Search

Information-Centric Networks (ICN) are network architectures aiming at decoupling locator and identifier of contents, the primary objective of communication. It has been widely assumed that pervasive network caching and name-based forwarding, the most important characteristics of ICN, are beneficial in VANETs. However, these potential benefits have not been examined carefully enough to justify the shift from traditional routing design to ICN name routing and caching in VANETs. In this paper, we challenge this assumption and investigate the potential benefits of ICN in the VANET use case. We consider the two most important ICN-specific design options: caching policies and data source selection policies. Our results show that pervasive caching is indeed a major benefit of the ICN VANET while performance improvement of retrieving content from the nearest cache rather than from the original data producer is negligible, suggesting a return to legacy shortest path routing.

While geo-routing is a promising routing algorithm in urban vehicular ad-hoc networks (VANETs), there is still much work to be done for it to become truly usable for such environments. One of the biggest obstacles to this goal is the intermittent nature of VANETs due to mobility. Traditional geo-routing algorithms do not perform well in these conditions because they drop packets whenever they cannot find an immediate forwarder for the packet. In this paper, we propose RobustGeo, a routing protocol that combines the simplicity and efficiency of the greedy forwarding technique in geo-routing algorithms, with the robustness of delay tolerant networks in the face of disruptions in network connectivity. When there exists a good connection between the source and destination, RobustGeo can route the packet like the traditional geo-routing algorithms, and when the network faces disruptions, RobustGeo relies upon vehicle mobility and packet replication to explore multiple georoute paths and quickly recover the packet back to greedy forwarding. We show that for a highly intermittent scenario, RobustGeo has a delivery ratio of over 20% (compared to a pure geo-routing protocol's delivery ratio of 0), and it reduces delay by over 40% as compared to a more pure delay-tolerant routing solution.

In content-based mobile ad hoc networks (CB-MANETs), random linear network coding (NC) can be used to reliably disseminate large files under intermittent connectivity. Conventional NC involves random unrestricted coding at intermediate nodes. This however is vulnerable to pollution attacks. To avoid attacks, a brute force approach is to allow mixing only at the source. However, source restricted NC generally reduces the robustness of the code in the face of errors, losses and mobility induced intermittence. CB-MANETs introduce a new option. Caching is common in CB MANETs and a fully reassembled cached file can be viewed as a new source. Thus, NC packets can be mixed at all sources (including the originator and the intermediate caches) yet still providing protection from pollution. The hypothesis we wish to test in this paper is whether in CB-MANETs with replicated caches of a file, the performance (in terms of robustness) of the coding restricted to full caches equals that of unrestricted coding. In this paper, we examine and compare four options: unrestricted coding, full cache coding, source only coding, and no coding. As expected, we find that full cache coding remains competitive with unrestricted coding while maintaining full protection against pollution attacks.

This paper proposes a network-aware resource management scheme that improves the quality of experience (QoE) for adaptive video streaming in CDNs and Information-Centric Networks (ICN) in general, and Dynamic Adaptive Streaming over HTTP (DASH) in particular. By utilizing the DASH manifest, the network (by way of a logically centralized controller) computes the available link resources and schedules the chunk dissemination to edge caches ahead of the end-user's requests. Our approach is optimized for multi-rate DASH videos. We implemented our resource management scheme, and demonstrated that in the scenario when network conditions evolve quickly, our approach can maintain smooth high quality playback. We show on actual video server data and in our own simulation environment that a significant reduction in peak bandwidth of 20% can be achieved using our approach.

Recently, Information-Centric Network (ICN) has been attracting much attention with its promising future as next-generation Internet architecture. While ICN is scalable and efficient in Internet, concerns are raised when ICN is deployed in frequently-disruptive vehicular ad-hoc networks. In this paper, we introduce DT-ICAN, which provides low-cost, bandwidth efficient network operations to conquer disruptions while preserving the context awareness of ICN. We implement DTICANSIM, an open-source simulator for DT-ICAN in Qual Net. We evaluate the trade-off between the performance gain in data availability and the overhead due to epidemic dissemination using real-world traces. Our results show that DT-ICAN improves the file retrieval rate by 45% compared to traditional multi-hop ICN in real-world scenario, proving the necessity of providing an opportunistic networking option when end-to-end connectivity is unavailable for VANET ICN.

