Multiplex communications – Network configuration determination – Using a particular learning algorithm or technique
Reexamination Certificate
1999-12-06
2004-03-09
Nguyen, Chau (Department: 2633)
Multiplex communications
Network configuration determination
Using a particular learning algorithm or technique
C370S351000, C370S400000
Reexamination Certificate
active
06704293
ABSTRACT:
BACKGROUND
The present invention relates to ad-hoc networks. More particularly, the present invention relates to routing in ad-hoc networks.
Conventional networking protocols are based on the characteristics and/or features of fixed networks. In fixed networks, the network configuration typically does not change. Although nodes can be added and removed in fixed networks, the route traveled by data packets between two nodes typically does not change. The disadvantage is that fixed networks cannot be easily reconfigured to account for increases in data traffic, also called system loading. Accordingly, when system loading increases for one node, the surrounding nodes are likely to experience increased delays in the transmission and reception of data.
In contrast to fixed networks, ad-hoc networks are dynamic. An ad-hoc network is formed when a number of nodes decide to join together to form a network. Since nodes in ad-hoc networks operate as both hosts and routers, ad-hoc networks do not require the infrastructure required by fixed networks. Accordingly, ad-hoc networking protocols are based upon the assumption that nodes may not always be located at the same physical location.
Bluetooth is an exemplary ad-hoc networking technology. Bluetooth is an open specification for wireless communication of both voice and data. It is based on a short-range, universal radio link, and it provides a mechanism to form small ad-hoc groupings of connected devices, without a fixed network infrastructure, including such devices as printers, PDAs, desktop computers, FAX machines, keyboards, joysticks, telephones or virtually any digital device. Bluetooth operates in the unlicenced 2.4 GHz Industrial-Scientific-Medical (ISM) band.
FIG. 1
illustrates a Bluetooth piconet. A piconet is a collection of digital devices, such as any of those mentioned above, connected using Bluetooth technology in an ad-hoc fashion. A piconet is initially formed with two connected devices, herein referred to as Bluetooth devices. A piconet can include up to eight Bluetooth devices. In each piconet, for example piconet
100
, there exists one master Bluetooth unit and one or more slave Bluetooth units. In
FIG. 1
Bluetooth unit
101
is a master unit and unit
102
is a Bluetooth slave unit.
According to Bluetooth technology a slave unit can only communicate directly with a master unit.
FIG. 2
illustrates a piconet with a master unit
201
and a plurality of slave units
202
-
208
arranged in a star network topology. If slave unit
202
wishes to communicate with slave unit
206
, slave unit
202
would have to transmit the information it wished to communicate to master unit
201
. Master unit
201
would then transmits the information to slave unit
206
.
A scatternet is formed by multiple independent and unsynchronized piconets.
FIG. 3
illustrates an exemplary scatternet
300
. In
FIG. 3
, piconet
1
includes a master node
303
and the slave nodes
301
,
302
and
304
; piconet
2
includes the master node
305
and the slave nodes
304
,
306
,
307
and
308
; and piconet
3
includes the master node
309
and the slave nodes
308
,
310
and
311
. To implement a scatternet it is necessary to use nodes which are members of more than one piconet. Such nodes are herein referred to as forwarding nodes. If, for example, node
301
wishes to communicate with node
310
, then nodes
304
and
308
might act as forwarding nodes by forwarding the connection between the two piconets and in particular between nodes
301
and
310
. For example, node
301
transfers the information to the master node of piconet
1
node
303
. Master node
303
transmits the information to forwarding node
304
. Forwarding node
304
then forwards the information to master node
305
, which in turn, transmits the information to forwarding node
308
. Forwarding node
308
forwards the information to master node
309
which transmits the information to the destination node
310
.
FIG. 4
a
illustrates the protocol layers of two conventional Bluetooth units. As indicated, both units
401
and
402
includes a high level protocol or application
411
. They also include a network layer
421
, a data link layer including a logical link control and adaptation protocol (L2CAP)
441
and link manager protocol (LMP), and the physical layer including a baseband component.
In general, the protocols which govern the formation and/or updating of routes in an ad-hoc network may be classified as either proactive or reactive. Proactive routing protocols attempt to update and maintain routes between nodes, including routes which are not currently in use. Typically, proactive routing protocols react to network topology changes, even if there is no current traffic which is affected by the topology change. To update and maintain the routes between nodes in an ad-hoc network employing proactive routing, each node periodically transmits control information to other nodes in the network. However, this requires a large amount of signaling, which consumes precious bandwidth and leads to network congestion. The network congestion, in turn, results in greater transmission delays for packets traveling through the network.
In contrast to proactive routing protocols, reactive routing protocols establish routes only when there is an immediate need to transmit packets. Moreover, reactive routing protocols only maintain information about routes which are currently being used for transmitting data packets. Accordingly, reactive protocols result in less network signaling, and hence, less network congestion and less delay due to the congestion as compared to proactive routing protocols.
FIG. 5
illustrates conventional routing techniques. In step
505
the source node generates a message. In step
510
the node determines whether the message is a broadcast message or a unicast message. If the message is a broadcast message, in accordance with the “Broadcast” path out of decision step
510
, then the source node broadcasts the packets to its neighbor nodes.
If the message is a unicast message, in accordance with the “Unicast” path out of decision step
510
, then it is determined whether the source node knows a route to the destination node in accordance with step
520
. If a route to the destination node is known, in accordance with the “Yes” path out of decision step
520
, the source node will send the unicast message to the node specified in the source node's routing table in accordance with step
525
.
If a route to the destination node is not known, in accordance with the “No” path out of decision step
520
, then the source node broadcasts a request for route message in accordance with step
530
. In step
535
a neighbor node receives the request for route message. In step
540
the neighbor node determines whether it has already processed the request for route message. The neighbor node makes this determination based upon a source node address and broadcast identifier in the request for route message. If the neighbor node has already processed the request for route message, in accordance with the “Yes” path out of decision step
540
, the node will drop the message in accordance with step
545
.
If the node has not already processed the message, in accordance with the “No” path out of decision step
540
, then the node stores the source node address and broadcast identifier. In step
555
the node rebroadcasts the request for route message to its neighbor nodes. In step
560
the node determines whether it is the destination node. If the node determines that it is not the destination node, in accordance with the “No” path out of decision step
560
, then the node is done with its processing for this message. However, if the node is the destination node, in accordance with the “Yes” path out of decision step
560
, the node will send a response back to the source node in accordance with step
565
. In step
570
the source node sends the unicast message to the destination node over the newly established route. In accordance with reactive routing, the source
Larsson Tony
Rune Johan
Sörensen Johan
Burns Doane , Swecker, Mathis LLP
George Keith M.
Nguyen Chau
Telefonaktiebolaget LM Ericsson (publ)
LandOfFree
Broadcast as a triggering mechanism for route discovery in... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Broadcast as a triggering mechanism for route discovery in..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Broadcast as a triggering mechanism for route discovery in... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3239443