Guzman, B. G., Cespedes, M. M., Jimenez, V. P. G., Armada, A. G., & Brandt-Pearce, M. (2024). Resource allocation exploiting reflective surfaces to minimize the outage probability in VLC.
@unpublished{guzman2024resource,
title = {Resource allocation exploiting reflective surfaces to minimize the outage probability in VLC},
author = {Guzman, Borja Genoves and Cespedes, Maximo Morales and Jimenez, Victor P. Gil and Armada, Ana Garcia and Brandt-Pearce, Maite},
year = {2024},
eprint = {2401.16627},
archiveprefix = {arXiv},
primaryclass = {eess.SP},
doi = {2401.16627}
}
Journal papers
Fonseca, D. F., Mir, M. S., de Frutos, S. I., Guzman, B. G., & Giustiniano, D. (2024). Modulating LiFi for dual operation in the visible and infrared spectra. Computer Communications.
@article{FONSECA2024,
title = {Modulating LiFi for dual operation in the visible and infrared spectra},
journal = {Computer Communications},
file = {FONSECA2024.pdf},
year = {2024},
issn = {0140-3664},
doi = {https://doi.org/10.1016/j.comcom.2024.01.005},
author = {Fonseca, Dayrene Frometa and Mir, Muhammad Sarmad and {de Frutos}, Sergio Iglesias and Guzman, Borja Genoves and Giustiniano, Domenico},
keywords = {Dimming, Infrared (IR) spectrum, LiFi, Visible light (VL) spectrum}
}
Light-Fidelity (LiFi) has emerged in the last few years as a promising technology for alleviating the stringent demand for wireless data services. Prior works have considered LiFi operating either in the visible light or infrared spectrum. Each spectrum band has its own advantages: visible light allows leveraging existing infrastructure for communication, while infrared is not affected by light dimming. In this work, we propose a modulation scheme that retains the benefits of both bands, introducing a simple, low-cost, yet efficient dimming solution for LiFi networks. We compare the performance of the proposed dimming scheme with both the digital and analog dimming techniques traditionally used in LiFi systems. Simulation results show that our dimming solution offers better communication and illumination performance than previous proposals, providing larger signal-to-noise ratio, spectral efficiency, and a full and fine-grained dimming range. Finally, we prototype our solution by designing an extended version of the OpenVLC 1.3 platform, and we experimentally show its robust communication performance under different dimming conditions. We make the implemented system publicly available to the research community.
A prediction-model-assisted reinforcement learning algorithm for handover decision-making in hybrid LiFi and WiFi networks. (2023). Journal of Optical Communications and Networking.
@article{JOCN2023,
author = {},
journal = {Journal of Optical Communications and Networking},
title = {A prediction-model-assisted reinforcement learning algorithm for handover decision-making in hybrid LiFi and WiFi networks},
file = {JOCN_Dspace.pdf},
year = {2023},
volume = {},
number = {},
doi = {10.1364/JOCN.495234}
}
The handover process in hybrid light fidelity (LiFi) and wireless fidelity (WiFi) networks (HLWNets) is very challenging due to the short area covered by LiFi access points and the coverage overlap between LiFi and WiFi networks, which introduce frequent horizontal and vertical handovers, respectively. Different handover schemes have been proposed to reduce the handover rate in HLWNets, among which handover skipping (HS) techniques stand out. However, existing solutions are still inefficient or require knowledge that is not available in practice, such as the exact user’s trajectory or the network topology. In this work, a novel machine learning-based handover scheme is proposed to overcome the limitations of previous HS works. Specifically, we have designed a classification model to predict the type of user’s trajectory and assist a reinforcement learning (RL) algorithm to make handover decisions that are automatically adapted to new network conditions. The proposed scheme is called RL-HO, and we compare its performance against the standard handover scheme of long-term evolution (STD-LTE) and the so-called smart handover (Smart HO) algorithm. We show that our proposed RL-HO scheme improves the network throughput by 146% and 59% compared to STD-LTE and Smart HO, respectively. We make our simulator code publicly available to the research community.
Guzmán, B. G., Mir, M. S., Fonseca, D. F., Galisteo, A., Wang, Q., & Giustiniano, D. (2023). Prototyping Visible Light Communication for the Internet of Things Using OpenVLC. IEEE Communications Magazine.
@article{VLCPrototyping,
author = {Guzmán, Borja Genovés and Mir, Muhammad Sarmad and Fonseca, Dayrene Frómeta and Galisteo, Ander and Wang, Qing and Giustiniano, Domenico},
title = {Prototyping Visible Light Communication for the Internet of Things Using OpenVLC},
journal = {IEEE Communications Magazine},
file = {VLCPrototyping.pdf},
year = {2023},
doi = {10.1109/MCOM.001.2200642}
}
Visible Light Communication (VLC) has emerged in the last few years as a promising technology not only for high-speed communication but also for serving a new generation of Internet of Things (IoT) devices that may leverage the pervasive lighting infrastructures. Integrating VLC in lighting environments for IoT requires the design of networked and intelligent luminaries and new IoT devices, encompassing the development of innovative technologies and new algorithms. A common experimental platform is necessary to lower the entrance barriers of VLC and speed up the research development. In this paper, we provide guidelines for prototyping VLC for IoT applications, assisted by the open-source platform OpenVLC. We also introduce the new development on OpenVLC, which guarantees support for more powerful LEDs and much longer distance (extending the communication distance from 6 m to 19 m), dimming adaption, among other features. Its low-cost, open-source, and open-hardware designs allow researchers in the community to swiftly adapt it to suit their research purposes.
Guzmán, B. G., Talavante, J., Fonseca, D. F., Mir, M. S., Giustiniano, D., Obraczka, K., Loik, M. E., Childress, S., & Wong, D. G. (2023). Towards sustainable greenhouses using battery-free LiFi-enabled Internet of Things. IEEE Communications Magazine.
@article{LiFiGreenhouse,
author = {Guzmán, Borja Genovés and Talavante, Javier and Fonseca, Dayrene Frómeta and Mir, Muhammad Sarmad and Giustiniano, Domenico and Obraczka, Katia and Loik, Michael E. and Childress, Sylvie and Wong, Darryl G.},
title = {Towards sustainable greenhouses using battery-free LiFi-enabled Internet of Things},
journal = {IEEE Communications Magazine},
file = {LiFiGreenhouse.pdf},
year = {2023},
doi = {10.1109/MCOM.001.2200489}
}
As the world faces a changing climate, agriculture needs to develop more efficient and sustainable food production systems. Traditional farming methods consume considerable amounts of energy and are largely manually controlled, which leads to sub-optimal production. Greenhouses, which enable year-round crop growth, can play an important role in efficient food production. Leveraging the need for artificial light in greenhouses when the natural sunlight available is not sufficient, we envision that recent progress in Internet of Things (IoT) technology, together with novel Light-Fidelity (LiFi)-based methods have the potential to significantly reduce energy and resources used in food production. In this paper we describe our work towards sustainable and precision greenhouses by using LiFi-enabled IoT. Here we present a battery-free wireless network of IoT sensor nodes that exploit LiFi for both communication and power harvesting, while monitoring environmental conditions for optimal greenhouse operation and plant production. We highlight the research challenges and the way forward to integrate LiFi to monitor and control greenhouses, as well as a proof-of-concept LiFi-enabled IoT system for a real-world greenhouse.
Céspedes, M. M., Guzmán, B. G., Gil Jiménez, V. P., & Armada, A. G. (2023). Aligning the Light for Vehicular Visible Light Communications: High Data Rate and Low-Latency Vehicular Visible Light Communications Implementing Blind Interference Alignment. IEEE Vehicular Technology Magazine, 18(1), 59–69.
