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Cooperative communication can significantly enhance the efficient utilization of spectrum in wireless networks. The performance of wireless cooperative networks depends on careful medium access control (MAC) and resource allocation such as relay selection and cooperative link scheduling policy for interference management. Most of the previous centralized works rely on precise instantaneous channel state information (CSI). In this paper, considering the impact of multirelay link interference on relay selection and dynamic spectrum sharing, we propose a fully distributed relay MAC scheme for wireless cooperative networks based on a Stackelberg game framework with only one-hop local CSI, where source nodes that have their own information to send act as leader users and where the others act as follower users. In this scenario, each relay node prices its spectrum resource to the corresponding source node to maximize its revenue. In addition, the proposed scheme helps not only source nodes to find relay nodes by channel gains and obtain an optimal system performance but relay nodes to maximize their revenue by asking a suitable resource price as well. The interactions between the sources and relays iteratively lead to a Stackelberg equilibrium, in which the cooperation system achieves high throughput and low transmission delay. Simulation results are presented to show the effectiveness of the proposed approach. [ABSTRACT FROM PUBLISHER]

The infrastructure-less and dynamic nature of mobile ad hoc networks demands a new set of networking strategies to improve the performance of quality of service (QoS). Providing QoS is a major issue in Manets. The traditional layered approach does not fit well for ad hoc networks due to high mobility and dynamic topology. This paper implements the cross layer design approach on DYMO routing protocol in Manets by using Qualnet simulator in both traditional layered approach and proposed cross layer approach. The proposed methodology uses four QoS metrics: throughput, end-to-end delay, packet delivery ratio and jitter. The experimental result reveals that QoS performance is enhanced in CLD approach for DYMO. The throughput in traditional layered approach for DYMO is 1961 b/s, whereas in the CLD approach it is 2986 b/s. Finally this paper concludes that cross layer approach significantly improves the QoS performance when compared with layered approach. [ABSTRACT FROM AUTHOR]

In this paper, we study the impact of human mobility on throughput and delay for people-centric applications in mobile ad hoc networks (MANETs). We consider a general human mobility model for MANETs, which can capture important features of human mobility, such as time correlation, node correlation, location heterogeneity, and node heterogeneity. Multiple unicasts with general arrival processes are delivered, and nodes are equipped with infinite buffers. Under our system model, we first characterize the network stability region in terms of the probability of each node set visiting each location and the amount of transmission resources at each location. We show that the node correlation and heterogeneity of locations' popularity usually decrease the size of the network stability region, whereas the diversity of locations visited by a node usually increases the size of the network stability region. Then, by solving a stability-related optimization problem, we develop a throughput-optimal policy based on the obtained optimal solution. We obtain the upper and lower bounds of the delay performance under the proposed policy. Finally, using simulations based on a theoretical model and some real traces, we verify the analytical results and compare the performance of the proposed policy with some existing policies. [ABSTRACT FROM PUBLISHER]

The “first wave” of wireless ad hoc routing protocols was heavily influenced by the routing algorithms used in wired networks. However, their overheads due to topology changes and the implicit restriction to point-to-point control messages meant that extensive effort had to be expended in “fixing” them to fit the intricacies and opportunities offered by wireless environments. In this paper, we analyze and compare the most widely used routing protocols in mobile ad hoc networks (MANETs). In particular, we consider routing and control overheads, storage requirements, and network setup costs of these protocols to see how well they fit in MANETs with nodes that have scarce resources. [ABSTRACT FROM PUBLISHER]

This paper studies the performance of a general two-hop relay (2HR)- $(x,w,f) $ packet delivery scheme that combines both erasure coding and packet replication techniques in mobile ad hoc networks (MANETs). Under this packet delivery scheme, a group of $x$ packets is first encoded into $w(w\geq x) $ coded packets using erasure coding, and each coded packet is then replicated to at most $f$ distinct relay nodes that can help to forward the coded packets to its destination node. The original packets can be recovered when $x$ distinct coded packets reach the destination node. To understand the packet delivery process under the 2HR- $(x,w,f) $ scheme, we develop a multidimensional Markov chain framework, and based on this analytical expressions on the packet delivery ratio and corresponding expected packet delivery cost are further derived. Finally, extensive simulation and numerical studies are conducted to illustrate the efficiency of the developed theoretical models and to illustrate our findings. Our results indicate that the replication parameter $f$ should be carefully selected in order to obtain a high packet-delivery-ratio performance while maintaining a relatively low delivery cost. [ABSTRACT FROM PUBLISHER]

