Around 2001, the Nokia Research Center was looking at options for future personal wireless networking. The company realized that there was room for developing an ultra-low power, wireless technology that could interface cost-effectively with a large variety of existing and future devices, which, until now had not been effectively served by available existing technologies. Towards this end, Nokia decided to create a new open wireless protocol, and now, along with its partners Broadcom Corporation, CSR, Epson, and Nordic Semiconductor, is working to bring it to market.
While the Wibree protocol is currently under development and should be ready by mid 2007, the availability of the Wibree chip depends upon the semiconductor manufacturers’ schedules. Wibree is similar in many respects to the now prevalent Bluetooth standard. Both use the 2.45 GHz band to transfer data and have a 1 Mbps transfer rate (although the newer Bluetooth 2.0 standard already incorporates a 3.0 Mbps transfer rate) and a rage of about 10 meters (m). The two complementary technologies differ in size, price, and most of all power consumption. Wibree would use only a fraction of the power consumed by today’s Bluetooth chips, resulting in a much longer battery life and more compact devices. While Bluetooth can be used to transmit audio and media files, Wibree is designed to extend this network by serving applications that transmit only small amounts of data and where size and cost are priorities. Many applications that were not cost-effective using existing Bluetooth technology, such as wirelessly controlled toys, watches, medical and sports sensors, and a range of other applications that have not been conceived yet, might be developed using Wibree technology.
There will be two types of Wibree implementations – one based on the Wibree stand-alone chip, and another based on the Wibree-Bluetooth dual-mode chip – which will serve different purposes and be installed on different devices. Stand-alone Wibree chips would be implemented in small, low cost devices such as wireless mouse and keyboards, sensors, and toys. The Wibree-Bluetooth dual-mode chips would probably be implemented in future mobile phones, allowing users to benefit from both worlds – Bluetooth 2.0 high speed and Wibree’s low power and extended ability to communicate with a new generation of smaller wireless devices.
The Wireless Zoo
Apart from the well known Bluetooth format, which operates at a distance of up to ten m (and the less common Bluetooth Class 1, which can broadcast up to 100 m) and can transmit up to 3.0 Mb/s, there are currently a host of other wireless technologies on the market and even more planned for the next few years. The following is a list of some of the main technologies:
Wi-Fi – Initially conceived in the 1990’s, this wireless protocol was developed for wireless local area networks (LANs) and is used to connect computers, mobile phones, VoIP (Voice over Internet Protocol) phones, game consoles, and even TVs and cameras. The protocol has evolved in recent years and now includes several standards (IEEE 802.11a, 802.11b, 802.11g, as well as the upcoming 802.11n). The transfer rate of Wi-Fi has always been considerable – 802.11b, ratified in 1999, reached a maximum data transfer rate of 11 Mb/s; 802.11g, ratified in 2003, reached a maximum data transfer rate of 54 Mb/s; and the future 802.11n might reach a maximum data transfer rate of 540 Mb/s. The range of Wi-Fi is also considerable and canexceed 100 m in some outdoor conditions. One of the main problems with Wi-Fi is its high power consumption, which is the result of the relatively long range and high data transfer rate of the technology. Wi-Fi is also relatively expensive and has higher latency than some of the other wireless technologies.
WiMax – In 2001, work on IEEE 802.16 began. This new standard was meant to create metropolitan wireless networks to accommodate or replace the Wi-Fi’s local networks. The WiMax protocol allows for high speed (up to around 70 Mb/s) and long range (several and in some cases several dozen of kilometers) wireless communication. WiMax could potentially allow cheap, high speed wireless communication everywhere and find uses ranging from VoIP mobile phones to high definition wireless TV broadcasting. Like Wi-Fi, the power consumption of WiMax is considerable, and therefore is not suitable for use in small, low power devices.
Wireless USB – Wireless USBorWUSBis a new short-range, high speed wireless extension to the USB standard that combines the speed and security of wired technology with the ease-of-use of wireless technology. WUSB is based on ultra-wideband (UWB) wireless technology, capable of sending up to 480 Mb/s at distances of up to 3 m, and 110 Mb/s at up to 10 m. WUSB is intended to compete directly with Bluetooth and find applications in game controllers, printers, scanners, digital cameras, MP3 players, hard drives, flash drives, and even TVs and other video-capable devices. The WUSB technology has suffered some setbacks due to both technical issues and disputes between some of the major players involved in its development.
