Romualdas Navickas

Prof. Romualdas Navickas

Vilnius Gediminas Technical University
orcid

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 June 2020 in Applied Sciences
Verified
Journal Article
Open access
PDF file
KKKarolis Kiela
Karolis Kiela
Vaidotas BarzdenasVaidotas Barzdenas
Vaidotas Barzdenas
MJMarijan Jurgo
Marijan Jurgo
VMVytautas Macaitis
Vytautas Macaitis
JRJustas Rafanavicius
Justas Rafanavicius
Romualdas NavickasRomualdas Navickas
Romualdas Navickas
The intelligent transport system (ITS) has become one of the most globally researched topics with a lot of investment and development resources being dedicated into it due to its foreseen impact on the economic growth of the transport sector. Currently there are two main vehicle-to-everything (V2X) technologies, whose primary application is focused on ITS, backed up by the key players of various automotive, telecommunication and transport industries: dedicated short-range communications (DSRC) and cellular vehicle-to-everything (C-V2X), respectively based on IEEE 802.11p and 3GPP LTE/5G NR. While DSRC already has deployments, C-V2X is expected to see larger scale trails and deployments in 2020. In this work, the authors provide insight and review into two main V2X technologies, DSRC and C-V2X, their core parameters, shortcomings and limitations, and explore the need for integration of IoT-based technologies into modern ITS solutions. A comprehensive overview and analysis of currently commercially available V2X products, their sub-blocks and features is provided.

22 August 2021 in Sensors
Verified
Journal Article
Open access
PDF file
KKKarolis Kiela
Karolis Kiela
MJMarijan Jurgo
Marijan Jurgo
VMVytautas Macaitis
Vytautas Macaitis
Romualdas NavickasRomualdas Navickas
Romualdas Navickas
In this work, an open Radio Access Network (RAN), compatible, scalable and highly flexible Software Defined Radio (SDR)-based Remote Radio Head (RRH) framework is proposed and designed. Such framework can be used to implement flexible wideband radio solutions, which can be deployed in any region, have common radio management features, and support various channel bandwidths. Moreover, it enables easier access for researchers to nonsimulated cellular networks, reduce system development time, provide test and measurement capabilities, and support existing and emerging wireless communication technologies. The performance of the proposed SDR framework is validated by creating a Network-in-a-Box (NIB) that can operate in multiband multicarrier 4G or 5G standalone (SA) configurations, with an output power of up to 33 dBm. Measurement results show, that the 4G and 5G NIB can achieve, respectively, up to 883 Mbps and 765 Mbps downlink data transfer speeds for a 100 MHz aggregated bandwidth. However, if six carriers are used in the 4G NIB, 1062 Mbps downlink data transfer speed can be achieved. When single user equipment (UE) is used, maximum uplink data transfer speed is 65.8 Mbps and 92.6 Mbps in case of 4G and 5G, respectively. The average packet latency in case of 5G is up to 45.1% lower than 4G. CPU load by the eNodeB and gNodeB is proportional to occupied bandwidth, but under the same aggregated DL bandwidth conditions, gNodeB load on the CPU is lower. Moreover, if only 1 UE is active, under same aggregated bandwidth conditions, the EPC CPU load is up to four times lower than the 5GC.

