Positioning of High-speed Trains using 5G New Radio Synchronization Signals

We study positioning of high-speed trains in 5G new radio (NR) networks by utilizing specific NR synchronization signals. The studies are based on simulations with 3GPP-specified radio channel models including path loss, shadowing and fast fading effects. The considered positioning approach exploits measurement of Time-Of-Arrival (TOA) and Angle-Of-Departure (AOD), which are estimated from beamformed NR synchronization signals. Based on the given measurements and the assumed train movement model, the train position is tracked by using an Extended Kalman Filter (EKF), which is able to handle the non-linear relationship between the TOA and AOD measurements, and the estimated train position parameters. It is shown that in the considered scenario the TOA measurements are able to achieve better accuracy compared to the AOD measurements. However, as shown by the results, the best tracking performance is achieved, when both of the measurements are considered. In this case, a very high, sub-meter, tracking accuracy can be achieved for most (>75%) of the tracking time, thus achieving the positioning accuracy requirements envisioned for the 5G NR. The pursued high-accuracy and high-availability positioning technology is considered to be in a key role in several envisioned HST use cases, such as mission-critical autonomous train systems.Comment: 6 pages, 5 figures, IEEE WCNC 2018 (Wireless Communications and Networking Conference

Graph-based particle filter in indoor positioning

Tässä diplomityössä käsitellään sisätilapaikannusta ja siihen tarkoitettua suodatinta WLAN-tukiasemista sekä BLE-lähettimistä saatujen mittausten avulla. Työssä esitellään tarkemmin sisätilapaikannusmenetelmä, joka käyttää mittausten lisäksi tehokkaasti myös rakennuksen pohjapiirustukseen perustuvaa karttainformaatiota käyttäjän sijainnin määrittämisessä. Suodatuksen taustalla olevan teorian lisäksi työssä esitellään suodattimen toiminta ja saadut tulokset todellisia mittauksia sisältävien testireittien avulla. Työssä esiteltävä graafipohjainen partikkelisuodatin on graafipohjaiselle karttarakenteelle luotu partikkelisuodatin, joka rajoittaa käyttäjän sijaintia ja liikkumista rakennuksen rakenteiden mukaisesti. Graafipohjainen karttarakenteessa käytäviä sekä pieniä huoneita mallinnetaan solmupisteiden välisten linkkien avulla ja suurempia avoimia alueita mallinnetaan avoimina tiloina, jossa käyttäjän liikkuminen on mahdollista kahdessa ulottuvuudessa. Tässä työssä esitellään myös graafipohjainen tilamalli, joka mallintaa käyttäjän liikkeen mahdollisimman todenmukaisesti käyttäjän päämäärätietoisuuden huomioiden. Graafipohjaista partikkelisuodattimen suorituskykyä testataan työssä esitetyllä karttarakenteella Tampereen teknillisen yliopiston Tietotalosta kerättyjen testireittien avulla kahdella eri mittaustiheydellä. Suodattimen antamia paikannustuloksia verrataan eri tilamallia käyttävän graafipohjaisen partikkelisuodattimen sekä vakionopeusja vakiopaikkamallia käyttävien Kalmanin suodattimien tuloksiin. Saatujen tulosten ja niistä tehtyjen analyysien pohjalta, esitellyn suodattimen paikannustarkkuus havaitaan vertailumenetelmiä paremmaksi lähes jokaisessa testitilanteessa

DoA and ToA Estimation, Device Positioning and Network Synchronization in 5G New Radio : Algorithms and Performance Analysis

Location information plays a significant role not only in our everyday life through various location-based services, but also in emerging technologies such as virtual reality, robotics, and autonomous driving. In contrast to the existing and earlier cellular generations, positioning has been considered as a key element in future cellular networks from the very beginning of the fifth generation (5G) standardization process. Even though the earlier generations are capably of providing coarse location estimates, the achieved accuracy is far from the expected even sub-meter positioning accuracy envisioned in the context of 5G networks. In general, 5G new radio (NR) networks provide a convenient infrastructure for positioning by means of wider bandwidths, larger antenna arrays, and even more densely deployed networks especially at high millimeter wave (mmWave) frequencies. Building on dense 5G NR networks, this thesis focuses on the development of novel network-centric positioning frameworks by exploiting the existing NR reference signals. The contributions in this thesis can be grouped into topics based on the considered frequency ranges and the employed beamforming (BF) schemes therein. First, novel cascaded algorithms for sequential device positioning are proposed assuming 5G NR networks operating at the lower sub-6 GHz frequency range and equipped with digital BF capabilities. In the first stage of the cascaded solution, two sequential estimators are proposed for joint direction of arrival (DoA) and time of arrival (ToA) estimation facilitating the received reference signals. Thereafter, the second-stage sequential estimators employing the obtained DoA and ToA estimates are proposed for joint positioning and network synchronization resulting in not only device location estimates, but also clock parameter estimates that are obtained as a valuable by-product. Such a choice stems from the fact that the ToA estimates are not feasible for positioning as such due to the clock instabilities in low-cost devices and the insufficient level of synchronization in the cellular networks. Second, a similar cascaded algorithm for joint positioning and network synchronization is proposed in the context of dense mmWave 5G networks and fundamentally different analog BFs. In particular, a novel joint DoA and ToA estimator is proposed by fusing information from multiple received beams based on a novel beam-selection method. In addition, the theoretical performance limits are derived and compared to those obtained using the digital BFs. The cascaded framework is completed with the second-stage positioning solution in a similar manner as in the case of digital BFs. The performance of both frameworks is evaluated and analyzed in various scenarios using extensive computer simulations relying on the latest 5G NR numerology and a ray-tracing tool. Overall, this thesis provides valuable insights into practical positioning algorithms and their performance when relying solely on the 5G NR networks and available signalling therein. The obtained results in this thesis indicate that the envisioned sub-meter positioning accuracy is technically feasible using NR-based solutions

