ANT (network)
Encyclopedia
ANT is a proprietary
wireless sensor network
technology featuring a wireless communications protocol stack
that enables semiconductor
radios operating in the 2.4 GHz
Industrial, Scientific and Medical allocation of the RF
spectrum ("ISM band
") to communicate by establishing standard rules for co-existence, data representation, signalling, authentication
and error detection.
The ANT protocol is designed and marketed by Dynastream Innovations Inc., a Cochrane
, Canada
based company, which in turn is a wholly owned subsidiary of GPS equipment manufacturer Garmin
.
The ANT protocol is ported to a limited set of low-power RF transceiver
chips from specialist manufacturers, such as Nordic Semiconductor
(since 2005) and Texas Instruments
(since 2010). A typical ANT protocol transceiver is a black box
that comes pre-loaded with the protocol software and must be controlled by an application processor via a UART, SPI
or USB interface.
ANT is characterized by a low computational overhead
, and high efficiency
resulting in low power
consumption by the radios supporting the protocol.
. These applications are often constrained by strict power, footprint and cost requirements. Typical applications measure parameter
s that don't change rapidly (for example, temperature
or humidity
) so updates every few seconds are satisfactory.
Commercial wireless sensor networks must be reliable, feature low power consumption (to extend battery life and minimize maintenance), and be low cost to purchase, install and maintain. In addition, transceivers in close proximity need to co-exist in harmony by being able to transmit and receive without interference
from their neighbors and other wireless devices operating in the 2.4 GHz band.
ANT-powered nodes
are claimed to be capable of acting as slaves or masters within a wireless sensor network. This means the nodes can act as transmitters, receivers or transceivers to route traffic to other nodes. In addition, every node is capable of determining when to transmit based on the activity of its neighbors.
belts, watches, cycle power and cadence
meters, and distance
and speed
monitors to form wireless Personal Area Network
s (PANs) monitoring a user's performance.
Manufacturers such as Garmin
, Nike, Suunto
and Tacx have used ANT technology in their performance monitoring products.
Recently, ANT (the company) has attempted to diversify, claiming ANT wireless sensor networking technology's low overhead, low power, interference free characteristics and operation in the 2.4 GHz ISM band suit applications the health, home automation
and industrial sectors.
) during reception and 13.5mA (at -5dB) during transmission) and return to sleep mode.
Each ANT channel consists of one or more transmitting nodes and one or more receiving nodes depending on the network topology. Any node can transmit or receive so the channels are bi-directional.
ANT accommodates three types of messaging: broadcast, acknowledged and burst. Broadcast is a one-way communication from one node to another. The receiving node transmits no acknowledgment. This technique is suited to sensor
applications and is the most economical method of operation.
Acknowledged messaging confirms receipt of data packets. The transmitter is informed of success or failure, although there are no retransmissions. This technique is suited to control applications.
ANT can also be used for burst messaging; this is a multi-message transmission technique using the full data bandwidth and running to completion. The receiving node acknowledges receipt and informs of corrupted packets that the transmitter then resends. The packets are sequence numbered for traceability. This technique is suited to data block transfer where the integrity of the data is paramount.
protocol, prior to v4.0, were designed for rapid file transfer between devices in a PAN such as a PDA
, cell-phone and portable computer; focusing on applications with lower bandwidth requirements than that offered by WiFi
. Previous versions of Bluetooth were not designed for large wireless sensor networks, but were capable of forming star networks of up to eight devices (one master and seven slaves).
Bluetooth low energy
is the new protocol released for low power wireless embedded devices that can operate on a single coil-cell battery from months to years, such as Wireless Sensor Network
, watches, and sports equipment. Currently, Bluetooth low energy (BLE) only supports star-bus network topology which limits applications to a single hop communication range between 50 m to 100 m (330 ft). BLE is the hallmark feature of Bluetooth 4.0, a dual-mode core chip supporting BT v3.0 and BLE, which will give BLE a "free-ride" into the mass market of smart-phones, laptops, tablets, etc. This "free-ride" will also allow BLE to compete against other short range technologies, perhaps unfairly, such as NFC
. While BLE cannot currently compete with ANT, Zigbee, or WirelessHART in applications requiring a large multi-hop coverage area, BLE can definitely compete in short-range single-hop applications. BLE is expected to debut in devices on the market late 2011. BLE silicon chips are already in mass market and provided by companies such as Nordic Semiconductor
, Texas Instruments
, CSR
, Taiyo Yuden
, Epson, and many more.