Information-centric networks have recently been drawing increasing attention in academia as well as in industry. Information and content retrieval is a critical service for mobile ad-hoc networks. It relies on other resources and tools, such as internal storage, content searching and sharing, delay-tolerant delivery, etc. Previous studies have shown that social networking can assist delay-tolerant routing design in many respects. In this paper, we specifically address content retrieval in delay-tolerant mobile ad-hoc networks. We propose a social-tie based content retrieval scheme to support the delay-tolerant MANET. The social hierarchy is structured using balanced connectivity criteria and a K-mean clustering algorithm. The proposed scheme has been evaluated and validated on a real social network dataset. Keywords—social network forwarding; information-centric network; delay-tolerant mobile ad-hoc network

Recently, Information Centric Networking (ICN) has attracted much attention also for mobiles. Unlike host-based communication models, ICN promotes data names as the first-class citizen in the network. However, the current ICN name-based routing requires Interests be routed by name to the nearest replica, implying the Interests are flooded in VANET. This introduces large overhead and consequently degrades wireless network performance. In order to maintain the efficiency of ICN implementation in VANET, we propose an opportunistic geo-inspired content based routing method. Our method utilizes the last encounter information of each node to infer the locations of content holders. With this information, the Interests can be geo-routed instead of being flooded to reduce the congestion level of the entire network. The simulation results show that our proposed method reduces the scope of flooding to less than two hops and improves retrieval rate by 1.42 times over flooding-based methods.

In this paper, we discuss scalable content-oriented routing that enables storing, sharing and searching data totally within the VANET. We introduce a proactive content discovery scheme, Hierarchical Bloom-Filter Routing (HBFR), to tackle mobility, large population and rich content challenges of VANETs. HBFR is compared to the popular ICN reactive content discovery scheme in practical VANET scenarios. The results show that HBFR suits non-sharable data services, while reactive ICN inspired content discovery works well with popular sharable data. We suggest a hybrid approach that adaptively utilizes proactive and reactive schemes for time-sensitive data in ICN VANET.

With the spread of mobile Internet, users have increased opportunities to retrieve content from the content producer via the application in mobile information-centric network. For security consideration, the content data must be encrypted and the content producer must be authenticated. Content data is signed by the producer and delivered to the requester via the public-key cryptography. A Certificate Authority (CA) generally verifies the binding between public-key and the producer identity. However, CA verification is not suitable in a mobile information-centric network where connection to a CA cannot be guaranteed. In this paper, we propose a social network based security scheme to verify the public-key and producer identity binding. The proposed scheme is evaluated on an artificial social network model first and is then validated on a real social network data.

First responders at the edge of the network rely on situation awareness updates to arrive in a timely matter, even when the fixed infrastructure is unavailable. The technical advancements of the commercial mobile phones make them capable of supporting such requirements under very disruptive network conditions. In this demo, we present a network architecture that exploits partial caches by utilizing network coding to deliver large files (e.g. images) to first responders. The architecture is based on a content centric network platform called ICEMAN(Information CEntric Mobile Ad-hoc Networking) and runs on Android phones. We demonstrate our system in a file dissemination scenario in a CORE/EMANE network emulation. We measure file delivery ratio, latency, and network overhead and report significant improvements that network coding achieves over fragmentation.

