Long Term Evolution (LTE) technologies include basic concepts such as traffic direction, transmission modes, and multiple-input multiple-output (MIMO) technologies. Key MIMO technologies allow multiple data streams to be transmitted simultaneously through multiple antennas to increase throughput, either for a single user via spatial multiplexing or for multiple users via multi-user MIMO. Antenna technologies such as directivity, radiation patterns, and diversity techniques are also discussed to enable directional transmission and reception of signals in LTE networks.
ECE 618 covers topics related to mobile and wireless communications including frequencies, signals, antennas, and multiplexing techniques. The course discusses frequency ranges used for mobile communication and how signals are represented. It also examines antenna types including isotropic radiators, dipoles, directed, and sectorized antennas. The document outlines multiplexing methods such as FDM, TDM, CDM and modulation schemes including ASK, FSK, PSK and their advantages.
This document summarizes key concepts about antennas and propagation. It discusses antenna types and properties like radiation patterns, gain, and effective area. It also covers propagation modes including ground wave, sky wave, and line-of-sight. Impairments like attenuation, noise, multipath, and fading are explained. Error compensation techniques like forward error correction, equalization, and diversity are also introduced.
This document discusses concepts related to electromagnetic signals and digital data transmission. It covers topics such as:
- Analog vs. digital signals and how they are represented over time.
- Key parameters of signals like amplitude, frequency, period, and phase.
- Relationships between bandwidth, data rate, and channel capacity for digital transmission.
- Different transmission media like guided (copper, fiber) and unguided (wireless) and their frequency ranges.
- Multiplexing techniques like frequency-division and time-division that allow multiple signals to be transmitted over a single medium.
This document contains notes from a chapter on transmission fundamentals from a textbook on wireless mobile computer networks. It discusses topics such as electromagnetic signals, time-domain concepts, frequency-domain concepts, analog vs digital signals and data, transmission media types, and multiplexing techniques. Specifically, it provides details on sine wave parameters, bandwidth, signal-to-noise ratio, Shannon capacity formula, classifications of transmission media including guided, unguided, radio frequency and microwave ranges, and examples of multiplexing including frequency-division and time-division.
A new bistatic Doppler measurement system was developed using an array receiving antenna with long element spacing, producing many sharp grating lobes. Digital beamforming processing is used to fill in the valleys between lobes, increasing received power across areas while reducing sidelobe contamination effects. An initial field test was conducted in Okinawa using a software radio receiver, though antenna gain was limited. An improved array antenna with higher gain is now being constructed.
This document discusses various topics related to antennas and propagation, including:
- The basic functions of antennas for transmission and reception of signals
- Types of radiation and reception patterns that characterize antenna performance
- Common types of antennas like dipole, vertical, and parabolic reflective antennas
- Factors that influence signal propagation over distance like free space loss, noise, multipath interference, and atmospheric effects
- Techniques to improve reliability like diversity combining, adaptive equalization, and forward error correction coding.
Wireless Communication and Networking by WilliamStallings Chap2Senthil Kanth
Hai I'm Senthilkanth, doing MCA in Mepco Schlenk Engineering College..
The following presentation covers topic called Wireless Communication and Networking
by WilliamStallings for BSc CS, BCA, MSc CS, MCA, ME students.Make use of it.
Wireless Communication and Networking
by WilliamStallings Chapter : 2Transmission Fundamentals
Chapter 2
Electromagnetic Signal
Function of time
Can also be expressed as a function of frequency
Signal consists of components of different frequencies
Time-Domain Concepts
Analog signal - signal intensity varies in a smooth fashion over time
No breaks or discontinuities in the signal
Digital signal - signal intensity maintains a constant level for some period of time and then changes to another constant level
Periodic signal - analog or digital signal pattern that repeats over time
s(t +T ) = s(t ) -¥< t < +¥
where T is the period of the signal
Time-Domain Concepts
Aperiodic signal - analog or digital signal pattern that doesn't repeat over time
Peak amplitude (A) - maximum value or strength of the signal over time; typically measured in volts
Frequency (f )
Rate, in cycles per second, or Hertz (Hz) at which the signal repeats
Time-Domain Concepts
Period (T ) - amount of time it takes for one repetition of the signal
T = 1/f
Phase () - measure of the relative position in time within a single period of a signal
Wavelength () - distance occupied by a single cycle of the signal
Or, the distance between two points of corresponding phase of two consecutive cycles
Sine Wave Parameters
General sine wave
s(t ) = A sin(2ft + )
Figure 2.3 shows the effect of varying each of the three parameters
(a) A = 1, f = 1 Hz, = 0; thus T = 1s
(b) Reduced peak amplitude; A=0.5
(c) Increased frequency; f = 2, thus T = ½
(d) Phase shift; = /4 radians (45 degrees)
note: 2 radians = 360° = 1 period
Sine Wave Parameters
Time vs. Distance
When the horizontal axis is time, as in Figure 2.3, graphs display the value of a signal at a given point in space as a function of time
With the horizontal axis in space, graphs display the value of a signal at a given point in time as a function of distance
At a particular instant of time, the intensity of the signal varies as a function of distance from the source
Frequency-Domain Concepts
Fundamental frequency - when all frequency components of a signal are integer multiples of one frequency, it’s referred to as the fundamental frequency
Spectrum - range of frequencies that a signal contains
Absolute bandwidth - width of the spectrum of a signal
Effective bandwidth (or just bandwidth) - narrow band of frequencies that most of the signal’s energy is contained in
Frequency-Domain Concepts
Any electromagnetic signal can be shown to consist of a collection of periodic analog signals (sine waves) at different amplitudes, frequencies, and phases
The period of the total signal is equal to the period of the fundamenta
ECE 618 covers topics related to mobile and wireless communications including frequencies, signals, antennas, and multiplexing techniques. The course discusses frequency ranges used for mobile communication and how signals are represented. It also examines antenna types including isotropic radiators, dipoles, directed, and sectorized antennas. The document outlines multiplexing methods such as FDM, TDM, CDM and modulation schemes including ASK, FSK, PSK and their advantages.
This document summarizes key concepts about antennas and propagation. It discusses antenna types and properties like radiation patterns, gain, and effective area. It also covers propagation modes including ground wave, sky wave, and line-of-sight. Impairments like attenuation, noise, multipath, and fading are explained. Error compensation techniques like forward error correction, equalization, and diversity are also introduced.
This document discusses concepts related to electromagnetic signals and digital data transmission. It covers topics such as:
- Analog vs. digital signals and how they are represented over time.
- Key parameters of signals like amplitude, frequency, period, and phase.
- Relationships between bandwidth, data rate, and channel capacity for digital transmission.
- Different transmission media like guided (copper, fiber) and unguided (wireless) and their frequency ranges.
- Multiplexing techniques like frequency-division and time-division that allow multiple signals to be transmitted over a single medium.
This document contains notes from a chapter on transmission fundamentals from a textbook on wireless mobile computer networks. It discusses topics such as electromagnetic signals, time-domain concepts, frequency-domain concepts, analog vs digital signals and data, transmission media types, and multiplexing techniques. Specifically, it provides details on sine wave parameters, bandwidth, signal-to-noise ratio, Shannon capacity formula, classifications of transmission media including guided, unguided, radio frequency and microwave ranges, and examples of multiplexing including frequency-division and time-division.
A new bistatic Doppler measurement system was developed using an array receiving antenna with long element spacing, producing many sharp grating lobes. Digital beamforming processing is used to fill in the valleys between lobes, increasing received power across areas while reducing sidelobe contamination effects. An initial field test was conducted in Okinawa using a software radio receiver, though antenna gain was limited. An improved array antenna with higher gain is now being constructed.
This document discusses various topics related to antennas and propagation, including:
- The basic functions of antennas for transmission and reception of signals
- Types of radiation and reception patterns that characterize antenna performance
- Common types of antennas like dipole, vertical, and parabolic reflective antennas
- Factors that influence signal propagation over distance like free space loss, noise, multipath interference, and atmospheric effects
- Techniques to improve reliability like diversity combining, adaptive equalization, and forward error correction coding.
Wireless Communication and Networking by WilliamStallings Chap2Senthil Kanth
Hai I'm Senthilkanth, doing MCA in Mepco Schlenk Engineering College..
The following presentation covers topic called Wireless Communication and Networking
by WilliamStallings for BSc CS, BCA, MSc CS, MCA, ME students.Make use of it.
Wireless Communication and Networking
by WilliamStallings Chapter : 2Transmission Fundamentals
Chapter 2
Electromagnetic Signal
Function of time
Can also be expressed as a function of frequency
Signal consists of components of different frequencies
Time-Domain Concepts
Analog signal - signal intensity varies in a smooth fashion over time
No breaks or discontinuities in the signal
Digital signal - signal intensity maintains a constant level for some period of time and then changes to another constant level
Periodic signal - analog or digital signal pattern that repeats over time
s(t +T ) = s(t ) -¥< t < +¥
where T is the period of the signal
Time-Domain Concepts
Aperiodic signal - analog or digital signal pattern that doesn't repeat over time
Peak amplitude (A) - maximum value or strength of the signal over time; typically measured in volts
Frequency (f )
Rate, in cycles per second, or Hertz (Hz) at which the signal repeats
Time-Domain Concepts
Period (T ) - amount of time it takes for one repetition of the signal
T = 1/f
Phase () - measure of the relative position in time within a single period of a signal
Wavelength () - distance occupied by a single cycle of the signal
Or, the distance between two points of corresponding phase of two consecutive cycles
Sine Wave Parameters
General sine wave
s(t ) = A sin(2ft + )
Figure 2.3 shows the effect of varying each of the three parameters
(a) A = 1, f = 1 Hz, = 0; thus T = 1s
(b) Reduced peak amplitude; A=0.5
(c) Increased frequency; f = 2, thus T = ½
(d) Phase shift; = /4 radians (45 degrees)
note: 2 radians = 360° = 1 period
Sine Wave Parameters
Time vs. Distance
When the horizontal axis is time, as in Figure 2.3, graphs display the value of a signal at a given point in space as a function of time
With the horizontal axis in space, graphs display the value of a signal at a given point in time as a function of distance
At a particular instant of time, the intensity of the signal varies as a function of distance from the source
Frequency-Domain Concepts
Fundamental frequency - when all frequency components of a signal are integer multiples of one frequency, it’s referred to as the fundamental frequency
Spectrum - range of frequencies that a signal contains
Absolute bandwidth - width of the spectrum of a signal
Effective bandwidth (or just bandwidth) - narrow band of frequencies that most of the signal’s energy is contained in
Frequency-Domain Concepts
Any electromagnetic signal can be shown to consist of a collection of periodic analog signals (sine waves) at different amplitudes, frequencies, and phases
The period of the total signal is equal to the period of the fundamenta
This document discusses radio frequency (RF) propagation and link budget analysis. It begins by describing the basic components of a transmission system including the transmitter, propagation path, and receiver. It then covers concepts such as free space path loss, antenna gain, effective isotropic radiated power (EIRP), and the near and far field regions. The document also presents models for calculating path loss in different environments, including the free space and Hata models. It concludes by explaining how link budget analysis can be used to determine the maximum allowable path loss between transmitter and receiver given their power levels, antenna gains, losses, and receiver sensitivity.
