 | This article provides insufficient context for those unfamiliar with the subject.(August 2019) |
IEEE 802.15.4a (formally called IEEE 802.15.4a-2007) was an amendment to IEEE 802.15.4-2006 specifying that additional physical layers (PHYs) be added to the original standard. [1] It has been merged into and is superseded by IEEE 802.15.4-2011. [2]
IEEE 802.15.4-2006 specified four different PHYs, three of which utilized direct-sequence spread spectrum (DSSS), and one which used parallel-sequence spread spectrum (PSSS). [3] IEEE 802.15.4a specifies two additional PHYs using ultra-wideband (UWB) and chirp spread spectrum (CSS). The UWB PHY is designated frequencies in three ranges: below 1 GHz, between 3 and 5 GHz, and between 6 and 10 GHz. The CSS PHY is designated to the 2450 MHz ISM band. [4]
The IEEE 802.15 Low Rate Alternative PHY Task Group (TG4a) for wireless personal area networks (WPANs), as its name implies, was tasked with amending the 802.15 standard to provide alternate PHY standards that would allow for high aggregate throughput (much throughput over time) communications with a precision ranging capability (within 1 meter accuracy) and low power usage within the scope of the WPAN. TG4a was one of two groups tasked to standardize UWB - the other being TG3a. However, TG3a fell apart because of a deadlock between proponents of two competing UWB technologies: Direct Sequence UWB and Multi-Band Orthogonal Frequency Division Multiplexing (OFDM) UWB. Direct Sequence UWB, which was promoted by the Zigbee Alliance, found its home with TG4a, while Multi-Band OFDM UWB was adopted by the WiMedia Alliance which published ECMA-368 (ECMA is another telecommunications standardization body that is similar to the IEEE). [5]
As was mentioned above, the Direct Sequence UWB PHY was the one that ended up being added into the IEEE 802.15.4a standard. Direct Sequence UWB is spectrally efficient, can support precision ranging, and is very robust even at low transmit powers. The Chirp Spread Spectrum PHY was added to the standard because CSS supports communications to devices moving at high speeds and at longer ranges than any of the other PHYs in the IEEE 802.15.4 standard. [4] Basically, both new PHYs added scalability to data rates, longer ranges, and lower power consumption into the standard - thus meeting the intent of the IEEE 802.15 standard to emphasize very low cost communications.
An updated version was in preparation by Task Group 4h . It should correct the errors in the IEEE Standard 802.15.4a-2007 document.
The standard has been consolidated into and superseded by IEEE Standard 802.15.4-2011.
nanotron Technologies developed their first Chirp Spread Spectrum (CSS) smart RF module Smart nanoLOC RF with ranging capabilities certified in Europe and Japan in February 2008. [6]
IMEC made the first UWB transmitter that is compliant to the new standard [7] which they plan to use in wireless autonomous transducer systems used in healthcare, lifestyle and process automation applications. In addition, DecaWave have announced that its 802.15.4a compliant UWB ScenSor chip will be sampled to customers early in 2010. [8]
IEEE 802.15 is a working group of the Institute of Electrical and Electronics Engineers (IEEE) IEEE 802 standards committee which specifies Wireless Specialty Networks (WSN) standards. The working group was formerly known as Working Group for Wireless Personal Area Networks.
IEEE 802.11 is part of the IEEE 802 set of local area network (LAN) technical standards, and specifies the set of medium access control (MAC) and physical layer (PHY) protocols for implementing wireless local area network (WLAN) computer communication. The standard and amendments provide the basis for wireless network products using the Wi-Fi brand and are the world's most widely used wireless computer networking standards. IEEE 802.11 is used in most home and office networks to allow laptops, printers, smartphones, and other devices to communicate with each other and access the Internet without connecting wires. IEEE 802.11 is also a basis for vehicle-based communication networks with IEEE 802.11p.
The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific, and medical (ISM) purposes, excluding applications in telecommunications. Examples of applications for the use of radio frequency (RF) energy in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices are limited to certain bands of frequencies. In general, communications equipment operating in ISM bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation in these bands.
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission used in digital modulation for encoding digital (binary) data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/5G mobile communications.
A personal area network (PAN) is a computer network for interconnecting electronic devices within an individual person's workspace. A PAN provides data transmission among devices such as computers, smartphones, tablets and personal digital assistants. PANs can be used for communication among the personal devices themselves, or for connecting to a higher level network and the Internet where one master device takes up the role as gateway.
