Rolando Menchaca-Mendez

PRIME: an interest-driven approach to integrated unicast and multicast routing in MANETs

A framework for integrated multicast and unicast routing in mobile ad hoc networks (MANETs) is introduced. It is based on interest-defined mesh enclaves that are connected components of a MANET spanning the sources and receivers of unicast or multicast flows. The Protocol for Routing in Interest-defined Mesh Enclaves (PRIME) is presented to implement the proposed framework for integrated routing in MANETs. PRIME establishes meshes that are activated and deactivated by the presence or absence of interest in individual destination nodes and groups and confines most of the signaling overhead within regions of interest (enclaves) in such meshes. The routes established in PRIME are shown to be free of permanent loops. Experimental results based on extensive simulations show that PRIME attains similar or better data delivery and end-to-end delays than traditional unicast and multicast routing schemes for MANETs (AODV, OLSR, ODMRP). The experiments also show that signaling in PRIME is far more scalable than the one used by traditional multicast and unicast routing protocols such as AODV, OLSR, or ODMRP.

GEONTO-MET: an approach to conceptualizing the geographic domain

To date, there are different ontologies for many domains and applications. Users can access them to share information, reuse knowledge, and integrate data sources for several purposes and applications such as semantic web, data warehousing, e-learning, e-commerce, knowledge representation, and so on. Ontology engineering is rapidly becoming a mature discipline, having produced tools and methodologies for building and managing ontologies. However, even with a clearly defined engineering methodology, building an ontology remains a challenging, time-consuming, and error-prone task, because it forces ontology builders to conceptualize their expert knowledge explicitly and to re-organize it in typical ontological categories such as concepts, properties, and axioms. In this article, an approach to conceptualizing the geographic domain is described. It is oriented toward formalizing a geographic domain conceptualization according to specifications from the Mexican Institute of Statistics, Geography and Informatics. The main goal is to provide semantic and ontological descriptions, which represent the properties and relationships that describe the behavior of geographic objects by means of concepts. GEONTO-MET is focused on developing geographic application ontologies for sharing and integrating geospatial information.

Opportunistic Interaction in P2P Ubiquitous Environments

In this paper we present the design and implementation of an ubiquitous system that supports the opportunistic collaborative edition of shared documents. Our system is based on the instant messaging metaphor in the sense that it uses concepts and interfaces similar to those used in instant messaging systems. We employ the concept of group to define a cluster of users that work on a particular shared document and use awareness to convey the state of users with respect to the shared documents (editing, reading, not using it). The system is implemented using a peer-to-peer (P2P) architecture and can be accessed by means of mobile devices such as handheld computers or cellular phones as well as from desktop computers. The P2P architecture provides the system with useful properties such as fault tolerance, the possibility of using public key infrastructures to implement secure transactions, scalability, a P2P repository to store shared documents and a distributed awareness service.

Robust and Scalable Integrated Routing in MANETs Using Context-Aware Ordered Meshes

A new context-aware routing framework for multicast and unicast routing in mobile ad hoc networks is introduced. This framework, which is called CAROM (Context-Aware Routing over Ordered Meshes), uses regions of interest to identify connected componnets of the network that span sources and destinations of interest to restrict signaling to occur mostly within these regions. Context information is used to compute routing meshes composed of shortest-paths located inside of regions of interest. Experimental results based on extensive simulations show that CAROM attains similar or better data delivery and end-to-end delays than traditional unicast and multicast routing schemes for MANETs (AODV, OLSR, ODMRP), and that CAROM incurs only a fraction of the signaling overhead of traditional routing schemes.

SCORPION: a heterogeneous wireless networking testbed

During the last decade, the success and popularity of wireless standards such as IEEE 802.11 have drawn the attention of the research community to wireless networks. A great amount of effort has been invested into research in this area, most of which relies heavily on simulation and analysis techniques. However, simulations do not precisely control hardware interrupts, packet timing and real physical and MAC layer behaviors. As a result, simulation results need to be validated by real implementations, which is evident by the change in focus of research activities increasingly moving towards real implementations, including the deployment of testbeds as a main tool to analyze network protocol functionality. Under this context, we present an overview of SCORPION (Santa Cruz mObile Radio Platform for Indoor and Outdoor Networks), a heterogeneous wireless networking testbed that includes a variety of nodes ranging from ground vehicles to autonomous aerial vehicles. The purpose of SCORPION to is to deploy and investigate nascent networking protocols using a variety of mobile platforms utilizing structured as well as unstructured mobility patterns.

