On Revealing the ARQ Mechanism of MSTV

Abstract

Ensuring a high customer satisfaction by monitoring Quality of Experience (QoE) aspects has become common practice for service providers. Such monitoring solutions, together with underlying QoE models, are mostly limited to measures captured in the core or access network and may thus neglect the QoE impact of recovery mechanisms deployed at client-side, e.g., FEC or ARQ. This limitation makes QoE models prone to mispredict QoE and consequently may lead the operators to misleading interpretations of customer experience. In this paper, we empirically study the behavior of the Microsoft TV Set-top Box (STB) with respect to the deployed ARQ recovery mechanism. As the ARQ implementation details of the STB are proprietary, we implement and simulate three ARQ algorithms of different complexities and evaluate their performance by comparing with corresponding empirical measurements. This comparison reveals insights into the ARQ scheme implemented in the STB. Moreover, it leads us to speculate that MSTV uses simple ARQ schemes which are sufficient to drastically improve the QoE in the presence of a multitude of loss patterns.

A QoE Perspective on Sizing Network Buffers

“…The importance of smoothing the sending rate is often ignored in available video assessment tools such as EvalVid, making them inapplicable for this study. We note that Set-top-Boxes in IPTV networks often use proprietary retransmission schemes that request lost packets once [24]. Due to the unavailability of exact implementation details we do not account for such recovery.…”