U.S. patent application number 11/074910 was filed with the patent office on 2006-09-14 for method and apparatus for network formation.
Invention is credited to Vernon A. Allen, Oleg Andric, Wayne W. Chiou, Ralph L. D'Souza, Minh T. Pham.
Application Number | 20060205409 11/074910 |
Document ID | / |
Family ID | 36953688 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060205409 |
Kind Code |
A1 |
Chiou; Wayne W. ; et
al. |
September 14, 2006 |
Method and apparatus for network formation
Abstract
When a requesting node (402) has routing capabilities and
attempts to join a network and there are no association slots
available, the requesting node (402) will send an association
message to a potential root node (401). If the root node (401) has
reached the maximum number of links, and has a non-routing capable
node (403) associated with it, the root node (401) will send a
message to the non-routing capable node (403), instructing it to
disassociate and attempt to re-associate at a later time. A message
is then sent to the requesting node (402) for it to associate with
the root node (401).
Inventors: |
Chiou; Wayne W.; (Sunrise,
FL) ; Allen; Vernon A.; (Fort Lauderdale, FL)
; Andric; Oleg; (West Palm Beach, FL) ; D'Souza;
Ralph L.; (Sunrise, FL) ; Pham; Minh T.;
(Boynton Beach, FL) |
Correspondence
Address: |
MOTOROLA, INC.
1303 EAST ALGONQUIN ROAD
IL01/3RD
SCHAUMBURG
IL
60196
US
|
Family ID: |
36953688 |
Appl. No.: |
11/074910 |
Filed: |
March 8, 2005 |
Current U.S.
Class: |
455/445 ;
455/450 |
Current CPC
Class: |
H04W 40/246 20130101;
H04W 76/10 20180201; H04W 84/18 20130101 |
Class at
Publication: |
455/445 ;
455/450 |
International
Class: |
H04Q 7/20 20060101
H04Q007/20 |
Claims
1. A method for network formation, the method comprising the steps
of: receiving a request to form a communication link with a
requesting node; determining if a maximum number of links has been
achieved; determining a node to disassociate communication with,
wherein the step of determining the node to disassociate
communication with is based on whether or not the node is a routing
node or a non-routing node, and wherein a routing node is a node
capable of routing data and a non-routing node is a node incapable
of routing data; in response to the request to form the link and
the determination that a maximum number of links has been achieved,
disassociating communication to the node; and forming a
communication link with the requesting node.
2. The method of claim 1 wherein the step of receiving the request
to form the communication link comprises the step of receiving a
request to form an ad-hoc communication link.
3. The method of claim 1 wherein the step of disassociating
communication to the node comprises the step of transmitting a
disassociation message to the node.
4. The method of claim 1 wherein the step of forming the
communication link with the requesting node comprises the step of
transmitting a message to the requesting node, instructing the
requesting node to form the link.
5. The method of claim 1 further comprising the steps of:
determining if the requesting node is a routing node.
6. The method of claim 1 further comprising the step of:
determining if any associated nodes are non-routing nodes.
7. A method for network formation, the method comprising the steps
of: receiving a request to form a communication link with a
requesting node; determining if a maximum number of links has been
achieved; determining if the requesting node is a routing node;
determining if any associated nodes are non-routing nodes wherein a
routing node is a node capable of routing data and a non-routing
node is a node incapable of routing data; in response to the
determination that any associated nodes are non-routing nodes,
breaking communication to a non-routing node; and forming a
communication link with the requesting node.
8. The method of claim 7 wherein the step of receiving the request
to form the communication link comprises the step of receiving a
request to form an ad-hoc communication link.
9. The method of claim 8 wherein the step of breaking communication
to the non-routing node comprises the step of transmitting a
disassociation message to the non-routing node.
10. The method of claim 9 wherein the step of forming the
communication link with the requesting node comprises the step of
transmitting a message to the requesting node.
11. An apparatus comprising: a receiver receiving a request to form
a communication link with a requesting node; and logic circuitry
determining if a maximum number of links has been achieved and in
response to the request to form the association link and the
determination that the maximum number of links has been achieved,
determining a node to disassociate communication with,
disassociating communication with the node and forming a
communication link with the requesting node, wherein the step of
determining the node to disassociate communication with is based on
whether or not the node is a routing node or a non-routing node,
wherein a routing node is a node capable of routing data and a
non-routing node is a node incapable of routing data.
12. The apparatus of claim 11 wherein the request to form the
communication link comprises a request to form an ad-hoc
communication link.