Fast track article: Hydra: Efficient multicast routing in MANETs using sender-initiated multicast meshes

We present Hydra, the first multicast routing protocol for MANETs that establishes a multicast routing structure approximating the set of source-rooted shortest-path trees from multicast sources to receivers, without requiring the dissemination of control packets from each source of a multicast group. Hydra accomplishes this by dynamically electing a core for the mesh of a multicast group among the sources of the group, and aggregating multicast routing state in the nodes participating in multicast meshes, so that only control packets from the core are disseminated towards the receivers of a group. We prove that Hydra establishes correct routes from senders to receivers of a multicast group when multicast state information is aggregated. We also present simulation results illustrating that Hydra attains comparable or higher delivery ratios than the On-Demand Multicast Routing Protocol (ODMRP), but with considerably lower end-to-end delays and far less communication overhead. Results are shown for scenarios using 802.11 DCF and TDMA as the MAC layer protocols and using random waypoint and group mobility as mobility models.

DPUMA: a highly efficient multicast routing protocol for mobile ad hoc networks

In this paper we present DPUMA, a mesh-based multicast routing protocol specifically designed to reduce the overhead needed to deliver multicast packets, saving bandwidth and energy, two of the scarcest resources in MANETS. The two main features of DPUMA are: (1) for each multicast group, it periodically floods a single control packet to build the mesh, elect the core of the mesh and get two-hop neighborhood information; and (2), it computes the mesh’s k-dominating set to further reduce overhead induced by flooding the mesh when forwarding data packets. These two characteristics contrast with other protocols that blindly flood the net in different stages to construct their routing structure (mesh or tree), to elect the leader of the structure, and that exchange hello messages to get neighborhood information. Using detailed simulations, we show over different scenarios that our protocol achieves similar or better reliability while inducing less packet transmission overhead than ODMRP, MAODV and PUMA which is DPUMA’s predecessor.

Scalable multicast routing in MANETs using sender-initiated multicast meshes

We present Hydra, the first multicast routing protocol for MANETs that establishes a multicast routing structure approximating the set of source-rooted shortest-path trees from multicast sources to receivers, without requiring the dissemination of control packets from each source of a multicast group. Hydra accomplishes this by dynamically electing a core for the mesh of a multicast group among the sources of the group, and aggregating multicast routing state in the nodes participating in multicast meshes, so that only control packets from the core are disseminated towards the receivers of a group. We prove that Hydra establishes correct routes from senders to receivers of a multicast group when multicast state information is aggregated. We also present simulations results illustrating that Hydra attains comparable or higher delivery ratios than ODMRP, but with considerably lower end-to-end delays and far less communication overhead. Results are shown for scenarios using 802.11 and TDMA as the MAC layer protocols.

An interest-driven approach to integrated unicast and multicast routing in MANETs

This paper introduces an integrated framework for multicast and unicast routing in mobile ad hoc networks (MANET) based on interest-defined mesh enclaves. Such meshes are connected components of a MANET that span the sources and receivers of unicast and multicast flows. We present the Protocol for Routing in Interest-defined Mesh Enclaves (PRIME), which establishes meshes that are activated and deactivated by the presence or absence of interest in destinations and groups, and which confines most of the signaling overhead within regions of interest (enclaves) in such meshes. Experimental results based on simulations show that PRIME attains similar or better data delivery and end-to-end delays than traditional unicast and multicast routing schemes for MANETs (AODV, OLSR, ODMRP), and that PRIME incurs only a fraction of the signaling overhead of traditional routing schemes.

Performance Analysis of Cluster Formation in Wireless Sensor Networks

Clustered-based wireless sensor networks have been extensively used in the literature in order to achieve considerable energy consumption reductions. However, two aspects of such systems have been largely overlooked. Namely, the transmission probability used during the cluster formation phase and the way in which cluster heads are selected. Both of these issues have an important impact on the performance of the system. For the former, it is common to consider that sensor nodes in a clustered-based Wireless Sensor Network (WSN) use a fixed transmission probability to send control data in order to build the clusters. However, due to the highly variable conditions experienced by these networks, a fixed transmission probability may lead to extra energy consumption. In view of this, three different transmission probability strategies are studied: optimal, fixed and adaptive. In this context, we also investigate cluster head selection schemes, specifically, we consider two intelligent schemes based on the fuzzy C-means and k-medoids algorithms and a random selection with no intelligence. We show that the use of intelligent schemes greatly improves the performance of the system, but their use entails higher complexity and selection delay. The main performance metrics considered in this work are energy consumption, successful transmission probability and cluster formation latency. As an additional feature of this work, we study the effect of errors in the wireless channel and the impact on the performance of the system under the different transmission probability schemes.