FIELD OF INVENTION
The present invention is in the field of pervasive tracking and monitoring of enterprise objects / assets.
Assets in an organization include humans, vehicles, mobile objects, etc. Our invention is based on the
newly ratified technology of IEEE 802.15.4. The technology gives complete enterprise visibility and leads
to better management and better return on investment's to organizations. The tracking and monitoring
of objects are made through the deploymen of a wireless mesh network. In this invention, we show
how the wireless mesh network is formed in cur system for tracking and management applications. The
tracking system is enabled by the deploying of PervCom's active wireless devices. The wireless devices
consist of three kinds; a wireless sink which has a wired connection to a computer, a wireless router and
a wireless tag. The objects that are to be tracked are attached with the wireless tags. For example, if we
wish to track the movement of humans in an area, tags are carried by them (humans). To know where
the assets are in the area, wireless routers ave placed along important points of the area. Finally, the
wireless sink collects all the information and displays it on the computer to which it is connected by a
wired connection. Our current invention build;, the wireless mesh network through the establishment of
the parent-child relationship among devices. Our mechanism is much simpler than the one specified by
the IEEE 802.15.4 protocol of MLME-ASSOCIATE.request and MLME_ASSQCIATE.response pair. There are
certain intricacies of using this pair and we show how they are averted in our solution. The system of the
invention will have various types of end uses and applications involving tracking and managing of mobile
assets and people, such as tracking of the movement of persons in sensitive and high risk zones, such as
in mines to improve the safety of miners and mine equipment. This improves the surveillance of the
miners and the mine equipment and is of particular importance in the event of an emergency and helps
in mine rescue. The tracking applications are also present in the management of a fleet of trucks in a
campus thus enabling the detection of unauthorized entry into the campus or the movement of a truck
in an unauthorized area of the campus. The s/stem also has applications in the hospital sector where
the movement of doctors, nurses and patients will allow better knowledge of their whereabouts. More
critically, the system can track the location of hospital equipment like oxygen cylinders, defibrillator
trays, first aid trays, mobile ECG machines etc The system has applications in other sectors like retail,
where the location of items in a warehouse ar<» tracked, in logistics, where we can track the movement
of inventory from one warehouse to another, to have an accurate picture of the amount of inventory
left. Thus the system of the invention has numerous industrial applications where it has the potential to
provide accurate and real time information of the location of the assets of the organization thus leading
to better management and improved return on investment.
BACKGROUND ART
It is well known in the art that from time to :ime tracking and monitoring systems have been made
available. Some of the well known and presently available systems of such remote tracking and
monitoring are discussed hereunder.

Standard Wi-Fi (IEEE 802.11) networks have been used to provide location tracking using customer
deployed Wi-Fi hotspots. Aeroscout is a commercial provider of such a system and offers indoor and
outdoor real-time asset location, long range active RFID, choke point visibility and telemetry. A similar
offering is provided by Ekahau where the core of the tracking solution is based on commercially
available Wi-Fi networks. In both systems, active tags are essentially small IEEE 802.11 compliant
wireless devices. These tags are attached to t quipment or carried by people for real time tracking. The
location of a tag is based on location of the Wi-Fi hotspots.
The above related works are based on the IEEE standard of 802.11 (Wi-Fi). Further, the solutions expect
a customer deployed Wi-Fi mesh network i:, already in place. Using the Wi-Fi standard has severe
restrictions as elaborated subsequently. In hazardous areas like the mines, safety precautions are
mandatory, such as, the output power of th? devices should be restricted to within 1 watt and the
devices must be intrinsically safe. Restricting tie output power restricts the effective range of the Wi-Fi
devices. Further, the Wi-Fi devices consume h gh power and it is therefore impractical and infeasible to
run such devices on small batteries like that of size AA.
Another restriction on the solution provided by already deployed Wi-Fi hotspots is that the multi hop
communication is not possible. Therefore, such systems expect the hotspots to be the last mile of a
traditional wired connection where data from the hotspot can then exploit the wired connection to
reach the intended destination. This aspect is severely restrictive in new deployments where there have
been no prior communication networks. For e>ample, in deployments in mines, it is infeasible to deploy
an additional wired network to support the Wi-Fi hotspots. Not only is this prohibitive in terms of cost, it
also puts a burden on the power requirements.
A further restriction of the competing solutions is that they provide no support for the deployment of
Wi-Fi Hotspots. In all these solutions it is assumed that the customer has already placed the hotspots.
This is impractical, as the efficient placement of the hotspots will determine the efficacy of the tracking
and the wireless coverage of the solution.
OBJECTS OF THE INVENTION
It is thus the basic object of the present invention to provide a unique parent-child association
framework which will develop the wireless mesh hierarchy for the pervasive tracking of wireless tags.
Another object of invention is the flexibility provided to the association principle that leads to fault
tolerance in the wireless network configured.
Another object of invention is the bypassing of 1 he associate request/response pair of the IEEE 802.15.4
protocol and the direct way of establishing of the wireless channel parameters.

