A closer view on the hierarchical modulation, going further with the penalty analysis performed in a research paper regarding that subject.
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This presentation contain each and every single information on the topic.
If you like it do follow and like my presentation.
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This document provides an overview of digital-to-analog modulation techniques used in data communications including: Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), and Quadrature Amplitude Modulation (QAM). It defines these techniques, discusses their advantages and limitations, and provides examples of calculating bit rates and bandwidth requirements. Key points covered include how digital data is modulated onto an analog carrier signal, the relationship between bit rate and baud rate, and how more advanced modulations like QAM combine aspects of ASK and PSK.
This document provides an overview of channel estimation strategies used in orthogonal frequency division multiplexing (OFDM) systems. It describes the basic types of channel estimation methods: block-type pilot channel estimation and comb-type pilot channel estimation. For block-type estimation, pilots are inserted into all subcarriers of OFDM symbols periodically. This allows estimation of the channel conditions between pilot symbols. Estimation can be done with least squares (LS), minimum mean-square error (MMSE), or modified MMSE. For comb-type estimation, pilots are inserted into certain subcarriers of each symbol, requiring interpolation to estimate data subcarriers. The document compares the implementation complexity and performance of different estimation methods.
This document discusses different techniques for achieving diversity in wireless communications and combining received signals:
1. Selection diversity techniques select the strongest signal from multiple antennas, either based on received signal strength (RSSI) or bit error rate (BER). Combining diversity techniques combine all received signals.
2. Combining diversity techniques include maximal ratio combining (MRC), which weights signals by amplitude, and equal gain combining (EGC), which weights all signals equally after phase correction. MRC achieves better performance than EGC when signals are highly faded.
3. The document compares the advantages and disadvantages of different selection criteria and combining techniques. It also describes switched and feedback selection diversity approaches.
Amplitude shift keying (ASK) is a digital modulation technique that represents binary data by changing the amplitude of a carrier wave. In binary ASK (BASK), also known as on-off keying (OOK), a high amplitude represents a binary 1 and a low or off amplitude represents a binary 0. The demodulator determines the amplitude of the received signal to recover the original data. ASK transmitters and receivers have a simple design but the transmission is susceptible to noise. ASK is used in early telephone modems and transmitting digital data over optical fibers.
3.4_OOK systems – ASK, FSK, PSK, BPSK, QPSK, applications of Data communicati...BalaMurugan992669
1. The document discusses various digital modulation techniques including Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), Binary Phase Shift Keying (BPSK), and Quadrature Phase Shift Keying (QPSK).
2. It provides details on the principles, modulation, and demodulation of each technique. ASK modulates the amplitude of the carrier signal, FSK uses frequency modulation, while PSK and its variants BPSK and QPSK modulate the phase of the carrier signal.
3. The techniques find applications in data communication, wireless networks, and other systems due to advantages like higher data capacity and security compared to analog modulation.
This document provides an overview of decimation and interpolation in multirate signal processing. It discusses downsampling by an integer factor M, which reduces the sampling rate by taking every M-th sample and discarding the rest. Downsampling can cause aliasing if the signal is not bandlimited, so a low-pass filter is used beforehand. The document also covers properties like linearity and time-variance, identities for cascading systems, and polyphase decomposition to more efficiently implement decimation filters when the number of coefficients is a multiple of the decimation factor. Examples and illustrations are provided using MATLAB code.
The document discusses phase-shift keying (PSK) modulation techniques. It begins with an introduction to PSK and how it uses phases to encode digital data. It then discusses binary phase-shift keying (BPSK) which uses two phases separated by 180 degrees to encode one bit per symbol. BPSK is robust but has a low data rate. Quadrature phase-shift keying (QPSK) is then introduced, which uses four phases separated by 90 degrees to encode two bits per symbol, doubling the data rate of BPSK. Implementations of BPSK and QPSK modulators and demodulators are provided along with diagrams of their constellation plots.
This presentation contain each and every single information on the topic.
If you like it do follow and like my presentation.
It would be worth my efforts.
This document provides an overview of digital-to-analog modulation techniques used in data communications including: Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), and Quadrature Amplitude Modulation (QAM). It defines these techniques, discusses their advantages and limitations, and provides examples of calculating bit rates and bandwidth requirements. Key points covered include how digital data is modulated onto an analog carrier signal, the relationship between bit rate and baud rate, and how more advanced modulations like QAM combine aspects of ASK and PSK.
This document provides an overview of channel estimation strategies used in orthogonal frequency division multiplexing (OFDM) systems. It describes the basic types of channel estimation methods: block-type pilot channel estimation and comb-type pilot channel estimation. For block-type estimation, pilots are inserted into all subcarriers of OFDM symbols periodically. This allows estimation of the channel conditions between pilot symbols. Estimation can be done with least squares (LS), minimum mean-square error (MMSE), or modified MMSE. For comb-type estimation, pilots are inserted into certain subcarriers of each symbol, requiring interpolation to estimate data subcarriers. The document compares the implementation complexity and performance of different estimation methods.
This document discusses different techniques for achieving diversity in wireless communications and combining received signals:
1. Selection diversity techniques select the strongest signal from multiple antennas, either based on received signal strength (RSSI) or bit error rate (BER). Combining diversity techniques combine all received signals.