@article{10015891,
author = {Céspedes, Máximo Morales and Guzmán, Borja Genovés and Gil Jiménez, Víctor P. and Armada, Ana García},
journal = {IEEE Vehicular Technology Magazine},
title = {Aligning the Light for Vehicular Visible Light Communications: High Data Rate and Low-Latency Vehicular Visible Light Communications Implementing Blind Interference Alignment},
year = {2023},
volume = {18},
number = {1},
pages = {59-69},
doi = {10.1109/MVT.2022.3228389}
}
Vehicle-to-vehicle (V2V) communications are one of the most promising 6G scenarios. However, V2V communications demand high data rates and extremely low-latency requirements that are difficult to satisfy nowadays. Recently, vehicular visible light communications (V-VLC) have been proposed as a promising technology to guarantee such requirements. Multiple-input, multiple-output (MIMO) techniques can potentially achieve high data rates. However, when applied to V-VLC, they confront challenges such as the latency because of the need for closed-loop transmission or the correlation among optical channel responses. This article explains the use of blind interference alignment (BIA) for V-VLC based on the concept of a reconfigurable photodetector to provide linearly independent channel responses. It is shown that BIA solves the issues of MIMO techniques and may comply with the 6G V-VLC requirements. Besides, the vehicles are a convenient platform for implementing a reconfigurable photodetector. Finally, the open issues for BIA implementation in V-VLC are discussed to inspire future research.
Mir, M. S., Guzman, B. G., Varshney, A., & Giustiniano, D. (2023). LiFi for Low-Power and Long-Range RF Backscatter. IEEE/ACM Transactions on Networking, 1–16.
@article{TNET2023,
author = {Mir, Muhammad Sarmad and Guzman, Borja Genoves and Varshney, Ambuj and Giustiniano, Domenico},
journal = {IEEE/ACM Transactions on Networking},
title = {LiFi for Low-Power and Long-Range RF Backscatter},
file = {AuthorsVersionTNET.pdf},
year = {2023},
volume = {},
number = {},
pages = {1-16},
doi = {10.1109/TNET.2023.3344316}
}
Light bulbs have been recently explored to design Light Fidelity (LiFi) communication to battery-free tags, thus complementing Radiofrequency (RF) backscatter in the uplink. In this paper, we show that LiFi and RF backscatter are complementary and have unexplored interactions. We introduce, a battery-free system that uses LiFi to transmit RF backscatter at a meagre power budget. We address several challenges on the system design in the LiFi transmitter, the tag and the RF receiver. We design the first LiFi transmitter that implements a chirp spread spectrum (CSS) using the visible light spectrum. We use a small bank of solar cells for both communication and harvesting, and reconfigure them based on the amount of harvested energy and desired data rate. We further alleviate the low responsiveness of solar cells with a new low-power receiver design in the tag. We design and implement a novel technique for embedding multiple symbols in the RF backscatter based on delayed chirps. Experimental results with an RF carrier of 17 dBm show that we can generate RF backscatter with a range of 92.1 meters/ μ W consumed in the tag, which is almost double with respect to prior work.
Dowhuszko, A. A., & Guzmán, B. G. (2022). Closed Form Approximation of the Actual Spectral Power Emission of Commercial Color LEDs for VLC. Journal of Lightwave Technology, 40(13), 4311–4320.
@article{9732203,
author = {Dowhuszko, Alexis A. and Guzmán, Borja Genovés},
journal = {Journal of Lightwave Technology},
title = {Closed Form Approximation of the Actual Spectral Power Emission of Commercial Color LEDs for VLC},
year = {2022},
volume = {40},
number = {13},
pages = {4311-4320},
keywords = {},
doi = {10.1109/JLT.2022.3158188},
issn = {1558-2213},
month = jul,
file = {JLT_dowhu_Camera_Ready_07032022.pdf}
}
Multi-color Light-Emitting Diode (LED) technology enables a simple approach to increase the throughput of a Visible Light Communications (VLC) system, by using Wavelength-Division Multiplexing (WDM) to transmit independent data streams on different colors. However, to compute the data rate that is achievable in such WDM VLC link, the optical power that leaks between the different colors needs to be estimated accurately, especially when low-cost optical filters are used in reception. So far, the approximations that have been reported in the literature to model the spectral power emission of different color LEDs are not good enough to perform these calculations. Starting from the theoretical spectral emission of a color LED, a closed form expression is derived based on an asymmetric Pearson type VII function, which is shown to approximate accurately the measured spectra of the color LEDs at different working regimes. In addition, the effect that the DC-bias current has on the key parameters of the approximated spectral power emissions, namely the peak and half-maximum wavelengths, as well as the peak spectral emission, are studied. Finally, a new approach is proposed to assess the level of fitness of the derived closed form approximations, using for this purpose the step-size of the MacAdam ellipses that corresponds to the different color LED spectral emissions in the CIE 1931 chromaticity diagram.
Céspedes, M. M., Guzmán, B. G., & Jiménez, V. P. G. (2021). Lights and Shadows: A Comprehensive Survey on Cooperative and Precoding Schemes to Overcome LOS Blockage and Interference in Indoor VLC. Sensors, 21(3).
@article{s21030861,
author = {Céspedes, Máximo Morales and Guzmán, Borja Genovés and Jiménez, Víctor P. Gil},
title = {Lights and Shadows: A Comprehensive Survey on Cooperative and Precoding Schemes to Overcome LOS Blockage and Interference in Indoor VLC},
journal = {Sensors},
volume = {21},
year = {2021},
number = {3},
article-number = {861},
pubmedid = {33525373},
issn = {1424-8220},
file = {LightsAndShadows.pdf},
doi = {10.3390/s21030861}
}
Visible light communications (VLC) have received significant attention as a way of moving part of the saturated indoor wireless traffic to the wide and unregulated visible optical spectrum. Nowadays, VLC are considered as a suitable technology, for several applications such as high-rate data transmission, supporting internet of things communications or positioning. The signal processing originally derived from radio-frequency (RF) systems such as cooperative or precoding schemes can be applied to VLC. However, its implementation is not straightforward. Furthermore, unlike RF transmission, VLC present a predominant line-of-sight link, although a weak non-LoS component may appear due to the reflection of the light on walls, floor, ceiling and nearby objects. Blocking effects may compromise the performance of the aforementioned transmission schemes. There exist several surveys in the literature focused on VLC and its applications, but the management of the shadowing and interference in VLC requires a comprehensive study. To fill this gap, this work introduces the implementation of cooperative and precoding schemes to VLC, while remarking their benefits and drawbacks for overcoming the shadowing effects. After that, the combination of both cooperative and precoding schemes is analyzed as a way of providing resilient VLC networks. Finally, we propose several open issues that the cooperative and precoding schemes must face in order to provide satisfactory VLC performance in indoor scenarios.
Guzmán, B. G., Dowhuszko, A. A., Jiménez, V. P. G., & Pérez-Neira, A. I. (2020). Resource Allocation for Cooperative Transmission in Optical Wireless Cellular Networks With Illumination Requirements. IEEE Transactions on Communications, 68(10), 6440–6455.
@article{9144514,
author = {Guzmán, Borja Genovés and Dowhuszko, Alexis A. and Jiménez, Víctor P. Gil and Pérez-Neira, Ana I.},
journal = {IEEE Transactions on Communications},
title = {Resource Allocation for Cooperative Transmission in Optical Wireless Cellular Networks With Illumination Requirements},
year = {2020},
volume = {68},
number = {10},
pages = {6440-6455},
keywords = {},
doi = {10.1109/TCOMM.2020.3010583},
issn = {1558-0857},
month = oct,
file = {TCOM2020.pdf}
}
Visible light communication (VLC) often suffers from line-of-sight path blockages and high levels of inter-cell interference. Thus, the analysis and design of cooperation techniques become crucial to address these key impairments. This paper studies the performance of different resource allocation schemes that are suitable for multi-cell cooperative transmission when tri- and tetra-chromatic light-emitting diodes (LEDs) and optical orthogonal frequency-division multiple access are utilized. Firstly, guidelines are derived for maintaining the same spatial distribution of the signal-to-interference-plus-noise ratio (SINR) in every sector of the multi-cell environment in case of stand-alone (non-cooperative) and cooperative transmission. Secondly, the possible resource allocation configurations for both stand-alone and cooperative transmission modes are identified for different LED types and available orthogonal resources (i.e., frequency sub-bands per color and sectors per cell). Finally, the data rate gain of the multiple resource allocation configurations are also analyzed, while verifying the illumination constraints. The obtained results confirm that the proper design of cooperative transmission configurations will be of paramount importance to provide reliable wireless link in ultra-dense VLC deployments.
