Divergent modulation schemes have been proposed for the Internet of Things (IoT). Low Power Wide Area
Networks (LPWAN) technologies are gaining unprecedented acceptance in IoT application of sensor
networks. Chirp Spread Spectrum (CSS) is a prominent modulation technique proposed for LPWAN. Chirps
can traverse long distance and are resilient to noise and Doppler effects. Noise resilience along with
transmission range and low power requirement makes CSS a preferred modulation scheme for sensor
networks. LoRaWANTM, with its physical (PHY) layer using CSS, has emerged as the widely accepted
LPWAN solution. By using CSS modulation with orthogonal spreading factors (SF), LoRa offers wide
coverage to LPWAN applications while supporting a high volume of devices. However, scalability
performance of CSS has not been inadequately modeled. As with the suitability of the modulation scheme,
there are concerns on how chirps interact with the surrounding as the number of deployments bursts out
into higher volumes. We evaluate CSS at ISM band 868 MHz for spreading factor 7 to 12 at bandwidth 125
kHz for performance and scalability. Simultaneous transmissions were simulated with repeated iterations
and conclusions are arrived on collisions rate, packet error rate, and bit error. Suitability of using CSS for
sensor networks for future deployments is commended.
Cognitive Radio definition and benefits Mustafa Sadiq
cognitive radio definition and its relationship to the software defined radio is explained in this presentation. The spectrum sense is also explained here as well
Although many techniques exist to transfer data from the widely distributed sensors that make up the Internet of Things IoT e.g., using 3G 4G networks or cables , these methods are associated with prohibitively high costs, making them impractical for real life applications. LoRa Long Range modulation together with LoRaWAN LoRa Wide Area Networks communication protocol can represent a suitable candidate ensuring a high level of performance in wireless technologies. The objective is to contribute toward the realization of LoRa as a viable communication technology for applications that needs long range links and deployed in a distributed manner. The LoRaWAN networks are the evolution of wireless sensor networks directed to the IoT concept, which entails sensor connectivity to the Internet. LoRa technology is summarized by reviewing some aspects regarding the architecture, security and application of the technology. Ms. Helina Tandel | Ms. Anjali Gharat | Mr. Ketan Bagade "LoRa Technology - DNA of IoT" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd28102.pdf Paper URL: https://www.ijtsrd.com/engineering/computer-engineering/28102/lora-technology---dna-of-iot/ms-helina-tandel
IoT Needs Good Neighbours - Cognitive Radio Turns Enemies into FriendsAMIHO Technology
With the internet of things the use of connected devices is predicted to be in many tens of billions. In this presentation, Steve Clarke discusses the use of various wireless technologies and techniques such as cognitive radio to allow these devices to co-exist in harmony with their (many) neighbours.
Steve Clarke, Technical Director of AMIHO, presented this paper at the prestigious Embedded World conference,Feb 2016.
Wireless Personal Area Networks (WPAN): Lowrate amd High RateDon Norwood
This document provides an overview of wireless personal area networks (WPANs) and discusses two specific WPAN standards, 802.15.3 (WPAN-LR) and 802.15.13a (WPAN-HR). It describes the components and design considerations of wireless sensor networks, including their applications, network models, protocol stacks involving different layers, and power, mobility and task management planes. Diagrams are included illustrating a WPAN standard summary, wireless sensor network model, sensor node components, and the sensor network protocol stack.
Wireless Personal Area Networks – Bluetooth, UWB and Sensor Networks Manas Rai
This document provides an overview of wireless personal area networks (WPANs), with a focus on Bluetooth technology. Some key points:
- WPANs like Bluetooth operate over short ranges (around 10 meters) and support connections between devices in close proximity, using the ad hoc network model.
- The IEEE 802.15 standards group develops specifications for WPANs, adopting parts of the Bluetooth standard. It focuses on high and low data rate networks.
- Bluetooth is a widely used WPAN technology that allows devices to connect quickly within 10 meters at up to 1 Mbps without cables. It operates in the unlicensed 2.4GHz band.
- Emerging technologies like ultra-wide
CR technology is based on the fact that the licensed systems (also named primary systems PS) are not always using their spectrum bands; CR brings new radio types—cognitive radios—that should firstly, identify the existing spectrum holes, and secondly, utilize them according to an access
The document discusses cognitive radio networks and dynamic spectrum allocation. It proposes a cognitive sensor network testbed approach using cross-layer analysis. The key functions of cognitive radio devices are sensing to detect spectrum availability, decision making on transmission parameters, spectrum sharing through coordination, and mobility to switch frequencies. The proposal involves a cross-layer protocol stack with interfaces for sensing, decision making, and coordinating media access across layers. Challenges in implementing this approach on wireless sensor networks include time response, bandwidth limits, and energy consumption.
Personal area networks (PANs) allow communication between devices within close proximity of an individual. There are two main types of PANs - wired and wireless. Wireless PANs (WPANs) use technologies like infrared, Bluetooth, and HomeRF to connect devices within 10 meters. Common WPAN devices include PDAs, phones, and laptops. WPANs offer advantages like easy setup and portability but have limitations such as low data rates and limited range compared to wireless local area networks. WPANs can be used in education for sharing files between devices and printing wirelessly. The future of WPANs involves using human body signals to transmit data between devices.
Cognitive Radio definition and benefits Mustafa Sadiq
cognitive radio definition and its relationship to the software defined radio is explained in this presentation. The spectrum sense is also explained here as well
Although many techniques exist to transfer data from the widely distributed sensors that make up the Internet of Things IoT e.g., using 3G 4G networks or cables , these methods are associated with prohibitively high costs, making them impractical for real life applications. LoRa Long Range modulation together with LoRaWAN LoRa Wide Area Networks communication protocol can represent a suitable candidate ensuring a high level of performance in wireless technologies. The objective is to contribute toward the realization of LoRa as a viable communication technology for applications that needs long range links and deployed in a distributed manner. The LoRaWAN networks are the evolution of wireless sensor networks directed to the IoT concept, which entails sensor connectivity to the Internet. LoRa technology is summarized by reviewing some aspects regarding the architecture, security and application of the technology. Ms. Helina Tandel | Ms. Anjali Gharat | Mr. Ketan Bagade "LoRa Technology - DNA of IoT" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd28102.pdf Paper URL: https://www.ijtsrd.com/engineering/computer-engineering/28102/lora-technology---dna-of-iot/ms-helina-tandel
IoT Needs Good Neighbours - Cognitive Radio Turns Enemies into FriendsAMIHO Technology
With the internet of things the use of connected devices is predicted to be in many tens of billions. In this presentation, Steve Clarke discusses the use of various wireless technologies and techniques such as cognitive radio to allow these devices to co-exist in harmony with their (many) neighbours.
