IEEE 802.15.4a
Encyclopedia
IEEE 802.15.4a is an amendment to IEEE 802.15.4
(formally called IEEE 802.15.4-2006) specifying that additional physical layers (PHYs) be added to the original standard.
(DSSS), and one which used parallel-sequence spread spectrum (PSSS). 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
.
personal area network
s (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 (lots of 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).
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. 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 is in preparation by Task Group 4h https://mentor.ieee.org/802.15/documents?is_group=004h. It should correct the errors in the IEEE Standard 802.15.4a-2007 document.
IMEC made the first UWB transmitter that is compliant to the new standard 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.
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....
(formally called IEEE 802.15.4-2006) specifying that additional physical layers (PHYs) be added to the original standard.
Overview
IEEE 802.15.4-2006 specified four different PHYs, three of which utilized direct-sequence spread spectrumDirect-sequence spread spectrum
In telecommunications, direct-sequence spread spectrum is a modulation technique. As with other spread spectrum technologies, the transmitted signal takes up more bandwidth than the information signal that is being modulated. The name 'spread spectrum' comes from the fact that the carrier signals...
(DSSS), and one which used parallel-sequence spread spectrum (PSSS). IEEE 802.15.4a specifies two additional PHYs using ultra-wideband
Ultra-wideband
Ultra-wideband is a radio technology that can be used at very low energy levels for short-range high-bandwidth communications by using a large portion of the radio spectrum. UWB has traditional applications in non-cooperative radar imaging...
(UWB) and chirp spread spectrum
Chirp spread spectrum
In digital communications, Chirp spread spectrum 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 a certain amount of time...
(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
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....
.
History
The IEEE 802.15 Low Rate Alternative PHY Task Group (TG4a) for wirelessWireless
Wireless telecommunications is the transfer of information between two or more points that are not physically connected. Distances can be short, such as a few meters for television remote control, or as far as thousands or even millions of kilometers for deep-space radio communications...
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 (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 (lots of 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
WiMedia Alliance
The WiMedia Alliance is a non-profit open industry association that promotes and enables the rapid adoption, regulation, standardization and multi-vendor interoperability of ultra-wideband worldwide....
which published ECMA-368 (ECMA is another telecommunications standardization body that is similar to the IEEE).
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. 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 is in preparation by Task Group 4h https://mentor.ieee.org/802.15/documents?is_group=004h. It should correct the errors in the IEEE Standard 802.15.4a-2007 document.
Uses
Nanotron techniques developed their first Chirp Spread Spectrum (CSS) smart RF module Smart nanoLOC RF with ranging capabilities certified in Europe and Japan in February 2008.IMEC made the first UWB transmitter that is compliant to the new standard 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.
See also
- ZigBeeZigBeeZigBee 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...
- Ultra-widebandUltra-widebandUltra-wideband is a radio technology that can be used at very low energy levels for short-range high-bandwidth communications by using a large portion of the radio spectrum. UWB has traditional applications in non-cooperative radar imaging...
- DASH7DASH7DASH7 is an open source wireless sensor networking standard for wireless sensor networking, which operates in the 433 MHz unlicensed ISM 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...
- IEEE 802.11IEEE 802.11IEEE 802.11 is a set of standards for implementing wireless local area network computer communication in the 2.4, 3.6 and 5 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee . The base version of the standard IEEE 802.11-2007 has had subsequent...
- IEEE 802.15.4IEEE 802.15.4IEEE 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....
- IEEE 802.16IEEE 802.16IEEE 802.16 is a series of Wireless Broadband standards authored by the Institute of Electrical and Electronics Engineers . The IEEE Standards Board in established a working group in 1999 to develop standards for broadband Wireless Metropolitan Area Networks...
- IEEE 802.20IEEE 802.20IEEE 802.20 or Mobile Broadband Wireless Access was a specification by the standard association of the Institute of Electrical and Electronics Engineers for mobile wireless Internet access networks...
- IEEE 802.22IEEE 802.22IEEE 802.22 is a standard for Wireless Regional Area Network using white spaces in the TV frequency spectrum. The development of the IEEE 802.22 WRAN standard is aimed at using cognitive radio techniques to allow sharing of geographically unused spectrum allocated to the Television Broadcast...
External links
- Download the 802.15 standards from IEEE
- IEEE 802.15 WPAN Low Rate Alternative PHY Task Group 4a (TG4a)
- about coexistence of IEEE 802.15.4aCSS with IEEE 802.11b/g (2.45GHz WLAN)
- IEEE 802.15.4a-2007 Update and Corrections / Task Group 4h (TG4h)
- SAYME Wireless Sensor Network - Wireless Sensor Network Platform for energy efficiency improvement and intelligent remote control applications.