Information-centric mobile caching network frameworks and caching optimization: a survey <s> Caching Framework based on Hybrid Network <s> This paper involves the study of the throughput capacity of hybrid wireless networks. A hybrid network is formed by placing a sparse network of base stations in an ad hoc network. These base stations are assumed to be connected by a high-bandwidth wired network and act as relays for wireless nodes. They are not data sources nor data receivers. Hybrid networks present a tradeoff between traditional cellular networks and pure ad hoc networks in that data may be forwarded in a multihop fashion or through the infrastructure. It has been shown that the capacity of a random ad hoc network does not scale well with the number of nodes in the system. In this work, we consider two different routing strategies and study the scaling behavior of the throughput capacity of a hybrid network. Analytical expressions of the throughput capacity are obtained. For a hybrid network of n nodes and m base stations, the results show that if m grows asymptotically slower than √n, the benefit of adding base stations on capacity is insignificant. However, if m grows faster than √n, the throughput capacity increases linearly with the number of base stations, providing an effective improvement over a pure ad hoc network. Therefore, in order to achieve nonnegligible capacity gain, the investment in the wired infrastructure should be high enough. <s> BIB001 </s> Information-centric mobile caching network frameworks and caching optimization: a survey <s> Caching Framework based on Hybrid Network <s> Hybrid networks consisting of MANET nodes and cellular infrastructure have been recently proposed to improve the performance of military networks. Prior work has demonstrated the benefits of in-network content caching in a wired, Internet context. We investigate the problem of developing optimal routing and caching policies in a hybrid network supporting in-network caching with the goal of minimizing overall content-access delay. Here, needed content may always be accessed at a back-end server via the cellular infrastructure, alternatively, content may also be accessed via cache-equipped "cluster" nodes within the MANET. To access content, MANET nodes must thus decide whether to route to in-MANET cluster nodes or to back-end servers via the cellular infrastructure, the in-MANET cluster nodes must additionally decide which content to cache. We model the cellular path as either i) a congestion-insensitive fixed-delay path or ii) a congestion-sensitive path modeled as an M/M/1 queue. We demonstrate that under the assumption of stationary, independent requests, it is optimal to adopt static caching (i.e., To keep a cache's content fixed over time) based on content popularity. We also show that it is optimal to route to in-MANET caches for content cached there, but to route requests for remaining content via the cellular infrastructure for the congestion-insensitive case and to split traffic between the in-MANET caches and cellular infrastructure for the congestion sensitive case. We develop a simple distributed algorithm for the joint routing/caching problem and demonstrate its efficacy via simulation. <s> BIB002 </s> Information-centric mobile caching network frameworks and caching optimization: a survey <s> Caching Framework based on Hybrid Network <s> This article introduces the idea of ICN-enabled IEEE 802.11 wireless access points (APs) as nano data centers. After elaborating its design, we evaluate the performance with trace-based simulation and prototype-based experiment. The evaluation shows that even a small size cache, e.g. 1Gbyte nearby mobile users can reduce traffic load by 15%, which enables mobile operators to reduce operational cost in the mobile back-haul areas. Moreover, a mobile user can download content files with less delay and interruption, especially when the performance of network becomes degraded or unstable. The synergy between ICN supporting mobility as the norm and widely deployed broadband IEEE 802.11 wireless access points makes this proposal attractive as a potential application scenario for ICN. <s> BIB003 </s> Information-centric mobile caching network frameworks and caching optimization: a survey <s> Caching Framework based on Hybrid Network <s> High-quality multimedia streaming services in Vehicular Ad-hoc Networks (VANETs) are severely hindered by intermittent host connectivity issues. The Information Centric Networking (ICN) paradigm could help solving this issue thanks to its new networking primitives driven by content names rather than host addresses. This unique feature, in fact, enables native support to mobility, in-network caching, nomadic networking, multicast, and efficient content dissemination. In this paper, we focus on exploring the potential social cooperation among vehicles in highways. An ICN-based COoperative Caching solution, namely ICoC, is proposed to improve the quality of experience (QoE) of multimedia streaming services. In particular, ICoC leverages two novel social cooperation schemes, namely partner-assisted and courier-assisted, to enhance information-centric caching. To validate its effectiveness, extensive ns-3 simulations have been executed, showing that ICoC achieves a considerable improvement in terms of start-up delay and playback freezing with respect to a state-of-the-art solution based on probabilistic caching. <s> BIB004 </s> Information-centric mobile caching network frameworks and caching optimization: a survey <s> Caching Framework based on Hybrid Network <s> In this paper, we investigate content-centric data transmission in the context of short opportunistic contacts and base our work on an existing content-centric networking architecture. In case of short interconnection times, file transfers may not be completed and the received information is discarded. Caches in content-centric networks are used for short-term storage and do not guarantee