4. Smart Antenna Array:
Antenna array with a digital signal processing
capability to transmit and receive in an adaptive and spatially
sensitive manner.
9. Beam-forming
Technique in which the gain
pattern of an adaptive array is
steered to a desired direction
through either beam steering or
null steering signal processing
algorithms
Adaptive beam forming algorithms
can provide substantial gains (of Antenna Pattern of 7-element
the order of 10log(M) dB, where M uniform equally spaced
is number of array elements) circular array.
10. Adaptive Beam-forming
An adaptive beam former is a
device that is able to separate
signals co-located in the
frequency band but separated in
the spatial domain. This provides
a means for separating the desired
signal from interfering signals.
A two element adaptive array for
interference suppression
11. Switched beam
Consists of a set of predefined beams.
Allows selection of signal from desired user.
Beams have narrow main lobe & small side lobes.
Signals received from side lobes can be significantly attenuated.
Uses a linear RF network called Fixed Beam-forming network that
combines M antenna elements to form up-to M directional beams.
13. Dynamically phased array :
Consists of either a number of fixed beams with one beam turned
on towards the desired signal or a single beam (formed by
phase adjustment only) that is steered toward the desired
signal.
14. Dynamically phased array :
A Direction of arrival algorithm(DoA) tracks the user’s
signal as he roams within the range of that beam that is
tracking him
Generalization of switched beam concept where received
power is maximized.
More efficient than Switched beam system
15. What is DoA?
The goal of direction-of-arrival (DoA) estimation is to use the
data received on the downlink at the base-station sensor array
to estimate the directions of the signals from the desired mobile
users as well as the directions of interference signals.
16. Types of
Dynamically phased array
Time domain beamformers:
Delays the incoming signal from each array element by a certain
amount of time & then adds them.
Frequency domain beamformers:
Different frequencies are separated. Applying different sum & delay
to each frequency it is possible to point out the main lobe.
26. GSM
(Global system for Mobile Communication)
Mainly used in the base station.
Full beam adaptation in uplink & downlink.
Bit rate of 1%
Carrier interference of -14 db.
27. CDMA
Features
Diversity Cellular Antennas with 800/1900 MHz
bands
High accuracy GPS receiver
Supports UART and/or USB interfaces
Benefits
Designed for easy internal integration
no need of SIM card
Provides integrators with a network pre-approved
communication device
Fleet Management and diagnostics
In-dash Internet access
General Automotive Aftermarket
28. Wireless Communication
Over come the limitations of omni-directional antenna.
Secterized antenna and coverage pattern.
29. Aerospace Application
Smart antenna adapts the electromagnetic condition.
Increase of antenna gain
Airborne satellite communication.
Reliable source of communication.
30. SDMA
Spatial Division Multiple Access
Uses an array of antennas to
provide control of space
Network planning (frequency) is
simpler
More network management
upgrade required
31. IS-136
TDMA with 3 users per channel
162 symbols/slot
14 symbol synchronization sequence
Two receive antennas at base
32. Smart antennas in generation 3 rd
systems: EDGE
High data rate ( 384 kbps) service based on GSM, for
both Europe and North America
BPSK at 270.833 kbps
26 symbol training sequence
3 58 26 58 3 8.25
576.92 s
33. Advantages of smart antenna
Both phased and adaptive arrays provide increased power by
providing higher gain for the desired signal.
In terms of interference suppression, phased arrays reduce the
probability of interference with the narrower beam, and adaptive
arrays adjust the beam pattern to suppress interference.
34. Conclusion
The use of smart antennas is not purely a radio transmission
issue.
It also influences network services such as handover and
connection setup.
A smart antenna is a digital wireless communications
antenna system that takes advantage of diversity effect at the
source (transmitter), the destination (receiver), or both.
35. Reference
G. K. Chan, “Effects of Sectorization the Spectrum
Efficiency of Cellular Radio systems,” Transaction on
Vehicular Technology, pp.217-225, vol.41, no.3, Aug 1992.
M. G. Jansen, R. Prasad, “Capacity, Throughput, and
Delay Analysis of a Cellular DS CDMA System with Imperfect
Power Control and Imperfect Sectorization,” Transaction on
Vehicular Technology, pp.67-75, vol.44, no.1, Feb 1995.
X. Yang, S. Ghaheriand N. R. Tafazolli, “Sectorization
Gain in CDMA Cellular Systems,” First Conference on 3G
Mobile Communication Technologies, pp.70-75, 2000.
