The document analyzes the signal-to-interference-noise ratio (SINR) performance of two beamforming methods, complex conjugate (CC) and direction-of-arrival (DOA), used in Wideband Code Division Multiple Access (W-CDMA) smart antenna systems. It derives analytic SINR evaluation equations for both methods under different channel conditions. The results show that the CC and DOA methods provide the same mean SINR performance but the CC method is more robust to channel estimation errors. Simulation results are presented to verify the analytic performance and robustness analyses.
Filter Bank-based Multicarrier Modulation (FBMC) using Offset Quadrature
Amplitude Modulation (OQAM), known as FBMC/OQAM (or OFDM/OQAM), provides an
attractive alternative to the conventional Cyclic Prefix-Based Orthogonal Frequency
Division Multiplexing (CP-OFDM), especially in terms of increased robustness to frequency
offset and Doppler spread, and high bandwidth efficiency. It suffers, however, from an
inherent (intrinsic) imaginary Intercarrier/Inter-symbol interference that complicates signal
processing tasks such as Channel Estimation (CE). Recently, the so-called Interference
Approximation Method (IAM) was proposed for preamble-based CE. It relies on the
knowledge of the pilot's neighbourhood to approximate this interference and constructively
exploit it in simplifying CE and improving its performance. The IAM preamble with nulls at
the neigh boring time instants and extended version of it, which can provide significant
improvement through an appropriate exploitation of the interfering symbols from
neighbouring time instants that results in CE performance was recently reported. In this
paper, we present IAM preamble design and apply it to identify the optimal IAM preamble
sequence which results in a higher gain. Numerical results have verified the effectiveness of
the theoretical framework and a gain of 1.24 dB against E-IAM-C.
A blind channel shortening for multiuser, multicarrier CDMA system over multi...TELKOMNIKA JOURNAL
In this paper we derive the Multicarrier Equalization by Restoration of Redundancy (MERRY) algorithm: A blind, adaptive channel shortening algorithm for updating a Time-domain Equalizer (TEQ) in a system employing MultiCarrier Code Division Multiple Access (MC-CDMA) modulation. We show that the MERRY algorithm applied to the MC-CDMA system converges considerably more rapidly than in the Orthogonal Frequency Division Multiplexing (OFDM) system [1]. Simulations results are provided to demonstrate the performance of the algorithm.
A novel and efficient mixed-signal compressed sensing for wide-band cognitive...Polytechnique Montreal
In cognitive radio (CR) networks, unlicensed (cognitive) users can exploit the licensed frequency bands by using spectrum sensing techniques to identify spectrum holes. This paper proposes a distributed compressive spectrum sensing scheme, in which the modulated wide-band converter can apply compressed sensing (CS) directly to analog signals at the sub-Nyquist rate and the central fusion receives signals from multiple CRs and exploits the multiple-measurements-vectors (MMV) subspace pursuit (M-SP) algorithm to jointly reconstruct the spectral support of the wide-band signal. This support is then used to detect whether the licensed bands are occupy or not. Finally, extensive simulation results show the advantages of the proposed scheme. Besides, we also compare the performance of M-SP with M-orthogonal matching pursuit (M-OMP) algorithms.
EE402B Radio Systems and Personal Communication Networks notesHaris Hassan
Programmes in which available:
Masters of Engineering - Electrical and Electronic
Engineering. Masters of Engineering - Electronic
Engineering and Computer Science. Master of Science -
Communication Systems and Wireless Networking.
Master of Science - Smart Telecom and Sensing
Networks. Master of Science - Photonic Integrated
Circuits, Sensors and Networks.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
On Channel Estimation of OFDM-BPSK and -QPSK over Nakagami-m Fading ChannelsCSCJournals
This paper evaluates the performance of OFDM - BPSK & -QPSK based system with and without channel estimation over Nakagami-m fading channels. Nakagami-m variants are generated by decomposition of Nakagami random variable into orthogonal random variables with Gaussian distribution envelopes. Performance of OFDM system in Nakagami channel has been reported here. The results yield the optimum value of m based on BER and SNR. Using this optimum value of m, Channel estimation over flat fading has been reported here. It has been depicted clearly from simulated graphs that channel estimation has further reduced the BER. However, threshold value of m has played a vital role during channel estimation.
Filter Bank-based Multicarrier Modulation (FBMC) using Offset Quadrature
Amplitude Modulation (OQAM), known as FBMC/OQAM (or OFDM/OQAM), provides an
attractive alternative to the conventional Cyclic Prefix-Based Orthogonal Frequency
Division Multiplexing (CP-OFDM), especially in terms of increased robustness to frequency
offset and Doppler spread, and high bandwidth efficiency. It suffers, however, from an
inherent (intrinsic) imaginary Intercarrier/Inter-symbol interference that complicates signal
processing tasks such as Channel Estimation (CE). Recently, the so-called Interference
Approximation Method (IAM) was proposed for preamble-based CE. It relies on the
knowledge of the pilot's neighbourhood to approximate this interference and constructively
exploit it in simplifying CE and improving its performance. The IAM preamble with nulls at
the neigh boring time instants and extended version of it, which can provide significant
improvement through an appropriate exploitation of the interfering symbols from
neighbouring time instants that results in CE performance was recently reported. In this
paper, we present IAM preamble design and apply it to identify the optimal IAM preamble
sequence which results in a higher gain. Numerical results have verified the effectiveness of
the theoretical framework and a gain of 1.24 dB against E-IAM-C.