This document provides an overview of GSM link budget calculations. It defines key terms used in link budgets such as effective radiated power, antenna gain, diversity gain, receiver sensitivity, path loss, and fade margin. It explains the objectives of calculating a link budget are to estimate maximum allowable path loss, compute required effective isotropically radiated power for a balanced link, estimate coverage design thresholds, and evaluate technology performance. It also provides examples of uplink and downlink link budget calculations for a GSM network and defines indoor, in-car, and outdoor coverage requirements.
This document provides an introduction to key concepts in wireless communication systems. It outlines the main elements of a wireless system including the transmitter, frequency spectrum, modulation, antenna, propagation medium, and receiver. It also discusses wireless history, services, frequency bands, antenna characteristics, signal attenuation and noise. Common modulation techniques like AM, FM, ASK, FSK, PSK and QAM are introduced. The document also covers concepts of multipath propagation, signal-to-noise ratio, and multiplexing methods including TDM, FDM and CDMA.
MIMO systems use multiple antennas at both the transmitter and receiver to improve wireless communication performance. By utilizing spatial diversity and spatial multiplexing, MIMO can increase data rates and spectral efficiency without additional bandwidth or power. It also provides diversity gain to combat fading and improve quality of service. Key techniques of MIMO include spatial multiplexing to increase capacity through multiple parallel data streams, and spatial diversity to improve signal quality through redundant transmission paths. MIMO systems show promise to achieve high data rates over wireless channels and help meet the growing demand for wireless network performance.
This document provides an overview of key concepts in antennas and propagation. It defines an antenna as a device that transmits or receives electromagnetic waves. It describes common antenna types like dipoles and parabolic reflectors. It also covers topics like radiation patterns, antenna gain, propagation modes (ground wave, sky wave, line-of-sight), free space loss, noise, multipath, and techniques to mitigate signal degradation like diversity and error correction.
This document provides information on designing satellite communication links. It discusses key factors that influence system design such as frequency band, propagation effects, and multiple access techniques. The performance objectives and parameters of earth stations and satellites are outlined. Methods for calculating noise temperature, link budgets, and overall C/N ratio are presented. The document provides examples of designing links using different satellite systems and frequency bands.
This document summarizes key concepts about antennas and propagation. It discusses the basic functions and types of antennas, including radiation patterns and gain. It also covers propagation modes like ground-wave, sky-wave and line-of-sight. Factors that affect transmission like free space loss, noise and multipath interference are explained. Error compensation techniques such as forward error correction, equalization and diversity are also summarized.
The document discusses key aspects of wireless communication reference models including:
1. It describes the layers of the reference model from the physical layer up to the application layer and their main functions.
2. It covers topics like frequency ranges used for wireless transmission, common modulation techniques, and effects of signal propagation like multipath propagation.
3. It discusses technologies and standards used for wireless networks and regulations set by organizations like ITU.
1) The document discusses small-scale fading in mobile radio propagation. Small-scale fading is caused by multipath propagation and describes rapid fluctuations in a radio signal over a short time period or travel distance.
2) It introduces the impulse response model used to model multipath channels. The received signal is a combination of multipath components that arrive at different times with different amplitudes and phases.
3) It discusses parameters used to characterize mobile multipath channels including mean excess delay, RMS delay spread, maximum excess delay, coherence bandwidth, Doppler spread, and coherence time. These parameters describe the time dispersion and time-varying nature of the channel.
Introduction to basics of wireless networks such as
• Radio waves & wireless signal encoding techniques
• Wireless networking issues & constraints
• Wireless internetworking devices
This document provides an overview of wireless networks and technologies. It discusses the history of wireless communication from Marconi's invention of the wireless telegraph to modern cellular networks. It also covers key topics in wireless networking including broadband wireless, antennas and propagation, transmission impairments like noise and multipath, and error compensation techniques like forward error correction and diversity. The document is an introduction to wireless concepts for students intended to provide foundational knowledge.
This document provides an overview of wireless channel and radio propagation concepts. It discusses topics like electromagnetic spectrum, frequency and wavelength, decibels, gain and attenuation, wireless communication systems, signal-to-noise ratio, bandwidth, Shannon capacity, Nyquist bandwidth, radio propagation models including path loss, shadowing, multipath fading, and specific models like two-ray ground model, Okumura-Hata model, and COST-231 model. Examples are provided to illustrate key concepts and formulas around Shannon capacity, Nyquist bandwidth, and radio propagation models.
1) Diversity techniques in mobile wireless systems take advantage of multiple propagation paths to improve reliability by creating independent fading channels and combining the signals.
2) Common diversity techniques include space, time, frequency, angle, and polarization diversity which are created using multiple antennas, frequency bands, time slots, antenna angles or polarizations.
3) A Rake receiver is used to implement path diversity, capturing multipath signal energy with fingers tuned to peaks in the delay profile and maximizing ratio combining.
This document discusses advanced wireless communication technologies and their evolution over time to meet increasing data rate demands. It covers:
1) How wireless spectrum has become crowded as usage has increased, challenging engineers to develop technologies to achieve higher data rates within limited spectrum.
2) The evolution of mobile communication standards from 1G analog to 2G digital systems like GSM, and then 3G technologies like UMTS that supported data rates up to 384kbps.
3) Emerging 4G technologies aimed to support rates over 20Mbps using techniques like MIMO, adaptive modulation, and OFDM to more efficiently use available spectrum.
This document provides an overview of key concepts in antennas and propagation. It defines an antenna as a device that transmits or receives electromagnetic waves. It describes common antenna types like dipoles and parabolic reflectors. It also covers topics like radiation patterns, antenna gain, propagation modes (ground wave, sky wave, line-of-sight), factors that affect signal strength over distance like free space loss and multipath, and techniques to mitigate noise and fading like diversity and error correction.
This document summarizes different transmission media used for communication including guided media like twisted pair, coaxial cable, and optical fiber as well as unguided wireless transmission. It discusses characteristics of each medium such as bandwidth, attenuation, delay, and repeater spacing. Key concerns for any transmission include data rate, distance, and impairments from attenuation and interference. The document also provides tables comparing specifications of different cable categories and wavelength bands for optical fiber.
This document provides an overview of radio frequency (RF) antennas, including their fundamental characteristics and types. It describes how antennas transmit and receive signals, key antenna properties like gain and beamwidth, and different antenna types and configurations. It also addresses signal coverage problems and strategies for overcoming them, as well as how to perform return loss and antenna gain measurements.
Multiple Input Multiple Output (MIMO) technology uses multiple antennas at both the transmitter and receiver to improve channel robustness and throughput. By utilizing reflected signals, MIMO can provide gains in channel robustness and throughput. MIMO was initially developed in the 1990s after additional processing power made it possible to utilize both spatial diversity and spatial multiplexing. MIMO systems provide either spatial multiplexing gain to maximize transmission rate or diversity gain to minimize errors and prioritize reliability. MIMO is now used in many wireless communication standards and ongoing research aims to develop more advanced MIMO techniques.
This presentation deals with topics such as Electromagnetic Spectrum, Wireless Propagation, Signals, Signal propagation effects, Spread spectrum and cellular systems.
Access the video from this presentation for free from
http://www.rohde-schwarz-usa.com/DebuggingEMISS_On-Demand.html
Overview:
Electromagnetic interference is increasingly becoming a problem in complex systems that must interoperate in both digital and RF domains. When failures due to EMI occur it is often difficult to track down the sources of such failures using standard test receivers and spectrum analyzers. The unique ability of real-time spectrum analysis and synchronous time domain signal acquisition to capture transient events can quickly reveals details about the sources of EMI.
What You Will Learn:
How to isolate and analyze sources of EMI using an oscilloscope
Measurement considerations for correlating time and frequency domains
Near field probing basics
Presented By:
Dave Rishavy, Product Manager Oscilloscopes, Rohde & Schwarz
Dave Rishavy has a BS in Electrical Engineering from Florida State University and an MBA from the University of Colorado. Prior to joining Rohde and Schwarz, Mr. Rishavy gained over 15 years of experience in the test and measurement field at Agilent Technologies. This included positions in a wide range of technical marketing areas such as application engineering, product marketing, marketing management and strategic product planning. While at Agilent, Dave led the marketing and industry segment teams for the Infiniium line of oscilloscopes as well as high end logic analysis.
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
This document discusses radio frequency (RF) propagation and link budget analysis. It begins by describing the basic components of a transmission system including the transmitter, propagation path, and receiver. It then covers concepts such as free space path loss, antenna gain, effective isotropic radiated power (EIRP), and the near and far field regions. The document also presents models for calculating path loss in different environments, including the free space and Hata models. It concludes by explaining how link budget analysis can be used to determine the maximum allowable path loss between transmitter and receiver given their power levels, antenna gains, losses, and receiver sensitivity.
This document provides an overview of GSM link budget calculations. It defines key terms used in link budgets such as effective radiated power, antenna gain, diversity gain, receiver sensitivity, path loss, and fade margin. It explains the objectives of calculating a link budget are to estimate maximum allowable path loss, compute required effective isotropically radiated power for a balanced link, estimate coverage design thresholds, and evaluate technology performance. It also provides examples of uplink and downlink link budget calculations for a GSM network and defines indoor, in-car, and outdoor coverage requirements.
