Misplaced Pages

#914085

30-636: LoRaWAN (Long Range Wide Area Network ) defines the communication protocol and system architecture. LoRaWAN is an official standard of the International Telecommunication Union (ITU), ITU-T Y.4480. The continued development of the LoRaWAN protocol is managed by the open, non-profit LoRa Alliance, of which Semtech is a founding member. Together, LoRa and LoRaWAN define a low-power, wide-area (LPWA) networking protocol designed to wirelessly connect battery operated devices to

60-456: A fixed channel bandwidth B {\displaystyle B} ) by selecting the SF, i.e. the amount of spread used. A lower SF corresponds to a higher data rate but a worse sensitivity, a higher SF implies a better sensitivity but a lower data rate. Compared to lower SF, sending the same amount of data with higher SF needs more transmission time, known as time-on-air. More time-on-air means that

90-421: A proprietary spread spectrum modulation that is similar to and a derivative of chirp spread spectrum (CSS) modulation. Each symbol is represented by a cyclic shifted chirp over the frequency interval ( f 0 − B / 2 , f 0 + B / 2 {\displaystyle f_{0}-B/2,f_{0}+B/2} ) where f 0 {\displaystyle f_{0}}

120-432: Is a logarithmic measurement, so adding decibels is equivalent to multiplying the actual power ratios. For a line-of-sight radio system, the primary source of loss is the decrease of the signal power as it spreads over an increasing area while it propagates, proportional to the square of the distance (geometric spreading). The free space loss is easily calculated using Friis transmission equation which states that

150-401: Is called the link margin . A link budget equation including all these effects, expressed logarithmically, might look like this: where: The loss due to propagation between the transmitting and receiving antennas, often called the path loss, can be written in dimensionless form by normalizing the distance to the wavelength: When substituted into the link budget equation above, the result is

180-435: Is not available. In practical situations (deep space telecommunications, weak signal DXing etc.) other sources of signal loss must also be accounted for If the estimated received power is sufficiently large (typically relative to the receiver sensitivity ), which may be dependent on the communications protocol in use, the link will be useful for sending data. The amount by which the received power exceeds receiver sensitivity

210-498: Is the center frequency and B {\displaystyle B} the bandwidth of the signal (in Hertz). The spreading factor (SF) is a selectable radio parameter from 5 to 12 and represents the number of symbols sent per bit and in addition determines how much the information is spread over time. There are M = 2 S F {\displaystyle M=2^{\mathrm {SF} }} different initial frequencies of

240-446: Is to support and promote the global adoption of the LoRaWAN standard for massively scaled IoT deployments, as well as deployments in remote or hard-to-reach locations. Members collaborate in a vibrant ecosystem of device makers, solution providers, system integrators and network operators, delivering interoperability needed to scale IoT across the globe, using  public, private, hybrid, and community networks. Key areas of focus within

270-487: Is unable to maintain the two said advantages of LoRa modulation. Therefore, implementing TR013 enhances LoRaWAN's spectrum efficiency and ensures more reliable device communication, including in congested environments. TR013 is based on the LMAC and is the first industry-academia collaboration of LoRa Alliance to have resulted in a Technical Recommendation. The LoRa Alliance is an open, non-profit association whose stated mission

300-624: The medium access control (MAC) layer protocol, but to improve this, the LoRa Alliance's Technical Recommendation TR013 introduced CSMA-CA , which does not debilitate LoRa's distinctive modulation advantages such as Spreading Factor orthogonality, and the capability for below noise-floor communication. Employing the CAD based CSMA technique specified in TR013 overcomes the limitations of relying on Received Signal Strength (RSS)-based sensing, which

330-646: The physical layer , while other technologies and protocols such as LoRaWAN cover the upper layers. It can achieve data rates between 0.3 kbit/s and 27 kbit/s, depending upon the spreading factor. LoRa is one of the most popular low-power wireless sensor network technologies for the implementation of the Internet of Things, offering long-range communication compared to technologies such as Zigbee or Bluetooth, but with lower data rates. LoRa devices have geolocation capabilities used for trilaterating positions of devices via timestamps from gateways. LoRa uses

