Sara Berri 1,2* , Samson Lasaulce 2 and Mohammed Said Radjef 1
One formal way of studying cooperation and incentive mechanisms in wirelessadhocnetworks is to use game theory. In this respect, simple interaction models such as the forwarder’s dilemma have been proposed and used successfully. However, this type of models is not suited to account for possible fluctuations of the wireless links of the network. Additionally, it does not allow one to study the way a node transmits its own packets. At last, the repeated game models used in the related literature do not allow the important scenario of nodes with partial information (about the link state and nodes actions) to be studied. One of the contributions of the present work is precisely to provide a general approach to integrate all of these aspects. Second, the best performance the nodes can achieve under partial information is fully characterized for a general form of utilities. Third, we derive an equilibrium transmission strategy which allows a node to adapt its transmit power levels and packet forwarding rate to link fluctuations and other node actions. The derived results are illustrated through a detailed numerical analysis for a network model built from a generalized version of the forwarder’s dilemma. The analysis shows in particular that the proposed strategy is able to operate in the presence of channel fluctuations and to perform significantly better than the existing transmission mechanisms (e.g., in terms of consumed network energy).
In this paper, we have proposed a novel multiobjective optimization framework for network routing and resource allocation in wirelessadhocnetworks. Our proposed framework consists of a general probabilistic network model capable of capturing the impact and interaction of a wide range of resource/interference management tech- niques, various channel conditions, and network scenarios. Used in conjunction with metaheuristic optimization tech- niques, this framework provides an efficient tool to capture the trade-offs between different performance metrics and to obtain bounds on the achievable performance of routing for a single source–destination transmission. Results were obtained for characterizing the delay, reliability, and energy trade-offs for a two time slot sensor network model. Future work will extend the model to consider more complex network scenarios, for example accounting for various network topologies, including multiple concurrent flows in the network, and using more refined cross-layer interac- tion and interference models. Other development will introduce a continuous network model in order to get asymptotic Pareto optimal sets for large scale networks. In the same sense, we will target as well networks of mobile nodes by leveraging statistical mobility models of the liter- ature. In this case, links between nodes are a function of their probability to meet with a sufficient channel capacity. Acknowledgments
In Mobile AdhocNETworks (MANET), each node is involved in the process of forwarding packets and maintaining a set of valid routes. As a MANET topology is mobile and the connectivity is unpre- dictable, it is rather challenging to establish and main- tain routing tables. Additional challenges lay in the fact that wireless communications are impacted by stochastic and time-varying phenomena such as fad- ing or interference. Hence, alike wired networks, the behavior of adhocnetworks becomes very complex to predict and the Cross-layer interaction is a new way of managing interactions between layers introduced in previous works [1, 2]. The reader can refer to  for a detailed survey of cross-layer design. In wirelessnetworks there are a large number of phenomena that have an effect on the end-to-end performance. A layered architecture like the seven layers of the OSI model has divided each networking task into the services provided by one layer. This architecture en- ables each layer to communicate directly only with an
In order to evaluate the benefits of directional beamforming for realizing small world behavior, we first do a simulation based analysis of the potential benefits and challenges 1 . We consider a setup in which a fraction of nodes use long range beams in randomly chosen directions. Our results show that significant reduction can be achieved in the average path length of the network. However, the path length improvements are accompanied by a high fraction of paths being asymmetric, which results from the directional nature of links , . Algorithm design for small world creation using directional beamforming, therefore, needs to strike a balance between path length reduction and loss in connectivity. Motivated by the benefits achievable using randomized beamforming, we shift our focus to distributed algorithm design for small world creation using directional beamforming. Central to our design is a new measure of centrality defined in this paper that allows distributed estimation of the structural importance of nodes in the network. We define Wireless Flow Betweenness (WFB) which gives an accurate estimate of the Flow Betweenness Centrality (FBC) . The proposed measure enhances the earlier measure defined in  by identifying key redundancies. The key aspect of WFB is that it can be computed in a completely distributed manner by exploiting the wireless broadcast advantage (WBA)  for information regarding traffic flow, thereby incurring negligible overheads. To our knowledge, the only other measure of centrality designed from the perspective of distributed implementation in wirelessadhocnetworks is the Aggregated Weight N-hop Ranking (AWeNoR) proposed by the authors in . However, though it does away with the need for global network information, it still requires explicit multi-hop information.