The bilateral advantage for famous faces: interhemispheric communication or competition?

The bilateral advantage for the perception of famous faces was investigated using a redundant target procedure. In experiment 1 we compared simultaneous presentation of stimuli (a) bilaterally and (b) one above the other in the central field. Results showed a redundancy advantage, but only when faces were presented bilaterally. This result lends support to the notion of interhemispheric communication using cross-hemisphere representations. Experiment 2 examined the nature of such communication by comparing bilateral presentation of identical face images, with bilateral presentation of different images of the same person. When asked to make a familiar/unfamiliar face judgement, participants showed evidence for a redundancy advantage under both bilateral conditions. This suggests that the nature of the information shared in interhemispheric communication is abstract, rather than being tied to superficial stimulus properties

Natalizumab treatment shows low cumulative probabilities of confirmed disability worsening to EDSS milestones in the long-term setting.

Abstract Background Though the Expanded Disability Status Scale (EDSS) is commonly used to assess disability level in relapsing-remitting multiple sclerosis (RRMS), the criteria defining disability progression are used for patients with a wide range of baseline levels of disability in relatively short-term trials. As a result, not all EDSS changes carry the same weight in terms of future disability, and treatment benefits such as decreased risk of reaching particular disability milestones may not be reliably captured. The objectives of this analysis are to assess the probability of confirmed disability worsening to specific EDSS milestones (i.e., EDSS scores ≥3.0, ≥4.0, or ≥6.0) at 288 weeks in the Tysabri Observational Program (TOP) and to examine the impact of relapses occurring during natalizumab therapy in TOP patients who had received natalizumab for ≥24 months. Methods TOP is an ongoing, open-label, observational, prospective study of patients with RRMS in clinical practice. Enrolled patients were naive to natalizumab at treatment initiation or had received ≤3 doses at the time of enrollment. Intravenous natalizumab (300 mg) infusions were given every 4 weeks, and the EDSS was assessed at baseline and every 24 weeks during treatment. Results Of the 4161 patients enrolled in TOP with follow-up of at least 24 months, 3253 patients with available baseline EDSS scores had continued natalizumab treatment and 908 had discontinued (5.4% due to a reported lack of efficacy and 16.4% for other reasons) at the 24-month time point. Those who discontinued due to lack of efficacy had higher baseline EDSS scores (median 4.5 vs. 3.5), higher on-treatment relapse rates (0.82 vs. 0.23), and higher cumulative probabilities of EDSS worsening (16% vs. 9%) at 24 months than those completing therapy. Among 24-month completers, after approximately 5.5 years of natalizumab treatment, the cumulative probabilities of confirmed EDSS worsening by 1.0 and 2.0 points were 18.5% and 7.9%, respectively (24-week confirmation), and 13.5% and 5.3%, respectively (48-week confirmation). The risks of 24- and 48-week confirmed EDSS worsening were significantly higher in patients with on-treatment relapses than in those without relapses. An analysis of time to specific EDSS milestones showed that the probabilities of 48-week confirmed transition from EDSS scores of 0.0–2.0 to ≥3.0, 2.0–3.0 to ≥4.0, and 4.0–5.0 to ≥6.0 at week 288 in TOP were 11.1%, 11.8%, and 9.5%, respectively, with lower probabilities observed among patients without on-treatment relapses (8.1%, 8.4%, and 5.7%, respectively). Conclusions In TOP patients with a median (range) baseline EDSS score of 3.5 (0.0–9.5) who completed 24 months of natalizumab treatment, the rate of 48-week confirmed disability worsening events was below 15%; after approximately 5.5 years of natalizumab treatment, 86.5% and 94.7% of patients did not have EDSS score increases of ≥1.0 or ≥2.0 points, respectively. The presence of relapses was associated with higher rates of overall disability worsening. These results were confirmed by assessing transition to EDSS milestones. Lower rates of overall 48-week confirmed EDSS worsening and of transitioning from EDSS score 4.0–5.0 to ≥6.0 in the absence of relapses suggest that relapses remain a significant driver of disability worsening and that on-treatment relapses in natalizumab-treated patients are of prognostic importance

