This document discusses a modified coding technique to reduce peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It begins by introducing the PAPR problem in OFDM and existing solutions using Golay complementary sequences (GCS). It then presents definitions and theorems regarding recursive Golay complementary codes (RGCC) that can provide codewords with low PAPR. The paper proposes generating a 16-QAM OFDM signal from QPSK Golay complementary pairs using RGCC to achieve both higher coding rate and lower PAPR compared to existing techniques.
FR1.L09 - PREDICTIVE QUANTIZATION OF DECHIRPED SPOTLIGHT-MODE SAR RAW DATA IN...grssieee
This document presents methods for predictive quantization of dechirped spotlight-mode synthetic aperture radar (SAR) raw data in the transform domain. It discusses previous work on SAR data compression, analyzes the characteristics of spotlight SAR data in the inverse discrete Fourier transform (IDFT) domain, and proposes three predictive encoding schemes - transform domain block predictive quantization (TD-BPQ), transform domain block predictive vector quantization (TD-BPVQ), and predictive trellis coded quantization (TD-PTCQ) - to take advantage of correlations in the transformed data. Numerical results on an example dataset show SNR improvements of up to 6 dB compared to baseline block adaptive quantization.
The document discusses IP load balancing across multiple packet blades to handle high throughput traffic. Load must be shared symmetrically across blades to ensure individual users and flows are always directed to the same blade. Common load balancing methods like direct association and statistical approaches are outlined. The advantages of using an ATCA switch like the FlexCore FM40 for load balancing are presented, including its ability to identify users, filter unwanted traffic, and insert VLAN tags to precisely target packets.
This document proposes an OFDM receiver capable of estimating and correcting the subcarrier dependent Doppler shifting on a symbol-by-symbol basis for highly mobile underwater acoustic networks. It presents a receiver structure that estimates the Doppler rate for each OFDM symbol based on the recovered data from the previous symbol, allowing for compensation of changing Doppler rates. Two algorithms are developed for the symbol-by-symbol Doppler rate estimation: one ad-hoc and one based on the marginal maximum likelihood principle. Simulation results show the receiver design performs well for a source accelerating at 0.29 m/s^2.
Extended summary of nonorthogonal random access for 5g mobile communication s...ChristianPoloDelVecc
The document presents two Nonorthogonal Random Access (NORA) systems - NORA-A and NORA-B - for 5G networks proposed in a research paper. NORA allows multiple users to share the same bandwidth simultaneously by transmitting packets at one of two power levels, P1 or P2. The base station uses Successive Interference Cancellation to receive and decode packets. Simulation results show that NORA-B achieves higher throughput than NORA-A or traditional S-ALOHA by optimizing transmission probabilities based on user numbers. The maximum throughput of NORA-B reaches 0.65 packets per time slot.
LAR uses location information to reduce routing overhead in mobile ad hoc networks. It minimizes the search zone for route discovery by using the expected zone based on the destination's last known location and speed. The route request is restricted to this request zone to limit flooding. Variations include alternative definitions of the request zone and allowing intermediate nodes to update the zone based on more recent location data or initiate local repair if a route breaks. Simulation results show LAR performs better than flooding in networks with varying node speeds, transmission ranges, densities, and location errors.
A Chain condition for operators from C(K)-spacesKp Hart
The document discusses weakly compact operators from C(K)-spaces and introduces a chain condition, stating that an operator T: C(K) → X is not weakly compact if there exists an infinite δ-chain in C(K) where the infimum of Tf - Tg is positive for all pairs in the chain; it also notes that uncountable δ-chains are common in function spaces like C[0,1] and provides an example constructing an uncountable δ-chain in this space.
H-8PSK is a hierarchical modulation technique specified in the DVB-S2 standard that allows two transport streams to be transmitted simultaneously on a single transponder. The high priority stream is modulated using QPSK, while the low priority stream's bits are used to modulate an additional phase shift. This provides backward compatibility, as standard DVB receivers can demodulate the high priority stream, while receivers compatible with H-8PSK are needed to decode the low priority stream. In practice, H-8PSK has remained a niche technology, with few actual broadcasts using it reported.
This document discusses a modified coding technique to reduce peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It begins by introducing the PAPR problem in OFDM and existing solutions using Golay complementary sequences (GCS). It then presents definitions and theorems regarding recursive Golay complementary codes (RGCC) that can provide codewords with low PAPR. The paper proposes generating a 16-QAM OFDM signal from QPSK Golay complementary pairs using RGCC to achieve both higher coding rate and lower PAPR compared to existing techniques.
FR1.L09 - PREDICTIVE QUANTIZATION OF DECHIRPED SPOTLIGHT-MODE SAR RAW DATA IN...grssieee
This document presents methods for predictive quantization of dechirped spotlight-mode synthetic aperture radar (SAR) raw data in the transform domain. It discusses previous work on SAR data compression, analyzes the characteristics of spotlight SAR data in the inverse discrete Fourier transform (IDFT) domain, and proposes three predictive encoding schemes - transform domain block predictive quantization (TD-BPQ), transform domain block predictive vector quantization (TD-BPVQ), and predictive trellis coded quantization (TD-PTCQ) - to take advantage of correlations in the transformed data. Numerical results on an example dataset show SNR improvements of up to 6 dB compared to baseline block adaptive quantization.
The document discusses IP load balancing across multiple packet blades to handle high throughput traffic. Load must be shared symmetrically across blades to ensure individual users and flows are always directed to the same blade. Common load balancing methods like direct association and statistical approaches are outlined. The advantages of using an ATCA switch like the FlexCore FM40 for load balancing are presented, including its ability to identify users, filter unwanted traffic, and insert VLAN tags to precisely target packets.