A blind channel shortening for multiuser, multicarrier CDMA system over multi...TELKOMNIKA JOURNAL
In this paper we derive the Multicarrier Equalization by Restoration of Redundancy (MERRY) algorithm: A blind, adaptive channel shortening algorithm for updating a Time-domain Equalizer (TEQ) in a system employing MultiCarrier Code Division Multiple Access (MC-CDMA) modulation. We show that the MERRY algorithm applied to the MC-CDMA system converges considerably more rapidly than in the Orthogonal Frequency Division Multiplexing (OFDM) system [1]. Simulations results are provided to demonstrate the performance of the algorithm.
A novel and efficient mixed-signal compressed sensing for wide-band cognitive...Polytechnique Montreal
In cognitive radio (CR) networks, unlicensed (cognitive) users can exploit the licensed frequency bands by using spectrum sensing techniques to identify spectrum holes. This paper proposes a distributed compressive spectrum sensing scheme, in which the modulated wide-band converter can apply compressed sensing (CS) directly to analog signals at the sub-Nyquist rate and the central fusion receives signals from multiple CRs and exploits the multiple-measurements-vectors (MMV) subspace pursuit (M-SP) algorithm to jointly reconstruct the spectral support of the wide-band signal. This support is then used to detect whether the licensed bands are occupy or not. Finally, extensive simulation results show the advantages of the proposed scheme. Besides, we also compare the performance of M-SP with M-orthogonal matching pursuit (M-OMP) algorithms.
EE402B Radio Systems and Personal Communication Networks notesHaris Hassan
Programmes in which available:
Masters of Engineering - Electrical and Electronic
Engineering. Masters of Engineering - Electronic
Engineering and Computer Science. Master of Science -
Communication Systems and Wireless Networking.
Master of Science - Smart Telecom and Sensing
Networks. Master of Science - Photonic Integrated
Circuits, Sensors and Networks.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
On Channel Estimation of OFDM-BPSK and -QPSK over Nakagami-m Fading ChannelsCSCJournals
This paper evaluates the performance of OFDM - BPSK & -QPSK based system with and without channel estimation over Nakagami-m fading channels. Nakagami-m variants are generated by decomposition of Nakagami random variable into orthogonal random variables with Gaussian distribution envelopes. Performance of OFDM system in Nakagami channel has been reported here. The results yield the optimum value of m based on BER and SNR. Using this optimum value of m, Channel estimation over flat fading has been reported here. It has been depicted clearly from simulated graphs that channel estimation has further reduced the BER. However, threshold value of m has played a vital role during channel estimation.
In this paper, three beamforming design are considered for multi user MIMO system. First, transmit
beamformers are fixed and the receive (RX) beamformers are calculated. Transmit beamformer (TX-BF)is
projectedas a null space of appropriate channels. It reduces the interference for each user. Then the receiver
beamformer is determined which maximize the SNR. This beamforming design provides less computation time.
The second case is joint TX and RX beamformer for SNR maximization. In this transmitter and receiver
beamformer are calculated using extended alternating optimization (EAO) algorithm. The third one is joint
transmitter and receiver beamforming for SNR and SINR maximization using EAO algorithm. This algorithm
provides better error performance and sum rate performance. All the design cases are simulated by using
standard multipath channel model. Our simulation results illustrate that compared to the least square design and
zero forcing design, the joint TX and RX beamforming design using EAO algorithm provides faster
beamforming and improved error performance and sum rate.
Classical Discrete-Time Fourier TransformBased Channel Estimation for MIMO-OF...IJCSEA Journal
In this document, we look at various time domain channel estimation methods with this constraint of null carriers at spectrumborders.We showin detail howto gauge the importance of the “border effect” depending on the number of null carriers, which may vary from one system to another. Thereby we assess the limit of the technique discussed when the number of null carriers is large. Finally the DFT with the truncated singular value decomposition (SVD) technique is proposed to completely eliminate the impact of the null subcarriers whatever their number. A technique for the determination of the truncation threshold for any MIMO-OFDM system is also proposed.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
Performance Analysis of PAPR Reduction in MIMO-OFDMIJARBEST JOURNAL
Authors: Jayaraman.G1, VeeraKumar K2, Selvakani.S3
Abstract— In communication system, it is aimed to provide highest possible
transmission rate at the lowest possible power and with the least possible noise. MIMOOFDM
has been chosen for high data rate communications and widely deployed in many
wireless communication standards. The major drawback in OFDM signal transmission is
high PAPR. In previous, use clipping technique to tackle this problem. In this paper, use
EM-GAMP algorithm to reduce PAPR in considerable amount.
3D METALLIC PLATE LENS ANTENNA BASED BEAMSPACE CHANNEL ESTIMATION TECHNIQUE F...ijwmn
Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna
system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of
information from mobile devices. However, this estimation is required to ensure the perfect channel state
information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase
shifter (PS) components used in this estimation need high power to select the beam in the desired direction.
