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This paper considers multichannel slotted ALOHA for unicast in an ad hoc network. Under a deadline-constrained scenario that a packet is required to be transmitted to an intended recipient within a strict delivery deadline $D$ (in unit of slot) and retransmission is not allowed, we obtain the optimal channel selection probabilities and the optimal transmission probability that maximize the reliability. In particular, the throughput maximization can be studied as the case of $D =1$. Furthermore, by noting that there is a tradeoff between reliability and throughput when $D>1$ , we obtain the optimal schedule that maximizes the reliability subject to a throughput constraint and the one that maximizes the throughput subject to a reliability constraint. [ABSTRACT FROM AUTHOR]

A set of $k~(\geqslant 2)$ spanning trees in the underlying graph of a network topology is called completely independent spanning trees, (CISTs for short), if they are pairwise edge-disjoint and inner-node-disjoint. Particularly, if $k=2$ , the two CISTs are called a dual-CIST. However, it has been proved that determining if there exists a dual-CIST in a graph is an NP-hard problem. Kwong et al. [IEEE/ACM Transactions Networking 19(5) 1543–1556, 2011] defined that a routing is protected, if there is an alternate with loop-free forwarding, when a single link or node failure occurs. Shortly afterward, Tapolcai [Optim. Lett. 7(4) 723–730, 2013] showed that a network possessing a dual-CIST suffices to establish a protection routing. It is well-known that Cayley graphs have a large number of desirable properties of interconnection networks. Although many results of constructing dual-CISTs on interconnection networks have been proposed in the literature, so far, the work has not been dealt with on Cayley graphs due to that their expansions are in exponential scalability. In this paper, we try to make a breakthrough of this work on some famous subclasses of Cayley graphs, including alternating group networks, bubble-sort network, and star networks. We first propose tree searching algorithms for helping the construction of dual-CISTs on low-dimensional networks. Then, by inductive construction, we show that dual-CISTs on high-dimensional networks can also be constructed agreeably. As a result, we can configure protection routings by using the constructed dual-CISTs. In addition, we complement some analysis with a simulation study of the proposed construction to evaluate the corresponding performance. [ABSTRACT FROM AUTHOR]

Multi-channel cognitive radio ad hoc networks (CRAHNs) and information-centric networking (ICN) will be indispensable for enabling envisioned multimedia-based smart services within the umbrella of smart cities. Cognitive radios enable the efficient and opportunistic use of spectrum bands by using vacant licensed channels, whereas information- centric networking improves content distribution by decoupling producers and consumers. In this work, we discuss the design of information-centric cognitive radio-based networking for multimedia- based applications in smart cities. We examine the potential of the joint design of CRAHNs and ICN, and thoroughly review fundamental aspects and challenges of CR and ICN for smart cities. Subsequently, we qualitatively study the capability of information-centric cognitive radio-based networking for improving network connectivity, content search and distribution, reliability and confined delay in smart city safety and infotainment-based applications. Finally, we highlight future research directions for the design of protocols for this envisioned network that will support smart cities. [ABSTRACT FROM AUTHOR]

In the last years, vehicular networking has grown up in terms of interest and transmission capability, due to the possibility of exploiting the distributed communication paradigm in a mobile scenario, where moving nodes are represented by vehicles. The different existing standards for vehicular ad-hoc networks, such as dedicate short range communication (DSRC), wireless access for vehicular environment (WAVE)/IEEE802.11p, have given to the research community the possibility of developing new medium access control (MAC) and routing schemes, in order to enhance the quality and the comfort of mobile users who are driving their vehicles. In this paper, we focus our attention on the optimization of traffic flowing in a vehicular environment with vehicle-2-roadside capability. As shown later, the proposed idea exploits the information that is gathered by road-side units to redirect traffic flows (in terms of vehicles) to less congested roads, with an overall system optimization, also in terms of carbon dioxide emissions reduction. An analytical model, as well as a set of pseudo-code instructions, have been introduced in the paper. A deep campaign of simulations has been carried out to give more effectiveness to our proposal. [ABSTRACT FROM AUTHOR]

