We present a suite of algorithms for self-organization of wireless sensor networks in which there is a scalably large number of mainly static nodes with highly constrained energy resources. The protocols further support slow mobility by a subset of the nodes, energy-efficient routing, and formation of ad hoc subnetworks for carrying out cooperative signal processing functions among a set of the nodes.

http://mae.engr.ucdavis.edu/dsouza/Protocolsforself-orgWSN.pdf

Protocols for self-organization of a wireless sensor network

Even though multiple non-overlapped channels exist in the 2.4 GHz and 5 GHz spectrum, most IEEE 802.11-based multi-hop ad hoc networks today use only a single channel. As a result, these networks rarely can fully exploit the aggregate bandwidth available in the radio spectrum provisioned by the standards. This prevents them from being used as an ISP's wireless last-mile access network or as a wireless enterprise backbone network. In this paper, we propose a multi-channel wireless mesh network (WMN) architecture (called Hyacinth) that equips each mesh network node with multiple 802.11 network interface cards (NICs). The central design issues of this multi-channel WMN architecture are channel assignment and routing. We show that intelligent channel assignment is critical to Hyacinth's performance, present distributed algorithms that utilize only local traffic load information to dynamically assign channels and to route packets, and compare their performance against a centralized algorithm that performs the same functions. Through an extensive simulation study, we show that even with just 2 NICs on each node, it is possible to improve the network throughput by a factor of 6 to 7 when compared with the conventional single-channel ad hoc network architecture. We also describe and evaluate a 9-node Hyacinth prototype that Is built using commodity PCs each equipped with two 802.11a NICs.

/pdf/architecture-and-algorithms-for-an-ieee-802-11-based-multi-2ha0rzhjbz.pdf

Architecture and algorithms for an IEEE 802.11-based multi-channel wireless mesh network

The present invention is generally directed to a system for monitoring a variety of environmental and/or other conditions within a defined remotely located region. In one aspect, a system is configured to monitor utility meters (613) in a defined area. The system is implemented by using a plurality of wireless transmitters (614), each integrated into a sensor (612) adapted to monitor a particular data input. The system also includes a plurality of transceivers (221) that are dispersed throughout the region at defined locations. The system uses a local gateway (210) to translate and transfer information from the transmitters to a dedicated computer (260) on a network (230). The dedicated computer collects, compiles and stores the data for retrieval upon client demand across the network. The computer further includes means for evaluating the received information and identifying an appropriate control signal to be applied at a designated actuator.

System and method for monitoring and controlling remote devices

The Transmission Control Protocol.

The IEEE 802.11 Wireless LAN standards allow multiple non-overlapping frequency channels to be used simultaneously to increase the aggregate bandwidth available to end-users. Such bandwidth aggregation capability is routinely used in infrastructure mode operation, where the traffic to and from wireless nodes is distributed among multiple interfaces of an access point or among multiple access points to balance the traffic load. However, bandwidth aggregation is rarely used in the context of multi-hop 802.11-based LANs that operate in the ad hoc mode. Most past research efforts that attempt to exploit multiple radio channels require modifications to the MAC protocol and therefore do not work with commodity 802.11 interface hardware. In this paper, we propose and evaluate one of the first multi-channel multi-hop wireless ad-hoc network architectures that can be built using standard 802.11 hardware by equipping each node with multiple network interface cards (NICs) operating on different channels. We focus our attention on wireless mesh networks that serve as the backbone for relaying end-user traffic from wireless access points to the wired network. The idea of exploiting multiple channels is particularly appealing in wireless mesh networks because of their high capacity requirements to support backbone traffic. To reap the full performance potential of this architecture, we develop a set of centralized channel assignment, bandwidth allocation, and routing algorithms for multi-channel wireless mesh networks. A detailed performance evaluation shows that with intelligent channel and bandwidth assignment, equipping every wireless mesh network node with just 2 NICs operating on different channels can increase the total network goodput by a factor of up to 8 compared with the conventional single-channel ad hoc network architecture.