In this paper, we analyze the impact of network coding (NC) configuration on the performance of ad hoc networks with the consideration of two significant factors, namely, the throughput loss and the decoding loss, which are jointly treated as the overhead of NC. In particular, physical-layer NC and random linear NC are adopted in static and mobile ad hoc networks (MANETs), respectively. Furthermore, we characterize the goodput and delay/goodput tradeoff in static networks, which are also analyzed in MANETs for different mobility models (i.e., the random independent and identically distributed (i.i.d.) mobility model and the random walk model) and transmission schemes (i.e., the two-hop relay scheme and the flooding scheme). Moreover, the optimal configuration of NC, which consists of the data size, generation size, and NC Galois field, is derived to optimize the delay/goodput tradeoff and goodput. The theoretical results demonstrate that NC does not bring about order gain on delay/goodput tradeoff for each network model and scheme, except for the flooding scheme in a random i.i.d. mobility model. However, the goodput improvement is exhibited for all the proposed schemes in mobile networks. To our best knowledge, this is the first work to investigate the scaling laws of NC performance and configuration with the consideration of coding overhead in ad hoc networks. [ABSTRACT FROM PUBLISHER]

Mobile Ad-hoc NETworks (MANETs) is a set of mobile nodes that can move around arbitrarily, and communicate with others in a multi-hop fashion without any assistance of base stations. With recent advances in Cognitive Radio (CR) technology, it is possible to apply the Dynamic Spectrum Access model in MANETs. This introduces the concept of Cognitive Radio Ad Hoc Networks (CRAHNs). Applying CR techniques provides better throughput, even in congested spectrum along with better propagation characteristics. CRAHN is a kind of intelligent network that is aware of its surrounding environment, and adapts to the transmission or reception parameters to achieve efficient communication without interfering with primary users. Routing in CR environment is a challenging task as the availability of channel is constrained by the presence of primary user. The problem of routing in CRAHNs targets the creation and maintenance of wireless multi-hop paths among cognitive nodes by deciding both the spectrum to be used and the relay nodes of the path. This paper proposes a cognitive cross-layer multipath probabilistic routing for cognitive radio based networks. The proposed solution uses spectrum holes identified by MAC layer, decides the channel to be used and transmit power level for each hop in the path. The proposed solution is implemented in NS2, and performance of the proposed solution is compared with the existing solution from the literature. The paper also shows that the proposed solution outperforms existing solution in terms of packet delivery ratio, average end-to-end delay and energy consumed per data packet. [ABSTRACT FROM AUTHOR]

In this paper, we present a methodology employing statistical analysis and stochastic geometry to study geometric routing schemes in wireless ad hoc networks. In particular, we analyze the network-layer performance of one such scheme, the random 1\over 2disk routing scheme, which is a localized geometric routing scheme in which each node chooses the next relay randomly among the nodes within its transmission range and in the general direction of the destination. The techniques developed in this paper enable us to establish the asymptotic connectivity and the convergence results for the mean and variance of the routing path lengths generated by geometric routing schemes in random wireless networks. In particular, we approximate the progress of the routing path toward the destination by a Markov process and determine the sufficient conditions that ensure the asymptotic connectivity for both dense and large-scale ad hoc networks deploying the random 1\over 2disk routing scheme. Furthermore, using this Markov characterization, we show that the expected length (hop count) of the path generated by the random 1\over 2disk routing scheme normalized by the length of the path generated by the ideal direct-line routing, converges to 3\pi /4 asymptotically. Moreover, we show that the variance-to-mean ratio of the routing path length converges to 9\pi ^2/64-1 asymptotically. Through simulation, we show that the aforementioned asymptotic statistics are in fact quite accurate even for finite granularity and size of the network. [ABSTRACT FROM PUBLISHER]

A sequence of online messages for connections is given, each message is important and thide failure of delivering a message is a critical event. The maximum lifetime problem maximizes the total number of messages that can be successfully sent over the network. Given a $$h\ge 1$$ , this paper presents two new problems on ad hoc networks (called the min-max and min-sum cost online problems), which adjust the initial energies of nodes such that the network can send the first $$h$$ messages. We consider the min-sum and min-max norms for minimizing the cost of adjusting the initial energies. This paper presents an algorithm for these problems and computes upper bounds for the total cost of the min-sum and min-max norms. Mohanoor et al. (Ad hoc Networks 7: 918-931, ) presented three algorithms (called SWRP, SFWP and SWCRP algorithms) to online energy aware routing, which, in practice, are better than other algorithms on lifetime in the cases: the effect of session length, transmission radius and node density. This paper modifies these algorithms (the modifies algorithms are called TSWRP, TSFWP and TSWCRP) so that they compute the total cost of the min-sum and min-max norms. Then, we show, in practice, the total cost of the min-sum and min-max norms computed by our algorithm are smaller than the values computed by the TSWRP, TSFWP and TSWCRP algorithms in the cases: the transmission radius and node density. Also, in practice, the lifetime of our algorithm is more than the lifetime of the SWRP, SFWP and SWCRP algorithms in the cases: the effect of session length and node density. [ABSTRACT FROM AUTHOR]

