The purpose of this work is to present realistic behaviour of Slotted Aloha (S-ALOHA), used as Request Access Channel (RACH), with good performance regarding stability, efficiency, delay and capacity of traffic control. We present modelling and simulation of those parameters, which most influence the performance in terms of stability, and efficiency of the MAC technique based on S-Aloha. Consid...

The aim of this paper is to study the Aloha medium access (MAC) scheme in one-dimensional, linear networks, which might be an appropriate assumption for Vehicular Ad-hoc NETworks (VANETs). We study performance metrics based on the signal-over-interference and noise ratio (SINR) assuming power-law mean path-loss and independent point-to-point fading. We derive closed formulas for the capture pro...

Based on a stochastic geometry framework, we establish an analysis of the multi-hop spatial reuse aloha protocol (MSR-Aloha) in ad hoc networks. We compare MSR-Aloha to a simple routing strategy, where a node selects the next relay of the treated packet as to be its nearest receiver with a forward progress toward the final destination (NFP). In addition, performance gains achieved by employing ...

The stability of slotted ALOHA systems with various types of capture phenomena and multiple packet reception capability is discussed in conjunction with the cusp catastrophe. The slotted ALOHA systems considered are classified into; 1) single packet reception with geometric capture, 2) independent multiple packet reception with geometric capture, 3) single packet reception with M -out-of-N capt...

The collision of ID signals from a large number of colocated passive RFID tags is a serious problem; to realize a practical RFID systems we need an effective anti-collision algorithm. This letter presents an adaptive algorithm to minimize the total time slots and the number of rounds required for identifying the tags within the RFID reader’s interrogation zone. The proposed algorithm is based o...

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...

Last lecture, we looked at the ALOHA protocol for medium access control (MAC). The ALOHA protocol pioneered two main ideas: the ability to detect and handle collisions on a shared medium and the use of randomization to decide whether to transmit a packet or not. However, ALOHA was designed for situations where none of the users could hear any of the other users transmitting. Real-world wireless...

Broadcast MAC (BMAC) is simple yet very efficient MAC protocol for Underwater Wireless Sensor Network (UWSN). BMAC senses the channel and if channel is free then data is transmitted. It is much desired protocol for some low traffic networks. Here we carry out its evaluation. We also evaluate ALOHA protocol which is also for UWSN. There are various versions of ALOHA protocol available but here w...

Radio frequency identification systems with passive tags dramatically increase the ability of an organization to acquire a vast array of data about the location and properties of any entity that can be physically tagged and wirelessly scanned within certain technical limitations. However, if multiple tags are to be identified simultaneously, messages from the tags can collide and cancel each ot...