An opportunistic cognitive radio communication through the exploitation of the small-scale fading mechanisms of the LTE mobile channel

Gerardo Agni Medina-Acosta,José Antonio Delgado-Penín,Katsuyuki Haneda

doi:10.1186/1687-1499-2013-87

Gerardo Agni Medina-Acosta, José Antonio Delgado-Penín + Show 1 more

Open Access

https://doi.org/10.1186/1687-1499-2013-87

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Abstract

In recent years, the cognitive radio technology has attracted the attention of all the players in the telecommunication field (i.e., researchers, industry, service providers, and regulatory agencies) as a way of facing the spectrum scarcity. In this regard, and after having reviewed the vast activity linked to this concept it is quite easy to realize that the spectrum sensing task turns out to be the keystone of this technology. However, nowadays it is still unclear which is (are) going to be the globally recommended technique(s) for carrying out this procedure. So, and aiming at finding an alternative to the technical impediments behind the spectrum sensing task, this research work proposes that the advanced knowledge that is already being collected at the modern primary networks be used in benefit of the cognitive radios. Here, the 3GPP LTE network has been adopted as the primary system providing the information that the cognitive radio transceiver will be using for co-transmitting opportunistically (i.e., at specific moments) through the licensed radio resources, being the secondary access based on a novel model which proposes to overlay the secondary transmission whenever extreme channel conditions be found in the radio link of a particular primary user.

Highlights

The cognitive radio technology arose as a promising new paradigm in spectrum management aiming at overcoming the weakness embedded in the manner conventional radio devices communicate with each other at present.In a broad sense, the idea behind this revolutionary technological proposal consists in making that the cognitive radio devices be able to transmit adaptively once a highly trustable sensing procedure in real time has guaranteed the existence of spectrum holes which can freely be utilized under a double premise that consists in not causing excessive interference to the others, along with the mandatory release of Because all the implications stated above, this new generation of radio devices are considered to have cognition capabilities, being the so-called spectrum sensing task probably the most important, complex, and challenging procedure
The idea behind this revolutionary technological proposal consists in making that the cognitive radio devices be able to transmit adaptively once a highly trustable sensing procedure in real time has guaranteed the existence of spectrum holes which can freely be utilized under a double premise that consists in not causing excessive interference to the others, along with the mandatory release of
The SC-FDMA system became in the study object of this proposal, being the delay spread of the signal, and the time variance of the LTE mobile channel the crucial points of analysis

Summary

Introduction

The cognitive radio technology arose as a promising new paradigm in spectrum management aiming at overcoming the weakness embedded in the manner conventional radio devices communicate with each other at present. Under a dynamic allocation of resources the system stops having errors with an EbNo greater than 15 dB, while in the other case this occurs after having an EbNo greater than 18 dB Having these curves as reference, the channel information of a particular PU (i.e., UE in LTE) was tracked aiming at inducing an opportunistic communication taking place on its extreme conditions when P = PSU. It can be noticed that carrying out a secondary transmission overlaid on the best subcarriers (i.e., channel peaks) does not distort the primary communication beyond the previously observed order of magnitude, and that when no errors are identified in the conventional transmission, the BER of the interfered one moves up to having approximately one error per every 1,000,000 of bits received (i.e., ≈1 × 10–6). We can see through the SIR curve that the secondary communication moved dynamically along the granted bandwidth always pursuing the UE in question (i.e., avoiding to interfere with the others)

Conclusions

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