SECTION 10

#1732783183915

360-466: The Alliance are Smart Agriculture, Smart Buildings, Smart Cities, Smart Industry, Smart Logistics, and Smart Utilities. Key contributing members of the LoRa Alliance include Actility, Amazon Web Services , Cisco . Everynet, Helium , Kerlink, MachineQ, a Comcast Company, Microsoft , MikroTik , Minol Zenner, Netze BW, Semtech, Senet, STMicroelectronics , TEKTELIC and The Things Industries. In 2018,

390-1124: The Internet in regional, national or global networks, and targets key Internet of things (IoT) requirements, such as bi-directional communication , end-to-end security, mobility and localization services. The low power , low bit rate, and IoT use distinguish this type of network from a wireless WAN that is designed to connect users or businesses, and carry more data, using more power. The LoRaWAN data rate ranges from 0.3 kbit/s to 50 kbit/s per channel. LoRa uses license-free sub-gigahertz radio frequency bands EU868 ( 863–870/873 MHz ) in Europe ; AU915/AS923-1 (915–928 MHz) in South America ; US915 ( 902–928 MHz ) in North America ; IN865 (865–867 MHz) in India ; and AS923 (915–928 MHz) in Asia ; LoRa enables long-range transmissions with low power consumption. The technology covers

420-511: The LoRa Alliance had over 100 LoRaWAN network operators in over 100 countries; in 2023, there are nearly 200, providing coverage in nearly every country in the world. On October 1, 2024, Cisco announced it is "exiting the LoRaWAN space" with no planned migration for Cisco LoRaWAN gateways. Wide Area Network Too Many Requests If you report this error to the Wikimedia System Administrators, please include

450-526: The LoRa Development Portal, the range provided by LoRa can be up to 3 miles (4.8 km) in urban areas, and up to 10 miles (16 km) or more in rural areas (line of sight). In addition, LoRa uses forward error correction coding to improve resilience against interference. LoRa's high range is characterized by high wireless link budgets of around 155 dB to 170 dB. Range extenders for LoRa are called LoRaX. Since LoRa defines

480-429: The communication protocol and system architecture for the network, while LoRa's physical layer enables the long-range communication link. LoRaWAN is also responsible for managing the communication frequencies, data rate , and power for all devices. Devices in the network are asynchronous and transmit when they have data available to send. Data transmitted by an end-node device is received by multiple gateways, which forward

510-538: The cyclic shifted chirp (the instantaneous frequency is linearly increased and wrapped to f 0 − B / 2 {\displaystyle f_{0}-B/2} when it reaches the maximum frequency f 0 + B / 2 {\displaystyle f_{0}+B/2} ). The symbol rate is determined by R s = B / 2 S F {\displaystyle R_{s}=B/2^{\mathrm {SF} }} . LoRa can trade off data rate for sensitivity (assuming

540-493: The data packets to a centralized network server. Data is then forwarded to application servers. This technology shows high reliability for the moderate load, however, it has some performance issues with sending acknowledgements. In the wireless communication, particularly across the IoT applications, collision avoidance is essential for reliable communication and overall spectral efficiency. Previously, LoRaWAN has relied upon ALOHA as

570-481: The details below. Request from 172.68.168.150 via cp1114 cp1114, Varnish XID 935596381 Upstream caches: cp1114 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 08:39:43 GMT Link budget A link budget is an accounting of all of the power gains and losses that a communication signal experiences in a telecommunication system; from a transmitter, through a communication medium such as radio waves , cable , waveguide , or optical fiber , to