A more direct comparison can be drawn with ZigBee
. ZigBee is based on the IEEE 802.15.4
standard PHY and Media Access Control (MAC) layers, and supports the ZigBee Alliance's own Network (NWK) and Application (APL) layers (refer to the OSI model
). ZigBee's IEEE 802.15.4 PHY for the 2.4 GHz frequency band has a raw data rate of 250 kbit/s, compared to ANT's 1 Mbit/s, requiring ZigBee to stay on air longer than ANT to transmit a given volume of data.
ANT transceivers using coin cell-type batteries is claimed to operate up to three years in low use applications.
and some cordless phones all use the 2.4 GHz band (as well as 868- and 915 MHz for regional variants in the latter's case), along with proprietary forms of wireless Ethernet and USB
.
Wi-Fi/ZigBee and Bluetooth employ Direct Sequence Spread Spectrum (DSSS) and Frequency-Hopping Spread Spectrum
(FHSS) schemes respectively to maintain the integrity
of the wireless link.
ANT uses an adaptive isochronous
network technology to ensure co-existence. This scheme provides the ability for each transmission to occur in an interference free time slot within the defined frequency band. The radio transmits for less than 150 µs per message, allowing a single channel to be divided into hundreds of timeslots. The ANT messaging period (the time between each node transmitting its data) determines how many time slots are available.
ANT's adaptive isochronous scheme doesn't require a master clock. Transmitters start broadcasting at regular intervals but then modify the transmission timing if interference from a neighbor is detected on a particular timeslot. This flexibility allows ANT to adapt to hostile conditions but ensures there is no overhead when interference is not present.
If the radio environment is very crowded, ANT can use frequency agility to allow an application microcontroller
-controlled "hop" to an alternative 1 MHz channel in the 2.4 GHz band which can then be subdivided into timeslots.
Proprietary protocol
In telecommunications, a proprietary protocol is a communications protocol owned by a single organization or individual.-Enforcement:Proprietors may enforce restrictions through patents and by keeping the protocol specification a trade secret...
wireless sensor network
Wireless sensor network
A wireless sensor network consists of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants and to cooperatively pass their data through the network to a main location. The more modern...
technology featuring a wireless communications protocol stack
Protocol stack
The protocol stack is an implementation of a computer networking protocol suite. The terms are often used interchangeably. Strictly speaking, the suite is the definition of the protocols, and the stack is the software implementation of them....
that enables semiconductor
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...
radios operating in the 2.4 GHz
GHZ
GHZ or GHz may refer to:# Gigahertz .# Greenberger-Horne-Zeilinger state — a quantum entanglement of three particles.# Galactic Habitable Zone — the region of a galaxy that is favorable to the formation of life....
Industrial, Scientific and Medical allocation of the RF
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
spectrum ("ISM band
ISM band
The industrial, scientific and medical radio bands are radio bands reserved internationally for the use of radio frequency energy for industrial, scientific and medical purposes other than communications....
") to communicate by establishing standard rules for co-existence, data representation, signalling, authentication
Authentication
Authentication is the act of confirming the truth of an attribute of a datum or entity...
and error detection.
The ANT protocol is designed and marketed by Dynastream Innovations Inc., a Cochrane
Cochrane, Alberta
Cochrane is a town in the Canadian province of Alberta. The town is located 18 km west of the Calgary city limits along Highway 1A. With a population of 15,424 , Cochrane is the second largest town in Alberta and one of the fastest growing communities in Canada...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
based company, which in turn is a wholly owned subsidiary of GPS equipment manufacturer Garmin
Garmin
Garmin Ltd. , incorporated in Schaffhausen, Switzerland, is the parent company of a group of companies founded in 1989 by Gary Burrell and Min Kao , that develops consumer, aviation, and marine technologies for the Global Positioning System...
.
