Topology control in a sensor network balances load on nodes and increases scalability lifetime. Clustering is an effective topology approach. We propose novel distributed clustering approach for long-lived ad hoc networks. Our proposed does not make any assumptions about the presence of infrastructure or node capabilities, other than availability multiple power levels nodes. present protocol, HEED (Hybrid Energy-Efficient Distributed clustering), that periodically selects cluster heads...

Prolonged network lifetime, scalability, and load balancing are important requirements for many ad-hoc sensor applications. Clustering nodes is an effective technique achieving these goals. In this work, we propose a new energy-efficient approach clustering in networks. Based on approach, present protocol, HEED (hybrid distributed clustering), that periodically selects cluster heads according to hybrid of their residual energy secondary parameter, such as node proximity its neighbors or...

The large-scale deployment of wireless sensor networks (WSNs) and the need for data aggregation necessitate efficient organization network topology purpose balancing load prolonging lifetime. Clustering has proven to be an effective approach organizing into a connected hierarchy. In this article, we highlight challenges in clustering WSN, discuss design rationale different approaches, classify proposed approaches based on their objectives principles. We further several key issues that affect...

Cognitive radio (CR) is the key enabling technology for an efficient dynamic spectrum access. It aims at exploiting underutilized licensed by opportunistic communications unlicensed users. In this work, we first develop a distributed cognitive MAC (COMAC) protocol that enables users to dynamically utilize while limiting interference on primary (PR) The main novelty in COMAC lies not assuming predefined CR-to-PR power mask and requiring active coordination with PR provides statistical...

The cognitive radio (CR) paradigm calls for open spectrum access according to a predetermined etiquette. Under this paradigm, CR nodes the opportunistically by continuously monitoring operating channels. A key challenge in domain is how network (CRN) cooperate medium order maximize CRN throughput. Typical multichannel MAC protocols assume that frequency channels are adjacent and there no constraints on transmission power. However, may operate over wide range of frequencies, power mask often...

Organizing sensor nodes into a clustered architecture is an effective method for load balancing and prolonging the network lifetime. However, serious drawback of clustering approach imposed energy overhead caused by "global" operations in every round global round-based policy (GRBP). To mitigate this problem, paper proposes hierarchical clustering-task scheduling (HCSP), which triggers node-driven as opposed to GRBP's time-driven clustering. Based on HCSP, each cluster reconfigured only once...

Novel routing paradigms based on policies, quality of service (QoS) requirements, and packet content have been proposed for the Internet over last decade. Constraint-based algorithms select a path satisfying constraints that are either administrative-oriented (policy routing) or service-oriented (QoS routing). The routes, in addition to constraints, selected reduce costs, balance network load, increase security. In this article, we discuss several constraint-based approaches explain their...

Employing multi-input multi-output (MIMO) links can improve energy efficiency in wireless sensor networks (WSNs). Although a node is likely to be equipped with only one antenna, it possible group several sensors form virtual MIMO link. Such grouping formed by means of clustering. In this paper, we propose distributed MIMO-adaptive energy-efficient clustering/routing scheme, coined cooperative (CMIMO), which aims at reducing consumption multi- hop WSNs. CMIMO, each cluster has up two heads...

Traffic lights (TLs) are used to control traffic at road intersections. Typically, the TL mechanism on operates according a fixed periodic schedule change light (red/yellow/green). A different may be employed late night or early morning hours. Such does not react changing conditions, and is unaware of (unresponsive to) congestion. In this paper, we propose novel framework dynamic (DTLC) DTLC relies sensor network collect data includes protocols handle congestion facilitate more efficient...

Several sensor network applications, such as environmental monitoring, require data aggregation to an observer. For this purpose, a tree, rooted at the observer, is constructed in network. Node clustering can be employed further balance load among nodes and prolong lifetime. In paper, we design implement system, iHEED, which node integrated with multi-hop routing for TinyOS. We consider simple operators, AVG or MAX. use energy consumption model keep track of battery cluster heads regular...