To overcome these limitations, in this work, we propose Regular Scanning Support Detection (RSSD)
based channel estimation mechanism. Moreover, we utilise a 3D lens antenna array having metallic plate
and a switch in our model which compensates the limitation of phase shifters. Simulation results show that
the proposed RSSD based channel estimation surpasses traditional technique and SD based channel
estimation even in lower SNR area which is highly desirable in the millimeter wave (mmWave) massive
MIMO systems.
Multi carrier equalization by restoration of redundanc y (merry) for adaptive...IJNSA Journal
This paper proposes a new blind adaptive channel shortening approach for multi-carrier systems. The
performance of the discrete Fourier transform-DMT (DFT-DMT) system is investigated with the proposed
DST-DMT system over the standard carrier serving area (CSA) loop1. Enhanced bit rates demonstrated
and less complexity also involved by the simulation of the DST-DMT system.
Orthogonal Frequency Division Multiplexing (OFDM) is deployed to overcome the interference. However,
OFDM has a relatively large OOB emissions. In spectrum sharing approaches such as dynamic spectrum
access networks, the OOB power levels of secondary transmissions should be kept below a certain level, in
order not to interfere with primary transmissions. . The difficulties such as sidelobes and PAPR caused by
OFDM is reduced by convex optimization and PTS technique respectively. In this technique each OFDM
subcarrier is multiplied with a real-valued weight that is determined in order not to interfere with adjacent
users. The problem with the SW technique is involving a very complex optimization. We propose a heuristic
approach called convex optimization. It can achieve considerable sidelobe suppression while requiring
significantly less computational resources than the optimal solution. Implementation results prove that it
can be introduced for real-time transmissions. Optimizing the subcarrier weights and SINR is complex, for
which we use the technique of convex optimization. For reducing the PAPR we use Partial Transmit
Sequence (PTS) technique.
Index terms : OFDM (Orthogonal Frequency Division Multiplexing), PAPR (Peak Average Power
Ratio), OOB (Out Of Band), IFFT (Inverse Fast Fourier Transform).
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.
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
A new look on CSI imperfection in downlink NOMA systemsjournalBEEI
Observing that cooperative scheme benefits to non-orthogonal multiple access (NOMA) systems, we focus on system performance analysis of downlink. However, spectrum efficiency is still high priority to be addressed in existing systems and hence this paper presents full-duplex enabling in NOMA systems. Other challenge needs be considered related to channel state information (CSI). In particular, we derive closedform expressions of outage probability for such NOMA systems under the presence of CSI imperfection. Furthermore, to fully exploit practical environment, we provide system model associated with Nakagami-m fading. The Monte-Carlo simulations are conducted to verify the exactness of considered systems.
Design and Fabrication of a Two Axis Parabolic Solar Dish CollectorIJERA Editor
The work consists of the design of the chain drive system and the fabrication of the two axis parabolic solar dish.
It is a model study of the two axis parabolic dish which worked by the automatic circuit that was developed. Ready
made parabolic solar dish is taken and fabricated. The circular iron ring provides the two axis motion of the dish.
A compound chain drive system was developed for the smooth movement of the dish. An electromechanical
system which tracks the sun on both axes and which is controlled via a programmable logic control (PLC) was
designed and implemented. In this a theoretical study was done. A C program was made which gave the required
result for the graphical representation of the recorded radiation. Programmable Logic Controls (PLC) was used
instead of photo sensors, which are widely used for tracking the sun. The azimuthal angle of the sun from sunrise
to sunset times was calculated for each day of the year at 23.59 Lat & 72.38Longitude in the Northern hemisphere,
the location of the city Mehsana. According to this azimuth angle, the required analog signal was taken from the
PLC analog module and sent to the power window motor, which controlled the position of the panel to ensure that
the rays fall vertically on the panel. After the mechanical control of the system was started, the performance
measurements of the solar panel were carried out. The values obtained from the measurements were compared and
the necessary evaluations were conducted.
Average Channel Capacity of Amplify-and-forward MIMO/FSO Systems Over Atmosph...IJECEIAES
In amplify-and-forward (AF) relay channel, when the direct link between source and destination terminals is deeply faded, the signal from the source terminal to the destination terminal propagates through the relay terminals, each of which relays a signal received from the previous terminal to the next terminal in series. This paper, we theoretically analyze the performance of multiple-input multiple-output (MIMO) AF free-space optical (FSO) systems. The AF-MIMO/FSO average channel capacity (ACC), which is expressed in terms of average spectral efficiency (ASE) is derived taking into account the atmospheric turbulence effects on the MIMO/FSO channel. They are modeled by log-normal and the gamma-gamma distributions for the cases of weak-to-strong turbulence conditions. We extract closed form mathematical expression for the evaluation of the ACC and we quantitatively discuss the influence of turbulence strength, link distance, different number of relay stations and different MIMO configurations on it.
