Papers by Ata sattarzadeh
Performance improvement of the PU2RC transmission schemes
IET Communications, Mar 27, 2014
ABSTRACT
IEEE Access
Non-terrestrial networks (NTNs) will become an indispensable part of future wireless networks. In... more Non-terrestrial networks (NTNs) will become an indispensable part of future wireless networks. Integration with terrestrial networks will provide new opportunities for both satellite and terrestrial telecommunication industries and therefore there is a need to harmonize them in a unified technological framework. Among different NTNs, low earth orbit (LEO) satellites have gained increasing attention in recent years and several companies have filed federal communication commission (FCC) proposals to deploy their LEO constellation in space. This is mainly due to several desired features such as large capacity and low latency. In addition, recent successful LEO network deployments such as Starlink have motivated other companies. In the past satellite and terrestrial wireless networks have been evolving separately but now they are joining forces to enhance coverage and connectivity experience in the future wireless networks. The 3rd Generation Partnership Project (3GPP) is one of the dominating standardization bodies that is working on various technical aspects to provide ubiquitous access to the 5G networks with the aid of NTNs. Initial steps have been taken to adopt 5G state of the art technologies and concepts and harmonized them with the conditions met in non-terrestrial networks. In this article, we review some of the important technical considerations in 5G NTNs with emphasis on the radio access network (RAN) part and provide some simulation based results to assess the required modifications and shed light on the design considerations. INDEX TERMS New Radio (NR), Non-terrestrial Networks (NTNs), 5G.
Interwoven random unitary beamforming for MIMO broadcast channels
We consider a multiple-input multiple-output broadcast channel where the transmitter performs uni... more We consider a multiple-input multiple-output broadcast channel where the transmitter performs unitary beamforming using the channel state information obtained through limited feedback from the receivers. A new feedback structure is proposed which considerably boosts the performance of the system compared with the conventional beamforming techniques like zero forcing beamforming or per user unitary and rate control. Because of the structure of the proposed feedback design, the new scheme is named interwoven random unitary beamforming or IRUB. In IRUB, the multiple-input multiple-output channel is in fact continuously decomposed into M orthogonal channels where the signal transmissions over them have timing offsets. User scheduling and beamforming in IRUB is very simple. User selection in IRUB is accomplished only based on the SINR feedbacks, and in each scheduling phase, only the scheduled users are inquired to send their channel direction information to the transmitter. Thereby, the...
TOA Extraction in Multipath Fading Channels for Location Estimation
Bounds on the throughput performance of PU<sup>2</sup>RC
2011 IEEE 22nd International Symposium on Personal, Indoor and Mobile Radio Communications, 2011
We consider the multiple-input multiple-output broadcast channels and the per user unitary and ra... more We consider the multiple-input multiple-output broadcast channels and the per user unitary and rate control (PU2RC) transmission and we characterize the performance of this transmission scheme for arbitrary number of active users in the network. In this paper we first introduce the method of computing the probability distribution of the feedback SINR in the PU2RC and will show that unlike
A simple and efficient method of multipath rejection (MPR) in Multipath fading channels for location estimations
2006 IEEE GCC Conference (GCC), 2006
IEEE Access
Although Geostationary-Equatorial-Orbit (GEO) satellites have achieved significant success in con... more Although Geostationary-Equatorial-Orbit (GEO) satellites have achieved significant success in conducting space missions, they cannot meet the 5G latency requirements due to the far distance from the earth surface. Therefore, Low-Earth-Orbit (LEO) satellites arise as a potential solution for the latency problem. Nevertheless, integrating the 5G terrestrial networks with LEO satellites puts an increased burden on the satellites' limited budget, which stems from their miniature sizes, restricted weights, and the small available surface for solar harvesting in the presence of additional required equipment. This paper aims to design the Electrical Power System (EPS) for 5G LEO satellites and investigate altitudes that meet the latency and capacity requirements of 5G applications. In this regard, accurate solar irradiance determination for the nadir-orientation scenario, Multi-Junction (MJ) solar cells modeling, backup batteries type and number, and designing highly-efficient converters are addressed. Accordingly, the power budgeting of the 5G LEO satellite can be achieved based on defining the maximum generated power and determining the satellite's subsystem power requirements for 5G missions. In the sequel, the measured and simulated values of the electrical V-I characteristics of an MJ solar panel are compared to validate the model by using a Clyde Space solar panel that reaches a maximum power generation of approximately 1 W at (I MPP = 0.426 A, V MPP = 2.35 V). Moreover, a synchronous boost converter circuit is designed based on commercial off-theshelf elements. INDEX TERMS 5G, CubeSat, electrical power system (EPS), low-earth-orbit (LEO) satellites, multijunction (MJ) solar cells.
Uploads
Papers by Ata sattarzadeh