This document provides an introduction to key concepts in wireless communication systems. It outlines the main elements of a wireless system including the transmitter, frequency spectrum, modulation, antenna, propagation medium, and receiver. It also discusses wireless history, services, frequency bands, antenna characteristics, signal attenuation and noise. Common modulation techniques like AM, FM, ASK, FSK, PSK and QAM are introduced. The document also covers concepts of multipath propagation, signal-to-noise ratio, and multiplexing methods including TDM, FDM and CDMA.
MIMO systems use multiple antennas at both the transmitter and receiver to improve wireless communication performance. By utilizing spatial diversity and spatial multiplexing, MIMO can increase data rates and spectral efficiency without additional bandwidth or power. It also provides diversity gain to combat fading and improve quality of service. Key techniques of MIMO include spatial multiplexing to increase capacity through multiple parallel data streams, and spatial diversity to improve signal quality through redundant transmission paths. MIMO systems show promise to achieve high data rates over wireless channels and help meet the growing demand for wireless network performance.
This document provides an overview of key concepts in antennas and propagation. It defines an antenna as a device that transmits or receives electromagnetic waves. It describes common antenna types like dipoles and parabolic reflectors. It also covers topics like radiation patterns, antenna gain, propagation modes (ground wave, sky wave, line-of-sight), free space loss, noise, multipath, and techniques to mitigate signal degradation like diversity and error correction.
This document provides information on designing satellite communication links. It discusses key factors that influence system design such as frequency band, propagation effects, and multiple access techniques. The performance objectives and parameters of earth stations and satellites are outlined. Methods for calculating noise temperature, link budgets, and overall C/N ratio are presented. The document provides examples of designing links using different satellite systems and frequency bands.
This document summarizes key concepts about antennas and propagation. It discusses the basic functions and types of antennas, including radiation patterns and gain. It also covers propagation modes like ground-wave, sky-wave and line-of-sight. Factors that affect transmission like free space loss, noise and multipath interference are explained. Error compensation techniques such as forward error correction, equalization and diversity are also summarized.
The document discusses key aspects of wireless communication reference models including:
1. It describes the layers of the reference model from the physical layer up to the application layer and their main functions.
2. It covers topics like frequency ranges used for wireless transmission, common modulation techniques, and effects of signal propagation like multipath propagation.
3. It discusses technologies and standards used for wireless networks and regulations set by organizations like ITU.
1) The document discusses small-scale fading in mobile radio propagation. Small-scale fading is caused by multipath propagation and describes rapid fluctuations in a radio signal over a short time period or travel distance.
2) It introduces the impulse response model used to model multipath channels. The received signal is a combination of multipath components that arrive at different times with different amplitudes and phases.
3) It discusses parameters used to characterize mobile multipath channels including mean excess delay, RMS delay spread, maximum excess delay, coherence bandwidth, Doppler spread, and coherence time. These parameters describe the time dispersion and time-varying nature of the channel.
Introduction to basics of wireless networks such as
• Radio waves & wireless signal encoding techniques
• Wireless networking issues & constraints
• Wireless internetworking devices
This document provides an overview of wireless networks and technologies. It discusses the history of wireless communication from Marconi's invention of the wireless telegraph to modern cellular networks. It also covers key topics in wireless networking including broadband wireless, antennas and propagation, transmission impairments like noise and multipath, and error compensation techniques like forward error correction and diversity. The document is an introduction to wireless concepts for students intended to provide foundational knowledge.
This document provides an overview of wireless channel and radio propagation concepts. It discusses topics like electromagnetic spectrum, frequency and wavelength, decibels, gain and attenuation, wireless communication systems, signal-to-noise ratio, bandwidth, Shannon capacity, Nyquist bandwidth, radio propagation models including path loss, shadowing, multipath fading, and specific models like two-ray ground model, Okumura-Hata model, and COST-231 model. Examples are provided to illustrate key concepts and formulas around Shannon capacity, Nyquist bandwidth, and radio propagation models.
1) Diversity techniques in mobile wireless systems take advantage of multiple propagation paths to improve reliability by creating independent fading channels and combining the signals.
2) Common diversity techniques include space, time, frequency, angle, and polarization diversity which are created using multiple antennas, frequency bands, time slots, antenna angles or polarizations.
3) A Rake receiver is used to implement path diversity, capturing multipath signal energy with fingers tuned to peaks in the delay profile and maximizing ratio combining.
This document discusses advanced wireless communication technologies and their evolution over time to meet increasing data rate demands. It covers:
1) How wireless spectrum has become crowded as usage has increased, challenging engineers to develop technologies to achieve higher data rates within limited spectrum.
2) The evolution of mobile communication standards from 1G analog to 2G digital systems like GSM, and then 3G technologies like UMTS that supported data rates up to 384kbps.
3) Emerging 4G technologies aimed to support rates over 20Mbps using techniques like MIMO, adaptive modulation, and OFDM to more efficiently use available spectrum.
This document provides an overview of key concepts in antennas and propagation. It defines an antenna as a device that transmits or receives electromagnetic waves. It describes common antenna types like dipoles and parabolic reflectors. It also covers topics like radiation patterns, antenna gain, propagation modes (ground wave, sky wave, line-of-sight), factors that affect signal strength over distance like free space loss and multipath, and techniques to mitigate noise and fading like diversity and error correction.
This document summarizes different transmission media used for communication including guided media like twisted pair, coaxial cable, and optical fiber as well as unguided wireless transmission. It discusses characteristics of each medium such as bandwidth, attenuation, delay, and repeater spacing. Key concerns for any transmission include data rate, distance, and impairments from attenuation and interference. The document also provides tables comparing specifications of different cable categories and wavelength bands for optical fiber.
This document provides an overview of radio frequency (RF) antennas, including their fundamental characteristics and types. It describes how antennas transmit and receive signals, key antenna properties like gain and beamwidth, and different antenna types and configurations. It also addresses signal coverage problems and strategies for overcoming them, as well as how to perform return loss and antenna gain measurements.
Multiple Input Multiple Output (MIMO) technology uses multiple antennas at both the transmitter and receiver to improve channel robustness and throughput. By utilizing reflected signals, MIMO can provide gains in channel robustness and throughput. MIMO was initially developed in the 1990s after additional processing power made it possible to utilize both spatial diversity and spatial multiplexing. MIMO systems provide either spatial multiplexing gain to maximize transmission rate or diversity gain to minimize errors and prioritize reliability. MIMO is now used in many wireless communication standards and ongoing research aims to develop more advanced MIMO techniques.
This presentation deals with topics such as Electromagnetic Spectrum, Wireless Propagation, Signals, Signal propagation effects, Spread spectrum and cellular systems.
Access the video from this presentation for free from
http://www.rohde-schwarz-usa.com/DebuggingEMISS_On-Demand.html
Overview:
Electromagnetic interference is increasingly becoming a problem in complex systems that must interoperate in both digital and RF domains. When failures due to EMI occur it is often difficult to track down the sources of such failures using standard test receivers and spectrum analyzers. The unique ability of real-time spectrum analysis and synchronous time domain signal acquisition to capture transient events can quickly reveals details about the sources of EMI.
What You Will Learn:
How to isolate and analyze sources of EMI using an oscilloscope
Measurement considerations for correlating time and frequency domains
Near field probing basics
Presented By:
Dave Rishavy, Product Manager Oscilloscopes, Rohde & Schwarz
Dave Rishavy has a BS in Electrical Engineering from Florida State University and an MBA from the University of Colorado. Prior to joining Rohde and Schwarz, Mr. Rishavy gained over 15 years of experience in the test and measurement field at Agilent Technologies. This included positions in a wide range of technical marketing areas such as application engineering, product marketing, marketing management and strategic product planning. While at Agilent, Dave led the marketing and industry segment teams for the Infiniium line of oscilloscopes as well as high end logic analysis.
Similar to Sect.03 - Basic technologies and concepts (m004) - 16-02-04-1.pptx (20)
TIME DIVISION MULTIPLEXING TECHNIQUE FOR COMMUNICATION SYSTEMHODECEDSIET
Time Division Multiplexing (TDM) is a method of transmitting multiple signals over a single communication channel by dividing the signal into many segments, each having a very short duration of time. These time slots are then allocated to different data streams, allowing multiple signals to share the same transmission medium efficiently. TDM is widely used in telecommunications and data communication systems.
### How TDM Works
1. **Time Slots Allocation**: The core principle of TDM is to assign distinct time slots to each signal. During each time slot, the respective signal is transmitted, and then the process repeats cyclically. For example, if there are four signals to be transmitted, the TDM cycle will divide time into four slots, each assigned to one signal.
2. **Synchronization**: Synchronization is crucial in TDM systems to ensure that the signals are correctly aligned with their respective time slots. Both the transmitter and receiver must be synchronized to avoid any overlap or loss of data. This synchronization is typically maintained by a clock signal that ensures time slots are accurately aligned.
3. **Frame Structure**: TDM data is organized into frames, where each frame consists of a set of time slots. Each frame is repeated at regular intervals, ensuring continuous transmission of data streams. The frame structure helps in managing the data streams and maintaining the synchronization between the transmitter and receiver.
4. **Multiplexer and Demultiplexer**: At the transmitting end, a multiplexer combines multiple input signals into a single composite signal by assigning each signal to a specific time slot. At the receiving end, a demultiplexer separates the composite signal back into individual signals based on their respective time slots.
### Types of TDM
1. **Synchronous TDM**: In synchronous TDM, time slots are pre-assigned to each signal, regardless of whether the signal has data to transmit or not. This can lead to inefficiencies if some time slots remain empty due to the absence of data.
2. **Asynchronous TDM (or Statistical TDM)**: Asynchronous TDM addresses the inefficiencies of synchronous TDM by allocating time slots dynamically based on the presence of data. Time slots are assigned only when there is data to transmit, which optimizes the use of the communication channel.
### Applications of TDM
- **Telecommunications**: TDM is extensively used in telecommunication systems, such as in T1 and E1 lines, where multiple telephone calls are transmitted over a single line by assigning each call to a specific time slot.