BER Performance of MU-MIMO System using Dirty Paper CodingIJEEE
In this paper Dirty Paper Coding for communication system is implemented. MIMO application that involves devices such as cell phones, pocket PCs require closely spaced antenna, which suffers from mutual coupling among antennas and high spatial correlation for signals. DPC is used for compensating the degradation due to correlation and mutual coupling.
In this paper, three beamforming design are considered for multi user MIMO system. First, transmit
beamformers are fixed and the receive (RX) beamformers are calculated. Transmit beamformer (TX-BF)is
projectedas a null space of appropriate channels. It reduces the interference for each user. Then the receiver
beamformer is determined which maximize the SNR. This beamforming design provides less computation time.
The second case is joint TX and RX beamformer for SNR maximization. In this transmitter and receiver
beamformer are calculated using extended alternating optimization (EAO) algorithm. The third one is joint
transmitter and receiver beamforming for SNR and SINR maximization using EAO algorithm. This algorithm
provides better error performance and sum rate performance. All the design cases are simulated by using
standard multipath channel model. Our simulation results illustrate that compared to the least square design and
zero forcing design, the joint TX and RX beamforming design using EAO algorithm provides faster
beamforming and improved error performance and sum rate.
Classical Discrete-Time Fourier TransformBased Channel Estimation for MIMO-OF...IJCSEA Journal
In this document, we look at various time domain channel estimation methods with this constraint of null carriers at spectrumborders.We showin detail howto gauge the importance of the “border effect” depending on the number of null carriers, which may vary from one system to another. Thereby we assess the limit of the technique discussed when the number of null carriers is large. Finally the DFT with the truncated singular value decomposition (SVD) technique is proposed to completely eliminate the impact of the null subcarriers whatever their number. A technique for the determination of the truncation threshold for any MIMO-OFDM system is also proposed.
The presentation is about Adaptive Beamforming for high data-rate applications. Analog beamforming, which is considered a cost effective solution for consumer devices are investigated. Two adaptive analog beamforming algorithms, i.e., a well-known perturbation-based and dmr-based which overcomes the drawbacks of perturbation-based algorithm are discussed in-detail and their performance comparisons are made with the help of computer simulations. Also variation of single-port structure is considered and it's benefits are exploited with the help of modified analog beamforming algorithms.
Performance Analysis of PAPR Reduction in MIMO-OFDMIJARBEST JOURNAL
Authors: Jayaraman.G1, VeeraKumar K2, Selvakani.S3
Abstract— In communication system, it is aimed to provide highest possible
transmission rate at the lowest possible power and with the least possible noise. MIMOOFDM
has been chosen for high data rate communications and widely deployed in many
wireless communication standards. The major drawback in OFDM signal transmission is
high PAPR. In previous, use clipping technique to tackle this problem. In this paper, use
EM-GAMP algorithm to reduce PAPR in considerable amount.
3D METALLIC PLATE LENS ANTENNA BASED BEAMSPACE CHANNEL ESTIMATION TECHNIQUE F...ijwmn
Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna
system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of
information from mobile devices. However, this estimation is required to ensure the perfect channel state
information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase
shifter (PS) components used in this estimation need high power to select the beam in the desired direction.
To overcome these limitations, in this work, we propose Regular Scanning Support Detection (RSSD)
based channel estimation mechanism. Moreover, we utilise a 3D lens antenna array having metallic plate
and a switch in our model which compensates the limitation of phase shifters. Simulation results show that
the proposed RSSD based channel estimation surpasses traditional technique and SD based channel
estimation even in lower SNR area which is highly desirable in the millimeter wave (mmWave) massive
MIMO systems.
Multi carrier equalization by restoration of redundanc y (merry) for adaptive...IJNSA Journal
This paper proposes a new blind adaptive channel shortening approach for multi-carrier systems. The
performance of the discrete Fourier transform-DMT (DFT-DMT) system is investigated with the proposed
DST-DMT system over the standard carrier serving area (CSA) loop1. Enhanced bit rates demonstrated
and less complexity also involved by the simulation of the DST-DMT system.
Orthogonal Frequency Division Multiplexing (OFDM) is deployed to overcome the interference. However,
OFDM has a relatively large OOB emissions. In spectrum sharing approaches such as dynamic spectrum
access networks, the OOB power levels of secondary transmissions should be kept below a certain level, in
order not to interfere with primary transmissions. . The difficulties such as sidelobes and PAPR caused by
OFDM is reduced by convex optimization and PTS technique respectively. In this technique each OFDM
subcarrier is multiplied with a real-valued weight that is determined in order not to interfere with adjacent
users. The problem with the SW technique is involving a very complex optimization. We propose a heuristic
approach called convex optimization. It can achieve considerable sidelobe suppression while requiring
significantly less computational resources than the optimal solution. Implementation results prove that it
can be introduced for real-time transmissions. Optimizing the subcarrier weights and SINR is complex, for
which we use the technique of convex optimization. For reducing the PAPR we use Partial Transmit
Sequence (PTS) technique.
Index terms : OFDM (Orthogonal Frequency Division Multiplexing), PAPR (Peak Average Power
Ratio), OOB (Out Of Band), IFFT (Inverse Fast Fourier Transform).
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.