8 January 2019 in Electronics
Verified
Journal Article
Open access
PDF file
VMVytautas Macaitis
Vytautas Macaitis
Romualdas NavickasRomualdas Navickas
Romualdas Navickas
This paper presents the design, simulation, and measurements of a low power, low phase noise 10.25–11.78 GHz LC digitally controlled oscillator (LC DCO) with extended true single phase clock (E-TSPC) frequency divider in 130 nm complementary metal–oxide–semiconductor (CMOS) technology for 5G intelligent transport systems. The main goal of this work was to design the LC DCO using a mature and low-cost 130 nm CMOS technology. The designed integrated circuit (IC) consisted of two parts: the LC DCO frequency generation and division circuit and an independent frequency divider testing circuit. The proposed LC DCO consisted of the following main blocks: the high Q-factor inductor, switched-capacitors block, cross-coupled transistors, and the current control block. Inductors with switched-capacitors block formed an LC tank. The designed E-TSPC frequency divider consisted of eight blocks connected in a series; each block increased the division ratio by a factor of two. The frequency of the input signal was divided in the region from two to 256 times using the designed divider. The main parameters of the designed E-TSPC divider and the LC DCO measurements were given as follows: LC DCO achieved a wide tuning range from 10.25 GHz to 11.78 GHz (1.53 GHz, 15.28% bandwidth); phase noise at 1 MHz offset frequency from LC DCO lowest carrier frequency was −113.42 dBc/Hz; phase noise at 1 MHz offset frequency from LC DCO highest carrier frequency was −110.51 dBc/Hz; The average power consumption of the designed LC DCO core and E-TSPC divider were 10.02 mW and 97.52 mW, respectively; the figure of merit (FOM) and the extended FOMT values of the proposed LC DCO were −183.52 dBc/Hz and −187.20 dBc/Hz, respectively. These FOM and FOMT results were achieved due to very low phase noise (−113.52 dBc/Hz) and a wide frequency tuning range (15.28%). The total layout area including the pads was 1.5 mm × 1.5 mm, with the largest part of the layout occupied by the proposed LC DCO (193 µm × 311 µm). The largest part of the LC DCO was occupied by the inductor 184 µm × 184 µm. The manufactured chip was packed into a quad flat no-leads (QFN) 20 pads package.

1 August 2019 in Microelectronics Journal
Verified
Journal Article
Closed access
LKLeonid Kladovščikov
Leonid Kladovščikov
Romualdas NavickasRomualdas Navickas
Romualdas Navickas
KKKarolis Kiela
Karolis Kiela

1 January 2021 in Procedia Computer Science
Verified
Journal Article
Open access
MJMarijan Jurgo
Marijan Jurgo
VMVytautas Macaitis
Vytautas Macaitis
KKKarolis Kiela
Karolis Kiela
Romualdas NavickasRomualdas Navickas
Romualdas Navickas

9 September 2019 in IEEE Magnetics Letters
Verified
Journal Article
Closed access
Nerija ZurauskieneNerija Zurauskiene
Nerija Zurauskiene
RDRasuole Lukose (prev. Dirsyte)
Rasuole Lukose (prev. Dirsyte)
SBSaulius Balevicius
Saulius Balevicius
Voitech StankevicVoitech Stankevic
Voitech Stankevic
SKSkirmantas Kersulis
Skirmantas Kersulis
Romualdas NavickasRomualdas Navickas
Romualdas Navickas
Magnetic field sensor based on a manganite/ $\text{Al}_2 \text{O}_3$ -substrate/three-layer graphene structure operating in the range of (0.1-20) T was designed and fabricated. The $\text{La}_0.9 \text{Sr}_0.1 \text{Mn}_1.2 \text{O}_3$ (LSMO) manganite film and graphene layers prepared on the opposite sides of polycrystalline $\text{Al}_2 \text{O}_3$ substrate enabled to scale the effective volume of the device (~0.16 $\text{mm}^2$ ). The combination of two materials - one with positive (graphene) and the other with negative (manganite) magnetoresistive effects - led to a significant increase of the response signal and sensitivity in comparison with individual graphene or manganite sensors. This was achieved by increasing the magnetoresistance ( $MR$ ) of individual manganite and graphene elements. The $MR$ of LSMO was increased by using a special pulsed-injection MOCVD regime based on two precursor sources with tunable vapor supersaturation and growth rate. The $MR$ of three-layer graphene was optimized by changing width/length ratio of rectangular planar configuration and scaling dimensions from millimeters to few hundred micrometers, what resulted in achievement of maximal sensitivity (72 mV/VT) in the range of magnetic flux density of (1-3) T.