The ANT protocol is ported to a limited set of low-power RF transceiver
Transceiver
A transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver. The term originated in the early 1920s...
chips from specialist manufacturers, such as Nordic Semiconductor
Nordic Semiconductor
Nordic Semiconductor is a fabless semiconductor company, developing and manufacturing integrated circuits. The company specializes in wireless communication, mixed signal as well as complex digital and analogue integrated circuit design. High speed wireless communication in the 2.4 GHz ISM band,...
(since 2005) and Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
(since 2010). A typical ANT protocol transceiver is a black box
Black box
A black box is a device, object, or system whose inner workings are unknown; only the input, transfer, and output are known characteristics.The term black box can also refer to:-In science and technology:*Black box theory, a philosophical theory...
that comes pre-loaded with the protocol software and must be controlled by an application processor via a UART, SPI
SPI
SPI may refer to:-Companies:* Shotmed Paper Industries, an Egyptian paper manufacturer* Simulations Publications, Inc., an American publisher of board wargames* Sony Pictures Imageworks, a visual effects and animation company...
or USB interface.
ANT is characterized by a low computational overhead
Computational overhead
In computer science, overhead is generally considered any combination of excess or indirect computation time, memory, bandwidth, or other resources that are required to attain a particular goal...
, and high efficiency
Energy conversion efficiency
Energy conversion efficiency is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The useful output may be electric power, mechanical work, or heat.-Overview:...
resulting in low power
Power (physics)
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
consumption by the radios supporting the protocol.
Overview
The applications for which ANT is targeted are characterized by periodic transfer of small amounts of sensor information between several, scores or hundreds of interconnected devices in point-to-point, star, tree or mesh network topologiesNetwork topology
Network topology is the layout pattern of interconnections of the various elements of a computer or biological network....
. These applications are often constrained by strict power, footprint and cost requirements. Typical applications measure parameter
Parameter
Parameter from Ancient Greek παρά also “para” meaning “beside, subsidiary” and μέτρον also “metron” meaning “measure”, can be interpreted in mathematics, logic, linguistics, environmental science and other disciplines....
s that don't change rapidly (for example, temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
or humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
) so updates every few seconds are satisfactory.
Commercial wireless sensor networks must be reliable, feature low power consumption (to extend battery life and minimize maintenance), and be low cost to purchase, install and maintain. In addition, transceivers in close proximity need to co-exist in harmony by being able to transmit and receive without interference
Electromagnetic interference
Electromagnetic interference is disturbance that affects an electrical circuit due to either electromagnetic induction or electromagnetic radiation emitted from an external source. The disturbance may interrupt, obstruct, or otherwise degrade or limit the effective performance of the circuit...
from their neighbors and other wireless devices operating in the 2.4 GHz band.
ANT-powered nodes
Node (networking)
In communication networks, a node is a connection point, either a redistribution point or a communication endpoint . The definition of a node depends on the network and protocol layer referred to...
are claimed to be capable of acting as slaves or masters within a wireless sensor network. This means the nodes can act as transmitters, receivers or transceivers to route traffic to other nodes. In addition, every node is capable of determining when to transmit based on the activity of its neighbors.
Typical applications
ANT has been targeted at the sports sector, particularly fitness and cycling performance monitoring. The transceivers are embedded in equipment such as heart rateHeart rate
Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....
belts, watches, cycle power and cadence
Cadence (cycling)
In cycling, cadence is the number of revolutions of the crank per minute; roughly speaking, this is the rate at which a cyclist is pedalling/turning the pedals...
meters, and distance
Distance
Distance is a numerical description of how far apart objects are. In physics or everyday discussion, distance may refer to a physical length, or an estimation based on other criteria . In mathematics, a distance function or metric is a generalization of the concept of physical distance...
and speed
Speed
In kinematics, the speed of an object is the magnitude of its velocity ; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as...
monitors to form wireless Personal Area Network
Personal area network
A personal area network is a computer network used for communication among computer devices, including telephones and personal digital assistants, in proximity to an individual's body. The devices may or may not belong to the person in question. The reach of a PAN is typically a few meters...
s (PANs) monitoring a user's performance.
Manufacturers such as Garmin
Garmin
Garmin Ltd. , incorporated in Schaffhausen, Switzerland, is the parent company of a group of companies founded in 1989 by Gary Burrell and Min Kao , that develops consumer, aviation, and marine technologies for the Global Positioning System...
