hybrid optical modi
TRANSCRIPT
-
7/31/2019 Hybrid Optical MODI
1/16
Prsented
By
REVATHIBANU
-
7/31/2019 Hybrid Optical MODI
2/16
Introduction
Project objectives and motivations
Communication System
Structured Redundancy
Forward Error Correction Turbo decoding
Abstract
Existing System
Existing System Disadvantage
Proposed System Proposed System Advantages
Block Diagram And explanation
Application
Conclusion
-
7/31/2019 Hybrid Optical MODI
3/16
TURBO codes have received considerable attention in providing
reliable communication links.
They find applications in 3rd Generation, digital video broadcasting
return channel via satellite (DVB-RCS), IEEE 802.16 and other
communication standards Simulations of turbo codes to evaluate their error performance in the
high signal-to-noise ratio (SNR) region is highly time consuming.
The performance of turbo codes over fully interleaved and
exponentially correlated Rayleigh fading channels has been
investigated in
-
7/31/2019 Hybrid Optical MODI
4/16
Motivation
Can we have error free communication as much as possible.
Objectives
Studying channel coding
Understanding channel capacity
Ways to increase data rate
Provide reliable communication link
-
7/31/2019 Hybrid Optical MODI
5/16
Structural modular approach
Various components
Of defined functions
Channel
Coding
Source
Coding
ModulationFormatting
Digitization
MultiplexingAccess
techniques
send
receive
-
7/31/2019 Hybrid Optical MODI
6/16
Channelencoder
Input word
k-bit
Output word
n-bit
Redundancy = (n-k)
Code rate = k/n
codewordCode sequence
-
7/31/2019 Hybrid Optical MODI
7/16
Turbo coded data transmission over a hybrid channel, consisting
of parallel free space optical (FSO) and radio frequency (RF)
links, is considered, and analytical bit error performance results
are derived.
In this paper, we are going to develop BER analysis of turbocodes for hybrid FSO/RF channels using the transfer function
bounding technique.
Random and specific codeword bit selection for Transmission
through the RF link are considered.
Joint optimization of puncturing and RF bit selection patterns
also one of the major conept in this application
-
7/31/2019 Hybrid Optical MODI
8/16
First, BER analysis for a turbo coded system that transmitsrandomly selected codeword bits through the RF link is derived
Second, we present a procedure to analyze BER performance inhybrid channels when specific codeword bits are selected for
transmission through the RF link Finally, we present a novel technique to jointly optimize
puncturing and RF bit selection patterns.
-
7/31/2019 Hybrid Optical MODI
9/16
Considering the word length in mind we go for this hybrid technique
which be implemented either FSO or RF channels.
FSO links have large unlicensed bandwidths but they are more
affected by various atmospheric factors, including scattering,
absorption, and atmospheric turbulence. Due to limited RF bandwidths, most of the data are transmitted
through the dominant FSO link, leaving out only a small fraction to
be carried by the RF link.
-
7/31/2019 Hybrid Optical MODI
10/16
Disadvantages
- Photonic NW is a complex system ( a large number of
different functions must cooperate for a network such as
transmission
Routing and Switching
Control and management
Intractable problem (NP-Complete).
Therefore, assumptions and heuristics are used to reduce the
process complexity.
-
7/31/2019 Hybrid Optical MODI
11/16
Parallel FSO/RF hybrid channels have been analyzed in using low
density parity check (LDPC) codes.
In performance of convolution codes has been studied for hybrid
channels, and code design and power assignment criteria are
investigated. Our proposed approach utilizes a weight-two input sequence
algorithm to reduce the search space.
The proposed method can also be used for designing codes in other
hybrid channels
-
7/31/2019 Hybrid Optical MODI
12/16
Advantages
Solve the electronic equipment bottleneck
Exploit the existing network Support services such as connection on demand
Improves bandwidth (BW) efficiency and source utilization of the network.
-
7/31/2019 Hybrid Optical MODI
13/16
INTER
LEAVER
PUNT
URINGENCODER 1ENCODE 2
RF LINK
OPTICAL
LINK
SNR
VALUE
SNR
VALUE
COMPA
RISION
-
7/31/2019 Hybrid Optical MODI
14/16
In Section II, we present the hybrid channel model. In Section III, a BER analysis for the hybrid channel when
randomly selected codeword bits are transmitted throughthe RF link is presented
. Section IV describes BER analysis when specific codewordbits are transmitted through the RF link.
Section V presents our idea of joint optimization ofpuncturing and RF bit selection patterns
In Section VI, numerical results showing significant
benefits from the turbo coded transmission through thehybrid channel are presented.
Section VII concludes our study.
-
7/31/2019 Hybrid Optical MODI
15/16
are used extensively in 3G and 4G mobile telephony standards MILITARY AND LAW ENFORCEMENT
Can be used to improve the interface in systems that employ multiple trellis-based algorithms.
Applications include Telephones
Internet LANs - local area networks CATV - for video, voice and Internet connections Utilities - management of power grid
Security - closed-circuit TV and intrusion sensors Military - everywhere!
Multimedia systems require varying quality of service. QoS Latency
Low latency for voice, teleconferencing
Bit/frame error rate (BER, FER) Low BER for data transmission.
Mobile 3G systems In use in Japan UMTS NTT DoCoMo
Turbo codes : pictures/video/mail Convolutional codes : voice
http://en.wikipedia.org/wiki/3Ghttp://en.wikipedia.org/wiki/4Ghttp://en.wikipedia.org/wiki/4Ghttp://en.wikipedia.org/wiki/3G -
7/31/2019 Hybrid Optical MODI
16/16
Mature, stable, well established and implemented
In this paper, we develop BER analysis of turbo codes for
hybrid FSO/RF channels using the transfer functionbounding technique.
Random and specific codeword bit selection for
transmission through the RF link are considered.
The exact trade-offs that can be obtained between the
optical and RF link SNR values for maintaining a certainerror probability are described.
Joint optimization of puncturing and RF bit selectionpatterns is proposed