13. The apparatus of claim 11 wherein the disassociation with the
node takes place by the logic circuitry instructing a transmitter
to transmit a disassociation message to the node.
14. The apparatus of claim 11 wherein the communication link is
formed with the requesting node by transmitting a message to the
requesting node.
15. The method of claim 1 wherein only nodes that are non-routing
nodes are chosen for disassociation.
16. The apparatus of claim 1 wherein only nodes that are
non-routing nodes are chosen for disassociation.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to network formation
and in particular, to a method and apparatus for ad-hoc network
formation.
BACKGROUND OF THE INVENTION
[0002] In a wireless network with routing capable and non-routing
capable nodes, it is possible that non-routing capable nodes will
prevent additional nodes from joining the network. More
particularly, since nodes within an ad-hoc communication system may
have a maximum number of connections to other nodes, if non-routing
nodes join the network before the routing nodes, then the maximum
number of nodes capable of joining the network may be limited. This
is illustrated in FIG. 1.
[0003] As shown in FIG. 1 network 100 has formed with two
non-routing nodes 102 connected to routing node 101. As is evident,
if all routing capable nodes can only support 2 associated nodes
and two non-routing capable nodes join first to the root node, then
this network can only support a maximum of 3 nodes. On the other
hand, if two routing capable nodes join the root node then this
network can support at least 7 nodes (FIG. 2). Therefore a need
exists for a method and apparatus for forming a network that
prevents non-routing nodes from limiting the number of nodes that
can join a network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] FIG. 1 is a block diagram illustrating network
formation.
[0005] FIG. 2 is a block diagram illustrating network
formation.
[0006] FIG. 3 is a block diagram of an ad-hoc network.
[0007] FIG. 4 is a block diagram of an ad-hoc network illustrating
network formation.
[0008] FIG. 5 is a block diagram of a node.
[0009] FIG. 6 is a flow chart showing operation of the node of FIG.
5.
DETAILED DESCRIPTION OF THE DRAWINGS
[0010] In order to address the above-mentioned need, a method and
apparatus for network formation is provided herein. When a
requesting node has routing capabilities and attempts to join a
network and there are no association slots available, the
requesting node will send an association message to a potential
root node. If the root node has reached the maximum number of
links, and has a non-routing capable node associated with it, the
root node will send a message to the non-routing capable node,
instructing it to disassociate and attempt to re-associate at a
later time. A message is then sent to the requesting node for it to
associate with the root node. This will result in a net increase of
available association slots for the other nodes to associate to the
network. If the root node does not have non-routing capable nodes
associated to it, a refusal message is sent to the requesting node.
The requesting node will then repeat the query with other potential
root nodes until it can associate with the network.
[0011] The present invention encompasses a method for network
formation. The method comprises the steps of receiving a request to
form a communication link with a requesting node and determining if
a maximum number of links has been achieved. In response to the
request to form the link and the determination, communication to a
non-routing node is broken and a communication link is formed with
the requesting node.
[0012] The present additionally invention encompasses a method for
network formation. The method comprises the steps of receiving a
request to form a communication link with a requesting node,
determining if a maximum number of links has been achieved,
determining if the requesting node is a routing node, and
determining if any associated nodes are non-routing nodes. In
response to the determinations, communication to a non-routing node
is broken and a communication link with the requesting node is
formed.
[0013] The present invention additionally encompasses an apparatus
comprising a receiver receiving a request to form a communication
link with a requesting node, and logic circuitry determining if a
maximum number of links has been achieved and in response to the
request to form the association link and the determination,
disassociating communication with a non-routing node and forming a
communication link with the requesting node.
[0014] Turning now to the drawings, wherein like numerals designate
like components, FIG. 3 is a block diagram of network 300. Network
300 preferably utilizes a communication system protocol defined by
the 802.15.3 Wireless Personal Area Networks for High Data Rates
standard, or the IEEE 802.15.4 Low Rate Wireless Personal Area
Networks standard. One of ordinary skill in the art will recognize
that other communication system protocols may be utilized without
varying from the scope of the invention. For example, communication
system 100 may utilize communication system protocols such as, but
not limited to, Ad-hoc On Demand Distance Vector Routing (AODV),
Dynamic Source Routing (DSR), Temporally-Ordered Routing Algorithm
(TORA), Bluetooth.TM. standard (IEEE Standard 802.15.1), . . . ,
etc.
[0015] As shown, network 300 includes a number of routing nodes 301
and non-routing nodes 302. Nodes 301-302 represent devices that
communicate with each other through wireless communication, and can
be transportable (mobile) or they can be fixed in a given place.