The study of energy constrained routing protocols in mobile Ad Hoc Networks (MANET) is attracting more attention recently. The typical MANET routing protocols of IETF are shortest routing protocols, that is, the least hops but do not consider the energy aware problem. Because the ad hoc networks is an energy constrained system with the portable devices, it is a very important metric to evaluate the routing protocols whether which have a longer network lifetime or not. Based on the mobile node energy level and using the different forward tactics, this paper presents an energy level based routing protocol-ELBRP. The routing protocol not only makes the system energy consumption low but also prolongs the system lifetime and improves the delay characteristic. In this paper, the proof of correctness and complexity analysis of ELBRP are given. This paper compares the performance of existing protocols AODV, RDRP and proposed ELBRP via simulation. The simulation result shows that ELBRP has a better delay performance, a lower energy consumption and longer network lifetime than the other two and provides an available approach to as hoc networks routing. [ABSTRACT FROM AUTHOR]

Encouraging cooperation and deterring selfish behaviors are important for proper operations of mobile ad hoc networks (MANETs). For this purpose, most previous efforts rely on either reputation systems or price systems. However, these systems are neither sufficiently effective in providing cooperation incentives nor sufficiently efficient in resource consumption. Nodes in both systems can be uncooperative while still being considered trustworthy. Also, information exchange between mobile nodes in reputation systems and credit circulation in price systems consumes significant resources. This paper presents a hierarchical Account-aided Reputation Management system (ARM) to efficiently and effectively provide cooperation incentives. ARM builds a hierarchical locality-aware distributed hash table (DHT) infrastructure for efficient and integrated operation of both reputation and price systems. The infrastructure helps to globally collect all node reputation information in the system, which can be used to calculate more accurate reputation and detect abnormal reputation information. Also, ARM integrates reputation and price systems by enabling higher-reputed nodes to pay less for their received services. Theoretical analysis demonstrates the properties of ARM. Simulation results show that ARM outperforms the individual reputation system and price system in terms of effectiveness and efficiency of providing cooperation incentives and deterring selfish behaviors. [ABSTRACT FROM PUBLISHER]

The objective of multirobot task allocation (MRTA) is to assign tasks to robots to minimize the overall cost of task performance. This paper proposes a decentralized MRTA approach considering the robots' residual expendable resources and their limited communication ranges. The proposed approach consists of two algorithms, namely, resource-aware cost generation (RCG) and ad hoc network-based task allocation (ANTA). The RCG algorithm allows each robot to generate a credible cost of task performance considering its residual resources in task planning. The ANTA algorithm constructs the minimal spanning tree network among the robots and determines the robot with the lowest cost for the task through multihop communication in a decentralized manner. The advantages of the proposed approach are minimization of unnecessary task performance cost caused by resource shortage of robots during task execution and the use of an ad hoc network among the robots to allow more robots to participate in the task allocation process. The effectiveness of the proposed approach is demonstrated through computer simulations for multirobot foraging as a test problem. [ABSTRACT FROM PUBLISHER]

The distinctive features of mobile ad hoc networks (MANETs), including dynamic topology and open wireless medium, may lead to MANETs suffering from many security vulnerabilities. In this paper, using recent advances in uncertain reasoning that originated from the artificial intelligence community, we propose a unified trust management scheme that enhances the security in MANETs. In the proposed trust management scheme, the trust model has two components: trust from direct observation and trust from indirect observation. With direct observation from an observer node, the trust value is derived using Bayesian inference, which is a type of uncertain reasoning when the full probability model can be defined. On the other hand, with indirect observation, which is also called secondhand information that is obtained from neighbor nodes of the observer node, the trust value is derived using the Dempster–Shafer theory (DST), which is another type of uncertain reasoning when the proposition of interest can be derived by an indirect method. By combining these two components in the trust model, we can obtain more accurate trust values of the observed nodes in MANETs. We then evaluate our scheme under the scenario of MANET routing. Extensive simulation results show the effectiveness of the proposed scheme. Specifically, throughput and packet delivery ratio (PDR) can be improved significantly with slightly increased average end-to-end delay and overhead of messages. [ABSTRACT FROM AUTHOR]