Steve Clarke, Technical Director of AMIHO, presented this paper at the prestigious Embedded World conference,Feb 2016.
Wireless Personal Area Networks (WPAN): Lowrate amd High RateDon Norwood
This document provides an overview of wireless personal area networks (WPANs) and discusses two specific WPAN standards, 802.15.3 (WPAN-LR) and 802.15.13a (WPAN-HR). It describes the components and design considerations of wireless sensor networks, including their applications, network models, protocol stacks involving different layers, and power, mobility and task management planes. Diagrams are included illustrating a WPAN standard summary, wireless sensor network model, sensor node components, and the sensor network protocol stack.
Wireless Personal Area Networks – Bluetooth, UWB and Sensor Networks Manas Rai
This document provides an overview of wireless personal area networks (WPANs), with a focus on Bluetooth technology. Some key points:
- WPANs like Bluetooth operate over short ranges (around 10 meters) and support connections between devices in close proximity, using the ad hoc network model.
- The IEEE 802.15 standards group develops specifications for WPANs, adopting parts of the Bluetooth standard. It focuses on high and low data rate networks.
- Bluetooth is a widely used WPAN technology that allows devices to connect quickly within 10 meters at up to 1 Mbps without cables. It operates in the unlicensed 2.4GHz band.
- Emerging technologies like ultra-wide
CR technology is based on the fact that the licensed systems (also named primary systems PS) are not always using their spectrum bands; CR brings new radio types—cognitive radios—that should firstly, identify the existing spectrum holes, and secondly, utilize them according to an access
The document discusses cognitive radio networks and dynamic spectrum allocation. It proposes a cognitive sensor network testbed approach using cross-layer analysis. The key functions of cognitive radio devices are sensing to detect spectrum availability, decision making on transmission parameters, spectrum sharing through coordination, and mobility to switch frequencies. The proposal involves a cross-layer protocol stack with interfaces for sensing, decision making, and coordinating media access across layers. Challenges in implementing this approach on wireless sensor networks include time response, bandwidth limits, and energy consumption.
Personal area networks (PANs) allow communication between devices within close proximity of an individual. There are two main types of PANs - wired and wireless. Wireless PANs (WPANs) use technologies like infrared, Bluetooth, and HomeRF to connect devices within 10 meters. Common WPAN devices include PDAs, phones, and laptops. WPANs offer advantages like easy setup and portability but have limitations such as low data rates and limited range compared to wireless local area networks. WPANs can be used in education for sharing files between devices and printing wirelessly. The future of WPANs involves using human body signals to transmit data between devices.
An overview of cognitive radio, comparison of cognitive radio vs. conventional radio, real-world applications for cognitive radio networks, how cognitive radios improve spectrum efficiency and address the wireless spectrum shortage.
The document provides an introduction to wireless sensor networks, including key terms and concepts. It discusses motes, which are low-power devices that integrate sensing, processing and radios. The document also covers operating systems like TinyOS that help program sensor networks, as well as advances in technology like MEMS, VLSI and wireless standards that enabled the development of sensor networks. Finally, it previews topics to be covered in the next class, including the differences between telemetry systems and sensor networks.
Dynamic frequency allocation in femtocells-based systems: algorithms and perf...Remo Pomposini
This document summarizes the PhD candidate Remo Pomposini's research on dynamic frequency allocation algorithms for femtocell-based systems. It discusses the problem of interference between densely deployed femtocells and proposes using cognitive radio techniques and dynamic frequency selection algorithms to intelligently allocate frequencies. It analyzes the performance of greedy and operator-oriented algorithms through simulations in various network topologies and deployment scenarios. The results show that the greedy algorithm comes closest to optimal frequency assignment and significantly increases the number of active femtocells compared to random assignment.
Cognitive radios are smart radios that can sense their environment and adjust their transmission parameters accordingly. They were first proposed in 1999 to more efficiently utilize limited radio spectrum. Cognitive radios operate in a cycle of spectrum sensing, decision, sharing, and mobility. They can access licensed spectrum as secondary users as long as they do not interfere with primary users. This allows for increased spectrum utilization. Cognitive radios have characteristics of cognitive capability, reconfigurability, and self-organization. They enable applications such as cognitive mesh networks and public safety networks through techniques like dynamic spectrum management.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document discusses cognitive radio in 5G networks. It begins with describing the evolution of mobile standards from 1G to 4G. It then introduces the concepts of 5G and cognitive radio. The key points are:
- 5G will provide very high data rates up to 1 Gbps and connect many more devices.
- Cognitive radio can improve spectrum efficiency by allowing unlicensed users to access licensed spectrum holes.
- The document proposes a cognitive radio based 5G network that can integrate various wireless technologies and help manage network complexity using cognitive radio's abilities.
THE UWB SOLUTION FOR MULTIMEDIA TRAFFIC IN WIRELESS SENSOR NETWORKSijwmn
Several researches are focused on the QoS (Quality of Service) and Energy consumption in wireless Multimedia Sensor Networks. Those research projects invest in theory and practice in order to extend the spectrum of use of norms, standards and technologies which are emerged in wireless communications.
The performance of these technologies is strongly related to domains of use and limitations of their characteristics. In this paper, we give a comparison of ZigBee technology, most widely used in sensor networks, and UWB (Ultra Wide Band) which presents itself as competitor that present in these work better results for audiovisual applications with medium-range and high throughput.
This document is a project proposal for implementing wireless data communication using Zigbee technology. It discusses using Zigbee modules to encrypt data from a keypad, transmit it wirelessly between two PCs up to 70 meters away, then decrypt and display the data. The objectives are to provide reliable and secure data transmission with low power consumption. Zigbee is suitable because it supports mesh networking, low data rates, long battery life, and security. The proposal reviews related work using Zigbee in wireless sensor networks for agriculture and discusses how Zigbee can benefit applications in hospitals, homes, and industry. The scope is limited to transmitting encrypted data between two PCs using Zigbee modules.
This document discusses using cognitive radio networks to enable smart grid applications. It begins by introducing smart grids and their need to overcome challenges in aging infrastructure and growing energy demands. It then discusses cognitive radio networks, which can opportunistically access licensed spectrum without interfering with licensed users. The document outlines the key components of cognitive radio networks and smart grids, and proposes using cognitive radio networks to enable smart grid applications at the home area network, neighborhood area network, and wide area network levels. Specifically, it suggests cognitive radio technologies could manage spectrum sharing among smart meters and grid components to improve efficiency and flexibility of smart grid operations.
1) The document expresses gratitude to the author's guide and friends for their support and guidance in completing a thesis.