Small worlds are an attractive model for reorganizing a wirelessadhocnetworks so as to ensure performance guar- antees. As wirelessnetworks typically suffer from issues of connectivity, maintaining high clustering guarantees reliability. Further, wirelessnetworks typically suffer from drops in network performance with increase in network size. Reorga- nization of a network with the path length bounded as the logarithm of the network size ensures scalability. However, due to the spatial nature of wirelessnetworks, links between nodes cannot be randomly rewired as they are constrained by the transmission range. In , Helmy used simulation results to study the behaviour of wirelessnetworks as a result of random addition of distance limited short cuts. Instead of random rewiring or addition of links, deterministic placement of short cuts was studied by  and  in which they consider hybrid sensor networks that include a small set of wired links. Similarly, Guidoni et al. in  proposed using high capacity nodes in a heterogenous sensor network for short cut creation. In this paper, we study how small world behavior can be realized in a wireless network by the use of directional beam forming at nodes. Our primary motivation for using directional antennas stems from the fact that they can be used to transmit over longer transmission ranges than omnidirectional antennas while using the same transmission power. This implies that short cuts can be created between nodes without the need for
Index Terms—Maximum weight scheduling, backlog/delay bounds, capacity region, order optimal delay
I. I NTRODUCTION
Wireless scheduling has been known to be a key problem for throughput/capacity optimization in wirelessnetworks. The well-known maximum weight scheduling algorithm has been proposed by Tassiulas in his seminal paper  where he proved its throughput optimality. Latter developments in this area include extension of this maximum weight scheduling algorithm to wirelessnetworks with rate/power control , , network control when offered trafﬁc is outside the ca- pacity region , and other scheduling policies with lower- complexity -. While most existing works in the area of stochastic network control focused on throughput perfor- mance of optimal and suboptimal scheduling policies, delay properties of most scheduling policies proposed for wirelessadhocnetworks remain unknown. In this paper, we study backlog/delay properties of the maximum weight scheduling algorithm in wirelessadhocnetworks.
Abstract: This study proposes a new modeling approach for wirelessad-hocnetworks. The new
approach is based on the construction of fuzzy neighborhoods and essentially consists of assigning a membership or importance degree to each network radio link which reflects the relative quality of this link. This approach is first used to model the flooding problem and then an algorithm is proposed to solve this problem which is of a great importance in ad-hocwirelessnetworks intrinsically subject to a certain level of node mobility. Simulations carried out in a dynamic environment show promising results and stability compared to the enhanced dominant pruning algorithm. Such an approach is suitable to take into account the volatile aspect of radio links and the physical layer uncertainty when modeling these networks, particularly when the physical layer offers no or insufficient guaranties to high-level protocols as for the flooding.
Achieving security in wirelessadhocnetworks is a complex task due to the nature of the wireless environment and the lack of infrastructure . A number of protocols have been developed to add security to routing in adhocnetworks. Papadimitriou  proposed SRP (Secure Routing Protocol) based on DSR. The protocol assumes the existence of a security association between the source and destination to validate the integrity of a discovered route. Dahill  proposed the ARAN (Authenticated Routing for AdhocNetworks) protocol that uses public key cryptography instead of the shared security association used in the SRP. Each intermediate node running the protocol verifies the integrity of the received message before forwarding it to its neighbor nodes. Source and destination nodes use certificates included in the route discovery and reply messages to authenticate each other. The protocol has an optional second discovery stage that provides non- repudiating route discovery. Yi  developed a generalized SAR (Security-Aware Ad-hoc Routing) protocol for discovering routes that meet a certain security criteria. The protocol requires that all nodes that meet a certain criteria share a common secret key.