600-737: The development of ultra-transparent glass fibers. A typical path loss for single-mode fiber is 0.2 dB/km, far lower than any other guided medium. Link budgets are important in Earth–Moon–Earth communications . As the albedo of the Moon is very low (maximally 12% but usually closer to 7%), and the path loss over the 770,000 kilometre return distance is extreme (around 250 to 310   dB depending on VHF-UHF band used, modulation format and Doppler shift effects), high power (more than 100 watts) and high-gain antennas (more than 20 dB) must be used. The Voyager program spacecraft have

630-408: The first 3 meters. Beyond 3 meters propagation losses indoors can increase at up to 30 dB per 30 meters in dense office environments. This is a good rule-of-thumb, in that it is conservative (it overstates path loss in most cases). Actual propagation losses may vary significantly depending on building construction and layout. The attenuation of the signal is highly dependent on the frequency of

SECTION 20

#1732783183915

660-422: The highest known path loss (308   dB as of 2002 ) and lowest link budgets of any telecommunications circuit. The Deep Space Network has been able to maintain the link at a higher than expected bitrate through a series of improvements, such as increasing the antenna size from 64   m to 70   m for a 1.2   dB gain, and upgrading to low noise electronics for a 0.5   dB gain in 2000–2001. During

690-560: The logarithmic form of the Friis transmission equation . In some cases, it is convenient to consider the loss due to distance and wavelength separately, but in that case, it is important to keep track of which units are being used, as each choice involves a differing constant offset. Some examples are provided below. These alternative forms can be derived by substituting wavelength with the ratio of propagation velocity ( c , approximately 3 × 10  m/s ) divided by frequency, and by inserting

720-399: The loss is proportional to the square of the distance and the square of the frequency. Additionally losses are incurred in most radio links, including atmospheric attenuation by gases, rain, fog and clouds. Fading due to variations of the channel, multipath losses and antenna misalignment. In non line of sight links, diffraction and reflection losses are the most important since the direct path

750-417: The lower, physical, layer, the upper networking layers were lacking. LoRaWAN is a protocol that was developed to define the upper layers of the network. LoRaWAN is a cloud-based medium access control (MAC) layer protocol, but acts mainly as a network layer protocol for managing communication between LPWAN gateways and end-node devices, as a routing protocol maintained by the LoRa Alliance. LoRaWAN defines

780-534: The modem is transmitting for a longer time and consuming more energy. Typical LoRa modems support transmit powers up to +22 dBm. However, the regulations of the respective country may additionally limit the allowed transmit power. Higher transmit power results in higher signal power at the receiver and hence a higher link budget , but at the cost of consuming more energy. There are measurement studies of LoRa performance with regard to energy consumption, communication distances, and medium access efficiency. According to

810-416: The proper conversion factors between km or miles and meters, and between MHz and (1/s). Because of building obstructions such as walls and ceilings, propagation losses indoors can be significantly higher. This occurs because of a combination of attenuation by walls and ceilings, and blockage due to equipment, furniture, and even people. Experience has shown that line-of-sight propagation holds only for about

840-576: The received power, to ensure that the information is received intelligibly with an adequate signal-to-noise ratio . Randomly varying channel gains such as fading are taken into account by adding some margin depending on the anticipated severity of its effects. The amount of margin required can be reduced by the use of mitigating techniques such as antenna diversity or multiple-input and multiple-output (MIMO). A simple link budget equation looks like this: Power levels are expressed in ( dBm ), Power gains and losses are expressed in decibels (dB), which

870-408: The receiver. It is an equation giving the received power from the transmitter power, after the attenuation of the transmitted signal due to propagation, as well as the antenna gains and feedline and other losses, and amplification of the signal in the receiver or any repeaters it passes through. A link budget is a design aid, calculated during the design of a communication system to determine

900-457: The signal. Guided media such as coaxial and twisted pair electrical cable, radio frequency waveguide and optical fiber have losses that are exponential with distance. The path loss will be in terms of dB per unit distance. This means that there is always a crossover distance beyond which the loss in a guided medium will exceed that of a line-of-sight path of the same length. Long distance fiber-optic communication became practical only with

#914085