This document proposes an OFDM receiver capable of estimating and correcting the subcarrier dependent Doppler shifting on a symbol-by-symbol basis for highly mobile underwater acoustic networks. It presents a receiver structure that estimates the Doppler rate for each OFDM symbol based on the recovered data from the previous symbol, allowing for compensation of changing Doppler rates. Two algorithms are developed for the symbol-by-symbol Doppler rate estimation: one ad-hoc and one based on the marginal maximum likelihood principle. Simulation results show the receiver design performs well for a source accelerating at 0.29 m/s^2.
Extended summary of nonorthogonal random access for 5g mobile communication s...ChristianPoloDelVecc
The document presents two Nonorthogonal Random Access (NORA) systems - NORA-A and NORA-B - for 5G networks proposed in a research paper. NORA allows multiple users to share the same bandwidth simultaneously by transmitting packets at one of two power levels, P1 or P2. The base station uses Successive Interference Cancellation to receive and decode packets. Simulation results show that NORA-B achieves higher throughput than NORA-A or traditional S-ALOHA by optimizing transmission probabilities based on user numbers. The maximum throughput of NORA-B reaches 0.65 packets per time slot.
LAR uses location information to reduce routing overhead in mobile ad hoc networks. It minimizes the search zone for route discovery by using the expected zone based on the destination's last known location and speed. The route request is restricted to this request zone to limit flooding. Variations include alternative definitions of the request zone and allowing intermediate nodes to update the zone based on more recent location data or initiate local repair if a route breaks. Simulation results show LAR performs better than flooding in networks with varying node speeds, transmission ranges, densities, and location errors.
A Chain condition for operators from C(K)-spacesKp Hart
The document discusses weakly compact operators from C(K)-spaces and introduces a chain condition, stating that an operator T: C(K) → X is not weakly compact if there exists an infinite δ-chain in C(K) where the infimum of Tf - Tg is positive for all pairs in the chain; it also notes that uncountable δ-chains are common in function spaces like C[0,1] and provides an example constructing an uncountable δ-chain in this space.
H-8PSK is a hierarchical modulation technique specified in the DVB-S2 standard that allows two transport streams to be transmitted simultaneously on a single transponder. The high priority stream is modulated using QPSK, while the low priority stream's bits are used to modulate an additional phase shift. This provides backward compatibility, as standard DVB receivers can demodulate the high priority stream, while receivers compatible with H-8PSK are needed to decode the low priority stream. In practice, H-8PSK has remained a niche technology, with few actual broadcasts using it reported.
This document compares the Selected Mapping (SLM) and Partial Transmit Sequence (PTS) techniques for reducing peak-to-average power ratio (PAPR) in multicarrier code division multiple access (MC-CDMA) systems. Through MATLAB simulations, the authors found that:
1) PTS partitions the input data block into disjoint subblocks, weights the subcarriers in each subblock with phase factors, and selects the combination with the lowest PAPR for transmission.
2) SLM generates multiple alternative signals by multiplying the input with different phase sequences before inverse fast Fourier transform. It selects the signal with the lowest PAPR for transmission.
3) PTS has lower computational
Suppression of Chirp Interferers in GPS Using the Fractional Fourier TransformCSCJournals
In this paper we apply the Fractional Fourier Transform (FrFT) to remove chirp interferers that corrupt Global Positioning System (GPS) signals. The concept is based on the fact that in the time-frequency plane, known as the Wigner Distribution (WD), chirps are represented as lines. Using an FrFT with some rotational parameter ‘a’, we rotate to a new time axis ta that transforms the chirp to a tone, in which the energy of the tone is contained in usually just one or two samples. The best `a', and the correct time sample along the ta axis, may be found without a priori knowledge by searching for the peak in the FrFT, since compression to one or two time samples results in an energy spike. Once the peak is found, we zero out the tone, and hence the underlying chirp. Rotation back to the original time domain via an inverse FrFT produces an improved GPS signal. This method can apply to multiple chirp interferers, and we describe how to easily determine the number of interferers, K, by finding peaks in the FrFT space over the parameter `a'. We also describe how to easily notch the interferers once converted to tones by computing a threshold based on the power of the coarse acquisition (C/A) code and noise. We show that for signal-to-noise ratios (SNRs) greater than at least 10 dB, interferers can be notched regardless of the ratio of the C/A code power to the combined interferer power, denoted as carrier-to-interference ratio (CIR).
The document discusses several speech compression techniques:
1) Uncompressed audio rates are 64kbps for voice and 1.5Mbps for CD audio.
2) ADPCM reduces the data rate to 32kbps by transmitting differences between predicted and actual sample values.
3) SB-ADPCM splits audio into lower and upper sub-bands, compressing each at different rates (48kbps and 16kbps respectively) for total of 64kbps.
4) LPC represents speech as a combination of previous samples and residual error, transmitting just coefficients, enabling lower rates like those in GSM and other standards.
The document discusses applications and simulations of error correction coding (ECC) for multicast file transfer. It provides an overview of different ECC and feedback-based multicast protocols and evaluates their performance based on simulations. Reed-Solomon coding on blocks provided faster decoding times than on entire files, while tornado coding had the fastest decoding but required slightly more packets for reconstruction. Simulations of protocols like MFTP and MFTP/EC using network simulators showed that using ECC like Reed-Muller codes significantly improved performance over regular MFTP.
goGPS is open source software that improves the accuracy of low-cost GPS devices through real-time kinematic (RTK) positioning and Kalman filtering. It was initially developed through 2007-2009 at the Polytechnic of Milan and Osaka City University. The software provides sub-meter level positioning and is being ported from MATLAB to Java to manage it as a collaborative open source project. goGPS processing will also be offered as a web service to provide accurate positioning from raw GPS data. Future work includes expanding supported signals and sensors and developing hardware to run the software-defined radio front-end.