, Nike, Suunto
Suunto
Suunto Oy, based in Finland, is a company that produces and markets sports precision instruments for Diving, Training and Outdoor sports. Headquartered in Vantaa, Suunto employs more than 500 people worldwide, and its products are sold in over 100 countries...
and Tacx have used ANT technology in their performance monitoring products.
Recently, ANT (the company) has attempted to diversify, claiming ANT wireless sensor networking technology's low overhead, low power, interference free characteristics and operation in the 2.4 GHz ISM band suit applications the health, home automation
Home automation
Home automation is the residential extension of "building automation". It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC , appliances, and other systems, to provide improved convenience, comfort, energy efficiency and...
and industrial sectors.
Technical information
The ANT protocol has an efficiency (determined by the ratio of overhead to data) of 47 percent. ANT can be configured to spend long periods in a low power “sleep” mode (consuming of the order of microamps of current), wake up briefly to communicate (when consumption rises to around 22mA (at -5dBDecibel
The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...
) during reception and 13.5mA (at -5dB) during transmission) and return to sleep mode.
Each ANT channel consists of one or more transmitting nodes and one or more receiving nodes depending on the network topology. Any node can transmit or receive so the channels are bi-directional.
ANT accommodates three types of messaging: broadcast, acknowledged and burst. Broadcast is a one-way communication from one node to another. The receiving node transmits no acknowledgment. This technique is suited to sensor
Sensor
A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...
applications and is the most economical method of operation.
Acknowledged messaging confirms receipt of data packets. The transmitter is informed of success or failure, although there are no retransmissions. This technique is suited to control applications.
ANT can also be used for burst messaging; this is a multi-message transmission technique using the full data bandwidth and running to completion. The receiving node acknowledges receipt and informs of corrupted packets that the transmitter then resends. The packets are sequence numbered for traceability. This technique is suited to data block transfer where the integrity of the data is paramount.
Comparison with Bluetooth, Bluetooth Low Energy, and ZigBee
Previous versions of the BluetoothBluetooth
Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances from fixed and mobile devices, creating personal area networks with high levels of security...
protocol, prior to v4.0, were designed for rapid file transfer between devices in a PAN such as a PDA
Personal digital assistant
A personal digital assistant , also known as a palmtop computer, or personal data assistant, is a mobile device that functions as a personal information manager. Current PDAs often have the ability to connect to the Internet...
, cell-phone and portable computer; focusing on applications with lower bandwidth requirements than that offered by WiFi
WIFI
WIFI is a radio station broadcasting a brokered format. Licensed to Florence, New Jersey, USA, the station is currently operated by Florence Broadcasting Partners, LLC.This station was previously owned by Real Life Broadcasting...
. Previous versions of Bluetooth were not designed for large wireless sensor networks, but were capable of forming star networks of up to eight devices (one master and seven slaves).
Bluetooth low energy
Bluetooth low energy
Bluetooth low energy is a feature of Bluetooth 4.0 wireless radio technology, aimed at new, principally low-power and low-latency, applications for wireless devices within a short range...
is the new protocol released for low power wireless embedded devices that can operate on a single coil-cell battery from months to years, such as Wireless Sensor Network
Wireless sensor network
A wireless sensor network consists of spatially distributed autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, motion or pollutants and to cooperatively pass their data through the network to a main location. The more modern...
, watches, and sports equipment. Currently, Bluetooth low energy (BLE) only supports star-bus network topology which limits applications to a single hop communication range between 50 m to 100 m (330 ft). BLE is the hallmark feature of Bluetooth 4.0, a dual-mode core chip supporting BT v3.0 and BLE, which will give BLE a "free-ride" into the mass market of smart-phones, laptops, tablets, etc. This "free-ride" will also allow BLE to compete against other short range technologies, perhaps unfairly, such as NFC
NFC
NFC may refer to:* Nagacorp FC, a Cambodian sporting club* National Finance Center, a division of the United States Department of Agriculture* National Football Conference, a constituent conference of the National Football League...