In this work a new protocol for Voice over IP (VoIP) transmissions in wireless ad-hoc networks is proposed. Distributed architecture is necessary when dealing with dynamic environments, such as ports or battlefields, where creating infrastructures becomes expensive or impossible. Mobile ad-hoc networks (MANETs) are based on a peer-to-peer approach and each node participates in the organization of the whole network. VoIP over MANETs is a challenging issue due to the intrinsic distributed nature of the existing peer-to-peer paradigm. This paper proposes a new protocol, capable of ensuring a quality of service (QoS) level for VoIP calls over a MANET and to manage a large number of calls in the system. Novel metric and utility functions are proposed to perform the best path selection from source to destination nodes, respecting the QoS parameters for VoIP quality. In particular, an objective metric such as R-factor is considered, and a flexibility index is defined in order to maximize the number of acceptable VoIP calls. Performance evaluation shows that the proposed approach led to better network management in terms of admitted calls and respected QoS constraints. [ABSTRACT FROM AUTHOR]

Wireless communication is continuing to make inroads into many facets of society and is gradually becoming more and more ubiquitous. While in the past wireless communication (as well as mobility) was largely limited to the first and last transmission hops, today?s wireless networks are starting to offer purely wireless, often mobile, and even opportunistically connected operation. The purpose of this article is to examine security and privacy issues in some new and emerging types of wireless networks, and attempt to identify directions for future research. [ABSTRACT FROM PUBLISHER]

Unmanned aerial vehicles (UAVs) networks have not yet received considerable research attention. Specifically, security issues are a major concern because such networks, which carry vital information, are prone to various attacks. In this paper, we design and implement a novel intrusion detection and response scheme, which operates at the UAV and ground station levels, to detect malicious anomalies that threaten the network. In this scheme, a set of detection and response techniques are proposed to monitor the UAV behaviors and categorize them into the appropriate list (normal, abnormal, suspect, and malicious) according to the detected cyber-attack. We focus on the most lethal cyber-attacks that can target an UAV network, namely, false information dissemination, GPS spoofing, jamming, and black hole and gray hole attacks. Extensive simulations confirm that the proposed scheme performs well in terms of attack detection even with a large number of UAVs and attackers since it exhibits a high detection rate, a low number of false positives, and prompt detection with a low communication overhead. [ABSTRACT FROM AUTHOR]

The narrow-beam operation in millimeter wave (mmWave) networks minimizes the network interference leading to noise-limited networks in contrast with interference-limited ones. The medium access control (MAC) layer throughput and interference management strategies heavily depend on the noise-limited or interference-limited regime. Yet, these regimes are not considered in recent mmWave MAC layer designs, which can potentially have disastrous consequences on the communication performance. In this paper, we investigate the performance of cache-enabled MAC-based mmWave ad hoc networks, where randomly distributed nodes are supported by a cache. The ad hoc nodes are modeled as homogenous Poisson point processes. Specifically, we study the optimal content placement (or caching placement) at desirable mmWave nodes using a network model that accounts for uncertainties both in node locations and blockages. We propose a contention-based multimedia delivery protocol to avoid collisions among the concurrent transmissions. Subsequently, only the node with smallest back-off timer among its contenders is allowed to transmit. We then characterize the average success probability of content delivery. We also characterize the cache hit ratio probability, and transmission probability of this system under essential factors, such as blockages, node density, path loss, and caching parameters. [ABSTRACT FROM AUTHOR]

Emerging vehicle-to-vehicle communication technologies, such as dedicated short range communications (DSRC), offer unique opportunities to realize wireless peer-to-peer systems for vehicles. A critical component in a vehicular peer-to-peer system is an efficient content reconciliation mechanism, which guides two communicating vehicles to match their interests, prioritize task execution, and ensure redundant contents not to be exchanged. In this paper, we propose PYRAMID, a multilayer probabilistic abstraction framework, to efficiently abstract and approximate contents with different granularity. Using the multilayer Pyramid data structures, a vehicle is able to quickly get an impression of the contents on the other vehicle before the costly massive content exchange process starts. Particularly, the coarse-granularity layer estimates the contribution from potential transaction partners so that tasks could be prioritized accordingly; the fine-granularity layer helps conduct membership tests, to avoid transmitting redundant contents. Using a fleet of research vehicles equipped with DSRC radios, we experimentally demonstrate that, across a rich variety of scenarios, PYRAMID improves the utility value of content exchanges by 20%–30% and improves effective throughput by at least 25%, while only incurring a minimal computational overhead. [ABSTRACT FROM AUTHOR]