2. Combining diversity techniques include maximal ratio combining (MRC), which weights signals by amplitude, and equal gain combining (EGC), which weights all signals equally after phase correction. MRC achieves better performance than EGC when signals are highly faded.
3. The document compares the advantages and disadvantages of different selection criteria and combining techniques. It also describes switched and feedback selection diversity approaches.
Amplitude shift keying (ASK) is a digital modulation technique that represents binary data by changing the amplitude of a carrier wave. In binary ASK (BASK), also known as on-off keying (OOK), a high amplitude represents a binary 1 and a low or off amplitude represents a binary 0. The demodulator determines the amplitude of the received signal to recover the original data. ASK transmitters and receivers have a simple design but the transmission is susceptible to noise. ASK is used in early telephone modems and transmitting digital data over optical fibers.
3.4_OOK systems – ASK, FSK, PSK, BPSK, QPSK, applications of Data communicati...BalaMurugan992669
1. The document discusses various digital modulation techniques including Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), Binary Phase Shift Keying (BPSK), and Quadrature Phase Shift Keying (QPSK).
2. It provides details on the principles, modulation, and demodulation of each technique. ASK modulates the amplitude of the carrier signal, FSK uses frequency modulation, while PSK and its variants BPSK and QPSK modulate the phase of the carrier signal.
3. The techniques find applications in data communication, wireless networks, and other systems due to advantages like higher data capacity and security compared to analog modulation.
This document provides an overview of decimation and interpolation in multirate signal processing. It discusses downsampling by an integer factor M, which reduces the sampling rate by taking every M-th sample and discarding the rest. Downsampling can cause aliasing if the signal is not bandlimited, so a low-pass filter is used beforehand. The document also covers properties like linearity and time-variance, identities for cascading systems, and polyphase decomposition to more efficiently implement decimation filters when the number of coefficients is a multiple of the decimation factor. Examples and illustrations are provided using MATLAB code.
The document discusses phase-shift keying (PSK) modulation techniques. It begins with an introduction to PSK and how it uses phases to encode digital data. It then discusses binary phase-shift keying (BPSK) which uses two phases separated by 180 degrees to encode one bit per symbol. BPSK is robust but has a low data rate. Quadrature phase-shift keying (QPSK) is then introduced, which uses four phases separated by 90 degrees to encode two bits per symbol, doubling the data rate of BPSK. Implementations of BPSK and QPSK modulators and demodulators are provided along with diagrams of their constellation plots.
In digital modulation, minimum-shift keying(MSK) is a type of continuous-phase frequency-shift keying that was developed in the late 1950s and 1960s.
Similar to OQPSK(Offset quadrature phase-shift keying),
This document provides an overview of digital signal processors (DSPs). It defines a DSP as an integrated circuit designed for high-speed data manipulation used in applications such as audio, communications, and image processing. The document discusses how DSPs work by converting analog signals to digital signals and processing them. It explains that DSPs are needed because they can perform multiplication and division faster than general-purpose processors. The rest of the document details the architecture of DSPs, examples of DSP chip families like TMS320, and how instruction pipelining is implemented on the TMS320C54X DSP processor.
The most fundamental digital modulation techniques are based on keying: PSK (phase-shift keying): a finite number of phases are used. FSK (frequency-shift keying): a finite number of frequencies are used. ... QAM (quadrature amplitude modulation): a finite number of at least two phases and at least two amplitudes are used.
5. analog to digital conversion. ( pcm ,dm with short descriptions )MdFazleRabbi18
This document discusses two techniques for analog-to-digital conversion: pulse code modulation (PCM) and delta modulation. PCM samples an analog signal at regular intervals, quantizes the signal levels into discrete values, then encodes the samples into a digital bitstream using pulse amplitude modulation. Delta modulation encodes the differences between samples rather than their absolute values, sending a "1" if the value increases and a "0" if it decreases. Both techniques allow analog signals to be represented digitally but PCM works better for signals with small changes while delta modulation is better suited to signals with larger variations between samples.
The document summarizes various digital modulation and demodulation schemes used in wireless communication systems. It describes the structure of a basic wireless communication link and then provides details about modulation formats such as BPSK, DPSK, QPSK, OQPSK, and π/4 QPSK. It explains the key aspects of each scheme such as symbol mapping, transmitter and receiver operations, and their advantages over other schemes in terms of spectral efficiency and robustness to noise and fading channels.
Gaussian Minimum Shift Keying (GMSK) is a form of continuous-phase frequency shift keying that uses a Gaussian filter to generate a constant envelope signal. It provides better spectral efficiency than MSK through bandwidth reduction while maintaining low intersymbol interference. GMSK is used widely in wireless technologies like GSM and CDPD due to its power efficiency and good bit error rate performance compared to other modulation schemes. While more spectrally efficient than MSK, GMSK also has slightly higher error rates and requires more complex receivers.
Digital modulation techniques change aspects of a carrier signal to transmit information. This document discusses various digital modulation methods including:
- Amplitude modulation (AM) which varies the amplitude (A) of the carrier.
- Frequency modulation (FM) which varies the frequency (ω) of the carrier.
- Phase modulation (PM) which varies the phase (φ) of the carrier.