Guzmán, B. G., Chen, C., Jiménez, V. P. G., Haas, H., & Hanzo, L. (2020). Reflection-Based Relaying Techniques in Visible Light Communications: Will it Work? IEEE Access, 8, 80922–80935.
@article{9079516,
author = {Guzmán, Borja Genovés and Chen, Cheng and Jiménez, Víctor P. Gil and Haas, Harald and Hanzo, Lajos},
journal = {IEEE Access},
title = {Reflection-Based Relaying Techniques in Visible Light Communications: Will it Work?},
year = {2020},
volume = {8},
number = {},
pages = {80922-80935},
keywords = {},
doi = {10.1109/ACCESS.2020.2990660},
issn = {2169-3536},
month = {},
file = {reflectionbased_genovesguzman.pdf}
}
Visible light communication (VLC) is capable of satisfying the escalating data rate demand in indoor scenarios. The lighting infrastructure may also be exploited in the downlink of a wireless local area network (WLAN), where light-emitting diodes are used for transmitting information. The backhaul of VLC access points (APs) constitutes a potential bottleneck in WLANs, especially in large rooms where the number of APs is high. Thus, an alternative reflection-based cooperative wireless system concept is proposed, where no wired connections are required for connecting the APs. Then, its data rate analysis is developed based on the signal-to-noise ratio attained. The results show that the performance of the cooperative wireless system advocated closely approximates the performance of the traditional wired backhaul. Finally, we demonstrate by using Jain’s index of fairness that the proposed scheme provides fair coverage quality for all users.
Estrada-Jiménez, J. C., Guzmán, B. G., Fernández-Getino García, M. J., & Jiménez, V. P. G. (2019). Superimposed Training-Based Channel Estimation for MISO Optical-OFDM VLC. IEEE Transactions on Vehicular Technology, 68(6), 6161–6166.
@article{8681400,
author = {Estrada-Jiménez, Juan Carlos and Guzmán, Borja Genovés and Fernández-Getino García, M. Julia and Jiménez, Víctor P. Gil},
journal = {IEEE Transactions on Vehicular Technology},
title = {Superimposed Training-Based Channel Estimation for MISO Optical-OFDM VLC},
year = {2019},
volume = {68},
number = {6},
pages = {6161-6166},
keywords = {},
doi = {10.1109/TVT.2019.2909428},
issn = {1939-9359},
month = jun,
file = {Superimposed_IEEETVT_2019_ps.pdf}
}
In this paper, we investigate a novel channel estimation (CE) method for multiple-input and single-output (MISO) systems in visible light communication (VLC). Direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) is commonly used in VLC where half of the available subcarriers are spent to guarantee a real-valued output after the inverse fast Fourier transform operation. Besides, dedicated subcarriers are typically used for CE, thus, many resources are wasted and the spectral efficiency is degraded. We propose a superimposed training approach for CE in MISO DCO-OFDM VLC scenarios. Analytical expressions of mean squared error (MSE) and spectral efficiency are derived when the least squares estimator is considered. This analysis is valid for outdoor and indoor scenarios. For the CE error, simulation results of MSE show a perfect match with analytical expressions. Moreover, results prove that this technique guarantees a larger spectral efficiency than previous schemes where dedicated pilots were used. Finally, the optimal data power allocation factor is also analytically derived.
Genovés Guzmán, B., Dowhuszko, A. A., Gil Jiménez, V. P., & Pérez-Neira, A. I. (2018). Robust Cooperative Multicarrier Transmission Scheme for Optical Wireless Cellular Networks. IEEE Photonics Technology Letters, 30(2), 197–200.
@article{8169113,
author = {Genovés Guzmán, Borja and Dowhuszko, Alexis A. and Gil Jiménez, Víctor P. and Pérez-Neira, Ana I.},
journal = {IEEE Photonics Technology Letters},
title = {Robust Cooperative Multicarrier Transmission Scheme for Optical Wireless Cellular Networks},
year = {2018},
volume = {30},
number = {2},
pages = {197-200},
keywords = {},
doi = {10.1109/LPT.2017.2781184},
issn = {1941-0174},
month = jan,
file = {Robust_IEEEPTL_2018_ps.pdf}
}
Visible light communication (VLC) is a promising technology to achieve high data rates in heterogeneous scenarios. However, VLC strongly depends on the existence of a line-of-sight (LoS) link between transmitter and receiver to guarantee a good data rate performance, which is often a condition that is difficult to satisfy in practice. In this letter, a novel cooperative multicarrier transmission scheme is proposed, where neighboring attocells smartly cooperate to decrease the probability of blockage in the LoS link. This approach is compared to single-cell transmission schemes, obtaining notable gains in both received signal-to-interference-plus-noise ratio and cell data rate when blockage of the LoS link occurs toward the nearest base station.
Genovés Guzmán, B., Gil Jiménez, V. P., Aguayo-Torres, M. C., Haas, H., & Hanzo, L. (2018). Downlink Performance of Optical OFDM in Outdoor Visible Light Communication. IEEE Access, 6, 76854–76866.
@article{8543148,
author = {Genovés Guzmán, Borja and Gil Jiménez, Víctor P. and Aguayo-Torres, Mari Carmen and Haas, Harald and Hanzo, Lajos},
journal = {IEEE Access},
title = {Downlink Performance of Optical OFDM in Outdoor Visible Light Communication},
year = {2018},
volume = {6},
number = {},
pages = {76854-76866},
keywords = {},
doi = {10.1109/ACCESS.2018.2882919},
issn = {2169-3536},
month = {},
file = {Downlink_IEEEA_2018.pdf}
}
Visible light communication (VLC) is a promising ubiquitous design alternative for supporting high data rates. Its application has been primarily oriented to indoor scenarios, but the proliferation of light-emitting diodes in the streets warrants its investigation in outdoor scenarios as well. This paper studies the feasibility of VLC in a conventional outdoor scenario, when optical orthogonal frequency division multiplexing techniques are employed. The presence of sunlight reduces the system’s performance, hence sophisticated adaptive techniques must be applied. Closed-form expressions of the signal-to-noise ratio and of the mean cell data rate are derived and our simulations demonstrate their accuracy. Besides, the outage probability when adaptive modulation and coding schemes are employed is analytically expressed. It is shown that, when modulation bandwidth adaptation is carried out depending on the time of day and the illuminance from ambient light, the mean cell data rate is increased and the outage probability is reduced.
Genovés Guzmán, B., & Gil Jiménez, V. P. (2017). DCO-OFDM Signals With Derated Power for Visible Light Communications Using an Optimized Adaptive Network-Based Fuzzy Inference System. IEEE Transactions on Communications, 65(10), 4371–4381.
@article{7967676,
author = {Genovés Guzmán, Borja and Gil Jiménez, Víctor P.},
journal = {IEEE Transactions on Communications},
title = {DCO-OFDM Signals With Derated Power for Visible Light Communications Using an Optimized Adaptive Network-Based Fuzzy Inference System},
year = {2017},
volume = {65},
number = {10},
pages = {4371-4381},
keywords = {},
doi = {10.1109/TCOMM.2017.2722477},
issn = {1558-0857},
month = oct,
file = {DCO-OFDM_IEEETC_2017_ps.pdf}
}
Direct current-biased optical orthogonal frequency division multiplexing (DCO-OFDM) signals used in visible light communications suffer from high peak-to-average-power ratio (PAPR) or cubic metric (CM). It strongly degrades the performance due to the great back-off necessary to avoid the clipping effect in the light-emitting diode. Thus, PAPR and CM reduction techniques become crucial to improve the system performance. In this paper, an adaptive network-based fuzzy inference system (ANFIS) is used to obtain efficient DCO-OFDM signals with a low power envelope profile. First, signals specially designed for DCO-OFDM with very low CM, as the ones obtained from the raw cubic metric (RCM)-active constellation extension method, are used to train the fuzzy systems in time and frequency domains. Second, after the off-line training, the ANFIS can generate a real-valued signal in a one-shot way with 8.9 dB of RCM reduction from the original real-valued signal, which involves a gain in the input power back off larger than 2.8 dB, an illumination-to-communication conversion efficiency gain of more than 35% and considerable improvements in bit error rate.