Applications of the Internet of Things (IoT) require validation considering many types of environments before their actual implementation. Generally, the validation of these systems may be conducted by software through the use of emulators and simulators. However, the validation by software has limitations that can prevent a realistic approximation of the system behavior in real environments. For this reason, the scientific community has dedicated a great deal of effort to develop experimental testbeds. In light of this, we present a review of the state-of-the-art related to the testbeds for wireless sensor networks and IoT applications. In addition, we carried out a comparative analysis considering the technical specifications of the selected testbeds and highlighted their capabilities. Finally, we conclude with a discussion of the advantages and limitations of the testbeds with regard to the key requirements needed for IoT experimentation. [ABSTRACT FROM AUTHOR]

The engineering vision of relying on the “smart sky” for supporting air traffic and the “internet-above-the-clouds” for in-flight entertainment has become imperative for the future aircraft industry. Aeronautical ad hoc networking (AANET) constitutes a compelling concept for providing broadband communications above clouds by extending the coverage of air-to-ground (A2G) networks to oceanic and remote airspace via autonomous and self-configured wireless networking among commercial passenger airplanes. The AANET concept may be viewed as a new member of the family of mobile ad hoc networks (MANETs) in action above the clouds. However, AANETs have more dynamic topologies, larger and more variable geographical network size, stricter security requirements, and more hostile transmission conditions. These specific characteristics lead to more grave challenges in aircraft mobility modeling, aeronautical channel modeling, and interference mitigation as well as in network scheduling and routing. This paper provides an overview of AANET solutions by characterizing the associated scenarios, requirements, and challenges. Explicitly, the research addressing the key techniques of AANETs, such as their mobility models, network scheduling and routing, security, and interference, is reviewed. Furthermore, we also identify the remaining challenges associated with developing AANETs and present their prospective solutions as well as open issues. The design framework of AANETs and the key technical issues are investigated along with some recent research results. Furthermore, a range of performance metrics optimized in designing AANETs and a number of representative multiobjective optimization algorithms are outlined. [ABSTRACT FROM AUTHOR]

Existing communication protocols for mobile ad hoc networks (MANETs) mis-fit flying ad hoc networks (FANETs) due to their exclusive design challenges on the typical long communication distance and high mobility degree of nodes. To tackle them, we introduce a hybrid omnidirectional and multi-beam directional antenna structure for gradient-elastic control-data separation. Based on dual antennas, we further propose a novel communication strategy, which combines location prediction with target tracing, to catch and trace communication targets by adaptively exchanging heartbeat locations for stable data transmission. The performance evaluation shows that our proposal achieves 35.8% increase in data link robustness. [ABSTRACT FROM AUTHOR]

A key factor limiting the democratisation of networked systems is the lack of trust, particularly in the wake of data-intensive applications that work on sensitive and private data, which requires providing strong network security guarantees via encryption and authentication algorithms, as well as rethinking algorithms to compute on the network peripheries without moving data. In many security and privacycritical domains such as Home Automation IoT networks, AUV networks etc., the existence of a centralized privileged node leads to a vulnerability for leakage of sensitive information. In this paper, we have proposed a decentralized networking architecture that adopts collaborative processing techniques and operates within the tradeoff between network security and performance. We have investigated the design and sustainability of autonomous decentralized systems and evaluated the efficiency of the proposed scheme with the help of extensive simulation tools. [ABSTRACT FROM AUTHOR]

Crowd management aims to develop support infrastructures that can effectively manage crowds at any time. In emergency and disruptive scenarios this concept can minimize the risk to human life and to the infrastructure. We propose the Communication Architecture for Crowd Management (CACROM), which can support crowd management under emergency and disruptive scenarios. We identify, describe, and discuss the various components of the proposed architecture, and we briefly discuss open challenges in the design of crowd management systems for emergency and disruptive scenarios. [ABSTRACT FROM AUTHOR]