It then discusses specific modulation techniques including amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK) and their variants like quadrature phase shift keying (QPSK). The document provides illustrations of the modulated signals and discusses their bandwidth efficiency and performance in noise.
Amplitude Shift Keying (ASK) is a modulation technique where the amplitude of a carrier signal is varied according to the amplitude levels of a digital signal. In ASK, a digital signal of 1s and 0s is multiplied with a carrier signal, with a 1 having no effect on the carrier signal but a 0 reducing the carrier signal amplitude to zero. ASK has high efficiency and low noise interference but also high bandwidth and power consumption, making it suitable for applications like satellite links.
The document discusses various topics related to digital communication systems including:
- Advantages of digital over analog communication systems such as noise immunity and easier implementation of error control coding.
- The process of analog to digital conversion including sampling, quantization, encoding, and pulse code modulation (PCM).
- Digital modulation techniques like differential PCM (DPCM) and delta modulation (DM) that reduce redundancy before encoding.
- Considerations for line coding binary data onto an analog channel such as bandwidth, noise immunity, power efficiency and self-clocking capability.
Quadrature amplitude modulation (QAM) is a modulation technique that encodes data by changing both the amplitude and phase of carrier waves. It allows more data to be transmitted over a given bandwidth compared to techniques that only vary the amplitude or phase. QAM modulators use two carrier waves shifted in phase by 90 degrees that are modulated by separate data streams before being combined. Higher order QAM schemes use constellations with more points that allow more bits to be encoded per symbol. While this improves bandwidth efficiency, it also makes the system more susceptible to noise. QAM is widely used in technologies like DSL, wireless networks, cable TV, and microwave backhaul systems.
Bit error rate (BER) is a measure of the error probability in a digital transmission system. It is defined as the ratio of wrongly received bits to the total number of transmitted bits. A low BER is necessary for reliable digital communication. BER can be measured using a bit error rate tester which transmits a test pattern and counts the number of errors. BER is affected by noise and interference in the transmission channel. Noisy or burst errors are more difficult to correct than random errors. BER is an important parameter to characterize the quality and reliability of a communication system.
Phase-shift keying (PSK) is a digital modulation technique that conveys data by changing the phase of a carrier wave. There are several types of PSK including binary PSK (BPSK) and quadrature PSK (QPSK). BPSK uses two phases separated by 180 degrees to transmit 1 bit per symbol, while QPSK uses four phases separated by 90 degrees to transmit 2 bits per symbol for higher data rates. PSK has advantages like more efficient data transmission compared to frequency-shift keying. However, it is non-coherent and more prone to incorrect demodulations. PSK finds applications in optical communications, local oscillators, and delay-and-add demodulation.
A Brief Knowledge about Differential Pulse Code Modulation.
It contains the basics of Pulse Code modulation and why we all switching to Differential Pulse Code Modulation.
All the things about the Differential Pulse Code Modulation is given in a good understandable way
This document discusses various digital modulation techniques used in digital communications. It describes amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK) including binary PSK (BPSK) and quadrature PSK (QPSK). It provides block diagrams and explanations of modulators and demodulators for ASK, FSK, BPSK and QPSK. It also discusses M-ary encoding techniques that can transmit more than two bits simultaneously to reduce bandwidth.
1. Digital modulation techniques are used to modulate digital information so that it can be transmitted via different mediums. Common digital modulation methods include binary amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying (PSK).
2. FSK conveys information by changing the instantaneous frequency of a carrier wave. It is less susceptible to errors than ASK but has a larger spectrum bandwidth. PSK varies the phase of the transmitted signal. BPSK uses two phases while QPSK uses four phases.
3. The performance of digital modulation techniques can be compared using the energy per bit to noise power spectral density ratio (Eb/N0). Lower Eb/N0 values
This document discusses convolutional codes. It defines basic concepts like constraint length and generator polynomials that define convolutional codes. It describes representations of convolutional codes using state diagrams and trellis diagrams. It also discusses decoding convolutional codes using the Viterbi algorithm, which finds the most likely path through the trellis. The document concludes by discussing properties of convolutional codes like free distance, which is the minimum Hamming distance between codewords.
This document discusses optical time division multiplexing (OTDM) systems. It outlines some of the key challenges with OTDM, including nonlinearity in fibers causing signal-to-noise ratio degradation as the number of channels increases. It also discusses the components needed for an OTDM system, including ultra-short optical pulse generation and modulation at the transmitter, and optical clock extraction and demultiplexing at the receiver. Several approaches for OTDM demultiplexing are described, such as using cascaded modulators, nonlinear optical loop mirrors, or four wave mixing in a nonlinear medium.
The document discusses different techniques to mitigate fading in wireless channels. It describes slow flat fading, frequency selective fading, and fast fading. To mitigate slow flat fading, the document discusses diversity which uses multiple independent fading paths. It explains different types of diversity including space, frequency, and time diversity. It also discusses diversity combining techniques such as selection, equal gain, and maximal ratio combining which combine signals from multiple diversity paths. The document aims to explain how to combat different types of fading in wireless channels.
This document discusses digital T-carriers and multiplexing. It describes various multiplexing techniques including time division multiplexing, frequency division multiplexing, and wavelength division multiplexing. It also discusses T1 digital carriers which carry 24 channels of digital data at 1.544 Mbps using time division multiplexing. Channel banks are used to convert analog signals to digital signals to be carried on T-carrier lines. Fractional T-carriers allow customers to purchase less than the full 24 channels of a T1. The document also covers digital signal hierarchy and uses of digital terminals for voice, data, pictures and video.