- **Digital Audio and Video Broadcasting**: TDM is used in broadcasting systems to transmit multiple audio or video streams over a single channel, ensuring efficient use of bandwidth.
- **Computer Networks**: TDM is used in network protocols and systems to manage the transmission of data from multiple sources over a single network medium.
### Advantages of TDM
- **Efficient Use of Bandwidth**: TDM all
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
Optimizing Gradle Builds - Gradle DPE Tour Berlin 2024Sinan KOZAK
Sinan from the Delivery Hero mobile infrastructure engineering team shares a deep dive into performance acceleration with Gradle build cache optimizations. Sinan shares their journey into solving complex build-cache problems that affect Gradle builds. By understanding the challenges and solutions found in our journey, we aim to demonstrate the possibilities for faster builds. The case study reveals how overlapping outputs and cache misconfigurations led to significant increases in build times, especially as the project scaled up with numerous modules using Paparazzi tests. The journey from diagnosing to defeating cache issues offers invaluable lessons on maintaining cache integrity without sacrificing functionality.
2. BASIC TECHNOLOGIES and CONCEPTS
Basic technologies and concepts
Traffic direction
Bidirectional transmission modes
Radio medium sharing modes
Antenna basics
Directivity / Gain
Radiation patterns
MIMO technologies
Diversity
Spatial multiplexing
Beam forming
OFDM vs. OFDMA
Errors handling
FEC
ARQ
H-ARQ
Operation flow
APN (Access Point Name)
AS / NAS (Access Stratum / Non-Access
Stratum)
3. BASIC TECHNOLOGIES
Traffic direction
Up link (UL)
UE to eNB
Down link (DL)
eNB to UE
Bidirectional transmission modes
HD - Half Duplex
Nodes can not transmit and receive simultaneously
A half duplex eNB can communicate only with half duplex UE
FD - Full Duplex
Nodes can transmit and receive simultaneously
A full duplex eNB can support both half duplex and full duplex UE
Radio medium sharing modes (Duplex modes)
FDD - Frequency Division Duplex
Uplink traffic occurs on one frequency, downlink traffic occurs on a different frequency
Supports both half duplex and full duplex operation of nodes
Efficient for symmetric traffic (similar data amounts in UL and DL)
TDD - Time Division Duplex
Uplink traffic and downlink traffic occur on same frequency
Supports only half duplex operation of nodes
Efficient for asymmetric traffic (e.g. DL data amount significantly greater than UL data amount)
SAE GW
eNB
eNB
Uu
S11
S5/S8
Uu
S6a
Gxc
Gx/S7
Rx
X2
MME
S10
E-UTRAN Evolved Packet Core (EPC)
UE
UE
PCRF
HSS
S
GW
PDN /
IMS
SGi
P
GW
UL
DL
R
4. BASIC TECHNOLOGIES
Antennas basics
Definitions
Generator
l[m] = wavelength =
f = 2.4 GHz l = 12.5 cm
f = 700 MHz l = 43 cm
Transmission line
The device used to guide RF energy from one point to another one, with minimum
attenuation, heat and radiation losses
Guides the energy
Radio antenna
The structure associated with the region of transition between a guided wave and a free
space wave, or vice versa
Radiates/receives energy
Transmission line
(spacing between
wires is only a fraction
of the wave length)
Antenna
(separation between
wires is in the range
of one or more wave
lengths)
c [3*108m/s]
f [Hz]
5. BASIC TECHNOLOGIES
Antennas basics
Directivity / Gain
The energy fed into the antenna is radiated
in the whole space.
A receiver RCV, located in the far field of the
transmitter, gets the basic element of energy
generated by the presence of 17dBm (50mW)
in the whole space.
The energy fed into the antenna is radiated
only in part of the space.
A receiver RCV, located in the far field of the
transmitter, gets the basic element of energy
generated by the presence of 17dBm (50mW)
in the defined volume, which is equivalent
with the presence of much more energy
isotropically distributed.
Isotropic antenna (theoretical)
Non-isotropic antenna (real)
Generator
17dBm (50mW)
Generator
17dBm (50mW)
RCV
RCV
6. BASIC TECHNOLOGIES
Antennas basics
Directivity / Gain
For same amount of energy fed into the
antenna, a non-isotropic antenna will
transmit its signal over longer distances.
Non-isotropic antennas are characterized by
their capability to focus the transmitted
energy, expressed by the antenna gain
An antenna with 3dBi gain, radiates its
energy into 50% of the space
A 3dBi antenna fed with 17dBm (50mW)
behaves (in its active field) as an isotropic
antenna fed with 20dBm (100mW)
Even if, in fact, the antenna radiates only
17 dBm (50mW), it is said that it radiates
20 dBm (100mW) EIRP (Equivalent
Isotropically Radiated Power)
Antenna gain = [dBi]
volume (radiation) of subject antenna
volume (radiation) of isotropic antenna
Non-isotropic antenna (real)
Non-isotropic antenna (real)
Generator
17dBm (50mW)
RCV
Generator
17dBm (50mW)
RCV
Powerinput [dBm] + Gain [dBi] = Poweroutput [dBm EIRP]
14. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies (MIMO - Multiple Input, Multiple Output)
MIMO - Multiple Input Multiple Output
Generic name relating to technologies using multiple antennas for
transmission / reception
The name relates to the transmission channel (into which multiple
signals (from multiple antennas) are injected, while delivering multiple
output signals (toward multiple receiving antennas)
Differentiation of signals generated by different antennas is achieved
via signals' orthogonality obtained via:
antennas space diversity (antennas mechanically separated by a
few λ (signal wavelength) (could be done in BS but can not be done in UEs
which have small form factor ... ), or
antennas space polarization
The antennas can handle SAME or DIFFERENT data streams (layers)
Multi-antenna mode
Number of simultaneously transmitted data streams
over multiple antennas (= number of layers)
(same frequencies, same time, different polarization)
Gain
Diversity
Tx
one layer
Higher gain (greater distance
and/or higher modulation order)
Rx
Spatial multiplexing
SU-MIMO
multiple layers
User throughput:
increased
MU-MIMO
Aggregate throughput:
increased
Beam forming one / multiple layer(s) Distance, Capacity
SU - Single User
MU - Multi User
MIMO - Multiple In, Multiple Out
Maximum values - up to rel.10
eNB
antennas
Data
streams
(layers)
UE
antennas
DL 4 (Tx) 2 2 (Rx)
UL 4 (Rx) 1 1 (Tx)
Maximum values - rel.10
eNB
antennas
Data
streams
(layers)
UE
antennas
DL 8 (Tx) 8 8 (Rx)
UL 8 (Rx) 4 4 (Tx)
2
1
8
4
15. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Diversity
Scope - reducing the amount of fading by combining - at receiver - multiple copies of same signal
The multiple copies of same signal have to encounter different fading over the channel, i.e. the
different propagation channels have to have low mutual correlation
Nt - nr of Tx ant.
Nr - nr of Rx ant.
Tx entity
T1
Rx entity
R1
Nt Nr
mode
data streams
(same freq, same time)
Diversity one
Spatial muxing multiple
Beam forming one / multiple
4 x 1 1 x 4 4 x 4
Rx entity
R1
Tx entity Nt Nr
T1
Tx entity Rx entity
Nt Nr
T1 R1
16. Tx entity Rx entity
Nt Nr
T1 R1
BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Diversity
Rx entity
R1
Tx entity
T1
Tx entity
T1
Rx entity
R1
Transmit diversity
Same signal transmitted on multiple antennas
Gain: 10log(Nt) (e.g. for 2 Tx antennas => 3dB gain)
Increase in gain can be used for:
Distance increase and / or
Throughput increase (higher modulation order)
Risk of destructive interference at the receiving antenna; solution to avoid it:
Alamouti technique; defined for two antennas and two subcarriers only
antenna#1 transmits symbol#1 and symbol#2 on different sub-carriers
antenna#2 transmits phase modified versions of symbol#1 and symbol#2 on
different sub-carriers
the receiver is not involved in the decision (logical open loop operation)
Nt Nr
Nt - nr of Tx ant.
Nr - nr of Rx ant.
Nt Nr
mode
data streams
(same freq, same time)
Diversity one
Spatial muxing multiple
Beam forming one / multiple
One layer
(one block/stream)(blue)
4 antennas
4 x 1 MISO
MISO - Multiple
Input Single Output
1 x 4 SIMO 4 x 4 MIMO
17. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Diversity
Rx entity
R1
Tx entity
T1
Tx entity
T1
Rx entity
R1
Receive diversity
Same signal received on multiple antennas
Gain: 10log(Nr) (e.g. for 2 Rx antennas => 3dB gain)
Increase in gain can be used for:
Distance increase and / or
Throughput increase (higher modulation order)
Transmit and Receive diversity
Same signal transmitted on multiple antennas and received on multiple antennas
(Nt and Nr could have different values)
Gain: 10log(Nt) + 10log(Nr)
Increase in gain can be used for:
Distance increase and / or
Throughput increase (higher modulation order)
Nt Nr
Nt - nr of Tx ant.
Nr - nr of Rx ant.
Nt Nr
mode
data streams
(same freq, same time)
Diversity one
Spatial muxing multiple
Beam forming one / multiple
1 x 4 SIMO 4 x 4 MIMO
Tx entity Rx entity
Nt Nr
T1 R1
4 x 1 MISO
MISO - Multiple
Input Single Output
SIMO - Single INput
Multiple Output
18. Nt = 2; Nr = 2; Nr of layers, RI= 2
BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Spatial multiplexing (a.k.a. multi-layer transmission, MIMO)
Nt - nr of Tx ant.
Nr - nr of Rx ant.
