August, 2005
Brethour, Time DomainSlide 1
doc.: IEEE 802.15-05-0491-00-004a
Submission
Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [Ranging with the 15.4 MAC]
Date Submitted: [3 August, 2005]
Source: [Vern Brethour] Company [Time Domain Corp.]Address [7057 Old Madison Pike; Suite 250; Huntsville, Alabama 35806; USA]Voice:[(256) 428-6331], FAX: [(256) 922-0387], E-Mail: [[email protected]]
Re: [802.15.4a.]
Abstract: [A review of the 15.4a applications asking for location awareness & a possible approach for serving a high number of tracked nodes.]
Purpose: [To promote discussion in 802.15.4a.]
Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.
Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.
August, 2005
Brethour, Time DomainSlide 2
doc.: IEEE 802.15-05-0491-00-004a
Submission
Applications for UWB ranging & the 15.4 MAC
August, 2005
Brethour, Time DomainSlide 3
doc.: IEEE 802.15-05-0491-00-004a
Submission
First, a review of applications.
• The next few slides list the applications that are usually discussed in the context of UWB ranging and positioning.
August, 2005
Brethour, Time DomainSlide 4
doc.: IEEE 802.15-05-0491-00-004a
Submission
Safety of life.
• Safety interlock on dangerous equipment: Some nasty machine turns off when humans (wearing appropriate radios) get too close.
• Tracking firefighters in dangerous environments.
• Tracking soldiers or policemen in hostile buildings.
August, 2005
Brethour, Time DomainSlide 5
doc.: IEEE 802.15-05-0491-00-004a
Submission
Tracking material
• Pallets in warehouses.• Shipping containers in ports.• Cars in huge lots.• Luggage in airports & ports.• Moneybags in armored trucks & vaults.• Equipment in hospitals.
August, 2005
Brethour, Time DomainSlide 6
doc.: IEEE 802.15-05-0491-00-004a
Submission
Automatic meter reading?
• In the 4a applications, this was listed as an application for “location awareness”. (???)
• In other market characterizations, this is strictly a communications application.
• The meter has an ID number associated with an account to be billed. We usually want to know the meter reading, not the location.
August, 2005
Brethour, Time DomainSlide 7
doc.: IEEE 802.15-05-0491-00-004a
Submission
Tracking animals
• Pets and Agricultural livestock are self propelled high value assets with “minds” of their own. It’s useful to know where they are and where they have been. (How often has Bessie been to the feed trough?)
August, 2005
Brethour, Time DomainSlide 8
doc.: IEEE 802.15-05-0491-00-004a
Submission
Tracking people
• Children in amusement parks & malls
• Workers on hazardous job sites
• Alzheimer’s patients
• Prisoners
• First Responders
August, 2005
Brethour, Time DomainSlide 9
doc.: IEEE 802.15-05-0491-00-004a
Submission
The “most asked for” application.
• This is hands down the most requested application in Huntsville Alabama. Second place is not even close:
Tracking Teenage Daughters.
August, 2005
Brethour, Time DomainSlide 10
doc.: IEEE 802.15-05-0491-00-004a
Submission
Now, let’s go through the applications again and look at what the network needs to support them.
• Generalizations follow: let’s look for the trends.
August, 2005
Brethour, Time DomainSlide 11
doc.: IEEE 802.15-05-0491-00-004a
Submission
Safety of life applications
• Support of mobility is essential.
• High update rates are required.
• Cost and battery life are not so critical.
August, 2005
Brethour, Time DomainSlide 12
doc.: IEEE 802.15-05-0491-00-004a
Submission
Tracking material
• This is probably the best fit for 4a.
• Pallets of dog food in a warehouse need to be findable, but they don’t move around often and do not need to be tracked while in motion.
• Some high value assets (money bags) need high update rates and tolerance of mobility so they can be detected when they try to wander off.
August, 2005
Brethour, Time DomainSlide 13
doc.: IEEE 802.15-05-0491-00-004a
Submission
Location Awareness for meter reading? Where is the meter?
August, 2005
Brethour, Time DomainSlide 14
doc.: IEEE 802.15-05-0491-00-004a
Submission
The meter is right here on the side of the house. (Same place it was last month.) The REAL question the meter
reader cares about: Where is the pit bull?
August, 2005
Brethour, Time DomainSlide 15
doc.: IEEE 802.15-05-0491-00-004a
Submission
Automatic meter reading.
• This is an excellent application for UWB and 15.4a communications.
• I do not believe that this is an application requiring location awareness.
August, 2005
Brethour, Time DomainSlide 16
doc.: IEEE 802.15-05-0491-00-004a
Submission
Tracking animals
• High update rates are usually required.
• This might be an application that can be served by 15.4a if we only care occasionally where the animals are.
August, 2005
Brethour, Time DomainSlide 17
doc.: IEEE 802.15-05-0491-00-004a
Submission
Tracking People
• In general, the goal is detecting people going where they should not (because they are mobile).
• This requires a high update rate.
August, 2005
Brethour, Time DomainSlide 18
doc.: IEEE 802.15-05-0491-00-004a
Submission
What does this mean for the 4a MAC?
• High update rates (implying high traffic levels on the air) might not be appropriate for the 4a MAC.
• Many of the applications for UWB location are calling for high update rates.
• Even the support of “mode 2” ranging will be difficult.
August, 2005
Brethour, Time DomainSlide 19
doc.: IEEE 802.15-05-0491-00-004a
Submission
Remember “mode 2” ranging?
• We said in Australia that we wanted to support this.
• The red nodes (typically in the fixed infrastructure) need a common high accuracy clock.
Key:Sync PulseLocation PulseTDOA backhaul
Mode 2 - Active
controller
reference node
SOI
August, 2005
Brethour, Time DomainSlide 20
doc.: IEEE 802.15-05-0491-00-004a
Submission
The establishment and maintenance of the high accuracy clock will be tough with the 15.4 MAC
• Clock sync usually wants timestamps and oscillator drift rate information exchanged regularly with atomic message swaps.
Mode 2 - Active
SOI
Black arrows are clock sync messages.
August, 2005
Brethour, Time DomainSlide 21
doc.: IEEE 802.15-05-0491-00-004a
Submission
Maybe, we let the Mode 2 infrastructure be outside of the standard.
Key:Sync PulseLocation PulseTDOA backhaul
Mode 2 - Active
controller
reference node
SOI
The red nodes do their clock sync thing some proprietary way that is not part of the standard.
All red nodes in a particular installation would have to be from the same vendor (interoperability of infrastructure nodes is not guaranteed by the standard.)
We define the behavior of the blue nodes as 15.4a standard behavior and blue nodes can come from any vendor and work with any infrastructure.
August, 2005
Brethour, Time DomainSlide 22
doc.: IEEE 802.15-05-0491-00-004a
Submission
The warehouse application:The warehouse infrastructure is made of proprietary radios which are not necessarily interoperable with infrastructure radios from other vendors. (Infrastructure is potentially wired into the building.)
Screwed to each pallet is a standard 4a device from any vendor that will work in any infrastructure. This is a perfect “15.4” fit: inexpensive, long battery life, low duty cycle, etc.
August, 2005
Brethour, Time DomainSlide 23
doc.: IEEE 802.15-05-0491-00-004a
Submission
The proprietary infrastructure.
• This might be the way to let our MAC (that wants to see low traffic rates on the air) still support tracking of very large quantities of nodes.
• Don’t know what else to do for high node populations. Ideas are welcome.