The document discusses hierarchical modulation, which allows multiple data streams to be modulated into a single symbol stream. It provides benefits like different quality of service levels and backward compatibility. Specifically, it examines hierarchical QPSK/16QAM modulation used in digital television broadcasting. It analyzes the power and bit error rate penalties experienced by legacy QPSK receivers in a hierarchical system due to the addition of a secondary information stream. Research refinements like rotated constellations in DVB-T2 and concatenated coding are also discussed.
In digital modulation, minimum-shift keying(MSK) is a type of continuous-phase frequency-shift keying that was developed in the late 1950s and 1960s.
Similar to OQPSK(Offset quadrature phase-shift keying),
This document provides an overview of digital signal processors (DSPs). It defines a DSP as an integrated circuit designed for high-speed data manipulation used in applications such as audio, communications, and image processing. The document discusses how DSPs work by converting analog signals to digital signals and processing them. It explains that DSPs are needed because they can perform multiplication and division faster than general-purpose processors. The rest of the document details the architecture of DSPs, examples of DSP chip families like TMS320, and how instruction pipelining is implemented on the TMS320C54X DSP processor.
The most fundamental digital modulation techniques are based on keying: PSK (phase-shift keying): a finite number of phases are used. FSK (frequency-shift keying): a finite number of frequencies are used. ... QAM (quadrature amplitude modulation): a finite number of at least two phases and at least two amplitudes are used.
5. analog to digital conversion. ( pcm ,dm with short descriptions )MdFazleRabbi18
This document discusses two techniques for analog-to-digital conversion: pulse code modulation (PCM) and delta modulation. PCM samples an analog signal at regular intervals, quantizes the signal levels into discrete values, then encodes the samples into a digital bitstream using pulse amplitude modulation. Delta modulation encodes the differences between samples rather than their absolute values, sending a "1" if the value increases and a "0" if it decreases. Both techniques allow analog signals to be represented digitally but PCM works better for signals with small changes while delta modulation is better suited to signals with larger variations between samples.
The document summarizes various digital modulation and demodulation schemes used in wireless communication systems. It describes the structure of a basic wireless communication link and then provides details about modulation formats such as BPSK, DPSK, QPSK, OQPSK, and π/4 QPSK. It explains the key aspects of each scheme such as symbol mapping, transmitter and receiver operations, and their advantages over other schemes in terms of spectral efficiency and robustness to noise and fading channels.
Gaussian Minimum Shift Keying (GMSK) is a form of continuous-phase frequency shift keying that uses a Gaussian filter to generate a constant envelope signal. It provides better spectral efficiency than MSK through bandwidth reduction while maintaining low intersymbol interference. GMSK is used widely in wireless technologies like GSM and CDPD due to its power efficiency and good bit error rate performance compared to other modulation schemes. While more spectrally efficient than MSK, GMSK also has slightly higher error rates and requires more complex receivers.
Digital modulation techniques change aspects of a carrier signal to transmit information. This document discusses various digital modulation methods including:
- Amplitude modulation (AM) which varies the amplitude (A) of the carrier.
- Frequency modulation (FM) which varies the frequency (ω) of the carrier.
- Phase modulation (PM) which varies the phase (φ) of the carrier.
It then discusses specific modulation techniques including amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK) and their variants like quadrature phase shift keying (QPSK). The document provides illustrations of the modulated signals and discusses their bandwidth efficiency and performance in noise.
Amplitude Shift Keying (ASK) is a modulation technique where the amplitude of a carrier signal is varied according to the amplitude levels of a digital signal. In ASK, a digital signal of 1s and 0s is multiplied with a carrier signal, with a 1 having no effect on the carrier signal but a 0 reducing the carrier signal amplitude to zero. ASK has high efficiency and low noise interference but also high bandwidth and power consumption, making it suitable for applications like satellite links.
The document discusses various topics related to digital communication systems including:
- Advantages of digital over analog communication systems such as noise immunity and easier implementation of error control coding.
- The process of analog to digital conversion including sampling, quantization, encoding, and pulse code modulation (PCM).
- Digital modulation techniques like differential PCM (DPCM) and delta modulation (DM) that reduce redundancy before encoding.
- Considerations for line coding binary data onto an analog channel such as bandwidth, noise immunity, power efficiency and self-clocking capability.
Quadrature amplitude modulation (QAM) is a modulation technique that encodes data by changing both the amplitude and phase of carrier waves. It allows more data to be transmitted over a given bandwidth compared to techniques that only vary the amplitude or phase. QAM modulators use two carrier waves shifted in phase by 90 degrees that are modulated by separate data streams before being combined. Higher order QAM schemes use constellations with more points that allow more bits to be encoded per symbol. While this improves bandwidth efficiency, it also makes the system more susceptible to noise. QAM is widely used in technologies like DSL, wireless networks, cable TV, and microwave backhaul systems.