Jimenez, V. P. G., Serrano, A. L., Guzman, B. G., & Armada, A. G. (2017). Learning Mobile Communications Standards through Flexible Software Defined Radio Base Stations. IEEE Communications Magazine, 55(5), 116–123.
@article{7926928,
author = {Jimenez, Victor P. Gil and Serrano, Alejandro Lancho and Guzman, Borja Genoves and Armada, Ana Garcia},
journal = {IEEE Communications Magazine},
title = {Learning Mobile Communications Standards through Flexible Software Defined Radio Base Stations},
year = {2017},
volume = {55},
number = {5},
pages = {116-123},
keywords = {},
doi = {10.1109/MCOM.2017.1601219},
issn = {1558-1896},
month = may,
file = {Mobile_IEEECM_2017_ps.pdf}
}
Mobile communications are today widespread and contribute to the development of our society. Every day new devices include some means of wireless transmission, which is becoming ubiquitous with the Internet of Things. These systems are standardized by international organizations such as the IEEE, 3GPP, and ETSI, among others. Even though knowledge of wireless standards is key to the understanding of these systems, wireless communications are quite often taught in engineering degrees in a traditional way, without much emphasis on the standardization. Moreover, strong focus is often placed on the theoretical performance analysis rather than on practical implementation aspects. In contrast, most of the current applications make extensive use of mobile data, and the global users’ satisfaction is highly correlated with the mobile data throughput. Thus, modern wireless engineers need to have deep insight on the standards that define the mobile transmission systems, and this knowledge is not acquired following the traditional theoretical teaching schemes. In this article, a new learning approach is described. This novel paradigm is based on a new flexible hardware/software platform (FRAMED-SOFT), which is also detailed. Although the article is focused on two wireless standards, GSM and UMTS, the work discussed in this article can easily be extended to other standards of interest, such as LTE and beyond, WiFi, and WiMAX.
Guzman, B. G., Serrano, A. L., & Gil Jimenez, V. P. (2015). Cooperative optical wireless transmission for improving performance in indoor scenarios for visible light communications. IEEE Transactions on Consumer Electronics, 61(4), 393–401.
@article{7389772,
author = {Guzman, Borja Genoves and Serrano, Alejandro Lancho and Gil Jimenez, Víctor P.},
journal = {IEEE Transactions on Consumer Electronics},
title = {Cooperative optical wireless transmission for improving performance in indoor scenarios for visible light communications},
year = {2015},
volume = {61},
number = {4},
pages = {393-401},
keywords = {},
doi = {10.1109/TCE.2015.7389772},
issn = {1558-4127},
month = nov,
file = {Wireless_IEEETCE_2015_ps.pdf}
}
In this paper, a novel cooperative transmission and reception scheme in Visible Light Communications (VLC) is proposed and evaluated. This new scheme provides improvements and reliability in large indoor scenarios, such as corridors, laboratories, shops or conference rooms, where the coverage needs to be obtained by using different access points when VLC is used. The main idea behind the proposal is a simple cooperative transmission scheme where the receiver terminal will obtain the signal from different access points at the same time. This proposal outperforms traditional VLC schemes, especially in Non-Line-of-Sight reception where around 3 dB of gain, with respect to traditional schemes, can be obtained for unoptimized parameters, and larger than 3 dB could easily be achieved. The cooperation is studied in terms of the percentage of light coming from the main access point and a parameter called sidelobes’ amplitude level. The performance is evaluated according to the location within the atto-cell.
Conference papers
Fonseca, D. F., Mir, M. S., Guzman, B. G., & Giustiniano, D. (2023). Visible light or infrared? Modulating LiFi for dual operation in the visible and infrared spectra. 2023 18th Wireless On-Demand Network Systems and Services Conference (WONS), 47–50.
@inproceedings{10061923,
author = {Fonseca, Dayrene Frometa and Mir, Muhammad Sarmad and Guzman, Borja Genoves and Giustiniano, Domenico},
booktitle = {2023 18th Wireless On-Demand Network Systems and Services Conference (WONS)},
title = {Visible light or infrared? Modulating LiFi for dual operation in the visible and infrared spectra},
year = {2023},
volume = {},
number = {},
pages = {47-50},
keywords = {},
doi = {10.23919/WONS57325.2023.10061923},
issn = {},
month = jan
}
Light-Fidelity (LiFi) has emerged in the last few years as a promising technology for alleviating the stringent demand of wireless data services. Prior works have considered LiFi operating either in the visible light or infrared spectrum. Each spectrum band has its own advantages: visible light allows leveraging existing infrastructure for communication, while infrared is not affected by degradation in presence of light dimming. In this work, we propose a modulation scheme that efficiently uses both spectra, and present a simple, low cost, yet efficient modulation technique that retains the benefits of both bands. We prototype our solution by creating an extended version of OpenVLC, and we experimentally show its robust performance in communication under different dimming conditions. We make the implemented system publicly available to the research community.
Fonseca, D. F., Guzman, B. G., Giustiniano, D., & Widmer, J. (2023). A System Architecture for Battery-free IoT Networks. 2023 IEEE 31st International Conference on Network Protocols (ICNP), 1–11.
@inproceedings{ICNP2023,
author = {Fonseca, Dayrene Frometa and Guzman, Borja Genoves and Giustiniano, Domenico and Widmer, Joerg},
booktitle = {2023 IEEE 31st International Conference on Network Protocols (ICNP)},
title = {A System Architecture for Battery-free IoT Networks},
year = {2023},
volume = {},
number = {},
pages = {1-11},
doi = {10.1109/ICNP59255.2023.10355593}
}
While much research effort has been invested in long-range and low-power uplink communication for battery-free IoT networks, current deployments lack a scalable bidirectional communication infrastructure for data collection and processing with battery-free devices. To fill this gap, we introduce Lo W-Fi, a system architecture specifically designed to meet the requirements of battery-free IoT applications. We show the suitability of LoW-Fi for deploying monitoring systems for precision agriculture indoors. This sector is revolutionizing with the installation of smart greenhouses that require the constant monitoring of ambient parameters to ensure optimal conditions for the crops growth. Our system is implemented using commercial off-the-shelf devices, and it works at the intersection of WiFi and LiFi for downlink and RF backscatter for uplink, retaining the advantages of each technology and solving their practical limitations. We evaluate LoW-Fi performance in a real greenhouse, and the experimental results show that it can achieve an uplink (downlink) range of 45m(70m) with 0% BER. The aggregated data rate is up to 4.5 Mb/s.
Mir, M. S., Cui, M., Guzman, B. G., Wang, Q., Xiong, J., & Giustiniano, D. (2023). LeakageScatter: Backscattering LiFi-leaked RF Signals. Proceedings of the Twenty-Fourth International Symposium on Theory, Algorithmic Foundations, and Protocol Design for Mobile Networks and Mobile Computing (ACM Mobihoc), 290–299.
@inproceedings{Mobihoc2023,
author = {Mir, Muhammad Sarmad and Cui, Minhao and Guzman, Borja Genoves and Wang, Qing and Xiong, Jie and Giustiniano, Domenico},
title = {LeakageScatter: Backscattering LiFi-leaked RF Signals},
year = {2023},
isbn = {9781450399265},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
doi = {10.1145/3565287.3610262},
booktitle = {Proceedings of the Twenty-Fourth International Symposium on Theory, Algorithmic Foundations, and Protocol Design for Mobile Networks and Mobile Computing (ACM Mobihoc)},
pages = {290–299},
numpages = {10},
keywords = {implementation, system design, backscatter, leaked RF signals, LiFi},
location = {Washington, DC, USA},
series = {MobiHoc '23}
}
Radio-Frequency (RF) backscatter has emerged as a low-power communication technique. Backscatter systems either rely on active signal generators (spectrum efficient, but dedicated infrastructure) or existing ambient wireless transmissions (existing infrastructure, but spectrum inefficient). In this paper, we aim to make RF backscatter spectrum efficient and at the same time work with existing infrastructure. We propose to leverage the deployment of LiFi networks built upon LED bulbs for pervasive RF backscatter. We experimentally demonstrate that LiFi, which passively leaks RF signals, can be exploited as a radio carrier generator for low-power RF backscatter. We further design LeakageScatter, the first backscatter system operating in the ISM band and exploiting LiFi-leaked RF signals, without the need to actively generate the carrier wave. We customize the design of the loop at the LiFi transmitter, as well as the coil antennas at the tag and RF backscatter receiver, to optimize the system performance. We propose to opportunistically enable the oscillator of the backscatter tag in the software that could reduce the energy consumption on backscattering by up to 75%. Experimental results show that LeakageScatter achieves a backscattering distance up to 10 m and 18 m in indoor and outdoor scenarios, respectively, without using a dedicated RF carrier generator.