The advance of vehicle technology has brought to us the concept of Vehicle Cloud (VC). When Vehicle-to-Infrastructure (V2I) communications are unavailable, have failed or are too costly, Vehicle-to-Vehicle (V2V) communications fill the gap enabling VC services. In this paper, we discuss an important VC service, content-based routing, that allows future VC applications to store, share and search data totally within the Cloud. We review the critical issues of content discovery and forwarding in a content-based VC. Moreover, we introduce Bloom-Filter Routing (BFR), a proactive content discovery scheme for popular contents, to tackle the mobility and large content population challenges. BFR is compared to popular reactive content discovery schemes in practical VANET scenarios. The results show that proactive content discovery (i.e. BFR) suits non-sharable data, while reactive content discovery works well with popular sharable data. Consequently, we propose an adaptive hybrid approach that combines proactive and reactive strategies.

TCP over Mobile Ad-hoc Networks (MANETs) is challenging due to frequent route breaks, high random errors, and DATA-ACK interference. Network coded multipath approaches have been shown in several previous studies to be an effective transmission paradigms in disruptive networks. However, most of the previous studies either have no adaptive redundancy control or rely on theoretical models that require knowledge at all relays of the entire network state. In this paper, we propose a network coded multipath scheme for conventional TCPCodeMP that adapts to frequent link changes in MANET and requires no explicit control messages. The scheme exploits multiple-path redundancy and maintains total transparency to transport layer protocols. The proposed coding scheme is based on three components: (1) random linear coding scheme with adjustable redundancy, (2) multipath routing, (3) ACK Piggy coding. Simulation results show that in a 3-hop static scenario, the proposed multipath scheme improves TCP flows goodput by 70% compared to our previous single-path scheme. In an extreme MANET scenario where two TCP sessions co-exists and nodes are moving as fast as 25 m/s with up to 40% packet error rate (an environment in which regular TCP collapses completely), CodeMP achieves at least 700Kbps aggregate TCP goodput, with a Jain's fairness index of 0.99.

Network coding has attracted much attention in recent years due to the capability of transmission reduction and throughput improvement. In this paper, a redundancy-based delivery mechanism is proposed. This delivery mechanism utilizes network coding and linear combination on original packets to regenerate packets, which are called coded packets. Upon receiving a minimum number of coded packets, the destination can decode and get all original packets. Through theoretical analysis on delivery rate and overhead, we further propose an utility function to determine a proper redundancy degree and observe the suitable range of packet error rates to implement our delivery mechanism. Furthermore, the proposed delivery mechanism is applied to link adaptation. The simulation results show that by utilizing our proposed delivery, the operating SNR range of each PHY mode is lowered. In other words, when channel condition gets worse, one mobile device can still operate in the same PHY mode by utilizing the proposed delivery mechanism.

IEEE 802.16 Broadband Wireless Access system (BWA) is a promising emerging technology. In the IEEE 802.16 standard, multiple data transmission rates are defined by employing different modulation and channel coding schemes. How to select a proper mode affects the system performance significantly. In this paper, an efficient link adaptation scheme with QoS support is proposed. The proposed scheme takes both QoS demand and channel condition into consideration to determine a proper transmission mode. The QoS demand of a connection is represented as an expected packet error rate (PER). Based on this expected PER, the BS calculates the required signal-to-noise ratio (SNR) threshold of each mode. By comparing the measured SNR and all modes' SNR thresholds, the BS then suggests the SS a proper transmission mode. We evaluate the proposed scheme by simulations. The simulation results show that the link adaptation scheme improves the average system throughput and guarantees each connection's QoS demand.

IEEE 802.16 broadband wireless access system (BWA) is a promising emerging technology. In the IEEE 802.16 standard, multiple data transmission rates are defined by employing different modulation and channel coding schemes. How to select a proper mode affects the system performance significantly. In this paper, an efficient link rate adaptation algorithm, named QoS-aware link rate adaptation (Q-LRA), is proposed. Q-LRA takes both QoS demand and channel condition into consideration to determine the best mode. The QoS demand of a connection is represented as packet error rate (PER). Based on the specified PER, the BS calculates the required signal-to-noise ratio (SNR) threshold of each mode. By comparing the measured SNR and all modes' SNR thresholds, the BS suggests the SS the best mode. The performance of Q-LRA is evaluated by simulations. The simulation results show that Q-LRA improves system throughput and guarantees each connection's QoS demand.