2) It provides an overview of the xMax technology, which can be used for wired or wireless communication and improve range and battery life. It uses a hybrid of narrowband and wideband modulation.
3) It discusses xMax's network architecture, which provides voice and data services through base stations, an access gateway, and backhaul links at a lower cost than traditional networks through techniques like SIP compression.
Wireless Data Communication Techniques to Coordinate Distributed Rooftop PVs ...TELKOMNIKA JOURNAL
A necessity of the availability of communication network to provide data transfer amongst the
coordinated single-phase rooftop photovoltaic (PV) in unbalanced three-phase low voltage (LV) feeder is
essential since fetching data within the sensor of each PV unit requires real-time measurement and
reliable data exchange within smart grid (SG), loads and other PV units. The main objective of this paper is
to model the popular Wi-Fi, WiMax and ZigBee wireless data communication techniques into algorithms
using numerical analysis. Those communication technologies have low cost and low power consumption.
The benefits and drawbacks of those considered wireless data communications are shown as the required
data that transferred and appropriate coding is also proposed. The number of transmitted symbols and the
processing time delay of the proposed data coding are numerically analyzed, the results indicated that the
100% penetration level of PV that resulted higher injected reactive power back into the networks is able to
be overcome since the coordinated PVs along the feeder is communicating to lower the unbalanced
voltage profile.
Wireless communication is a communication method that utilizes the characteristics of electromagnetic wave signals propagating in free space to exchange information. Wireless communication technology has many advantages and low cost. Wireless communication technology does not need to establish physical lines, and it does not need a lot of manpower to lay cables. Moreover, wireless communication technology is not limited by the industrial environment, and it has strong ability to resist environmental changes. Also relatively easy, compared to the traditional wired communication setup and maintenance, wireless network maintenance can be completed through remote diagnosis, more convenient; scalability is strong, when the network needs to be expanded, wireless communication does not need to expand the wiring; flexibility, wireless The network is not limited by the terrain of the environment, and when the use environment changes, the wireless network can be adapted to the requirements of the new environment with little adjustment.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Cognitive Radio (CR) is an adaptive, intelligent radio and network technology that can automatically detect available channels in a wireless spectrum and change transmission parameters enabling more communications to run concurrently and also improve radio operating behavior.
Impact of Frequency Offset on Interference between Zigbee and Wifi for Smart ...IOSR Journals
Abstract: The Zigbee is a low cost communication technology used for low data rate communication system such as industrial automation etc. Because of its low complexity it is widely adopted for many applications. But the utilization of the same spectrum band by the WLAN system causes interference between both the systems. The proposed approach presents an analysis of this interference effect on Zigbee system when operated with WLAN sources at different distances and different power. It also analyzes the effect when a frequency offset is established between both systems. The simulation results shows that a small offset can provide sufficient improvement in the performance. Keywords: Smart Grids, Zigbee Network, Mesh Network, Wireless LAN (WLAN), BER
This document discusses wireless personal area networks (WPANs) and some common WPAN technologies used within short distances of less than 5 meters. It describes Bluetooth, which was originally proposed in 1998 for short-range wireless applications between devices like phones and cameras. Bluetooth uses frequency hopping spread spectrum in the 2.4 GHz band. ZigBee is also discussed as dealing with very low data rates but long battery life for applications like wireless sensor networks.
Effects of Shadowing on LoRa LPWAN Radio Links IJECEIAES
LoRaWAN is a long-range, low-power, wireless telecommunications method; expected to play a big role for the Internet of Things. End appliances use LoRaWAN through a single wireless hop to communicate with gateways linked to the Internet that function as transparent bridges relaying messages amongst these end-devices and a central network server. This technology youtes a combination of extended range, low power utilization and protected data communication and is gaining significant traction in IoT networks being deployed by wireless network operators. However, no comprehensive evaluation of the technology exists in the open literature. The main intention of this paper is to investigate the effects of shadowing on LoRaWAN links and analyze the performance in terms of packet loss ratio for different physical layer settings. Results indicate large differences in performance when shadowing is taken into consideration upsetting the expected performance tremendously.
This document provides a comparative study of Bluetooth, 802.11, and HIPERLAN wireless standards. It begins with an introduction to wireless LAN standards and classifications of wireless LANs. It then discusses key aspects of various wireless standards, including IEEE 802.11, HIPERLAN, and Bluetooth. It compares their operating frequencies, data transmission rates, and other technical specifications. The document also includes figures illustrating wireless network architectures and standards. In conclusion, it provides a brief literature review on topics related to planning, designing, and implementing wireless local area networks.
LoRaWAN technology uses unlicensed spectrum and provides long range connectivity for IoT devices. It uses chirp spread spectrum modulation and supports different data rates and frequency bandwidths depending on regional regulations. LoRaWAN networks have a star topology with IoT devices connecting to gateways and using a central network server. IoT devices are classified into different classes depending on their communication needs, with Class A devices allowing bidirectional communication through scheduled bursts.
Frontiers of Wireless and Mobile CommunicationsSai Varrshini
This document discusses emerging wireless technologies and their impact. It provides an overview of key technologies like MIMO, cooperative communications, and dynamic spectrum access. It summarizes the evolution of radio technologies from 2G to 4G standards and increasing link speeds. It also examines short-range wireless technologies and research challenges in building cognitive radios and software-defined radios to efficiently utilize spectrum.
An overview of cognitive radio, comparison of cognitive radio vs. conventional radio, real-world applications for cognitive radio networks, how cognitive radios improve spectrum efficiency and address the wireless spectrum shortage.
The document provides an introduction to wireless sensor networks, including key terms and concepts. It discusses motes, which are low-power devices that integrate sensing, processing and radios. The document also covers operating systems like TinyOS that help program sensor networks, as well as advances in technology like MEMS, VLSI and wireless standards that enabled the development of sensor networks. Finally, it previews topics to be covered in the next class, including the differences between telemetry systems and sensor networks.
Dynamic frequency allocation in femtocells-based systems: algorithms and perf...Remo Pomposini
This document summarizes the PhD candidate Remo Pomposini's research on dynamic frequency allocation algorithms for femtocell-based systems. It discusses the problem of interference between densely deployed femtocells and proposes using cognitive radio techniques and dynamic frequency selection algorithms to intelligently allocate frequencies. It analyzes the performance of greedy and operator-oriented algorithms through simulations in various network topologies and deployment scenarios. The results show that the greedy algorithm comes closest to optimal frequency assignment and significantly increases the number of active femtocells compared to random assignment.
