Cognitive medium access control protocols for secondary users sharing a common channel with time division multiple access primary users

Abstract

The unused time slots in a primary time division multiple access (TDMA) network are regarded as the potential channel access opportunities for secondary users (SUs) in cognitive radio (CR). In this paper, we investigate the medium access control protocols that enable SUs to access a common TDMA channel with primary users (PUs). The primary traffic is assumed to follow a Bernoulli random process. A two‐state Markov chain is used to model the secondary traffic, and two different scenarios are considered. The first scenario assumes that the secondary packet arrivals are independent and follow a Bernoulli random process and a cognitive carrier sensing multiple access (Cog‐CSMA) protocol is proposed. A Rayleigh fading channel is considered in evaluating Cog‐CSMA, and its throughput expression is derived in this paper. The second scenario assumes that the packet arrivals follow a correlated packet arrival process and a cognitive packet reservation multiple access (Cog‐PRMA) protocol is proposed. A Markov chain is used to model the different system states in Cog‐PRMA and derive the throughput. Numerical results show that the Cog‐CSMA and Cog‐PRMA protocols achieve the objective of supporting secondary transmissions in a TDMA network without interfering the PUs' transmissions and improve the network bandwidth utilization. Copyright © 2012 John Wiley & Sons, Ltd.

Memory and memoryless optimal time-window controllers for secondary users in vehicular networks

“…Specifically, about the (actually, quite intuitive) behaviour of the optimal access controller (14), we see that when the access is allowed (i.e., when the secondary-access decision A i (t) = 1 is taken/satisfied) the serving RSU (i) enables to upload data only the VC which maximizes the weighted utility acquired by the network, regardless of the controller class of interest (Hard/Soft, Memory/Memoryless). Before to address the general problem (15), let us spend some words to present two important limit cases.…”

“…Proposition 2: Under the above reported assumptions, for the HATWOP, the access time-windows are optimally allotted by the serving RSU (i) according to (14), where the optimal secondary-access rule A * H is:…”

“…Recently, the authors in [14] proposed a new approach which aims to design MAC protocol for enabling Secondary Users (SU) to opportunistically access the idle time slots in a primary TDMA network. In this paper, two different traffic scenarios are considered when they design the MAC protocol.…”

Security-reliability trade-off for cognitive radio networks in the presence of eavesdropping attack

“…This provides us with an opportunity to develop a cognitive radio system that opportunistically utilizes the licensed spectrum. More specifically, if the licensed spectrum band is detected as idle, i.e., the band is not occupied by a licensed user (referred to as primary user), the cognitive radio system can reuse such idle licensed spectrum for data transmission [5]. In view of the above observations, cognitive radio relies on the spectrum sensing that is responsible for detecting and identifying the idle spectrum (known as spectrum hole).…”

Розробка Методу Вибору Каналів Когнітивного Радіо При Множинному Доступі Первинних Та Вторинних Користувачів З Використанням Технології «energy Harvesting» Під Керуванням Нейронної Мережі

“…На сьогоднішній день не існує ефективного ви-рішення конкуренції каналів між декількома пер-винними та вторинними користувачами [10,20,21]. Ґрунтуючись на методі виявлення і концепції кон-куренції каналів, для вирішення поставлених задач буде отримано можливість покращення точності аналізу спектру і пропускної здатності вторинних користувачів.…”