Graph-based particle filter in indoor positioning

Tässä diplomityössä käsitellään sisätilapaikannusta ja siihen tarkoitettua suodatinta WLAN-tukiasemista sekä BLE-lähettimistä saatujen mittausten avulla. Työssä esitellään tarkemmin sisätilapaikannusmenetelmä, joka käyttää mittausten lisäksi tehokkaasti myös rakennuksen pohjapiirustukseen perustuvaa karttainformaatiota käyttäjän sijainnin määrittämisessä. Suodatuksen taustalla olevan teorian lisäksi työssä esitellään suodattimen toiminta ja saadut tulokset todellisia mittauksia sisältävien testireittien avulla. Työssä esiteltävä graafipohjainen partikkelisuodatin on graafipohjaiselle karttarakenteelle luotu partikkelisuodatin, joka rajoittaa käyttäjän sijaintia ja liikkumista rakennuksen rakenteiden mukaisesti. Graafipohjainen karttarakenteessa käytäviä sekä pieniä huoneita mallinnetaan solmupisteiden välisten linkkien avulla ja suurempia avoimia alueita mallinnetaan avoimina tiloina, jossa käyttäjän liikkuminen on mahdollista kahdessa ulottuvuudessa. Tässä työssä esitellään myös graafipohjainen tilamalli, joka mallintaa käyttäjän liikkeen mahdollisimman todenmukaisesti käyttäjän päämäärätietoisuuden huomioiden. Graafipohjaista partikkelisuodattimen suorituskykyä testataan työssä esitetyllä karttarakenteella Tampereen teknillisen yliopiston Tietotalosta kerättyjen testireittien avulla kahdella eri mittaustiheydellä. Suodattimen antamia paikannustuloksia verrataan eri tilamallia käyttävän graafipohjaisen partikkelisuodattimen sekä vakionopeusja vakiopaikkamallia käyttävien Kalmanin suodattimien tuloksiin. Saatujen tulosten ja niistä tehtyjen analyysien pohjalta, esitellyn suodattimen paikannustarkkuus havaitaan vertailumenetelmiä paremmaksi lähes jokaisessa testitilanteessa

A method to enforce map constraints in a particle filter's position estimate

acceptedVersionPeer reviewe

Positioning and Tracking of High-speed Trains with Non-linear State Model for 5G and Beyond Systems

High-speed trains (HSTs) with fifth generation (5G) communications services, including both high rate data links and high reliability mission-critical services, are considered as one of the new industry verticals facilitated by the 5G connectivity. In this paper, we study positioning of HSTs in 5G new radio (NR) networks based on time difference of arrival (TDoA) and angle-of-arrival (AoA) measurements, obtained with specific 5G NR reference signals at the millimeter wave (mmWave) frequency. Moreover, the HST is tracked with an extended Kalman filter, where, instead of conventional linear state-transition model, we propose and derive a non-linear state-transition model, including the train position, absolute train velocity, and train heading. Furthermore, by introducing a state-dependent process variance for the angular velocity of the train, we show that the positioning performance of the HST can be significantly improved compared to the conventional linear state-transition modeling. Based on realistic simulations on a real-life high-speed track, we show that the proposed positioning engine can reach 95% percentile estimation accuracies of 2.3 m, 0.47 m/s, and 1.6 deg, for the train position, train velocity, and train heading, respectively, thus fulfilling the requirements specified by the 3GPP for machine control and transportation services.acceptedVersionPeer reviewe

Graph-Based Map Matching for Indoor Positioning

This article presents a probabilistic motion model that is based on an economical graph-based indoor map representation, such that the motion of the user is constrained according to the floor plan of a building. The floor plan is modeled as a combination of links and open space polygons that are connected by nodes. In the authors’ earlier work the link transition probabilities in this graph are proportional to the total link lengths that are the total lengths of the subgraphs accessible by choosing the considered link option, and this article extends this model to include open space polygons as well. A particle filter using the extended motion model in which all particles are constrained according to the map structure is presented. Furthermore, wireless local area network and Bluetooth Low Energy positioning tests show that the proposed algorithm outperforms comparison methods especially if the measurement rate is low.acceptedVersionPeer reviewe