Nodes 301-302 can include, for example, transceiver security tags
attached to valuable assets such as lap top computers, or be
embedded in wireless communication devices including cellular
telephones.
[0016] During operation of network 300, nodes become associated
with each other for routing purposes, with transmissions between
two nodes generally taking place through intervening nodes. The
intervening nodes receive a source transmission, and "repeat" the
source transmission until the source transmission reaches its
destination node. As discussed above, many networks comprise nodes
that are incapable of routing data. If a non-routing node 302 joins
network 300 before a routing node 301, then the maximum number of
nodes capable of joining the network may be limited. In order to
address this issue, when a node receives a request for association,
the node will attempt to associate the requesting node. If,
however, the node has reached a maximum number of links, the node
will be unable to associate the requesting node. In this situation,
the node will determine if the requesting node is a routing node
and if any associated node is a non-routing node. If both
conditions are true, the non-routing node will be disassociated and
replaced by the requesting node. This procedure is illustrated in
FIG. 4.
[0017] As shown in FIG. 4, node 402 requests an association with
node 401 at time period 404. If the maximum number of links for
this network is two, then the association cannot be completed since
node 401 has two existing links. If node 401 determines that node
402 is capable of routing, and that an associated node (e.g., node
403) is a non-routing node, then a non-routing node is forced to
disassociate with node 401. This is accomplished by node 401
sending a disassociation message to non-routing node 403 at time
period 405. In response, node 403 disassociates with node 401 at
time period 406, and an "OK to associate" message is sent to node
402 at time period 407. At time period 408 node 402 associates with
node 401. Finally at time period 409, node 403 tries to join the
network again, and associates with node 402.
[0018] FIG. 5 is a block diagram of node 500. In a preferred
embodiment of the present invention node 500 comprises antenna 503
coupled to transmitter/receiver (transceiver) 504, in turn, coupled
to logic circuitry 505. Although various forms for antenna 503,
transceiver 504, and logic circuitry 505 are envisioned, in a
preferred embodiment of the present invention node 500 is formed
from a Freescale Inc. MC13192 transceiver 504 coupled to a Motorola
HC08 8-bit processor 505. When node 500 wishes to communicate with
any other network node, it does so via over-the-air communication
signal 506. Node 500 may serve as a routing or non-routing node.
Additionally, when acting as a routing node, node 500 may serve to
relay data among network nodes.
[0019] FIG. 6 is a flow chart showing operation of the node 500
when acting as a routing node. The logic flow begins at step 601
where transceiver 504 receives an association message (e.g.,
802.15.4 Association Message) from a requesting node. The
association message is a request from the requesting node to form a
communication link (e.g., an ad-hoc communication link) with node
500. As discussed, the request is received via an over-the-air
communication. At step 603, logic circuitry 505 determines if a
maximum number of links has been obtained, and if not, the logic
flow continues to step 613 where a link is established to the
requesting node. If, however, at step 603 it is determined that the
maximum number of links exist for node 500, the logic flow
continues to step 605 where logic circuitry 505 determines if the
requesting node is capable of routing. This determination is
accomplished by analyzing capability information received with the
association message. If, at step 605 it is determined that the
requesting node is not capable of routing, the logic flow ends at
step 615. However, if at step 605 it is determined that the
requesting node is capable of routing, the logic flow continues to
step 607 where logic circuitry 505 determines if any associated
node is a non-routing node. If, at step 607 it is determined that
there exists no non-routing node associated with node 500, the
logic flow ends at step 615, otherwise the logic flow continues to
step 609.
[0020] At step 609 logic circuitry 505 instructs transmitter 504 to
transmit a disassociation message to the associated non-routing
node, resulting in the non-routing node to disassociate (break
communication) with node 500. Next, at step 611, logic circuitry
instructs transmitter 504 to transmit an association message to the
requesting node, causing the requesting node to form a
communication link with node 500.
[0021] While the invention has been particularly shown and
described with reference to a particular embodiment, it will be
understood by those skilled in the art that various changes in form
and details may be made therein without departing from the spirit
and scope of the invention. For example, it is possible that when a
routing capable node attempts to join the network and there are no
association slots available, the routing capable node will first
scan for a potential routing node and any non-routing nodes. If a
non-routing node is found and the node which it is associated with
is also found then the requesting node can directly request the
non-routing node to leave the current association and join the
requesting node after the requesting node takes the non-routing
nodes association slot. The benefit of this is to insure that the
non-routing node can rejoin the network and the requesting node
will not have to query for multiple nodes to associate with. It is
intended that such changes come within the scope of the following
claims.
* * * * *