Centralized channel assignment and routing algorithms for multi-channel wireless mesh networks

We consider a large population of mobile stations that are interconnected by a multihop wireless network. The applications of this wireless infrastructure range from ad hoc networking (e.g., collaborative, distributed computing) to disaster recovery (e.g., fire, flood, earthquake), law enforcement (e.g., crowd control, search-and-rescue), and military (automated battlefield). Key characteristics of this system are the large number of users, their mobility, and the need to operate without the support of a fixed (wired or wireless) infrastructure. The last feature sets this system apart from existing cellular systems and in fact makes its design much more challenging. In this environment, we investigate routing strategies that scale well to large populations and can handle mobility. In addition, we address the need to support multimedia communications, with low latency requirements for interactive traffic and quality-of-service (QoS) support for real-time streams (voice/video). In the wireless routing area, several schemes have already been proposed and implemented (e.g., hierarchical routing, on-demand routing, etc.). We introduce two new schemes-fisheye state routing (FSR) and hierarchical state routing (HSR)-which offer some competitive advantages over the existing schemes. We compare the performance of existing and proposed schemes via simulation.

/pdf/scalable-routing-strategies-for-ad-hoc-wireless-networks-42km53netx.pdf

Scalable routing strategies for ad hoc wireless networks

In a connection-oriented network where ATM nodes are interconnected by links, periodically updated link status information of the network is stored in a database to indicate resource constraints of the network links Responsive to a connection request specifying multiple QOS parameters, a first path to a destination is selected and a first signaling message is transmitted containing routing data of the first path toward the destination if resource constraints of the first path satisfy all the specified QOS parameters If the transmission of the first signaling message is unsuccessful or the resource constraints of the first path do not satisfy all the specified QOS parameters, then a second path to the destination is selected according to contents of the database that correspond to one of the specified QOS parameters, and a second signaling message containing routing data of the second path is transmitted toward the destination

Source routing for connection-oriented network with repeated call attempts for satisfying user-specified QOS parameters

Setting of a bypass path upon occurrence of transmission failure, is applicable for large scale network. A system includes signaling means which makes judgment whether bypassing process is performed by an own node by a bypassing process judgement means when a release message issued upon occurrence of failure, is received. Upon judgment to perform bypassing process, computation of bypass path is requested by the path computing means. On the basis of result of computation, bypass path is established and switched. In the bypassing process judgment means, judgment is made whether bypassing process is performed by the signaling means or not depending upon the relationship of positions of the faulty portion and the own node.

Fault recovery system and transmission path autonomic switching system

In a hierarchical network, an aggregation parameter is exchanged between a node and its neighbor to agree on a negotiated parameter. A set of physical links between them are aggregated into a logical link according to the negotiated parameter and resource data of the logical link is stored in a database of each node. The resource data is then exchanged between them and the contents of the database of each node are updated with resource data of its neighbor. To optimize the link aggregation, an operating performance of the logical link is evaluated by the node using traffic data from the network, and the negotiated parameter is updated according to the detected operating performance. The updated aggregation parameter of the node is exchanged with its neighbor to agree on a negotiated updated parameter which is used to aggregate the physical links into the logical link.

Topology aggregation using parameter obtained by internodal negotiation

In a failure restoration system comprising a distributed hierarchical routing section which is adapted to set up a main path and previously determine an alternate path for the main path in a network, an alternate path selection section is adapted to obtain complete source route information for the main path when it attempts to set up the main path. The alternate path selection section adds the complete source information to a SETUP signaling message for setting up the alternate path, thereby provides a physical alternate path as much different as possible from the main path.

Atsushi Iwata

Papers

Scalable routing strategies for ad hoc wireless networks

Source routing for connection-oriented network with repeated call attempts for satisfying user-specified QOS parameters

Fault recovery system and transmission path autonomic switching system

Topology aggregation using parameter obtained by internodal negotiation

Failure restoration system suitable for a large-scale network