Summary

June 30, 2010

In the process of writing this blog I tried to present you the importance of WBAN 802.15.4 standard in its 2010 version. I hope that I managed to at least direct the reader in proper direction of investigating the way it’s being standardized and how it will influence the market and society. In this post I will gather this information in a more compact form.

This summary will be divided into several parts:

What is WBAN

-          Medical usage

-          Sport usage

-          Other

How it works?

How is it different from previous version?

What about competition?

Why is it going to be the successive?

What is WBAN?

WBAN as a shortcut of Wireless Body Area Network (or sometimes called Wireless Personal Area Network) is a network of nodes that are deployed on the surface of a person’s body. The number of nodes is normally in range of 10-20 on one person. The most important use of such a network is to measure different markers of the person under test and send this data to the main node. Of course this main node can send this data to remote location with use of any of available ambient networks (GSM, WIFI, satellite etc).

The biggest requirement for such inter-node communication is to keep the power usage as low as possible, this is connected with actually two reasons – to assure long operations (battery life) and to limit the radiation to which the person is subjected. This second reason is especially important in cases where the use is prolonged and the person under test is a hospital patient, where radiation over long period of time could lead to some additional illnesses or at least result in change of medical test results.

With the direction of modern technology evolution we can expect that, what was previously only possible in sci-fi movies, will become normality. People will be connected to the grid gathering information about their state of health, their location or mood. The possibilities are endless, but in current state of this technology it’s most appealing in three interesting aspects:

Medical usage

Hospitals and health care in general are places where technological development has a very welcoming ground. It’s is here, where the idea of WBAN’s have the beginning. This solution will have a great application in constant wireless monitoring of patient’s health condition, their vitality and even habits. Each of patients’ could have several nodes, each placed in the most appropriate place on the body and each testing its specific parameter. With such  information, especially in long term monitoring, doctors could really make diagnosis based on more information than before.

Also in this category we can see the solutions to monitor people at home, especially elderly people, who can’t fully control their situation, and sometimes need additional help.
Sport usage

This application is dramatically different. It’s directed on young active people, who exercise a lot, and who would like to have accurate and constant information about their training progress. In this category we could list a big number of different nodes that can give useful information, but just to mention the most important: heart beat sensor, pedometer, temperature sensor, integrated bike sensors (speed, cadence etc). This application is even more important than one could think, as people actively exercising are mostly young, well situated and educated, and what’s most important not afraid of new technologies, maybe even fond of the gadgets they use.

Other usage

There are hundreds of ideas how to use WBAN technology. We can see a future of modern clothing with this radio communication embedded, we can see it as a way of keeping all of our devices in synch, but also it can be used as the modern solution on the areas of war conflicts. Army already was developing this kind of technology for several years, but it’s possible that if the commercial standard will give it even more possibilities and performance, we can see  interest in this standard also from that direction.

How it works?

The most important part of this standard in technical aspect is the physical medium of communication. As the wireless nature of communication can bring totally different results depending on the specific technology used, it is crucial to choose it wisely.

In case of 802.15.4 standard (2010 version), we can use three different radio communication specifications: Ultra wide band, Narrow band, Human Body Communication. It’s important to note first and last one of them. Ultra wide band transmits data with very little power but on a very broad frequency band – it gives two advantages: it’s very hard to interfere with this signal, and this signal is very improbable to interfere with any other device. It’s especially important for use in medical applications, where any interferences with a life support systems can have a catastrophic effect.

Second kind of radio interface has a very different advantage: it’s construction is as simple as possible. There is even no parts responsible directly for RF  mixing- everything until the antenna is done in digital domain, using special kind of bit arrangement.

This standard actually doesn’t limit its scope to RF part. 2010 version is also focused on delivering full solution for WBAN networks. We can see that the network topology is described as start network, but we could also expect to see a development of standard to use a multi hop network. Security features and MAC layer are also being described, to get the standard on the level which will allow all the manufactures to build a network of devices fully compatible with each other – the main idea behind standardizing WBAN in such a shape.

