high-level wireless digital communications for program and engineering managers course sampler
DESCRIPTION
This two-day course is designed to provide an overall view of wireless communications including commercial and military applications for Program Managers, Engineering Managers, and others that do not have a technical engineering background and who are looking to understand Wireless Communications at a high level to be more effecting in dealing with customers, staff, and those working on these programs. It is also an excellent refresher course for those engineers that want to be more involved with Digital Communications in their careers. This is a very informative class at a high level so managers that are involved or going to be involved with Wireless Communications can understand at a high level what the engineers and programs are developing. It includes high level descriptions, enough detail to understand the concepts with little math or analysis involved. This is focus towards spread spectrum systems, which is nearly all of communications today. It covers a wide range of data link communication techniques, including tradeoffs of cost reduction and size reduction methods using a budget to determine what is needed for the wireless system. Thus the student gains a firm understanding of the processes needed to effectively understand wireless data link communication systems which is vital to their jobs. You will gain an intuitive understanding from all of the experiences of the Instructor who has been working with communications for over 25 years.This seminar has been taught to a number of Program Managers and other Managers at other companies with excellent feedback by those who took the class.Students will receive a copy of the instructor's textbook, Transceiver and Systems Design for Digital Communications, 3rd Edition.TRANSCRIPT
www.ATIcourses.com
Boost Your Skills with On-Site Courses Tailored to Your Needs The Applied Technology Institute specializes in training programs for technical professionals. Our courses keep you current in the state-of-the-art technology that is essential to keep your company on the cutting edge in today’s highly competitive marketplace. Since 1984, ATI has earned the trust of training departments nationwide, and has presented on-site training at the major Navy, Air Force and NASA centers, and for a large number of contractors. Our training increases effectiveness and productivity. Learn from the proven best. For a Free On-Site Quote Visit Us At: http://www.ATIcourses.com/free_onsite_quote.asp For Our Current Public Course Schedule Go To: http://www.ATIcourses.com/schedule.htm
Bullock Engineering Research Copyright 2010
1
Link Budget
• Link - Connects the Transmitter to the Receiver
• Budget - Allocation of Power and Noise through the Link
• Tracks Signal & Noise Levels from Tx PA to Rx Detector (LNA)
– Power Output (PA), Tx Losses, Channel Losses, Rx Losses
– Signal/Noise at Receiver’s Detector
– Required S/N (or Eb/No for BER)
• Used in Solving Tradeoffs
– Size, cost, data rate, LPI/LPD, waveform, coding, etc.
Power & Noise Through the Link
Tx Antenna
Transmitter
Rx Antenna
Receiver
Bullock Engineering Research Copyright 2010
2
Digital vs. Analog Comms
A/D
5V analog = Digital 101
5V
Mod Demod
Digital 101 = 5V analog
5V
D/A
LO LO
Sampler
Analog + Noise
Digital
Mod Demod
LO LO
Analog System
Digital System
Perfect Reconstruction of the Digital Waveform Assuming No Bit Errors
Analog
PSK, FH, etc.
AM/FM etc
Bullock Engineering Research Copyright 2010
3
Digital Modulation Creates
Frequency Waveform (Sinc)
2/PW
Null to Null Bandwidth
2 x Bit/Chip Rate
f
PdBm
V
t
Time Domain
Frequency Domain
Direct Sequence Digital Modulation
Shifts the phase of the carrier frequency according to the data
Bullock Engineering Research Copyright 2010
4
Spread Spectrum for Direct
Sequence and Frequency Hop – Spread Spectrum uses more bandwidth than is required to send data
Faster pseudo-random code spreads the bandwidth
Higher the code rate, wider the bandwidth
Signal
PdBm PdBm
f
Signal
Spread Spectrum
High Speed PN-code
Frequency hop spreads the bandwidth
More frequencies, wider the bandwidth
Spread Spectrum
Frequency Hop
Wideband
Spread Spectrum Wideband
Spread Spectrum
f Narrowband
Signal
Narrowband
Signal
Bullock Engineering Research Copyright 2010
5
Multiple User Techniques
Code 1
Code 2
Code 3
System 1
System 2
System 3
time 1 2 3 1 2 3
System 1 System 2 System 3
a. Time division multiple access
b. Code division multiple access.
.
Frequency
System 1 System 2 System 3
c. Frequency division multiple access.
f2 f3 f1
PdBm
V
Frequency Division Multiple Access (FDMA) Users operate on different frequencies
Time Division Multiple Access (TDMA) Users divided up in time slots.
Code Division Multiple Access (CDMA) Users have different codes
Bullock Engineering Research Copyright 2010
6
Power Control for
Near/Far Problems
Required in CDMA and other multiplexing schemes
Reduce the effects of Near/Far problems
Goal is to have equal power from users
Used where process gain is inadequate for good separation of users
Bullock Engineering Research Copyright 2010
7
Improvements To Eliminate
Errors in QPSK –Bit rate same
–Decrease BW
–Decrease Noise
–No Errors
–Increase Symbol S/N
–Provides twice the data rate
–Same BW
–No Errors
Bullock Engineering Research Copyright 2010
8
Antenna Diversity Example
Two or more antennas
Automatic selection of best signal
Theory:when one antenna is in a multipath null, the
other is not
Works very well with only two antennas
Antennas separated a short distance to prevent both
antennas from being in the null
Lab example with 2.4 GHz wireless modem
connection - Separation approximately 5”
Bullock Engineering Research Copyright 2010
9
Adaptive Filter with Two
Interfering Signals
Bullock Engineering Research Copyright 2010
10
Differential GPS
N
S
E W Surveyed Point
Offset from
Surveyed point
Differential Corrections
between surveyed point vs GPS
Uses corrections for
Accurate positioning
Bullock Engineering Research Copyright 2010
11
GPS Landing Systems
D8PSK LPI/Anti-jam Data Link
Sends GPS Corrections
Relative GPS for moving platforms (Aircraft Carriers)
Kinematic Carrier Phase Tracking KCPT for CATIII landing systems
Bullock Engineering Research Copyright 2010
12
Satellite Two-Way
Communications
Coherent Quadrature Phase Shift Keying (QPSK)
Bullock Engineering Research Copyright 2010
13
MIMO, MISO, SIMO
Monitor & Control
Transmitter
Transmitter
Transmitter
Receiver
Receiver
Receiver
MIMO
Increased Data Rate
or Robustness
MISO – Transmitter Antenna Diversity
Multipath, Noise, Jammer Mitigation
SIMO – Receiver Antenna Diversity
Multipath, Noise, Jammer Mitigation
Bullock Engineering Research Copyright 2010
14
Beam Positioning of
AESAs to Mitigate Multipath
AESA
Position
Difference
Reflection/Multipath
Amp
Distance
Null Position
Mitigates Multipath
