Papers by Calvin Artemies Hilario
2020 International Symposium on Antennas and Propagation (ISAP), 2021
This work provides an assessment of TV white space in the UHF band (470-698 MHz), in the Greater ... more This work provides an assessment of TV white space in the UHF band (470-698 MHz), in the Greater Metro Manila Area (GMMA). Radio propagation simulations were performed using Okumura-Hata and Hata-9999 models. Spectrum measurement was done using a portable spectrum analyzer along a single route from Metropolitan Manila to a nearby province. Assessment of TV white space was done by identifying area with field strength values less than the FCC’s Grade B contour threshold. On the other hand, FCME algorithm was used to identify white spaces from the spectrum measurement data. Results show that there are white spaces in the GMMA, especially outside Metropolitan Manila which can be utilized for secondary use.
2020 IEEE Global Humanitarian Technology Conference (GHTC), 2020
The Philippines, being one of the most disaster-stricken countries in the world, is susceptible t... more The Philippines, being one of the most disaster-stricken countries in the world, is susceptible to property and infrastructure damage caused by natural calamities. During these times, most of the major telecommunication network infrastructures in the affected area become unusable. Thus, developing a robust, low-power, decentralized emergency communication network becomes necessary in order to coordinate the emergency response and relief efforts. In this paper, we propose a mesh network based on LoRa technology as a viable emergency communication tool. We implement a modified ad hoc on-demand distance vector (AODV) routing protocol to enable mesh networking in LoRa. The modified AODV uses the received signal strength indicator (RSSI) as the routing metric. The performance of the proposed system was evaluated based on the packet delivery ratio (PDR). We demonstrate the feasibility of the developed system by transmitting text messages from one mobile phone to another through LoRa-based mesh network.
2019 IEEE International Symposium on Dynamic Spectrum Access Networks (DySPAN), 2019
In this paper, we present the quantitative results of a spectrum measurement campaign for the UHF... more In this paper, we present the quantitative results of a spectrum measurement campaign for the UHF TV band (470 -698 MHz) in the western segment of the Philippine Nautical Highway System (PNHS). The PNHS, also known as the Road Roll-On/Roll-Off Terminal System (RRTS) or Ro-Ro System, is an integrated linkage of inland highways and ferry routes forming a nationwide vehicle transport system in the Philippines that served approximately 77 million passengers in 2018. We used a portable spectrum measurement equipment to gather data in fixed inland, mobile inland, and mobile maritime environments of the Western Philippine Nautical Highway (W-PNH). To characterize and quantify white space, we adopted calculated thresholding using the 80% method (ITU-R SM.1753). We compare the results obtained from the field measurements to that of using the geo-location database approach (FCC method). A discussion on the implication of the available TV spectrum to maritime vehicular communication and pertin...
2021 International Symposium on Antennas and Propagation (ISAP), 2021
The Science4cast Competition consists of predicting new links in a semantic network, with each no... more The Science4cast Competition consists of predicting new links in a semantic network, with each node representing a concept and each edge representing a link proposed by a paper relating two concepts. This network contains information from 1994-2017, with a discretization of days (which represents the publication date of the underlying papers). Team Hash Brown's final submission, ee5a, achieved a score of 0.92738 on the test set. Our team's score ranks second place, 0.01 below the winner's score. This paper details our model, its intuition, and the performance of its variations in the test set.
In the Philippines, several projects had been implemented which gives people living in remote are... more In the Philippines, several projects had been implemented which gives people living in remote areas access to the internet. Some of these projects face geographic problems like remote coastal areas separated by mountains, which leads to the use of expensive Very Small Aperture Terminal. One possible solution is using an ocean long-range wireless communication link buoy as a relay station. However, this faces challenges such as high fading due to the reflection of sea surface and the effects of ocean activities. To address this, a mechanical antenna stabilizer for an omnidirectional antenna is used to compensates the angular movement of the buoy.