Recent studies in wireless scheduling have shown that carrier-sense multiple access (CSMA) can be made throughput optimal by optimizing over activation rates. However, those throughput optimal CSMA algorithms were found to suffer from poor delay performance, especially at high throughputs where the delay can potentially grow exponentially in the size of the network. Motivated by these shortcomings, in this paper we propose a node-based version of the throughput optimal CSMA (NB-CSMA) as opposed to traditional link-based CSMA algorithms, where links were treated as separate entities. Our algorithm is fully distributed and corresponds to Glauber dynamics with “Block updates”. We show analytically and via simulations that NB-CSMA outperforms conventional link-based CSMA in terms of delay for any fixed-size network. We also characterize the fraction of the capacity region for which the average queue lengths (and the average delay) grow polynomially in the size of the network, for networks with bounded-degree conflict graphs. This fraction is no smaller than the fraction known for link-based CSMA, and is significantly larger for many instances of practical wireless ad-hoc networks. Finally, we restrict our focus to the special case of collocated networks, analyze the mean starvation time using a Markov chain with rewards framework and use the results to quantitatively demonstrate the improvement of NB-CSMA over the baseline link-based algorithm. [ABSTRACT FROM AUTHOR]

Effective clustering algorithms are indispensable in order to solve the scalability problem in vehicular ad hoc networks. Although current existing clustering algorithms show increased cluster stability under some certain traffic scenarios, it is still hard to address which clustering metric performs the best. In this paper, we propose a unified framework of clustering approach (UFC), composed of three important parts: 1) neighbor sampling; 2) backoff-based cluster head selection; and 3) backup cluster head based cluster maintenance. Three mobility-based clustering metrics, including vehicle relative position, relative velocity, and link lifetime, are considered in our approach under different traffic scenarios. Furthermore, a detailed analysis of UFC with parameters optimization is presented. Extensive comparison results among UFC, lowest-ID, and VMaSC algorithms demonstrate that our clustering approach performs high cluster stability, especially under high dynamic traffic scenarios. [ABSTRACT FROM PUBLISHER]

Low-cost sensors and ubiquitous wireless networking is enabling novel ways in which homeowners can interact with their smart homes. Many complementary approaches like using voice commands, direct interaction by using touch or weight, or by using body gestures are emerging. This paper shows the design and implementation of a novel low-power, low-cost, hand-held wireless device called a SensePod. SensePods can be used by a consumer to interact with a smart home using simple gestures like rubbing, taping or rolling the device on any home surface like a dining table. The device is only 4.5 cm long, forms an ad-hoc wireless network using the ZigBee protocol, and can be easily interfaced to existing home management systems using a universal serial bus port. The gestures in each device can be programmed to control various objects of a smart home like smart curtains, for example. Hidden Markov models were used to train the device to recognize various gestures. The device was tested with a variety of gestures and has a recognition rate of over 99.7%, and a response time of less than two milliseconds. [ABSTRACT FROM AUTHOR]

This paper presents a novel data and timed control routing protocol which is Flying Adhoc Network (FANET) specific. The developed FANET specific routing protocol laid emphasis on the route connectivity in the network by considering the captured data size, minimum allowable distance between randomly moving nodes and connection time. The performance of the proposed FANET specific routing protocol was simulated using NS3. The obtained throughput value for the routing protocol fluctuated between 742.064kbps and 755.083kbps as data are exchanged between nodes. This showed that when all the UAVs are on the network and communicating with one another, the throughput is flatline and not plummet. This implies consistency as nodes join and leave the network. The packet delivery ratio obtained for the FSRP during simulation was 96.13%. These results implied that data is successfully transmitted between the UAV acting as server and UAV acting as client on the network. [ABSTRACT FROM AUTHOR]