A Closed-Form Expression for Queuing Delay in Rayleigh Fading Channels Using ...Giacomo Verticale
This document is a research paper that uses stochastic network calculus to model a wireless channel subject to Rayleigh fading and obtain an approximate closed-form expression for the probability tail of queuing delay. The paper presents the Markovian model of the Rayleigh fading channel, discusses the spectral gap in Markov chains and stochastic network calculus. It then derives the service envelope of the fading channel and compares the queuing delay expression to simulation results, finding a good match between the analysis and simulations. The conclusion is that stochastic network calculus can be used to successfully study wireless channels.
This document discusses performance modeling of MAC layer protocols. It develops equations to evaluate the performance of MAC strategies based on metrics like transmission time, throughput, offered traffic, and transfer delay. The document assumes a generic multi-access network with Poisson packet arrivals and derives formulas for TDMA, ALOHA, slotted ALOHA, and CSMA strategies. It also defines concepts like stability, waiting time, and normalized average transfer delay.
This document discusses channel estimation techniques in OFDM systems. It compares LS and MMSE estimation methods. It also describes simulating an OFDM transmission in Matlab to analyze how the bit error ratio is affected by changing the signal-to-noise ratio and multipath effects. The key steps of the simulation are outlined, including OFDM transmission, channel estimation using LS and MMSE, and calculating the bit error ratio to compare performance of the estimation techniques.
This document summarizes research on reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It discusses using a companding technique with Gaussian distribution to compress the signal before transmission and decompress it upon reception. The key aspects covered are: applying a compander and decompander with Gaussian distribution parameters at the transmitter and receiver; how the central limit theorem allows the sum of subcarriers to approximate a Gaussian distribution for large numbers; and how this technique reduces PAPR by increasing average power while keeping peak power the same. Performance is analyzed by simulating PAPR and bit error rate with and without companding under different parameters.
The document discusses algorithms for fault-tolerant broadcasts in asynchronous distributed systems. It begins by describing reliable broadcast, which ensures that if a correct process delivers a message, all correct processes will eventually deliver it. It then covers various enhancements like uniform reliable broadcast, FIFO reliable broadcast, and causal reliable broadcast. It also discusses how to implement atomic broadcast using consensus and how to transform different types of broadcasts into each other. Lastly, it provides an overview of the Paxos consensus algorithm.
The document discusses multipath propagation, RAKE receivers, and Gaussian Minimum Shift Keying (GMSK). It provides the following key points:
1) RAKE receivers were designed to equalize the effects of multipath propagation by using correlators, delays, and combining to separate multipath signals.
2) RAKE receivers combine symbols from different propagation paths using channel information and combining schemes like maximum ratio combining.
3) GMSK uses Gaussian filtering of minimum shift keying signals to achieve smooth phase transitions, reducing bandwidth requirements compared to minimum shift keying. However, it increases intersymbol interference.
The document discusses routing and wavelength assignment (RWA) in wavelength-division multiplexing (WDM) networks. It covers both static and dynamic RWA problems. For routing, it discusses integer linear programming formulations for static routing and online algorithms for dynamic routing. For wavelength assignment, it discusses graph coloring approaches for static assignment and heuristics like first-fit for dynamic assignment. Several heuristics for RWA are presented, along with their computational complexities and performance. Future research directions like survivable RWA and managing multicast connections are also outlined.
This document presents a design for an elastic buffer using tri-state buffers to reduce power consumption, area, and delay compared to an elastic buffer design using D flip-flops. It describes elastic buffer designs using D flip-flops and tri-state buffers, comparing their transistor counts, power, area, delay, and functionality. The proposed tri-state elastic buffer design is implemented using Cadence tools and shown to achieve a 48.68% reduction in total power, 5.62% reduction in delay, and 40.98% reduction in area over an elastic buffer design using D flip-flops.
A collaborative wireless sensor network routingambitlick
This document proposes a new routing scheme called node reliance for wireless sensor networks. Node reliance rates how much each node is relied upon for routing data from sources to sinks. Sources will route through nodes with low reliance ratings to avoid overusing critical nodes and maximize network lifetime. The scheme is evaluated using an example network and compared to other routing methods. Node reliance aims to reduce energy waste from disconnected sources by encouraging collaboration between sources in path selection.
Mobile antennae general Beamforming principles presentationPierre LARREGLE
The document discusses smart antennas and MAC protocols in mobile ad hoc networks. It covers topics such as:
1) System models and algorithms for optimum beamformer design and adaptive beamforming.
2) Direction-of-arrival estimation methods including MF, MVDR, and MUSIC.
3) Schemes using directional antennas in the MAC layer including Vaidya's scheme 1 which uses directional RTS and omnidirectional CTS.
The document describes the GPRS Tunnelling Protocol (GTP) used in 2G and 3G mobile networks. It discusses GTP interfaces and tunnels, message formats including the GTP header, and message groups. The key points are:
1. GTP is used between GPRS Support Nodes (GSNs) and between SGSN and RNC to tunnel user data packets and control signaling messages.
2. The GTP header contains fields for version, message type, length, TEID, and optional fields for sequence number and N-PDU number.
3. GTP messages are grouped into path management messages for path verification, tunnel management messages for context creation/deletion, and location/mobility management messages
An Efficient Data Collection Protocol for Underwater Wireless Sensor NetworksIJCNCJournal
This paper presents the design and evaluation of a new data collection protocol for Underwater Wireless Sensor Networks called the Data Collection Tree Protocol (DCTP). It uses an efficient distributed algorithm to proactively construct and maintain a data collection tree rooted at the sink node. The preconstructed and maintained data collection tree allows the efficient selection of a single forwarding node at each hop when routing a data packet. We prove the correctness of the constructed data collection tree and we show that under some stability conditions, the constructed tree converges to an optimal shortestpath tree. Results of extensive simulations show a big improvement in terms of packet delivery ratio, endto-end delay and energy consumption compared to the well-known VBF protocol. The simulated cases show increases in the packet delivery ratio between 20% and 122%, reductions in the average end-to-enddelay between 15% and 55% and reductions in the energy consumption between 20% and 50%. These results clearly demonstrate the attractiveness of the proposed DCTP protocol.