How it differs from previous version?

Previous version was a basis for ZigBee standard. It was only focused on the part of MAC layer and physical description medium (RF part). It was limited in its description of higher services and aspects. For example there was no network topology except point to point communication. That meant that for a fully operational product for WBAN applications, there was a need for further specifications of these aspects. ZigBee was such an attempt, but it was done several years ago. As the technology went further the development of new version was decided to be the best option. In this sense currently the focus of standard was broadened and will cover also higher parts and services of protocol.

That means that we will have a standardized in full WBAN communication with more complicated network topology and security. It’s the biggest difference that now it won’t be necessary to build additional standard on top of 802.15.4.

Also with new version, as it was described in previous paragraph, two new radio communication mediums were described – UWB and HBC, which brings new big improvements.

What about competition?

There is only one real competition for new 802.15.4 standard- an old 802.15.4 standard with its ZigBee addition. It can be a hard question in which way market will turn in few years, especially due to high interest in ZigBee between industry companies. In my belief advantages of new standard will make the change easier and industry will be more eager to switch.

Until the standard is fully described, or at least there is draft finished, it’s hard to divagate on the topic of how big difference will new 802.15.4 make, but we can only hope that it will be important enough to make ZigBee follow its lead.

Also there are several more standards of wireless communication for short distances, but actually they have not so much focus on the topic of power efficiency – Bluetooth or WiFi limit usage time of use even for a fairly big and complicated smartphones, not to mention small and cheap WBAN nodes. Thus the choice of WBAN standard in future will be between old and new 802.15.4.

Why is it going to be a success?

Modern world, even if it’s not fully aware of that fact, needs an introduction of WBAN’s to mass usage. As idea behind WBAN can only be realized when each device can communicate with each other, the process of standardization is a fundament on which the whole technology will be built. I believe that with a proper standard, which current draft can become, this technology has a very bright future. ZigBee is not that well situated on the market outside of industrial solutions of building monitoring, so it’s longer existence on the market may not have so big influence on the choice which will have to be made in the future- old or new 802.15.4. The advantages of new version can be seen very easily, so I think the end result will be in its favor.


802.15.4 vs ZigBee

June 29, 2010

As it was mentioned before ZigBee standard is the most direct competition for currently developed WBAN standard. It is even more direct as ZigBee is based on previous version of 802.15.4 (from 2003). Since that time a lot has changed thus a new standard is developed.

In this post I will try to answer a question if we should be afraid that success of new implementation will be crippled by ZigBee older brother.

At first it’s important to show how ZigBee is related to its root 802.15.4. As the old 802.15.4 is focused only on mac layer and physical media specification, ZigBee was developed to build on top of that a fully operational network system with necessary functions e.x. security and encryption. This relation can be described in few points:

  • 802.15.4 (2006) was designed to allow point to point energy sufficient communication
  • ZigBee adds on top of that more services: star topology routing, encryption, application services
  • ZigBee creates semi-centralized network. It allows only end devices to sleep (to reduce power but keep the main node waiting for communication)

In case of new version of 802.15.4 the focus was broadened to include this parts as well in the basic standard. Also the additional options for physical layer were defined to allow even better adaptation of final solution to the application.

A table and short description is shown to illustrate differences between both standards.

ZigBee New 802.15.4
Physical medium Narrow band Narrow band, UWB, HBC
Bands ~900MHz ~900Mhz, 3-10Ghz, 16Mhz, 27MHz
Range 10-100m 10m
Bitrate 20,40,250kbps Upto 100mbps (with UWB)
Power consumption Low Low
Typical application Mostly industrial, building monitoring Sensor nodes in WBAN applications
Complexity Low Very low (with HBC)
Security 128AES 128AES

We can see that a new standard has a lot of advantages over ZigBee –mostly it’s better suited for short distance communication on the body surface. It can’t be forgotten that with use of UWB, as it was already shown, new standard is more suited for medical applications:

  • Low interference with medical equipment
  • Lowest possible effect on living tissue

Thus even with so many common roots, these both standards are quite different. It’s possible that with introduction of new 802.15.4 standard, ZigBee will be adapted to be compatible with new version, or the new version finally will add some way of interoperability with ZigBee. That would help to answer the question of who will win in this confrontation. Unfortunately at this stage of standard development it’s hard to determine how it will end.


