Papers by Heikki Karvonen
Cognitive radios are considered critical for better spectrum use in 5G networks. Spectrum sensing... more Cognitive radios are considered critical for better spectrum use in 5G networks. Spectrum sensing is a technology that allows channel status to be determined on a decentralized basis. Collaborative spectrum sensing improves detection by collecting more data from different users in different places, increasing the amount of information available to making decisions. This paper presents a Markov chain-based technique that improves spectrum detection and decreases the number of sensing notifications. Thus, the technique improves the result of classic fusion algorithms for co-operative sensing in the case of wellbehaved access. There was a reduction of up to∼ 99.67% in the false alarm rate and up to ∼ 98% of the associated control traffic, preserving the false negative rate below the tolerable limit of 10%, mitigating the interference to a channel user. Resumo. Os rádios cognitivos são considerados fundamentais para melhorar o uso do espectro em redes 5G. O sensoriamento de espectro é u...
Inthis paper, energy efficiency offorward errorcorrec- tion(FEC)coding inultra wideband (UWB)wire... more Inthis paper, energy efficiency offorward errorcorrec- tion(FEC)coding inultra wideband (UWB)wireless sensor net- works(WSNs)isstudied taking intoaccount thecharacteristics of thephysical (PHY)andmediumaccess control (MAC)layers. The underlying goalhasbeentodevelop across-layer framework that allows thedesign ofenergyefficient FEC coding inUWB WSNs. Thisstudyiscarried outusinganalytical derivations andsimula- tions. A cross-layer approach, suchastheonedescribed here, pro- vides adeeper understanding ofthevarious factors thataffect the energy consumption inWSNs,andhowFECcoding canimprove it. Results clearly showthatcoding improves theenergy efficiency in UWB transceivers. Byusing theframework introduced here, UWB networkdesigners cananalyze thenetworkenergyefficiency al- readyinthedesign phase.
2006 IEEE International Conference on Ultra-Wideband, 2006
In this paper, energy efficiency of forward error correction (FEC) coding in ultra wideband (UWB)... more In this paper, energy efficiency of forward error correction (FEC) coding in ultra wideband (UWB) wireless sensor networks (WSNs) is studied taking into account the characteristics of the physical (PHY) and medium access control (MAC) layers. The underlying goal has been to develop a cross-layer framework that allows the design of energy efficient FEC coding in UWB WSNs. This study
2019 13th International Symposium on Medical Information and Communication Technology (ISMICT), 2019
ArXiv, 2020
In many places all over the world rural and remote areas lack proper connectivity that has led to... more In many places all over the world rural and remote areas lack proper connectivity that has led to increasing digital divide. These areas might have low population density, low incomes, etc., making them less attractive places to invest and operate connectivity networks. 6G could be the first mobile radio generation truly aiming to close the digital divide. However, in order to do so, special requirements and challenges have to be considered since the beginning of the design process. The aim of this white paper is to discuss requirements and challenges and point out related, identified research topics that have to be solved in 6G. This white paper first provides a generic discussion, shows some facts and discusses targets set in international bodies related to rural and remote connectivity and digital divide. Then the paper digs into technical details, i.e., into a solutions space. Each technical section ends with a discussion and then highlights identified 6G challenges and research...
Wireless Medical Systems and Algorithms, 2017
2019 16th International Symposium on Wireless Communication Systems (ISWCS), 2019
The 5G mobile networks will increase the amount of available spectrum by using new licensed and u... more The 5G mobile networks will increase the amount of available spectrum by using new licensed and unlicensed bands. However, most of the newly allocated bandwidth is restricted to higher frequencies, that provides smaller coverage. Lower frequencies, that provide higher ranges, are mostly occupied by either radio or television channels. With the move to digital television, some analog TV channels are available in specific regions, opening the possibility of frequency reuse by third parties. Geolocation databases and collaborative sensing techniques are used to locate and use the available TV Whitespaces (TVWS) for mobile transmission. This paper presents the proposal of a cognitive cycle in the ns-3 simulator (LENA/LTE), which includes collaborative sensing and a cognitive radio resource scheduler. The simulations were done considering a rural area and the results show that the implementation may be useful for further research in developing new solutions for the 5G Cognitive MAC Layer.
2020 IFIP Networking Conference (Networking), 2020
Cognitive radios and spectrum sensing are considered fundamental for spectrum optimization in 5G ... more Cognitive radios and spectrum sensing are considered fundamental for spectrum optimization in 5G networks. Collaborative spectrum sensing improves detection by collecting data from different nodes and increasing the amount of information available for accurate channel state detection. However, malicious nodes can report wrong information, disturbing the collaborative sensing results and network operation. This paper presents two techniques: (1) a Markov chain-based technique that improves spectrum sensing accuracy while reducing the reporting control traffic; (2) a harmonic mean-based technique that discards less relevant sensing reports, mitigating Byzantine attacks. The two techniques were evaluated in a simulation scenarios based on rural areas. The results show that the proposed techniques increase the accuracy of a classic hard-combining fusion technique, reducing false positives and reporting overhead while improving network resilience to malicious nodes.
