QQSS 2021 Abstracts


Area 1 - QoS and QoE in Systems and Services

Full Papers
Paper Nr: 1
Title:

Per-flow Packet Loss Ratios Induced by an Overflowed Buffer

Authors:

Andrzej Chydzinski and Blazej Adamczyk

Abstract: Packet losses are common in TCP/IP networks. The main reason of that is the statistical multiplexing of flows at routers’ output buffers, resulting in random overflows of these buffers and dropping of packets. Although the losses caused by an overflowed buffer have been widely studied, these studies were mainly devoted to the aggregated traffic. Namely, the total loss ratio was analyzed, for all the packets arriving to the buffer, without distinction between separate flows. In this paper, we study the packet loss ratios suffered by distinct flows arriving to a common buffer. We first observe that the loss ratios of particular flows may differ significantly from each other, and from the total loss ratio. Then we single out the properties of the flow that may influence the per-flow loss ratio. We study also possible mutual dependencies between the flows, i.e. possibilities that the properties of one flow influence the loss ratios of other flows. Finally, we study the impact of the buffer size and the distribution of the service time (packet size) on the per-flow loss ratios, as well as their relations to ech other.
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Paper Nr: 2
Title:

DOP and Pseudorange Error Estimation in Urban Environments for Mobile Android GNSS Applications

Authors:

Przemyslaw Falkowski-Gilski and Zbigniew Lubniewski

Abstract: Just a couple of years ago, GNSS (Global Navigation Satellite Systems) were available only for a narrow group of users. Currently, with the outbreak of mobile devices, they are accessible to anyone and everywhere. Urban navigation or searching for POIs (Points of Interest) had become an everyday activity. With the availability of consumer electronics and wireless technologies, each user can obtain information considering his or her location even in an unknown environment. Additionally, network operators and service providers utilize this location-based information for monitoring and maintenance purposes. This paper is focused on a study, considering the DOP (Dilution of Precision) and pseudorange error estimation in case of Android-powered smartphones operating outdoors. It describes a measurement campaign, carried out in varying urban environments, with two types of excursions (by car and bicycle), including two popular consumer devices from different manufacturers. Based on this, respective conclusions and remarks are given. This work aims to aid not only users, but also application developers as well as device manufacturers and retailers, when it comes to providing precise and reliable products and services.
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Short Papers
Paper Nr: 3
Title:

Study on Speech Transmission under Varying QoS Parameters in a OFDM Communication System

Authors:

Monika Zamlynska, Przemyslaw Falkowski-Gilski, Grzegorz Debita and Bogdan Miedzinski

Abstract: Although there has been an outbreak of multiple multimedia platforms worldwide, speech communication is still the most essential and important type of service. With the spoken word we can exchange ideas, provide descriptive information, as well as aid to another person. As the amount of available bandwidth continues to shrink, researchers focus on novel types of transmission, based most often on multi-valued modulations, multiple channels and related sub-carriers. Currently, OFDM (Orthogonal Frequency Division Multiplexing) is widely utilized both in wired and wireless transmission. It includes terrestrial and online digital services, such as cellular systems and broadcasting standards. This paper is focused on varying QoS (Quality of Service) aspects, related with the OFDM telecommunication system, with respect to speech signals. It involves a group of four language sets, namely: American English, British English, German, and Polish. Results of this study may aid both researchers and professionals involved in designing everyday communication services as well as supplementary back-up services.
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Paper Nr: 4
Title:

Energy Efficiency Study of Audio-video Content Consumption on Selected Android Mobile Terminals

Authors:

Przemyslaw Falkowski-Gilski and Maciej Pankowski

Abstract: Mobile devices are widely used by billions of users worldwide. Thanks to their main advantage, which is portability, they should be fully operational as long as possible, without the need to recharge or connect them to external power sources. This paper describes a study, carried out on four different mobile devices, with different hardware and software parameters, running the Android operating system. The research campaign involved several scenarios, including consumption of audio-visual content by different means of wireless communication (cellular and Wi-Fi), designed to best reflect the common daily use of a modern smartphone. Those scenarios were based on a user experience survey conducted at the beginning of the study. Obtained results illustrate user preferences as well as resource consumption of multimedia on different devices with varying distribution of the Android OS.
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