Radio Frequency Identification – Modern Radio Frequency Identification technology (also known as RFID) was first demonstrated by researchers from Los Alamos, California in 1973. The most familiar form of RFID is the RFID tag, consisting of passive, semi-passive, and active RFID chips. Passive RFID chips use the minute electrical current induced in their antennas by incoming radio frequency signals to provide them with just enough power to operate and transmit data in response. Semi-active and active RFID tags include a battery, which helps them to stay on, respond more quickly, and transmit their information more effectively; the trade-off is that when the battery drains, it must be replaced. While passive RFID tags have a typical range of a few meters, active RFID tags can reach dozens or even hundreds of meters. These ranges make them perfect for monitoring product tracking, transport payments, wireless sensors, and various other applications. The main advantage of RFID devices is their very low power consumption (a passive RFID device doesn’t even require a battery), but they are unable to store large amounts of information and have a very low data transfer rate (usually measured in Kb/s rather then Mb/s). Recently, HP revealed a new type of wireless technology called Memory Spot that consumes very little energy and does not require a battery. This upcoming technology has a 10 Mb/s transfer rate, but is designed to work only at a very close range (around 1 mm), making it suitable only for a number of applications.
ZigBee – ZigBee is the name of an alliance of companies formed around a standard approved in 2003 called 802.15.4. The ZigBee protocol promises to provide a long battery life (months or even years on a single battery charge) and to be a lower-cost alternative to Bluetooth for wireless sensing and control applications. The ZigBee alliance consists of a group of companies that includes Invensys, Honeywell, Mitsubishi Electric, Motorola, and Philips, to name a few. Its name comes from the zig-zag flight path of bees, forming mesh networks between flowers. Members of the ZigBee alliance believe that mesh networking is the key to unattended wireless systems for smart homes as well as wirelessly-controlled sensors for medical uses and industry. ZigBee also displays very low latency (much lower than Bluetooth, for example), which is critical for certain applications such as heart sensors.
Since Nokia views Wibree as a technology complementary to Bluetooth, its closest competition might be ZigBee. Both technologies offer extended battery life in exchange for a relatively low data transfer rate (1 Mb/s for Wibree and 0.25 Mb/s for ZigBee). ZigBee has a longer range (30 m or more as opposed to Wibree’s 10 m range), but this only serves to illustrate the different potential markets of the two. ZigBee can help standardize different smart home technologies such as lighting and heating controls, blind, drapery, and shade controls, and even home appliances such as TVs, DVDs, microwaves, and ovens. Range is less important to Wibree, which is more oriented towards small, low power consumer products such as mobile phones, watches, and input devices, such as mouse and keyboards, as well as toys. The only potential market where the two technologies might compete directly is the medical and sport sensor market; alternatively, both Wibree and ZigBee networks could work side-by-side in different applications over the next few years.
Interview with Nokia
To learn more about Nokia’s Wibree initiative, TFOT interviewed Mr. Harri Tulimaa, Head of Technology Out-Licensing at Nokia.
Q: Would you describe the development of Wibree?
A: The technology was born purely from use cases. In 2001, Nokia Research Center was looking at various user needs and analyzing what can be done with the available connectivity technologies. A vacuum in the personal area network connectivity was identified, as we could think of a lot of interesting use cases for tiny low power devices such as sensors, but realized that there was no suitable technology connecting those to larger devices such as a mobile phone. So we decided to develop a technology to cover this gap in user needs. Wibree has been designed to meet the requirements of low power consumption, small size, and low cost with interoperability based on open specification.
Q: How does Wibree work, and what are its advantages over existing technologies?
A:Wibree is the first open technology offering connectivity between mobile devices or personal computers, and small, button cell battery power devices such as watches, wireless keyboards, toys, and sports sensors. The technology enables new use-cases and growth potential in this market segment.
Wibree is complementary to existing technologies; it does not replace them. As an example, Nokia remains committed to Bluetooth technology and working with the Bluetooth SIG (the Bluetooth Special Interest Group). Bluetooth is a great technology and its wide adoption globally is witness thereof. However, unfortunately, no technology can address all consumer needs without handing away the very foundation of what made it appealing in the first place – the more compromises you end up making due to a vast amount of targeted use cases, the fewer are the relative benefits experienced in any particular use case. Thus, Nokia believes that Bluetooth, as we today understand it, serves some use cases very well, but is not well equipped to serve others. The same will apply to Wibree, meaning that there will be room for both technologies. As a rule of thumb, as the communication becomes more data-intensive, the power consumption benefits of Wibree will diminish compared to Bluetooth. Thus, Bluetooth is better suited for streaming and data-intensive applications such as audio and file transfer, whereas Wibree is better suited for use cases where small amounts of data are transferred. Wibree targets four use case domains, as illustrated on the website. It is expected that mobile phones will carry Bluetooth-Wibree dual-mode implementations, enabling them to make some connections over Bluetooth and others over Wibree.