2020 2nd 6G Wireless Summit (6G SUMMIT), 2020
The current trend of delivering goods is to use lockers located close to the customers. The locke... more The current trend of delivering goods is to use lockers located close to the customers. The locker needs to communicate with a delivery system, which is most convenient to achieve with wireless technologies. There are mechanical, industrial design and reliability advantages to place a radio unit inside of the locker. However, it is challenging from a radio communication perspective, especially with conducting door material like metal. In this work, RF radiation performance from inside of the metallic locker with two different door materials was studied. The studied RF frequencies cover operational frequencies of LTE NBIoT, Sigfox, LoRa, Wifi, and 5G NR at 3.5 GHz. The simulations and measurements show that the radiation pattern of the metal door locker resemble radiation pattern of array. The main radiation direction with metal doors can be backside of the locker, while with a wood laminate the primary radiation direction is toward front side of the locker.
This paper studies the effect of coding on the energy consumption of multihop communications in W... more This paper studies the effect of coding on the energy consumption of multihop communications in Wireless Sensor Networks. In these networks, there are strict energy consumption constraints because the battery capacity at each node is limited and the goal is to maximize the lifetime of the network. An analytical radio model for energy consumption is used to study the effect of different codes on energy consumption. Tradeoffs between coding overhead and energy consumption per information bit for different channel bit error probabilities and different numbers of hops are computed. For a multihop scenario the numerical results show the tradeoffs between the codes’ energy efficiency, the channel conditions, and the number of hops.
The energy efficiency is an important issue for a vast range of the Internet of Things (IoT) appl... more The energy efficiency is an important issue for a vast range of the Internet of Things (IoT) applications. However, especially critical is the energy efficiency in the context of wearable and body-area network devices. At the very same time, due to their nature, these use cases often impose stringent latency and reliability requirements. In this study, we provide an insight into the feasibility and the performance of the Bluetooth Low Energy (BLE) 5.0 compatible sensor devices enriched with a wake-up radio (WUR). Introduction of a low-consuming WUR radio equips a sensing device with a mechanism to know when its data are desired, and helps to avoid the unnecessary data transmissions thus saving energy. To investigate the utility of this approach and the associated with it trade-offs, we start by instrumenting and measuring a real-life prototype of a WUR-equipped BLE device. Based on the results of the real-life measurements, we first develop the analytical models, and then analyze ho...
Connectivity in remote and rural areas is a challenge which is not sufficiently tackled by the on... more Connectivity in remote and rural areas is a challenge which is not sufficiently tackled by the on-going development of 5G networks. Alternative operator models that promote the establishment of locally deployed networks to serve the under-served are important to complement the mobile network operator (MNO) driven connectivity market to serve the underserved. This paper describes the connectivity challenges that remote and rural areas face and proposes a generic spectrum sharing model that allows local deployment of 5G networks with new local operator models. The proposed approach consists of different levels of spectrum access rights that are realized with on combined use of a geolocation database to protect the incumbent spectrum users and spectrum sensing to facilitate sharing between the local 5G networks. The propose approach allows different stakeholders to become local rural and remote area operators by gaining access to the spectrum locally through shared access to the spectrum.
2017 11th International Symposium on Medical Information and Communication Technology (ISMICT)
13th EAI International Conference on Body Area Networks
In this chapter, the focus is on analytical and experimental performance evaluation of the Blueto... more In this chapter, the focus is on analytical and experimental performance evaluation of the Bluetooth Low Energy (BLE) technology. Studies have been conducted in indoor case relevant to healthcare and medical scenarios. Performance of the recently developed BLE 5 coded technique is compared to BLE 4 that is currently the most popular wireless technology in commercial healthcare and medical solutions. The improved version of BLE may continue the popularity of BLE usage in those application scenarios, and in addition it may enable novel Internet of Things (IoT) solutions. The main objective of this work was to explore the packet error rate (PER) of BLE communication under ZigBee interference, since it is envisaged, that coexistence problems may arise with the further growth of number of the different IoT devices deployed. In this chapter, we first develop an analytical model to characterize the PER of BLE link with varying distance to interfering nodes. Then we conduct a series of practical measurements using the Nordic Semiconductor nRF52840 chipset, which supports the new BLE 5 coded features. Our results show that ZigBee interference is very harmful for BLE communication when operating at the same frequency band, i.e., assuming worst-case scenario. The proposed model can be used to evaluate PER of BLE in various interference scenarios to get insight of communication reliability which is very important specifically for healthcare and medical applications.
2019 16th International Symposium on Wireless Communication Systems (ISWCS)
Connectivity in low-density rural and remote areas where distances are long is a big challenge be... more Connectivity in low-density rural and remote areas where distances are long is a big challenge because of high deployment costs and challenging radio channels with long delay profiles. Spectrum sharing can make spectrum available for 5G local network deployments to serve rural and remote areas. Spectrum sensing can be used to complement the traditional database approach in order to enable efficient and dynamic use of the radio spectrum. In rural and remote areas, long range coverage is required in order to enable flexible and cost-effective solutions. This calls for efficient and low-complex sensing methods who are able to operate in those challenging environments. In this paper we study spectrum sensing method called the window-based (WIBA) energy detector in a challenging rural area channel model for 5G networks. The results are compared to that of the localization algorithm based on double-thresholding (LAD) energy detector. Simulations using a rural area channel model with long delay profile indicated that the WIBA method is able to operate in a rural area channel, and it clearly outperforms the LAD method in terms of detection distance. The detection difference was even 15-fold for the WIBA method, depending on the transmit power and the signal bandwidth.
EAI Endorsed Transactions on Wireless Spectrum, Apr 7, 2020
2017 IEEE 17th International Conference on Ubiquitous Wireless Broadband (ICUWB), Sep 1, 2017
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Papers by Heikki Karvonen