Tx entity
T1
Nt Nr
T2
Rx entity
R1
R2
Single User spatial multiplexing (SU-MIMO)
Multiple different streams
(multiple layers, Rank Indicator - RI = nrs) over multiple antennas
(same frequencies, same time, different antennas with different polarization)
Aggregate capacity: Capacitysingle-stream * RI
Gain per stream: 10log(Nt-stream) + 10log(Nr-stream)
Increase in gain can be used for:
Distance increase and / or
Throughput increase (higher modulation order, per stream)
Correct recovery occurs if the signals received at the two antennas
are different (not good in clear Line Of Sight - LOS)
UE
eNB
mode
data streams
(same freq, same time)
Diversity one
Spatial muxing multiple
Beam forming one / multiple
Requires calibration, to calculate channel influence on
each transmitter to receiver path; executed via a priori
known Reference Signals transmitted periodically by eNB
During calibration
Known elements: T1, T2, R1, R2
Calculated elements: x11, x12, x21, x22
During operation
Known elements: R1, R2, x11, x12, x21, x22
Calculated elements: T1, T2
R1 = x11*T1 + x21*T2
R2 = x12*T1 + x22*T2
Channel
T1
T2
R1
R2
x11
x12
x21
x22
Tx entity
T1
Nt Nr
T2
Rx entity
R1
R2
UE
eNB
RI - Rank Indicator
nrs - nr of streams
Nt-stream = 2; Nr = 2; Nr of layers, RI= 2
19. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Spatial multiplexing (a.k.a. multi-layer transmission, MIMO)
Nt - nr of Tx ant.
Nr - nr of Rx ant.
Tx entity
T1
Nt Nr
T2
Rx entity
R1
R2
Single User spatial multiplexing (SU-MIMO)
If the signals received at the antennas are not different enough for decoding, then:
Open loop operation
UE may ask eNB to switch to diversity mode, i.e. to transmit one single stream over
multiple antennas (instead of two streams on multiple antennas) => lower capacity, higher
resilience
UE request is done by indicating desired RI - Rank Indicator (number of layers, number of
simultaneous streams that Rx-er can receive)
RI = 2 - Spatial Multiplexing (high capacity)
RI = 1 - Diversity (high resilience)
UE
eNB
mode
data streams
(same freq, same time)
Diversity one
Spatial muxing multiple
Beam forming one / multiple
Requires calibration, to calculate channel influence on
each transmitter to receiver path; executed via a priori
known Reference Signals transmitted periodically by eNB
During calibration
Known elements: T1, T2, R1, R2
Calculated elements: x11, x12, x21, x22
During operation
Known elements: R1, R2, x11, x12, x21, x22
Calculated elements: T1, T2
R1 = x11*T1 + x21*T2
R2 = x12*T1 + x22*T2
Channel
T1
T2
R1
R2
x11
x12
x21
x22
RI - Rank Indicator
20. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Spatial multiplexing (a.k.a. multi-layer transmission, MIMO)
Nt - nr of Tx ant.
Nr - nr of Rx ant.
Tx entity
T1
Nt Nr
T2
Rx entity
R1
R2
Single User spatial multiplexing (SU-MIMO)
If the signals received at the antennas are not different enough for decoding, then:
Closed loop operation
UE sends to eNB the desired RI
UE sends to eNB the desired Precoding Matrix Indicator (PMI) to be used by eNB (phase,
amplitude modifications so that the signals will arrive correctly at UE) to minimize the
effect of fading
Fading is function of frequency, so PMI is function of frequency... UE may report PMIs for
different frequencies, helping BS to select the right frequencies for transmission
(OFDMA!)
Closed loop needs time => not good for fast moving UEs, where the conditions change
fast and the reporting mechanism brings to transmitter information that is not relevant
anymore...
UE
eNB
mode
data streams
(same freq, same time)
Diversity one
Spatial muxing multiple
Beam forming one / multiple
Requires calibration, to calculate channel influence on
each transmitter to receiver path; executed via a priori
known Reference Signals transmitted periodically by eNB
During calibration
Known elements: T1, T2, R1, R2
Calculated elements: x11, x12, x21, x22
During operation
Known elements: R1, R2, x11, x12, x21, x22
Calculated elements: T1, T2
R1 = x11*T1 + x21*T2
R2 = x12*T1 + x22*T2
Channel
T1
T2
R1
R2
x11
x12
x21
x22
RI - Rank Indicator
PMI- Precoding
Matrix Indicator
UE - User Equip.
BS - Base Station
21. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Transmission modes (LTE) - Down Link (DL)
Transmission Modes (TM) - DL TS 36.213
TM 1
Single transmit
antenna
SISO or SIMO
TM 2
Transmit
diversity
Transmit diversity - One stream over multiple antennas
Used as fall back option, when spatial multiplexing (multiple streams over multiple
antennas) cannot be used
TM 3
Open loop
spatial
multiplexing
with CDD
Spatial multiplexing - Multiple streams over multiple antennas
All streams to same UE
Open loop - UE does not request from eNB specific transmission parameters for
efficient reception (as function of radio channel conditions)
Used when no channel info is available, or when channel parameters are changing very
fast (e.g. UE high speed movement)
To increase frequency diversity, the signals are presented to different antennas with
different delays (CDD) (equivalent to phase modification in frequency domain)
TM 4
Closed loop
spatial
multiplexing
Spatial multiplexing - Multiple streams over multiple antennas
All streams to same UE
Closed loop - UE requests from eNB specific transmission parameters for efficient
reception (as function of radio channel conditions)
The request uses an index referring to a table listing precoding matrixes (Precoding
Matrix Index - PMI)
The table lists precoding for both the case of one stream and the case of two streams
Fall back to transmit diversity
CDD - Cyclic Delay Diversity
PMI - Precoding Matrix Index
RI - Rank Indicator
SU-MIMO - Single User MIMO
MU-MIMO - Multi User MIMO
CoMP - Coordinated Multi-Point
SISO - Single In Single Out
SIMO - Single In Multiple Out
22. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Transmission modes (LTE) - Down Link (DL)
CDD - Cyclic Delay Diversity
PMI - Precoding Matrix Index
RI - Rank Indicator
SU-MIMO - Single User MIMO
MU-MIMO - Multi User MIMO
CoMP - Coordinated Multi-Point
SISO - Single In Single Out
SIMO - Single In Multiple Out
23. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Transmission modes (LTE) - Down Link (DL)
CDD - Cyclic Delay Diversity
PMI - Precoding Matrix Index
RI - Rank Indicator
SU-MIMO - Single User MIMO
MU-MIMO - Multi User MIMO
CoMP - Coordinated Multi-Point
Transmission modes (TM) - DL MIMO type
Nr of
streams
Nr of
antennas
Streams direction
UE request for
precoding (loop)
TM 1 Single transmit antenna - 1 1 to single UE -
TM 2 Transmit diversity Diversity 1 up to 8 to single UE -
TM 3
Open loop spatial
multiplexing (SU-MIMO)
Spatial mux 2 or 4 2 or 4 all to same UE no
TM 4
Closed loop spatial
multiplexing (SU-MIMO)
Spatial mux 2 or 4 2 or 4 all to same UE yes
TM 5
Multi-user MIMO (MU-
MIMO)
Spatial mux 2 or 4 2 or 4 one stream per UE yes
TM 6
Closed loop spatial
multiplexing with RI=1
Spatial mux 1 2 or 4 to single UE yes
TM 7 One layer beamforming Beamforming 1 2 or 4 to single UE -
TM 8 Dual layer beamforming Beamforming 2 2 or 4
all to same UE (SU-MIMO) -
one per UE (MU-MIMO) -
TM 9 8 layer transmission Spatial mux up to 8 up to 8
all to same UE (SU-MIMO) -
one per UE (MU-MIMO) -
TM 10
Support for CoMP
(Coordinated Multi-Point)
- - - - -
24. BASIC TECHNOLOGIES
Antennas basics
Multiple antennas technologies
Transmission modes (LTE) - Up Link (UL)
CDD - Cyclic Delay Diversity
PMI - Precoding Matrix Index
RI - Rank Indicator
SU-MIMO - Single User MIMO
MU-MIMO - Multi User MIMO
CoMP - Coordinated Multi-Point
Transmission Modes (TM) - UL TS 36.213
TM 1
Single transmit
antenna
-
TM 2
(Rel.10)
Closed loop
spatial
multiplexing
Spatial multiplexing - Multiple streams over multiple antennas
Closed loop - eNB requests from UE specific transmission parameters for efficient
reception (as function of radio channel conditions)
The request uses an index referring to a table listing precoding matrixes (Precoding
Matrix Index - PMI)
25. BASIC TECHNOLOGIES
OFDM vs. OFDMA
f
user G
traffic
user R
traffic
user B
traffic
user P
traffic
t
t
f
user V
traffic
OFDM - Orthogonal Frequency Division Multiplexing
Radio technology carrying traffic over multiple sub-carriers simultaneously
OFDMA - Orthogonal Frequency Division Multiple Access
Multiple stations access method, allowing stations to transmit/receive using OFDM over limited
amount of frequencies and for limited time
OFDM OFDM sub-channelization OFDMA
Frequency
allocation
per user
all sub-carriers some sub-carriers some sub-carriers
Time
allocation
per user
all the time all the time limited time
f
user R
traffic
user B
traffic
t
user V
traffic
user G
traffic
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
OFDM - Orthogonal Frequency
Division Multiplexing
OFDMA - Orthogonal Frequency
Division Multiple Access
26. BASIC TECHNOLOGIES
OFDM vs. OFDMA
In LTE OFDMA
Frequency axis has granularity of groups of 12 sub-carriers
Time axis has granularity of 0.5 ms
The block of 12 sub-carriers * 0.5ms is known as a Resource Block (RB)
1 RB = 12 sub-carriers * 0.5ms
Resource allocation in LTE OFDMA is executed
with the granularity of
12 subcarriers in frequency domain (1 RB)
1 ms in time domain (1 sub-frame, 1 RB pair)
f
user R
traffic
user B
traffic
t
user V
traffic
user G
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
1ms
0.5ms
1
RB
1
RB pair
OFDM - Orthogonal Frequency
Division Multiplexing
OFDMA - Orthogonal Frequency
Division Multiple Access
RB - Resource Block
27. BASIC TECHNOLOGIES
Channel / carrier / band / site / sector / multicarrier
Channel
A group of RBs (frequencies) allocated to operator (used by eNB) for radio communication
For data transfer to/from users, eNB can allocate to each UE from 1 to all RBs, depending on
the amount of data to be transferred
f
user R
traffic
user B
traffic
t
user V
traffic
user G
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
1ms
0.5ms
LTE channel
widths
Nr. of
RBs
Channel
width
[MHz]
6 1.4
15 3
25 5
50 10
75 15
100 20
Channel
(6 RBs, 1.4 MHz)
Carrier
The frequency around which a channel is located (i.e. the central frequency of a channel)
Carrier
(2.340 GHz)
29. Band
40
(2.3
GHz
-
2.4
GHz)
BASIC TECHNOLOGIES
Channel / carrier / band / site / sector / multicarrier
Site
Geographical location of a tower
f
1ms
0.5ms
user R
traffic
user B
traffic
user V
traffic
user G
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
Channel
Carrier
2.3 GHz
2.4 GHz
Site
Sector
Geometry entity / direction
Cell
The radio entity covering a sector
Each cell uses one carrier / channel
(except the case of carrier aggregation)
Sector
Sector
30. Band
40
(2.3
GHz
-
2.4
GHz)
BASIC TECHNOLOGIES
Channel / carrier / band / site / sector / multicarrier
f
1ms
0.5ms
user R
traffic
user B
traffic
user V
traffic
user G
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
Channel
2.3 GHz
2.4 GHz
Site
Multicarrier systems
Systems able to use multiple carriers
Adjacency
contiguous
non-contiguous
Bands
same
different
Timing
At different moments in time
(e.g. UE adapting itself to its serving eNB)
Sector
Sector
Simultaneously
Multi sector eNB, each sector using a different carrier (one device equivalent to multiple devices)
Single sector using multi-carrier aggregation; equivalent to a wider channel. Aggregate
capacity is same as the sum of the components; However, with carrier aggregation, a UE
can get the WHOLE aggregate channel width resulting in higher throughput per UE.