Bit error rate (BER) is a measure of the error probability in a digital transmission system. It is defined as the ratio of wrongly received bits to the total number of transmitted bits. A low BER is necessary for reliable digital communication. BER can be measured using a bit error rate tester which transmits a test pattern and counts the number of errors. BER is affected by noise and interference in the transmission channel. Noisy or burst errors are more difficult to correct than random errors. BER is an important parameter to characterize the quality and reliability of a communication system.
Phase-shift keying (PSK) is a digital modulation technique that conveys data by changing the phase of a carrier wave. There are several types of PSK including binary PSK (BPSK) and quadrature PSK (QPSK). BPSK uses two phases separated by 180 degrees to transmit 1 bit per symbol, while QPSK uses four phases separated by 90 degrees to transmit 2 bits per symbol for higher data rates. PSK has advantages like more efficient data transmission compared to frequency-shift keying. However, it is non-coherent and more prone to incorrect demodulations. PSK finds applications in optical communications, local oscillators, and delay-and-add demodulation.
A Brief Knowledge about Differential Pulse Code Modulation.
It contains the basics of Pulse Code modulation and why we all switching to Differential Pulse Code Modulation.
All the things about the Differential Pulse Code Modulation is given in a good understandable way
This document discusses various digital modulation techniques used in digital communications. It describes amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK) including binary PSK (BPSK) and quadrature PSK (QPSK). It provides block diagrams and explanations of modulators and demodulators for ASK, FSK, BPSK and QPSK. It also discusses M-ary encoding techniques that can transmit more than two bits simultaneously to reduce bandwidth.
1. Digital modulation techniques are used to modulate digital information so that it can be transmitted via different mediums. Common digital modulation methods include binary amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying (PSK).
2. FSK conveys information by changing the instantaneous frequency of a carrier wave. It is less susceptible to errors than ASK but has a larger spectrum bandwidth. PSK varies the phase of the transmitted signal. BPSK uses two phases while QPSK uses four phases.
3. The performance of digital modulation techniques can be compared using the energy per bit to noise power spectral density ratio (Eb/N0). Lower Eb/N0 values
This document discusses convolutional codes. It defines basic concepts like constraint length and generator polynomials that define convolutional codes. It describes representations of convolutional codes using state diagrams and trellis diagrams. It also discusses decoding convolutional codes using the Viterbi algorithm, which finds the most likely path through the trellis. The document concludes by discussing properties of convolutional codes like free distance, which is the minimum Hamming distance between codewords.
This document discusses optical time division multiplexing (OTDM) systems. It outlines some of the key challenges with OTDM, including nonlinearity in fibers causing signal-to-noise ratio degradation as the number of channels increases. It also discusses the components needed for an OTDM system, including ultra-short optical pulse generation and modulation at the transmitter, and optical clock extraction and demultiplexing at the receiver. Several approaches for OTDM demultiplexing are described, such as using cascaded modulators, nonlinear optical loop mirrors, or four wave mixing in a nonlinear medium.
The document discusses different techniques to mitigate fading in wireless channels. It describes slow flat fading, frequency selective fading, and fast fading. To mitigate slow flat fading, the document discusses diversity which uses multiple independent fading paths. It explains different types of diversity including space, frequency, and time diversity. It also discusses diversity combining techniques such as selection, equal gain, and maximal ratio combining which combine signals from multiple diversity paths. The document aims to explain how to combat different types of fading in wireless channels.
This document discusses digital T-carriers and multiplexing. It describes various multiplexing techniques including time division multiplexing, frequency division multiplexing, and wavelength division multiplexing. It also discusses T1 digital carriers which carry 24 channels of digital data at 1.544 Mbps using time division multiplexing. Channel banks are used to convert analog signals to digital signals to be carried on T-carrier lines. Fractional T-carriers allow customers to purchase less than the full 24 channels of a T1. The document also covers digital signal hierarchy and uses of digital terminals for voice, data, pictures and video.
The document discusses hierarchical modulation, which allows multiple data streams to be modulated into a single symbol stream. It provides benefits like different quality of service levels and backward compatibility. Specifically, it examines hierarchical QPSK/16QAM modulation used in digital television broadcasting. It analyzes the power and bit error rate penalties experienced by legacy QPSK receivers in a hierarchical system due to the addition of a secondary information stream. Research refinements like rotated constellations in DVB-T2 and concatenated coding are also discussed.
Lecture Notes: EEEC6440315 Communication Systems - Spectral EfficiencyAIMST University
This document discusses methods for improving spectral efficiency in communication systems. It provides information on different modulation techniques and factors that influence spectral efficiency, such as signal-to-noise ratio, bandwidth efficiency, forward error correction, data compression, and MIMO. It also describes how modulation and demodulation are implemented using software-defined radios and digital signal processing. The pursuit of greater spectral efficiency is important given the finite amount of radio spectrum and growing demand for wireless services.
Cross-Layer Design of Raptor Codes for Video Multicast over 802.11n MIMO Chan...Berna Bulut
This document summarizes a study on using Raptor codes in a cross-layer design for transmitting video over 802.11n MIMO channels. It presented a methodology to select the optimal transmission scheme (SM or STBC), modulation and coding scheme, and Raptor code rate based on channel conditions to minimize transmission time while maintaining low packet error rates. Simulation results showed that Raptor codes can improve performance by enabling higher order modulation at lower SNRs and reducing transmission times, especially in high spatial correlation conditions.