This document compares the Selected Mapping (SLM) and Partial Transmit Sequence (PTS) techniques for reducing peak-to-average power ratio (PAPR) in multicarrier code division multiple access (MC-CDMA) systems. Through MATLAB simulations, the authors found that:
1) PTS partitions the input data block into disjoint subblocks, weights the subcarriers in each subblock with phase factors, and selects the combination with the lowest PAPR for transmission.
2) SLM generates multiple alternative signals by multiplying the input with different phase sequences before inverse fast Fourier transform. It selects the signal with the lowest PAPR for transmission.
3) PTS has lower computational
Suppression of Chirp Interferers in GPS Using the Fractional Fourier TransformCSCJournals
In this paper we apply the Fractional Fourier Transform (FrFT) to remove chirp interferers that corrupt Global Positioning System (GPS) signals. The concept is based on the fact that in the time-frequency plane, known as the Wigner Distribution (WD), chirps are represented as lines. Using an FrFT with some rotational parameter ‘a’, we rotate to a new time axis ta that transforms the chirp to a tone, in which the energy of the tone is contained in usually just one or two samples. The best `a', and the correct time sample along the ta axis, may be found without a priori knowledge by searching for the peak in the FrFT, since compression to one or two time samples results in an energy spike. Once the peak is found, we zero out the tone, and hence the underlying chirp. Rotation back to the original time domain via an inverse FrFT produces an improved GPS signal. This method can apply to multiple chirp interferers, and we describe how to easily determine the number of interferers, K, by finding peaks in the FrFT space over the parameter `a'. We also describe how to easily notch the interferers once converted to tones by computing a threshold based on the power of the coarse acquisition (C/A) code and noise. We show that for signal-to-noise ratios (SNRs) greater than at least 10 dB, interferers can be notched regardless of the ratio of the C/A code power to the combined interferer power, denoted as carrier-to-interference ratio (CIR).
The document discusses several speech compression techniques:
1) Uncompressed audio rates are 64kbps for voice and 1.5Mbps for CD audio.
2) ADPCM reduces the data rate to 32kbps by transmitting differences between predicted and actual sample values.
3) SB-ADPCM splits audio into lower and upper sub-bands, compressing each at different rates (48kbps and 16kbps respectively) for total of 64kbps.
4) LPC represents speech as a combination of previous samples and residual error, transmitting just coefficients, enabling lower rates like those in GSM and other standards.
The document discusses applications and simulations of error correction coding (ECC) for multicast file transfer. It provides an overview of different ECC and feedback-based multicast protocols and evaluates their performance based on simulations. Reed-Solomon coding on blocks provided faster decoding times than on entire files, while tornado coding had the fastest decoding but required slightly more packets for reconstruction. Simulations of protocols like MFTP and MFTP/EC using network simulators showed that using ECC like Reed-Muller codes significantly improved performance over regular MFTP.
goGPS is open source software that improves the accuracy of low-cost GPS devices through real-time kinematic (RTK) positioning and Kalman filtering. It was initially developed through 2007-2009 at the Polytechnic of Milan and Osaka City University. The software provides sub-meter level positioning and is being ported from MATLAB to Java to manage it as a collaborative open source project. goGPS processing will also be offered as a web service to provide accurate positioning from raw GPS data. Future work includes expanding supported signals and sensors and developing hardware to run the software-defined radio front-end.
A Closed-Form Expression for Queuing Delay in Rayleigh Fading Channels Using ...Giacomo Verticale
This document is a research paper that uses stochastic network calculus to model a wireless channel subject to Rayleigh fading and obtain an approximate closed-form expression for the probability tail of queuing delay. The paper presents the Markovian model of the Rayleigh fading channel, discusses the spectral gap in Markov chains and stochastic network calculus. It then derives the service envelope of the fading channel and compares the queuing delay expression to simulation results, finding a good match between the analysis and simulations. The conclusion is that stochastic network calculus can be used to successfully study wireless channels.
This document discusses performance modeling of MAC layer protocols. It develops equations to evaluate the performance of MAC strategies based on metrics like transmission time, throughput, offered traffic, and transfer delay. The document assumes a generic multi-access network with Poisson packet arrivals and derives formulas for TDMA, ALOHA, slotted ALOHA, and CSMA strategies. It also defines concepts like stability, waiting time, and normalized average transfer delay.
This document discusses channel estimation techniques in OFDM systems. It compares LS and MMSE estimation methods. It also describes simulating an OFDM transmission in Matlab to analyze how the bit error ratio is affected by changing the signal-to-noise ratio and multipath effects. The key steps of the simulation are outlined, including OFDM transmission, channel estimation using LS and MMSE, and calculating the bit error ratio to compare performance of the estimation techniques.
This document summarizes research on reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It discusses using a companding technique with Gaussian distribution to compress the signal before transmission and decompress it upon reception. The key aspects covered are: applying a compander and decompander with Gaussian distribution parameters at the transmitter and receiver; how the central limit theorem allows the sum of subcarriers to approximate a Gaussian distribution for large numbers; and how this technique reduces PAPR by increasing average power while keeping peak power the same. Performance is analyzed by simulating PAPR and bit error rate with and without companding under different parameters.
