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Weightless (wireless Communications)
Weightless was a set of low-power wide-area network (LPWAN) wireless technology specifications for exchanging data between a base station and thousands of machines around it. History An event was held at the Moller Centre in Cambridge, UK by Cambridge Wireless on September 30, 2011. Presentations were given by Neul, Landis+Gyr, Cable & Wireless, and ARM Holdings. The technology was promoted by the Weightless Special Interest Group (SIG), announced on December 7, 2012. The group was led by William Webb, a professor at Cambridge and a founder of the company Neul. Another event was held in September 2013, when version 1.0 was published. The name Weightless was chosen to reflect the low overhead per transmission for devices that need to communicate just a few bytes of data. The Weightless logo appears as uppercase letters with the 'W' appearing in the top-right corner of a light blue box that has a solid blue line above it. In September 2014, Cambridge-based Neul was acquired by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-power Wide-area Network
A low-power wide-area network (LPWAN or LPWA network) is a type of wireless telecommunication wide area network designed to allow long-range communications at a low bit rate among things (connected objects), such as sensors operated on a battery. The low power, low bit rate, and intended 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 LPWAN data rate ranges from 0.3 kbit/s to 50 kbit/s per channel. A LPWAN may be used to create a private wireless sensor network, but may also be a service or infrastructure offered by a third party, allowing the owners of sensors to deploy them in the field without investing in gateway technology. Attributes # Long range: The operating range of LPWAN technology varies from a few kilometers in urban areas to over 10 km in rural settings. It can also enable effective data communication in previously infeasible indoor and underground locations. # ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machine To Machine
Machine to machine (M2M) is direct communication between devices using any communications channel, including wired and wireless. Machine to machine communication can include industrial instrumentation, enabling a sensor or meter to communicate the information it records (such as temperature, inventory level, etc.) to application software that can use it (for example, adjusting an industrial process based on temperature or placing orders to replenish inventory). Such communication was originally accomplished by having a remote network of machines relay information back to a central hub for analysis, which would then be rerouted into a system like a personal computer. More recent machine to machine communication has changed into a system of networks that transmits data to personal appliances. The expansion of IP networks around the world has made machine to machine communication quicker and easier while using less power. These networks also allow new business opportunities for consum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mobile Computers
Mobile computing is human–computer interaction in which a computer is expected to be transported during normal usage, which allows for the transmission of data, voice, and video. Mobile computing involves mobile communication, mobile hardware, and mobile software. Communication issues include ad hoc networks and infrastructure networks as well as communication properties, protocols, data formats, and concrete technologies. Hardware includes mobile devices or device components. Mobile software deals with the characteristics and requirements of mobile applications. Main principles * Portability: Devices/nodes connected within the mobile computing system should facilitate mobility. These devices may have limited device capabilities and limited power supply but should have a sufficient processing capability and physical portability to operate in a movable environment. * Connectivity: This defines the quality of service (QoS) of the network connectivity. In a mobile computing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxford University
Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the University of Oxford, the oldest university in the English-speaking world; it has buildings in every style of English architecture since late Anglo-Saxon. Oxford's industries include motor manufacturing, education, publishing, information technology and science. History The history of Oxford in England dates back to its original settlement in the Saxon period. Originally of strategic significance due to its controlling location on the upper reaches of the River Thames at its junction with the River Cherwell, the town grew in national importance during the early Norman period, and in the late 12th century became home to the fledgling University of Oxford. The city was besieged during The Anarchy in 1142. The university rose to domina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DASH7
DASH7 Alliance Protocol (D7A) is an open-source wireless sensor and actuator network protocol, which operates in the 433 MHz, 868 MHz and 915 MHz unlicensed ISM band/SRD band. DASH7 provides multi-year battery life, range of up to 2 km, low latency for connecting with moving things, a very small open-source protocol stack, AES 128-bit shared-key encryption support, and data transfer of up to 167 kbit/s. The DASH7 Alliance Protocol is the name of the technology promoted by the non-profit consortium called the DASH7 Alliance. International standard DASH7 Alliance Protocol originates from the ISO/IEC 18000-7 standard describing a 433 MHz ISM band air interface for active RFID. This standard was mainly used for military logistics. The DASH7 Alliance re-purposed the original 18000-7 technology in 2011 and made it evolve toward a wireless sensor network technology for commercial applications. The DASH7 Alliance Protocol covers all sub-GHz ISM bands, mak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telemetry
