Network Performance Evaluation

The Mobile Networks department has experience in developing network performance measurement solutions for:

  • In-lab deployments
  • Pre-commercial systems
  • Commercial systems
  • Running systems
  • Field trials

Special effort is put on the accuracy of measurements

  • Calibration of equipment and systems
  • Innovative measurement tools and techniques
  • Main objective is to reduce errors induced by pre-conceived ideas about system behavior

Our approach is top-down

  • Measurements are used to identify problems and model systems
  • Innovative solutions are then applied to solve such issues

Technologies

Wireless LANs

  • Calibration of measurement devices to assure performance
    • Analysis of the performance of single-radio and multi-radio setups based on off-the-shelf hardware and software solutions
    • Patent application on technique to assess the ability of measurement devices to sense the presence of transmissions
  • WLAN load measurements
    • Analysis of the performance of traditional load measurement techniques based on active measurements
    • Devised solutions to improve the accuracy of delay and delay dispersion based tools that can be used to improve the performance of typical applications
    • Design and current implementation of a tool to perform distributed measurements of load in order to optimize end-user experience.
  • Detection of hidden traffic transmissions
    • Modeling Inter-relation between losses and hidden transmissions
    • Currently studying the use of these findings to improve WLAN optimization tools
  • VoIP over WLAN characterization
    • Designed and implemented a fully instrumented multi-user WLAN scenario
    • Voice perceived quality (by E-Model) calculation in different load conditions
    • Devised measurement-based model of the VoIP call loading and devised a call admission control method based the model.

 

UMTS/HSPA

  • Throughput and delay analysis of HSDPA and WCDMA
    • Active measurements
    • Study with respect to packet size and connection time
    • Discovery of resource allocation strategies and flaws in commercial deployments
    • Experience calibrating and assessing performance of running 3G deployments
  • Voice over IP quality estimation in HSDPA and WCDMA
    • Study of skype
  • Analysis of the performance of TCP traffic over 3,5G cellular network
    • TCP behavior with respect to 3GPP protocols
    • Impact of Spurious Retransmission Timeouts (SRTOs) on the overall network performance
    • Case of file transfer
    • Case of web surfing
    • Identification of usual interworking issues between TCP performance and actual configuration of commercial equipment.
  • Femtocells
    • Iuh interface
    • Active measurements for throughput and delay estimation

 

3G-WLAN interworking

  • Design and implementation of UMTS/HSDPA – WLAN interworking scenario
    • In-lab scenario using the 3.5G cellular testbed
    • Life scenario using commercial operator HSDPA/UMTS/GPRS network and campus WLAN
  • Design and analysis of vertical handoff schemes
    • Automatic measurement and assessment of handoff procedures
    • Analysis of the impact on quality of VoIP applications of handoff
    • Implementation a measurement based SIP vertical handoff scheme
  • VoIP assessment in interworking scenarios
    • Assessment of performance of typical VoIP codec in loaded scenarios
    • Assessment of the quality of Skype calls in interworking scenarios

 

LTE/LTE-A and EPC

  • Acquiring knowledge/experience on LTE/LTE-A and EPC architecture and protocols
  • LIPA/SIPTO, Mobility management, traffic offloading