The document discusses algorithms for fault-tolerant broadcasts in asynchronous distributed systems. It begins by describing reliable broadcast, which ensures that if a correct process delivers a message, all correct processes will eventually deliver it. It then covers various enhancements like uniform reliable broadcast, FIFO reliable broadcast, and causal reliable broadcast. It also discusses how to implement atomic broadcast using consensus and how to transform different types of broadcasts into each other. Lastly, it provides an overview of the Paxos consensus algorithm.
The document discusses multipath propagation, RAKE receivers, and Gaussian Minimum Shift Keying (GMSK). It provides the following key points:
1) RAKE receivers were designed to equalize the effects of multipath propagation by using correlators, delays, and combining to separate multipath signals.
2) RAKE receivers combine symbols from different propagation paths using channel information and combining schemes like maximum ratio combining.
3) GMSK uses Gaussian filtering of minimum shift keying signals to achieve smooth phase transitions, reducing bandwidth requirements compared to minimum shift keying. However, it increases intersymbol interference.
The document discusses routing and wavelength assignment (RWA) in wavelength-division multiplexing (WDM) networks. It covers both static and dynamic RWA problems. For routing, it discusses integer linear programming formulations for static routing and online algorithms for dynamic routing. For wavelength assignment, it discusses graph coloring approaches for static assignment and heuristics like first-fit for dynamic assignment. Several heuristics for RWA are presented, along with their computational complexities and performance. Future research directions like survivable RWA and managing multicast connections are also outlined.
This document presents a design for an elastic buffer using tri-state buffers to reduce power consumption, area, and delay compared to an elastic buffer design using D flip-flops. It describes elastic buffer designs using D flip-flops and tri-state buffers, comparing their transistor counts, power, area, delay, and functionality. The proposed tri-state elastic buffer design is implemented using Cadence tools and shown to achieve a 48.68% reduction in total power, 5.62% reduction in delay, and 40.98% reduction in area over an elastic buffer design using D flip-flops.
A collaborative wireless sensor network routingambitlick
This document proposes a new routing scheme called node reliance for wireless sensor networks. Node reliance rates how much each node is relied upon for routing data from sources to sinks. Sources will route through nodes with low reliance ratings to avoid overusing critical nodes and maximize network lifetime. The scheme is evaluated using an example network and compared to other routing methods. Node reliance aims to reduce energy waste from disconnected sources by encouraging collaboration between sources in path selection.
Mobile antennae general Beamforming principles presentationPierre LARREGLE
The document discusses smart antennas and MAC protocols in mobile ad hoc networks. It covers topics such as:
1) System models and algorithms for optimum beamformer design and adaptive beamforming.
2) Direction-of-arrival estimation methods including MF, MVDR, and MUSIC.
3) Schemes using directional antennas in the MAC layer including Vaidya's scheme 1 which uses directional RTS and omnidirectional CTS.
The document describes the GPRS Tunnelling Protocol (GTP) used in 2G and 3G mobile networks. It discusses GTP interfaces and tunnels, message formats including the GTP header, and message groups. The key points are:
1. GTP is used between GPRS Support Nodes (GSNs) and between SGSN and RNC to tunnel user data packets and control signaling messages.
2. The GTP header contains fields for version, message type, length, TEID, and optional fields for sequence number and N-PDU number.
3. GTP messages are grouped into path management messages for path verification, tunnel management messages for context creation/deletion, and location/mobility management messages
An Efficient Data Collection Protocol for Underwater Wireless Sensor NetworksIJCNCJournal
This paper presents the design and evaluation of a new data collection protocol for Underwater Wireless Sensor Networks called the Data Collection Tree Protocol (DCTP). It uses an efficient distributed algorithm to proactively construct and maintain a data collection tree rooted at the sink node. The preconstructed and maintained data collection tree allows the efficient selection of a single forwarding node at each hop when routing a data packet. We prove the correctness of the constructed data collection tree and we show that under some stability conditions, the constructed tree converges to an optimal shortestpath tree. Results of extensive simulations show a big improvement in terms of packet delivery ratio, endto-end delay and energy consumption compared to the well-known VBF protocol. The simulated cases show increases in the packet delivery ratio between 20% and 122%, reductions in the average end-to-enddelay between 15% and 55% and reductions in the energy consumption between 20% and 50%. These results clearly demonstrate the attractiveness of the proposed DCTP protocol.
GraphRAG for Life Science to increase LLM accuracyTomaz Bratanic
GraphRAG for life science domain, where you retriever information from biomedical knowledge graphs using LLMs to increase the accuracy and performance of generated answers
How to Interpret Trends in the Kalyan Rajdhani Mix Chart.pdfChart Kalyan
A Mix Chart displays historical data of numbers in a graphical or tabular form. The Kalyan Rajdhani Mix Chart specifically shows the results of a sequence of numbers over different periods.
Taking AI to the Next Level in Manufacturing.pdfssuserfac0301
Read Taking AI to the Next Level in Manufacturing to gain insights on AI adoption in the manufacturing industry, such as:
1. How quickly AI is being implemented in manufacturing.
2. Which barriers stand in the way of AI adoption.
3. How data quality and governance form the backbone of AI.
4. Organizational processes and structures that may inhibit effective AI adoption.
6. Ideas and approaches to help build your organization's AI strategy.
Your One-Stop Shop for Python Success: Top 10 US Python Development Providersakankshawande
Simplify your search for a reliable Python development partner! This list presents the top 10 trusted US providers offering comprehensive Python development services, ensuring your project's success from conception to completion.
Fueling AI with Great Data with Airbyte WebinarZilliz
This talk will focus on how to collect data from a variety of sources, leveraging this data for RAG and other GenAI use cases, and finally charting your course to productionalization.