Martena, G. L., Sperga, J., Fonseca, D. F., Bian, R., Guzman, B. G., Islim, M. S., Kosman, J., & Haas, H. (2023). A Simulation Tool for Interference Analysis in MIMO Wavelength Division LiFi Indoor Networks. 2023 IEEE International Conference on Communications Workshops (ICC Workshops), 86–91.
@inproceedings{ICC2023,
author = {Martena, Giovanni Luca and Sperga, Janis and Fonseca, Dayrene Frometa and Bian, Rui and Guzman, Borja Genoves and Islim, Mohamed Sufyan and Kosman, John and Haas, Harald},
booktitle = {2023 IEEE International Conference on Communications Workshops (ICC Workshops)},
title = {A Simulation Tool for Interference Analysis in MIMO Wavelength Division LiFi Indoor Networks},
year = {2023},
volume = {},
number = {},
pages = {86-91},
doi = {10.1109/ICCWorkshops57953.2023.10283751}
}
In this paper we propose a novel simulation tool for indoor Light Fidelity (LiFi) networks based on Wavelength Division (WD) with real optical filters characteristics. Firstly we present the measured passband spectra of optical filters, along with a system model validation relying on such acquired spectra. Secondly, we propose a simulation tool developed to extend the work of adaptive wavelength division multiple access to the multiple-input multiple-output case, suitable for conducting Monte Carlo simulations. Then, we validate such tool by considering an example scenario with fixed positions and orientations, including increasing number of users in an indoor LiFi network using WD. In order to better clarify the interference contributions to the quality of service provided, we consider the first user as reference, and evaluate how the presence of progressively higher number of users in its vicinity impacts the interference that the main user is experiencing. We then analyse how the signal-to-interference-plus-noise ratio, interference-to-noise ratio and signal-to-interference ratio figures of the main user change depending on how many interfering users are included in the considered scenario.
Talavante, J., Guzman, B. G., & Giustiniano, D. (2023). Rethinking LiFi for Carbon Neutral Sunlight-based Communication. 2023 21st Mediterranean Communication and Computer Networking Conference (MedComNet), 53–60.
@inproceedings{10168863,
author = {Talavante, Javier and Guzman, Borja Genoves and Giustiniano, Domenico},
booktitle = {2023 21st Mediterranean Communication and Computer Networking Conference (MedComNet)},
title = {Rethinking LiFi for Carbon Neutral Sunlight-based Communication},
year = {2023},
volume = {},
number = {},
pages = {53-60},
doi = {10.1109/MedComNet58619.2023.10168863}
}
Wireless communication has to be redesigned to achieve sustainable communication infrastructure providing net-zero carbon dioxide emission. This paper presents a novel Light Fidelity (LiFi) design that exploits the concept of tubular light guides that can be installed in new buildings. While these guides bring natural sunlight indoors, our proposed system LiFiTube modulates it with low-power liquid crystal (LC) shutters to provide wireless data services without using any power hungry electronic components. Preliminary results show that our proposed LiFiTube system can provide a self-sustainable communication technology and can guarantee demands of Internet of Things networks, while illuminating indoors. We also draw some future research directions.
Guzman, B. G., Cespedes, M. M., Jimenez, V. P. G., Armada, A. G., & Brandt-Pearce, M. (2023). Optimal Mirror Placement to Minimize the Outage Area in Visible Light Communication. GLOBECOM 2023 - 2023 IEEE Global Communications Conference, 4698–4703.
@inproceedings{10436718,
author = {Guzman, Borja Genoves and Cespedes, Maximo Morales and Jimenez, Victor P. Gil and Armada, Ana Garcia and Brandt-Pearce, Maïté},
booktitle = {GLOBECOM 2023 - 2023 IEEE Global Communications Conference},
title = {Optimal Mirror Placement to Minimize the Outage Area in Visible Light Communication},
year = {2023},
volume = {},
number = {},
pages = {4698-4703},
keywords = {Wireless communication;Shape;Line-of-sight propagation;Mirrors;Optimization;Standards;Visible light communication;Line-of-sight (LoS) link blockage;mirrors;optimal placement;outage probability;reconfigurable-intelligent surfaces (RIS);visible light communication (VLC)},
doi = {10.1109/GLOBECOM54140.2023.10436718}
}
Visible light communication (VLC) is a growing technology that can complement radio frequency to fulfill the increasing demand for wireless data services. VLC exploits the already deployed illumination infrastructure based on light-emitting diodes to communicate data. While mirrors have been traditionally used for interior decoration, among other applications, to what extent can they be deployed to improve VLC performance? In this paper, we propose optimizing the placement of mirrors to minimize the outage area, a common problem in VLC when line-of-sight link blockage occurs. We compare this optimal performance with a single-rectangular mirror array, a common mirror shape that is found indoors. We also study the most helpful mirror placement under different conditions. We show that our outage minimization algorithm, MinOut, easily provides threefold outage reductions. Besides, we demonstrate that a single-rectangular mirror array with orientation mobility can provide similar or even better performance than an optimal distributed mirror placement without mobility.
Frometa Fonseca, D., Sarmad Mir, M., Guzman, B. G., Varshney, A., & Giustiniano, D. (2023). PassiveLiFi Demonstration: Rethinking LiFi for Low-Power and Long Range RF Backscatter. Proceedings of the 29th Annual International Conference on Mobile Computing and Networking.
@inproceedings{Mobicom2023,
author = {Frometa Fonseca, Dayrene and Sarmad Mir, Muhammad and Guzman, Borja Genoves and Varshney, Ambuj and Giustiniano, Domenico},
title = {PassiveLiFi Demonstration: Rethinking LiFi for Low-Power and Long Range RF Backscatter},
year = {2023},
isbn = {9781450399906},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
doi = {10.1145/3570361.3614083},
booktitle = {Proceedings of the 29th Annual International Conference on Mobile Computing and Networking},
articleno = {109},
numpages = {3}
}
In this paper, we demonstrate PassiveLiFi, a battery-free system that works at the intersection of Light-Fidelity (LiFi) and Radio-Frequency (RF) backscatter technologies to enable long-range and ultra-low power wireless communications. We show how the PassiveLiFi tag can transmit real measured data through an interactive demo, and we display the received data in a customized graphical user interface. Our demo shows the suitability of PassiveLiFi for implementing real IoT applications, such as monitoring systems for smart agrifood facilities (i.e., greenhouses and vertical farms).
Mir, M. S., Majlesein, B., Guzman, B. G., Rufo, J., & Giustiniano, D. (2022). RGB LED Bulbs for Communication, Harvesting and Sensing. 2022 IEEE International Conference on Pervasive Computing and Communications (PerCom), 180–186.
@inproceedings{9762392,
author = {Mir, Muhammad Sarmad and Majlesein, Behnaz and Guzman, Borja Genoves and Rufo, Julio and Giustiniano, Domenico},
booktitle = {2022 IEEE International Conference on Pervasive Computing and Communications (PerCom)},
title = {RGB LED Bulbs for Communication, Harvesting and Sensing},
year = {2022},
volume = {},
number = {},
pages = {180-186},
keywords = {},
doi = {10.1109/PerCom53586.2022.9762392},
issn = {2474-249X},
month = mar
}
RGB LED bulbs have entered the market as a promising alternative to traditional phosphor coating LEDs to meet illumination standards. In this paper, we introduce and propose solutions to address the challenges of RGB LED lighting for the Internet of Things applications, performing communication, harvesting energy and sensing tasks. Through experiments, we demonstrate that we can use RGB LEDs for multiple tasks. We can achieve a bandwidth in the order of 50 kHz and distances of around 3.5 m using commercial RGB LED bulbs as transceivers, without using any dedicated photodetector. RGB LED links are composed of three main colours, and we show that red is the best colour both for communicating to another receiving RGB LED bulb, as well as for harvesting with a solar cell; green and blue can instead be exploited for standard-compliant lighting and/or sensing purposes. We evaluate the system in two proof of concepts and provide insights for operating RGB LEDs for multiple tasks.