Carrier
31. BASIC TECHNOLOGIES
Radio frame structure - Type 1: FDD
FDD division entities
frame - 10 ms
subframe - 1 ms
slot - 0.5 ms
Two identical structures are present
on different frequencies, for each direction (UL, DL)
frame 10 ms
subframe
# 1
1 ms
subframe
# 2
1 ms
subframe
# 3
1 ms
subframe
# 4
1 ms
subframe
# 5
1 ms
subframe
# 6
1 ms
subframe
# 7
1 ms
subframe
# 8
1 ms
subframe
# 9
1 ms
subframe
# 10
1 ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
frame 10 ms .
me subframe
# 8
1 ms
subframe
# 9
1 ms
subframe
# 10
1 ms
ot
5
s
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
3 14 15 16 17 18 19
frame 10 ms
subframe
# 1
1 ms
subfram
# 2
1 ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slo
0.5
m
0 1 2 3
f
user R
traffic
user B
traffic
t
user V
traffic
user G
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
1ms
0.5ms
frame 10 ms
subframe
# 1
1 ms
subframe
# 2
1 ms
subframe
# 3
1 ms
subframe
# 4
1 ms
subframe
# 5
1 ms
subframe
# 6
1 ms
subframe
# 7
1 ms
subframe
# 8
1 ms
subframe
# 9
1 ms
subframe
# 10
1 ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
frame 10 ms .
me subframe
# 8
1 ms
subframe
# 9
1 ms
subframe
# 10
1 ms
ot
5
s
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
3 14 15 16 17 18 19
frame 10 ms
subframe
# 1
1 ms
subfram
# 2
1 ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slo
0.5
m
0 1 2 3
32. frame 10 ms
subfr. # 1
1 ms
subfr. # 2
1 ms
subfr. # 3
1 ms
subfr. # 4
1 ms
subfr. # 5
1 ms
subfr. # 6
1 ms
subfr. # 7
1 ms
subfr. # 8
1 ms
subfr. # 9
1 ms
subfr. #10
1 ms
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
frame 10 ms .
me subframe
# 8
1 ms
subframe
# 9
1 ms
subframe
# 10
1 ms
ot
5
s
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
3 14 15 16 17 18 19
frame 10 ms .
me subframe
# 8
1 ms
subframe
# 9
1 ms
subframe
# 10
1 ms
ot
5
s
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
slot
0.5
ms
3 14 15 16 17 18 19
frame 10 ms
subfr. # 1
1 ms 1 ms
0 1 2 3
f
user R
traffic
t
user V
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user P
traffic
user B
traffic
1ms
0.5ms
user B
traffic
user V
traffic
user G
traffic
user P
traffic
user G
traffic
user O
traffic
f
user R
traffic
user B
traffic
t
user V
traffic
user G
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
1ms
0.5ms
frame 10 ms
subfr. # 1
1 ms
subfr. # 2
1 ms
subfr. # 3
1 ms
subfr. # 4
1 ms
subfr. # 5
1 ms
subfr. # 6
1 ms
subfr. # 7
1 ms
subfr. # 8
1 ms
subfr. # 9
1 ms
subfr. #10
1 ms
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
frame 10 ms
subfr. # 1
1 ms 1 ms
0 1 2 3
BASIC TECHNOLOGIES
Radio frame structure - Type 1: FDD
f
UL
DL
Two identical structures are present
on different frequencies, for each direction (UL, DL)
33. BASIC TECHNOLOGIES
Radio frame structure - Type 2: TDD
TDD division entities
frame - 10 ms
half frame - 5 ms
subframe - 1 ms
standard
special
dwPTS - DL Pilot Time Slot
GP - Guard Period
upPTS - UL Pilot Time Slot
slot - 0.5 ms
One single structure is present allowing UL and DL
traffic to share one single frequency (half duplex)
The amount of subframes allocated to each
direction can be dynamically changed by eNB,
based on load conditions
frame 10 ms
half frame 0 half frame 1
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
frame 10 ms
half frame 1
me subframe
1 ms
subframe
1 ms
subframe
1 ms
ot slot slot slot slot slot slot
14 15 16 17 18 19
frame 10 ms
subframe
1 ms
subfram
1 ms
slot slot slot slo
0 1 1
Frame structure TDD (format for DL + UL, on same frequency)
dwPTS - DL Pilot Time Slot
upPTS - UL Pilot Time Slot
GP- Guard Period
f
user R
traffic
user B
traffic
t
user V
traffic
user G
traffic
RB #4 = 12 freq
RB #5 = 12 freq
RB #3 = 12 freq
RB #2 = 12 freq
RB #1 = 12 freq
RB #0 = 12 freq
user O
traffic
user B
traffic
user O
traffic
user P
traffic
user V
traffic
user B
traffic
1ms
0.5ms
34. UL / DL allocation configurations
0
1
2
3
4
5
6
BASIC TECHNOLOGIES
Radio frame structure - Type 2: TDD
D S U D D D S U D D
D S U U U D D D D D
D S U U D D D D D D
D S U D D D D D D D
D S U U U D S U U D
D S U U D D S U U D
D S U U U D S U U U
dwPTS Guard Period upPTS
dwPTS - DL Pilot Time Slot - synchro and
user data + DL Control ch (scheduling and
control info)
GP - Guard Period
upPTS - UL Pilot Time Slot - for transmission
of PRA.CH and Sounding Ref Signal SRS
TS 36.211
frame 10 ms
half frame 0 half frame 1
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
subframe
1 ms
slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot slot
0 1 2 3 4 5 6 7 8 9
frame 10 ms
half frame 1
me subframe
1 ms
subframe
1 ms
subframe
1 ms
ot slot slot slot slot slot slot
7 8 9
frame 10 ms
subframe
1 ms
subfram
1 ms
slot slot slot slo
0 1
The amount of subframes allocated to each
direction can be dynamically changed by eNB,
based on load conditions
7 UL/DL allocation configurations are defined
dwPTS - DL Pilot Time Slot
upPTS - UL Pilot Time Slot
GP- Guard Period
U / D - UL / DL subframe
S - Special subframe
35. BASIC TECHNOLOGIES
Errors handling
Errors over the air link are detected / corrected using:
Forward Error Correction (FEC)
Automatic Repeat Request (ARQ)
Hybrid ARQ (H-ARQ)
Errors handling
FEC
ARQ
H-ARQ
36. BASIC TECHNOLOGIES
Errors handling
Forward Error Correction (FEC)
For error detection and correction
purposes, FEC transmits instead
of the original data bits, a bigger
quantity of OTHER bits
Coding rate = amount of data bits / total amount of bits transmitted
actual bits transmitted (different and more than the original data)
Errors handling
FEC
ARQ
H-ARQ
Two major FEC techniques are used in LTE:
Convolutional encoding (at transmission) with Viterbi decoding (at reception)
Used for control channels
Turbo convolutional encoding
Used for data channels
Coding
rate value
Efficiency
Error
protection
level
High High Low
Low Low High
data bits (info to be transmitted)
actual bits transmitted (different and more than the original data)
data bits (info to be transmitted)
37. BASIC TECHNOLOGIES
Errors handling
Forward Error Correction (FEC)
Convolutional Encoding / Viterbi Decoding (for control channels)
Basic coding rate is 1/3
In order to improve coding
efficiency, some of the A, B, C
bits may be omitted while
transmitting (puncturing), and
reinserted as “dummy” bits at
reception (rate matching)
If more bandwidth is available,
some of the bits could be
repeated (rate matching)
Convolutional
Encoder
Ai
Bi
Ci
xi
data
IN
encoded
data
Convolutional
Encoder
data
IN
data
OUT
channel
Convolutional Coding
encoded
data
+
errors
xi
Ai
Bi
Ci
encoded
data
Viterbi
decoder
Convolutional Encoding
Generator vector {1011011 (A); 1111001 (B); 1110101 (C)}
T
1
T
2
T
3
T
4
T
5
T
6
0
1
1
1
1
1
1
1
1
1
1
0
0
0
1
1
0
0
1
1
1
xi
data
IN
Ai
Bi
Ci
encoded
data
Errors handling
FEC
ARQ
H-ARQ
38. BASIC TECHNOLOGIES
Errors handling
Forward Error Correction (FEC)
Turbo convolutional encoding (for data channels)
Turbo Convolutional Encoding
Ai
Bi
Ci
e
n
c
o
d
e
d
d
a
t
a
T T
T T
xi
data
IN
T
T
Turbo code
interleaver
Turbo code - high performance FEC
mechanism
Parallel concatenation of two
convolutional encoders operating on
the original bits and on
a permutation of the original bits
executed by an interleaver
Basic coding rate is 1/3
In order to improve coding efficiency,
some of the A, B, C bits may be omitted
while transmitting (puncturing)(rate
matching)
If more bandwidth is available, some of
the bits could be repeated (rate matching)
Turbo
Encoder
data
IN
data
OUT
channel
Convolutional Coding
encoded
data
+
errors
xi
Ai
Bi
Ci
encoded
data
Decoder
Errors handling
FEC
ARQ
H-ARQ
39. BASIC TECHNOLOGIES
Errors handling
Automatic Repeat Request (ARQ)
Three ARQ types are defined:
• Stop and Wait (Sliding window = 0)
• Go Back N
• Selective Repeat
Stop and Wait (Sliding Window = 0)
- Every transmitted block has to be acknowledged by receiver
- Absence of ACK within a specified timeout forces the transmitter to re-transmit the
un-acknowledged block
1
t
1
t
2
2
ACK 1 ACK 2
3
3
lack of
ACK 3
3
3
ACK 3
XMT
RCV
Errors handling
FEC
ARQ
H-ARQ
40. BASIC TECHNOLOGIES
Errors handling
Automatic Repeat Request (ARQ)
Three ARQ types are defined:
• Stop and Wait (Sliding window = 0)
• Go Back N
• Selective Repeat
Go Back N (Sliding Window 0)
- Multiple blocks (up to a maximum “window”) are transmitted before receiving ACK
- When a specific block is un-acknowledged, transmitter re-transmits the un-acknowledged
block and ALL the following blocks
1
t
1
t
2
2
3 4
3
XMT
RCV
5 6 7 4
4
NAK
4
5 6 7 4
5 6 7
5 6 7
Errors handling
FEC
ARQ
H-ARQ
LTE window in TS 36.322: 512
41. BASIC TECHNOLOGIES
Errors handling
Automatic Repeat Request (ARQ)
Three ARQ types are defined:
• Stop and Wait (Sliding window = 0)
• Go Back N
• Selective Repeat
Selective Repeat (Sliding Window 0)
- Multiple blocks (up to a maximum “window”) are transmitted before receiving ACK
- When a specific block is un-acknowledged, transmitter re-transmits the un-acknowledged