Cognitive radios are smart radios that can sense their environment and adjust their transmission parameters accordingly. They were first proposed in 1999 to more efficiently utilize limited radio spectrum. Cognitive radios operate in a cycle of spectrum sensing, decision, sharing, and mobility. They can access licensed spectrum as secondary users as long as they do not interfere with primary users. This allows for increased spectrum utilization. Cognitive radios have characteristics of cognitive capability, reconfigurability, and self-organization. They enable applications such as cognitive mesh networks and public safety networks through techniques like dynamic spectrum management.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document discusses cognitive radio in 5G networks. It begins with describing the evolution of mobile standards from 1G to 4G. It then introduces the concepts of 5G and cognitive radio. The key points are:
- 5G will provide very high data rates up to 1 Gbps and connect many more devices.
- Cognitive radio can improve spectrum efficiency by allowing unlicensed users to access licensed spectrum holes.
- The document proposes a cognitive radio based 5G network that can integrate various wireless technologies and help manage network complexity using cognitive radio's abilities.
THE UWB SOLUTION FOR MULTIMEDIA TRAFFIC IN WIRELESS SENSOR NETWORKSijwmn
Several researches are focused on the QoS (Quality of Service) and Energy consumption in wireless Multimedia Sensor Networks. Those research projects invest in theory and practice in order to extend the spectrum of use of norms, standards and technologies which are emerged in wireless communications.
The performance of these technologies is strongly related to domains of use and limitations of their characteristics. In this paper, we give a comparison of ZigBee technology, most widely used in sensor networks, and UWB (Ultra Wide Band) which presents itself as competitor that present in these work better results for audiovisual applications with medium-range and high throughput.
This document is a project proposal for implementing wireless data communication using Zigbee technology. It discusses using Zigbee modules to encrypt data from a keypad, transmit it wirelessly between two PCs up to 70 meters away, then decrypt and display the data. The objectives are to provide reliable and secure data transmission with low power consumption. Zigbee is suitable because it supports mesh networking, low data rates, long battery life, and security. The proposal reviews related work using Zigbee in wireless sensor networks for agriculture and discusses how Zigbee can benefit applications in hospitals, homes, and industry. The scope is limited to transmitting encrypted data between two PCs using Zigbee modules.
This document discusses using cognitive radio networks to enable smart grid applications. It begins by introducing smart grids and their need to overcome challenges in aging infrastructure and growing energy demands. It then discusses cognitive radio networks, which can opportunistically access licensed spectrum without interfering with licensed users. The document outlines the key components of cognitive radio networks and smart grids, and proposes using cognitive radio networks to enable smart grid applications at the home area network, neighborhood area network, and wide area network levels. Specifically, it suggests cognitive radio technologies could manage spectrum sharing among smart meters and grid components to improve efficiency and flexibility of smart grid operations.
1) The document expresses gratitude to the author's guide and friends for their support and guidance in completing a thesis.
2) It provides an overview of the xMax technology, which can be used for wired or wireless communication and improve range and battery life. It uses a hybrid of narrowband and wideband modulation.
3) It discusses xMax's network architecture, which provides voice and data services through base stations, an access gateway, and backhaul links at a lower cost than traditional networks through techniques like SIP compression.
Wireless Data Communication Techniques to Coordinate Distributed Rooftop PVs ...TELKOMNIKA JOURNAL
A necessity of the availability of communication network to provide data transfer amongst the
coordinated single-phase rooftop photovoltaic (PV) in unbalanced three-phase low voltage (LV) feeder is
essential since fetching data within the sensor of each PV unit requires real-time measurement and
reliable data exchange within smart grid (SG), loads and other PV units. The main objective of this paper is
to model the popular Wi-Fi, WiMax and ZigBee wireless data communication techniques into algorithms
using numerical analysis. Those communication technologies have low cost and low power consumption.
The benefits and drawbacks of those considered wireless data communications are shown as the required
data that transferred and appropriate coding is also proposed. The number of transmitted symbols and the
processing time delay of the proposed data coding are numerically analyzed, the results indicated that the
100% penetration level of PV that resulted higher injected reactive power back into the networks is able to
be overcome since the coordinated PVs along the feeder is communicating to lower the unbalanced
voltage profile.
Wireless communication is a communication method that utilizes the characteristics of electromagnetic wave signals propagating in free space to exchange information. Wireless communication technology has many advantages and low cost. Wireless communication technology does not need to establish physical lines, and it does not need a lot of manpower to lay cables. Moreover, wireless communication technology is not limited by the industrial environment, and it has strong ability to resist environmental changes. Also relatively easy, compared to the traditional wired communication setup and maintenance, wireless network maintenance can be completed through remote diagnosis, more convenient; scalability is strong, when the network needs to be expanded, wireless communication does not need to expand the wiring; flexibility, wireless The network is not limited by the terrain of the environment, and when the use environment changes, the wireless network can be adapted to the requirements of the new environment with little adjustment.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Cognitive Radio (CR) is an adaptive, intelligent radio and network technology that can automatically detect available channels in a wireless spectrum and change transmission parameters enabling more communications to run concurrently and also improve radio operating behavior.
Impact of Frequency Offset on Interference between Zigbee and Wifi for Smart ...IOSR Journals
Abstract: The Zigbee is a low cost communication technology used for low data rate communication system such as industrial automation etc. Because of its low complexity it is widely adopted for many applications. But the utilization of the same spectrum band by the WLAN system causes interference between both the systems. The proposed approach presents an analysis of this interference effect on Zigbee system when operated with WLAN sources at different distances and different power. It also analyzes the effect when a frequency offset is established between both systems. The simulation results shows that a small offset can provide sufficient improvement in the performance. Keywords: Smart Grids, Zigbee Network, Mesh Network, Wireless LAN (WLAN), BER
This document discusses wireless personal area networks (WPANs) and some common WPAN technologies used within short distances of less than 5 meters. It describes Bluetooth, which was originally proposed in 1998 for short-range wireless applications between devices like phones and cameras. Bluetooth uses frequency hopping spread spectrum in the 2.4 GHz band. ZigBee is also discussed as dealing with very low data rates but long battery life for applications like wireless sensor networks.
Effects of Shadowing on LoRa LPWAN Radio Links IJECEIAES
LoRaWAN is a long-range, low-power, wireless telecommunications method; expected to play a big role for the Internet of Things. End appliances use LoRaWAN through a single wireless hop to communicate with gateways linked to the Internet that function as transparent bridges relaying messages amongst these end-devices and a central network server. This technology youtes a combination of extended range, low power utilization and protected data communication and is gaining significant traction in IoT networks being deployed by wireless network operators. However, no comprehensive evaluation of the technology exists in the open literature. The main intention of this paper is to investigate the effects of shadowing on LoRaWAN links and analyze the performance in terms of packet loss ratio for different physical layer settings. Results indicate large differences in performance when shadowing is taken into consideration upsetting the expected performance tremendously.