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
A new look on CSI imperfection in downlink NOMA systemsjournalBEEI
Observing that cooperative scheme benefits to non-orthogonal multiple access (NOMA) systems, we focus on system performance analysis of downlink. However, spectrum efficiency is still high priority to be addressed in existing systems and hence this paper presents full-duplex enabling in NOMA systems. Other challenge needs be considered related to channel state information (CSI). In particular, we derive closedform expressions of outage probability for such NOMA systems under the presence of CSI imperfection. Furthermore, to fully exploit practical environment, we provide system model associated with Nakagami-m fading. The Monte-Carlo simulations are conducted to verify the exactness of considered systems.
Design and Fabrication of a Two Axis Parabolic Solar Dish CollectorIJERA Editor
The work consists of the design of the chain drive system and the fabrication of the two axis parabolic solar dish.
It is a model study of the two axis parabolic dish which worked by the automatic circuit that was developed. Ready
made parabolic solar dish is taken and fabricated. The circular iron ring provides the two axis motion of the dish.
A compound chain drive system was developed for the smooth movement of the dish. An electromechanical
system which tracks the sun on both axes and which is controlled via a programmable logic control (PLC) was
designed and implemented. In this a theoretical study was done. A C program was made which gave the required
result for the graphical representation of the recorded radiation. Programmable Logic Controls (PLC) was used
instead of photo sensors, which are widely used for tracking the sun. The azimuthal angle of the sun from sunrise
to sunset times was calculated for each day of the year at 23.59 Lat & 72.38Longitude in the Northern hemisphere,
the location of the city Mehsana. According to this azimuth angle, the required analog signal was taken from the
PLC analog module and sent to the power window motor, which controlled the position of the panel to ensure that
the rays fall vertically on the panel. After the mechanical control of the system was started, the performance
measurements of the solar panel were carried out. The values obtained from the measurements were compared and
the necessary evaluations were conducted.
Average Channel Capacity of Amplify-and-forward MIMO/FSO Systems Over Atmosph...IJECEIAES
In amplify-and-forward (AF) relay channel, when the direct link between source and destination terminals is deeply faded, the signal from the source terminal to the destination terminal propagates through the relay terminals, each of which relays a signal received from the previous terminal to the next terminal in series. This paper, we theoretically analyze the performance of multiple-input multiple-output (MIMO) AF free-space optical (FSO) systems. The AF-MIMO/FSO average channel capacity (ACC), which is expressed in terms of average spectral efficiency (ASE) is derived taking into account the atmospheric turbulence effects on the MIMO/FSO channel. They are modeled by log-normal and the gamma-gamma distributions for the cases of weak-to-strong turbulence conditions. We extract closed form mathematical expression for the evaluation of the ACC and we quantitatively discuss the influence of turbulence strength, link distance, different number of relay stations and different MIMO configurations on it.
BER Performance of MU-MIMO System using Dirty Paper CodingIJEEE
In this paper Dirty Paper Coding for communication system is implemented. MIMO application that involves devices such as cell phones, pocket PCs require closely spaced antenna, which suffers from mutual coupling among antennas and high spatial correlation for signals. DPC is used for compensating the degradation due to correlation and mutual coupling.
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.
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.
Performance analysis for power-splitting energy harvesting based two-way full...TELKOMNIKA JOURNAL
Energy harvesting relay network is considered as the promising solution for a wireless
communication network in our time. In this research, we present and demonstrate the system performance
of the energy harvesting based two-way full-duplex relaying network over Nakagami-m fading
environment. Firstly, we propose the analytical expressions of the achievable throughput and outage
probability of the proposed system. In the second step, the effect of various system parameters on
the system performance is presented and investigated. In the final step, the analytical results are also
demonstrated by Monte-Carlo simulation. The numerical results demonstrated and convinced
the analytical and the simulation results are agreed with each other.
BER Performance of Antenna Array-Based Receiver using Multi-user Detection in...ijwmn
Antenna promises to provide significant increases in system capacity and performance in
wireless systems. In this paper, a simplified, near-optimum array receiver is proposed,
which is based on the angular gain of the spatial filter. This detection is then analyzed by
calculating the exact error probability.The proposed model confirms the benefits of adaptive
antennas in reducing the overall interference level (intercell/intracell) and to find an
accurate approximation of the error probability. We extend the method that has been
proposed for propagation over Nakagami-m fading channels, the model shows good
agreements with simulation results.
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.
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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.
Using the Channel State Information (CSI) at the transmitter is fundamental for the precoder
design in Multi-user Multiple Input Single Output (MU-MISO-OFDM) systems. In Frequency
Division Duplex (FDD) systems, CSI can be just available at the transmitter through a limited
feedback channel [1], where we assume that each user quantizes its channel direction with a
finite number of quantization bits. In this paper, we consider a scalar quantization (SQ) scheme
of the Channel Direction Information (CDI). Although vector quantization (VQ) schemes [2],
[3] still outperform this scalar scheme in terms of quantization error and Sum rate, the former
scheme suffers from an exponential search complexity and high storage requirements at the
receiver for high number of feedback bits.