In telecommunications, direct-sequence spread spectrum (DSSS) is a spread-spectrum modulation technique primarily used to reduce overall signal interference. The direct-sequence modulation makes the transmitted signal wider in bandwidth than the information bandwidth. After the despreading or removal of the direct-sequence modulation in the receiver, the information bandwidth is restored, while the unintentional and intentional interference is substantially reduced.
Ultra-wideband is a radio technology that can use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum. UWB has traditional applications in non-cooperative radar imaging. Most recent applications target sensor data collection, precise locating, and tracking. UWB support started to appear in high-end smartphones in 2019.
Zigbee is an IEEE 802.15.4-based specification for a suite of high-level communication protocols used to create personal area networks with small, low-power digital radios, such as for home automation, medical device data collection, and other low-power low-bandwidth needs, designed for small scale projects which need wireless connection. Hence, Zigbee is a low-power, low data rate, and close proximity wireless ad hoc network.
IEEE 802.15.4 is a technical standard which defines the operation of a low-rate wireless personal area network (LR-WPAN). It specifies the physical layer and media access control for LR-WPANs, and is maintained by the IEEE 802.15 working group, which defined the standard in 2003. It is the basis for the Zigbee, ISA100.11a, WirelessHART, MiWi, 6LoWPAN, Thread, Matter and SNAP specifications, each of which further extends the standard by developing the upper layers which are not defined in IEEE 802.15.4. In particular, 6LoWPAN defines a binding for the IPv6 version of the Internet Protocol (IP) over WPANs, and is itself used by upper layers like Thread.
The WiMedia Alliance was a non-profit industry trade group that promoted the adoption, regulation, standardization and multi-vendor interoperability of ultra-wideband (UWB) technologies. It existed from about 2002 through 2009.
The UWB Forum was an industry organization promoting interoperable ultra-wideband (UWB) wireless computer networking products from multiple vendors. It was founded in 2004 and disbanded around 2006.
A wide variety of different wireless data technologies exist, some in direct competition with one another, others designed for specific applications. Wireless technologies can be evaluated by a variety of different metrics of which some are described in this entry.
Time of arrival is the absolute time instant when a radio signal emanating from a transmitter reaches a remote receiver. The time span elapsed since the time of transmission is the time of flight . Time difference of arrival (TDOA) is the difference between TOAs.
IEEE 802.11b-1999 or 802.11b is an amendment to the IEEE 802.11 wireless networking specification that extends throughout up to 11 Mbit/s using the same 2.4 GHz band. A related amendment was incorporated into the IEEE 802.11-2007 standard.
In digital communications, chirp spread spectrum (CSS) is a spread spectrum technique that uses wideband linear frequency modulated chirp pulses to encode information. A chirp is a sinusoidal signal whose frequency increases or decreases over time.
MiWi is a proprietary wireless protocol supporting peer-to-peer, star network connectivity. It was designed by Microchip Technology. MiWi uses small, low-power digital radios based on the IEEE 802.15.4 standard, and is designed for low-power, cost-constrained networks, such as industrial monitoring and control, home and building automation, remote control, wireless sensors, lighting control, and automated meter reading.
IEEE 802.11ah is a wireless networking protocol published in 2017 called Wi-Fi HaLow as an amendment of the IEEE 802.11-2007 wireless networking standard. It uses 900 MHz license-exempt bands to provide extended-range Wi-Fi networks, compared to conventional Wi-Fi networks operating in the 2.4 GHz and 5 GHz bands. It also benefits from lower energy consumption, allowing the creation of large groups of stations or sensors that cooperate to share signals, supporting the concept of the Internet of things (IoT). The protocol's low power consumption competes with Bluetooth, LoRa, and Zigbee, and has the added benefit of higher data rates and wider coverage range.
This needs to include cellular LPWAN technologies such as NB-IoT, LTE-M, Cat-M1
In communication engineering, Ultra NarrowBand (UNB) systems are those in which the channel has a very narrow bandwidth.
Ultra-wideband impulse radio ranging is a wireless positioning technology based on IEEE 802.15.4z standard, which is a wireless communication protocol introduced by IEEE, for systems operating in unlicensed spectrum, equipped with extremely large bandwidth transceivers. UWB enables very accurate ranging without introducing significant interference with narrowband systems. To achieve these stringent requirements, UWB-IR systems exploit the available bandwidth that they support, which guarantees very accurate timing and robustness against multipath, especially in indoor environments. The available bandwidth also enables UWB systems to spread the signal power over a large spectrum, avoiding narrowband interference.
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