Abstract: Network formation in wireless networks according to an embodiment of the present invention is enhanced based on control of network formation packet transmissions (e.g., Packet Radio Organizational Packet (PROP) transmissions). A source-initiated approach controls re-transmission of inquiry/reply PROP packets based on the presence of a neighboring node. This reduces the size and amount of PROP packets transmitted during neighbor discovery. In addition, the source-initiated approach controls re-transmission of PROP packets indicating a change in an upstream or control type node (e.g., LNC PROP). In this case, the node determines the presence of steady-state conditions (e.g., maintenance of conditions for the original LNC PROP transmission), and enables a single re-transmission of the LNC PROP packet, thereby reducing the transmission of unnecessary or duplicate LNC PROP packets (e.g., containing substantially the same information as previously transmitted packets since conditions have remained the same).

Abstract: A method for broadcasting messages in an ad hoc wireless network having a tree-based architecture is provided. When a node receives a broadcast message for re-broadcasting to other nodes in the network, it builds a list of identifiers of other nodes in the network from which the node requires reception of a broadcast message as an implicit acknowledgment that said other nodes in the network have received said broadcast message. The node builds this implicit acknowledgment list based on stored data pertaining to an existing tree-based topology of the network. After this list is built, the node re-broadcasts the broadcast message. Each node in the network executes this broadcasting protocol and in so doing a broadcast message quickly and efficiently propagates through the network with minimal redundancy and impact on the topology of the network.

Abstract: Network formation in wireless networks according to an embodiment of the present invention is enhanced based on control of network formation packet transmissions (e.g., Packet Radio Organizational Packet (PROP) transmissions). A source-initiated approach controls re-transmission of inquiry/reply PROP packets based on the presence of a neighboring node. This reduces the size and amount of PROP packets transmitted during neighbor discovery. In addition, the source-initiated approach controls re-transmission of PROP packets indicating a change in an upstream or control type node (e.g., LNC PROP). In this case, the node determines the presence of steady-state conditions (e.g., maintenance of conditions for the original LNC PROP transmission), and enables a single re-transmission of the LNC PROP packet, thereby reducing the transmission of unnecessary or duplicate LNC PROP packets (e.g., containing substantially the same information as previously transmitted packets since conditions have remained the same).

Abstract: A node model of the present invention is employed by a network modeling and simulation system and includes a communication protocol stack with a plurality of protocol layers. Each protocol layer includes communication functions. The protocol layer functions are each represented by one or more distinct software implementations that are optimized for different simulation purposes. A configurable module switch is disposed between protocol layers within the stack to selectively control information flow between functions within adjacent protocol layers. The node model enables a user to perform network simulation or analysis of varying detail or granularity.

Abstract: A node with local GPS time in an ad-hoc wireless network synchronizes with the network time immediately and slowly pulls the network time to GPS time. However, network nodes may immediately transition to the common GPS time after an island or group head node determines that the transition in network time does not disturb the communication links.

Abstract: A node with local GPS time in an ad-hoc wireless network synchronizes with the network time immediately and slowly pulls the network time to GPS time. However, network nodes may immediately transition to the common GPS time after an island or group head node determines that the transition in network time does not disturb the communication links.

Abstract: A wireless communications network including multiple nodes, and a local node having GPS-based time for synchronization of time-of-day (TOD) in the network. The network includes at least the local node and a neighbor node communicating in the network. The local node includes a clock generator for generating a local TOD, and a time management unit, coupled to the clock generator, for adjusting the local TOD. A receiver in the local node receives from the neighbor node a message including a neighbor TOD. A counter in the local node computes and provides an integer value corresponding to a number of update values for synchronization of the neighbor TOD to the GPS-based time. A transmitter in the local node transmits to the neighbor node the integer value provided by the counter, whereby the time management unit adjusts the local TOD to the neighbor TOD and then transmits the adjusted local TOD and the integer value to the neighbor node for synchronization of the neighbor TOD to the GPS-based time.

Abstract: The invention includes a method and apparatus for disseminating information in a communication network having a plurality of nodes. The method includes receiving, in a node, a packet including link-state advertisements (LSAs) from the communication network and a flooding status field. Based on the flooding status field, the node determines the type of LSA received and then re-floods the packet onto the communication network, based on the type of LSA determined from the flooding status field. A sub-field in the flooding status field indicates whether the LSA is intended for distribution to the entire communication network, or is intended for distribution to other nodes in the communication network located within a predetermined range of the node. The node prevents re-flooding of the LSA, if the other nodes in the communication network are located outside of the predetermined range. The node includes a re-flood timer which is set to expire based on an urgency level included in the flooding status field.

Abstract: A node model of the present invention is employed by a network modeling and simulation system and includes a communication protocol stack with a plurality of protocol layers. Each protocol layer includes communication functions. The protocol layer functions are each represented by one or more distinct software implementations that are optimized for different simulation purposes. A configurable module switch is disposed between protocol layers within the stack to selectively control information flow between functions within adjacent protocol layers. The node model enables a user to perform network simulation or analysis of varying detail or granularity.

Abstract: An “on-demand” approach for a routing protocol for a wireless network that achieves balanced energy consumption among all participating nodes in the network. Synchronization messages transmitted by nodes associated with an upstream node include local node information (LNI) that a node can use to repair or bypass a lost upstream node in a real or virtual (temporary) manner depending upon the local node's battery level. Only if a repair process fails will a global re-organization (Re-Org) be initiated. The LNI also allows for nodes having lower power availability (battery level) not to transmit the LNI so that unaffiliated node(s) can select an upstream node having more power availability thereby extending network life.

Abstract: An energy efficient MAC protocol for a sensor network that extends the battery life of remotely located wireless nodes by employing MAC operations involving transmission of a wake-up signal with more processing gain, dynamic adjustment of a transmission rate of synchronization messages for fast time synchronization and an energy efficient neighboring node discovery technique.

Abstract: The invention includes a method and apparatus for disseminating information in a communication network having a plurality of nodes. The method includes receiving, in a node, a packet including link-state advertisements (LSAs) from the communication network and a flooding status field. Based on the flooding status field, the node determines the type of LSA received and then re-floods the packet onto the communication network, based on the type of LSA determined from the flooding status field. A sub-field in the flooding status field indicates whether the LSA is intended for distribution to the entire communication network, or is intended for distribution to other nodes in the communication network located within a predetermined range of the node. The node prevents re-flooding of the LSA, if the other nodes in the communication network are located outside of the predetermined range. The node includes a re-flood timer which is set to expire based on an urgency level included in the flooding status field.

Abstract: A wireless communications network including multiple nodes, and a local node having GPS-based time for synchronization of time-of-day (TOD) in the network. The network includes at least the local node and a neighbor node communicating in the network. The local node includes a clock generator for generating a local TOD, and a time management unit, coupled to the clock generator, for adjusting the local TOD. A receiver in the local node receives from the neighbor node a message including a neighbor TOD. A counter in the local node computes and provides an integer value corresponding to a number of update values for synchronization of the neighbor TOD to the GPS-based time. A transmitter in the local node transmits to the neighbor node the integer value provided by the counter, whereby the time management unit adjusts the local TOD to the neighbor TOD and then transmits the adjusted local TOD and the integer value to the neighbor node for synchronization of the neighbor TOD to the GPS-based time.