Olariu, Cristian

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Olariu, Cristian
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Olariu, Cristian

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  • Publication
    VoIP Quality Monitoring in LTE Femtocells
    (IEEE, 2011-05-27)
    Olariu, Cristian 
    ;
    Ó Foghlú, Mícheál 
    ;
    Perry, Philip 
    ;
    Murphy, Liam, B.E. 
    The increasing number of users demanding voice and data communication through cellular networks has driven the need for higher network throughput rates and lower latency. LTE femtocells address this pressing problem by offloading cellular service providers networks and increase both coverage and capacity for their users. Assuming a wired DSL backhaul for these femtocells, this paper shows simulations exploring a case where the DSLAM represents the main bottleneck when the cellular network operator and the DSL provider do not collaborate. This paper introduces the concept of Intermediary Mean Opinion Score which may be employed at femtocell gateways to isolate network problems and feed into customer experience management. We also propose and investigate a technique of mapping the human audio recency into the MOS calculation. Results are presented to illustrate the information that can be extracted from a lightweight monitor in the network.
      450Scopus© Citations 12
  • Publication
    A QoS based call admission control and resource allocation mechanism for LTE femtocell deployment
    (IEEE, 2012-01-17)
    Olariu, Cristian 
    ;
    Fitzpatrick, John 
    ;
    Perry, Philip 
    ;
    Murphy, Liam, B.E. 
    Current trends show a growing number of femtocell deployments, this in turn will lead to increased volumes of voice traffic being transmitted through fixed broadband access networks such as Digital Subscriber Line. In this paper the issue of maintaining call quality through the resource constraint expedited forwarding queue of DSLAMs is investigated. A quality based Call Admission Control and resource allocation mechanism is provided to avoid resource overloading and call quality degradation. The ITU-T's E-Model is used for call quality monitoring and a message exchange interface between the mobile and fixed networks which allows dynamic adjustment to network resources is described and simulated. The results show that high voice call quality can be maintained.
      432Scopus© Citations 22