Computational complexity of optimal determination of cell sites and base station locations

2003 ◽  
Author(s):  
R. Bose
Keyword(s):  
Computational Complexity ◽  
Base Station

scholarly journals A Novel Iterative Discrete Estimation Algorithm for Low-Complexity Signal Detection in Uplink Massive MIMO Systems

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 980 ◽  
Author(s):  
Hui Feng ◽  
Xiaoqing Zhao ◽  
Zhengquan Li ◽  
Song Xing
Keyword(s):  
Computational Complexity ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Estimation Algorithm ◽  
Low Complexity ◽  
Detection Algorithm ◽  
Base Station ◽  
Damping Factor ◽  
Mimo Detection ◽  
Discrete Estimation

In this paper, a novel iterative discrete estimation (IDE) algorithm, which is called the modified IDE (MIDE), is proposed to reduce the computational complexity in MIMO detection in uplink massive MIMO systems. MIDE is a revision of the alternating direction method of multipliers (ADMM)-based algorithm, in which a self-updating method is designed with the damping factor estimated and updated at each iteration based on the Euclidean distance between the iterative solutions of the IDE-based algorithm in order to accelerate the algorithm’s convergence. Compared to the existing ADMM-based detection algorithm, the overall computational complexity of the proposed MIDE algorithm is reduced from O N t 3 + O N r N t 2 to O N t 2 + O N r N t in terms of the number of complex-valued multiplications, where Ntand Nr are the number of users and the number of receiving antennas at the base station (BS), respectively. Simulation results show that the proposed MIDE algorithm performs better in terms of the bit error rate (BER) than some recently-proposed approximation algorithms in MIMO detection of uplink massive MIMO systems.

scholarly journals Green’s Classifications and Evolutions of Fixed-Order Networks

Mathematics ◽  
2018 ◽  
Vol 6 (10) ◽  
pp. 174
Author(s):  
Allen D. Parks
Keyword(s):  
Computational Complexity ◽  
Equivalence Class ◽  
Network Evolution ◽  
Binary Relations ◽  
Internal Dynamics ◽  
Initial Network ◽  
Fixed Order ◽  
Symmetry Problem ◽  
Structural Invariants

It is shown that the set of all networks of fixed order n form a semigroup that is isomorphic to the semigroup BX of binary relations on a set X of cardinality n. Consequently, BX provides for Green’s L,R,H, and D equivalence classifications of all networks of fixed order n. These classifications reveal that a fixed-order network which evolves within a Green’s equivalence class maintains certain structural invariants during its evolution. The “Green’s symmetry problem” is introduced and is defined as the determination of all symmetries (i.e., transformations) that produce an evolution between an initial and final network within an L or an R class such that each symmetry preserves the required structural invariants. Such symmetries are shown to be solutions to special Boolean equations specific to each class. The satisfiability and computational complexity of the “Green’s symmetry problem” are discussed and it is demonstrated that such symmetries encode information about which node neighborhoods in the initial network can be joined to form node neighborhoods in the final network such that the structural invariants required by the evolution are preserved, i.e., the internal dynamics of the evolution. The notion of “propensity” is also introduced. It is a measure of the tendency of node neighborhoods to join to form new neighborhoods during a network evolution and is used to define “energy”, which quantifies the complexity of the internal dynamics of a network evolution.

scholarly journals Canadian Meteor Orbit Radar (CMOR)

2004 ◽  
Vol 4 (3) ◽  
pp. 679-684 ◽  
Author(s):  
A. R. Webster ◽  
P. G. Brown ◽  
J. Jones ◽  
K. J. Ellis ◽  
M. Campbell-Brown
Keyword(s):  
Angular Resolution ◽  
Base Station ◽  
Radar System

Abstract. The radar system described here (CMOR) comprises a basic 5-element receiving system, co-located with a pulsed transmitter, specifically designed to observe meteor echoes and to determine their position in space with an angular resolution of ~1° and a radial resolution of ~3 km. Two secondary receiving sites, a few km distant and arranged to form approximately a right angle with the base station, allow the determination of the velocity (speed and direction) of the meteor that, together with the time of occurrence, lead to an estimate of the orbit of the original meteoroid. Some equipment details are presented along with a method used to determine the orbits. Representative echoes are shown and observations on the 2002 Leonid shower presented.

scholarly journals Enhanced Transmit-Antenna Selection Schemes for Multiuser Massive MIMO Systems

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Byung-Jin Lee ◽  
Sang-Lim Ju ◽  
Nam-il Kim ◽  
Kyung-Seok Kim
Keyword(s):  
Computational Complexity ◽  
Radio Frequency ◽  
Spectral Efficiency ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Antenna Selection ◽  
Base Station ◽  
Base Stations ◽  
Transmit Antenna Selection ◽  
Selection Scheme

Massive multiple-input multiple-output (MIMO) systems are a core technology designed to achieve the performance objectives defined for 5G wireless communications. They achieve high spectral efficiency, reliability, and diversity gain. However, the many radio frequency chains required in base stations equipped with a high number of transmit antennas imply high hardware costs and computational complexity. Therefore, in this paper, we investigate the use of a transmit-antenna selection scheme, with which the number of required radio frequency chains in the base station can be reduced. This paper proposes two efficient transmit-antenna selection (TAS) schemes designed to consider a trade-off between performance and computational complexity in massive MIMO systems. The spectral efficiency and computational complexity of the proposed schemes are analyzed and compared with existing TAS schemes, showing that the proposed algorithms increase the TAS performance and can be used in practical systems. Additionally, the obtained results enable a better understanding of how TAS affects massive MIMO systems.

