Computer Networks 105 (2016) 207–223 Contents lists available at ScienceDirect Computer Networks journal homepage: www.elsevier.com/locate/comnet Relay-based multipoint content delivery for wireless users in an information-centric network Pantelis A. Frangoudis a,∗ , George C. Polyzos b , Gerardo Rubino a a IRISA/INRIA Rennes-Bretagne Atlantique, Campus de Beaulieu, 35042 Rennes, France b Mobile Multimedia Laboratory, Athens University of Economics and Business, 11362 Athens, Greece a r t i c l e i n f o Article history: Received 24 November 2015 Revised 25 April 2016 Accepted 4 June 2016 Available online 11 June 2016 Keywords: Wireless LAN Information-centric networking Multi-objective optimization Quality of experience a b s t r a c t Information-Centric Networking (ICN) reconsiders the host-centric Internet paradigm with a view to in- formation or content-based identifiers and where multicast data delivery is the norm. However, Wi-Fi, the predominant means of local wireless connectivity today, but also 3G and 4G technologies, are known to suffer from poor multicast performance. In this work, we consider exploiting content awareness, which is inherent in ICN architectures, to improve wireless multicast delivery by means of relaying. In partic- ular, given that different types of content have different performance requirements, we provide a multi- objective optimization formulation for the problem of activating appropriate subsets of users as relays and deciding on their transmission rates, optimizing for different criteria, such as reliability, performance, and energy cost on a per-content item basis. Based on that, we propose a heuristic algorithm to select relay-rate assignments, showing it to outperform standard wireless multicast transmission strategies and also to be feasible to operate on top of resource-constrained off-the-shelf wireless equipment. Finally, we demonstrate how our scheme could be utilized for multicasting scalable video with improved Quality of Experience. © 2016 Elsevier B.V. All rights reserved. 1. Introduction In recent years, there has been a push towards “clean-slate” information-centric Internet architectures, where named data, in- stead of named hosts are the core of the new communication paradigm. This shift was motivated by the observation that the Internet architecture has not changed fundamentally since its in- ception, but user (stakeholder) behavior and application demands have all dramatically been altered. Much of the traffic nowadays involves content dissemination via CDNs or proxies, which mediate communication between content publishers and consumers, plac- ing focus on the information itself, rather than on the communi- cation endpoints. At the same time, with the low cost and high speed of wireless technologies for the home network and the pro- liferation of mobile devices with wireless networking capabilities, much of this information is delivered to users over wireless links. Our work is put in the context of the Publish-Subscribe Internet (PSI) architecture [1,2]. PSI approaches information-centrism by ap- plying the publish/subscribe principle at all networking layers. The main PSI entities are publishers and subscribers and their commu- ∗ Corresponding author. E-mail addresses: pantelis.frangoudis@inria.fr (P.A. Frangoudis), polyzos@aueb.gr (G.C. Polyzos), gerardo.rubino@inria.fr (G. Rubino). nication is brokered by special rendezvous nodes. PSI and ICN in general has various advantages and features such as built-in sup- port for caching and mobility [3], multihoming, multipath, and se- curity [4]. We focus on a networking scenario where multiple users within a Wi-Fi cell subscribe to common content items, which are even- tually multicast to them. This could be the case, e.g., for mul- tiple users in a home wireless network watching the same In- ternet TV program simultaneously from different terminals, or users in a campus Wi-Fi network viewing video lectures. How- ever, IEEE 802.11 was not designed for such scenarios, where mul- ticast/broadcast traffic dominates [5]; the backoff window is never increased, since there are no acknowledgments for broadcast pack- ets, and typically the transmission rate is lower compared to the rate for unicast packets, in order to achieve more reliable delivery for low-rate users. Our work builds on the premise that, in the content-centric PSI model, with awareness of the performance requirements of dif- ferent content items, we can flexibly pick specific clients to act as relays for other co-subscribers whose connection with the Ac- cess Point (AP) is of worse quality. Thus, instead of a single mul- ticast transmission at a low rate, multiple multicast transmissions of the same content at a higher rate can take place. If relay se- lection is careful, both throughput and reliability advantages are http://dx.doi.org/10.1016/j.comnet.2016.06.004 1389-1286/© 2016 Elsevier B.V. All rights reserved.