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Resource allocation using fragmented-spectrum synchronous OFDM-CDMA in cognitive radio networks
, Article IWCIT 2014 - Iran Workshop on Communication and Information Theory ; May , 2014 ; ISBN: 9781479948772 ; Poursaeed, O ; Salehi, J. A ; Sharif University of Technology
Abstract
This paper presents a fragmented-spectrum synchronous OFDM-CDMA modulation and utilize it as secondary users modulation in a cognitive radio-based network to provide high data rate by efficiently exploiting available spectrum bands in a target spectral range while simultaneously offering multiple-access capability. In particular, given preexisting communications in the spectrum where the system is operating, a channel sensing and estimation method is used to obtain information of subcarrier availability. Given this information, some three-level codes are provided for emerging new cognitive radio users. Furthermore, analytical results of the system performance in a typical cognitive radio...
Analytical studies of fragmented-spectrum multi-level OFDM-CDMA technique in cognitive radio networks
, Article 7th IEEE Annual Ubiquitous Computing, Electronics and Mobile Communication Conference, UEMCON 2016, 20 October 2016 through 22 October 2016 ; 2016 ; 9781509014965 (ISBN) ; Sharifi Malvajerdi, S ; Poursaeed, O ; Salehi, J. A
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
In this paper, we present a multi-user resource allocation framework using fragmented-spectrum synchronous OFDM-CDMA modulation over a frequency-selective fading channel. In particular, given pre-existing communications in the spectrum where the system is operating, a channel sensing and estimation method is used to obtain information of subcarrier availability. Given this information, some real-valued multi-level orthogonal codes, which are orthogonal codes with values of {±1, ±2, ±3, ±4,...}, are provided for emerging new users, i.e., cognitive radio users. Additionally, we have obtained a closed form expression for bit error rate of cognitive radio receivers in terms of detection...