1. The document proposes an availability-aware routing algorithm for hybrid wireless-optical broadband access networks to improve network availability and throughput.
2. The algorithm calculates the availability of each link and path by considering the mean time to failure and mean time to repair of network components.
3. It finds the most available path between any source-destination pair using a modified Dijkstra's shortest path algorithm that assigns link weights based on availability. This helps route traffic along more reliable paths.
The document proposes Ethernet VPN (E-VPN) as a solution to overcome scaling challenges with the existing Virtual Private LAN Service (VPLS) technology. E-VPN uses MPLS and BGP to transport layer 2 connectivity between data centers. It treats MAC addresses as routable addresses and uses MP-iBGP to distribute customer MAC addresses between edge routers. This allows for remote MAC learning and helps scale to thousands of MAC addresses. The document also describes how E-VPN uses Ethernet Segment IDs and split horizon labels to avoid layer 2 loops in multi-homing scenarios.
Receive diversity uses two receive antennas at the mobile to improve signal reception on the uplink and downlink in LTE systems. Transmit diversity addresses the smaller separation between a mobile's antennas compared to a base station's antennas, using either closed-loop or open-loop techniques which provide feedback or no feedback to the transmitter, respectively. Spatial multiplexing further increases capacity by transmitting independent data streams simultaneously through multiple antennas to different users.
The document discusses the key requirements for 4G networks including high bandwidth, long distance, low power consumption, and high speed mobility. It then examines the characteristics of different duplexing techniques used in today's networks, specifically Frequency Division Duplex (FDD) and Time Division Duplex (TDD). The challenges of TDD including cross-slot interference and outdated channel information are also outlined, along with potential solutions like synchronization and sectorization. In conclusion, TDD allows for asymmetric traffic allocation and higher bit-rates using unpaired spectrum bands compared to FDD.
Hybrid decode-amplify and forward protocol of FD EH relaying network: outage ...TELKOMNIKA JOURNAL
Nowadays, many research papers focus on the WPCN problem and how to improve its
efficiency. In this research, we propose and investigate Hybrid Decode-Amplify and Forward Protocol
(HDAF) of the Full-Duplex (FD) Energy Harvesting (EH) Relaying Network with the Time Switching (TS)
protocol. In the beginning stage, we present the HDAF mode, which can be work like a
Decode-and-Amplify (DF) or Amplify-and-Forward (AF) modes based on the best of its performance in the
FD EH relaying network. Furthermore, the closed-form expression of the outage probability (OT) is
analyzed and derived in connection with the primary system parameters. Besides, the comparison of
the system performance in the AF, DF, and HDAF is proposed and investigated. Finally, all the results are
convinced by the Monte Carlo simulation for all cases.
The document discusses the differences between SDH and PDH, as well as key aspects of SDH. SDH provides higher transmission rates up to 40 Gbit/s, simplified add and drop functions, high availability and capacity matching, reliability, and is a future-proof platform for new services compared to PDH. SDH uses synchronous multiplexing where data from multiple sources is byte interleaved at fixed locations in the frame. This allows single channels to be dropped from the data stream without demultiplexing intermediate rates as required in PDH.
This document provides an overview of channel estimation strategies used in orthogonal frequency division multiplexing (OFDM) systems. It describes the basic types of channel estimation methods: block-type pilot channel estimation and comb-type pilot channel estimation. For block-type estimation, pilots are inserted into all subcarriers of OFDM symbols periodically. This allows estimation of the channel conditions between pilot symbols. Estimation can be done with least squares (LS), minimum mean-square error (MMSE), or modified MMSE. For comb-type estimation, pilots are inserted into certain subcarriers of each symbol, requiring interpolation to estimate data subcarriers. The document compares the implementation complexity and performance of different estimation methods.
The document discusses next generation synchronous digital hierarchy (NGN SDH) and provides an overview of the technology. It notes that traditional SDH networks have limitations in efficiently transporting Ethernet traffic. NGN SDH aims to address this through features like virtual concatenation, which allows flexible and efficient transport of Ethernet services over existing SDH infrastructure.
Cell-specific reference signals are transmitted in all downlink subframes in a cell and are used by UEs to determine phase reference and channel quality. UE-specific reference signals may also be transmitted and are embedded only in resource blocks allocated to a specific UE. Reference signals include cell-specific, UE-specific, positioning, and multicast signals. Uplink reference signals include demodulation reference signals transmitted by each UE and sounding reference signals transmitted separately to aid base station channel estimation. In LTE, channels are estimated using reference signals and channel state information in the form of precoding matrix, rank, and channel quality indicators is implicitly feedback to the base station to enable adaptive transmission.
The document proposes Ethernet VPN (E-VPN) as a solution to overcome scaling challenges with the existing Virtual Private LAN Service (VPLS) technology. E-VPN uses MPLS and BGP to transport layer 2 connectivity between data centers. It treats MAC addresses as routable addresses and uses MP-iBGP to distribute customer MAC addresses between edge routers. This allows for remote MAC learning and helps scale to thousands of MAC addresses. The document also describes how E-VPN uses Ethernet Segment IDs and split horizon labels to avoid layer 2 loops in multi-homing scenarios.
Receive diversity uses two receive antennas at the mobile to improve signal reception on the uplink and downlink in LTE systems. Transmit diversity addresses the smaller separation between a mobile's antennas compared to a base station's antennas, using either closed-loop or open-loop techniques which provide feedback or no feedback to the transmitter, respectively. Spatial multiplexing further increases capacity by transmitting independent data streams simultaneously through multiple antennas to different users.
The document discusses the key requirements for 4G networks including high bandwidth, long distance, low power consumption, and high speed mobility. It then examines the characteristics of different duplexing techniques used in today's networks, specifically Frequency Division Duplex (FDD) and Time Division Duplex (TDD). The challenges of TDD including cross-slot interference and outdated channel information are also outlined, along with potential solutions like synchronization and sectorization. In conclusion, TDD allows for asymmetric traffic allocation and higher bit-rates using unpaired spectrum bands compared to FDD.
Hybrid decode-amplify and forward protocol of FD EH relaying network: outage ...TELKOMNIKA JOURNAL
Nowadays, many research papers focus on the WPCN problem and how to improve its
efficiency. In this research, we propose and investigate Hybrid Decode-Amplify and Forward Protocol
(HDAF) of the Full-Duplex (FD) Energy Harvesting (EH) Relaying Network with the Time Switching (TS)
protocol. In the beginning stage, we present the HDAF mode, which can be work like a
Decode-and-Amplify (DF) or Amplify-and-Forward (AF) modes based on the best of its performance in the
FD EH relaying network. Furthermore, the closed-form expression of the outage probability (OT) is
analyzed and derived in connection with the primary system parameters. Besides, the comparison of
the system performance in the AF, DF, and HDAF is proposed and investigated. Finally, all the results are
convinced by the Monte Carlo simulation for all cases.
The document discusses the differences between SDH and PDH, as well as key aspects of SDH. SDH provides higher transmission rates up to 40 Gbit/s, simplified add and drop functions, high availability and capacity matching, reliability, and is a future-proof platform for new services compared to PDH. SDH uses synchronous multiplexing where data from multiple sources is byte interleaved at fixed locations in the frame. This allows single channels to be dropped from the data stream without demultiplexing intermediate rates as required in PDH.
This document provides an overview of channel estimation strategies used in orthogonal frequency division multiplexing (OFDM) systems. It describes the basic types of channel estimation methods: block-type pilot channel estimation and comb-type pilot channel estimation. For block-type estimation, pilots are inserted into all subcarriers of OFDM symbols periodically. This allows estimation of the channel conditions between pilot symbols. Estimation can be done with least squares (LS), minimum mean-square error (MMSE), or modified MMSE. For comb-type estimation, pilots are inserted into certain subcarriers of each symbol, requiring interpolation to estimate data subcarriers. The document compares the implementation complexity and performance of different estimation methods.
The document discusses next generation synchronous digital hierarchy (NGN SDH) and provides an overview of the technology. It notes that traditional SDH networks have limitations in efficiently transporting Ethernet traffic. NGN SDH aims to address this through features like virtual concatenation, which allows flexible and efficient transport of Ethernet services over existing SDH infrastructure.
Cell-specific reference signals are transmitted in all downlink subframes in a cell and are used by UEs to determine phase reference and channel quality. UE-specific reference signals may also be transmitted and are embedded only in resource blocks allocated to a specific UE. Reference signals include cell-specific, UE-specific, positioning, and multicast signals. Uplink reference signals include demodulation reference signals transmitted by each UE and sounding reference signals transmitted separately to aid base station channel estimation. In LTE, channels are estimated using reference signals and channel state information in the form of precoding matrix, rank, and channel quality indicators is implicitly feedback to the base station to enable adaptive transmission.