Mir, M. S., Majlesein, B., Guzman, B. G., Rufo, J., & Giustiniano, D. (2021). LED-to-LED Based VLC Systems: Developments and Open Problems. Proceedings of the Workshop on Internet of Lights Co-Located with ACM MobiSys 2021, 1–6.
@inproceedings{10.1145/3469264.3469805,
author = {Mir, Muhammad Sarmad and Majlesein, Behnaz and Guzman, Borja Genoves and Rufo, Julio and Giustiniano, Domenico},
title = {LED-to-LED Based VLC Systems: Developments and Open Problems},
year = {2021},
isbn = {9781450386043},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
doi = {10.1145/3469264.3469805},
booktitle = {Proceedings of the Workshop on Internet of Lights co-located with ACM MobiSys 2021},
pages = {1–6},
numpages = {6},
keywords = {taxonomy, visible light communication, LED as receiver, opportunities, LED-to-LED},
location = {Virtual Event, Wisconsin},
series = {IoL '21}
}
Visible light communication (VLC) is an emerging short-range wireless communication technology using the unlicensed light spectrum. Light Emitting Diode (LED) is used as VLC transmitter, while photodiodes or image sensors are used as receiver, depending on the applications and hardware constraints. However, LEDs can be used not only as a transmitter, but also as a receiver in applications where cost is of primary concern. LED as a receiver is sensitive to a narrow band of wavelengths, it is robust to sunlight interference and widely available as compared to other light detectors. This paper surveys the potential and limitations of LED-to-LED communication. It also contributes to identifying the challenges and potential research directions in this rising area of interest.
Talavante, J., Genoves, B., & Giustiniano, D. (2021). Multi-Cell Deployment for Experimental Research in Visible Light Communication-Based Internet of Things. Proceedings of the Workshop on Internet of Lights Co-Located with ACM MobiSys 2021, 27–32.
@inproceedings{10.1145/3469264.3469802,
author = {Talavante, Javier and Genoves, Borja and Giustiniano, Domenico},
title = {Multi-Cell Deployment for Experimental Research in Visible Light Communication-Based Internet of Things},
year = {2021},
isbn = {9781450386043},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
doi = {10.1145/3469264.3469802},
booktitle = {Proceedings of the Workshop on Internet of Lights co-located with ACM MobiSys 2021},
pages = {27–32},
numpages = {6},
keywords = {IoT, prototyping, multi-cell setup, visible light communication, LiFi},
location = {Virtual Event, Wisconsin},
series = {IoL '21}
}
Visible Light Communication (VLC) provides both illumination and communication thanks to the usage of Light-Emitting Diodes (LEDs). In order to support the research in the field, the study of possible infrastructures to enable constant illumination and reliable communication becomes a necessity to pair up the evolution of both fields. Leveraging the fact that LEDs are getting more densely deployed to provide uniform illumination, in this work we present the design of a multi-cell deployment that uses several LEDs as VLC Access Points (APs) for Internet of Things (IoT) applications. We characterize the light emitted by the selected LED and show how this deployment complies with the illumination standards, as well as providing a reliable communication network. We present our design choices for controlling and communicating to the network of VLC APs, and show the required functionalities that must be fulfilled such as power monitoring, power management, and communication management.
Mir, M. S., Guzman, B. G., Varshney, A., & Giustiniano, D. (2021). PassiveLiFi: Rethinking LiFi for Low-Power and Long Range RF Backscatter. Proceedings of the 27th Annual International Conference on Mobile Computing and Networking, 697–709.
@inproceedings{10.1145/3447993.3483262,
author = {Mir, Muhammad Sarmad and Guzman, Borja Genoves and Varshney, Ambuj and Giustiniano, Domenico},
title = {PassiveLiFi: Rethinking LiFi for Low-Power and Long Range RF Backscatter},
year = {2021},
isbn = {9781450383424},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
doi = {10.1145/3447993.3483262},
booktitle = {Proceedings of the 27th Annual International Conference on Mobile Computing and Networking},
pages = {697–709},
numpages = {13},
location = {New Orleans, Louisiana},
series = {MobiCom '21}
}
Light bulbs have been recently explored to design Light Fidelity (LiFi) communication to battery-free tags, thus complementing Radiofrequency (RF) backscatter in the uplink. In this paper, we show that LiFi and RF backscatter are complementary and have unexplored interactions. We introduce PassiveLiFi, a battery-free system that uses LiFi to transmit RF backscatter at a meagre power budget. We address several challenges on the system design in the LiFi transmitter, the tag and the RF receiver. We design the first LiFi transmitter that implements a chirp spread spectrum (CSS) using the visible light spectrum. We use a small bank of solar cells for communication and harvesting and reconfigure them based on the amount of harvested energy and desired data rate. We further alleviate the low responsiveness of solar cells with a new low-power receiver design in the tag. Experimental results with an RF carrier of 17 dBm show that we can generate RF backscatter with a range of 80.3 meters/μW consumed in the tag, which is almost double with respect to prior work.
Galisteo, A., Marcocci, P., Zuniga, M., Mucchi, L., Guzmán, B. G., & Giustiniano, D. (2020). Filtering Visible Light Reflections with a Single-Pixel Photodetector. 2020 17th Annual IEEE International Conference on Sensing, Communication, and Networking (SECON), 1–9.
@inproceedings{9158414,
author = {Galisteo, Ander and Marcocci, Patrizio and Zuniga, Marco and Mucchi, Lorenzo and Guzmán, Borja Genovés and Giustiniano, Domenico},
booktitle = {2020 17th Annual IEEE International Conference on Sensing, Communication, and Networking (SECON)},
title = {Filtering Visible Light Reflections with a Single-Pixel Photodetector},
year = {2020},
volume = {},
number = {},
pages = {1-9},
keywords = {},
doi = {10.1109/SECON48991.2020.9158414},
issn = {2155-5494},
month = jun
}
Light-based positioning systems (LPS) are gaining significant attention as a means to provide localization with cm accuracy. Many of these systems estimate the object position based on the received light intensity, and work properly in ‘ideal’ environments such as large open spaces without obstructions around the light-emitting diode (LED) and the receiver, where reflections are negligible. In more dynamic environments, such as indoor spaces with moving people and city roads with moving vehicles, materials cause a wide variety of reflections. This causes variations in the received light intensity and, as a consequence, gross localization errors in LPS. We propose a new multipath detection technique for improving LPS that does not require the knowledge of the channel impulse response and then, it is suited to be implemented in low-cost positioning receivers that use a single-pixel photodetector. To develop our technique, we (i) analyze the statistical properties of non-line-of-sight (NLOS) components, (ii) develop an automated testbed to study the reflections of different types of surfaces and materials, and (iii) design an algorithm to remove the NLOS components affecting the positioning estimate. Our experimental evaluation shows that, in complex environments, our methodology can reduce the localization error using LEDs up to 93%.
Mir, M. S., Solanki, D., & Giustiniano, D. (2020). Poster: Integration between Home Automation and Visible Light Communications. Proceedings of the 2020 International Conference on Embedded Wireless Systems and Networks (EWSN), 170–171.
@inproceedings{10.5555/3400306.3400331,
author = {Mir, Muhammad Sarmad and Solanki, Deepak and Giustiniano, Domenico},
title = {Poster: Integration between Home Automation and Visible Light Communications},
year = {2020},
isbn = {9780994988645},
publisher = {Junction Publishing},
address = {USA},
booktitle = {Proceedings of the 2020 International Conference on Embedded Wireless Systems and Networks (EWSN)},
pages = {170–171},
numpages = {2},
location = {Lyon, France},
series = {EWSN '20}
}
In the near future, the Internet of Things (IoT) will take a predominant role in home automation and a reliable technology must satisfy the high demand on data traffic, energy consumption and reliability. This poster reveals a novel solution for home automation that relies on visible light communication.