This document appears to be an assignment on link adaptation and adaptive modulation and coding. It contains chapters on coding gain and BER, modulation gain and BER, adapting energy per bit, adapting coding technique, and adapting modulation technique. It also includes algorithms and flow charts for adapting energy per bit and coding/modulation techniques. The goal is to dynamically select modulation, coding, and transmission power based on changing channel conditions to optimize throughput while maintaining a target BER.
Experimental Evaluation of Large Scale WiFi Multicast Rate Control, By: Varun...Belal Essam ElDiwany
The document presents the Multicast Dynamic Rate Adaptation (MuDRA) algorithm for improving WiFi multicast performance at scale. MuDRA aims to maximize throughput while meeting quality requirements for a high percentage of receivers. It selects a small number of receivers to provide feedback and dynamically adapts the transmission rate based on their reports. Experimental results on a 150+ node testbed show that MuDRA achieves higher throughput than other schemes while still satisfying quality thresholds for most receivers.
Signal Alignment: Enabling Physical Layer Network Coding for MIMO NetworkingAishwary Singh
This document discusses physical layer network coding with signal alignment (PNC-SA) for improving transmission strategies in two-way relay channels. It explains how PNC-SA allows multiple packets to be simultaneously transmitted and received through precoding vectors that align signals at access points. The document compares the bit error rate and throughput of PNC-SA to other techniques. It also explores applications of PNC-SA like information exchange, cross unicasts, multi-sender multicast, and multi-hop broadcast in MIMO wireless networks.
Design and analysis of different digital communication systems and determinat...eSAT Journals
This document summarizes the design and analysis of different digital communication systems to determine the optimal system. It discusses the design processes for binary amplitude shift keying (BASK), binary phase shift keying (BPSK), and binary frequency shift keying (BFSK) systems. Simulation results are presented for the BASK system, showing the input, modulated, and output signals. The document aims to identify the best digital communication system considering parameters like error performance, signal-to-noise ratio, and bandwidth.
Design and analysis of different digital communication systems and determinat...eSAT Journals
Abstract For a specialized device or set-up in case of any practical communication related problem definition, a sound communication system consisting of the necessary integral parts is very crucial. As such, the design and an analysis of the various communication system is very critical as it directly effects the performance of the device and also reveals the inherent capacity of the system to produce the desired results. In this respect our topic for this paper is the design and analysis of different digital communication systems with a view to determine the most effective system considering all the parameters so that it can be used for important communication based problems and situations. In the next section we will mainly focus on the design processes of various systems, the theory involved, the simulation results, some special techniques of error correction and also the error performance of the systems. Keywords- modulation, digital, communication systems, shift keying, error performance, SNR
Design and analysis of different digital communication systems and determinat...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Nanotechnology based satellite communication systemSarah Christy
Nanotechnology based satellite communication system
The document discusses nanosatellite communication systems. It describes how early systems had simple transmitters but now support more data for scientific missions. Higher frequencies allow more data but require more complex hardware. Modern systems use modulation schemes like QPSK for better spectrum efficiency. Channel coding and software-defined radios further improve performance. Future systems may use deployable solar arrays for more power and higher data rates over 1 Mbps via advanced techniques.
WiFi-802.11g -Adaptivity of modulation mode and encoding rate for an improved...Michael Xevgenis
This document summarizes an experiment analyzing the adaptivity of modulation mode and error correction coding rate in 802.11g wireless networks based on channel conditions. The experiment measured signal strength and throughput at different locations in an indoor environment. Simulation results modeling different modulation modes and coding rates under varying noise levels were also presented and compared to experimental measurements. The analysis found that more robust modulation/coding combinations were selected in noisier channel conditions to maintain reliability and throughput. Adding an additional access point was recommended to further improve quality of service for users.
unit_5 ppt DIRECT BROADCAST SATELLITE.pptxrubini Rubini
The document discusses satellite navigation systems and direct broadcast satellite technology. For satellite navigation, the key benefits are enhanced safety, increased capacity, and reduced delays. Direct broadcast satellites provide audio, video, television and internet services directly to homes. They operate in the Ku band and use techniques like MPEG compression, forward error correction, and circular polarization of signals to transmit multiple channels via each transponder.
The paper discuses about the performance of digital modulation schemes – BPSK, QPSK and QAM using
MATLAB. The performance of these schemes is evaluated by finding the bit error rate (BER) on AWGN and
Rayleigh channels. Initially a MATLAB code is generated and the performance of these modulation schemes
BPSK,QPSK and QAM is evaluated by finding BER and signal to noise ratio over AWGN and Rayleigh fading
channels. Later a simulation model is created using Simulink for these modulation schemes and its performance is
evaluated on AWGN channel.
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2. AGENDA
• Hierarchical Modulation (HM), a closer view.
• HM vs. Non-HM.
• Why HM ?
• HM in the real life.
• HM Scheme.
• Hp stream vs. LP stream.
• HM System Parameters.
• Power Penalty Analysis.
• BER Penalty Analysis.
• Research Refinements in hierarchical modulation.
10 Feb. 2016
3. BEFORE WE START..
• TV technology revolutions: analog color TV, digital TV.
• Digital TV is based on digital data compression and digital data transmission.