SONET-SDH is the digital infrastructure that telephone networks are largely based on today. It uses Time Division Multiplexing (TDM) and strict synchronization. Key components of SONET-SDH include SONET for North America, SDH for Europe and Japan, and STS for electrical signals. SONET-SDH was developed to replace the older Plesiochronous Digital Hierarchy (PDH) standard due to lack of scalability and synchronization issues. SONET-SDH defines a structured multiplexing hierarchy, management and protection mechanisms, and physical layer requirements to provide fault tolerance, interoperability, flexibility, and network monitoring capabilities.
This document summarizes LTE uplink transport channel processing and physical layer procedures. It discusses:
1. Uplink transport channel processing including channel coding and modulation for uplink shared channels and uplink control information.
2. Physical layer procedures including uplink reference signals, random access channels, HARQ, channel quality indicator feedback, and scheduling.
3. Specific topics covered include SC-FDMA modulation for the uplink, uplink reference signal structure, PUCCH formats for control information, and coding schemes for different control information types.
The document summarizes a study on simulating a cognitive radio system using different wireless channel models. The study evaluated the performance of an energy detector for spectrum sensing in the cognitive radio system. Three channel models were considered: (1) Additive White Gaussian Noise channel, (2) Rayleigh fading channel, and (3) Rician fading channel. The simulation results showed that the detection capability of the energy detector improved with increasing signal-to-noise ratio, and the probabilities of false alarm and missed detection decreased. The Rician fading model, which includes a line-of-sight path, had a significant impact on energy detector performance compared to the other models.
This document provides an overview of OFDM and the downlink physical layer design in LTE. It discusses why OFDM is necessary for high data rates in LTE, describing how OFDM avoids intersymbol interference through the use of multiple orthogonal subcarriers. It then covers OFDM signal structure and modulation, including the transmitter and receiver designs based on the inverse discrete Fourier transform and discrete Fourier transform. The document also introduces the concept of a guard interval to eliminate intersymbol interference and provides a matrix representation of multicarrier systems using cyclic prefix and DFT/IDFT.
SONET and SDH are standards for synchronous optical networking. They were developed to address limitations in earlier PDH digital telephony networks, such as increasing overhead percentages and lack of interoperability between regional systems. SONET/SDH uses a layered architecture with standardized rates and frame structures. It defines optical, line, and path layers to transport digital signals end-to-end with integrated operations, administration, and maintenance capabilities. This allows flexible and efficient transport of diverse payloads, including PDH, ATM, and packet data, over optical networks on a global scale.
Short survey for Channel estimation using OFDM systemsMohamed Seif
This document discusses channel estimation techniques for OFDM systems. It begins by introducing OFDM and the need for channel state information at the receiver. It then describes two common pilot arrangements - block and comb type. For block pilots, it examines least squares and minimum mean square error channel estimation. It finds MMSE performs better but with higher complexity. For comb pilots, it presents least squares and LMS estimation as well as interpolation techniques between pilot tones. The document also evaluates channel estimation for MIMO-OFDM and the effects of user mobility.
This document discusses implementing OFDM modulation and demodulation using cyclic prefix insertion and removal. It describes sharing an FFT module between transmission and reception paths in TDD and FDD systems through multiplexing signals and buffering pre-FFT data. The example implementation supports variable FFT sizes and cyclic prefix lengths, and reuse of control modules for both transmission and reception in a TDD system. It uses dual-port RAMs and backpressure to efficiently perform cyclic prefix insertion after IFFT and rate change before and after FFT.
MIMO Channel Estimation Using the LS and MMSE AlgorithmIOSRJECE
Wireless Communication Technology has developed over the past few yearsfor other objectives.The Multiple InputMultiple Output (MIMO) is one of techniques that is used to enhancethe data rates, in which multiple antennas are employed both the transmitter and receiver. Multiple signals are transmitted from different antennas at the transmitter using the same frequency and separated space. Various channel estimation techniques are employed in order to judge the physical effects of the medium present. In this paper, we analyze and implementvarious estimation techniques for MIMO Systems such as Least Squares (LS), Minimum Mean Square Error (MMSE),these techniques are therefore compared to effectively estimate the channel in MIMO System. The results demonstrate that SNR required to support different values of bit error rate varies depending on different low correlation between the transmitting and the receiving antennas .In addition, it is illustrated that when the number of transmitter and receiver antennas increases, the performance of TBCE schemes significantly improves. The Same behavior isalso observed for MIMO system. Performance of both MMSE and LSestimation are the same for allkinds of modulation at small value of SNR but the more we increase the SNR value the more performance gap goes on increasing.
WC & LTE 4G Broadband Module 2- 2019 by Prof.Suresha VSURESHA V
This document discusses multicarrier modulation techniques used in LTE, focusing on OFDM, OFDMA, and SC-FDMA. It covers the basics of OFDM including how it divides a high-rate data stream into multiple parallel low-rate substreams to mitigate intersymbol interference. The cyclic prefix is discussed as a guard interval to eliminate intercarrier interference. OFDMA and SC-FDMA are described as incorporating frequency division multiple access into OFDM. The document also reviews spatial diversity and multiplexing techniques used in LTE systems.
This document summarizes an OFDM channel estimation project. It discusses the objective to maximize OFDM system capacity through channel estimation and adaptive transmission. It outlines the system architecture, including the transmitter, channel, receiver, and channel estimation. It also lists the work completed, such as programs for channel impulse response, Rayleigh fading, and adding noise.
This paper aims, a 3D-Pilot Aided Multi-Input Multi-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) Channel Estimation (CE) for Digital Video Broadcasting -T2 (DVB-T2) for the 5 different proposed block and comb pilot patterns model and performed on different antenna configuration. The effects of multi-transceiver antenna on channel estimation are addressed with different pilot position in frequency, time and the vertical direction of spatial domain framing. This paper first focus on designing of 5-different proposed spatial correlated pilot pattern model with optimization of pilot overhead. Then it demonstrates the performance comparison of Least Square (LS) & Linear Minimum Mean Square Error (LMMSE), two linear channel estimators for 3D-Pilot Aided patterns on different antenna configurations in terms of Bit Error Rate. The simulation results are shown for Rayleigh fading noise channel environments. Also, 3x4 MIMO configuration is recommended as the most suitable configuration in this noise channel environments.
This document provides a technical overview of Ethernet services based on work by the Metro Ethernet Forum (MEF) Technical Committee. It defines key terms like Ethernet Virtual Connection (EVC) and describes the two main Ethernet service types - Ethernet Line (E-Line) and Ethernet LAN (E-LAN). E-Line provides point-to-point connectivity between sites while E-LAN provides multipoint connectivity between multiple sites using a single EVC. The document outlines various attributes that define Ethernet services, like physical interface specifications, bandwidth profiles, and performance parameters.
Combining SFBC_OFDM Systems with SVD Assisted Multiuser Transmitter and Multi...IOSR Journals
Abstract: In this work, we exploit the SVD assisted multiuser transmitter (MUT) and multiuser detector (MUD) technique, using downlink (DL) preprocessing transmitter and DL postprocessing receiver matrice .In combination with space frequency block coding (SFBC). And also propose the precoded DL transmission scheme, were the both proposed schemes take advantage of the channel state information (CSI) of all users at the base station (BS), but only of the mobile station (MS)’s own CSI, to decompose the MU MIMO channels into parallel single input single output (SISO), these two proposed schemes are compared to the vertical layered space time (V_BLAST) combined with SFBC (SFBC_VBLAST). Our Simulation results show that the performance of the proposed scheme with DL Zero Forcing (ZF) transmitter for interference canceller outperforms the SFBC_VBLAST and the precoded DL schemes with ZF receiver in frequency selective fading channels. Keywords – Post processing, Preprocessing,, SFBC, SVD, ZF.
This document provides a summary of a survey paper on Single Carrier Frequency Division Multiple Access (SC-FDMA) as an efficient technique for Peak-to-Average Power Ratio (PAPR) reduction in uplink communication systems. SC-FDMA was adopted for uplink transmission in Long Term Evolution (LTE) due to its lower PAPR compared to OFDMA. SC-FDMA applies a DFT pre-coding to OFDMA signals before transmission, which converts the multi-carrier signal into a single-carrier signal and significantly reduces the PAPR. The document discusses the limitations of OFDM including high PAPR, and various PAPR reduction techniques for OFDM such as clipping,
The most important RF technology change in 5G NR is the application of 3D-MIMO large-scale array antenna technology so that a considerable part of the NR physical layer architecture design content is adapted and updated around the technology. Here is a comparative perspective on the 5G system. 3D-MIMO antenna technology is introduced.
