Two emerging technologies towards 5G wireless networks, namely non-orthogonal multiple access (NOMA) and cognitive radio (CR), will provide more efficient utilization of wireless spectrum in the future. In this article, we investigate the integration of NOMA with CR into a holistic system, namely cognitive NOMA network, for more intelligent spectrum sharing. Design principles of cognitive NOMA ...

Cognitive Radio (CR) is a new generation of wireless communication system that enables unlicensed users to exploit underutilized licensed spectrum to optimize the radio spectrum utilization. The resource allocation is difficult to achieve in a dynamic distributed environment, in which CR users take decisions to select a channel without negotiation, and react to the environmental changes. This p...

Cognitive Radio (CR) is a promising technique to address the spectrum scarcity issue by enabling the unlicensed network users (SUs) to dynamic access the spectrum holes. This thesis designs Medium Access Control (MAC) protocols for SUs to utilize the unused spectrum without interfering the licensed network users’ (PUs) transmissions; analyzes the MAC performance based on the queuing theories; a...

Cognitive Radio Sensor Networks (CRSNs) are composed of sensor nodes equipped with Cognitive Radio (CR) technology with limited resources (e.g., storage, computational speed, bandwidth, security, etc.). In order to overcome resource limitation, cognitive radio sensor nodes are integrated with cloud computing, which provides computing resources (e.g., storage, computation, security, etc.) to sen...

In this paper we consider cognitive processes and their impact on the performance of cognitive radio networks (CRN). We model the cognition cycle, the main control process of the cognitive radio (CR), during which CR sequentially senses and estimates the environment state, creates plans based on the knowledge (models) of itself and that of the environment, makes decisions in order to optimize c...

Cognitive radio (CR) is an enabling technology that helps efficiently use spectrum. In this paper, a collaborative spectrum sensing mechanism is proposed which combines passive detection and sensing service compensation. Theoretical analysis and simulations show that this method not only reduces the energy cost and the passive sensing time, but also maintains fairness in the CR communication sy...

In this paper we consider cognitive processes and their impact on the performance of cognitive radio networks (CRN). We model the cognition cycle, the main control process of the cognitive radio (CR), during which CR sequentially senses and estimates the environment state, creates plans based on the knowledge (models) of itself and that of the environment, makes decisions in order to optimize c...

Recently a spectral scarcity has arisen as a serious problem, because current static frequency allocation schemes cannot further accommodate an increasing number of devices requesting higher data rate. Therefore, CR (cognitive radio) technique has been considered as a potential solution to improve spectrum utilization by sharing the spectrum. In this chapter, the main concept of CR was introduced.

In this paper, we propose two subspace-projection-based precoding schemes, namely, full-projection (FP)and partial-projection (PP)-based precoding, for a cognitive radio multiple-input multiple-output (CR-MIMO) network to mitigate its interference to a primary time-division-duplexing (TDD) system. The proposed precoding schemes are capable of estimating interference channels between CR and prim...

1.1 Introduction Under utilization of radio spectrum in traditional wireless communications systems [30], along with the increasing spectrum demand from emerging wireless applications, is driving the development of new spectrum allocation policies for wireless communications. These new spectrum allocation policies, which will allow unlicensed users (i.e., secondary users) to access the radio sp...