identity or any other custom parameters.
• Operator defined rounding off logic while enforcing QoS, helping CSPs modify services in differential categories like good, poor, bad or average and charge premiums.
• QoS and Charging based on Audio / Video call separately.
• QoS and Charging based on Audio / Video Quality.

Service mix including voice/HD voice/video, critical/non-critical voice/video, video (buffered) or live video streaming, interactive gaming, Wi-Fi calling, push-to-talk services, email services and content sharing, presence and rich IM sessions can be addressed with above parameters pre-defined for each. Sterlite Tech’s-Elitecore NetVertex PCRF enables CSPs support advance use cases in the VoLTE architecture, including, though not limited to:

• Conference Calling
• Dynamic QoS
• Off-Net Charging
• On-Net Charging
• Event Based Charging
• Differential Charging
• Roaming
• Emergency Call
• CUG & FnF (Friends and Family Plans)
• Optimization of QoS
• RTCP Vs. non RTCP handling

The cloud and virtualized ready PCRF can be deployed for VoLTE & Data or parallel PCRF alongwith the existing PCRF remaining undisturbed to support the data traffic and dedicated PCRF for VoLTE voice. This model also balances the increased subscriber and signalling load, along with offering a smooth transition path to all-IP service architecture of VoLTE.  It also supports circuit switch fall-back (CSFB) and single radio voice call continuity (SRVCC) fall-back for service continuity and is highly reliable with a two-way geo-redundancy and both Gx/Rx session continuity for local and geo-redundant failovers. To read more about Elitecore’s offering for VoLTE refer:Click here References: http://www.3gpp.org/technologies/keywords-acronyms/1629-rx_interface