In this paper, we propose ES-CMR which is an energy aware and stable clustered-based multipath routing protocol for wirelessadhocnetworks, in order to reduce node energy consumption, end-to-end delay and extend network lifetime. ES-CMR is a cluster-based protocol that improves the performance of adhocnetworks. The proposed protocol is a multipath routing protocol that uses an energy-aware mechanism which exploits the residual energy of nodes and link stability to select the best discovered paths. We conducted simulation experiments to evaluate the performance of our protocol and to demonstrate that it performs significantly better than a well-known protocol proposed in literature such as EACMR. ES-CMR reduces energy consumption by at least 39% compared to EACMR for a network size of 180. ES-CMR outperforms EACMR by extending the node lifetime and has a lower average end-to-end delay, because paths are computed depending on the energy of their nodes and their stable links.
Wirelessadhocnetworks are by definition created on-the-fly to achieve a specific purpose; they operate in a distributed way without relying on existing infrastructure. In the
early 1970’s, adhocnetworks were first designed for battlefield communications. The great
amount of research work done insofar has led to the integration of adhocnetworks for applications in daily life. Communicating in an adhoc fashion brings interesting solutions to guarantee ubiquitous connectivity for the Internet of future; it is exploited in creating smart and self-aware environments. It also provides potentially endless opportunities in a diverse number of applications. Adhoc communications are useful for Intelligent Transportation Systems (ITS), where a network of sensors set up throughout the vehicle can interact with other vehicles and infrastructure around to provide more accurate feedback about the traffic conditions, and the presence or not of danger on the road . Wirelessadhoc communications are also used in eco-system monitoring. A set of devices are deployed to monitor the heat, or the water flows into catchment areas, to provide early warning systems for flood prone regions or earthquake prone areas . The growth of nanotechnologies and short range communication systems such as IEEE 802.15.4  the basis of Zigbee , has given rise to health care applications, where a set of sensors is used for pulse or diabetes monitoring, and for old people assistance as well.
In order to mitigate the limitations of the layered net- work architecture, cross-layer interactions have to be con- sidered in the framework definition. In  , the authors address a cross-layer optimization problem of joint design of routing, Medium Access Control (MAC), and physical layer protocols with cooperative communication to achieve minimum power cost under a specified per-hop packet er- ror rate (PER) objective in wireless sensor networks. The authors in  highlight the need to find ‘‘a simple interface to the physical layer that allows the upper layers to achieve optimal or near optimal cross-layer performance based on the underlying channel conditions’’. For the cross-layer model we describe in the following sections, we define a link probability–the probability a packet arrives over a gi- ven link. This parameter serves as an interface between net- work layer routing/link layer management decisions and expected physical layer performance by leveraging the broadcast nature of wireless transmissions. The variables of our multi-objective optimization problem determine how often and when a node should re-broadcast a received packet. The approach we take in this work provides for the characterization of fundamental upper bounds, the tradeoff space of multiple criteria, and the routing and resource allo- cation decisions to achieve these tradeoffs. This approach mirrors the key research areas proposed in the framework of  . The authors describe the need for joint research in the areas of fundamental performance upper bounds, layer- less dynamic network performance, and application and network optimization. It is through the interaction of these research areas that adhoc network design and performance can be related and formalized.
CoopGeo: A Beaconless Geographic Cross-Layer Protocol for Cooperative WirelessAdHocNetworks
Teck Aguilar, Syue-Ju Syue, Vincent Gauthier, Hossam Afifi and Chin-Liang Wang
Abstract—Cooperative relaying has been proposed as a promising transmission technique that effectively cre- ates spatial diversity through the cooperation among spatially distributed nodes. However, to achieve efficient communications while gaining full benefits from nodes cooperation, more interactions at higher layers of the protocol stack, particularly the MAC (Medium Access Control) and network layers, are indispensably required. This is ignored in most existing articles that mainly focus on physical-layer relaying techniques. In this paper, we propose a novel cross-layer framework involving two levels of joint design—a MAC-network cross-layer design for forwarder selection (also termed routing) and a MAC- physical for relay selection—over symbol-wise varying channels. Based on location knowledge and contention processes, the proposed cross-layer protocol, CoopGeo, aims at providing an efficient, distributed approach to select next hops and optimal relays along a communication path. Simulation results demonstrate that CoopGeo not only operates properly with varying densities of nodes, but also performs significantly better than the existing protocol BOSS in terms of packet error rate, transmission error probability, and saturated throughput.
