Maria João Nicolau

The Smartphone-Based Offline Indoor Location Competition at IPIN 2016: Analysis and Future Work

This paper presents the analysis and discussion of the off-site localization competition track, which took place during the Seventh International Conference on Indoor Positioning and Indoor Navigation (IPIN 2016). Five international teams proposed different strategies for smartphone-based indoor positioning using the same reference data. The competitors were provided with several smartphone-collected signal datasets, some of which were used for training (known trajectories), and others for evaluating (unknown trajectories). The competition permits a coherent evaluation method of the competitors’ estimations, where inside information to fine-tune their systems is not offered, and thus provides, in our opinion, a good starting point to introduce a fair comparison between the smartphone-based systems found in the literature. The methodology, experience, feedback from competitors and future working lines are described.

Wi-Fi fingerprinting in the real world - RTLS@UM at the EvAAL competition

Research and development around indoor positioning and navigation is capturing the attention of an increasing number of research groups and labs around the world. Among the several techniques being proposed for indoor positioning, solutions based on Wi-Fi fingerprinting are the most popular since they exploit existing WLAN infrastructures to support software-only positioning, tracking and navigation applications. Despite the enormous research efforts in this domain, and despite the existence of some commercial products based on Wi-Fi fingerprinting, it is still difficult to compare the performance, in the real world, of the several existing solutions. The EvAAL competition, hosted by the IPIN 2015 conference, contributed to fill this gap. This paper describes the experience of the RTLS@UM team in participating in track 3 of that competition.

A realistic evaluation of indoor positioning systems based on Wi-Fi fingerprinting: The 2015 EvAAL–ETRI competition

This paper presents results from comparing different Wi-Fi fingerprinting algorithms on the same private dataset. The algorithms where realized by independent teams in the frame of the off-site track of the EvAAL-ETRI Indoor Localization Competition which was part of the Sixth International Conference on Indoor Positioning and Indoor Navigation (IPIN 2015). Competitors designed and validated their algorithms against the publicly available UJIIndoorLoc database which contains a huge referenceand validation data set. All competing systems were evaluated using the mean error in positioning, with penalties, using a private test dataset. The authors believe that this is the first work in which Wi-Fi fingerprinting algorithm results delivered by several independent and competing teams are fairly compared under the same evaluation conditions. The analysis also comprises a combined approach: Results indicate that the competing systems where complementary, since an ensemble that combines three competing methods reported the overall best results.

Efficiency of PRI and WRR DiffServ Scheduling Mechanisms for Real-Time Services on UMTS Environment

The next generation of mobile phones will be probably all-IP based enabling users to access Internet services. In order to make this possible a satisfactory quality of service, at least equal to the fixed Internet, must be ensured. To achieve this goal an end-to-end QoS system must be constructed. Another fact is the dominance of IP over other technologies due, in large measure, to its characteristic of working with heterogeneous technologies. Consequently, being IP the common denominator on a heterogeneous environment, it is important to develop end-to-end IP QoS guarantees for the different applications over distinct access technologies. This is particularly important for cellular wireless networks due to the ever growing expansion of mobile phone users. One way to contribute to this goal is to apply DiffServ QoS mechanisms to UMTS technology in order to model an End-to-End QoS communication system. A mapping of DiffServ CodePoints into UMTS classes can be applied in order to get efficient PHB configurations. This paper proposes an architecture to support end-to-end quality of service to several application services running on mobile UMTS user agents and communicating with servers located in a wired internet. The proposed architecture is based on a DiffServ model, where QoS parameters are set either by the user agent or by the SGSN. In particular, RED queue management and PRI or WRR scheduling policies are enforced. Different UMTS traffic classes are mapped into different DiffServ parameters. The performance of this architecture has been evaluated by simulation using NS, assuming different network load scenarios. In particular, the delay and packet loss experienced by VoIP, Video, FTP and HTTP traffic are evaluated in the cases of PRI and WRR scheduling policies, and compared to those measured when DiffServ is not implemented. Finally, a revenue function to estimate the profits that an ISP could expect by using a DiffServ implementation on IP UMTS core routers is proposed.

Engaging participants for collaborative sensing of human mobility

Human mobility has been widely studied for a variety of purposes, from urban planning to the study of spread of diseases. These studies depend heavily on large datasets, and recent advances in collaborative sensing and WiFi infrastructures have created new opportunities for generating that data. However, these methods and procedures require the participation of a significant community of users through extended periods of time. In this paper, we address the problem of how to engage people to participate in the data collection process. We have conducted a user study on the utilisation of a mobile collaborative sensing application. We have found that users react positively to campaigns, but it is difficult to keep them participating for long periods of time. We also hypothesise that one must close the loop, rewarding the participants with services based on the collected data, eventually showing that there is added value obtainable from crowd sourcing.