This document provides a comparative study of Bluetooth, 802.11, and HIPERLAN wireless standards. It begins with an introduction to wireless LAN standards and classifications of wireless LANs. It then discusses key aspects of various wireless standards, including IEEE 802.11, HIPERLAN, and Bluetooth. It compares their operating frequencies, data transmission rates, and other technical specifications. The document also includes figures illustrating wireless network architectures and standards. In conclusion, it provides a brief literature review on topics related to planning, designing, and implementing wireless local area networks.
LoRaWAN technology uses unlicensed spectrum and provides long range connectivity for IoT devices. It uses chirp spread spectrum modulation and supports different data rates and frequency bandwidths depending on regional regulations. LoRaWAN networks have a star topology with IoT devices connecting to gateways and using a central network server. IoT devices are classified into different classes depending on their communication needs, with Class A devices allowing bidirectional communication through scheduled bursts.
Frontiers of Wireless and Mobile CommunicationsSai Varrshini
This document discusses emerging wireless technologies and their impact. It provides an overview of key technologies like MIMO, cooperative communications, and dynamic spectrum access. It summarizes the evolution of radio technologies from 2G to 4G standards and increasing link speeds. It also examines short-range wireless technologies and research challenges in building cognitive radios and software-defined radios to efficiently utilize spectrum.
Objective is to include the brief insight on 5G network architecture and standard progress, Accumulated it from different paper/journal, vendor’s white paper and different blog.
Ppt on smart small cell with hybrid beamforming for 5 gBhaskar Gurana
This document proposes a smart small cell concept using hybrid beamforming to enhance network capacity for 5G. It discusses requirements for 5G including high data rates and connections. Hybrid beamforming combines analog and digital beamforming to reduce complexity. The document describes a testbed using SDR and antenna array to implement 3D hybrid beamforming in small cells. System simulations using a 3D ray tracing tool show gains over LTE networks. Evaluation results examined link and system performances, and the conclusion is the smart small cell can support 5G networks based on SDR testbed and simulation results.
Low-power wide area networking technology offers long-range communication, enabling new types of IoT services. LoRaWAN is one of the most adopted solutions, providing ubiquitous connectivity for outdoor applications. However, its capabilities and limitations are not well understood. The authors provide an impartial overview of LoRaWAN's limitations to avoid unrealistic expectations, discussing use cases where it works and does not work, and listing open research questions.
This document provides an overview of 4G wireless systems. It discusses key features such as support for multimedia services, an all-IP packet switched network, and improved quality of service. The implementation of 4G is described as using a single worldwide IP standard for control, video, and voice. Wireless technologies enabled in 4G include OFDM, UWB, smart antennas, and adaptive modulation. Applications mentioned include use in vehicles, public safety, traffic control, and route selection for first responders. Issues addressed are choosing the optimal access technology and designing an IP architecture to support mobility.
Analysis of Handoff techniques used for hybrid networks: cellular/WLAN IJORCS
Most real life networks are hybrid networks. A hybrid network combines the best features of two or more networks. In networking terminology, a hybrid network according to “Information Technology control and Audit” are reliable and versatile. They provide large numbers of connections and data transmission paths to users. These hybrid networks may be treated as network nodes for analysis purpose. The two radio access technologies (RATs) are considered with cellular/WLAN depending on whether it is voice/ data, video. For observing practical result, some setups are required in laboratory which includes interface from personal computer to mobile terminal and vice-versa. The network simulator (Ns-2) is used for analysis purpose. The results shows the parameters like energy good put, Bandwidth utilization, packet delivery ratio, energy good put and energy consumed are improved after using hybrid networks.
Mobile Networking and Ad hoc routing protocols validationIOSR Journals
This document discusses mobile networking and ad hoc routing protocols. It begins with an overview of cellular phone networks and their growth in usage. It then describes mobile ad hoc networks and some of the challenges in designing routing protocols for them. The document evaluates two model checking tools, SPIN and UPPAAL, and discusses their ability to verify properties of ad hoc routing protocols through formal validation methods.
VHDL Implementation of FPGA Based OFDM Modem for Wireless ApplicationsEditor IJCATR
This document describes the VHDL implementation of an FPGA-based OFDM modem for wireless applications. It discusses Orthogonal Frequency Division Multiplexing (OFDM) and how it can be used for high-speed wireless communications. The document outlines the basic blocks of an OFDM modulator and demodulator system, including QAM/PSK modulation, serial to parallel conversion, inverse fast Fourier transform (IFFT), and how these can be implemented using VHDL on an FPGA for applications such as software defined radio. It provides a block diagram of the OFDM modem and discusses the advantages of implementing the design using a field programmable gate array.
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SCALABILITY CONCERNS OF CHIRP SPREAD SPECTRUM FOR LPWAN APPLICATIONS
1. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
DOI : 10.5121/ijasuc.2019.10101 1
SCALABILITY CONCERNS OF CHIRP SPREAD
SPECTRUM FOR LPWAN APPLICATIONS
Aiju Thomas1
and N V Eldhose2
1
School of Technology and Applied Science, M G University, Kottayam, India
2
M G University, Kottayam, India
ABSTRACT
Divergent modulation schemes have been proposed for the Internet of Things (IoT). Low Power Wide Area
Networks (LPWAN) technologies are gaining unprecedented acceptance in IoT application of sensor
networks. Chirp Spread Spectrum (CSS) is a prominent modulation technique proposed for LPWAN. Chirps
can traverse long distance and are resilient to noise and Doppler effects. Noise resilience along with
transmission range and low power requirement makes CSS a preferred modulation scheme for sensor
networks. LoRaWANTM
, with its physical (PHY) layer using CSS, has emerged as the widely accepted
LPWAN solution. By using CSS modulation with orthogonal spreading factors (SF), LoRa offers wide
coverage to LPWAN applications while supporting a high volume of devices. However, scalability
performance of CSS has not been inadequately modeled. As with the suitability of the modulation scheme,
there are concerns on how chirps interact with the surrounding as the number of deployments bursts out
into higher volumes. We evaluate CSS at ISM band 868 MHz for spreading factor 7 to 12 at bandwidth 125
kHz for performance and scalability. Simultaneous transmissions were simulated with repeated iterations
and conclusions are arrived on collisions rate, packet error rate, and bit error. Suitability of using CSS for
sensor networks for future deployments is commended.
KEYWORDS
LoRA, LPWAN, Sensor networks, CSS, Chirp Spread Spectrum, Packet error, collision
1.INTRODUCTION
Internet of Things (IoT) is a paradigm that creates a panoply of interconnected devices.