This article presents a knowledge mining model, where a city can plan its development based on existing knowledge during city expansion, for example, telecommunication resource allocation and crowd forecasts in a new region. Unlike most works that focused on Internet-of- Things (IoT) sensing, this study is aimed at urban planning by using harvested data, from the perspective of city architects. For large-scale metropolitan areas, a massive amount of data is generated every day, either from static surveys or dynamic IoT sensing. For urban planners, data collection is not their primary concern. How to transfer harvested knowledge from exiting parts of the city to suburban/rural/untapped areas is a new challenge. This is because those areas still lack sufficient statistics, and the density of IoT deployment is low. Therefore, development is risky and uncertain. To exploit new regions requires knowledge inference. Such a transition needs data interpretation from historical city dynamics, involving sensor deployment, human activities, and resource allocation in the vicinity. With the proposed model, a city can estimate the requirement for resources when the peripheral areas on the outskirts of a city develop. The same model can be applied to enterprises for resource deployment, and applications are not merely limited to governments. [ABSTRACT FROM AUTHOR]

As network resources are shared between many users, resource management must be a key part of any communication system as it is needed to provide seamless communication and to ensure that applications and servers receive their required Quality-of-Service. However, mobile environments also need to consider handover issues. Furthermore, in a highly mobile environment, traditional reactive approaches to handover are inadequate and thus proactive techniques have been investigated. Recent research in proactive handover techniques defined two key parameters: Time Before Handover (TBH) and Network Dwell Time (NDT) for a mobile node in any given networking topology. Using this approach, it is possible to enhance resource management in common networks using probabilistic mechanisms because it is possible to express contention for resources in terms of No Contention, Partial Contention, and Full Contention. This proactive approach is further enhanced by the use of a contention queue to detect contention between incoming requests and those waiting for service. This paper therefore presents a new methodology to support proactive resource allocation for future networks such as Vehicular Ad-Hoc Networks. The proposed approach has been applied to a vehicular testbed and results are presented that show that this approach can improve overall network performance in mobile heterogeneous environments. [ABSTRACT FROM AUTHOR]

The problem of routing in ad hoc networks, in particular proactive routing, has attracted the attention of many researchers. Although the protocols proposed in the literature present some relevant characteristics, they also have their limitations, especially in terms of high number of mobile nodes or in terms of high number of load-dependent parameters of the ad hoc network which are often chosen intuitively by a seasoned expert. This paper describes our work to solve this difficult task using a multi-objective genetic algorithm to automate the selection process of the routing protocol parameters. The realized experiments showed the effectiveness of the proposed NGSA-II-OLSR compared to the original OLSR. In case of low node mobility, the proposed NSGA-II-OLSR improves the PLR between 8.59 and 33.17%; the E2ED between 18.17 and 27.56%; and the NRL between 35.18 and 36.60%. While in case of high mobility node, it improves the PLR between 3.47 and 9.94%; the E2ED between 1.47 and 9.40%; and the NRL between 0.14 and 2.34%. In addition, the algorithm can adapt the ad hoc network to each topology change which makes it adaptive to any environment changing. [ABSTRACT FROM AUTHOR]

Network clustering is the process of partitioning a network into a number of virtual entities mastered by certain nodes, called cluster centers that are responsible for collecting and maintaining topology information and managing the routing processes. In ad hoc networking, clustering has been introduced to deal with the dynamic topology by providing a temporarily stable network core. Clustering process mainly depends on the metric upon which the selection of cluster centers is performed. A wide range of clustering metrics were introduced in the literature based on network issues including mobility and connectivity degree, giving rise to a variety of clustering schemes. Although clustering provides energy consumption reduction, residual energy has not received enough attention and few studies have addressed the clustering on the basis of this feature. This paper discusses the current clustering metrics and proposes an energy-degree evaluation metric with mobility consideration taking into account the nodes residual energy and the network connectivity as two main keys of clustering. [ABSTRACT FROM AUTHOR]