IEEE Global Humanitarian Technology Conference (GHTC 2014), 2014
Landslides pose serious threat in a large number of communities living near steep and unstable sl... more Landslides pose serious threat in a large number of communities living near steep and unstable slopes in the Philippines. This paper describes the enhancements in the design of an alternative instrumentation for monitoring deep-seated landslides based on tilt and soil moisture sensors. The real time landslide monitoring system is composed of a sensor column buried in a borehole, which can reach up to 40m in depth, in the unstable slope. Each column consists of 0.5-1m segments that contain a tri-axial accelerometer for tilt measurements and a capacitive sensor for soil moisture. In this manner, tilt and soil moisture measurements can be made at a resolution of 0.5 to 1m underground. Sensor measurements from each segment are accessed via Controller Area Network (CAN) protocol and transmitted to a remote host via GSM cellular infrastructure. We also describe the previous deployments in ten different sites in the Philippines as well as share the technical challenges and difficulties faced in deploying the monitoring system in real world setting. The field deployments provided valuable inputs regarding improvements in the sensor design. Furthermore, this paper discusses the experiences in involving the community at risk as part of the synergistic approach in taking progressive steps towards an effective community and technology based early warning system.
2011 IEEE Global Humanitarian Technology Conference, 2011
This paper describes the development and real-world deployment of an alternative instrumentation ... more This paper describes the development and real-world deployment of an alternative instrumentation for monitoring slope deformation and water level intended as an early warning system for landslides and slope failures. The landslide monitoring system is composed of a "sensor column" that is buried vertically underground in a borehole. The sensor column consists of pipe segments each containing tri-axial accelerometers for
2020 IEEE Global Humanitarian Technology Conference (GHTC), 2020
In this paper, we present the case for opening up the 600 MHz spectrum for use by community-based... more In this paper, we present the case for opening up the 600 MHz spectrum for use by community-based cellular networks (CCN) offering LTE service to unserved and underserved populations in the Philippines. To this end, spectrum measurements were conducted at different locations in the country to establish a measure of utilization or occupancy of the UHF TV spectrum, specifically in the 600 MHz band. Our results show significant white space in the UHF TV band in rural areas, which opens the possibility for the reallocation or re-purposing of this spectrum for mobile networks to provide Internet connectivity in said regions. The 3rd Generation Partnership Project (3GPP), in particular, supports operation of the 4G wireless communications standard, Long Term Evolution or LTE, in the 600 MHz band through Band 71 (617-698 MHz), which is currently not adopted in the Philippines. With policy reform in mind, we have developed an LTE base station prototype, LokaLTE, that supports the case for o...
2019 6th International Conference on Space Science and Communication (IconSpace)
This work presents the development and implementation of a satellite telemetry and telecommand sy... more This work presents the development and implementation of a satellite telemetry and telecommand system in a software defined radio platform and a virtual instrumentation environment. The performance of different modulation and coding schemes under the effects of various channel impairments in satellite communication such as the Additive White Gaussian Noise and Doppler frequency shift were presented through simulations. The system was realized in a software defined radio platform and the performance was verified through actual tests emulating a satellite and ground station communication. The results of the simulations and actual tests show the capability and versatility of the software defined radio - based satellite telemetry and telecommand system and its potential application in building a fully reconfigurable ground station.
IEEE Region 10 Conference, 2018
Propagation in maritime environment dynamically change due to the direct impact of ocean wave und... more Propagation in maritime environment dynamically change due to the direct impact of ocean wave undulation to the antenna position and orientation. This paper presents an approach in characterizing signal propagation in a maritime environment by replicating ocean wave-induced antenna motions in a semi-anechoic chamber. The proposed setup may also be used to test mismatch and misalignment mitigating techniques in a controlled environment. The effect on the received signal power of angular motions such as roll, and pitch due to ocean wave undulation, which causes polarization mismatch and antenna misalignment, were investigated in this study. Different setup configurations were applied by varying the tilting orientation, tilting period and tilting range of the antenna in order to replicate various sea state conditions. Measurements reveal the extent of signal degradation due to polarization mismatch and antenna misalignment, and how received signal power degrades with the tilting range. Signal power deviation was measured to reach up to 3 dB and signal power was measured to swing up to 10dB.
2017 IEEE Conference on Antenna Measurements & Applications (CAMA)
2019 IEEE Global Humanitarian Technology Conference (GHTC)
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Papers by Calvin Artemies Hilario