Q: The Wibree transfer rate is 1 Mb/s. Do you intend to increase this in the future?
A: Wibree technology is optimized to offer ultra low peak, average, and idle mode power consumption. Transfer rate is not the key criterion in those use cases where ultra-low power consumption is needed and data-intensive applications with data rates higher than 1 Mb/s would sacrifice the long battery life.
Q: Wibree operates on 2.4 Ghz frequency – the same as many other technologies (WIFI, BT, ZigBee, to name a few). How can you promise it will work without interference?
A: Nokia has a lot of multiradio experience in the mobile phone environment and we have recognized the interference issues on 2.4 GHz band. Wibree design includes a solution for managing interference based on dynamic channel allocation.
Q: How do you plan to integrate Wibree and Bluetooth?
A: Wibree is an independent new technology that can be implemented based on either stand-alone or dual-mode chips. Stand-alone Wibree chips are used by small, low power, critical devices, whereas Bluetooth host devices, with larger battery capacity, can utilize the dual-mode Bluetooth-Wibree implementation. In mobile phone design, the main benefit of using the dual-mode chip supporting simultaneously Bluetooth and Wibree protocols is achieved by sharing one physical radio and antenna. From the user and application point of view, the key benefit is that a mobile phone or a personal computer becomes a gateway to wide area networks (WAN) and internet for the small low power devices.
Q: Did you consider integrating memory directly into the Wibree chip (similar to HP’s Memory Spot Chip)?
A: This is an implementation issue. It is envisioned that in the longer run Wibree stand-alone module could be part (IP block) of, for example, a watch MCU module.
Q: What will be the power consumption of Wibree (in comparison to Bluetooth, for example)?
A: The maximum transmitted output power of BT class 2 is 4 dBm, ~ 2.5 mW. The total power consumption is much higher. The output power of Wibree standard will be around -6 dBm. Each manufacturer will determine its own transmit power.
Q: How much of an effect will Wibree have on the power consumption of future mobile phones?
A: As the data-intensive applications will continue to be supported by Bluetooth rather than Wibree, the overall power consumption of e.g., a mobile phone will not be significantly affected by Wibree. Wibree technology and its dual-mode functionality enables connection of the power to critical, small devices for which the Bluetooth chip is not an applicable solution.
Q: ZigBee seems to be in direct competition with Wibree, especially in the market of sport and medical sensors. What are Wibree’s advantages over ZigBee?
A:Wibree focuses on low power & low cost communications between mobile phones and small sensor devices, whereas ZigBee focuses on home and industry automation. The mobile phones will be more and more multiradio devices having several radios, many in 2.4 GHz, WiBree is cost- and power-wise optimized for sensor connectivity in this environment, whereas ZigBee results in a lot higher radio activity for fulfilling the same use case, and it is more costly to integrate into mobile phones.
In terms of peak power consumption, Wibree and Zigbee are roughly equal but due to the higher bit rate, Wibree results in better overall power consumption.
Wibree does not support mesh networks as does ZigBee.
Q: What do you see as the main potential market for Wibree?
A: There are multiple verified use cases for low power local connectivity, such as call management from external devices, PC accessories connectivity, mobile phone accessories connectivity, sports, wellness, medical & personal environment sensors, toys, and personal equipment tracking, as examples.
A: The goal being to have the new technology available to the market as fast as possible, Nokia is defining the Wibree interoperability specification, together with a group of leading companies representing semiconductor manufacturers, device vendors, and qualification service providers. The technology will be made broadly available to the industry through an open and preferably existing forum enabling wide adoption of the technology. The forum solution is under evaluation and will be defined by the time the specification is finalized. According to the current estimate, the first commercial version of the interoperability specification will be available during the second quarter of 2007. In addition to these comments about the specification and the forum, Nokia is not releasing any availability statements at this stage. However, Nordic Semiconductor has expressed their excitement about Wibree in our press release: “Consumers don’t like wires and they love compact, portable electronics devices that they can carry with them everywhere without fear of running short on battery power. The mobile phone is the perfect example. But to extend its functionality and allow it to interface wirelessly to a huge range of peripherals, the technical challenge is to ensure minimal power consumption under heavy, daily usage. This is Wibree and it is what consumers have been crying out for. This is also why Nordic Semiconductor is a totally committed partner to enabling this new exciting market for wireless communication and will be ready to ship Wibree chips by the second half of 2007 to help play its part in making Wibree happen.”
Q: Finally, what is the meaning of the name Wibree?
A: “Wi” refers to wireless, but otherwise the name has no definite meaning.