Space-Time Equalizers for MIMO High Speed WCDMA Downlinks

2007 ◽  
Vol 6 (7) ◽  
pp. 2582-2592 ◽  
Author(s):  
Markku Juntti ◽  
Kari Hooli ◽  
Kai Kiiskila ◽  
Jari Ylioinas
Keyword(s):  
High Speed ◽  
Space Time

Time, Topology, and the Twin Paradox

2011 ◽  
Author(s):  
Jean‐Pierre Luminet
Keyword(s):  
High Speed ◽  
Reference Frames ◽  
Thought Experiment ◽  
Flat Space ◽  
Space Time ◽  
Twin Paradox ◽  
Theory Of Relativity ◽  
Apparent Paradox ◽  
Curved Space ◽  
Gravitational Fields

This chapter notes that the twin paradox is the best-known thought experiment associated with Einstein's theory of relativity. An astronaut who makes a journey into space in a high-speed rocket will return home to find he has aged less than his twin who stayed on Earth. This result appears puzzling, as the homebody twin can be considered to have done the travelling with respect to the traveller. Hence, it is called a “paradox”. In fact, there is no contradiction, and the apparent paradox has a simple resolution in special relativity with infinite flat space. In general relativity (dealing with gravitational fields and curved space-time), or in a compact space such as the hypersphere or a multiply connected finite space, the paradox is more complicated, but its resolution provides new insights about the structure of space–time and the limitations of the equivalence between inertial reference frames.

scholarly journals DISCRETE-TIME MODELLING OP DISPERSION IN ESTURARIES

1980 ◽  
Vol 1 (17) ◽  
pp. 182
Author(s):  
T. Wood
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
High Speed ◽  
Transport Theory ◽  
State Parameter ◽  
Space Time ◽  
Tidal River ◽  
Primary Concern ◽  
Transport Parameters ◽  
Partial Differential

This paper aims to put forward a case in favour of a simple discretetime model describing mixing in an estuary. The model derives from the remarkably simple concepts developed by Ketchum (1951 a,b) which describe mixing in terms of tidal prism exchanges between segments. The author's view is that Ketchum1s ideas were abandoned before they were fully explored. A major factor was the advent of the high-speed computer which opened up the possibility of using an approach based on the space-time formulation of the problem in terms of the partial differential equations of transport theory. Intrinsically this approach, based on a continuum description, is more attractive than a gross description based on relatively large segments: one obvious reason is the possibility of providing a comprehensive space-time prediction of the spread of a pollutant. In practice, though, significant problems arise in its use: in particular, the following can be mentioned - a) substantial computing costs relating to computer program development and machine time b) specification of transport parameters inherent in the partial differential equations of transport: for example, dispersion coefficients c) model validation and state/parameter estimation. The last of these is the primary concern of this paper. It is probably true to say that, to date, too little attention has been given to these topics, in the context of estuarine modelling. The point to be made is that there is small justification in using a sophisticated description of a system if the resulting predictions of the model cannot be effectively validated. The ideas used in this paper stem from those put forward by Beck and Young (1975) in studies on non-tidal river pollution. The subsequent discussion suggests an extension to estuarine systems-.

Simulation of High-Speed Cavity Flows in a Scramjet Engine by the Space-Time CESE Method

2005 ◽  
Author(s):  
Shaeng-Tao J. Yu ◽  
Chang-Kee Kim ◽  
Zeng-Chan Zhang
Keyword(s):  
High Speed ◽  
Space Time ◽  
Cavity Flows ◽  
Scramjet Engine

Differential space-time block coding method for application in mobile radio communication systems using MIMO technology.

2021 ◽  
Author(s):  
M.S. Tokar ◽  
◽  
I.V. Ryabov ◽  
Keyword(s):  
Communication Systems ◽  
High Speed ◽  
Communication Channel ◽  
Space Time ◽  
The State ◽  
Radio Communication ◽  
Transmission Method ◽  
Space Time Coding ◽  
Channel One ◽  
Differential Transmission

In radio communication systems, when implementing coherent types of reception, it is assumed that the receiver knows information about the state of the communication channel, which is achieved by introducing signal redundancy (pilot signals). The frequency of sending pilot signals depends on factors that change the state of the communication channel, one of which is the high speed of movement of mobile stations. The use of pilot signals not only hinders the efficient use of the radio frequency resource, but also, in the case of fast fading, does not allow the channel to be estimated and tracked with the required accuracy. These disadvantages can be eliminated by using the differential transmission method, for the implementation of which there is no need to know information about the state of the channel. The application of the principles of differential transmission to space-time coding does not find sufficiently effective solutions that combine low computational complexity and energy efficiency of differential coding methods.

Space-Time-Coded High-Speed Reconfigurable Card-to-Card Free-Space Optical Interconnects

2017 ◽  
Vol 9 (2) ◽  
pp. A189 ◽  
Author(s):  
Ke Wang ◽  
Ampalavanapillai Nirmalathas ◽  
Christina Lim ◽  
Kamal Alameh ◽  
Efstratios Skafidas
Keyword(s):  
Free Space ◽  
Optical Interconnects ◽  
High Speed ◽  
Space Time ◽  
Free Space Optical
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