Digital Marketing Trends in 2024 | Guide for Staying AheadWask
https://www.wask.co/ebooks/digital-marketing-trends-in-2024
Feeling lost in the digital marketing whirlwind of 2024? Technology is changing, consumer habits are evolving, and staying ahead of the curve feels like a never-ending pursuit. This e-book is your compass. Dive into actionable insights to handle the complexities of modern marketing. From hyper-personalization to the power of user-generated content, learn how to build long-term relationships with your audience and unlock the secrets to success in the ever-shifting digital landscape.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
Project Management Semester Long Project - Acuityjpupo2018
Acuity is an innovative learning app designed to transform the way you engage with knowledge. Powered by AI technology, Acuity takes complex topics and distills them into concise, interactive summaries that are easy to read & understand. Whether you're exploring the depths of quantum mechanics or seeking insight into historical events, Acuity provides the key information you need without the burden of lengthy texts.
AI 101: An Introduction to the Basics and Impact of Artificial IntelligenceIndexBug
Imagine a world where machines not only perform tasks but also learn, adapt, and make decisions. This is the promise of Artificial Intelligence (AI), a technology that's not just enhancing our lives but revolutionizing entire industries.
Introduction of Cybersecurity with OSS at Code Europe 2024Hiroshi SHIBATA
I develop the Ruby programming language, RubyGems, and Bundler, which are package managers for Ruby. Today, I will introduce how to enhance the security of your application using open-source software (OSS) examples from Ruby and RubyGems.
The first topic is CVE (Common Vulnerabilities and Exposures). I have published CVEs many times. But what exactly is a CVE? I'll provide a basic understanding of CVEs and explain how to detect and handle vulnerabilities in OSS.
Next, let's discuss package managers. Package managers play a critical role in the OSS ecosystem. I'll explain how to manage library dependencies in your application.
I'll share insights into how the Ruby and RubyGems core team works to keep our ecosystem safe. By the end of this talk, you'll have a better understanding of how to safeguard your code.
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Speck&Tech
ABSTRACT: A prima vista, un mattoncino Lego e la backdoor XZ potrebbero avere in comune il fatto di essere entrambi blocchi di costruzione, o dipendenze di progetti creativi e software. La realtà è che un mattoncino Lego e il caso della backdoor XZ hanno molto di più di tutto ciò in comune.
Partecipate alla presentazione per immergervi in una storia di interoperabilità, standard e formati aperti, per poi discutere del ruolo importante che i contributori hanno in una comunità open source sostenibile.
BIO: Sostenitrice del software libero e dei formati standard e aperti. È stata un membro attivo dei progetti Fedora e openSUSE e ha co-fondato l'Associazione LibreItalia dove è stata coinvolta in diversi eventi, migrazioni e formazione relativi a LibreOffice. In precedenza ha lavorato a migrazioni e corsi di formazione su LibreOffice per diverse amministrazioni pubbliche e privati. Da gennaio 2020 lavora in SUSE come Software Release Engineer per Uyuni e SUSE Manager e quando non segue la sua passione per i computer e per Geeko coltiva la sua curiosità per l'astronomia (da cui deriva il suo nickname deneb_alpha).
HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Main news related to the CCS TSI 2023 (2023/1695)Jakub Marek
An English 🇬🇧 translation of a presentation to the speech I gave about the main changes brought by CCS TSI 2023 at the biggest Czech conference on Communications and signalling systems on Railways, which was held in Clarion Hotel Olomouc from 7th to 9th November 2023 (konferenceszt.cz). Attended by around 500 participants and 200 on-line followers.
The original Czech 🇨🇿 version of the presentation can be found here: https://www.slideshare.net/slideshow/hlavni-novinky-souvisejici-s-ccs-tsi-2023-2023-1695/269688092 .
The videorecording (in Czech) from the presentation is available here: https://youtu.be/WzjJWm4IyPk?si=SImb06tuXGb30BEH .
Best 20 SEO Techniques To Improve Website Visibility In SERPPixlogix Infotech
Boost your website's visibility with proven SEO techniques! Our latest blog dives into essential strategies to enhance your online presence, increase traffic, and rank higher on search engines. From keyword optimization to quality content creation, learn how to make your site stand out in the crowded digital landscape. Discover actionable tips and expert insights to elevate your SEO game.
Generating privacy-protected synthetic data using Secludy and MilvusZilliz
During this demo, the founders of Secludy will demonstrate how their system utilizes Milvus to store and manipulate embeddings for generating privacy-protected synthetic data. Their approach not only maintains the confidentiality of the original data but also enhances the utility and scalability of LLMs under privacy constraints. Attendees, including machine learning engineers, data scientists, and data managers, will witness first-hand how Secludy's integration with Milvus empowers organizations to harness the power of LLMs securely and efficiently.