block
1
t
1
t
2
2
3 4
3
XMT
RCV
5 6 7 4
4 5 6 7 4
8 9 10
8 9 10
Errors handling
FEC
ARQ
H-ARQ
LTE window in TS 36.322: 512
NAK
4
42. Conventional ARQ discards blocks received with errors. H-ARQ keeps them.
Multiple copies of same block are transmitted until receiver has enough cumulated information to
decode the block (time diversity).
Useful for remote located stations that never have the chance of getting/transmitting one single
copy with enough energy
Hybrid = joint operation of MAC and PHY
At reception:
Multiple H-ARQ processes in parallel, trying to recover several outstanding blocks
BASIC TECHNOLOGIES
Errors handling
Hybrid ARQ (H-ARQ)
1
t
1
t
2
2
ACK 1 NACK 2
2
2
NACK 2
2
2
ACK 2
XMT
RCV 2
2
3
total: 2
Errors handling
FEC
ARQ
H-ARQ
PHY performs retention and recombination
MAC performs signalling (ACK/NACK as result of CRC check result)
Equivalent to decision based
on majority value for each bit
43. BASIC TECHNOLOGIES
Errors handling
Hybrid ARQ (H-ARQ)
Errors handling
FEC
ARQ
H-ARQ
LTE DL traffic handling via H-ARQ
Sending ACK / NACK toward eNB - 4 sub-frames after reception of data block
Resending (toward UE) blocks that have been NACK-ed by UE
Asynchronous mode - retransmission can occur at any time (min 8ms). Requires signaling from eNB.
Adaptive mode - Each retransmission is executed using a lower modulation level
t
eNB
Transmission in
sub-frame #n
NACK 1 in
sub-frame #n+4
Retransmission in
sub-frame #(n+4)+4 or later
4 sub-frames
(4 ms)
Synchronous
Asynchronous
t
NACK 1
UE
1
1 NACK 1
4 sub-frames
(4 ms) or more
LTE UL traffic handling via H-ARQ
Sending ACK / NACK toward UE - 4 sub-frames after reception of data block
Resending (toward eNB) blocks that have been NACK-ed by eNB
Synchronous mode - retransmission occurs 4 sub-frames (predefined time) after NACK reception
Adaptive or non-adaptive mode - modulation and coding can change or not (as decided by eNB)
t
t
1 NACK
eNB
Transmission in
sub-frame #n
NACK 1 in
sub-frame #n+4
Retransmission in
Sub-frame #(n+4)+4
1
Synchronous
NACK 1
UE 1
4 sub-frames
(4 ms)
Synchronous
4 sub-frames
(4 ms)
44. BASIC TECHNOLOGIES
Errors handling
Operation flow
Errors handling
FEC
ARQ
H-ARQ
H-ARQ ACK H-ARQ NACK
drop after n retransmissions
(e.g. 1 tx + 3 re-tx)
correct incorrect
no
ACK
FEC
processing
incoming
signal
H-ARQ
processing
ARQ processing
no packet
forwarded to
ARQ process
correct packet
forwarded to
ARQ process
ACK
CRC
If H-ARQ is unsuccessful,
upper layer does not receive
the content of the respective
block
Upper layer detects missing
data => activates ARQ (ARQ
applies to part of the block
protected by H-ARQ)
45. BASIC TECHNOLOGIES
Flow / Service / Bearer
Flows and bearers are unidirectional entities
For correct operation one entity should be present for each direction
The diagrams in the slides show only one direction
To remind the reader about the fact that only one single direction is represented, arrows are used
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
R
Glossary AS - Application Server
HQ - Head Quarter
46. BASIC TECHNOLOGIES
Flow / Service / Bearer
Flow
Actual traffic (packets) generated by user (uni-directional entity)
Packets that have to be handled by the network in the same way (delay, errors, etc.) are grouped
in "flows"
Characterized by
End points
QoS (all packets that are part of same flow should get same network treatment, so that they
would experience same delay, same errors rate)
Packets type (combination of data, voice, video)
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
Voice
flow
Video
flow
Data
flow
HQ
QoS - Quality of Service
AS - Application Server
HQ - Head Quarter
R
Glossary
47. BASIC TECHNOLOGIES
Flow / Service / Bearer
Service
The activity executed by user, while using the network for traffic transport purposes
The scope of generating and transmitting the packets over the network
A service is composed of one or more "flows" per direction
Service Number of flows per direction Type of packets in the flows
e-mail 1 data
file transfer 1 data
video conference 2 (3) voice; video (data)
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
Internet surf service
Video conf service
Data
flow
Voice
flow
Video
flow
R
Glossary AS - Application Server
HQ - Head Quarter
48. BASIC TECHNOLOGIES
Flow / Service / Bearer
Service
Characterized by
End points
Type of packets present in the constituent flows
Relationship among constituent flows (e.g. in video conference service, voice packets and video packets
are generated simultaneously and should be played simultaneously)
The service is a concept valid outside the network, while in the network the service is represented
by independent packets / flows to be transported by the network under specific QoS terms
QoS - Quality of Service
AS - Application Server
HQ - Head Quarter
Glossary
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
Internet surf service
Video conf service
Data
flow
Voice
flow
Video
flow
R
49. BASIC TECHNOLOGIES
Flow / Service / Bearer
Service
A user may activate multiple services in the same time, e.g.
