This chapter is about alternative MAC solutions for VANETs, based on a synchronous, slotted philosophy. After highlighting the limitation of the incumbent CSMA/CA solution, the chapter explains the rationale for a slotted standard and briefly introduces the three solutions found in literature (namely MS-Aloha, D-TDMA and STDMA). In particular, one of them, MS-Aloha, seems particularly rich in f...

Simultaneous random access of massive machine type communications (MTC) devices are expected to cause congestion in the radio access network. Not only the performance of MTC, but the coexisting human to human (H2H) communications would also degrade dramatically without an appropriate medium access control (MAC) protocol. However, most existing solutions focus on the random access procedure with...

To enhance the throughput of a slotted random access protocol in a radio communication system, we describe the use of a scheme in which multiple power levels are used at the transmitters. We first consider a situation in which n transmitters are simultaneously trying to send a packet to a central receiving station using a time-slotted access protocol, like slotted ALOHA. Each of these transmitt...

LoRaWAN is one of the new and updated standards for IoT applications. However, the expected high density of peripheral devices for each gateway, and the absence of an operative synchronization mechanism between the gateway and peripherals, all of which challenges the networks scalability. In this paper, we propose to normalize the communication of LoRaWAN networks using a Reservation-ALOHA (R-A...

The rapid technological advances and innovations of the past few decades have pushed wireless communication from concept to reality. The popularity of wireless communication systems can be seen almost everywhere in the form of cellular networks, WLANs, and WPANs. Packet-switched technology has been demonstrated as effective in cellular radio systems with short propagation delay, not only for da...

This paper investigates the energy efficiency of RFID anti-collision protocols and their suitability for use in RFID-enhanced wireless sensor networks (WSNs). We present a detailed analytical methodology and an in-depth qualitative and quantitative energy consumption analysis of Pure and Slotted Aloha anti-collision protocols and their variants. We find that Slotted Aloha variants that employ m...

A new multichannel MAC protocol called Hop Reservation Multiple Access (HRMA) for packet-radio networks is introduced, specified and analyzed. HRMA is based on very-slow frequencyhopping spread spectrum (FHSS) and takes advantage of the time slotting necessary for frequency hopping. HRMA allows a pair of communicating nodes to reserve a frequency hop (channel) using a hop reservation and handsh...

Gain division multiple access (GDMA) is a non-orthogonal (NOMA) technique for uplink communications. In GDMA, the receiver employs both magnitudes and phases of channel gains associated to users separate users. power-domain NOMA, power levels users.We apply GDMA concept together with orthogonal frequency (OFDM) combat collision problem in ALOHA system. Our goal minimize complexity devices (user...

We investigate the effect of limiting the number of retransmission trials on the stability of slotted ALOHA systems with no capture effect. Using an argument of the catastrophe theory, we prove that a slotted ALOHA system is mono-stable, if the number of retransmission trials is limited to, at most, eight. We also show how the bistable region is enlarged, as the number of retransmission trials ...