Generating privacy-protected synthetic data using Secludy and Milvus
Asilomar 2011
1. Spectrum Leasing via Cooperative
Opportunistic Routing in Distributed Ad Hoc
Networks: Optimal and Heuristic Policies
Cristiano Tapparello
Davide Chiarotto, Michele Rossi, Osvaldo
Simeone and Michele Zorzi
04/11/11
3. Cognitive Radio
¨ Coexistence
of:
q primary
network:
licensed
q secondary
network:
unlicensed
¨ Common
model:
q primary
users
are
oblivious
to
the
presence
of
secondary
users
q secondary
users
sense
the
radio
environment
in
search
of
spectrum
holes
q Performance
limited
by
sensing
errors
¨ Spectrum
leasing:
q primary
users
lease
part
of
the
(licensed)
spectrum
to
secondary
users
in
exchange
for
appropriate
remunera?on
Cristiano Tapparello – Asilomar 2011 04/11/11
4. Spectrum leasing via
cooperation [Simeone08]
¨ Remuneration is offered by the secondary users in the
form of cooperation (relaying)
¨ Secondary users accept to cooperate if leased
enough spectral resources to satisfy QoS requirements
Cristiano Tapparello – Asilomar 2011 04/11/11
5. Opportunistic routing
Po Pd
¨ Leverages broadcast nature of wireless channel
¨ Next hop selected in an adaptive manner, based on:
q current channel conditions (relay availability) [Larsson01]
q distance to destination [Zorzi03, Morris04]
q delay and congestion criteria [Javidi09]
Cristiano Tapparello – Asilomar 2011 04/11/11
6. Spectrum leasing via
opportunistic cooperative routing
= primary
= secondary
Po Pd
¨ Spectrum leasing with remuneration offered by secondary
network via forwarding
¨ Secondary nodes act as potential next hops
¨ Secondary nodes accept to cooperate if QoS requirements are
satisfied
Cristiano Tapparello – Asilomar 2011 04/11/11
8. System model
T = RP [ RS [ {Po , Pd }
Po Pd
¨ Primary Network: RP [ {Po , Pd }
¨ Secondary Network: RS
¨ Nodes are static and arbitrarily placed
¨ Nodes work in half-duplex mode, spatial reuse is not allowed
¨ ⇠P = EP /N0 : average received SNR between Po and Pd
¨ RP , RS : primary, secondary transmission rates [bits/s/Hz]
Cristiano Tapparello – Asilomar 2011 04/11/11
9. Problem formulation
Po a Pd
x
y
¨ State of the system x ✓ T : subset of nodes that have
correctly decoded the primary packet
¨ Action a 2 x : node selected to act as next-hop transmitter
¨ Next state y ◆ x : subset of nodes that have correctly
decoded the packet after the transmission from a 2 x
Cristiano Tapparello – Asilomar 2011 04/11/11
10. Transition probabilities
da,n
Po a Pd
x
y
¨ Depend on outage probabilities
¤ Primary transmitter:
✓ RP
◆
2 1
pout (da,n ) = 1 exp ⌘
⇠P da,n
Cristiano Tapparello – Asilomar 2011 04/11/11
11. Transition probabilities (2)
a
Po Pd
x
y
¨ Depend on outage probabilities
¤ Secondary transmitter uses superposition coding
n Superposition of primary and secondary packet
n Decoding based on two decoders in parallel: 1) treat undesired
packet as noise; 2) successive interference cancellation
Cristiano Tapparello – Asilomar 2011 04/11/11
12. Secondary QoS requirement
a
RS
dS
Po Pd
pout ✏S
x
y
¨ Secondary network QoS requirement Q = (dS , RS , ✏S )
¤ Transmission rate RS
¤ Maximum outage probability ✏S for a receiver located
no further than dS
Cristiano Tapparello – Asilomar 2011 04/11/11
13. Transition costs
a
Po Pd
x
y
¨ Each transition entails a cost:
c(x, a, y) = ↵cThr (x, a, y) + (1 ↵)cE (x, a, y)
¨ Primary end-to-end throughput cost:
cThr (x, a, y) = 1, 8 a 2 x
Cristiano Tapparello – Asilomar 2011 04/11/11
14. Transition costs (2)
a
Po Pd
x
y
¨ Each transition entails a cost:
c(x, a, y) = ↵cThr (x, a, y) + (1 ↵)cE (x, a, y)
¨ Primary energy cost:
(
1 when a 2 RP [ {Po }
cE (x, a, y) =
0 when a 2 RS
Cristiano Tapparello – Asilomar 2011 04/11/11
15. Optimal Routing Policies
¨ Starting state s and final state f
¨ Goal: minimize the total expected discounted cost
"+1 #
def
X
k
J(s) = E⇡ c(x, a, y) x0 = s , 0 < <1
k=0
¨ The problem is an instance of stochastic routing
[Lott06]
¨ The optimal policy is an index policy
¤ global ranking of the nodes
¨ A centralized algorithm and its distributed
implementation is provided in [Lott06]
Cristiano Tapparello – Asilomar 2011 04/11/11
16. Heuristic Routing Policies
¨ The algorithm in [Lott06] requires full knowledge of the
network topology and has time complexity O(|T |2 )
¨ We propose two low-complexity heuristic policies that
only require local topology information
¨ Suitable for a distributed implementation
¨ Relay selection is made on-line by the current
transmitter at each hop, based on local interactions
¨ Both policies uses a primary energy budget K to control
the trade-off between the primary energy consumption
and the end-to-end throughput
¤ maximum number of primary relays that can be used
¤ stored within the packet
¤ decremented when a new primary relay is selected
Cristiano Tapparello – Asilomar 2011 04/11/11
17. K-Closer
K>0
Po a Pd
K=0