DETAILS OF THE INVENTION
In this present invention we develop a unique approach to the establishment of the parent child
relationship in the construction of the wire ess network used for the tracking and management of
enterprise objects. The wireless network comprises of wireless tags, wireless routers and the wireless
sink. Each of these wireless devices uses the IEEE 802.35.4 data communication principles. The wireless
tag represents the objects that are monitored. The tag periodically communicates with the closest
router (in its range) about its location. The router in turn forwards the packet received from the tag to
the sink by multi hopping the over other routers. Such a network is shown in figure 1.
In this current invention, we bypass the associate request/response pair of the IEEE 802.15.4 network
building principles. The request/response primitives are generally considered essential in the build-up of
the network, we however show how these piimitives can be avoided and the requisite parameters of
the wireless channel can be set in a direct fashion. We also show how fault tolerance is achieved as a
direct consequence of our mechanism. This fault tolerance cannot be achieved in the conventional
request/response primitives. Our invention can be divided into three homogenous blocks. First, we
elaborate the mechanism in which the parent-child relationship is achieved without the associate
request/response pair. We then show how network fault tolerance is achieved. Finally we show the
setting of the channel parameters in a direct fashion.
a) Parent-Child relationship
Establishing the parent-child relationship between devices in the range of each other is essential in the
proper working of the system. The IEEE 802.15.4 protocol suggests the following way in which a new
device joins the network.
MLME-SCAN.request ->MLME-SCAN.confirm ->MLME-ASSOCIATE.request ->MLME-ASSOCIATE.confirm
Our invention is based on the following principle. When a new wireless device (except the sink) is
switched on (powered on), it performs a channel scan by using the MLME-SCAN.request primitive. The
results are obtained as MLME-BEACON-NOTIfY.indication. All such notify indications have as their
parameters, the responding device's address .ind the strength of the signal received, among others.
These parameters of all notify indications are saved until the MLME-SCAN.confirm is received by the
network layer. The wireless device then inspect* all the saved parameters and selects that device whose
signal strength is the best (maximum). The corresponding address of the device is considered as the
parent of the current device (that is doing the channel scan).
When the device is able to successfully select its parent, it sets its channel parameters (detailed in (c))
and sends a network layer packet destined to the sink (wihose address is always 0x00). The immediate
hop of the packet (i.e. the destination address of the MAC layer packet) is the device's parent address.
When the device's parent receives this packet, it recognizes that the current device is trying to reach the
sink through it. It therefore saves the current device's address as its child. In this way, the parent-child
relationship is achieved. The process we have used thus is simplified to:
MLME-SCAN.request ->MLME-SCAN.confirm

b) Network Fault Tolerance
When a particular device is unable to send a packet to its parent, it resets the information saved as its
parent and repeats the steps elaborated in (a). Note that, the device repeats the procedure only if it is
unable to send to its parent. If the packet to be forwarded to its child fails, the device simply removes
the device as it child. In this way, fault tolerance is achieved. If a device fails due to hardware or power
supply constraints, all of its children choose another nearby device as their parent and are still part of
the network. This fault tolerance is not available in the IEEE 802.15.4 protocol.
c) Direct setting of Channel Parameters
The reception of MLME-ASSOCIATE.confirm automatically sets the device's communication channel to
that of the device sending the associate confirm. This particular way of setting is relatively unknown in
the research community. Since, in our setup, we are not using the associate confirm, we need to set the
channel for the communication to take place. We make this by directly tapping into the PHY layer of the
protocol. Since every device of our system is deployed with a priori knowledge of the channel that's
used for communication, we are in a position to set the channel without having to discover the
communication channel used by other devices in the system (as is the case in the associate confirm
primitive). Note that the IEEE 802.15.4 prolocol provides no mechanism for manually setting the
channel.

BRIEF DESCRIPTION OF ACCOMPANYING FIGURES
Figure 1: is a representative depiction of a wireless mesh network. It shows the multi-hop propagation
of messages from the source to the destination (sink).

WE CLAIM:
1. A unique parent-child association method which will develop the wireless mesh hierarchy for
the pervasive tracking of wireless tags in an IEEE 802.15.4 compliant mesh network for real-time
pervasive tracking, monitoring and management system.
2. A flexible association method that leads to fault tolerance in the wireless network configured.
3. The method of bypassing of the associate request/response pair of the IEEE 802.15.4 protocol
and the direct way of establishing of the wireless channel parameters.

Our invention in this application comprises of three components that makes the build-up of a wireless mesh network of IEEE 802.15.4 compliant wireless devices without using the association primitives of the IEEE 802.154.4 protocol. The wireless mesh network we build is a new way of allowing the message flow between devices in the network. We in particular build the network as a Parent-Child relationship where every device has a single parent. The parent relationship can be re-established in case of an error in sending the packet to its earlier parent. The child relationship is made when a device receives a
packet with the destination in the network header set to the sink (whose address is always 0x00). The bypassing of the associate confirm primitive implies the wireless channel of the device needs to be set by directly tapping into the physical layer of the protocol. This is because of the relatively obscure way in
which the IEEE 802.15.4 primitive automatically sets the wireless communication channel as that of the device from which the associate confirm is obtained. Through this invention, we show how the management of mobile assets can be made simple and efficient. In particular, our invention allows for ease of deployment of IEEE 802.15.4 compliant wireless devices where an important factor of fault tolerance is provided. In the case of hazards where certain devices are damaged due to accidents such as a fire, the network recovers and is critical in tracking and informing assets carrying the wireless tags
of the hazard. This simple example shows how our system of IEEE 802.15.4 based tracking and
monitoring system can be critical in rescue operations in cases of accidents leading to saving lives and equipment.