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Energy Efficient Opportunistic Uplink Packet Forwarding in Hybrid Wireless Networks
Get PDFOpportunistic schedulers have been primarily proposed to enhance capacity of cellular networks. However, little is known about opportunistic scheduling with fairness and energy efficiency constraints. In this work, we show that adapting opportunistic scheduling can dramatically amelio- rate energy efficiency for uplink transmissions, while achiev- ing near-optimal throughput and high fairness. To achieve this goal, we propose a novel two-tier uplink forwarding scheme in which users cooperate, in particular by forming clusters of dual-radio mobiles in hybrid wireless networks.EUTRUEpu
On the Complexity of the Regenerator Location Problem - Treewidth and Other Parameters
No full textWe deal with the Regenerator Location Problem in optical networks. We are given a network G = (V, E), and a set Q of communication requests between pairs of terminals in V. We investigate two variations: one in which we are given a routing P of the requests in Q , and one in which we are required to find also the routing. In both cases, each path in P must contain a regenerator after every d edges in order to deal with loss of signal quality for some d > 0. The goal is to minimize the number of vertices that contain regenerators used by the solution. Both variations of the problem are \textscNP−hard in the general case. In this work we investigate the parameterized complexity of the problem. We introduce several fixed parameter tractability results and polynomial algorithms for fixed parameter values, as well as several \textscNP−hardness results. The parameters under consideration are the treewidth of the input graph, the sizes d and |Q| and the vertex load, i.e. the maximum number of paths passing through any vertex.TRUEpu
WiFi Direct and LTE D2D in Action
Get PDFWith the evolution of high-performance multi-radio smartphones, Device-to-Device (D2D) communications became an attractive solution for enhancing the performance of cellular networks. Although D2D communications have been widely studied within past few years, the majority of the literature is confined to new theoretical proposals and did not consider implementation challenges. In fact, the implementation feasibility of D2D communications and its challenges are still a relevant research question. In this paper, we introduce a protocol that focuses on D2D communications using LTE and WiFi Direct technologies. We also show that currently available WiFi Direct features permits to deploy the D2D paradigm on top of the LTE cellular infrastructure, without requiring any fundamental change in LTE protocols.TRUEpu
The costs and benefits of combining different IP mobility standards
No full textSeveral IP mobility support protocols have been standardized. Each solution provides a specific functionality and/or requires operations of particular nodes. The current trend is towards the co-existence of these solutions, though the impact of doing so has not been yet fully understood. This article reviews key standards for providing IP mobility support, the functionality achieved by combining them, and the performance cost of each combination in terms of protocol overhead and handover latency. We show that combining different mobility mechanisms has a non-negligible cost. Finally we identify a strategy for combining mobility protocols and properties that facilitate this combination.TRUEpu
Profit Maximization in Flex-Grid All-Optical Networks
Get PDFPublished as part of the Book "Structural Information and Communication Complexity", 20th International Colloquium, SIROCCO 2013, Ischia, Italy, July 1-3, 2013, Revised Selected Papers
DOI: 10.1007/978-3-319-03578-9_21All-optical networks have been largely investigated due to their high data transmission rates. The key to the high speeds in alloptical networks is to maintain the signal in optical form, to avoid the overhead of conversion to and from electrical form at the intermediate nodes. In the traditional WDM technology the spectrum of light that can be transmitted through the optical fiber has been divided into frequency intervals of fixed width with a gap of unused frequencies between them. In this context the term wavelength refers to each of these predefined frequency intervals.
An alternative architecture emerging in very recent studies is to move towards a flexible model in which the usable frequency intervals are of variable width. Every lightpath is assigned a frequency interval which remains fixed through all the links it traverses. Two different lightpaths using the same link have to be assigned disjoint sub-spectra. This technology is termed flex-grid or flex-spectrum.
The introduction of this technology requires the generalization of many optimization problems that have been studied for the fixed-grid technology. Moreover it implies new problems that are irrelevant or trivial in the current technology. In this work we focus on bandwidth utilization in path topology and consider two wavelength assignment, or in graph theoretic terms coloring, problems where the goal is to maximize the total profit. We obtain bandwidth maximization as a special case.TRUEpu
On providing mobility management in WOBANs: Integration with PMIPv6 and MIH
Get PDFThe Wireless-Optical Broadband Access Network(WOBAN) is a promising access architecture that combines the high performance of optical networks with the ubiquity and convenience of wireless technologies. This article proposes a network based mobility framework that is specially tailored for WOBANs. The proposed architecture is based on Proxy Mobile IPv6 and IEEE 802.21 mobility management protocols, but it also defines a number of optimizations that enable the seamless handover of mobile nodes. In particular, the hierarchical architecture together with the broadcast-and-select nature of the optical part of the WOBAN are leveraged to: i) optimize the mobility of users with respect to the overall network resources, both at the wireless access and optical distribution parts, ii) remove the overhead of IP-in-IP tunneling between the PMIPv6 entities, and iii) perform an efficient bicasting during the handover process to minimize packet loss.TRUEpu
Is the Network Capable of Computation?
Get PDFEnsuring correct network behavior is hard. Previous
state of the art has demonstrated that analyzing a network
containing middleboxes is hard. In this paper, we show that
even using only statically configured switches, and asking the simplest possible question – “Will this concrete packet reach the destination?” – can make the problem intractable. Moreover, we demonstrate that this is a fundamental property because a network can perform arbitrary computations. Namely, we show how to emulate the Rule 110 cellular automaton using only basic network switches with simple features such as packet matching, header rewriting and round-robin load balancing. This ultimately means that analyzing dynamic network behavior can be as hard as analyzing an arbitrary program.TRUEpu