• In 1993,The DVB project was founded in Europe as an industry-led consortium of
around 200 broadcasters, manufacturers, network operators, software developers,
regulatory bodies and others committed to designing open interoperable standards
for the global delivery of digital media and broadcast services.
10 Feb. 2016
4. BEFORE WE START..
• DVB Standards help us to know framing structure, channel coding and modulation for
digital television.
• These DVB standards are the technical basis for implementing digital TV
transmission.
10 Feb. 2016
5. HIERARCHICAL
MODULATION,
A CLOSER
VIEW
• Hierarchical modulation, also called layered modulation, is one of the signal
processing techniques for multiplexing and modulating multiple data streams into
one single symbol stream.
• Such multiple streams are called:
- High priority (HP) stream, Low priority (LP) stream, or
- Basic Information, secondary information, or
- Basic layer, enhancement layer, or
- Coarse information, refinement information.
10 Feb. 2016
6. HIERARCHICAL
MODULATION,
A CLOSER
VIEW
• Although hierarchical modulation can be applied to any constellations, we will limit
our discussions to QPSK/16QAM hierarchical modulation.
• The reason is two fold:
- First, most digital satellite systems use QPSK,
- Secondly, the use of a specific hierarchical constellation, QPSK/16QAM in this
case, simplifies the analysis.
10 Feb. 2016
8. WHY HM ?
• Hierarchical modulations can help:
• provide different QoS to users with different profiles, e.g. higher throughput for
users with advanced receiver.
10 Feb. 2016
9. WHY HM ?
• provide unequal protection on different contents, e.g., video, audio, text.
• upgrade system to provide better service to new users with advanced receivers
while keeping existing users unchanged (Backward Compatibility,“the upgrade is
transparent to the deployed receivers of the original system”).
10 Feb. 2016
10. WHY HM ?
• Hierarchical modulation is particularly used to mitigate the cliff effect in digital
television broadcast, particularly mobile TV, by providing a (lower quality) fallback
signal in case of weak signals, allowing graceful degradation instead of complete
signal loss.
10 Feb. 2016
11. HM IN THE REAL LIFE
Hierarchical modulations are widely used in digital
broadcast system design such as:
• DVB-T.
• Media-FLO (Forward Link Only), a digital broadcast TV
system developed by Qualcomm for mobile television.
• UMB (Ultra Mobile Broadband), a new 3.5th generation
mobile network standard developed by 3GPP2.
• Under study for DVB-H.
10 Feb. 2016
12. HM SCHEME
• hb
• The basic and secondary information bits
are channel encoded.
• The coded basic information bits are
mapped to the QPSK constellation.
• 𝑑min(𝐻𝑃) = 2𝑑1.
• The basic hierarchical constellation is
next modified according to the coded
secondary information bits.
• The combined constellation is a 16-QAM
constellation with the minimum distance
between two points denoted by 2𝑑2 .
• The two blocks, QPSK Mapper and
Secondary Mapper, in the Figure may be
combined into one.
10 Feb. 2016
13. HP STREAM VS. LP STREAM
• Specify the quadrant number (1,2,3, or 4).
• Lower code rate (higher protected).
• larger service coverage areas.
• Lower bit rate.
• Specify the symbol’s location within the
quadrant.
• higher code rate (lower protected).
• Smaller service coverage areas.
• Higher bit rate.
10 Feb. 2016
14. HM SYSTEM PARAMETERS
• Three parameters are required to describe a hierarchical modulation scheme:
- The ratio of the minimum distances in the hierarchical, basic constellations,
called Hierarchy Parameter λ, where λ =
𝒅 𝟐
𝒅 𝟏
.
- Code rates for the HP and LP streams.
- Modulation order for the HP and LP streams.
• λ is an important parameter to characterize the system, analysis are provided for it.
10 Feb. 2016
15. PENALTY ANALYSIS
• The light will be focused on the penalty
analysis performed in the paper shown in
the next figure.
• We will consider for two types of penalties
introduced to the QPSK receivers in the
hierarchical systems,
- Power penalty,
- BER penalty.
10 Feb. 2016
16. POWER PENALTY ANALYSIS
• When λ is small, the four points in each quadrant of the constellation
form a “cloud”.
• To the originally designed receivers,a cloud represents a point in the
QPSK constellation.
• Therefore, QPSK receivers in the upgraded system will continue to
operate and receive the basic information bits, but at a higher noise
level.
• The additional noise imposes a penalty on the performance of
originally designed receivers.
10 Feb. 2016
17. POWER PENALTY ANALYSIS
• The carrier to noise ratio (CNR) of the hierarchical constellation of Figure (b) is given by:
𝑪𝑵𝑹 =
𝑬 𝒔
𝑵 𝒐
=
𝟐𝒅 𝟏
𝟐
+ 𝟐𝒅 𝟐
𝟐
𝑵 𝒐
• When signals with the hierarchical constellation of Figure (b) are received by the QPSK
receivers, the constellation is treated as QPSK constellation, with power 2 𝑑1
2
.
• To these receivers, the noise consists of two terms, the channel noise 𝑁𝑜, and the scattering
of points in the secondary hierarchy constellation, 2λ2
𝑑1
2
(2 𝑑2
2
).