The document summarizes key aspects of channel estimation for wireless OFDM communications. It discusses the history and development of OFDM, including how the use of IFFT/FFT allows for practical implementation. It also describes how cyclic prefixes maintain orthogonality over multipath channels by converting linear convolution to circular convolution. The document then provides the continuous-time model for an OFDM transceiver system, showing how information symbols are modulated onto orthogonal subcarriers within an OFDM symbol structure that includes a cyclic prefix.
Phydyas 09 fFilter Bank Multicarrier (FBMC): An Integrated Solution to Spectr...Marwan Hammouda
The document discusses filter bank multicarrier (FBMC) as a solution for spectrum sensing and data transmission in cognitive radio networks. Conventional OFDM has limitations for these tasks due to its sidelobe leakage, which causes interference between primary and secondary users. FBMC uses a filter bank approach instead of FFT to provide better frequency localization and reduce sidelobe leakage without reducing bandwidth efficiency. The document outlines the benefits of FBMC over OFDM for spectrum sensing and sharing in cognitive radio.
Performance analysis of DWT based OFDM over FFT based OFDM and implementing o...VLSICS Design
Growth in technology has led to unprecedented demand for high speed architectures for complex signal processing applications. In 4G wireless communication systems, bandwidth is a precious commodity, and service providers are continuously met with the challenge of accommodating more users with in a limited allocated bandwidth. To increase data rate of wireless medium with higher performance, OFDM (orthogonal frequency division multiplexing) is used. Recently DWT (Discrete wavelet transforms) is adopted in place of FFT (Fast Fourier transform) for frequency translation. Modulation schemes such as 16-QAM, 32-QAM, 64-QAM and 128-QAM (Quadrature amplitude modulation) have been used in the developed OFDM system for both DWT and FFT based model. In this paper we propose a DWT-IDWT based OFDM transmitter and receiver that achieve better performance in terms SNR and BER for AWGN channel. It proves all the wavelet families better over the IFFT-FFT implementation. The OFDM model is developed using Simulink, various test cases have been considered to verify its performance. The DWTOFDM using Lifting Scheme architecture is implemented on FPGA optimizing hardware, speed & cost. The wavelet filter used for this is Daubechies (9, 7) with N=2. The RTL code is written in Verilog-HDL and simulated in Modelsim. The design is then synthesized in Xilinx and implemented on Virtex5 FPGA board and the results were validated using ChipScope.
Kanye West is known for doing things differently and pushing boundaries in hip hop music. Some of his early hits like "Through the Wire" established his rap style while produced for artists like Jay-Z. His 2010 album "My Beautiful Dark Twisted Fantasy" marked a return to rap roots with features from various artists across genres. The music video for "Runaway" from this album was an epic, movie-length collaboration that helped propel the album's success.
1) The document introduces rules for a debate on what the Earth will look like in 20 years, asking participants to submit video responses.
2) The rules require responses to think philosophically by making a point, providing an example, and citing evidence. Only video responses are allowed to avoid flame wars.
3) Participants must understand other perspectives before stating their own and can form alliances while avoiding repetition. Respect and dignity toward other opinions is also required.
4) Responses will be judged based on the number of likes received, though the author will check for bias. The debate aims to be thought-provoking rather than antagonistic.
SONET-SDH is the digital infrastructure that telephone networks are largely based on today. It uses Time Division Multiplexing (TDM) and strict synchronization. Key components of SONET-SDH include SONET for North America, SDH for Europe and Japan, and STS for electrical signals. SONET-SDH was developed to replace the older Plesiochronous Digital Hierarchy (PDH) standard due to lack of scalability and synchronization issues. SONET-SDH defines a structured multiplexing hierarchy, management and protection mechanisms, and physical layer requirements to provide fault tolerance, interoperability, flexibility, and network monitoring capabilities.
This document summarizes LTE uplink transport channel processing and physical layer procedures. It discusses:
1. Uplink transport channel processing including channel coding and modulation for uplink shared channels and uplink control information.
2. Physical layer procedures including uplink reference signals, random access channels, HARQ, channel quality indicator feedback, and scheduling.
3. Specific topics covered include SC-FDMA modulation for the uplink, uplink reference signal structure, PUCCH formats for control information, and coding schemes for different control information types.
The document summarizes a study on simulating a cognitive radio system using different wireless channel models. The study evaluated the performance of an energy detector for spectrum sensing in the cognitive radio system. Three channel models were considered: (1) Additive White Gaussian Noise channel, (2) Rayleigh fading channel, and (3) Rician fading channel. The simulation results showed that the detection capability of the energy detector improved with increasing signal-to-noise ratio, and the probabilities of false alarm and missed detection decreased. The Rician fading model, which includes a line-of-sight path, had a significant impact on energy detector performance compared to the other models.
This document provides an overview of OFDM and the downlink physical layer design in LTE. It discusses why OFDM is necessary for high data rates in LTE, describing how OFDM avoids intersymbol interference through the use of multiple orthogonal subcarriers. It then covers OFDM signal structure and modulation, including the transmitter and receiver designs based on the inverse discrete Fourier transform and discrete Fourier transform. The document also introduces the concept of a guard interval to eliminate intersymbol interference and provides a matrix representation of multicarrier systems using cyclic prefix and DFT/IDFT.
SONET and SDH are standards for synchronous optical networking. They were developed to address limitations in earlier PDH digital telephony networks, such as increasing overhead percentages and lack of interoperability between regional systems. SONET/SDH uses a layered architecture with standardized rates and frame structures. It defines optical, line, and path layers to transport digital signals end-to-end with integrated operations, administration, and maintenance capabilities. This allows flexible and efficient transport of diverse payloads, including PDH, ATM, and packet data, over optical networks on a global scale.
Short survey for Channel estimation using OFDM systemsMohamed Seif
This document discusses channel estimation techniques for OFDM systems. It begins by introducing OFDM and the need for channel state information at the receiver. It then describes two common pilot arrangements - block and comb type. For block pilots, it examines least squares and minimum mean square error channel estimation. It finds MMSE performs better but with higher complexity. For comb pilots, it presents least squares and LMS estimation as well as interpolation techniques between pilot tones. The document also evaluates channel estimation for MIMO-OFDM and the effects of user mobility.
This document discusses implementing OFDM modulation and demodulation using cyclic prefix insertion and removal. It describes sharing an FFT module between transmission and reception paths in TDD and FDD systems through multiplexing signals and buffering pre-FFT data. The example implementation supports variable FFT sizes and cyclic prefix lengths, and reuse of control modules for both transmission and reception in a TDD system. It uses dual-port RAMs and backpressure to efficiently perform cyclic prefix insertion after IFFT and rate change before and after FFT.
MIMO Channel Estimation Using the LS and MMSE AlgorithmIOSRJECE
Wireless Communication Technology has developed over the past few yearsfor other objectives.The Multiple InputMultiple Output (MIMO) is one of techniques that is used to enhancethe data rates, in which multiple antennas are employed both the transmitter and receiver. Multiple signals are transmitted from different antennas at the transmitter using the same frequency and separated space. Various channel estimation techniques are employed in order to judge the physical effects of the medium present. In this paper, we analyze and implementvarious estimation techniques for MIMO Systems such as Least Squares (LS), Minimum Mean Square Error (MMSE),these techniques are therefore compared to effectively estimate the channel in MIMO System. The results demonstrate that SNR required to support different values of bit error rate varies depending on different low correlation between the transmitting and the receiving antennas .In addition, it is illustrated that when the number of transmitter and receiver antennas increases, the performance of TBCE schemes significantly improves. The Same behavior isalso observed for MIMO system. Performance of both MMSE and LSestimation are the same for allkinds of modulation at small value of SNR but the more we increase the SNR value the more performance gap goes on increasing.
WC & LTE 4G Broadband Module 2- 2019 by Prof.Suresha VSURESHA V
This document discusses multicarrier modulation techniques used in LTE, focusing on OFDM, OFDMA, and SC-FDMA. It covers the basics of OFDM including how it divides a high-rate data stream into multiple parallel low-rate substreams to mitigate intersymbol interference. The cyclic prefix is discussed as a guard interval to eliminate intercarrier interference. OFDMA and SC-FDMA are described as incorporating frequency division multiple access into OFDM. The document also reviews spatial diversity and multiplexing techniques used in LTE systems.