scholarly journals GPS determination of the velocity and strain-rate fields on Schirmacher Glacier, central Dronning Maud Land, Antarctica

2007 ◽  
Vol 53 (183) ◽  
pp. 558-564 ◽  
Author(s):  
P.S. Sunil ◽  
C.D. Reddy ◽  
M. Ponraj ◽  
Ajay Dhar ◽  
D. Jayapaul
Keyword(s):  
Strain Rate ◽  
Austral Summer ◽  
Base Station ◽  
Spatially Correlated ◽  
The North ◽  
Schirmacher Oasis ◽  
Global Positioning ◽  
Dronning Maud Land ◽  
Insight Into

Global positioning system (GPS) campaigns were conducted during the 2003 and 2004 austral summer seasons to obtain insight into the velocity and strain-rate distribution on Schirmacher Glacier, central Dronning Maud Land, East Antarctica. GPS data were collected at 21 sites and analyzed to estimate the site coordinates, baselines and velocities. The short-term precision of the base station, MAIT, is estimated from the daily coordinate repeatability solutions during the two years. All GPS points on the glacier were constrained with respect to MAIT and nearby International GPS Service stations. Horizontal velocities of the glacier sites lie between 1.89 ± 0.01 and 10.88 ± 0.01 ma−1 to the north-northeast, with an average velocity of 6.21 ± 0.01 m a−1. The principal strain rates provide a quantitative measurement of extension rates, which range from (0.11 ± 0.01) × 10−3 to (1.48 ± 0.85) × 10−3a−1, and shortening rates, which range from (0.04 ± 0.02) × 10−3 to (0.96 ± 0.16) × 10−3a−1. The velocity and strain-rate distributions across the GPS network in Schirmacher Glacier are spatially correlated with topography, subsurface undulations, fracture zones/crevasses and the partial blockage of the flow by nunataks and the Schirmacher Oasis.

scholarly journals NOMA and OMA-Based Massive MIMO and Clustering Algorithms for Beyond 5G IoT Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Taj Rahman ◽  
Feroz Khan ◽  
Inayat Khan ◽  
Niamat Ullah ◽  
Maha M. Althobaiti ◽  
...  
Keyword(s):  
Computational Complexity ◽  
Interference Cancellation ◽  
Massive Mimo ◽  
Multiple Access ◽  
Clustering Algorithms ◽  
Mobile Network ◽  
Base Station ◽  
Signal Interference ◽  
Global Changes ◽  
Power Requirement

The Internet of Things (IoT) has brought about various global changes, as all devices will be connected. This article examines the latest 5G solutions for enabling a massive cellular network. It further explored the gaps in previously published articles, demonstrating that to deal with the new challenges. The mobile network must use massive multiple input and output (MIMO), nonorthogonal multiple access (NOMA), orthogonal multiple access (OMA), signal interference cancellation (SIC), channel state information (CSI), and clustering. Furthermore, this article has two objectives such as (1) to introduce the cluster base NOMA to reduce the computational complexity by applying SIC on a cluster, which ultimately results in faster communication and (2) to achieve massive connectivity by proposing massive MIMO with NOMA and OMA. The proposed NOMA clustering technique working principle pairs the close user with the far user; thus, it will reduce computational complexity, which was one such big dilemma in the existing articles. This will specifically help those users that are far away from the base station by maintaining the connectivity. Despite NOMA’s extraordinary benefits, one cannot deny the significance of the OMA; hence, the other objective of the proposed work is to introduce OMA with MIMO in small areas where the user is low in number, it is already in use, and quite cheap. The next important aspect of the proposed work is SIC, which helps remove interference and leads to enhancement in network performance. The simulation result has clearly stated that NOMA has gained a higher rate than OMA: current NOMA users’ power requirement (weak signal user 0.06, strong signal user 0.07), spectral efficiency ratio for P-NOMA and C-NOMA (21%, 5%), signal-to-noise ratio OMA, P-NOMA, C-NOMA (28, 40, 55%), and user rate pairs NOMA, OMA (7, 3), C-NOMA, and massive MIMO NOMA SINR (4.0, 2.5).

scholarly journals An Enhanced Decoding Algorithm for Coded Compressed Sensing with Applications to Unsourced Random Access

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Vamsi K. Amalladinne ◽  
Jamison R. Ebert ◽  
Jean-Francois Chamberland ◽  
Krishna R. Narayanan
Keyword(s):  
Computational Complexity ◽  
Random Access ◽  
Base Station ◽  
Decoding Algorithm ◽  
Error Performance ◽  
Distributed Sensor Networks ◽  
Concatenated Coding ◽  
Distributed Sensor ◽  
Wide Range ◽  
Transmission Period

Unsourced random access (URA) has emerged as a pragmatic framework for next-generation distributed sensor networks. Within URA, concatenated coding structures are often employed to ensure that the central base station can accurately recover the set of sent codewords during a given transmission period. Many URA algorithms employ independent inner and outer decoders, which can help reduce computational complexity at the expense of a decay in performance. In this article, an enhanced decoding algorithm is presented for a concatenated coding structure consisting of a wide range of inner codes and an outer tree-based code. It is shown that this algorithmic enhancement has the potential to simultaneously improve error performance and decrease the computational complexity of the decoder. This enhanced decoding algorithm is applied to two existing URA algorithms, and the performance benefits of the algorithm are characterized. Findings are supported by numerical simulations.

Quantitative analysis of split base station processing and determination of advantageous architectures for LTE

2013 ◽  
Vol 18 (1) ◽  
pp. 105-128 ◽  
Author(s):  
Uwe Dotsch ◽  
Mark Doll ◽  
Hans-Peter Mayer ◽  
Frank Schaich ◽  
Jonathan Segel ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Base Station
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