===== IEEE802.15.4a standard - ScenSor - DecaWave

IEEE802.15.4-2011 Standard

Standard-based vs Proprietary Technology

Standard-based technology offers significant advantages and safeguards which proprietary systems cannot match. Standardisation means a technology has the support of its industry – it ensures interoperability and future proofing, and thereby contributes greatly to customer confidence. Additionally, as it draws on research from multiple sources, standardisation means technologies are continually improving in their performance, and expanding into new areas and applications. Thus standardisation allows for larger and homogenous markets.

The UWB PHY implemented by the DW1000 follows the UWB PHY standard defined by the IEEE 802.15.4a-2007 amendment that added UWB and CSS PHYs to the IEEE 802.15.4 (2006) standard. This 2006 standard and its ratified amendments including "4a" were "rolled-up" together in 2011 to make the IEEE 802.15.4-2011 version of the standard.

IEEE802.15.4-2011 Standard

The Institute of Electrical and Electronics Engineers Standards Association (IEEE-SA) is a leading developer of global industry standards in a broad-range of industries, including: Power and Energy, Biomedical and Healthcare, Information Technology, Telecommunications, Transportation, Nanotechnology and Information Assurance.

IEEE802 refers to a family of IEEE standards dealing with local and metropolitan area networks including the IEEE802.11 standard with which most of us are familiar under its more common name; WiFi. The IEEE802.15.4 standard was designed to deal with relatively short range Wireless Personal Area Networks (WPAN) and includes the PHY and MAC specification for Zigbee devices.

The 802.15.4a amendment to this standard was ratified in 2007 and added two additional physical interface (PHY) standards to the original IEEE802.15.4 standard. One of these additional interface standards is based on Ultra Wideband.  In 2011, the 'a' amendment was incorporated into the main body of the standard and was denoted IEEE802.15.4-2011. IEEE802.15.4-2011 adds significantly to the IEEE802.15.4 standard,

The portion of the IEEE802.15.4 standard that relates to IR-UWB specifies 4 different data rates; 110 kbps, 850 kbps, 6.8 Mbps and 27 Mbps, over 15 different frequency bands at least some of which have now been authorised by regulatory bodies in most of the main geographies worldwide. The standard also includes specific support for ranging.

Many of ScenSor’s high performing features derive from our conformance with IEEE802.15.4-2011.  High precision ranging / location capability, high aggregate data throughput, multi-path immunity and operation in interference-free parts of the spectrum all derive from adherence to IEEE802.15.4-2011. 

In addition to all that, at DecaWave, we have made a number of key innovations in our implementation of the IEEE802.15.4-2011 standard.

The first is in using a coherent receiver. This is a specific technique that, simply put, allows more energy to be extracted from the received signal than would be the case in a non-coherent implementation. This increases the operating range in non-line-of-sight conditions which is key to operation at a distance indoors where there are likely to be many obstacles and a line of sight between the transmitter and receiver most likely will not exist.

The second is proprietary to DecaWave and is the subject of patent applications. This allows us to implement the design in a significantly smaller silicon area than would otherwise be the case. Generally speaking in semiconductor manufacture cost is proportional to die size so the smaller the die the lower the cost – and our novel implementation allows ScenSor to be the smallest UWB IEEE802.15.4-2011 compliant chip on the market.