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This paper is focused on data transmission scheduling in V2I communications, where a central station, the roadside beacon, decides how to allocate system resources among the vehicles under coverage. We consider non-safety applications, whose commercial appeal is expected to accelerate the deployment of VANETs. In this case, the main objective is to deliver(More)
Automatic identification based on radio frequency identification (RFID) is progressively being introduced into industrial environments, enabling new applications and processes. In the context of communications, RFID rely mostly on Frame Slotted Aloha (FSA) anticollision protocols. Their goal is to reduce the time required to detect all the tags within range(More)
—In Cooperative Automatic Repeat reQuest (C-ARQ) protocols, the retransmission process between a pair of nodes can be assisted by a relay node. We investigate the performance of C-ARQ algorithms in cellular access networks, where the use of relays is a promising strategy for future evolutions. By means of Markov analysis and simulation we show that the(More)
TCP, the dominant transport protocol for Internet applications, suffers severe performance degradation due to packet losses when a wireless link is present in the end-to-end path. For this reason, the 3G specification entity, 3GPP, has defined a reliable link layer protocol, RLC, to support packet switched services over UMTS. RLC provides error recovery in(More)
Keywords: Radio frequency identification Frame slotted ALOHA Equilibrium point analysis Stability Discrete time system Tag loss ratio a b s t r a c t In many practical RFID applications tags are attached to items that pass through the read-er's field moving at a constant speed, following a fixed path. The time-constrained presence of the tags in the(More)
—RFID systems implementing Dynamic Frame Slotted Aloha (DFSA) can adjust the number of identification rounds (slots) within an inventory cycle (frame). The usual approach to reduce the identification time of the tag population is to select the frame size attaining the highest throughput in the frame. However, it is more accurate to minimize the(More)
—We consider a spectrum leasing system in which secondary networks offer offload services to a primary network (PN) in exchange for temporary access to the PN's spectrum. When the coverage areas of several secondary access nodes (SANs) overlap, they compete for primary users (PUs), which benefits the PN, except when the SANs collude and coordinate their(More)
—Cooperative inter-vehicular applications rely on the periodic exchange of broadcast single-hop status messages among vehicles, called beacons. The aggregated load on the wireless channel due to beacons can prevent the transmission of other types of messages, what is called channel congestion due to beaconing activity. In this paper we propose a novel(More)
In dense radio frequency identification (RFID) systems, reader-to-reader interference may appear among readers operating nearby. When the anticollision algorithm is Frame Slotted Aloha (FSA), a usual solution is to multiplex the frames of interfering readers by means of a central controller. The scenario studied considers RFID tags attached to objects(More)