This document summarizes an OFDM channel estimation project. It discusses the objective to maximize OFDM system capacity through channel estimation and adaptive transmission. It outlines the system architecture, including the transmitter, channel, receiver, and channel estimation. It also lists the work completed, such as programs for channel impulse response, Rayleigh fading, and adding noise.
This paper aims, a 3D-Pilot Aided Multi-Input Multi-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) Channel Estimation (CE) for Digital Video Broadcasting -T2 (DVB-T2) for the 5 different proposed block and comb pilot patterns model and performed on different antenna configuration. The effects of multi-transceiver antenna on channel estimation are addressed with different pilot position in frequency, time and the vertical direction of spatial domain framing. This paper first focus on designing of 5-different proposed spatial correlated pilot pattern model with optimization of pilot overhead. Then it demonstrates the performance comparison of Least Square (LS) & Linear Minimum Mean Square Error (LMMSE), two linear channel estimators for 3D-Pilot Aided patterns on different antenna configurations in terms of Bit Error Rate. The simulation results are shown for Rayleigh fading noise channel environments. Also, 3x4 MIMO configuration is recommended as the most suitable configuration in this noise channel environments.
This document provides a technical overview of Ethernet services based on work by the Metro Ethernet Forum (MEF) Technical Committee. It defines key terms like Ethernet Virtual Connection (EVC) and describes the two main Ethernet service types - Ethernet Line (E-Line) and Ethernet LAN (E-LAN). E-Line provides point-to-point connectivity between sites while E-LAN provides multipoint connectivity between multiple sites using a single EVC. The document outlines various attributes that define Ethernet services, like physical interface specifications, bandwidth profiles, and performance parameters.
Combining SFBC_OFDM Systems with SVD Assisted Multiuser Transmitter and Multi...IOSR Journals
Abstract: In this work, we exploit the SVD assisted multiuser transmitter (MUT) and multiuser detector (MUD) technique, using downlink (DL) preprocessing transmitter and DL postprocessing receiver matrice .In combination with space frequency block coding (SFBC). And also propose the precoded DL transmission scheme, were the both proposed schemes take advantage of the channel state information (CSI) of all users at the base station (BS), but only of the mobile station (MS)’s own CSI, to decompose the MU MIMO channels into parallel single input single output (SISO), these two proposed schemes are compared to the vertical layered space time (V_BLAST) combined with SFBC (SFBC_VBLAST). Our Simulation results show that the performance of the proposed scheme with DL Zero Forcing (ZF) transmitter for interference canceller outperforms the SFBC_VBLAST and the precoded DL schemes with ZF receiver in frequency selective fading channels. Keywords – Post processing, Preprocessing,, SFBC, SVD, ZF.
This document provides a summary of a survey paper on Single Carrier Frequency Division Multiple Access (SC-FDMA) as an efficient technique for Peak-to-Average Power Ratio (PAPR) reduction in uplink communication systems. SC-FDMA was adopted for uplink transmission in Long Term Evolution (LTE) due to its lower PAPR compared to OFDMA. SC-FDMA applies a DFT pre-coding to OFDMA signals before transmission, which converts the multi-carrier signal into a single-carrier signal and significantly reduces the PAPR. The document discusses the limitations of OFDM including high PAPR, and various PAPR reduction techniques for OFDM such as clipping,
The most important RF technology change in 5G NR is the application of 3D-MIMO large-scale array antenna technology so that a considerable part of the NR physical layer architecture design content is adapted and updated around the technology. Here is a comparative perspective on the 5G system. 3D-MIMO antenna technology is introduced.
The document summarizes key aspects of channel estimation for wireless OFDM communications. It discusses the history and development of OFDM, including how the use of IFFT/FFT allows for practical implementation. It also describes how cyclic prefixes maintain orthogonality over multipath channels by converting linear convolution to circular convolution. The document then provides the continuous-time model for an OFDM transceiver system, showing how information symbols are modulated onto orthogonal subcarriers within an OFDM symbol structure that includes a cyclic prefix.
Phydyas 09 fFilter Bank Multicarrier (FBMC): An Integrated Solution to Spectr...Marwan Hammouda
The document discusses filter bank multicarrier (FBMC) as a solution for spectrum sensing and data transmission in cognitive radio networks. Conventional OFDM has limitations for these tasks due to its sidelobe leakage, which causes interference between primary and secondary users. FBMC uses a filter bank approach instead of FFT to provide better frequency localization and reduce sidelobe leakage without reducing bandwidth efficiency. The document outlines the benefits of FBMC over OFDM for spectrum sensing and sharing in cognitive radio.
Performance analysis of DWT based OFDM over FFT based OFDM and implementing o...VLSICS Design
Growth in technology has led to unprecedented demand for high speed architectures for complex signal processing applications. In 4G wireless communication systems, bandwidth is a precious commodity, and service providers are continuously met with the challenge of accommodating more users with in a limited allocated bandwidth. To increase data rate of wireless medium with higher performance, OFDM (orthogonal frequency division multiplexing) is used. Recently DWT (Discrete wavelet transforms) is adopted in place of FFT (Fast Fourier transform) for frequency translation. Modulation schemes such as 16-QAM, 32-QAM, 64-QAM and 128-QAM (Quadrature amplitude modulation) have been used in the developed OFDM system for both DWT and FFT based model. In this paper we propose a DWT-IDWT based OFDM transmitter and receiver that achieve better performance in terms SNR and BER for AWGN channel. It proves all the wavelet families better over the IFFT-FFT implementation. The OFDM model is developed using Simulink, various test cases have been considered to verify its performance. The DWTOFDM using Lifting Scheme architecture is implemented on FPGA optimizing hardware, speed & cost. The wavelet filter used for this is Daubechies (9, 7) with N=2. The RTL code is written in Verilog-HDL and simulated in Modelsim. The design is then synthesized in Xilinx and implemented on Virtex5 FPGA board and the results were validated using ChipScope.
Kanye West is known for doing things differently and pushing boundaries in hip hop music. Some of his early hits like "Through the Wire" established his rap style while produced for artists like Jay-Z. His 2010 album "My Beautiful Dark Twisted Fantasy" marked a return to rap roots with features from various artists across genres. The music video for "Runaway" from this album was an epic, movie-length collaboration that helped propel the album's success.
1) The document introduces rules for a debate on what the Earth will look like in 20 years, asking participants to submit video responses.
2) The rules require responses to think philosophically by making a point, providing an example, and citing evidence. Only video responses are allowed to avoid flame wars.
3) Participants must understand other perspectives before stating their own and can form alliances while avoiding repetition. Respect and dignity toward other opinions is also required.
4) Responses will be judged based on the number of likes received, though the author will check for bias. The debate aims to be thought-provoking rather than antagonistic.
Elsevier has launched its Asia e-bookshop, offering over 4000 medical titles across many disciplines including dentistry, nursing, allied health, and veterinary. The bookshop aims to be a one-stop shop for academics, students, health professionals and practitioners in Asia, offering free delivery regardless of purchase amount. It covers a wide range of topics including dental titles, health profession publications, medical titles, nursing textbooks, and veterinary medicine resources. Customers can also pre-order upcoming titles and sign up for alerts about sales and new releases.
The Queensway Shopping Center has a large interior with many shops selling good products. The shopping center aims to attract teenage customers and sports enthusiasts. It is likely to successfully attract customers because it sells desirable goods catering to teenagers.
UAD and UCDP Seminar - Coester Appraisal ManagementBrian Coester
Coester Appraisal Group a nationwide appraisal management company offers its clients and vendors educational material on the UCDP and UAD changes mandated by Fannie Mae and Freddie Mac. www.coesterappraisals.com
Have you considered hiring a property manager for your income properties? This presentation will give you some reasons why you might want to consider speaking to a management company.
This document investigates various wavelength-shifting compounds to improve counting efficiency when 32P-Cerenkov radiation is measured in aqueous samples. Of the compounds tested, esculin, β-methyl-umbelliferon, and sodium salicylate led to the greatest improvement in counting efficiency, by factors of about 1.3, 1.2, and 1.2, respectively. The concentrations and pH levels of these compounds were also examined to determine optimal conditions. Using ethanol as a solvent along with wavelength shifters soluble in both water and ethanol did not improve counting efficiency compared to using water alone.
