Cognitive Radio and the New Spectrum Paradigm for 5G

Abstract

In this chapter, we discuss the new spectrum paradigm for the 5th generation wireless systems (5G). It is expected that wireless data traffic will grow substantially in the next 5 years. By 2020, we expect to see 1000–10000-fold traffic increase. This increase comes from several trends, including the rapid increase of mobile devices, the increase of data traffic itself and the emergence of new applications and use cases such as the Internet of Things. Therefore, how to increase the system and link capacity becomes a key ingredient in 5G system design. Among the many solutions to meet this increased capacity demand, they can be broadly categorized into either one of two approaches. One is to increase spectrum efficiency through state of the art techniques such as massive MIMO, network cooperation or others. The other is to introduce new spectral resources and adoption of innovative approaches in the management and access to new and existing spectrum. In this chapter, the focus is on the latter i.e. the introduction and access management of new spectral resources to support the substantial traffic increase in 5G. This chapter starts with an introduction to the concept of dynamic spectrum access and the principles of radio resources sharing with Cognitive Radio. Sensing techniques and access policy are described. This section concludes with an overview of the various standardization efforts related to dynamic spectrum access for Cognitive Radio. In section “Spectrum and Channel Model”, spectrum allocation and availability for both the low and high frequencies are reviewed and the mmWave frequency bands are identified. The various challenges and ongoing studies to understand and model the channel at mmWave are explained and a Clustered Delay Line channel model produced by the Third Generation Partnership Program (3 GPP) is introduced. This section concludes with a brief introduction of the adoption of hybrid beam forming to address the challenges of high path loss with mmWave wireless communications. Finally in the last section, the concept of spectrum sharing with License Shared Access (LSA) and its 2 and 3-tie LSA architectures is explained.