Mir, M. S., Guzman, B. G., Galisteo, A., & Giustiniano, D. (2020). Non-Linearity of LEDs for VLC IoT Applications. Proceedings of the Workshop on Light Up the IoT Co-Located with ACM MobiCom 2020, 6–11.
@inproceedings{10.1145/3412449.3412552,
author = {Mir, Muhammad Sarmad and Guzman, Borja Genoves and Galisteo, Ander and Giustiniano, Domenico},
title = {Non-Linearity of LEDs for VLC IoT Applications},
year = {2020},
isbn = {9781450380997},
publisher = {Association for Computing Machinery},
address = {New York, NY, USA},
doi = {10.1145/3412449.3412552},
booktitle = {Proceedings of the Workshop on Light Up the IoT co-located with ACM MobiCom 2020},
pages = {6–11},
numpages = {6},
keywords = {internet-of-things, visible light communication, LED non-linearity, OpenVLC},
location = {London, United Kingdom},
series = {LIOT '20}
}
Visible light communication (VLC) is a promising technology to satisfy the increasing demand of wireless communication services. The generalized idea of modulating the signal within the light-emitting diode (LED) linear region is considered the de-facto approach for high-speed communication. This paper shows that this is not the most appropriate choice for the Internet of Things (IoT) applications, where the communication range is of greater importance once a sufficient communication rate is reached. In order to improve the communication range, we propose to exploit the full non-linear region of an LED transceiver while maintaining constant illumination. We show that working in the full LED region can provide received electrical power gains in the mobile IoT tag of around 15 dB. We achieve this without affecting the communication rate for IoT applications, and at the penalty of about 10% increase in the total energy consumption of LEDs. We further demonstrate that exploiting the non-linear region of LEDs is beneficial for mobile tags that employ a solar cell for receiving data at high data rates.
Guzmán, B. G., Dowhuszko, A. A., Gil Jiménez, V. P., & Pérez-Neira, A. I. (2019). Cooperative transmission scheme to address random orientation and blockage events in VLC systems. 2019 16th International Symposium on Wireless Communication Systems (ISWCS), 351–355.
@inproceedings{8877133,
author = {Guzmán, Borja Genovés and Dowhuszko, Alexis A. and Gil Jiménez, Víctor P. and Pérez-Neira, Ana I.},
booktitle = {2019 16th International Symposium on Wireless Communication Systems (ISWCS)},
title = {Cooperative transmission scheme to address random orientation and blockage events in VLC systems},
year = {2019},
volume = {},
number = {},
pages = {351-355},
keywords = {},
doi = {10.1109/ISWCS.2019.8877133},
issn = {2154-0225},
month = aug
}
Visible light communication (VLC) is a promising communication technology that paves the way to the Internet of Things. The forthcoming Industry 4.0 requires reliable high-speed communication links, which can be easily fulfilled with the massive adoption of the VLC technology. However, in VLC indoor communication environments, line-of-sight link blockages and strong misalignment losses between the light-emitting diode (LED) transmitters and the photodiode (PD) receivers are usual problems that must be tackled. This paper proposes a coordinated multi-point (CoMP) transmission technique to deal with both issues, and carries out a detailed evaluation of the VLC system performance as function of the PD receiver orientation and the density of obstacles in different scenarios. The proposed cooperative transmission scheme demonstrates an improvement in the average cell data rate and outage probability performance and, as a consequence, justifies the use of CoMP techniques to provide reliable VLC services in ultra-dense small cell scenarios indoors.
Estrada-Jiménez, J. C., Guzmán, B. G., García, M. J. F.-G., & Jiménez, V. P. G. (2018). Comparativa de técnicas de estimación de canal para VLC en interiores. XXXIII Simposium Nacional De La Unión Científica Internacional De Radio (URSI).
@inproceedings{EstimateVLCChannel,
author = {Estrada-Jiménez, J. C. and Guzmán, B. Genovés and García, M. J. Fernández-Getino and Jiménez, V. P. Gil},
booktitle = {XXXIII Simposium Nacional de la Unión Científica Internacional de Radio (URSI)},
title = {Comparativa de técnicas de estimación de canal para VLC en interiores},
year = {2018}
}
Leal, R. P., Garzás, J. J. E., Guzmán, B. G., Jiménez, V. P. G., & Armada, A. G. (2018). Tecnología de comunicaciones móviles al alcance de todos: la experiencia del MOOC. XXXIII Simposium Nacional De La Unión Científica Internacional De Radio (URSI).
@inproceedings{MOOC,
author = {Leal, R. Pérez and Garzás, J. J. Escudero and Guzmán, B. Genovés and Jiménez, V. P. Gil and Armada, A. García},
booktitle = {XXXIII Simposium Nacional de la Unión Científica Internacional de Radio (URSI)},
title = {Tecnología de comunicaciones móviles al alcance de todos: la experiencia del MOOC},
year = {2018}
}
Chen-Hu, K., Guzmán, B. G., Jiménez, V. P. G., & Armada, A. G. (2018). Layered ACO-CP-OFDM with insufficient Cyclic Prefix for Visible Light Communications. XXXIII Simposium Nacional De La Unión Científica Internacional De Radio (URSI).
@inproceedings{LayeredACO,
author = {Chen-Hu, K. and Guzmán, B. Genovés and Jiménez, V. P. Gil and Armada, A. García},
booktitle = {XXXIII Simposium Nacional de la Unión Científica Internacional de Radio (URSI)},
title = {Layered ACO-CP-OFDM with insufficient Cyclic Prefix for Visible Light Communications},
year = {2018}
}
Guzman, B. G., Cortés, T. M., López, Á. R., & Armada, A. G. (2017). Design of a communication, vision and sensory system for a rescuer robot in coal mine areas. 2017 International Conference on Wireless Networks and Mobile Communications (WINCOM), 1–5.
@inproceedings{8238150,
author = {Guzman, Borja Genovés and Cortés, Tomás Martínez and López, Ángel Rodríguez and Armada, Ana García},
booktitle = {2017 International Conference on Wireless Networks and Mobile Communications (WINCOM)},
title = {Design of a communication, vision and sensory system for a rescuer robot in coal mine areas},
year = {2017},
volume = {},
number = {},
pages = {1-5},
keywords = {},
doi = {10.1109/WINCOM.2017.8238150},
issn = {},
month = nov,
location = {Rabat, Morocco}
}
Rescue tasks in coal mines are fundamental but often suppose the loss of rescuers lives, as currently they are carried out only by humans. TeleRescuer project expects to make this activity safer by developing a robot to be driven by rescuers from a safe area. It offers virtual teleportation providing to the operator an environment where he can interact with the reality perceived by the robot. In this paper, the design of the communication, vision and sensory systems are presented, giving an overview of all the elements that are included in the robot. The adaptation of these electronics to the hazardous environment is also explained. A prototype of an ad-hoc wireless network and results in terms of the transmission characteristics are shown.
Dowhuszko, A. A., Gil Jiménez, V. P., Gumán, B. G., & Pérez-Neira, A. I. (2017). Distance-aware coordinated multi-point transmission for terahertz band communication. 2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), 1–5.
@inproceedings{8227803,
author = {Dowhuszko, Alexis A. and Gil Jiménez, Víctor P. and Gumán, Borja Genovés and Pérez-Neira, Ana I.},
booktitle = {2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)},
title = {Distance-aware coordinated multi-point transmission for terahertz band communication},
year = {2017},
volume = {},
number = {},
pages = {1-5},
keywords = {},
doi = {10.1109/SPAWC.2017.8227803},
issn = {1948-3252},
month = jul,
location = {Sapporo, Japan}
}
Terahertz (THz) band communication has abundant spectral resources to accommodate multiple broadband carriers. However, the strong path loss attenuation and the limited transmission power affect the maximum number of carriers that can be activated. A simple way to address this limitation consists in transmitting the same message from multiple transmission points, using Joint-Transmission (JT) Coordinated Multi-Point (CoMP). However, the distance-frequency-dependent molecular absorption that THz channels experience makes the implementation of JT-CoMP challenging. In this paper, we propose a decentralized scheme that takes into account the effect of distance to select the per-carrier transmit beamforming weights and powers. For this purpose, low-rate feedback information is reported from the receiver to the transmission points, such that decisions performed locally take into account the ones made in the coordinated set. Notable sum data rate gains are observed when compared to the baseline schemes, where transmission power is equally divided among carriers or independently allocated using waterfilling. As expected, the accuracy of the reported channel phase information, the number active transmission points, and the distance-dependent frequency selectivity of the THz channel affect the sum data rate that multi-carrier JT-CoMP can provide.