Introduction to Online Lead Generation Approved Indexlukeybwy
An Introduction to Approved Index. Why We are the Online Lead Generation Experts and The History of Approved Index, How we Generate Our Leads, How we Compare to Other Methods of Lead Generation
Wireless Reducing Overall Delay In Multi Radio WobanShahab Shahid
The document proposes a technique to reduce overall delay in multi-radio wireless-optical broadband access networks (WOBANs) with minimal per-node processing overhead on data packets. WOBANs combine the high-speed, high-bandwidth optical back-end with a wireless front-end to provide flexible broadband access. However, the wireless front-end introduces delays from transmission, queueing, and synchronization at nodes. The authors aim to minimize these delays to match the performance of the optical back-end. They discuss existing routing algorithms for WOBANs and their limitations in addressing delays and load balancing. The proposed technique is intended to choose paths with minimal delay and maximize throughput while balancing network loads.
This document provides an overview of Greek gods and mythology and suggests student projects related to each god. It introduces Zeus as the ruler of Mount Olympus and suggests comparing Greek and Disney versions of Hercules. Student projects on gods like Aphrodite, Demeter, and Hephaestus involve journal entries or videos comparing myths to modern stories. Apollo and Artemis projects focus on their domains of music/healing and hunting. The document encourages reviewing Greek mythology through online quizzes and games.
This document is a peer-reviewed full-text paper published in the proceedings of ICC 2008 that proposes an efficient routing algorithm called CaDAR for wireless-optical broadband access networks (WOBANs). CaDAR aims to minimize delay and increase capacity in the wireless mesh network portion of a WOBAN by assigning capacities to links based on their states and calculating shortest delay paths between wireless nodes and gateways. The paper contributes by proposing the CaDAR algorithm and providing a comparative performance analysis of CaDAR with other approaches.
UCDP and UAD Appraisal Compliance Data set. Coester ApBrian Coester
Coester Appraisal Group, a nationwide appraisal management company, is ready for the Uniform Collateral Data Portal, better known as the Uniform Appraisal Dataset that will be available for use on June 27th, 2011 and required on or after March 19th, 2012 for all loans being submitted to Fannie Mae and/or Freddie Mac.
We hosted a series of webinar, which is part of a series of online educational programs hosted by Coester Appraisal Group. We will be continually updating and holding seminars and webinars for our lender clients. Please look below and look for updates.
The document provides a summary of top selling books available on Elsevier Asia's new e-bookshop. It lists 15 books covering various medical disciplines including anesthesia, dermatology, cardiology, surgery, orthopedics, and more. For each book, it provides the title, edition, author(s), number of pages, imprint, ISBN, and copyright. Users can click on the provided links for more information on each book.
Adjacent Channel Interference In IEEE 802.11 NAsia Smith
This document analyzes the effects of adjacent channel interference (ACI) on the IEEE 802.11n wireless networking standard. It finds that ACI can cause both a variant of the exposed terminal problem, where carrier sensing prevents concurrent transmissions, as well as a variant of the hidden terminal problem, where ACI causes packet collisions. Experimental results show that the number of available orthogonal channels depends on factors like the spatial separation between radios, channel width, frequency band, and traffic patterns. In multi-radio systems with little separation between antennas, ACI significantly reduces the number of usable channels.
This paper presents a novel data and timed control routing protocol which is Flying Adhoc Network (FANET) specific. The developed FANET specific routing protocol laid emphasis on the route connectivity in the network by considering the captured data size, minimum allowable distance between randomly moving nodes and connection time. The performance of the proposed FANET specific routing protocol was simulated using NS3. The obtained throughput value for the routing protocol fluctuated between 742.064kbps and 755.083kbps as data are exchanged between nodes. This showed that when all the UAVs are on the network and communicating with one another, the throughput is flatline and not plummet. This implies consistency as nodes join and leave the network. The packet delivery ratio obtained for the FSRP during simulation was 96.13%. These results implied that data is successfully transmitted between the UAV acting as server and UAV acting as client on the network.
Cyclic Sensing MAC Protocol for Multicast Routing in Mobilessrgjournals
This document summarizes a research paper that proposes a new MAC protocol called Dual Sensing MAC Protocol to address issues like deafness, hidden terminals, and exposed terminals when using directional antennas in mobile ad-hoc networks. The protocol uses a dual channel approach with one channel for data and another for control signals like busy tones. It employs mechanisms like DRTS, DCTS, and busy tones to help nodes determine the status of ongoing transmissions and avoid collisions. The protocol is validated using the SPIN tool and shown to successfully address the problems without blocking. Simulation results using NS2 demonstrate that the proposed protocol achieves higher packet delivery ratios than existing protocols.
This document compares SONET and DWDM network architectures through modeling a sample metro network. It finds:
1) For lower bandwidth demands like OC-3, SONET is more cost effective until traffic reaches around 16-20 Gbps, at which point DWDM becomes cheaper.
2) Higher bandwidth demands like OC-48 and Gigabit Ethernet favor DWDM, which overtakes SONET around 60-65 Gbps of traffic.
3) The SONET overlay approach delays but does not prevent the crossover points where DWDM becomes more cost effective than SONET.
4) Factors like span distances, fiber costs, and inclusion of lower bandwidth services can influence
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Prediction Algorithm for Mobile Ad Hoc Network Connection BreaksIJCNCJournal
A Mobile Ad-Hoc Network (MANET) is a decentralized network of mobile node that are connected to an arbitrary topology via wireless connections. The breakdown of the connecting links between adjacent nodes will probably lead to the loss of the transferred data packets. In this research, we proposed an algorithm for link prediction (LP) to enhance the link break provision of the ad hoc on-demand remote protocol (AODV). The proposed algorithm is called the AODV Link Break Prediction (AODVLBP). The AODVLBP prevents link breaks by the use of a predictive measure of the changing signal. The AODVLBP was evaluated using the network simulator version 2.35 (NS2) and compared with the AODV Link prediction (AODVLP) and the AODV routing protocols. The simulation results reveal the effectiveness of AODVLBP in improving network performance in terms of average end-to-end delay, packet delivery ratio, packet overhead ratio, and packet drop-neighbour break.
Detecting Good Neighbor Nodes and Finding Reliable Routing Path Based on AODV...IOSR Journals
Wireless operations allow services, such as long-range communications, that are impossible or
impractical to implement with the use of wires. It is supported by well-liked technique known as Adhoc Protocol
[1]. The term is commonly used in the telecommunications industry to refer to telecommunications systems e.g.
radio transmitters and receivers, remote controls etc. which use some form of energy e.g. radio waves, acoustic
energy, etc. to transfer information without the use of wires.[1] Information is transferred in this manner over
both short and long distances.In this, routes may be detached due to lively movement of nodes. So route
assortment and topology grouping is not easy and demanding issue. This type of networks is more vulnerable to
both internal and external attacks due to presence of wicked neighbour nodes[1][2s. Paper see the sights new
method using AODV protocol to find out good neighbour node and finding reliable path according to their
signal strength, flow capacity relative position of node in network.
Performance comparison of aodv and olsr using 802.11 a and dsrc (802.11p) pro...IJCNCJournal
A Vehicular Ad Hoc Network (VANET) is a network formed purely among vehicles without presence of any
communication infrastructure as base stations and/or access point. Frequent topological changes due to
high mobility is one of the main issues in VANETs. In this paper we evaluate Ad-hoc On-Demand Distance
Vector (AODV) and Optimized Link State Routing (OLSR) routing protocols using 802.11a and 802.11p in
a realistic urban scenario. For this comparison, we chose five performance metrics: Path Availability, Endto-
End Delay, Number of Created Paths, Path Length and Path Duration. Simulation results show, that for
most of the metrics evaluated, OLSR outperforms AODV when 802.11p and that 802.11p is more efficient
in urban VANETs.
This document discusses adjacent channel interference (ACI) and its impact on the capacity of WCDMA/FDD networks. It describes simulations performed to study ACI under different scenarios and network configurations. The key findings are that the macro carrier should be placed in the center of the frequency band to be protected from ACI, as it suffers the greatest losses. Meanwhile, the micro carrier should be placed as close as possible to adjacent channels to maximize capacity. Proper frequency planning is important for optimizing network performance in the presence of ACI.
PERFORMANCES OF ORTHOGONAL WAVELET DIVISION MULTIPLEX (OWDM) SYSTEM UNDER AWG...IJCNCJournal
Orthogonal Wavelet Division Multiplexing (OWDM) has been considered as an alternative of Orthogonal
Frequency Division Multiplexing (OFDM) in the recent years. OWDM has lower computational complexity
and higher flexibility compared to its OFDM counterpart. The core component of OWDM is wavelet.