The effective information interaction is important for drones to complete various tasks of flying ad hoc networks (FANETs). In this letter, we study the selection problem of transmission nodes and modes in dynamic FANETs. Besides classic direct transmission and relay transmission, drones can choose ferrying transmission opportunistically based on the given trajectory of other drones during the topology adjustment of swarms. To help multiple drones adjust the selection strategy with the topology changing, we design a dynamic matching game model, which takes both the current communication environment and resources that the future holds into account. Simulation results show that the proposed algorithm can effectively increase the system-wide throughput in the process of the adjustment. [ABSTRACT FROM AUTHOR]

Cognitive radio ad hoc network (CRAHN) has been considered an efficiently spectrum-aware communication paradigm in wireless networks because of its intrinsic properties of cognition and self-organization. In practice, because primary and secondary ad hoc networks are usually associated with two different types of wireless networks, the synchronization between primary users and secondary users is hardly guaranteed. The multi-channel asynchronous CRAHNs referred to as multi-channel non-time-slotted CRAHNs impose many challenging problems that severely degrade system performance. In this article, we review these challenging issues in multi-channel non-time-slotted CRAHNs, including reactivation- failure, frequently unexpected hand-offs, nonreal- time spectrum aggregation, inefficient power allocation, and frequent re-routing problems. Then, we develop a full-duplex based framework to resolve these issues. Future research directions are discussed to improve system performance of multi-channel non-time-slotted CRAHNs. [ABSTRACT FROM AUTHOR]

For a low-mobile Poisson bipolar network and under line-of-sight/non-line-of-sight (LOS/NLOS) path-loss model, we study repetitive retransmissions (RR) and blocked incremental redundancy (B-IR). We consider spatially-coded multiple-input multiple-output (MIMO) zero-forcing beamforming (ZFBF) multiplexing system, whereby the packet success reception is determined based on the aggregate data rate across spatial dimensions of the MIMO system. Characterization of retransmission performance in this low-mobile configuration is practically important, but inherently complex due to a substantial rate correlation across retransmissions and intractability of evaluating the probability density function of aggregate data rate. Adopting tools of stochastic geometry, we first characterize the rate correlation coefficient (RCC) for both schemes. Our results show that, compared to the RR scheme, the B-IR scheme has higher RCC while its coverage probability is substantially larger. We demonstrate that the spotted contention between coverage probability and RCC causes the mean transmission delay (MTD) of B-IR to become either smaller or larger than the MTD of the RR scheme. Finally, we develop a numerical approximation of MTD, and evaluate the effective spatial throughput (EST), which is reciprocal to MTD, of the RR and B-IR schemes. Our numerical results highlight fundamental tradeoffs between densification, multiplexing gain, block length, and activity factor of nodes. We further observe that for dense networks: first, LOS component is considerably instrumental to enhance EST; second, EST of the B-IR scheme can be much higher than that of the RR scheme; third, when Doppler spread exists, it can improve MTD of B-IR, whereas it does not cast any meaningful effect on MTD of RR. [ABSTRACT FROM AUTHOR]

We consider the ad-hoc networks consisting of $n$ wireless nodes that are located on the plane. Any two given nodes are called neighbors if they are located within a certain distance (communication range) from one another. A given node can be directly connected to any one of its neighbors, and picks its connections according to a unique topology control algorithm that is available at every node. Given that each node knows only the indices (unique identification numbers) of its one and two-hop neighbors, we identify an algorithm that preserves connectivity and can operate without the need of any synchronization among nodes. Moreover, the algorithm results in a sparse graph with at most $5n$ edges and a maximum node degree of 10. Existing algorithms with the same promises further require neighbor distance and/or direction information at each node. We also evaluate the performance of our algorithm for random networks. In this case, our algorithm provides an asymptotically connected network with $n(1+o(1))$ edges with a degree less than or equal to 6 for $1-o(1)$ fraction of the nodes. We also introduce another asynchronous connectivity-preserving algorithm that can provide an upper bound as well as a lower bound on node degrees. [ABSTRACT FROM AUTHOR]