Estrada Jiménez, J. C., Genovés Guzmán, B., Fernández-Getino García, M. J., & Gil Jiménez, V. P. (2017). Superimposed training-based channel estimation for Visible Light Communications. 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), 240–245.
@inproceedings{7986293,
author = {Estrada Jiménez, Juan Carlos and Genovés Guzmán, Borja and Fernández-Getino García, M. Julia and Gil Jiménez, Víctor P.},
booktitle = {2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC)},
title = {Superimposed training-based channel estimation for Visible Light Communications},
year = {2017},
volume = {},
number = {},
pages = {240-245},
keywords = {},
doi = {10.1109/IWCMC.2017.7986293},
issn = {2376-6506},
month = jun
}
Visible Light Communications (VLC) is considered one of the most promising technologies to guarantee the future demand of user wireless data rate. Since a DC value is needed for illumination, Direct Current-biased Optical Orthogonal Frequency Division Multiplexing (DCO-OFDM) is adopted as modulation technique in these environments. Channel estimation in VLC is quite different from the conventional radiofrequency (RF) counterparts because the indoor optical wireless channel model significantly differs from the traditional RF one. Previous proposals rely on dedicated pilot symbols to perform channel estimation what leads to a loss in efficiency. In this paper, we propose a novel approach of Superimposed Training (ST) for channel estimation in VLC scenarios.
Novak, P., Babjak, J., Kot, T., Bobovský, Z., Olivka, P., Moczulski, W., Timofiejczuk, A., Adamczyk, M., Guzman, B. G., Armada, A. G., & Rodriguez, A. (2017, February). Telerescuer - reconnaissance mobile robot for underground coal mines. Coal Operators’ Conference 2017.
@inproceedings{Telerescuer,
author = {Novak, P. and Babjak, J. and Kot, T. and Bobovský, Z. and Olivka, P. and Moczulski, W. and Timofiejczuk, A. and Adamczyk, M. and Guzman, B. Genoves and Armada, A. Garcia and Rodriguez, A.},
booktitle = {Coal Operators’ Conference 2017},
title = {Telerescuer - reconnaissance mobile robot for underground coal mines},
year = {2017},
keywords = {},
doi = {https://ro.uow.edu.au/coal/672/},
month = feb,
location = {Wollongong, Australia}
}
Guzmán, B. G., Adamczyk, M., Timofiejczuk, A., & Armada, A. G. (2016, September). Design of a Sensory and Vision System for a Rescuer Robot in Coal Mine Areas. 6th International Congress on Technical Diagnostic (ICDT’2016).
@inproceedings{Telerescues,
author = {Guzmán, B. Genovés and Adamczyk, M. and Timofiejczuk, A. and Armada, A. Garcia},
booktitle = {6th International Congress on Technical Diagnostic (ICDT’2016)},
title = {Design of a Sensory and Vision System for a Rescuer Robot in Coal Mine Areas},
year = {2016},
keywords = {},
doi = {https://link.springer.com/chapter/10.1007/978-3-319-62042-8_45},
month = sep,
location = {Gliwice, Poland}
}
Guzmán, B. G., & Jiménez, V. P. G. (2016). The Near Future of Visible Light Communications (VLC). IEEE Communications Society Summer School.
@inproceedings{comsocSummerSchool,
author = {Guzmán, B. G. and Jiménez, V. P. Gil},
booktitle = {IEEE Communications Society Summer School},
title = {The Near Future of Visible Light Communications (VLC)},
year = {2016},
location = {Trento, Italy}
}
Guzmán, B. G., & Jiménez, V. P. G. (2014). Señales DCO-OFDM eficientes para VLC utilizando Redes Neuronales adaptativas Difusas (ANFIS). XXIX Simposium Nacional De La Unión Científica Internacional De Radio (URSI).
@inproceedings{ursi,
author = {Guzmán, B. G. and Jiménez, V. P. Gil},
booktitle = {XXIX Simposium Nacional de la Unión Científica Internacional de Radio (URSI)},
title = {Señales DCO-OFDM eficientes para VLC utilizando Redes Neuronales adaptativas Difusas (ANFIS)},
year = {2014},
location = {Valencia, Spain}
}
Book chapters
Guzmán, B. G., Jiménez, V. P. G., & Pérez, R. P. (2019). Peak-to-Average Power Ratio Reduction Techniques. In Wiley 5G Ref (pp. 1–32). John Wiley & Sons, Ltd.
@inbook{PAPRChapter,
author = {Guzmán, Borja Genovés and Jiménez, Víctor P. Gil and Pérez, Roberto Pérez},
publisher = {John Wiley & Sons, Ltd},
isbn = {9781119471509},
title = {Peak-to-Average Power Ratio Reduction Techniques},
booktitle = {Wiley 5G Ref},
chapter = {},
pages = {1-32},
doi = {https://doi.org/10.1002/9781119471509.w5GRef011},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781119471509.w5GRef011},
year = {2019},
keywords = {5G, high-power amplifiers, multicarrier modulations, nonlinear distortions, PAPR, power envelope}
}
Multicarrier transmission schemes produce time-domain (TD) signals with large envelope fluctuations. These signals suffer from nonlinear distortions when passing through a high-power amplifier (HPA) because of its nonlinear transfer function. Several metrics are used to quantify the envelope fluctuations: peak-to-average power ratio (PAPR), crest factor (CF), and cubic metric (CM). Multiple techniques and algorithms have been proposed for reducing such metrics in the literature. This article reviews all the possible PAPR reduction techniques and emphasizes the importance of their application in multicarrier schemes. Besides, new variants adapted to multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) are also presented, which take on importance in 5G systems. Finally, a comparison among these techniques is presented in terms of the key aspects considered when designing a 5G system: power increase, implementation complexity, bit error rate (BER) degradation, and required side information. It is shown that the selection of the PAPR reduction technique depends on the application, the system requirements, and the scenario.
PhD Thesis
Genoves Guzman, B. (2019). Performance enhancement techniques for visible light communication systems [PhD thesis]. University Carlos III of Madrid.
@phdthesis{BorjaThesis,
title = {Performance enhancement techniques for visible light communication systems},
author = {Genoves Guzman, Borja},
year = {2019},
school = {University Carlos III of Madrid},
doi = http://hdl.handle.net/10016/29495,
file = {tesis_borja_genoves_guzman_2019.pdf}
}
Invited presentations
Borja Genoves Guzman and Maïté Brandt-Pearce. (2023-April). Visible Light Communications for the IoT. In University of Virginia for the Wireless IoT Course (CS/ECE4501).
@misc{Presentation1,
author = {{Borja Genoves Guzman and Maïté Brandt-Pearce}},
title = {Visible Light Communications for the IoT},
booktitle = {University of Virginia for the Wireless IoT Course (CS/ECE4501)},
year = {2023-April}
}
Borja Genoves Guzman. (2021-October). LiFi for Low-Energy IoT Systems. In Computer Networking Weekly Research Seminar Series at the Department of Computer Science and Engineering, University of California, Santa Cruz (UCSC).
@misc{Presentation2,
author = {{Borja Genoves Guzman}},
title = {LiFi for Low-Energy IoT Systems},
booktitle = {Computer Networking Weekly Research Seminar Series at the Department of Computer Science and Engineering, University of California, Santa Cruz (UCSC)},
year = {2021-October}
}
Borja Genoves Guzman. (2020-February). Hardware layer: Transmitters, Receivers, and Optical Materials for VLC. In “A tutorial on Visible Light Communication: An Academic and Industrial Perspective” at the International Conference on Embedded Wireless Systems and Networks (EWSN 2020).
@misc{Presentation3,
author = {{Borja Genoves Guzman}},
title = {Hardware layer: Transmitters, Receivers, and Optical Materials for VLC},
booktitle = {“A tutorial on Visible Light Communication: An Academic and Industrial Perspective” at the International Conference on Embedded Wireless Systems and Networks (EWSN 2020)},
year = {2020-February}
}