Wavelet has been a much investigated and applied topic in digital image processing for a long time.
Recently, it has drawn considerable attention of the researchers working in communication field. In this
work we investigate the performances of OWDM under different channel conditions. We consider three
channel conditions namely Additive White Gaussian Noise (AWGN), Rayleigh, Ricean, and frequency
selective. We consider a number of wavelets namely Haar, Daubechies, Biorthogonal, Reverse
Biorthogonal, Coiflets, and Symlets in OWDM design. For system model we choose Digital Video
Broadcasting-Terrestrial (DVB-T). Originally DVB-T system was designed based on OFDM. In this work
we use OWDM instead. The simulation results show OWDM outperforms OFDM in terms of bit error rate
(BER), noise resiliency, and peak-to-average ration. The results also show that the Haar wavelet based
OWDM outperforms other wavelets based OWDM system under all three considered three channel
conditions.
IRJET-Analysis of Medium Access Protocols with Channel Bonding for Cognitive ...IRJET Journal
This document analyzes the performance of medium access control (MAC) protocols with channel bonding for cognitive radio networks operating on television (TV) bands. It studies the slotted ALOHA and non-persistent CSMA MAC protocols using two orthogonal frequency-division multiplexing (OFDM) schemes: fixed-carrier number (FCN) and fixed-carrier spacing (FCS). The document presents an analytical model for throughput estimation and simulations of the MAC protocols with FCN and FCS OFDM on different TV channel widths. The results show that the non-persistent CSMA protocol achieves better performance than slotted ALOHA, and that channel capture effects are significant.
Improvement of crankshaft MAC protocol for wireless sensor networks: a simula...IJECEIAES
Due to the dramatic growth in the use of Wireless Sensor Network (WSN) applications ranging from environment and habitat monitoring to tracking and surveillance, network research in WSN protocols has been very active in the last decade. With battery-powered sensors operating in unattended environments, energy conservation becomes the key technique for improving WSN lifetimes. WSN Medium Access Control (MAC) protocols address energy awareness and reduced duty cycles. The focus of this study is to investigate, through simulation, the effect of variations in various factors that influence the performance results of WSNs. Using MiXiM framework with OMNeT++ simulator, this simulation study proposes modifications in Crankshaft MAC protocol in order to improve its performance. The impact of duration and number of slots, degree of connectivity among the nodes, mobility speed and mobility update interval and also, the impact of sending data packets without preambles are investigated. Based on the simulation results, an improved version of the Crankshaft protocol for WSN is suggested and a comparative study of the performances of the original and improved protocol is presented. The results clearly indicate the superiority of the improved protocol over its original version.
A SEMI BLIND CHANNEL ESTIMATION METHOD BASED ON HYBRID NEURAL NETWORKS FOR UP...ijwmn
The paper describes how to improve channel estimation in Single Carrier Frequency Division Multiple
Access (SC-FDMA) system, using a Hybrid Artificial Neural Networks (HANN). The 3rd Generation
Partnership Project (3GPP) standards for uplink Long Term Evolution Advanced (LTE-A) uses pilot based
channel estimation technique. This kind of channel estimation method suffers from a considerable loss
ofbitrate due to pilot insertion; all data frame sent contains reference signal. The HANN converts data
aided channel estimator to semi blind channel estimator. To increase convergence speed, HANN uses some
channel propagation Fuzzy Rules to initialize Neural Network parameters before learning instead of a
random initialization, so its learning phase ismore rapidly compared to classic ANN.HANN allows more
bandwidth efficient and less complexity. Simulation results show that HANN has better computational
efficiency than the Minimum Mean Square Error (MMSE) estimator and has faster convergence than
classic Neural Networks estimators.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Mobile Ad hoc Networks (MANETs) are characterized by open structure, lack of standard infrastructure
and un-accessibility to the trusted servers. The performance of various MANET routing protocols is
significantly affected due to frequently changing network topology, confined network resources and
security of data packets. In this paper, a simulation based performance comparison of one of the most
commonly used on-demand application oriented routing protocols, AODV (Ad hoc on-demand Distance
Vector) and its optimized versions R-AODV (Reverse AODV) and PHR-AODV (Path hopping based
Reverse AODV) has been presented. Basically the paper evaluates these protocols based on a wide set of
performance metrics by varying both the number of nodes and the nodes maximum speed. A NS-2 based
simulation study shows that, as compared to AODV and PHR-AODV, R-AODV enhances the packet
delivery fraction by 15-20% and reduces the latency approximately by 50%. R-AODV requires lesser node
energy for data transmission.
During route discovery of mobile ad hoc network, broadcasting of route request and route reply packets
are the essential operations for finding the path between two ends. In such situations, intermediate node
which may or may not belongs will participate in route discovery process, update routing table and
rebroadcast the route discovery packets again to its neighboring nodes. Finally optimal path is found with
minimum hops. This simply upsurges overhead and deteriorates the performance of routing. The proposed
Petal Ant Routing (PAR) algorithm offers a low overhead by optimizing FANT and BANT transmissions in
route discover process. The algorithm is an improved version of SARA and has features extracted from
petal routing. The algorithm is simulated on NS2, compared with ACO frame work called SARA and
classical routing protocols such as AODV and AOMDV. The simulation results shows that PAR further
reduces overhead by eliminating redundant FANT transmission compared to other routing algorithm.
Optical Burst Switching (OBS) is a data
switching technique for upcoming computer networks,
since this technique can perform data switching and
data processing operations with high speed and
efficiency. Its main goal is to get rid of problems found
in two main techniques, which are, Optical Circuit
Switching (OCS) and Optical Packet Switching (OPS).
Routing deflection methods route bursts to other output
ports, in fact it is not intended to resolve contention. In
OBS, when burst is not programmed on other output
port through routing deflection then it is simply deleted.
To route data to the receiver, the routing deflection does
not resolve all aspects that resulted loss of data;
therefore, the performance of schemes deflection
existence is not acceptable by the systems and so it
closes with deletion any plan to resolving contention,
backtrack if deflection fails (BDF), that is given as a
second opportunity to burst in order to face the failure
through deflection, the blocked bursts will return to the
previous station, to find suitable alternative available
paths.
Enhancing performance using TOHIP in MANETIJTET Journal
Abstract— Mobile Ad hoc Network (MANET) is a special self-describing wireless ad hoc network which consists of additional number of nodes that can move randomly and erratically. Due to this infrastructure it enables numerous kinds of attacks and establish topology-exposure problem. Many of the existing multipath protocols may ignore the topology-exposure problem. In this, we proposed a TOpology-HIding multipath routing Protocol (TOHIP) for preventing attacks in topology-exposure. In TOHIP, the link connection information is hidden in route messages, so that the malicious nodes cannot conclude the network topology. In Route Reply phase, the protocol TOHIP can also be used to establish multiple node-disjoint routes and eliminate the unreliable route before transmitting packets in Route Probe phase. With facilitate of a newly designed protocol, security was assured and earned superior capability of finding routes in MANET. The simulation result shows that TOHIP has given recovered performance when compared with Ad hoc On-demand Multipath Distance Vector (AOMDV) routing protocol.
This document summarizes a study that compares different methods for estimating the power delay profile (PDP) in MIMO-OFDM systems. It proposes a new method for PDP estimation that aims to mitigate noise and improve accuracy with limited sample sizes. The key steps of the proposed method are: 1) estimating the channel impulse response from pilot subcarriers, 2) deriving samples from the estimated channel response to estimate the PDP, 3) mitigating residual noise in the estimate by detecting and averaging noise at zero taps, and 4) using the estimated PDP in an LMMSE channel estimator. Simulation results show that the proposed method approaches the performance of Wiener filtering and provides better SNR than using a constant PDP estimate
11.a study of congestion aware adaptive routing protocols in manetAlexander Decker
This document summarizes and compares several congestion-aware routing protocols for mobile ad hoc networks (MANETs). It discusses the Congestion Adaptive Routing Protocol (CRP), which uses bypass routes to avoid congested areas and splits traffic between primary and bypass routes adaptively. It also describes the Efficient Congestion Adaptive Routing Protocol (ECARP), which modifies AODV parameters to improve congestion handling, and the Congestion Aware Routing plus Rate Adaptation (CARA) protocol, which establishes routes around congested areas. Finally, it discusses the Congestion Aware Routing Protocol for Mobile ad hoc networks (CARM), which uses a weighted channel delay metric to measure
The document summarizes Tranzeo's TR-WMX-3.5-17 3.5GHz Outdoor Subscriber Unit, which is part of their family of low-cost subscriber units that adhere to the IEEE 802.16-2004 WiMAX standard. The outdoor unit has a 17dBi antenna, supports data rates up to 35 Mbps, and is designed for easy customer installation with signal strength LEDs. Tranzeo manufactures the unit to provide the lowest price with the highest quality and a three year warranty.