Colored trees (CTs) is an efficient approach to route packets along link- or node-disjoint paths in packet-switched networks. In this approach, two trees, namely red and blue, are constructed rooted at a drain such that the path from any node node-disjoint. For applications where both used simultaneously, it critical maintain after link failures. To end, paper develops algorithm, referred as SimCT, efficiently constructs maintains colored under failures using only local information. Even...

For mobile ad hoc networks used in network-centric operations, there is a growing need for systematic methodology analyzing/predicting the performance of network over mission duration. With advance cognitive networking as possible means exploiting unused spectrum, now to study how design using an automated methodology. In this article we concepts and challenges automatic design/ reconfiguration MANETs. We describe objectives, imposed constraints, involved parameters techniques can be...

Node clustering in sensor networks increases scalability, robustness, and energy-efficiency. In hostile environments, unexpected failures or attacks on cluster heads (through which communication takes place) may partition the network degrade application performance. We propose REED (Robust Energy-Efficient Distributed clustering), for sensors deployed environments an interleaved manner with low complexity. Our primary objective is to construct a k-fault-tolerant (i.e., k-connected) clustered...

The scarcity of unlicensed spectrum has triggered great interest in cognitive radio (CR) technology as a means to improve utilization. An important challenge this domain is how enable nodes CR network (CRN) access the medium opportunistically. Multi-channel MAC protocols for typical ad hoc networks assume that frequency channels are adjacent and there no strict constraints on transmission power. However, CRN may occupy wide range frequencies. In addition, power mask often enforced user avoid...

The conservative nature of the 802.11 ad hoc scheme has instigated extensive research whose goal is to improve spatial reuse and/or energy consumption this scheme. Transmission power control (TPC) was shown be effective in achieving goal. Despite their demonstrated performance gains, previously proposed power-controlled channel access protocols often incur extra hardware cost (e.g., multiple transceivers). Furthermore, they do not fully exploit potential due heuristic allocation and...

Clustering sensor nodes increases the scalability and energy efficiency of communications among them. In hostile environments, unexpected failures or attacks on cluster heads (through which communication takes place) may partition network degrade application performance. this work, we propose a new approach, REED (Robust Energy Efficient Distributed clustering), for clustering sensors deployed in environments. Our primary objective is to construct k (i.e., k-connected) network, where...

Mobile ad hoc networks have become the basis of military's network-centric warfare (NCW) approach. However, for NCW to be successful, it is imperative that designed in a robust manner with capability produce consistent predictable results despite uncertainties underlying environment. This underscores need formal systematic methodologies design and predict performance such networks. The challenges mobile networking combined those associated stringent requirements posed by systems, however,...

We design and implement an efficient on-line approach, FlowMate, for clustering flows (connections) emanating from a busy server, according to shared bottlenecks. Clusters can be periodically input load balancing, congestion coordination, aggregation, admission control, or pricing modules. FlowMate uses in-band (passive) end-to-end delay measurements infer Delay information is piggybacked on feedback the receivers, or, if impossible, TCP application round-trip time estimates are used....

When sensors are redundantly deployed, a subset of senors should be selected to actively monitor the field (referred as "cover"), while rest put sleep conserve their batteries. We consider networks in which all nodes not aware locations or relative directions neighbors. develop several geometric and density-based tests for deciding whether sensor turn itself off without degrading quality coverage. These rely on estimated neighbor distances locally advertised two-hop neighborhood information....

Unlike commercial MANET applications, tactical networks are typically hierarchical and involve heterogeneous types of radio communications. Future also require cognitive functions across the protocol stack to exploit scarce spectrum dynamically adapt configuration settings. In this work we highlight need for novel design tools networks. We define a system model that will provide foundation generic network problem formulations via use techniques covering both dynamic frequency adaptations...

Traffic control at road intersections is based on traffic lights (TLs). The mechanism typically used for operates a periodic schedule to change the light (red/yellow/green). In many cases, different in late night/early morning hours. This fixed does not adequately account changing conditions, and unaware of/unresponsive congestion. this work, we propose framework dynamic intersections. relies simple sensor network collect data includes novel protocols flow handle congestion facilitate flow....