Widespread deployment of IoT imposes complexity in communication and heterogeneity among
devices which communicate over the Internet. The current deployments of things are in the order
of 50 billion and by 2020 and will encompass 1000 times more connected devices, all with
different requirements. There are concerns about how devices will interact with the surrounding
and among themselves. This is however difficult to assume as today’s network is limited with its
ability to address the requirements of future deployments. The scalability of networks is a concern
as to cope with the ever-growing number of devices [1]. Machine to Machine (M2M)
communication as part of IoT is characterized by divergent modulation schemes. Modulation
schemes are application specific, depends on the volume of data handled and range. A
surveillance camera is required to deliver a huge volume of data, whereas applications like
metering handle a small amount of data while being stationary. IoT applications such as sensor
networks are often battery powered and require scalable low power wireless technologies. Low
Power Wide Area Networks (LPWAN) has been proposed to address the needs of long-range and
low-power IoT applications in the field of sensor networks.
Wireless sensor networks currently practice cellular-based technologies or multi-hop short-range
technologies for LPWAN [2]. Devices or things use dedicated protocol stack to cope with the
2. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
2
constraints of an end device. Constraints are set on power usage, range, computing capability, and
bandwidth. In these networks, one of the things needs to connect to the internet through an
internet protocol (IP) forming gateway whereas all the other form network among them in star or
mesh topology. Applications and services are deployed at the top of the protocol stack which
either runs locally or as part of the cloud.
There are standards that operate mostly at 2.4 GHz and optionally in the 868/915 MHz,
unlicensed frequency bands used to connect things. Prominent among them are
• Near Field Communications (NFC) for short range applications;
• Radio Frequency Identification (RFID) systems for active or passive networks;
• ZigBeeTM
, 6LoWPAN, Thread-based systems under IEEE 802.15.4 standards;
• BluetoothTM
, Bluetooth Low Energy (BLE)TM
;
• IEEE 802.11 based Wi-FiTM
;
Majority of these protocol use IEEE 802.15.4 based standard. These standards are weak in
penetration capability and suffer heavy bandwidth interference. These technologies cannot be
deployed for sensor networks due to range limitations. Another popular alternative is cellular
networks connecting devices to the IoT gateway. The devices running on cellular networks use
power-hungry algorithms for signal decoding. Deployments of such networks are expensive and
the difficulty in device certification limits their application for sensor networks. Cellular networks
are minimal in success addressing to LPWAN space despite its formidable presence. 2G cellular
technologies are fading out: there are 30 million 2G base stations in the US alone which are to be
orphaned [3]. 4G LTE or 5G with much more spectral efficiency is about to replace 2G
technologies, leaving the carriers with no choice accepting consumer demand for high data speed.
4G and 5G networks cannot ensure scalability considering the volume of future deployment.
LPWAN which utilize the sub-GHz band and are can provide several kilometres of outdoor
coverage. There have been efforts to reduce the bandwidth requirement for IoT devices. Driver
encapsulation [4] techniques reduce bandwidth requirement hence enhance spectral efficiency of
devices. The paper is organized in three sessions. Technologies related to LPWAN are discussed
in session 2. Session 3 covers mathematical representation of CSS to aid simulation. Session 4
covers simulation environment and results.
2. RELATED TECHNOLOGIES
In order to help the reader better understand LPWAN, three prominent technologies supporting
LPWAN for sensor networks are presented in this session.
2.1. SIGFOXTM
Sigfox was proposed for the IoT market in 2009. They have a distinct market share since then.
Sigfox operates in the 200 kHz using the ultra narrow band modulation [3]. Each message is 100
Hz wide and transferring at 100 or 600 bits per second, depending on the region. Sigfox can
achieve long range while being robust against noise. An uplink message has up to 12 bytes
payload and takes an average 2s over the air to reach the base stations which monitors the
spectrum for Ultra Narrow Band (UNB) signals. For 12-byte data payload, a Sigfox frame uses 26
bytes in total [5]. The payload allowance in downlink messages is 8 bytes. A device is not
attached to any specific base station like cellular networks. The broadcast messages are received
by an average of three base stations in the range, and necessary approximations are made to
3. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
3
decode the correct data. The first released technology supported only unidirectional uplink,
however, bidirectional communication is now available [3]. Sigfox claims that each gateway can
handle up to a million of connected objects, with a coverage area of 30–50 km in rural and 3–10
km in urban. But deployment to test the claim in terms of scalability is not achieved so far.
Evaluation of network scalability cannot be performed as the technical details are kept
unpublished as the protocol is proprietary in nature.
2.2. INGENUTM
Ingenu is a preparatory LPWAN which has been around for Machine to Machine (M2M),
Wireless Sensor Networking (WSN) and IoT [6]. Random Phase Multiple Access (RPMATM)
uniquely addresses hundreds of IoT devices. RPMA was designed to provide secure LPWAN
solutions at 2.4 GHz band pioneering the 802.15.4k [7] standard. Despite the operating band at
2.4 GHz, the robustness of physical layer design can provide over long-range propagation under
the most challenging RF environments.
2.3. LORATM
LoRa is a proprietary spread spectrum modulation scheme which is a derivative of CSS. LoRa
trades data rate for sensitivity within a fixed channel bandwidth [8]. It implements a variable data
rate, utilizing orthogonal spreading factors, which allows the system designer to trade data rate for
range or power and optimize network performance at a constant bandwidth. LoRa uses wideband
linear frequency modulated pulses [9] whose frequency increases or decreases over a certain
amount of time to encode information. This method will substantially increase receiver
sensitivity due to the processing gain of the spread spectrum technique and exhibits a high
tolerance to frequency misalignment between receiver and transmitter.
3. CHIRP SPREAD SPECTRUM
Chirps are linear frequency modulated wideband pulses that are characterized by low power
consumption, resilience to fading and Doppler effects. CSS combined with digital modulation
schemes such as Binary Orthogonal Keying (BOK), Quadrature Phase Shift Keying (QPSK) and
Differential Phase Shift Keying (DQPSK) can deliver better performance in Bit Error Rate (BER)
[10]. Chirp Spread Spectrum (CSS) was initially proposed by Winkler for communication [11]
and was applied to digital communication by Berni [12]. CSS is now being adopted for sensor
networks due to its low power requirement, resilience to channel degradation by multipath fading
and Doppler effects. IEEE 802.15.4 adopts CSS for Low Rate Wireless Personal Area Networks
(LR – WPAN) for range and mobility. IEEE 802.15.4a standard [13] specifies CSS in two
optional physical layers to support extended range.