Neighbor discovery is the procedure in which two wireless devices initiate a first contact. In low power ad-hoc networks, radios are duty-cycled and the latency until a packet meets a reception phase of another device is determined by a random process. Most research considers slotted protocols, in which the points in time for reception are temporally coupled to beacon transmissions. In contrast, many recent protocols, such as ANT/ANT+ and Bluetooth Low Energy (BLE) use a slotless, periodic-interval based scheme for neighbor discovery. Here, one device periodically broadcasts packets, whereas the other device periodically listens to the channel. Both periods are independent from each other and drawn over continuous time. Such protocols provide 3 degrees of freedom (viz., the intervals for advertising and scanning and the duration of each scan phase). Though billions of existing BLE devices rely on these protocols, neither their expected latencies nor beneficial configurations with good latency-duty-cycle relations are known. Parametrizations for the participating devices are usually determined based on a “good guess”. In this paper, we, for the first time, present a mathematical theory which can compute the neighbor discovery latencies for all possible parametrizations. Further, our theory shows that upper bounds on the latency can be guaranteed for all parametrizations, except for a finite number of singularities. Therefore, slotless, periodic interval-based protocols can be used in applications with deterministic latency demands, which have been reserved for slotted protocols until now. Our proposed theory can be used for analyzing the neighbor discovery latencies, for tweaking protocol parameters and for developing new protocols. [ABSTRACT FROM AUTHOR]

This paper studies resource scheduling for wireless small cloud assuming that the execution of an application is modeled as a workflow graph. A scheduling method is proposed which consists of two parts. For the task-to-computing-unit assignment part which operates on the long-term time-scale, the solution is to partition the workflow into task groups which have loose data transfer constraint and each task group is assigned to the computing unit which can finish executing the task group at the earliest time. For the computing and wireless communication resource scheduling part which operates on the short-term time-scale, we simply use the round-robin principle. A part by part delay component estimation method is presented based on which the average delay performance can be analyzed. Simulation results validate the theoretical analysis and show that the proposed method outperforms existing methods. The impact of different parameter settings on the system performance is also investigated. [ABSTRACT FROM AUTHOR]

This paper investigates simultaneous wireless information and power transfer (SWIPT) in the ad hoc network, where access points (APs) with multiple antennas can transfer energy as well as information using a common spectrum resource. The receiving nodes decode the incoming information data (information decoding, ID) and/or harvest the RF energy (energy harvesting, EH), where two different receiving node architectures—time switching (TS) and power splitting (PS)—are considered. By using a stochastic geometry approach, we aim to analyze the transmission capacity and the harvested energy per unit area as performance measures of the SWIPT in the ad hoc network. From the analytical results, we can derive the optimal node densities of ID nodes and EH nodes for TS architectures and, furthermore, optimize the power splitting ratio jointly with the node density for the PS architectures such that the harvested energy per unit area is maximized when the target transmission capacity is given. The proposed node density optimization gives us a useful insight into the design of SWIPT-based ad hoc network, where we can show how densely the APs/nodes can be deployed in a given area and furthermore, find that the ad hoc network with PS receiving nodes outperforms that with TS receiving nodes for a large target transmission capacity, and vice versa. [ABSTRACT FROM AUTHOR]

With the development of aeronautical telecommunication and unmanned aerial vehicles (UAVs), wireless networks will be extended to three-dimensional (3-D) space. Besides, 3-D wireless networks have been widely deployed in battlefields, which consist of aircraft, UAVs, ground troops, and fleets. When nodes in these wireless networks form swarm and cooperate with each other, there will be social behavior among them and 3-D wireless social networks emerge. Although the study of wireless social networks has been initiated, the capacity of 3-D wireless social networks is unknown. In this paper, we derive the achievable capacity of 3-D wireless social networks. It shows that the capacity is a function of the pathloss exponent, the number of nodes, the social group concentration, the contact concentration, and the size of social group. When the social group concentration or the contact concentration exceeds a threshold, the wireless social network is scalable and the capacity of wireless social network is much larger than that of the wireless network without social behavior. Besides, we discover the existence of a singular point for social group concentration and contact concentration, where the network capacity skips to a larger value than the neighborhood. The results reveal the interplay between wireless communication and social connection in 3-D space, which brings an insight into the design of 3-D wireless networks. [ABSTRACT FROM AUTHOR]

Cooperative multicast serves as an efficient communication paradigm for supporting multicast-intensive applications in mobile ad hoc networks (MANETs). Available studies on cooperative multicast in MANETs mainly focus on either the full cooperation or the noncooperation, which fail to capture the more general cooperation behaviors among destination nodes. To address this issue, this paper proposes a general cooperative multicast scheme CM( $f,g, p,\tau$) with replication factor $f$, multicast fanout $g$, cooperative probability $p$ , and packet lifetime $\tau$. With this scheme, a packet from source node will be replicated to at most $f$ distinct relay nodes, which forward the packet to its $g$ destination nodes, and with probability $p$ a destination node helps to forward the packet. Here, the packet has the lifetime of $\tau$ time slots. The scheme is flexible and general, and it covers the full cooperation ($p = 1$) and the noncooperation ($p = 0$ ) as special cases. A Markov chain theoretical model is further developed to depict the packet delivery process under the new scheme and help us to conduct analytical study on the corresponding expected packet delivery probability and packet delivery cost. Finally, extensive simulation and numerical results are provided for discussions. [ABSTRACT FROM AUTHOR]