Abstract Visible light communication (VLC) is a wireless technology complementary to well-understood radio frequency (RF) communication that is promising to help alleviate the spectrum crunch problem in overcrowded RF spectrum bands. While there has been significant advancement in recent years in understanding physical layer techniques for visible light point-to-point links, the core problem of developing efficient networking technology specialized for visible-light networks is substantially unaddressed. This article discusses the current existing techniques as well as the main challenges for the design of visible-light ad hoc networks - referred to as LANETs. The paper discusses typical architectures and application scenarios for LANETs and highlights the major differences between LANETs and traditional mobile ad hoc networks (MANETs). Enabling technologies and design principles of LANETs are analyzed and existing work is surveyed following a layered approach. Open research issues in LANET design are also discussed, including long-range visible light communication, full-duplex LANET MAC, blockage-resistant routing, VLC-friendly TCP and software-defined prototyping, among others. [ABSTRACT FROM AUTHOR]

Intermittently connected mobile networks are sparsely connected wireless ad-hoc networks where there is no end-to-end path from a source device to a destination. Generally, these paths do not exist. Hence, these devices use intermittent paths using the concept of store-and-forward mechanism to successfully accomplish the communication. These networks are featured by long delay, dissimilar data rates, and larger error rates. Hence, we look into the analysis of several delay-tolerant routing protocols, e.g., epidemic, spray-and-wait, prophet, maxprop, rapid, and spray-and-focus using opportunistic network environment simulator. At first, the investigations of the above considered routing protocols are done across three mobility models namely random direction, random walk, and shortest path map based (SPMB) movement model for node impact only. Then, we evaluate these routing protocols against the impacts of message copy, buffer, and time-to-live using SPMB movement model considering the results of node impact. We use three metrics, and the results show that spray-and-focus yields good performance for showing higher delivery, lower latency, and lower overhead among all routing techniques, while epidemic is poor. [ABSTRACT FROM AUTHOR]

Integration of Mobile ad hoc network (MANET) with the fixed Internet has paid immense attention in the field of heterogeneous networks. Such integration has many advantages and offer many usage scenarios for both MANET and the Internet. The MANET routing protocol ad hoc on-demand distance vector and dynamic source routing provide communication within the MANET. However, MANET router which desires communication with the Internet require global connectivity. This paper presents a survey of most significant proposals for MANET-Internet connectivity by describing their characteristics, evaluation metrics, quality parameters and approaches referred. The study of various gateway discovery and gateway selection schemes have been presented based on routing metrics, load balancing, adaptive technique, fuzzy system, address configuration and ant colony optimization approaches. Summary of significant contributions of existing schemes and issues found in literature for MANET-Internet connectivity have been presented. The survey concludes with additional investigation for future research work. [ABSTRACT FROM AUTHOR]

This paper studies the asymptotic properties of average area spectral efficiency (ASE) of a downlink cellular network in the limit of very dense base station (BS) and user densities. This asymptotic analysis relies on three assumptions: 1) interference is treated as noise; 2) the BS locations are drawn from a Poisson point process; and 3) the path loss function is bounded above satisfying mild regularity conditions. We consider three possible definitions of the average ASE, all of which give units of bits per second per unit bandwidth per unit area. When there is no constraint on the minimum operational signal-to-interference-plus-noise ratio (SINR) and instantaneous full channel state information (CSI) is available at the transmitter, the average ASE is proven to saturate to a constant, which we derive in a closed form. For the other two ASE definitions, wherein either a minimum SINR is enforced or CSI is not available, the average ASE is instead shown to collapse to zero at high BS density. We provide several familiar case studies for the class of considered path loss models, and demonstrate that our results cover most previous models and results on ultradense networks as special cases. [ABSTRACT FROM AUTHOR]