Wireless body area networks – some inspiration

June 28, 2010

A very interesting video of presentation of Eric Topol on TED.com:

http://www.ted.com/talks/eric_topol_the_wireless_future_of_medicine.html


Why WBAN technology will become important standard on the market – medical market possibilities

June 28, 2010

Studies of Netherland seniors over the last 10 years indicate that up to 50 percent of seniors are interested in smart-home applications to aid in health, first responders’ reaction times and security improvement.

As it was mentioned before, WBAN technology was at first focused on medical applications. Of course currently it’s not limited to this field, but I will start with showing why I think that it has a great future and there is a market emerging for such a kind of solution. Most of information included in this post can be found in a document by Dr. Russ Ricci, created for IBM’s Healthcare Services. It’s available under this link: http://www.researchandmarkets.com/reports/836543/wireless_communications_trends_health_care.pdf

According to Russ Ricci the modern medicine is to be influenced by many forces that will result in great changes in next 10 years. The main change will be that the modern technologies will not only help doctors to treat illnesses, but also will allow a constant monitoring of people that are not even ill at the moment. That will in effect be a rise of a practice called “biognosis”. Biognosis is a word meaning “life knowledge” and is used by Dr. Ricci to describe a combination of both diagnosis of disease and medical prevention. This will be realized be use of sophisticated monitoring devices that are exactly a focus of WBAN technology.

Specification of this standard is just a first step of creating a national bank of medical information about people’s health, which will be feed online and analyzed in real time.

It is becoming even more important as eastern societies median age is growing each year. With longer life expectancy (median age of American increased from 32.9 years in 1990 to 35.3 years in 2000, according to Census 2000) and better availability of medical treatment, medicine is a very important part of market. It is predicted that in 2012 global market of medical devices will exceed 70 Billion dollars. It will probably grow even higher in the following years, as a cost of just heart failures in US is 37B$ per year – if we can use a technology to prevent different illnesses, the spending on technology will fund itself.

It is important that in this application WBAN will create a base for development of other standards. Specifically mentioned by Dr. Ricci standards of clinical information systems, which will be used to keep the data gathered during monitoring. It is predicted that it will take next 10 years and that it will occur in three distinct phases.

In next four years a first stage will take place. It will be Activation stage, when different companies will start to develop such systems and try to meet requirements of Health Insurance Portability and Accountability Act. It will be forced by employer groups as well as by consumer’s requirements.

Next stage of Standardization will take next 4-7 years. It will force suppliers to comply with the standard and unify to some extent their implementations.

Last stage of Convergence that should occur in 10 years from now will result in a unified solution for individual biognosis with monitoring/clinical centers and care delivery.

If we assume that this summary is correct, we see that WBAN standard is on the edge of being on time- it should have already some good ground on the market or at least some industry support before the beginning of Standardization process, if it is supposed to play important part in this solution.

Also we can see that (information from ZigBee Alliance document: http://www.zigbee.org/imwp/download.asp?ContentID=15585), number of wireless nodes deployed in medical solution is growing faster each year:

At the moment the numbers may not be shocking, but concerning the trend to rapid growth this summary shows that medical application itself is worth billions, thus making WBAN standard very crucial for near and far future.