• The modulation noise ratio (MNR) is introduced to be the ratio of the power of QPSK
constellation to the combined noise power, and it is given by:
𝑴𝑵𝑹 =
2 𝒅 𝟏
𝟐
𝑵 𝒐+𝟐λ 𝟐 𝒅 𝟏
𝟐 =
𝑪𝑵𝑹
𝟏+ 𝟏+λ 𝟐 𝑪𝑵𝑹
• MNR is the actual SNR seen by the QPSK receivers in hierarchical systems.
10 Feb. 2016
18. POWER PENALTY ANALYSIS
• The penalty to the QPSK receivers 𝑃 𝑀𝑁𝑅 is the ratio
𝐶𝑁𝑅
𝑀𝑁𝑅
, which is
𝑷 𝑴𝑵𝑹= 𝟏 + 𝟏 + λ 𝟐 𝑪𝑵𝑹
• The penalty, a function of both λ and CNR,is a measure of how much the QPSK
receivers suffer due to the addition of the secondary information, it represents the
additional carrier power that is needed in the hierarchical system so that the QPSK
receivers can see the same cleanness of the constellation as in the QPSK system
• The larger the penalty is, the worse these receivers will perform in the hierarchical
system.
10 Feb. 2016
19. POWER PENALTY ANALYSIS
Our Simulations Authors’ Simulations
For λ = 0.1 , when the transmission power in the hierarchical
system has a 7dB CNR, the QPSK receivers effectively get a
QPSK constellation with equivalence of CNR = 6.75dB,
because the penalty is 0.25dB. 10 Feb. 2016
20. BER PENALTY ANALYSIS
• In the QPSK system, the QPSK constellation is transmitted and the probability of bit
error is : 𝑩𝑬𝑹 𝑄𝑃𝑆𝐾 = 𝑸 𝑪𝑵𝑹
• The probability of raw bit error (without error correction coding) made by the QPSK
receivers in the hierarchical system is given by (performed by Vitthaladevuni et al.),
𝑩𝑬𝑹 =
𝟏
𝟐
𝑸
𝟏 − 𝝀
𝟏 + 𝝀 𝟐
𝑪𝑵𝑹 +
𝟏
𝟐
𝑸
𝟏 + 𝝀
𝟏 + 𝝀 𝟐
𝑪𝑵𝑹
• A comparison of the last two equations reveals that, for a given CNR, the addition of
the secondary information bits in the hierarchical system causes the QPSK receivers
to have a larger BER, and hence introduces a penalty to these receivers.
10 Feb. 2016
21. BER PENALTY ANALYSIS
• This penalty in BER is denoted as 𝑷 𝐵𝐸𝑅, and is defined by the following equation:
𝑸
𝑪𝑵𝑹
𝑷 𝐵𝐸𝑅
=
𝟏
𝟐
𝑸
𝟏 − 𝝀
𝟏 + 𝝀 𝟐
𝑪𝑵𝑹 +
𝟏
𝟐
𝑸
𝟏 + 𝝀
𝟏 + 𝝀 𝟐
𝑪𝑵𝑹
• The BER penalty 𝑷 𝐵𝐸𝑅, also a function of 𝝀 and CNR, represents the additional carrier
power that is needed in the hierarchical system so that the QPSK receivers can have
the same BER as in QPSK system without the secondary information.
10 Feb. 2016
23. RESEARCH REFINEMENTS IN
HIERARCHICAL MODULATION
• The Rotated constellation, one of
the main innovations in the DVB-T2
standard.
• It is an optional feature to improve
performance in frequency selective
channels.
• Angle of Rotation is a big challenge in
such a refinement.
10 Feb. 2016
24. RESEARCH REFINEMENTS IN
HIERARCHICAL MODULATION
• concatenated coding strategy : mixing the two streams in order to make the
encoding of the LP stream dependent on the well protected HP stream.
• Improve the LP decoding performance while keeping the HP decoding
performance unchanged.
10 Feb. 2016
25. REFERENCES
• Hong Jiang and Paul Wilford,“A Hierarchical Modulation for Upgrading Digital Broadcast
Systems”, IEEE Transactions on Broadcasting, vol. 51, no. 2, 2005, pp. 223-229.
• Alexander Schertz and Chris Weck,“Hierarchical modulation - The transmission of two independent
DVBT multiplexes on a single frequency”, EBU Technical Review, April 2003.
• Shu Wang, Soonyil Kwon and Sukwoo Lee, LG Electronics Mobile Research, USA“On Enhancing
Hierarchical Modulations”, CONFERENCE PAPER ,JANUARY 2008.
• “Hierarchical modulation”,Wikipedia.
• DVB Fact Sheet - May 2014.
• Hugo Meric, Jerome Lacan, Fabrice Arnal, Guy Lesthievent and Marie-Laure Boucheret,“Combining
Adaptive Coding and Modulation with Hierarchical Modulation in Satcom Systems”, IEEE
TRANSACTIONS ON BROADCASTING,DECEMBER 2011.
• Seyed Mohammad Sajad Sadough and Pierre Duhamel,“On the Interaction Between Channel
Coding and Hierarchical Modulation”, an IEEE ICC 2009 proceedings candidate.
• Ladislav Polak,Tomas Kratochvil,“Performance of the Rotated Constellation in DVB-T2”, ICDT 2012.
10 Feb. 2016