With the remarkable progress of cooperative communication technology in recent years, its transformation to vehicular networking is gaining momentum. Such a transformation has brought a new research challenge in facing the realization of cooperative vehicular networking (CVN). This paper presents a comprehensive survey of recent advances in the field of CVN. We cover important aspects of CVN research, including physical, medium access control, and routing protocols, as well as link scheduling and security. We also classify these research efforts in a taxonomy of cooperative vehicular networks. A set of key requirements for realizing the vision of cooperative vehicular networks is then identified and discussed. We also discuss open research challenges in enabling CVN. Lastly, the paper concludes by highlighting key points of research and future directions in the domain of CVN. [ABSTRACT FROM PUBLISHER]

Traditional marine monitoring systems such as oceanographic and hydrographic research vessels use either wireless sensor networks with a limited coverage, or expensive satellite communication that is not suitable for small and mid-sized vessels. This paper proposes a novel Internet of Marine Things data acquisition and cartography system in the marine environment using Very High Frequency (VHF) available on the majority of ships. The proposed system is equipped with many sensors such as sea depth, temperature, wind speed and direction, and the collected data is sent to 5G edge cloudlets connected to sink/base station nodes on shore. The sensory data is ultimately aggregated at a central cloud on the internet to produce up to date cartography systems. Several observations and obstacles unique to the marine environment have been discussed and feed into the solutions presented. The impact of marine sparsity on the network is examined and a novel hybrid Mobile Ad-hoc/Delay Tolerant routing protocol is proposed to switch automatically between Mobile Ad-hoc Network and Delay Tolerant Network routing according to the network connectivity. The low rate data transmission offered by VHF radio has been investigated in terms of the network bottlenecks and the data collection rate achievable near the sinks. A data synchronization and transmission approach has also been proposed at the 5G network core using Information Centric Networks. [ABSTRACT FROM PUBLISHER]

In this paper, we cope with the reliable and efficient data transfer problem in aeronautical ad hoc networks (AANETs). AANETs are different from terrestrial ad hoc networks and these distinctions feature AANETs with large propagation delay, highly dynamic network topology, and high error probability, which pose many new challenges for data transfer in such environments. In this paper, we propose a protocol, called FRUDP, which combines reliable UDP and fountain code to achieve reliable and efficient data transfer in AANETs. It employs Raptor codes to recover from data losses to mitigate retransmission caused by high channel losses in AANETs. A code rate determining algorithm is developed to estimate the redundancy on the fly by taking into full consideration the time-varying aeronautical network conditions. Moreover, the improved selective negative acknowledgment scheme is utilized to solve the bandwidth asymmetry problem in AANETs and a congestion control scheme is deployed to decouple congestion decisions from packet losses in order to avoid the erroneous congestion decisions due to frequent link handoffs. The proposed FRUDP is fully implemented directly on top of UDP in Linux and examined over a variety of emulation network environments. The experimental results show that FRUDP is suitable for reliable and efficient data transfer service in AANETs. [ABSTRACT FROM PUBLISHER]