Performance of the MIMO-MC-CDMA System with MMSE EqualizationTamilarasan N
Multipath fading and spectral crowding are the
major challenges in dealing higher data rate in future
broadband wireless communication system. Multi-carrier
Modulation like Multicarrier code division multiple access
(MC-CDMA) can tackle the problem and provide higher data
rate for future wireless communication system. However,
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shifts which result in loss of the orthogonality among users
and generates Multiple access interference (MAI). To combat
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such as Maximum Ratio Combining (MRC), Equal Gain
Combining (EGC), Orthogonal Restoring Combining (ORC),
Threshold Orthogonal Restoring Combining or Minimum
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offers better performance since the MMSE criterion is applied
independently on each subcarrier. Further improvement in
performance is possible through space–time block coding,
which offers maximum diversity gain and multiplexing gain.
This paper combines MC-CDMA with MMSE equalization
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physical layer solution in combating delay spread and inter
symbol interference (ISI).
At this present scenario, the demand of the system capacity is very high in wireless network. MIMO
technology is used from the last decade to provide this requirement for wireless network antenna
technology. MIMO channels are mostly used for advanced antenna array technology. But it is most
important to control the error rate with enhanced system capacity in MIMO for present-day progressive
wireless communication. This paper explores the frame error rate with respect to different path gain of
MIMO channel. This work has been done in different fading scenario and produces a comparative analysis
of MIMO on the basis of those fading models in various conditions. Here, it is to be considered that
modulation technique as QPSK to observe these comparative evaluations for different Doppler frequencies.
From the comparative analysis, minimum amount of frame error rate is viewed for Rician distribution at
LOS path Doppler shift of 0 Hz. At last, this work is concluded with a comparative bit error rate study on
the basis of singular parameters at different SNR levels to produce the system performance for uncoded
QPSK modulation.
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Intersymbol interference caused by multipath in band limited frequency selective time dispersive channels distorts the transmitted signal, causing bit error at receiver. ISI is the major obstacle to high speed data transmission over wireless channels. Channel estimation is a technique used to combat the intersymbol interference. The objective of this paper is to improve channel estimation accuracy in MIMO-OFDM system by using modified variable step size leaky Least Mean Square (MVSSLLMS) algorithm proposed for MIMO OFDM System. So we are going to analyze Bit Error Rate for different signal to noise ratio, also compare the proposed scheme with standard LMS channel estimation method.
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1. Journal of Marine Science and Technology, Vol. 15, No. 4, pp. 287-294 (2007) 287
Paper Submitted 09/19/06, Accepted 12/14/06. Author for Correspondence:
Chi-Min Li. E-mail: cmli@mail.ntou.edu.tw
*Department of Communication and Guidance Engineering, National
Taiwan Ocean University, Keelung, Taiwan, R.O.C.
**Department of Environment and Energy, National University of Tainan,
Tainan, Taiwan, R.O.C.
Key words: W-CDMA, complex conjugate, direction-of-arrival.
ABSTRACT
Wideband Code Division Multiple Access (W-CDMA) adopts
the smart antenna techniques to increase the signal-to-interference-
noise ratio (SINR) and system capacity. In this paper, we statistically
derive analytic results to prove the SINR performance for the two
commonly used CC and DOA beamforming methods. Results show
the both methods will have the same mean SINR performance and CC
method will be more robust than the DOA method.
INTRODUCTION
As the rapid growth of utilization for modern
terrestrial radio system, more and more demands on
system capacity and throughput are required to satisfy
various kind of wireless applications [1, 5, 9]. Wideband
Code Division Multiple Access (W-CDMA), also known
as 3G system, adopts the smart antenna techniques to
increase the signal-to-interference-noise ratio (SINR)
and system capacity [2]. Based on the different adapta-
tion methods, smart antenna can be divided into two
categories, i.e., switched beam method and adaptive
array. A switched beam smart antenna uses a predeter-
mined high-gain beamwidth antenna for signal recep-
tion or transmission [7]. Intuitively, switched beam
array performs worse than the adaptive array, yet it has
the advantage that hardware implementation is more
easier compared with the adaptive array method. Adap-
tive antennas form the main beam to the desired user and
null the undesired interferences by an adjustable weight-
ing set. This weightings set can be obtained via some
criteria such as MMSE, LMS, RLS..etc [3]. Among
these methods, Complex Conjugate (CC) and Direc-
tion-of-Arrival (DOA) methods are two widely used
methods due to its simplicity and fast weightings calcu-
lation capability [4].
Recently, some performance results for the CC
and DOA beamforming methods were reported. Li and
Liu [6] stated that the CC and DOA have almost the
same SINR performance in the uplink channel based
only on computer simulations. And the CC method will
have 1dB SINR degradation worse than the DOA method
if the weightings estimated in the uplink are applied to
the downlink channel. In this paper, we have estab-
lished analytic SINR evaluation equations for the CC
and DOA methods in a W-CDMA smart antenna.
Besides, performance and robustness analyses of the
two methods under different channel scenarios are given
for further verifications. Two different channel sce-
narios are considered, one is in perfect channel estima-
tion condition and the other is estimated with errors.
