We analyze the throughput, delay and energy efficiency performance of space diversity slotted ALOHA when multibeam smart antenna arrays, capable of steering the beams selectively on smaller sectors, are used at the base station receiver. Analytical expressions to establish the effect of diITerent beamwidths, number of beams, beam steering patterns, and beam service times on the achieved perform...

—Multi-hop underwater acoustic sensor networks constrain the performance of medium access control protocols. The efficiency of the well-known RTS-CTS scheme is degraded due to long propagation delays of such networks. Recently, interest in Aloha variants has surfaced; however, the performance of such protocols within the context of multi-hop networks is not well studied. In this paper, we ident...

Silvano Pupolin , Luciano Tomba , Michele Zorzi Dipartimento di Elettronica e Informatica, University of Padova Via G. Gradenigo 6/A, I-35131 Padova (Italy) Dipartimento di Elettronica e Informazione, Politecnico of Milano Piazza Leonardo da Vinci 32, I-20133 Milano (Italy) Abstract—The actual trend towards Personal Communication Systems suggests to devote considerable research efforts to find ...

Random packet CDMA (RP-CDMA) is a recently proposed random transmission scheme which has been designed from the beginning as a cross-layer method to overcome the restrictive nature of the Aloha protocol. Herein, we more precisely model its performance and investigate throughput and network stability. In contrast to previous works, we adopt the spread Aloha model for header transmission, and the...

We perform a new analysis of the performance of the wide-band code-division multiple access (W-CDMA) randomized slotted-offset random access channel with Nakagamifading and compare it with the performance of a comparable randomized slotted-ALOHA-based random access channel. In a previous paper, it was shown through simulations that the W-CDMA random access channel is fast, robust, and simple to...

Satellites are going to revolutionize the Internet of Things (IoT) connectivity enabling ubiquitous coverage targeted by 5G and upcoming 6G networks. While potentials satellite IoT unquestionable, many challenges still remain unsolved. In present work, we design a Long Range Wide Area Network (LoRaWAN) with mobile gateways (GWs) installed on Low Earth Orbit (LEO) satellites. We address synchron...

In this paper, we present a frame structure that can be viewed as preamble for the detection and synchronization process (leading to low cost receiver) an encoded codeword carrying transmitted message reliable transmission). This duality facilitates ALOHA protocol avoiding overhead. The structure, named Quasi-Cyclic Short Packet (QCSP), is based on association of Cyclic Code Shift Keying (CCSK)...

While the Internet of Things continues to grow, LoRaWAN standard is generating special interest due its open-source nature, ultralow-power consumption and long-range connectivity. Recent works have explored challenges implementing LoRaWAN, with scalability being considered one major bottlenecks imposed by Aloha-based medium access control (MAC) layer. Despite much on-going research on schedulin...

This paper studies resource reservation mechanisms that can be incorporated into distributed multi{path Quality{of{Service (QoS) routing algorithms. Three resource reservation schemes, the forward reservation scheme, the backward reservation scheme and the hybrid reservation scheme, are investigated. Protocols that combine these resource reservation schemes with a ticket{based distributed QoS r...

ABERDEEN 29 s Aberdeen Research and Development Center AFETR s Air Force Eastern Test Range AFGWC see GWC ALOHA 35 i Aloha Network, University of Hawaii ALOHA-TIP 163 s Aloha Network, University of Hawaii AMEC see Belvoir AMES-67 16 NASA Ames Research Center AMES-ILLIAC see ILLIAC AMES-TIP 144 NASA Ames Research Center ARPA-TIP 156 Advanced Research Projects Agency BBN 1D 197 Bolt Beranek and N...