• Ultra Wide Band (UWB) model, spanning from 2 to 10 GHz frequency.
• UWB model for the frequency range from 100-1000 MHz
Narrowband frequency located within the mentioned range can be derived by a simple bandpass
filtering. IEEE 802.11ah [14] is an extended range wireless protocol standard in sub-Gigahertz
ISM band (863–868 MHz in Europe, 755–787 MHz in China and 902–928 MHz in North
America) which minimize contention by extending their reach with low transmitted power. Radio
propagation at these frequencies allows signals to travel greater distances, opens up opportunities
to use with IoT. Semtech’s LoRa™ [9] provides low power, low-cost long-range communication
4. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
4
for IoT applications. LoRa™ utilize chirp spread spectrum for long-range communication. In
LoRaWAN™ transceivers communicate with LoRa™ gateway which connects to the internet.
This paper examines LPWAN sensor networks in terms of Bit Error Ratio (BER), the number of
packet collisions and packet error rate using MATLAB™. Evaluation is perfumed considering
CSS as used LoRa physical layer. Modulated chirp signals were transmitted through an Additive
White Gaussian Noise (AWGN) channel and evaluated for performance by varying Signal to
Noise Ratios (SNR). Decoded signals are iterated manifold for consistency in results. A detailed
mathematical model for CSS is presented in forthcoming sessions. Packet error rate and the
number of collisions were analyzed with considerable numbers of sensors communicating
simultaneously. Conclusions are drawn on scalability and range of CSS in LPWAN sensor
networks.
3.1. MATHEMATICAL REPRESENTATION OF CHIRPS
3.1.1. LINEAR CHIRPS
Constant amplitude linear chirps are denoted as [6] [15] [9]
𝑥(𝑡) = 𝐴 cos(𝜃(𝑡)) (1)
where: θ(t) is the phase for a given time t
A is the amplitude of the chirp which is constant for a given chirp duration T sec outside
which, A is zero.
Instantaneous frequency of the chirp can be represented as
𝜔(𝑡) =
𝑑
𝑑𝑡
(𝜃(𝑡))
(2)
Time linearity of chirp can be achieved by making phase quadratic
𝜃(𝑡) = 2𝜋µ𝑟𝑡2
+ 2πf0t + ϕ (3)
Instantaneous angular frequency which is the derivative of phase θ(t) becomes
𝜔𝑖(𝑡) =
𝑑
𝑑𝑡
𝜃(𝑡) = 4𝜋µ𝑡 + 2𝜋𝑓0
(4)
Instantaneous frequency in Hz is given as
𝑓𝑖 = 2µ𝑡 + 𝑓0 (5)
In equation (5) frequency varies linearly with time with starting frequency at 𝑓0 . The rate of
frequency change for chirp duration T secs is given as
𝑘 = 2µ𝑡 =
(𝑓1 − 𝑓0)
𝑇
(6)
5. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
5
Sinusoidal sweeping frequency from 𝑓0 to 𝑓1 with phase as derivative 2𝜋(𝑘𝑡 + 𝑓0) is given as
cos(2𝜋
𝑘
2
𝑡2
+ 2𝜋𝑓0𝑡)
Linear chirp is represented in terms of time varying instantaneous frequency
𝑥(𝑡) = 𝐴 cos(2𝜋𝑓(𝑡)𝑡 + 𝜙(𝑡)) (7)
where
𝑓(𝑡) =
𝑘
2
𝑡 + 𝑓0
In equation (2) if 𝜃(𝑡) is constant then frequency is zero, if 𝜃(𝑡) is linear then frequency is
constant and if 𝜃(𝑡) is quadratic then frequency is linear.
3.1.2. Chirp Spread Spectrum as used in LoRa
LoRa utilizes CSS in its physical layer symbol modulation. Symbols are chirped using linear
chirps. Chirps are spread to the entire spectrum of the carrier. CSS maintains constant
timing and frequency offsets, reducing the complexity of receiver [9].
Spectral spreading is achieved by varying 𝜙(𝑡) of the chirp signal. Specific time function of
raw chirp 𝑓(𝑡) exhibits linearity as
• Increases from
−𝑏𝑤
2
to
𝑏𝑤
2
for up chirps.
• Decreases from
𝑏𝑤
2
to
−𝑏𝑤
2
for down chirps.
Where: 𝑏𝑤 is the spectral bandwidth in Hz.
Figure 1. Chirp modulation of nth
symbol
6. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
6
𝑓(𝑡) in terms of chirp duration 𝑇𝑠 and 𝑏𝑤 is given as
𝑓(𝑡) = ±
𝑏𝑤
𝑇𝑠
𝑡
(8)
Bandwidth and symbol period are related as
𝑇𝑠 =
2𝑆𝐹
𝑏𝑤
𝑠𝑒𝑐𝑠
(9)
Where 𝑆𝐹 the spreading factor ∈ [7,8,9,10,11,12]
Symbol rate 𝑅𝑠 is given as
𝑅𝑠 =
𝑏𝑤
2𝑆𝐹
=
1
𝑇𝑠
(10)
Data rate 𝑅𝑏 is derived as
𝑅𝑏 = 𝑆𝐹
1
2𝑆𝐹
𝑏𝑤
=
𝑆𝐹
𝑇𝑠
That is chirp rate 𝑅𝑏 which is equal to data rate is given as
𝑅𝑏 = 𝑅𝑠2𝑆𝐹
𝑐ℎ𝑖𝑟𝑝𝑠 /𝑠𝑒𝑐 (11)
Equation 11 suggests that symbol rate R_s varies inversely with spreading factor SF. Noise
resilience increases with enhanced SF. Thus by utilizing CSS with higher SF can enhance the
range of transmission. Robustness of communication in terms of Bit Error Rate (BER) can be
improved by using a suitable channel coding algorithm. Though LoRa protocol layers are kept
unpublished, the possibility of using hamming code (8,4) are revealed in many discussions.
Let us assume N set of symbols, chirp associated with any symbol 𝑛, 𝑛 ∈ [0, 𝑁 − 1] is unique.
All the N chirps are orthogonal to each other and can be retrieved without intersymbol
interference. Chirps for any symbol 𝑛 can be achieved by delaying 𝑓(𝑡) by
𝜏𝑛 =
𝑛
𝑏𝑤
𝑠𝑒𝑐𝑠 (12)
Figure 1 shows symbol 𝑛 modulated using up chirps delayed by 𝜏𝑛.
4. PERFORMANCE EVALUATION
Remote deployed sensor networks are constrained in energy, reliability, processing capability and
communication range. Majority of applications demand little or no direct human intervention.
When thousands of sensors are deployed, frequent replacement of batteries itself is laborious [14].