WBAN in medical application – use cases

Market plans developed by ZigBee Alliance take into consideration several use cases for medical applications:

-          Chronic Disease Monitoring

As the costs of treating diseases in US contribute to around 75% of total health care costs, it is the most important use case of all mentioned. Chronic disease are a wide range of illnesses: heart diseases, diabetes, asthma and many more. In most cases these diseases require constant long term monitoring, to assure proper level of treatment and correct diagnosis

-          Episodic Patient Monitoring

This use case focuses on periodical testing of patient’s health status in order to keep a long term data on his/hers health state. It helps doctors to determine trends in patient’s EKG, blood pressure etc. Information gathered in this use case is sent to the remote data center, and kept there for further reference.

-          Patients Alarm Monitoring

Monitoring equipment in this category targets constant monitoring in case of medical emergency (heart attack etc). Data can be processed in two ways- locally or remotely. In case of local processing, the data is checked for sings of emergency and if such occurs the alarm signal is sent to the response center.

-          Elderly people monitoring

This type of monitoring apart from normal vital signals checking also can record other data helping to determine wellbeing of old person. It can information on a current place where a patient is, or a distress signal in case of need of assistance. Such information could be accessed (with permission) by the members of family remotely.

Such monitoring is done in a configuration consisting of two closed loops – one inner home loop, and second one outer loop which consist of professional medical care out of home.


Why WBAN technology will become important standard on the market

June 27, 2010

WBAN standard in the form that is developed by IEEE has no direct competition. Of course on the market there are several different wireless standards for short distances (Bluetooth, ZigBee to name the most important ones), but none of them target WBAN application with such accuracy as current specification of WBAN (2010). ZigBee, as it’s built based on old specification of 802.15.4 has some aspirations for this part of the market, but 2010 is more suitable for modern market needs. The biggest difference is that newer standard ads  a possibility to use UWB radio.

Bluetooth technology has the biggest coverage on the market. According to “Worldwide Bluetooth Semiconductor 2008-2012 Forecast” in 2012 market of Bluetooth IC’s will reach a level of 3.3B$. It is a massive competition, but we have to take into consideration that there is a big difference between BT and WBAN which partially is based on Ultra Wideband radio. Bluetooth doesn’t focus that much on the topic of low power consumption, what is most important in WBAN applications. Bluetooth transmitter has a transmit power of 1mW, where WBAN solution can use much lower powers ~100uW for UWB.

Also with Human Body Communications radio WBAN can offer much simpler radio design, what further brings the power consumption and costs down. This technology is specifically targeting Personal Network applications and thus is much suited for the task.

As the standard is still in quite initial stage of the process, and draft is not yet finished, it is hard to say what technology solutions will be used in finial version. We can only assume at the moment that the network topology will allow multihop communication, which in case of WBAN is very important idea, allowing to limit transmission power of each node to the minimal possible value that still keeps connection to nearest nodes, but doesn’t require communication between each nodes.

We have to look at WBAN network more as a missing element, which didn’t have its direct predecessor on the market, then as an additional standard of wireless communication. Even though it is planned to use UWB technology as a transmission technology, it doesn’t directly compete with Bluetooth and Zigbee, which normally compete with UWB. It is due to some additional requirements that WBAN application has. I will show them in this post:

Low power consumption

As in wireless body area networks we don’t require high bandwidth in most cases we can greatly  reduce power consumption of transmitter/receiver. In case of Bluetooth, power consumption is at least 10x about the required one. In case of ZigBee it’s much lower, but still on the high side.

UWB can take advantage of its short burst communication and reduce greatly average power in exchange for unnecessarily high bit rate. Also application of Human Body Communication, as it was mentioned, tries the other approach to simplify the transmitter and receiver to extreme, thus limiting the power lost in transceiver itself.
Low interference with medical equipment

UWB with its spread spectrum (>500MHz) communication is much less expected to create interference for medical, and not only, machinery. This fact is extremely important for WBAN, where the initial idea comes from medical monitoring requirements. Bluetooth as well as ZigBee are narrow band radios, thus have a much greater probability of creating interferences.