The TR-WMX-5.8-pBS is a pico base station that adheres to IEEE 802.16-2004 WiMAX standards and provides wireless broadband connectivity for outdoor applications. It is part of Tranzeo's comprehensive WiMAX product family and offers a turn-key solution for last-mile communication. The pico base station has a low-cost design, high quality, and ease of installation to ensure low deployment costs. It is managed by Tranzeo's advanced Element Management System to allow for remote upgrades and software management.
The TR-WMX-3.5-pBS pico Base Station is a WiMAX product that:
1) Adheres to IEEE 802.16-2004 standards and is based on Wavesat products, providing a comprehensive WiMAX product family.
2) Offers future-proof features like remote software management and is Airsync-ready for autonomous QoS and real-time provisioning.
3) Has a low-cost design, high quality, and ease of installation making it suitable for incremental network build-outs and guaranteed high-bandwidth applications.
The document provides instructions for installing the Tranzeo TR-5A wireless access point, including:
1) A list of included hardware components and safety notices for installation.
2) Directions for selecting an installation site and orienting the device horizontally or vertically.
3) Steps for connecting an Ethernet cable to the device using an Ethernet boot and cable lock to protect the connection from moisture.
The document is a user guide for the Tranzeo TR-5A series of wireless radios, covering models TR-5a-20 through TR-5amp-N. It contains information on safety, hardware installation including mounting, grounding and connecting the radio, and configuring the wireless, administrative, security and other settings through the radio's web-based interface. Professional installation is required due to safety regulations.
This document provides an overview of key considerations for setting up a wireless ISP (WISP). It discusses Tranzeo Wireless as a vendor, emphasizing their support, reliable products, and helping customers design cost-effective solutions. Several technical aspects are covered, such as choosing the right equipment, conducting site surveys, managing bandwidth, and ensuring reliable connections. The document stresses that every location has unique needs, and finding the right vendor is important to receiving proper guidance on planning and optimizing a WISP network.
The document describes several point-to-point wireless backhaul solutions for distances between 5 to over 20 miles. The TR-5821 solution includes a 40dBm radio, 21dB antenna, and mounting bracket for a 5 mile range. The TR-5826, TR-5829, and TR-5832 solutions include higher gain external antennas - 26dBi, 29dBi, and 32dBi grids and dishes respectively - for ranges of 10, 20, and extended miles along with an enclosure and cable. All solutions include power over ethernet and operate in the 5GHz band.
Tranzeo is announcing their new TR-5plus Series of 5.3/5.4/5.8 GHz radios. These all-in-one units can be configured as an access point, point-to-point bridge, or client adapter. They have a high gain output of +23dBm, dual Ethernet ports, support for tunneling protocols, and low power requirements of only 7 watts. The radios also have new features such as wireless distribution system, WPA encryption, alignment LEDs, and IP-based remote management.
Tranzeo has announced a new TR-5amp series of 5GHz radios that can function as an access point, point-to-point bridge, or client adapter. The radios have dual Ethernet ports, support for tunneling protocols like VPN, and security features including WPA and WEP. They also have alignment LEDs, adjustable transmit power, and high gain external antenna options up to 32dBi.
Point to point (PxP) applications are used to connect two locations over wireless. They act as a bridge to carry a signal from point A to point B, such as providing internet access to a remote area. To set up a PxP link using Tranzeo equipment, the first unit at the source location is configured as an access point, while the second unit at the remote location is configured as a client infrastructure connected in bridge mode. Both units must have their PxP mode enabled and configured with each other's MAC address to isolate the connection between just the two units.
This document summarizes a research paper on the development of a prototype hybrid wireless-optical broadband access network (WOBAN). Key points:
1) Researchers at UC Davis built a WOBAN prototype combining an optical Ethernet PON backend with an IEEE 802.11g wireless mesh frontend to test the architecture.
2) The prototype has programmable wireless routers and OLT/ONU units to experiment with control, data, and management planes.
3) Experimental results show the prototype is able to support various applications like data, VoIP, and video streaming through the integrated wireless-optical network.
The document summarizes the hybrid wireless-optical broadband-access network (WOBAN) architecture. It discusses how WOBAN combines the benefits of wireless and optical networks by using an optical network like a passive optical network (PON) at the back end connected to wireless base stations. This saves on network deployment costs compared to fully wired networks. The document then reviews challenges for WOBAN including algorithms for network setup and placement of optical network units, examining the network's routing properties, and designing fault-tolerant behavior. It provides context on industry efforts to deploy related broadband access solutions and municipal mesh networks.
This document proposes and analyzes a model for planning hybrid wireless-optical broadband access networks (WOBANs). A WOBAN combines the reliability of fiber optic networks with the flexibility of wireless networks. The document presents a primal model for optimally placing base stations and optical network units in a WOBAN. It develops constraints for user assignment, capacity, interference and develops a Lagrangean relaxation approach and primal algorithm to obtain upper and lower bounds for the solution to the primal model. Simulation results are used to compare the primal model to a cellular heuristic placement approach.
This document is a full text paper that was peer reviewed for publication in the ICC 2007 proceedings. It proposes a Delay-Aware Routing Algorithm (DARA) for minimizing average packet delay in the wireless front end of a hybrid wireless-optical broadband access network (WOBAN). DARA models wireless routers as queues, predicts wireless link states periodically, and assigns link weights based on predicted delay to compute the minimum delay path for packets traveling through the wireless mesh network to gateways.
The document proposes techniques to build green broadband access networks called Wireless-Optical Broadband Access Networks (WOBAN) that reduce energy consumption. It develops energy-aware design techniques and routing protocols for WOBAN. A Mixed Integer Linear Program model is used to analyze the impact of energy-aware design on WOBAN's performance. Results show large potential power savings from incorporating energy-aware design and routing in access networks.
This document is a dissertation submitted by Suman Sarkar for the degree of Doctor of Philosophy in Computer Science at the University of California, Davis in 2008. The dissertation proposes a novel hybrid network architecture called Wireless-Optical Broadband Access Network (WOBAN) that combines high-capacity optical access with untethered wireless access. The dissertation investigates design algorithms, network protocols, and business drivers for WOBAN. It develops heuristics like greedy algorithm and simulated annealing for network planning and setup. It also explores a constraint programming model and develops routing algorithms that consider delay and fault tolerance for WOBAN connectivity.
This document summarizes an experiment on a radio-over-fiber system for hybrid wireless-optical broadband access networks. The system used 5 GHz radio frequency signals transmitted over a 60 km fiber link using 12.5 GHz dense wavelength division multiplexing with 5 channels. Digital coherent detection and Raman amplification were used to provide enhanced power budget and reach. Bit error rate measurements showed error-free transmission was achieved after the 60 km link with and without neighboring channel interference, demonstrating the feasibility of the system for long-reach hybrid wireless-optical networks.
This document discusses multi-radio hybrid wireless-optical broadband access networks (WOBANs). It describes how WOBANs combine optical and wireless networks, with fiber providing long-distance connectivity to the central office and wireless providing local access. Equipping mesh routers in the wireless front-end with multiple radios tuned to non-overlapping channels can improve network throughput by allowing more simultaneous transmissions. However, properly assigning channels to radios is challenging. The document proposes addressing integrated routing and channel assignment in multi-radio WOBANs to evaluate how throughput can be increased by using multiple radios per router and optimally distributing radios across the network.
This document discusses enhancing the capacity of the wireless portion of a hybrid wireless-optical broadband access network (WOBAN) through the strategic placement of additional radios at bottleneck nodes. Deploying multiple radios at every node improves performance but increases costs. The document proposes formulating the problem of optimally placing a limited number of additional radios as an integer linear program to maximize performance while minimizing costs. Prior work on routing, capacity assignment, and radio placement in wireless mesh networks is reviewed. The impact of deploying multiple radios only at overloaded bottleneck nodes is studied through numerical examples.
1) Wavelength shifters are fluorescent chemicals that can absorb ultraviolet Cherenkov photons and re-emit them at longer wavelengths detectable by photomultiplier tubes, improving light yield.
2) The document studies potential wavelength shifters for use in the Sudbury Neutrino Observatory heavy water Cherenkov detector to increase detection efficiency.
3) It tests several water-soluble wavelength shifter candidates, measuring their optical properties, stability, and compatibility with detector materials to find suitable options for deploying in the detector to boost the Cherenkov signal.