This paper studies the beneficial combination of wireless power transfer and millimeter-wave (mmWave) communications in wireless sensor networks. In particular, an mmWave wireless powered sensor network is considered, where the access point (AP) employs beamforming techniques to transfer energy to the sensors of a selected sector of the cell. The served sensors harvest and store energy from the received signal, and use it to power their uplink transmissions. We consider a random energy beamforming scheme but also propose several intelligent schemes that steer the beam to specific areas of the cell by considering the sensors’ locations. This setup is investigated from a large-scale point-of-view where spatial randomness is considered with the aid of Poisson point processes. The performance of the network is described in terms of the energy outage probability and the beam outage probability. We show that, depending on the scenario, each of the considered energy beamforming schemes can provide significant gains to the network’s performance. Finally, we study an event monitoring application of our theoretical framework, where the active sensors observe a random event in the network and the AP attempts to estimate it based on the received information; this scenario is evaluated in terms of the estimation’s mean squared error. [ABSTRACT FROM AUTHOR]

In this study, the authors address the problem of combining hierarchical and flat techniques to construct and maintain nodes' connectivity as well as links' symmetry (bidirectionality) in a wireless sensor network (WSN) comprising static nodes. They propose a localised and asynchronous self‐stabilising hybrid message passing a solution that seamlessly merges three well known connectivity control techniques for such ad hoc networks, namely k ‐hop clustering (k≥1), power control (transmission range adjustment) and sleep/wake scheduling. Their stigmergy‐based strategy (i.e. inspired from ants' pheromone‐based communication, division of labour and swarming behaviours) allows a WSN to simultaneously cope with issues such as scalability, fault tolerance, transmission range minimisation, energy hole problem (i.e. premature node deaths in the vicinity of the sink), channel overhearing and signalisation reduction. To the best of their knowledge, such a solution does not exist in the literature. The few self‐stabilising hybrid connectivity control protocols currently proposed use only two of the above‐mentioned techniques. The authors formally prove the correctness of their scheme and its self‐stabilisation property under an unfair distributed daemon. Simulation results show that the proposed scheme has a low average convergence time, is energy efficient and can prolong network lifetime. [ABSTRACT FROM AUTHOR]

Probabilistic flooding is commonly considered in vehicular ad-hoc networks (VANETs) to alleviate the celebrated broadcast storm problem. Heuristics and simulations have so far proved to be an efficient way with which to design probabilistic information dissemination solutions with demonstrated effectiveness. Supplementing with mathematical analysis for both design and evaluation is expected to generalize the results, and increase the confidence in the proposed solutions. So far, this has been limited due to the difficulties associated with the underlying stochastic dependencies. In this paper, we introduce simple models of single and multiple lane roads to design effective probabilistic flooding schemes for VANETs. The proposed analytical framework offers a novel and generic tool which can cover any number of lanes, vehicle transmission range, and density. We derive difference equations whose solutions yield the probability of all vehicles receiving the emergency warning message as a function of the rebroadcast probability, the number of neighbors of each vehicle, and the dissemination distance. The models are validated using simulations, realistically representing both the traffic and networking aspects, and are used as a baseline to design two schemes for information dissemination which employ probabilistic flooding. The one attempts direct calculation of the required parameters whereas the other adaptively regulates the rebroadcast probability based on the vehicle speed. The schemes are evaluated using simulations and are found to achieve significant performance improvements compared to blind flooding with respect to the achieved reachability, end-to-end delay, and number of rebroadcasts, comparable to the performance achieved by optimal flooding, obtained via brute force. [ABSTRACT FROM AUTHOR]

Multi-hop routing protocol in cognitive radio mobile ad hoc networks (CRMANETs) is a critical issue. Furthermore, the routing metric used in multi-hop CRMANETs should reflect the bands availability, the links quality, the PU activities and quality of service (QoS) requirements of SUs. For the best of our knowledge, many of researchers investigated the performance of the different routing protocols in a homogeneous environment only. In this paper, we propose a heterogeneous cognitive radio routing protocol (HCR) operates in heterogeneous environment (i.e. the route from source to destination utilize the licensed and unlicensed spectrum bands). The proposed routing protocol is carefully developed to make a tradeoff between the channel diversity of the routing path along with the CRMANETs throughput. Using simulations, we discuss the performance of the proposed HCR routing protocol and compare it with the AODV routing protocol using a discrete-event simulation which we developed using JAVA platform. [ABSTRACT FROM AUTHOR]

