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Outage probability analysis of uplink NOMA over ultra-high-speed FSO-backhauled systems
, Article 2018 IEEE Globecom Workshops, GC Wkshps 2018, 9 December 2018 through 13 December 2018 ; 2019 ; 9781538649206 (ISBN) ; Azimi Abarghouyi, S. M ; Mahdavifar, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we consider a relay-assisted uplink non-orthogonal multiple access (NOMA) system where two radio frequency (RF) users are grouped for simultaneous transmission, over each resource block, to an intermediate relay which forwards the amplified version of the users' aggregated signals in the presence of multiuser interference to a relatively far destination. In order to cope with the users' ever-increasing desire for higher data rates, a high-throughput free-space optics (FSO) link is employed as the relay-destination backhaul link. Dynamic-order decoding is employed at the destination to determine the priority of the users based on their instantaneous channel state information...
Interference alignment for two-user two-hop interference X-channel with delayed and no CSIT
, Article International Congress on Ultra Modern Telecommunications and Control Systems and Workshops, 6 October 2014 through 8 October 2014 ; Volume 2015-January, Issue January , 2015 , Pages 473-479 ; 21570221 (ISSN) ; Mirmohseni, M ; Akhaee, M. A ; Sharif University of Technology
IEEE Computer Society
2015
Abstract
Capacity approximation of multi-hop unicast and multi-hop multicast channels is one of unsolved problems in information theory. Recently some researches investigate Degrees of Freedom (DoF) characterization and Interference Alignment schemes for these channels. However most of them assumed perfect instantaneous Channel State Information (CSI) at the relays and the transmitters. Due to practical limitations, like the delay and the rate limitation in the feedback links and the fading channels, it is difficult to provide perfect instantaneous CSI at the transmitters and even the relays. Achievable DoF by the IA schemes collapses greatly with imperfect CSI. It has been shown that the delayed CSI...
Blind interference alignment for three-user multi-hop SISO interference channel
, Article International Congress on Ultra Modern Telecommunications and Control Systems and Workshops, 6 October 2014 through 8 October 2014 ; Volume 2015-January, Issue January , 2015 , Pages 462-467 ; 21570221 (ISSN) ; Mirmohseni, M ; Akhaee, M. A ; Sharif University of Technology
IEEE Computer Society
2015
Abstract
Interference Alignment (IA) is a rather new technique to achieve higher Degrees-of-Freedom (DoF) compared to traditional orthogonal naive methods, like, Time Division Multiple Access (TDMA). In many IA schemes, Instantaneous Channel State Information at Transmitter (CSIT) is mandatory. However, this requirement becomes an obstacle to implement those methods in practice. In some practical scenarios, it is not possible to provide instantaneous or even delayed CSIT. Recently, Blind Interference Alignment (BIA) has been introduced as a solution to align interference without CSIT. In spit of major advances in single-hop Interference Channels (ICs), few researches focused on multi-hop ICs. In this...