¨ Nodes are ranked according to their distance from
the destination Pd
¨ Budget K to control primary energy consumption
Cristiano Tapparello – Asilomar 2011 04/11/11
18. K-Closer (2)
✔ Pros:
¤ Fully distributed and easy to implement
¤ Limited amount of information (ACK and NACK) and
overhead (residual energy budget K)
✗ Cons:
¤ The primary energy budget K potentially limits the
available multiuser diversity
¤ Can potentially select a relay with a small number of
neighbors in its proximity
Cristiano Tapparello – Asilomar 2011 04/11/11
19. K-One Step Look Ahead
(K-OSLA)
¨ K-OSLA improves K-Closer using an expected
geographical advancement metric
¨ Each node a knows its distance from the destination a
and shares it with other nodes
¨ Each node a builds the order sets:
¤ B(a) = n1 , n2 , . . . , n|B(a)| , with
ni+1 a , for i = 1, . . . , |B(a)| 1
ni
¤ B S (a) ✓ B(a) , which only contains secondary nodes
¨ ga,n = denotes the geographical advancement
a n
of a toward Pd provided by a relay n
Cristiano Tapparello – Asilomar 2011 04/11/11
20. K-OSLA (2)
¨ Expected geographical advancement metrics:
|B(a)| |B(a)|
X Y
¤ ga = ga,ni [1 pout (a, ni )] pout (a, nj )
i=1 j=i+1
|BS (a)| |BS (a)|
X Y
S
¤ ga = ga,mi [1 pout (a, mi )] pout (a, mj )
i=1 j=i+1
¨ At each hop, the possible relays are ranked according to
the metrics:
¤ Ga,n = ga,n + gn when K > 1
¤ Ga,n = ga,n + gn when K = 1 and a 2 RS
¤ GS = ga,n + gn otherwise
a,n
S
Cristiano Tapparello – Asilomar 2011 04/11/11
21. K-OSLA (3)
✔ Pros:
¤ Fullydistributed and easy to implement
¤ Prevents the packet to be forwarded towards
connectivity holes
✗ Cons:
¤ Requires exchange of additional information
S
¤ Additional pre-computation for gn and gn
¤ The energy budget K potentially limits the available
multiuser diversity
Cristiano Tapparello – Asilomar 2011 04/11/11
22. Numerical Results:
Optimal vs Heuristics
Optimal
0.6 K-OSLA
α=1 K-Closer
Optimal, No SL
0.5 K-OSLA, No SL
Throughput [bits/s/Hz]
K-Closer, No SL
K=8
0.4
0.3
α=0
0.2
K=0
0.1
0 2 4 6 8 10 12
Primary Energy [dB]
Cristiano Tapparello – Asilomar 2011 04/11/11
25. Conclusions
¨ Spectrum leasing solution to the problem of
coexistence of primary and secondary nodes
¨ The problem is formulated as a stochastic routing
problem to obtain optimal policies
¨ Two reduced complexity heuristics have been
proposed and they achieve close-to-optimal
performance
¨ Optimal and heuristic policies improve both primary
energy and throughput
Cristiano Tapparello – Asilomar 2011 04/11/11
26. Refences
¨ [Larsson01]: P. Larsson, “Selection Diversity Forwarding in a Multihop Packet Radio Network with
Fading Channel and Capture,” ACM SIGMOBILE Mob. Comput. Commun. Rev., vol. 5, no. 4, pp. 47–
54, Oct. 2001.
¨ [Zorzi03]: M. Zorzi and R. Rao, “Geographic random forwarding (GeRaF) for ad hoc and sensor
networks: multihop performance,” IEEE Trans. Mobile Comput., vol. 2, no. 4, pp. 337–348, Oct. 2003.
¨ [Morris04]: S. Biswas and R. Morris, “Opportunistic Routing in Multi-Hop Wireless Networks,” ACM
SIGCOMM Comput. Commun. Rev., vol. 34, no. 1, Jan. 2004.
¨ [Javidi09]: M. Naghshvar, H. Zhuang, and T. Javidi, “A General Class of Throughput Optimal Routing
Policies in Multi-hop Wireless Networks,” preprint, http://arxiv.org/pdf/0908.1273.
¨ [Chiarotto10]: D. Chiarotto, O. Simeone, M. Zorzi, ”Throughput and Energy Efficiency of Opportunistic
Routing with type-I HARQ in Linear Multihop Networks”, in Proc. of IEEE GlobeCom, Miami, FL, 6–10
Dec. 2010.
¨ [Simeone08]: O. Simeone, I. Stanojev, S. Savazzi, Y. Bar-Ness, U. Spagnolini, and R. Pickholtz,
“Spectrum Leasing to Cooperating Secondary Ad Hoc Networks,” IEEE J. Select. Areas Commun., vol.
26, no. 1, Jan. 2008.
¨ [Lott06]: C. Lott and D. Teneketzis, “Stochastic routing in ad hoc networks”, IEEE Transactions on
Automatic Control, vol. 51, no.1, Jan. 2006.
¨ [Chiarotto11]: D. Chiarotto, O. Simeone and M. Zorzi, “Spectrum leasing via cooperative
opportunistic routing”, IEEE Transactions on Wireless Communications, Vol. 10, no. 9, Sep. 2011
Cristiano Tapparello – Asilomar 2011 04/11/11
27. Spectrum Leasing via Cooperative
Opportunistic Routing in Distributed Ad Hoc
Networks: Optimal and Heuristic Policies
Cristiano Tapparello
Davide Chiarotto, Michele Rossi, Osvaldo
Simeone and Michele Zorzi
04/11/11
28. Optimal Routing Policies:
transition probabilities
8
>0
> (Pd 2 x or x = f ) and y 6= f
>
<1 (Pd 2 x or x = f ) and y = f
pxy (a) =
>0
> Pd 2 x, x 6= f and y = f
/
>
:
Pxy (a) Pd 2 x, x 6= f and y 6= f
/
Y Y
Pxy (a) = [1 pout (a, n)] pout (a, m)
n2T s.t. m2T s.t.
n2y,n2x
/ m2y
/
Cristiano Tapparello – Asilomar 2011 04/11/11
29. Secondary transmissions
h ⇣ ⌘i
(1) (2)
Pout,SP (da,n ) = 1 exp min HP , HP
(
(1)
1, 0 1 2 RP
HP = 2 RP 1 RP
(1 (1 )2RP )⇠ ⌘ , 1 2 < 1
S da,n
( n RS RP
o
(2) max (1 2 RS )⇠1 d ⌘ , 2⇠ d 1 , 0 <
⌘ <2 RS
HP = 2 S a,n S a,n
1, = 0 and 2 RS 1
Cristiano Tapparello – Asilomar 2011 04/11/11