In this paper, we propose ES-CMR which is an energy aware and stable clustered based multipath routing protocol for wirelessadhocnetworks, in order to reduce nodes energy consumption and end-to-end delay and extend network lifetime. ES-CMR is a cluster based protocol which improves the performance of adhocnetworks. The proposed protocol is a multipath routing protocol which uses an energy-aware mechanism which exploits the residual energy of nodes and link stability to select the best discovered paths. We conducted simulation experiments to measure the performance of our protocol and demonstrate that it performs significantly better than well known protocol proposed in literature such as EWCA. ES-CMR reduces energy consumption by at least 47% compared to EWCA for a network size of 90 to 120, and nearly 39% when the network size is between 150 and 180 on average. ES- CMR outperforms EWCA by extending the node lifetime and has a lower average end-to-end delay, because paths are computed depending on the energy of their nodes, and the best path is selected.
2 Related Work
Dynamic Host Configuration Protocol (DHCP)  is commonly used for dynamic address assignment in traditional networks. Works on dynamic address assignment for adhoc net- work include [11, 15, 12]. Solutions for duplication detection in adhocnetworks has been proposed previously (e.g. [3, 16, 17, 18]). In , each node has an fixed-length identifier which is randomly generated. A special message that includes nodes’ address and identifier is diffused to the entire network; a node detects a duplicate address when it receives a mes- sage that has the same address as its own, but with a different identifier. Global unique or randomly generated keys are assumed in , in which duplication is detected by attaching key information in link state packets. The approach proposed in  successfully prevents packets from being delivered to wrong destinations. Most approaches for duplicate address detection require propagation of key information, which causes high packet overhead. Since lower protocol overhead is one of the most important design goals for wirelessadhoc net- works, works have been done in achieving efficiency in terms of protocol overhead. Protocols proposed in  and  generate almost no protocol overhead: it detects address conflicts in a passive manner based on anomalies in routing protocol traffic. In particular, the idea of detecting duplication by comparing neighborhood information is proposed in approach PDAD-NH  . However, no correctness proof is presented. In our work, we show this approach works in most networks, except a special class of networks; the existence of this class of networks indicates the different ability of wired and wirelessnetworks in duplication detection using neighborhood information.
WirelessAdHocNetworks promise a simple and decentralised way of connecting nodes, without need of coordination or hierarchy. Because the wireless nodes are generally mobile, they usually embed a limited quantity of energy and are considered as energy constrained. Thus, Medium Access Control (MAC) protocols have to minimize activities on medium, i.e. limit not only transmission but also reception activities, because of the complexity of the receiver: on these transceivers, the energy consumption is generally more important in the receive state than in transmit state. Nodes must enter sleep mode regularly, but also being available during common periods negotiated with their 1-hop neighbours. The nodes use the principle of rendez-vous to get this common period.
A wirelessadhoc network comprises either fixed or mobile nodes connected wirelessly without the support of any fixed infrastructure or central administration. The nodes are self- organized and can be deployed “on the fly” anywhere, any time to support a particular purpose. Two nodes can communicate if they are within each other’s transmission range; otherwise, intermediate nodes can serve as relays (routers) (multi-hop routing). These networks have several salient features: rapid deployment, robustness, flexibility, inherent mobility support, highly dynamic network topology (device mobility, changing properties of the wireless channel, i.e. fading, multipath propagation, and partitioning and merging of adhocnetworks are possible), the limited battery power of mobile devices, limited capacity, and asymmetric/unidirectional links. Wirelessadhocnetworks are envisioned to support advanced applications such as military operations (formations of soldiers, tanks, planes), civil applications (e.g. audio and video conferencing, sport events, telematics applications (traffic)), disaster situations (e.g. emergency and rescue operations, national crises, earthquakes, fires, floods), and integration with cellular systems (Perkins, 2000; Toh, 2002). Figure 1.1 demonstrates a typical wirelessadhoc network.
Among the protocols that have been proposed to lessen the problem of energy consump- tion, many are “link-based solutions”, while “node-based solutions” can offer better results. Indeed, in adhocnetworks, mobiles are generally equipped with omni-directional antennas, that is when a mobile emits a message with a given range, every of its neighbors within this range receives the message. This is known as the “Wireless Multicast Advantage” and was described by Wieselthier et al. . They proposed a globalized heuristics known as BIP (Broadcast Incremental Power ) that makes use of this and constructs an efficient broadcast tree from a source mobile to any other one.