persistence. We implemented a mechanism to extend caching on persistent storage enabling the completion of disrupted content transfers. The mechanisms have been implemented in the CCNx framework and have been evaluated on wireless mesh nodes. Our evaluations using multicast and unicast communication show that the implementation can support content transfers in opportunistic environments without significant processing and storing overhead. <s> BIB005 </s> Information-centric mobile caching network frameworks and caching optimization: a survey <s> Caching Framework based on Hybrid Network <s> We present testbed experiments of multi-source mobile video streaming that jointly exploits mobility and throughput prediction to prefetch video data in caches located at hotspots that the mobile will encounter and device-to-device (D2D) communication to opportunistically obtain parts of a video from neighboring mobile devices. A contribution of this paper includes a procedure to efficiently utilize multirate Wi-Fi links, which can be legacy Wi-Fi hotspot links and device-to-device links using Wi-Fi direct. <s> BIB006 </s> Information-centric mobile caching network frameworks and caching optimization: a survey <s> Caching Framework based on Hybrid Network <s> D2D offloading reduces the load of cellular network by asking mobile nodes to download content directly from storage of neighboring helpers via short range links. In this paper, we introduce a novel storage assignment scheme that can enhance storage utilization for D2D networks that have different types of storage nodes. Unlike traditional D2D systems that only use storage as static content cache, our scheme uses on-demand relaying to enhance storage utilization. Our on-demand relaying scheme replicates rare content when it is requested. Therefore, the proposed scheme can greatly increase the amount of content supported by the offloading system. We develop a convex optimization based algorithm to find the optimal storage assignment tradeoff between static caching and on-demand relaying. Numerical results and real-world trace-driven simulations show that our algorithm can achieve 30% reduction in offloading failure rate compared to static schemes. <s> BIB007
WAHN is appealing in many places such as battlefields and disaster areas, because mobile nodes are available to communicate in a multi-hop manner without infrastructure. However, with the aim to cover a wider area with less fixed infrastructure, sometimes WAHN combining with infrastructural network is a useful approach to form a hybrid network BIB001 . A typical solution of the hybrid networks is composed of MANET nodes and cellular infrastructural networks, which constructs hybrid networks supporting both mobile cellular communication and ad hoc communication. Besides the hybrid network of cellular and ad hoc network mentioned above, usually, the typical hybrid networks involve hybrid network based on cellular network and WLAN/D2D, hybrid network based on ICN and ad hoc network (ICMANET), etc. Projects related include I-CAN, UMOBILE, RIFE, and, GreenICN etc. BIB006 11, 12,  . Figure 4 presents the typical caching framework based on hybrid networks, in which caches are placed in MBSs, SBSs, APs and user devices in radio access networks. In this section, research issues on caching enabled hybrid network are addressed. I-CAN is presented to advance the integration of cellular (licensed spectrum) and wireless (license-exempt) access technologies in   . In I-CAN, proactive caching exploiting mobility and content prediction, innetwork caching and replication, multipath/multisource transport and traffic engineering are investigated in integrated cellular and Wi-Fi networks. A cache-enabled hybrid network is formed by cellular network and autonomous nodes in military network BIB002 . In the hybrid network, the back-end server cache all the needed content, the in-MANET cluster nodes are equipped with caches and decide which content to cache. On the one hand, back-end server can provide the requested contents via the cellular network; on the other hand, cluster nodes may offer the contents. As IEEE802.11 supports massive throughput and high transmission rate, and IEEE802.11 APs are widely deployed without additional infrastructure, most mobile devices are equipped with IEEE 802.11 series. The idea of ICN-enabled IEEE 802.11 wireless APs as nano data centers is introduced to reduce traffic load and operational cost BIB003 . In BIB007 , a caching framework is addressed combining a cellular network and an opportunistic network of D2D communication. The cellular network provides pervasive network coverage and a global communication channel for all mobile nodes and it is mainly used for control message exchange. Content delivery traffic is offloaded through D2D communication between nearby mobile nodes to reduce content delivery cost. The links used for D2D communication can be Wi-Fi Direct, Bluetooth, LTE/LTE-A, etc. Seeds and relays are chosen as helpers to contribute their storage as content caches and allow other nodes to download content from their caches through D2D links. In BIB004 , an ad hoc based caching framework integrated with NDN is proposed in the highway VANET scenario by using ad hoc Wi-Fi 802.11a, and NDN stack is installed in each vehicle and RSU. A highway-customized ICN-based cooperative caching mechanism named ICoC is provided aiming at maximizing video playback quality without excessive startup delay and minimizing the playback freezing ratio. In BIB005 , content-centric data transmission is investigated in the context of short opportunistic contacts based on CCNx framework content-centric networking architecture in wireless mesh network. All of the literatures above indicate that mobile caching network frameworks can be distinguished in network type and cache location. Based on the research on information centric mobile caching frameworks mentioned, a summary on the main research issues is provided in Table 1 .