According to the 3GPP specifications [8], channel at-
tenuation and time-of-arrival (TOA) can be estimated
by the Match Filter (MF) and known pilot symbols in the
dedicated physical control channel (DPCCH) of the
WCDMA system in the uplink transmission. With these
parameters, performance analysis of different beam-
forming techniques can be evaluated.
The paper is organized as follow: Section II gives
a brief review of the CC and DOA methods and derives
analytic SINR results for both methods. The derivatives
consider fading channel with Additive-White-Gaussian-
Noise (AWGN) and Multiple Access Interference (MAI).
In Section III, simulation results on the derived results
will be given to verify their performances. We consider
both the Line-of-Sight (LOS) and Non-LOS (NLOS)
wireless channel in the simulation. Finally, some con-
clusions are given in Section IV for this paper.
SYSTEM DESCRIPTIONS
In a W-CDMA system, a M-elements antenna ar-
ray with P-fingers Rake Receiver that receives the 0th
user’s signal can be illustrated as
where wp,m,k is the attenuation compensation
AN ANALYTIC ANALYSIS OF W-CDMA SMART
ANTENNAS BEAMFORMING USING COMPLEX
CONJUGATE AND DOA METHODS
Chi-Min Li*, Jia-Chyi Wu*, and I-Tseng Tang**
2. Journal of Marine Science and Technology, Vol. 15, No. 4 (2007)288
weighting at time τp,m,k. τp,m,k is the time-of-arrival
(TOA) of the pth multipath at the mth receiving antenna
for the kth user. In general, SINR of the received signal
can be increased by the properly chosen weightings
wp,m,k of each antenna. Two simple and efficient weight-
ing adjust methods, the CC and DOA are briefly re-
viewed as follow.
1. CC (complex conjugate) beamforming
The CC method uses the estimated TOA τj of the
desired signal to predict the delay profile attenuation h
^
of each antenna element. Once h^
be estimated, we can
use Eq.(1) to determine the weightings of each antenna.
wij = h i
*
(τj) (1)
where i = 1 ~ M, j = 1 ~ P. the weightings
Intuitively, the CC method multiplies the complex
conjugate of the DPCCH estimation to compensate the
channel attenuation and maximizes the SINR. Therefore,
receiver sums up the compensated signals of each ele-
ment to detect the transmitted symbol. It has the advan-
tage of simple computation and operates like the Maxi-
mum Ratio Combining (MRC) method which is the
optimal diversity combining technique.
2. DOA (direction-of-arrival) beamforming
Compared with the CC method, DOA method uses
another estimated signal parameter: DOA, to decide the
weightings wij. Due to the phase relation of the received
signal and the geometry of antenna array (a linear equal
space antenna array with half-wavelength separation is
considered in this paper), wij can be determined by
Eq.(2)
wij = w1j
*
e– j 2π (i – 1) (d / λ) cos θj (2)
where i = 1 ~ M, j = 1 ~ P. w1j = h
^
1(τj)*
, λ is the wave-
length, d is the antenna separation.
In the DOA method, channel compensation can be
achieved by the phase relation of the incident signals.
Once the attenuated signals are compensated, signals of
different antennas are summed up to decide the trans-
mitted symbol.
Besides, a P-paths time-invariant channel for the
kth user at the mth receiving antenna can be modeled as
hm,k(t) = hp,m,kδ (t – τp,m,k)Σp= 0
P–1
(3)
Let the DPCCH and dedicated physical data chan-
nel (DPDCH) of the desired user have the spreading
factor Fc and Fd respectively. Assume the 0th
user is the
desired signal for processing, the pth finger output
voltages yc,p,m, yd,p,m of the matched filter (MF) for the
DPCCH and DPDCH can be expressed separately as
yc,p,m = Fchp,m,0 + ic,p,m + nc,p,m
= Fchp,m,0 + ηc,p,m (4)
yd,p,m = bFdhp,m,0 + id,p,m + nd,p,m
= bFdhp,m,0 + ηd,p,m (5)
where hp,m,0 is the pth multipath attenuation for the
desired user, ic,p,m, id,p,m and nc,p,m, nd,p,m are the pth
multiple access interference (MAI) and AWGN thermal
noise at the DPCCH and DPDCH channel at the m-th
receiving antenna. The statistical properties of these
random variables are
E ic,p,m
2
= Fc(K – 1)
E nc,p,m
2
= Fcσn
2
E ηc,p,m
2
= E ic,p,m
2
+ E nc,p,m
2
= Fc[(K – 1) + σn
2] (6)Fig. 1. A -elements antenna array with-fingers rake receiver.
P,1,0
w
w
y (t)
1,1,0 1,1,0τ
τ
τ
τ
τ
2,1,0 2,1,0
w
w
w
w
P,1,0
1,M,0 1,M,0
2,M,0 2,M,0
τP,M,0 P,M,0
3. C.M. Li et al.: An Analytic Analysis of W-CDMA Smart Antennas Beamforming Using Complex Conjugate and DOA Methods 289
E id,p,m
2
= Fd(K – 1)
E nd,p,m
2
= Fdσn
2
E ηd,p,m
2
= E id,p,m
2
+ E nd,p,m
2
= Fd[(K – 1) + σn
2] (7)
where K is the total number of users.