Telemetry is the in situ data collection, collection of measurements or other data at remote points and their automatic data transmission, transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek language, Greek roots ''tele'', "remote", and ''metron'', "measure". Systems that need external instructions and data to operate require the counterpart of telemetry, telecommand. Although the term commonly refers to wireless data transfer mechanisms (e.g., using radio, ultrasonic, or Infrared#Communications, infrared systems), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like power line carriers. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive and transmit telemetry data. A ''telemeter'' is a physical device used in telemetry. It consists of a sensor, a transmission path, and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wimax
Worldwide Interoperability for Microwave Access (WiMAX) is a family of wireless broadband communication standards based on the IEEE 802.16 set of standards, which provide physical layer (PHY) and media access control (MAC) options. The WiMAX Forum was formed in June 2001 to promote conformity and interoperability, including the definition of system profiles for commercial vendors. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL". IEEE 802.16m or WirelessMAN-Advanced was a candidate for 4G, in competition with the LTE Advanced standard. WiMAX was initially designed to provide 30 to 40 megabit-per-second data rates, with the 2011 update providing up to 1 Gbit/s for fixed stations. WiMAX release 2.1, popularly branded as WiMAX 2+, is a backwards-compatible transition from previous WiMAX generations. It is compatible and interoperable with TD-LTE. Terminology WiM ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protocol (computing)
A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synchronization of communication and possible error recovery methods. Protocols may be implemented by hardware, software, or a combination of both. Communicating systems use well-defined formats for exchanging various messages. Each message has an exact meaning intended to elicit a response from a range of possible responses pre-determined for that particular situation. The specified behavior is typically independent of how it is to be implemented. Communication protocols have to be agreed upon by the parties involved. To reach an agreement, a protocol may be developed into a technical standard. A programming language describes the same for computations, so there is a close analogy between protocols and programming languages: ''protocols are t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spread Spectrum
In telecommunication and radio communication, spread-spectrum techniques are methods by which a signal (e.g., an electrical, electromagnetic, or acoustic signal) generated with a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth. These techniques are used for a variety of reasons, including the establishment of secure communications, increasing resistance to natural interference, noise, and jamming, to prevent detection, to limit power flux density (e.g., in satellite downlinks), and to enable multiple-access communications. Telecommunications Spread spectrum generally makes use of a sequential noise-like signal structure to spread the normally narrowband information signal over a relatively wideband (radio) band of frequencies. The receiver correlates the received signals to retrieve the original information signal. Originally there were two motivations: either to resist enemy efforts to jam the communications ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
White Spaces (radio)
In telecommunications, white spaces refer to radio frequencies allocated to a broadcasting service but not used locally. National and international bodies assign frequencies for specific uses and, in most cases, license the rights to broadcast over these frequencies. This frequency allocation process creates a bandplan which for technical reasons assigns white space between used radio bands or channels to avoid interference. In this case, while the frequencies are unused, they have been specifically assigned for a purpose, such as a guard band. Most commonly however, these white spaces exist naturally between used channels, since assigning nearby transmissions to immediately adjacent channels will cause destructive interference to both. In addition to white space assigned for technical reasons, there is also unused radio spectrum which has either never been used, or is becoming free as a result of technical changes. In particular, the switchover to digital television frees up ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigfox
Sigfox is a French global network operator founded in 2010 that builds wireless networks to connect low-power objects such as electricity meters and smartwatches, which need to be continuously on and emitting small amounts of data. Sigfox is based in Labège near Toulouse, France, and has over 375 employees. The firm also has offices in Madrid, San Francisco, Sydney and Paris. Technology Sigfox employs the differential binary phase-shift keying (DBPSK) and the Gaussian frequency shift keying (GFSK) that enables communication using the Short-range device band of 868 MHz in Europe, and the Industrial, Scientific and Medical radio band of 902 MHz in the US. It utilizes a wide-reaching signal that passes freely through solid objects, called "Ultra Narrowband" and requires little energy, being termed a "low-power wide-area network" (LPWAN). The network is based on one-hop star topology and requires a mobile operator to carry the generated traffic. The signal can also be us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEEE 802
IEEE 802 is a family of Institute of Electrical and Electronics Engineers (IEEE) standards for local area networks (LAN), personal area network (PAN), and metropolitan area networks (MAN). The IEEE 802 LAN/MAN Standards Committee (LMSC) maintains these standards. The IEEE 802 family of standards has had twenty-four members, numbered 802.1 through 802.24, with a working group of the LMSC devoted to each. However, not all of these working groups are currently active. The IEEE 802 standards are restricted to computer networks carrying variable-size packets, unlike cell relay networks, for example, in which data is transmitted in short, uniformly sized units called cells. Isochronous signal networks, in which data is transmitted as a steady stream of octets, or groups of octets, at regular time intervals, are also outside the scope of the IEEE 802 standards. The number 802 has no significance: it was simply the next number in the sequence that the IEEE used for standards projects. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