Service #1 : surfing the Internet
End points: UE , Internet
Flow / Packets: data
Service #2 : video conference
End points: UE, Company HQ
Flows / Packets: voice, video
Glossary
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
Internet surf service
Video conf service
Data
flow
Voice
flow
Video
flow
R
AS - Application Server
HQ - Head Quarter
50. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
Merriam-Webster: "A person who bears or carries something"
(for somebody else)
e.g. armour-bearer, bow-bearer
... traffic bearer (porter, transporter)
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
EPS - Evolved Packet System
AS - Application Server
HQ - Head Quarter
R
to AS
Glossary
51. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
For the purpose of transporting / carrying user's packets (flows) through the network, an
encapsulation service (uni-directional) is created, known as a "bearer"
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
EPS - Evolved Packet System
AS - Application Server
HQ - Head Quarter
R
to AS
Glossary
52. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
Characterized by
End points
QoS
Path in the network
Capsule structure
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
EPS - Evolved Packet System
AS - Application Server
HQ - Head Quarter
R
Glossary
LTE bearer is characterized by
End points
QoS
Path in the network
Capsule structure
53. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
Characterized by
End points
Same end points as those of the flow it carries
e.g. EPS bearer end points: UE / P-GW
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
EPS - Evolved Packet System
AS - Application Server
HQ - Head Quarter
R
Glossary
LTE bearer is characterized by
End points
QoS
Path in the network
Capsule structure
54. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
Characterized by
QoS offered to the capsules carrying user data packets / flows
In LTE, all packets in a bearer get same treatment resulting in the packets experiencing
basically same delay, same error rate
Flows requiring different QoS, use different EPS bearers, e.g. in video conf.:
Voice flow expected QoS: low delay, can live with error rate; constant bit rate
Data flow expected QoS: low error rate, can live with delays; variable bit rate
Video flow expected QoS: low delay, low error rate; constant or variable bit rate
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
EPS - Evolved Packet System
QCI - Quality Class ID
AS - Application Server
HQ - Head Quarter
R
Glossary
LTE bearer is characterized by
End points
QoS
Path in the network
Capsule structure
55. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
Characterized by
QoS offered to the capsules carrying user data packets / flows
GBR - Guaranteed Bit Rate (minimum committed / expected long term throughput average)
(suitable for real time signals (voice, video)) (Also has MBR - Maximum allowed Bit Rate)
non-GBR - (good enough for non real time applications (file transfer, internet access))
Aggregate Max Bit Rate allowed per UE, for all UE's non-GBR bearers (UE-AMBR)
Aggregate Max Bit Rate per P-GW, for all non-GBR bearers reaching a P-GW (APN-AMBR)
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
EPS - Evolved Packet System
GBR - Guaranteed Bit Rate
AMBR - Aggregate Max Bit Rate
APN - Access Point Name
AS - Application Server
HQ - Head Quarter
R
Glossary
LTE bearer is characterized by
End points
QoS
Path in the network
Capsule structure
56. BASIC TECHNOLOGIES
Flow / Service / Bearer
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
QCI GBR type Priority
Delay
(ms)
Packet
error
rate
Typical usage
1 GBR 2 100 10-2 Conversational voice
2 GBR 4 150 10-3 Conversational video (live streaming)
3 GBR 3 50 10-3 Real time gaming
4 GBR 5 300 10-6 Video (buffered streaming)
5 Non-GBR
1
(highest)
100 10-6 IMS signaling
6 Non-GBR 6 300 10-6 Video (buffered streaming)
7 Non-GBR 7 100 10-3 Voice, Video (live streaming)
8 Non-GBR 8 300 10-6 TCP based
9 Non-GBR
9
(lowest)
300 10-6 TCP based
Bearer
LTE bearer
Characterized by
QoS
Standardized
QCI (QoS Class
Identifier)
EPS - Evolved Packet System
QCI - QoS Class ID
GBR - Guaranteed Bit Rate
R
Glossary
TS 23.203
57. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
Characterized by
Path in the network
Could be a function of transported data flow QoS requirements
Bearers carrying flows of same service could have different paths, if the flows require
different QoS
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
R
EPS - Evolved Packet System
Glossary
LTE bearer is characterized by
End points
QoS
Path in the network
Capsule structure
58. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
Characterized by
Capsule structure
Fields added by the bearer source to the packet to be transported (marking of original
user packet) for the capsule to reach its intended destination, while experiencing the
intended QoS
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
EPS bearer
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
R
EPS - Evolved Packet System
Glossary
LTE bearer is characterized by
End points
QoS
Path in the network
Capsule structure
59. BASIC TECHNOLOGIES
Flow / Service / Bearer
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
Radio bearer S1 bearer S5/S8 bearer
S1 bearer S5/S8 bearer
Radio bearer
Radio bearer S1 bearer S5/S8 bearer
Bearer
LTE bearer
Characterized by
Capsule structure
EPS bearer traverses multiple interfaces and technologies; capsule structure in each
section is different => the EPS bearer is in fact a concatenation of multiple bearers
Bearers are identified by Tunnel ID; Tunnel ID mapping from one bearer to another is
executed in the relevant devices, in each direction separately
R
EPS - Evolved Packet System
Glossary
LTE bearer is characterized by
End points
QoS
Path in the network
Capsule structure
60. BASIC TECHNOLOGIES
Flow / Service / Bearer
Bearer
LTE bearer
Default / dedicated bearer
At connection to network, UE receives automatically one default non-GBR EPS bearer up
to a P-GW; it provides to UE "always on" access to a pre-defined network (e.g. Internet)
UE can establish connections to additional networks; for each such network a default
non-GBR bearer is created
After the creation of the default bearer to a network, UE can create dedicated bearers to
same network, usually GBR
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
Radio bearer S1 bearer S5/S8 bearer
S1 bearer S5/S8 bearer
Radio bearer
Radio bearer S1 bearer S5/S8 bearer
EPS - Evolved Packet System
GBR - Guaranteed Bit Rate
R
Glossary
61. BASIC TECHNOLOGIES
Flow / Service / Bearer
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
AS
HQ
EPS bearer
non-EPS bearer to HQ
Voice
flow
Video
flow
Data
flow
Internet surf service
Video conf service
non-EPS bearer
to AS
Radio bearer S1 bearer S5/S8 bearer
S1 bearer S5/S8 bearer
Radio bearer
Radio bearer S1 bearer S5/S8 bearer
Bearer
LTE bearer
Mapping of packets to bearers is executed through a classification/filtering process that
checks different fields in the ingress packet (defined in TFT - Traffic Flow Template)(usually IP
DA/SA, Protocol field in IP header, UDP/TCP port, etc.), by
UE for UL traffic
P-GW for DL traffic
R
TFT - Traffic Flow Template
Glossary
62. BASIC TECHNOLOGIES
Flow / Service / Bearer
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
SGi
MME
S-GW1
S11 Rx
Bearer
LTE bearer
Mapping of packets to bearers is executed through a
classification/filtering process checking different fields in the
ingress packet (defined in TFT - Traffic Flow Template)
P-GW3
PDN 3
PDN 1
PDN 2
(usually IP DA/SA, Protocol field in IP header, UDP/TCP port, etc.), by
UE for UL traffic
P-GW for DL traffic
UL mapping - When mapping a packet to a bearer (tunnel), UE "knows" which application
generated the packet (=> it knows the destination net, the QoS expected, etc.) so mapping is well defined
DL mapping - When P-GW3 receives a packet from one of the PDNs, it has to consider the case
in which flows from different PDNs are defined by same fields values (i.e. have same TFT) but
expect different QoS ... (Same application used in both PDNs, but expecting different QoS). As
a result, P-GW3 has to identify the originating PDN ...
While PDN1 and PDN3 traffic could be differentiated based on their different ingress
ports, traffic from PDN1 and PDN2 can not be differentiated (they have same TFT and
arrive on same physical port) ... unless ...
R
R
TFT - Traffic Flow Template
PDN - Packet Data Network
Glossary
63. BASIC TECHNOLOGIES
Flow / Service / Bearer
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
SGi
MME
S-GW1
S11 Rx
TFT - Traffic Flow Template
P-GW3
PDN 3
PDN 1
PDN 2
Bearer
LTE bearer
DL mapping - When P-GW3 receives a packet from one of the
PDNs, it has to consider the case in which flows from
different PDNs are defined by same fields values (i.e. have
same TFT) but expect different QoS ... (Same application used in both PDNs, but expecting
different QoS). As a result, P-GW3 has to identify the originating PDN ...
While PDN1 and PDN3 traffic can be differentiated based on their different ingress
ports, traffic from PDN1 and PDN2 can not be differentiated (they have same TFT and
arrive on same physical port) ... unless ...
P-GW3 checks IP addresses of incoming packet
Checking SA - Assumes that P-GW keeps track of all IP SA in all PDNs to which it
provides access - impossible, too much info
Checking DA - Assumes that entities in each PDN address the SAME UE using
different IP addresses ... which implies that UE generated traffic uses different IP
SA when addressing different PDN
R
R
Glossary
64. BASIC TECHNOLOGIES
Flow / Service / Bearer
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
SGi
MME
S-GW1
S11 Rx
P-GW3
PDN 3
PDN 1
PDN 2
Bearer
LTE bearer
Conclusion
When a first bearer is created by UE (default, non-GBR) to
a PDN, the respective P-GW allocates to UE an IP address
to be used by UE as IP SA for all the traffic destined to the
respective PDN. For bearers created toward OTHER PDN, P-GW allocates to UE OTHER IP
address to be used as IP SA. This forces the traffic back from PDN to UE to arrive at P-GW
with IP DA that reflects the originating PDN!
The amount of IP addresses to be remembered by P-GW is equal to the number of PDNs to
which it is connected (significantly less than remembering ALL the users in those PDNs!)
Additional bearers created toward the SAME PDN use the IP address received when the
default bearer was created. There can be no identification problems as flows to SAME PDN
can not have SAME values for TFT fields and expect DIFFERENT QoS...
Different QoS expectations => different bearers => different values for TFT fields
R
R
Glossary
net1...
net2...
net3...
net4 ...
net5 ...
net5 c for traffic to PDN 3
net4 a for traffic to PDN 1
net4 b for traffic to PDN 2
Notes
net4.a, net4.b and net5.c have to be public addresses; reachability to them is advertised by routers R into their respective PDNs
For practical purposes, in IPv4, a NAT will be probably present between P-GW3 and each of the routers, translating UE's multiple IP addresses into one single IP address toward routers R. (UE has to be a Client)
UE has to support multiple simultaneous IP addresses
NAT - Network Address Translator
65. BASIC TECHNOLOGIES
APN - Access Point Name
eNB
eNB
Uu
S8
Uu
S6a
Gxc
X2
S10
UE
UE
PCRF
HSS
MME
S11
- Entity located in a diff. net
APN - Access Point Name
HSS - Home Subscriber Server
AMBR - Aggregate Max. Bit Rate
GBR - Guaranteed Bit Rate
PDN - Packet Data Network
PDN 1
APN
The name associated with a specific PDN
APN format: netID.OperatorID
The name of a table kept in HSS for each known UE,
indicating the rights of the respective UE in terms of access
to the PDN with same APN name [including APN-AMBR
PDN 3
PDN 2
P-GW3
(Aggregate Max Bit Rate) for all the non-GBR flows that the respective UE is allowed to inject
into the APN]
During the network entry process of a specific UE, MME gets from UE's HSS details related to
the APN(s) that UE has right to connect to (APN name, APN-AMBR, security parameters, etc.)
MME makes a query to DNS, for APN name; the response is a list of P-GWs that can be
used to access that PDN/APN (e.g. query for APN2 would result in coordinates of P-GW5,
P-GW3 and P-GW4; MME would select one of the P-GWs (based on internal algorithms)
as the one to be used for actual traffic.
Selected P-GW will then generate an IP address to be used by UE, for DL traffic
identification (see previous slide)
APN2
P-GW6
P-GW5
P-GW4
PDN 8
S-GW
P-GW8
S5
R
R
R
R
R
APN8
local
Glossary
66. BASIC TECHNOLOGIES
Access Stratum (AS) / Non Access Stratum (NAS)
SAE GW
eNB
eNB
Uu
S5/S8
Uu
S6a
Gxc
Gx/S7
X2
S10
UE
UE
PCRF
HSS
PDN /
IMS
SGi
P-GW3
MME
S-GW1
S11 Rx
Access Stratum (AS) messages
Control plane messages exchanged by Mobile Device with its Base Station, controlling
radio access related parameters
Different Radio Access Technologies (RAT) have different sets of AS messages
In LTE, AS messages / protocols are present between UE and eNB
Non Access Stratum (NAS) messages
Control plane messages exchanged by Mobile Device with the network itself, using RAT
section in a transparent / pass-through mode
NAS messages are not specific to a particular RAT
In LTE NAS messages / protocols are present between UE and MME for session
management and mobility management
R
Glossary RAT - Radio Access Technology
(N)AS - (Non) Access Stratum
AS traffic
NAS traffic