Satellite communications can be used when other communication systems are either destroyed or overloaded. Observation satellites and delay/disruption tolerant networks (DTNs) are technologies that can be interconnected to provide emergency communication for disaster recovery operations. DTNs use a store-carry-forward mechanism to forward messages through intermediary nodes to the destination node. The reliability of relaying messages through multi-hop nodes poses a significant problem in DTNs due to lack of consistent connectivity. These network characteristics make DTNs to heavily rely on the cooperation of neighboring nodes for the successful delivery of packets. However, the presence of malicious or selfish nodes will have a great impact on the network performance. In this paper, we design a decentralized trust management scheme (DTMS) to filter out malicious nodes in DTNs. First, the number of forwarding evidence is combined with the energy consumption rate of the nodes to formulate direct trust. Then, a recommendation trust is computed from the indirect trust, recommendation credibility, and recommendation familiarity. Recommendation credibility and familiarity improve the overall recommendation trust by filtering out dishonest recommendations. A comparative analysis of DTMS is performed against a cooperative watchdog scheme, recommendation based trust model, and spray and wait protocol. The results show that DTMS can effectively deal with malicious behaviors in DTNs including trust related attacks. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a new caching scheme for a random wireless device-to-device (D2D) network of $n$ nodes with local caches, where each node intends to download files from a prefixed library via D2D links. Our proposed caching delivery includes two stages, employing distributed MIMO and hierarchical cooperations, respectively. The distributed MIMO is applied to the first stage between source nodes and neighbors of the destination node. The induced multiplexing gain and diversity gain increase the number of simultaneous transmissions, improving the throughput of the network. The hierarchical cooperations are applied to the second stage to facilitate the transmissions between the destination node and its neighbors. The two stages together exploit spatial degrees of freedom as well as spatial reuse. We develop an uncoded random caching placement strategy to serve this cooperative caching delivery. Analytical results show that the average aggregate throughput of the network scales almost linearly with $n$ , with a vanishing outage probability. Furthermore, we derive an explicit expression of the optimal throughput as a function of system parameters, such as pathloss factor under a target outage probability. Analytical and numerical results demonstrate that our proposed scheme outperforms existing ones when the local cache size is limited. [ABSTRACT FROM PUBLISHER]

Neighbor discovery (ND) is an essential prerequisite for any peer-to-peer communication. In general, minimizing the discovery time is the goal for ND schemes. In this paper, we study the average discovery time for directional random ND when nodes have prior information about their set of possible neighbors, which also helps identify the performance limits of random ND schemes. Typically, discovery time analysis is done for assumptions that simplify the network structure, such as uniform neighbor relations for all nodes. However, with prior information the directional transmission probabilities depend on the node and the direction. This complicates the analysis of the expected discovery time. We first provide a closed-form expression for the expected discovery time based on the non-uniform coupon collector problem. Next, we identify directional transmission probabilities of each node that achieve a small discovery time. Due to the mathematical complexity, we provide a lower and an upper bound on the expected discovery time, which allows us to write the problem as a convex optimization problem. Through simulations, we demonstrate the performance gain due to prior knowledge with the proposed methods as compared with when no prior information is available, as well as the impact of uncertainty in the prior knowledge. [ABSTRACT FROM PUBLISHER]

Communications-based train control (CBTC) is a modern signaling system that uses radio communication to transfer train control information between the train and the wayside. A vast majority of CBTC systems worldwide use IEEE 802.11 Wi-Fi as the radio technology mostly due to its cost effectiveness. The trackside networks in these systems are mostly based on the conventional infrastructure Wi-Fi. It means a train has to continuously associate (i.e., perform handshake) with the trackside Wi-Fi access points (AP) as it moves. This is a time-consuming process associated with a certain delay. Additionally, these APs are connected to the wayside infrastructure via optical fiber cables that incurs huge costs. This paper presents a novel design in which trackside nodes function in ad-hoc Wi-Fi mode, which means no association has to be performed with them prior to transmitting. A train simply broadcasts packets to any nodes in its range. A node upon receiving these packets forwards them to the next node and so on, forming a chain of nodes. Following this chain, packets arrive at the destination. To make the design resilient against interference, transmissions are separated on multiple frequencies. Furthermore, redundancy is introduced in the design as a node forwards packets to not only one but two of its neighbors. This paper investigates the performance of the new design from the perspective of resiliency, redundancy, and scalability, and presents the results both from a field experiment carried out using prototype hardware and an extensive simulations study. [ABSTRACT FROM PUBLISHER]

A mobile ad-hoc network (MANET) is composed of mobile nodes without any infrastructure where member nodes easily can leave or join the network. This issue provides a dynamic topology network such that providing quality of service and multicast services are very challenging tasks. The majority of applications of MANETs are in rapid deployment and dynamic reconfigurations. For these reasons, in this paper, we present an efficient fuzzy logic based multicast routing scheme to adaptively manage the network resources without any prior knowledge about network traffic. Every source node self-organizes the multicast session by using average end to end delay and packet delivery ratio parameters in order to dynamically adjust its own sending rate. The proposed method is a novel framework for multicast services such that it can be deployed by both tree-based and mesh-based multicast routing protocols. In addition, The proposed method uses a cross-layer technique to efficiently manage the congestion. The results show high improvement in terms of number of the retransmissions, delay, packet delivery ratio and overhead compared to the existing multicast schemes. [ABSTRACT FROM AUTHOR]