. While BLE cannot currently compete with ANT, Zigbee, or WirelessHART in applications requiring a large multi-hop coverage area, BLE can definitely compete in short-range single-hop applications. BLE is expected to debut in devices on the market late 2011. BLE silicon chips are already in mass market and provided by companies such as Nordic Semiconductor
Nordic Semiconductor
Nordic Semiconductor is a fabless semiconductor company, developing and manufacturing integrated circuits. The company specializes in wireless communication, mixed signal as well as complex digital and analogue integrated circuit design. High speed wireless communication in the 2.4 GHz ISM band,...
, Texas Instruments
Texas Instruments
Texas Instruments Inc. , widely known as TI, is an American company based in Dallas, Texas, United States, which develops and commercializes semiconductor and computer technology...
, CSR
CSR
CSR may refer to:In business:* CSR Limited, an Australian industrial company, formerly known as Colonial Sugar Refining Company* CSR plc, or Cambridge Silicon Radio, a British silicon chip designer and software company...
, Taiyo Yuden
Taiyo Yuden
is a Japanese materials and electronics company, situated in Ueno, Taito, Tokyo, that helped pioneer recordable CD technology along with Sony and Philips in 1988. Founded 60 years ago, Taiyo Yuden currently operates factories in Japan, Singapore, Korea, China, the Philippines, Taiwan, Malaysia,...
, Epson, and many more.
A more direct comparison can be drawn with ZigBee
ZigBee
ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on an IEEE 802 standard for personal area networks. Applications include wireless light switches, electrical meters with in-home-displays, and other consumer and industrial...
. ZigBee is based on the IEEE 802.15.4
IEEE 802.15.4
IEEE 802.15.4 is a standard which specifies the physical layer and media access control for low-rate wireless personal area networks . It is maintained by the IEEE 802.15 working group....
standard PHY and Media Access Control (MAC) layers, and supports the ZigBee Alliance's own Network (NWK) and Application (APL) layers (refer to the OSI model
OSI model
The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
). ZigBee's IEEE 802.15.4 PHY for the 2.4 GHz frequency band has a raw data rate of 250 kbit/s, compared to ANT's 1 Mbit/s, requiring ZigBee to stay on air longer than ANT to transmit a given volume of data.
ANT transceivers using coin cell-type batteries is claimed to operate up to three years in low use applications.
Interference immunity
ANT, ZigBee, Bluetooth, Wi-FiWi-Fi
Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
and some cordless phones all use the 2.4 GHz band (as well as 868- and 915 MHz for regional variants in the latter's case), along with proprietary forms of wireless Ethernet and USB
Wireless USB
Wireless USB is a short-range, high-bandwidth wireless radio communication protocol created by the . Wireless USB is sometimes abbreviated as "WUSB", although the USB Implementers Forum discourages this practice and instead prefers to call the technology "Certified Wireless USB" to distinguish it...
.
Wi-Fi/ZigBee and Bluetooth employ Direct Sequence Spread Spectrum (DSSS) and Frequency-Hopping Spread Spectrum
Frequency-hopping spread spectrum
Frequency-hopping spread spectrum is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver...
(FHSS) schemes respectively to maintain the integrity
Data integrity
Data Integrity in its broadest meaning refers to the trustworthiness of system resources over their entire life cycle. In more analytic terms, it is "the representational faithfulness of information to the true state of the object that the information represents, where representational faithfulness...
of the wireless link.
ANT uses an adaptive isochronous
Isochronous
Isochronous : From Greek iso, equal + chronos, time. It literally means regularly, or at equal time intervals. In general English language, it refers to something that occurs at a regular interval, of the same duration; as opposed to synchronous which refers to more than one thing happening at the...
network technology to ensure co-existence. This scheme provides the ability for each transmission to occur in an interference free time slot within the defined frequency band. The radio transmits for less than 150 µs per message, allowing a single channel to be divided into hundreds of timeslots. The ANT messaging period (the time between each node transmitting its data) determines how many time slots are available.
ANT's adaptive isochronous scheme doesn't require a master clock. Transmitters start broadcasting at regular intervals but then modify the transmission timing if interference from a neighbor is detected on a particular timeslot. This flexibility allows ANT to adapt to hostile conditions but ensures there is no overhead when interference is not present.
If the radio environment is very crowded, ANT can use frequency agility to allow an application microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
-controlled "hop" to an alternative 1 MHz channel in the 2.4 GHz band which can then be subdivided into timeslots.