Lowest possible effect on living tissue

In case of transceivers that are supposed to be worn for extended periods of time, the health concerns become even more of a problem then with current applications. With spread spectrum communication and ultra low power of transmission, UWB becomes the best solution of WBAN application. In this sense Bluetooth or ZigBee can’t get even close to what UWB represents.


IEEE standard development process

June 27, 2010

A process of standard development consists of 8 stages:

  • Initiate
    • Initiate the project
    • Develop the working group
  • Produce
    • Write the draft
    • Ballot the draft
    • Get the final approval
  • Manage
    • Publish the standard
    • Reaffirm the standard
    • IEEE standards forms

A presentation, which can be accessed at http://grouper.ieee.org/groups/1620/OverviewOfIEEEProcess/P1620_overview.ppt describes shortly how the IEEE standard is developed. Information available there will be used to show specific steps (graphs cited from presentation). (click for better picture)

As we can see the process starts with the idea of the standard. It is normally created by a group of people, but responsibility for this idea is assumed by the sponsor. A sponsor is not a single person, but it is usually a society, or already existing committee.

Afterwards idea itself is transformed into a legal document called PAR. It has to describe for example legal issues connected with copyrights. Each PAR has to be approved before the standardization process continues. Approval is done by New Standards Committee.

A working group assigned to a given standard is then responsible for creating a draft of the standard, as well as for a revision.

A finalized draft is then balloted by a balloting group formed by the sponsor. This step has to achieve consensus to be followed by the next step.

After balloting process the standard is sent to Review Committee and Standards Board to be approved again. This step has to finish before a time limit of 4 years (from PAR to approval).

Of course after this standardization process is finished the standard has to be published, so interested parties can implement it. What is interesting, such a standard has to be reaffirmed before the end of its five year validity period.

This graph presents a process of approving PAR. It starts with finding a sponsor. After this step the Project Authorization Request is created and submitted to NesCom. If PAR is complete and fulfills basic requirements, it’s presented for a review to NesCom Standards board. If it is approved in the current version, the process of standardization can continue to workgroup stage.

Work group is responsible for creating a draft document of standard. It is done after specification of goals and schedule. The finalized draft is presented for a review to technical editor, who decides if it needs any changes. Such revised document can be sent for balloting stage.

Balloting stage is a fairly complicated process. It starts with a sponsor forming a balloting group. As on its members depends a representation of interests of each company, it is important that it will result in a balanced group. Balloting process usually takes 30 days. Each member has to answer with one of three votes: approve, disapprove, abstain.

If less than 75% of members answered in a given time the ballot failed and has to be repeated. Next it’s important to address comments received and check if at least 75% of votes were approving. If it’s the case and there are no negative ballots, the standard can be sent to Standards Board.

This step is necessary to determine if all documents and forms are in order and also to get approval from Standards Board after reviewing the proposal. If the standard is approved, then the final step of publishing it is done. At this point a 5 year validity period starts, which will be concluded with reaffirmation process.

This shows a basic process of standardization in IEEE environment. Wireless Body area Network currently is at the stage of draft creation.


Influence of WBAN standard on product innovation

June 24, 2010

Standards commonly are considered to have a negative influence on innovation. This is a result of the fact, that after adaptation of standard by market, it is hard to introduce new technologies in a given field, without changing this standard. Of course this situation will take place with this standard as well, but we have to consider other aspect of WBAN. As this technology introduces a totally new aspect of using wireless technology, it can have a very positive influence on innovation. Possibility of joining all personal portable devices into one constantly active network opens new opportunities for innovation. A personal trainer in a person’s cell phone, with information from step meter, gps and heart beat sensor and sending a voice feedback to mp3 player is just an idea from the top of one’s head that is only possible with realization of commonly accepted wireless communication standard. It seems that there are more positive aspects for innovation due to introduction of this standard than negatives. Especially that idea of wireless body area network is based on interoperability, thus it cannot exist without a proper standard.


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