Research efforts aiming at merging cellular wireless and adhoc networking have been recently increasing [ 5 , 26 , 6 , 13 , 2 , 23 , 7 ]. Hybrid networks, the extension of cellular network using adhoc connectivity, offer obvious benefits. On one hand, they allow an extension cellular networks range using adhoc connectivity and on the other hand they provide a global Internet connectivity to adhoc nodes. However, deployment of a wired cellular infrastructure still represents a high cost as well as a lot of constraints. Both costs and constraints can be reduced if we replace the wired infrastructure network by a fully wireless one. The infrastructure network becomes a collection of static wireless nodes acting both as base stations and infrastructure routers. Infrastructure communications become wireless multi- hop communications. As the wireless medium really differs from the wired one (pervasive medium, non isolated links, higher latency and lower bandwidth), the design of classical micro-mobility protocols must be rethought and if necessary altered. As it seems hard to achieve as good performances in a wireless hybrid network as in a wired one, a deeper attention must be given to each layer of the networking stack in order to design protocols in adequation with the wireless medium characteristics.
Building an eﬃcient node localization system in wireless sensor networks is facing several chal- lenges. For example, calculating the square root consumes computational resources and utilizing ﬂooding techniques to broadcast nodes location wastes bandwidth and energy. Reducing computa- tional complexity and communication overhead is essential in order to reduce power consumption, extend the life time of the battery operated nodes, and improve the performance of the lim- ited computational resources of these sensor nodes. In this paper, we revise the mathematical model,the analysis and the simulation experiments of the Trigonometric based Ad-hoc Localiza- tion System (TALS), a range-based localization system presented previously. Furthermore, the study is extended, and a new technique to optimize the system is proposed. An analysis and an extensive simulation for the optimized TALS (OTALS) is presented showing its cost, accuracy, and eﬃciency, thus deducing the impact of its parameters on performance. Hence, the contribution of this work can be summarized as follows: 1) Proposing and employing a novel modiﬁed Manhattan distance norm in the TALS localization process. 2) Analyzing and simulating of OTALS showing its computational cost and accuracy and comparing them with other related work. 3) Studying the impacts of diﬀerent parameters like anchor density, node density, noisy measurements, trans- mission range, and non-convex network areas. 4) Extending our previous joint work, TALS, to consider base anchors to be located in positions other than the origin and analyzing this work to illustrate the possibility of selecting a wrong quadrant at the ﬁrst iteration and how this problem is overcome. Through mathematical analysis and intensive simulation, OTALS proved to be it- erative, distributed, and computationally simple. It presented superior performance compared to other localization techniques.
hoped that proper proactive decisions can be taken before the paths are broken. However, the comparison with DSR (Dynamic Source Routing) is not fair since it is not a multipath routing protocol. The Multipath Energy Efficient Routing Protocol (MEERP)  is an extension of the existing routing protocol AOMDV. Route discovery is modified in MEERP, whereby each intermediate node is prohibited from generating a route reply message. The proposed protocol selects energy- efficient multiple node disjoint paths based on the residual energy and successful transmission rate. In this algorithm, multiple routing paths are selected. However, only one path is used for data transmission at a given time. During the path- discovery process, each intermediate node calculates the cumulative node cost until the destination, and the path with the highest cost is selected. This cost depends upon two measurements: the successful transmission rate and the residual energy of the node. The simulation results show that the proposed scheme can achieve a great improvement of the network lifetime by reducing end-to-end delay and overhead. In , the authors propose a multipath routing protocol based on AODV routing algorithm (ZD-AOMDV). The represented protocol in this study tries to discover the distinct paths between source and destination nodes with using Omni directional antennas, to send information through these simultaneously. This protocol counts the number of active neighbors for each path, and finally it chooses some paths for sending information in which each node has lower number of active neighbors all together. Here, active neighbors of a node are defined as nodes that have previously received the RREQ (Route Request).The aim of this work is to try to improve the energy efficiency of adhocnetworks.