In order to save power, these devices are kept in sleep mode and awakened upon alerted or
scheduled. In this simulated version of CSS, preambles up chirps are transmitted by the remote
machine which intends a communication to the network. Simple filter circuits trigger interrupt
[15].
7. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
7
4.1. SIMULATION ENVIRONMENT
An equivalent baseband model has been created for up and down chirps for error-free simulations
of CSS. Modulated chirps were generated through linear phase variations keeping the amplitude
constant satisfying equation (8). Eight preamble chirps indicate the beginning of package
followed by two down chirps for synchronization. Symbols are generated from a binary
combination of SF [16]. Each symbol is a unique chirp orthogonal to each other. In order to
retrieve symbols at the receiver without inter symbol interference received signals are multiplied
by orthogonal down chirps. In figure 1 symbol n is modulated as chirps from [
−𝑇𝑠
2
,
𝑇𝑠
2
].
Chirps are spread as
𝑓𝑛(𝑡) =
𝑏𝑤
𝑇𝑠
(𝑡 − 𝜏) + 𝑏𝑤 for 𝑡 ∈ [−
𝑇𝑆
2
, −
𝑇𝑆
2
+
𝑛
𝑏𝑤
]
𝑓𝑛(𝑡) =
𝑏𝑤
𝑇𝑠
(𝑡 − 𝜏) for 𝑡 ∈ [−
𝑇𝑆
2
+
𝑛
𝑏𝑤
,
𝑇𝑆
2
] (13)
Figure 2. Coding and decoding process of CSS
4.2. SIMULATION RESULTS
Figure 3 shows chirps generated for 100 symbols which are transmitted with 8 preambles up
chirps and two synchronizing chirps. The generated chirps were transmitted through the AWGN
channel with Signal to Noise Ratio (SNR) 0db. Received signals after band pass filtering were
multiplied with orthogonal down chirps, to receive signal as shown in figure 4.
Fast Fourier Transform (FFT) performed on
Figure 3. 8 preamble, 2 sync and
100 symbols.
Figure 4. After multiplication with
orthogonal chirps at SNR 0db
8. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
8
received signals which were transmitted through AWGN channel with SNR 0db and -20db are
shown in figure 5 and figure 6 respectively.
On comparing FFT of spectrum received at SNR 0db and -20 dB, even though noise level is very
high at -20 dB, with SF = 10, clarity in peaks corresponding to symbols are observed. Figure 7
shows the simulated performance plot of CSS prepared for SF = 7 to 12, with Bandwidth (BW)
and sampling frequency are selected as 125kHz. With 8 preamble and 2 synchronization chirps, a
total of 27720 bits were decoded after being sent through AWGN channel for SNR from -40db to
0db. Bit Error Rates (BERs) were computed for 100 iterations.
Figure. 7: Plot of SNR vs BER for SF 7 to 12
Spectrograms of packet collisions, for a time span of 60 seconds at a time interval of 10
milliseconds are shown in figure 8. Evaluation is made with 6 channels and 500 devices
transmitting simultaneously for spreading factor 7 to 12. At a bandwidth of 125 kHz at ISM band
Figure 5. FFT performed after multiplying
with orthogonal chirps (transmitted at SNR
= 0dB and SF = 10)
Figure 6. FFT performed after multiplying
with orthogonal chirps (transmitted at SNR =
-20dB and SF =10)
9. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
9
868.7MHz to 869.2 MHz, it is observed that packet collisions are higher at SF = 11 and 12
compared with lower SFs.
Figure 8. Packet collisions with 500 sensors transmitting randomly for 60 seconds at 125kHz bandwidth.
Collisions occurred when data packets are transmitted randomly at 10 msec interval with steady
increasing packet rate per minute are shown in figure 9. Number of collisions and percentage
packet error rate vs number of bytes per minute are plotted.
Figure 9. Plot of number of collisions, packet error rate in percentage and number of bytes per minute with
1000 devices transmitting simultaneously with random spreading factor.
The plot of SNR vs. BER for SF 7 to 12 reveals the superior performance of CSS at a high noise
level. Acceptable level of BER is observed from -17db at SF = 7 to -30db at SF = 12. Extended
range can be achieved by enhancing spreading factor as shown in equation 11 but the bit rate is
compromised. Adversely when more devices communicate simultaneously at higher packet rate,
there are exponential increases in collisions and packet error. An optimum value can be observed
as 200 bytes per minute with 1000 device transmit simultaneously. Most of the sensor networks
in IoT application needs ultra low bit rate. A data rate of 200 bytes per minute is a substantially
10. International Journal of Ad hoc, Sensor & Ubiquitous Computing (IJASUC) Vol.10, No.1, February 2019
10
high value for sensor networks. Even though Chirp Spread Spectrum can efficiently be deployed
for setting up ad hoc sensor networks for long-range concerns exists as the number of
deployments keeps on increasing, there shall be deterioration in performance due to packet
collisions at higher spreading factor. Alternate modulation schemes need to be considered for the
massive deployment of LPWAN.
5. CONCLUSIONS
We analyzed robustness and noise immunity of CSS as a modulation scheme for the deployment
of LPWAN. We investigated interference among carriers caused by simultaneous transmissions
for collisions. Observations prove better noise immunity of the modulation scheme and
suitability for low power wide area sensor networks. Collisions and packet error rate were plotted
for 1000 devices transmitting simultaneously at varying packet rate. Simulations proved an
exponential increase in collisions and packet error for simultaneous transmissions. Concerns are
justified on the deterioration of performance due to massive deployment. The inherent property of
chirp spread spectrum as energy efficient modulation scheme together with resilience to noise
makes it the best suited for sensor network IoT applications at the ultra-low bit rate. More
investigations need to be made to adopt methods to reduce mutual interference that may cause
due to massive deployment.
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LoRa network under imperfect orthogonality” , IEEE transactions on industrial informatics(early
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(M2M) communication”, International Conference on Control Communication and Computing
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AUTHORS
Aiju Thomas received his Bachelor of Engineering and Masters of Technology in
Electronics and Communication Engineering with specialization in microwave
engineering. He is pursuing his research in the optimization of IoT protocols at M G
University, Kottayam, Kerala, India. With 10 years of industrial experience and 19
years as faculty in Electronics at Polytechnic institute, his field of interest include
industrial and embedded designing.
N V Eldhose received his Bachelor and Masters in Science and Ph.D. degree in Physics. As a research
guide for M G University, Kerala his research interests include ubiquitous computing, wireless sensor
networks, embedded systems, and machine-to-machine communication. He is currently a faculty in
Electronics at School of Technology and Applied Science and is guiding eight research projects currently.