Traditional single-tiered wireless communications networks cannot scale to satisfy exponentially rising demand. Operators are increasing capacity by densifying their existing macro cell deployments with co-channel small cells. However, cross-tier interference and load balancing issues present new optimization challenges in channel sharing heterogeneous networks (HetNets). One-size-fits-all heuristics for allocating resources are highly suboptimal, but designing ad hoc controllers requires significant human expertise and manual fine-tuning. In this paper, a unified, flexible, and fully automated approach for end-to-end optimization in multi-layer HetNets is presented. A hill climbing algorithm is developed for reconfiguring cells in real time in order to track dynamic traffic patterns. Schedulers for allocating spectrum to user equipment are automatically synthesized using grammar-based genetic programming. The proposed methods for configuring the HetNet and scheduling in the time–frequency domain can address ad hoc objective functions. Thus, the operator can flexibly tune the tradeoff between peak rates and fairness. Far cell edge downlink rates are increased by up to 250% compared with non-adaptive baselines. Alternatively, peak rates are increased by up to 340%. The experiments illustrate the utility and future potential of natural computing techniques in software-defined wireless communications networks. [ABSTRACT FROM AUTHOR]

Content-centric networking (CCN) introduces a paradigm shift from a host centric to an information centric communication model for future Internet architectures. It supports the retrieval of a particular content regardless of the physical location of the content. Content caching and content delivery networks are the most popular approaches to deal with the inherent issues of content delivery on the Internet that are caused by its design. Moreover, intermittently connected mobile environments or disruptive networks present a significant challenge to CCN deployment. In this paper, we consider the possibility of using mobile users in improving the efficiency of content delivery. Mobile users are producing a significant fraction of the total Internet traffic, and modern mobile devices have enough storage to cache the downloaded content that may interest other mobile users for a short period too. We present an analytical model of the CCN framework that integrates a delay tolerant networking architecture into the native CCN, and we present large-scale simulation results. Caching on mobile devices can improve the content retrieval time by more than 50%, while the fraction of the requests that are delivered from other mobile devices can be more than 75% in many cases.

The traditional MAC protocol in ad hoc networks includes carrier sensing to judge the busy/idle state of a channel. However, in airborne tactical networks, the results of carrier sensing are usually inaccurate due to the wide distribution of nodes, large communication distance, and high-dynamic network topology, and the carrier sensing causes a large transmission delay and low channel utilization ratio. In this paper, we propose a novel channel busy recognition mechanism combined with auto regressive (AR) forecasting, namely, L-steps-revise AR (LS-AR). LS-AR predicts the number of bursts in the current time frame based on the number of bursts received in previous time frames, and the predicted number of bursts determines the channel busy/idle state. The difference between the predicted value and the true value serves as the means for correcting the next prediction. This mechanism avoids the delay caused by carrier sensing, improves the channel utilization ratio and provides a more accurate judgment to enable different priority packets to access a channel. The simulation results show that the algorithm can accurately predict the channel load and meet the requirements of the MAC protocol in airborne tactical networks.

It is well known that the stochastic nature of the interference deeply impacts the performance of emerging and future wireless communication systems. In this work we consider an ad hoc network where the nodes move according to the Random Waypoint mobility model. Assuming a time-varying wireless channel due to slow and fast fading and, considering the dynamic path loss due to the mobility of the nodes, we start by characterizing the interference distribution caused to a receiver by the moving interferers located in a ring. For this purpose, we consider a receiver located at the center of the simulated region. Based on the distribution of the interference’s power, we evaluate different methodologies to estimate the power of the interference in real-time. Results achieved with a Maximum Log-likelihood estimator (MLE) and a Probability Weighted Moments (PWM) estimator are compared. The accuracy of the results achieved with the proposed methodologies in several simulations show that they may used as an effective tool of interference power estimation in future wireless communication systems, exhibiting high accuracy even when the number of samples is low.