2. both PONs and WMNs. Therefore, the topology of routing layer may be different from physical topology. The
shortest path in routing layer may not be the best choice from physical topology point of view. In this paper, we
motivate the needs of considering availability in routing decisions. Availability is the probability that the connection
will be found in the operating state at a random time in the future [7]. It is affected by many factors, such as network
component failure probabilities, failure repair times, etc. There are basically two motivations for us to study
availability-aware routing for large-scale hybrid WOBAN: 1) It is well known that the availability of optical links and
wireless links varies significantly, so routes along different links may have very different availability and thus affect
the stability of services; and 2) Availability is an important parameter in Service Level Agreement (SLA) between a
network operator and network service subscribers, so it is necessary to have an availability-aware routing to minimize
availability along the route or at least avoid highly unstable routes. Obviously, the main challenge of
availability-aware routing for large-scale hybrid WOBAN is that routing will not only be calculated purely based on
routing layer topology, but also need to consider physical constraints, e.g. availability of components and segment of
links (for example, availability of fiber from Optical Line Terminal ( OLT) 1 to Splitter E in Fig. 1(a)).
2. The proposed availability-aware routing for large-scale hybrid WOBN
If we know the mean time to failure (MTTF) and mean time to repair (MTTR) of a component, link, or connection, its
availability can be calculated as
a = MTTF / (MTTF + MTTR ) (1)
Let ai denote the availability of link i along a path. The availability of path k can be calculated as
Ak = ∏i∈P ai k
(2)
For example, as shown in Fig. 1(a), the availability of fiber from OLT 1 to Splitter E is 0.99, the availability of fiber
from Splitter E to Splitter B is 0.97, and the availability of fiber from Splitter B to Gateway/ONU 3 is 0.98. Using
Equation (2), the availability of the optical link from node 1 to node 3 is calculated as 0.99×0.98×0.97=0.9411, as
shown in Fig. 1(b). To calculate the most available path with the shortest-path (SP) algorithm, e.g. Dijkstra's
algorithm, we can use
− log( Ak ) = − log(a1 ) + L − log(a P ) (3)
In other words, using Equation (3), we can add weights on links of networks, and thus apply the shortest-path
algorithm for computing the most available path. Note that the most available path (MAP) is defined as a path with the
highest availability from the source to the destination of a connection request. The most available path will be equal to
the shortest path provided the availability of each link is the same. For example, using Equation (3), we can calculate
that the route 13-10-4-1 is 0.8206 and route 13-3-1 is 0.8092. Apparently, the most available path from node 13 to
node 1 is 13-10-4-1 while 13-3-1 is the shortest path.
Table 1. Comparison under empty 25-node SFNet.
Distribution 14-node 25-node
of link Parameters topology topology
availability AAR SPR AAR SPR
0.9 < ai < 1 Average hops 2.535 2.049 3.234 2.627
Average availability 0.927 0.904 0.924 0.879
Improvement over SPR 2.5% N.A. 5.1% N.A.
0.7 < a i < 1 Average hops 3.048 2.044 3.546 2.634
Average availability 0.769 0.701 0.783 0.670
Improvement over SPR 9.7% N.A. 14.4% N.A.
Fig. 2. Routing layer topology of 25-node SFNet.
3. Simulation results and discussions
We first use the 14-node topology, as shown in Fig. 1, and then a much larger network, i.e., the 25-node SFNet in San
Francisco city area[2], [4], as shown in Fig. 2, under different link availability parameters. The availability of link is
uniformly distributed from 0.9 to 1, i.e., 0.9 < ai < 1 and from 0.7 to 1, i.e., 0.7 < a i < 1 . The simulation program was
written with Matlab and the final result is the average of at least 30,000 connection requests. An arrival request is
equally likely to be arrived at and destined to any node in the network. First, we compare the availability-aware
routing (AAR) and the shortest-path routing (SPR) under empty networks, i.e., routing is totally based on network
topology without considering traffic distribution. Simulation results in table 1 show, as expected, AAR is less capacity
efficient than SPR, and AAR steadily outperforms SPR in average availability with the increase of variation of link
3. availability.
Second, consider the scenario of different traffic distributions on the network. For simplification, assume every link
has the same capacity and one connection request over a link will consume one capacity of the link. For dynamic
traffic, the arrival of traffic to the network follows Poisson distribution with rate λ connection requests per unit time
and connection-holding time is exponentially distributed with a mean value of one unit time. We use dynamic routing,
where the shortest path or most available path is calculated according to current network states. Due to limited
resource, some connection request may be rejected if the path cannot be found. Blocking probability is defined as the
number of rejected connection requests against the total number of connection requests. Fig. 3 - Fig. 4 plot simulation
results. Fig. 3(a) and Fig. 4(a) show that SPR always has the lowest blocking probability due to its capacity efficiency,
Fig. 3(b) and Fig. 4(b) show that AAR will use more hops than SPR does, and, furthermore, Fig. 3(c) and Fig. 4(c)
demonstrate that the average availability of AAR is much better than that of SPR especially when load is low.
0.915
0.035 2.4
AAR
AAR
AAR 2.35 SPR
0.03 SPR 0.91
SPR
2.3
Average Availability
0.025
Blocking Probability
Average Hops
2.25 0.905
0.02
2.2
0.015 0.9
2.15
0.01
2.1
0.895
0.005 2.05
0 2 0.89
6 12 18 24 6 12 18 24 6 12 18 24
Network Load in Erlang Network Load in Erlang Network Load in Erlang
Fig. 3. Simulation results (14-node topology, 0.9 < a i < 1 , and capacity per link is 10)
0.04 3.6 0.94
AAR AAR AAR
0.035 0.93 SPR
SPR SPR
3.4
0.03 Average Availability
Blocking Probability
0.92
Average Hops
0.025 3.2
0.02 0.91
0.015 3
0.9
0.01
2.8
0.89
0.005
0 2.6 0.88
8 16 24 32 40 8 16 24 32 40 8 16 24 32 40
Network Load in Erlang Network Load in Erlang Network Load in Erlang
Fig. 4. Simulation results (25-node SFNet, 0.9 < a i < 1 , and capacity per link is 10)
4. Conclusion
In large-scale hybrid WOBAN, the availability of optical links and wireless links varies significantly. Traditional
availability-unaware routing using the shortest path will lead to bad performance of path availability.
Availability-aware routing can significantly improve availability and throughput by encouraging more usage of PON.
5. References
[1] S. Sarkar, H. H. Yen, S. Dixit, and B. Mukherjee, “ A novel delay-aware routing algorithm (DARA) for a hybrid wireless-optical broadband
access network (WOBAN),” IEEE Network, Vol. 22, Issue 3, May-June 2008, pp. 20-28.
[2] S. Sarkar, S. Dixit, and B. Mukherjee, “Hybrid wireless-optical broadband access network (WOBAN): A review of relevant challenges,” J. of
Lightwave Technol., vol. 25, no. 11, pp. 3329-3340, Nov. 2007.
[3] A. S. Reaz, V. Ramamurthi, S. Sarkar, D. Ghosal, S. Dixit, and B. Mukherjee, “CaDAR: an efficient routing algorithm for wireless-optical
broadband access network,” in Proc., IEEE ICC’08, May 2008, pp. 5191-5195.
[4] S. Sarkar, H. H. Yen, S. Dixit, and B. Mukherjee, “DARA: delay-aware routing algorithm in a hybrid wireless-optical broadband access
network (WOBAN),” in Proc., IEEE ICC '07, June 2007.
[5] W. T. Shaw, S. W. Wong, N. Cheng, K. Balasubramaian, C. Qiao, and L. G. Kazovsky, “Reconfigurable optical backhaul and integrated
routing algorithm for load balancing in hybrid optical-wireless access networks", in Proc., IEEE ICC’08, May 2008, pp. 5697–5701.
[6] W. T. Shaw, S. W. Wong, N. Cheng, K. Balasubramanian, X. Zhu, M. Maier, and L. G. Kazovsky, “Hybrid architecture and integrated routing
in a scalable optical–wireless access network,” J. of Lightwave Technol., Vol. 25, Issue 11, Nov. 2007, pp. 3443-3451.
[7] J. Zhang, K. Zhu, H. Zang, N. S. Matloff, and B. Mukherjee, “Availability-aware provisioning strategies for differentiated protection services
in wavelength-convertible WDM mesh networks.” IEEE/ACM Trans. Netw., vol. 15, pp. 1177-1190, Oct. 2007.