LTE networks are all-IP-based without a circuit switched domain, traditionally used to support voice services. Many networks still support voice in LTE using the CSFB functionality, i.e. falling back from LTE to 2G or 3G in order to establish the call. Having passed the lab proof-of-concept, operators are now moving voice over LTE (VoLTE) based on the IP multimedia subsystem (IMS) into a precommercial stage. This is a critical phase, since voice services still account for a large share of their revenues. Maintaining and improving quality levels of voice services is decisive in such a highly competitive market. This webinar presents the technical background to VoLTE (based on IMS) and explains how to measure voice quality in live networks. It also illustrates the impact of radio conditions and IP impairments (e.g. jitter or audio delay) to audio quality.

The main focus is on the field testing aspects of VoLTE. The capabilities for testing VoLTE in the lab will also be touched upon.

Attendees Will Learn:

  • Technology behind VoLTE based on IMS
  • Key challenges involved in quantifying end-user experience in the field
  • Impact on voice quality (MOS) resulting from radio conditions and IP impairments


  • Basic understanding on how voice is implemented in 2G / 3G
  • Basic knowledge of LTE 3GPP Release 8 principles

Who Should Attend:

  • Field testing engineers
  • Engineering and lab managers
  • Research and principal engineers
  • Software and protocol development engineers
  • Network and systems & test engineers
  • Application and support engineers

Massimiliano Mannelli,
Product Manager at SwissQual, a Rohde & Schwarz Company in Zuchwil (Switzerland)

Massimiliano Mannelli joined SwissQual, a Rohde & Schwarz company in Zuchwil (Switzerland), as a product manager in 2013. He is responsible for the post-processing portfolio of optimization and benchmarking systems. Prior to this, he headed the cell planning group at Blu SpA, an Italian mobile network operator, and also worked at Actix Ltd. as a product manager for GSM/GPRS/EDGE and E2E service optimization. From 2005 to 2012, he was with Nokia as a solution manager in the service management department and, after the founding of Nokia Siemens Networks, became a business development manager for customer experience management products and solutions. Massimiliano holds a degree in electronic engineering from the University of Florence, Italy, and qualified to work as an engineer at the University of Padua, Italy.

Meik Kottkamp,
Technology Manager, Test & Measurement Division, Rohde & Schwarz, Munich

Meik Kottkamp is technology manager within the test & measurement division of Rohde & Schwarz in Munich. He is responsible for strategic marketing and product portfolio development regarding LTE, LTE-Advanced, HSPA+ and EDGE Evolution. Meik joined Rohde & Schwarz in August 2007. From 1996 to 2007, he worked with Siemens Mobile Communication Networks and Terminals. As standardization manager he was leading a group responsible for the Siemens standardization strategy in 3GPP TSG RAN. Later he was involved in predevelopment projects on broadband technologies Flash OFDM, WiMAX and HSPA+. After creation of NSN in early 2007 he joined LTE product management group. Meik holds a degree of electrical engineering from the University of Hannover / Germany.