A new path probing strategy for inter-domain multicast routing

Many already in use applications require the provision of QoS services from the underlying network infra-structure. This is particularly true for multicast, since it involves many participants at very sparse locations usually aiming to receive or send multimedia real-time streams. One way to provide QoS is through routing, since QoS aware multicast routing protocols can find feasible multicast trees. In this paper an inter-domain QoS multicast routing protocol is presented, specifically designed for the hierarchical inter-domain scenario, where requirements like intra-domain independency and policy awareness should be met. Emphasis is given to the path probing mechanism used to connect new members to the multicast tree, stressing how it differs from others. Simulation results show that despite using a less aggressive and simplified probing mechanism-more suitable for inter-domain scenarios-the proposed routing strategy can build multicast trees with metrics similar to those build by more aggressive techniques, with considerable less effort.

A Probabilistic Interest Forwarding Protocol for Named Data Delay Tolerant Networks

Delay Tolerant Networks (DTN) were designed to allow delayed communications in mobile wireless scenarios where direct end-to-end connectivity is not possible. Nodes store and carry packets, deciding whether to forward them or not on each opportunistic contact they eventually establish in the near future. Recently, Named Data Networking (NDN) have emerged as a completely new paradigm for future networks. Instead of being treated as source or destination identifiers, nodes are viewed as consumers that express interests on information or producers that provide information. Current research is carried on the combination of these two concepts, by applying data-centric approach in DTN scenarios. In this paper, a new routing protocol called PIFP (Probabilistic Interest Forwarding Protocol) is proposed, that explores the frequency of opportunistic contacts, not between the nodes themselves, but between the nodes and the information, in order to compute a delivery probability for interest and data packets in a Named Data Delay Tolerant network (ND-DTN) scenario. The protocol design and a prototype implementation for The ONE Simulator are both described. Simulation results show that PIFP presents significant improvements in terms of interest satisfaction, average delay and total cost, when compared to other ND-DTN approaches recently proposed.

QoS-aware architecture for FHMIP micromobility

Wireless networks will certainly run applications with strict QoS requirements and so, micro-mobility protocols such as fast hierarchical mobile IPv6 (FHMIP) are useful tools to accomplish this new feature. The FHMIP is an effective scheme to reduce Mobile IPv6 handover disruption, however it does not support applications QoS requirements. Therefore, in order to provide QoS guarantees for real-time applications it is necessary to develop new traffic management schemes; this implies the optimization of network mobility support and also some network congestion control. A traffic management scheme of this type should take into account the QoS requirements of handover users and should implement a resource management (RM) scheme in order to achieve this. In this paper, a new RM scheme for the DiffServ QoS model is proposed. This new scheme is implemented by access routers as an extension to FHMIP micromobility protocol. In order to prevent QoS degradation of the existing traffic, access routers should evaluate the impact of admitting a new mobile node (MN), previously to the handover. This evaluation and sequent decision on wether admitting or refusing MNs traffic is based on a measurement-based admission control (MBAC) algorithm. This architecture, that has been implemented and tested using ns-2, includes a simple signaling protocol, a traffic descriptor and exhibits an adaptive behavior to traffic QoS requirements. All the necessary measurements are aggregated by class-of-service, thus avoiding maintaining state on the individual flows.

A Survey on vehicular communication technologies

This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundacao para a Ciencia e Tecnologia ˆ within the Project Scope: UID/CEC/00319/2013

A QoS-enabled resource management scheme for F-HMIPv6 micro mobility approach

In the near future, wireless networks will certainly run real-time applications with special Quality of Service (QoS) requirements. In this context micro mobility management schemes such as Fast Handovers over Hierarchical Mobile IPv6 (F-HMIPv6) will be a useful tool in reducing Mobile IPv6 (MIPv6) handover disruption and thereby to improve delay and losses. However, F-HMIPv6 alone does not support QoS requirements for real-time applications. Therefore, in order to accomplish this goal, a novel resource management scheme for the Differentiated Services (DiffServ) QoS model is proposed to be used as an add-on to F-HMIPv6. The new resource management scheme combines the F-HMIPv6 functionalities with the DiffServ QoS model and with network congestion control and dynamic reallocation mechanisms in order to accommodate different QoS traffic requirements. This new scheme based on a Measurement-Based Admission Control (MBAC) algorithm is effective, simple, scalable and avoids the well known traditional resource reservation issues such as state maintenance, signaling overhead and processing load. By means of the admission evaluation of new flows and handover flows, it is able to provide the desired QoS requirements for new flows while preserving the QoS of existing ones. The evaluated results show that all QoS metrics analyzed were significantly improved with the new architecture indicating that it is able to provide a highly predictive QoS support to F-HMIPv6.