This document provides an overview of adaptive modulation and coding (AMC) techniques. It defines AMC as adapting transmission parameters like modulation and coding based on constantly monitoring channel conditions. The goals of AMC are to improve efficiency, maximize throughput under different conditions, and guarantee high data transfer rates even during poor channel quality. It provides block diagrams of AMC systems and discusses current implementations in technologies like EGPRS and GPRS. The document also covers advantages like overcoming interference and fading, challenges like sensitivity to errors, and concludes that AMC improves throughput and range for wireless technologies.

1. Overview of Adaptive Modulation & CodingTechnique
(AMC)
Presented By
NAME: SUMAN BHATTACHARYYA
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2. Table of Content
 Introduction
 Adaptive modulation & Coding
 Block Diagram
 Importance of AMC
 Constraints
 Goal
 Current system using AMC
 Advantages of AMC
 Challenges of AMC
 Conclusion
 References
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3. Introduction
 Adaptive modulation and coding enables robust
and spectrally efficient transmission over time-
varying channels.
 AMC was introduced in the late sixties and early
seventies.
 The basic idea behind it is to adopting
transmission parameters according to channel
conditions by monitoring and measuring them.
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4. Adaptive modulation and coding (AMC)
 The modulation process formats the signal to best
transmit bits
◦ To overcome noise.
◦ To transmit as many bits as possible.
 Coding detects and corrects errors.
 AMC adapts to channel conditions
◦ Measures channel conditions.
◦ Sends messages between transmitter and
receiver to coordinate changes.
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5. Adaptive modulation and coding block
diagram
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6. Why Adaptive Modulation And Coding Is
Important ?
 Without AMC, there is inefficient utilization of
channel and wastage of power.
 With AMC, data rate and signal power are varied
as per the channel conditions for efficient
utilization of resources.
 AMC guarantees 99% of data transfer even at
worst channel conditions without any wastage of
resources.
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7. Constraints
 Adaptive modulation requires a feedback path
between the transmitter and the receiver, which
may not be feasible for some systems.
 If the channel changes faster than it can be
estimated and fed back to the transmitter,
adaptive modulation will perform very poorly.
 How often the transmitter can change its rate and
power.
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8. Goal Of Adaptive modulation and coding
 Adaptive Modulation & Coding is used to
improve the operational efficiency of Microwave
links by increasing network capacity over the
existing infrastructure.
 Adaptive Modulation means dynamically varying
the modulation in an errorless manner in order to
maximize the throughput under momentary
propagation conditions.
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9. CURRENT SYSTEMS USING AMC
 EGPRS for data transmission in GSM cellular
system uses 8PSK with 5 different code rates and
GMSK with 4 different code rates. Total 9
different coding and modulation schemes.
 GPRS for data transmission in IS-136 TDMA
cellular systems can use 4, 8, and 16 level PSK
modulation.
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10. Advantages Of Adaptive Modulation And
Coding
 Adaptive Modulation & Coding allows a wireless
system to choose the highest order modulation
depending on the channel conditions.
 Adaptive Modulation & Coding allows the system
to overcome fading and other interference.
 Maximize the throughput.
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11. Challenges
 AMC is sensitive to measurement error and delay.
In order to select the appropriate modulation, the
scheduler must be aware of the channel quality.
 Errors in the channel estimate will cause the
control to select the wrong data rate and either
transmit at too high a power, wasting system
capacity, or too low a power, raising the block
error rate.
 Complexity is very High.
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12. Conclusion
 Adaptive modulation is one method to improve
the throughput and/or range.
 The use of adaptive modulation allows wireless
technologies to optimize throughput, yielding
higher throughputs while also covering long
distances.
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13. References
 Wireless Communications by Andrea Goldsmith
(Edition 2005)
 https://iopscience.iop.org/article/10.1088/1757-
899X/78/1/012016#:~:text=Adaptive%20Modulation%2
0and%20Coding%20(AMC,MIMO%20antenna%20con
figuration%20is%20studied.
 https://www.academia.edu/36992931/Implementation_w
ith_Adaptive_Modulation_Technique_and_OFDM_Base
d_Approach
 https://uweb.engr.arizona.edu/~ivan/JOCN_AMC_FSO_
MAy10.pdf
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14. Thank You….
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