Assume that the DPCCH and DPDCH have the
same channel characteristics during transmission, by
using the CC method to combine the RAKE finger
outputs, the output voltage of the DPDCH smart an-
tenna receiver Vout is given by
Vout = yd,p,m yc,p,m
*
Σp=1
P
Σm=1
M
(8)
Suppose that the DPCCH can estimate the channel
perfectly, i.e., ηc,p,m = ic,p,m + nc,p,m = 0, we have
Vout = (bFd hp,m,0 + ηd,p,m)Fc hp,m,0
*
Σp=1
P
Σm=1
M
= bFdFc hp,m,0
2
Σp=1
P
+ ηd,p,m Fc hp,m,0
*
Σp=1
P
Σm=1
M
Σm=1
M
(9)
The SINR for the P-fingers CC RAKE receiver at the
DPDCH is
SINRPerfect
P
=
Fd
2
Fc
2
( hp,m,0
2
Σp=1
P
Σm=1
M
)
2
E ηd,p,m Fc hp,m,0
*
Σp=1
P
Σm=1
M
2
=
Fd ( hp,m,0
2
Σp=1
P
Σm=1
M
)
(K – 1) + σn
2
(10)
where we have assumed that E{ηd,p,mη*
c,p,m} = 0 and
E{ηd,p,mη*
c,p',m} = 0 for p ≠ p'. Note that if we assume
that hp,m,0 is a complex Gaussian random variable with
zero mean and variance 2σ2
, then, |hp,m,0|2
will be a Chi-
square distributed random variable and hp,m,0
2
Σp=1
P
Σm=1
M
will also be a Chi-square distributed random variable
with mean 2MPσ2
and variance 4MPσ4
. That is, the
received SINR of the CC method can be modeled as a
Chi-square distributed random variable with mean
2AMPσ2
, variance 4A2
MPσ4
according to Eq.(10), where
A = Fd/(K – 1) + σn
2
.
If the DPCCH is unable to estimate the channel
perfectly, i.e., ηc,p,m = ic,p,m + nc,p,m ≠ 0, we find that the
output voltage of the DPDCH RAKE receive Vout is
Vout = bFd hp,m,0 + ηd,p,m Fc hp,m,0
*
+ ηc,p,m
*
Σp=1
P
Σm=1
M
= bFdFc hp,m,0
2
+ bFd hp,m,0ηc,p,m
*
Σp=1
P
Σm=1
M
Σp=1
P
Σm=1
M
+ ηd,p,m Fc hp,m,0
*
Σp=1
P
Σm=1
M
+ ηd,p,m ηc,p,m
*
Σp=1
P
Σm=1
M
(11)
The SINR for the P-fingers CC RAKE receiver at the
DPDCH is given by
SINRP
Interference
=
Fd
2
Fc
2
( hp,m,0
2
Σp=1
P
Σm=1
M
)
2
E bFd hp,m, 0 ηc,p,m
*
Σp=1
P
Σm=1
M
+ ηd,p,m Fc hp,m,0
*
Σp=1
P
Σm=1
M
+ ηd,p,m ηc,p,m
*
Σp=1
P
Σm=1
M
2
=
Fd Fc ( hp,m,0
2
Σp=1
P
Σm=1
M
)
2
(K – 1) + σn
2 (Fd + Fc ) hp,m,0
2
+ PM (K – 1) + σn
2
Σp=1
P
Σm=1
M
(12)
where we have assumed that E{ηd,pη*
d,p'} = 0 for p ≠ p',
E{ηc,pη*
c,p'} = 0 for p ≠ p' and E{ηc,pη*
d,p'} = 0 for all
p, p'. The performance degradation due to the channel
estimation error by using the CC method can therefore
be expressed as
Degradation=
SINRInterference
P
SINRPerfect
P
=
Fc ( hp,m,0
2
Σp=1
P
Σm=1
M
)
(Fd + Fc ) hp,m,0
2
+ PM (K – 1) + σn
2
Σp=1
P
Σm=1
M (13)
4. Journal of Marine Science and Technology, Vol. 15, No. 4 (2007)290
Considering another case, if we use the DOA
method to determine the weightings, the output voltage
of the DPDCH smart antenna receiver Vout is given by
Vout = yd,p,m yc,p,1
*
e– j (m – 1) π cos θpΣp=1
P
Σm=1
M
(14)
where θp is the AOA of the p-th multipath of the desired
user. Suppose that the DPCCH can estimate the channel
perfectly, i.e., ηc,p,m = ic,p,m + nc,p,m = 0, we have
Vout = bFd hp,m,0 + ηd,p,m (Fc hp,1,0
*
e– j (m – 1) π cos θp)Σp=1
P
Σm=1
M
= bFdFc hp,m,0 hp,1,0
*
e– j (m – 1) π cos θpΣp=1
P
Σm=1
M
+ ηd,p,m, Fc hp,1,0
*
e– j (m – 1) π cos θpΣp=1
P
Σm=1
M
(15)
The SINR for the P-fingers DOA smart antenna receiver
at the DPDCH is
SINRPerfect
P
=
Fd
2
Fc
2
(M hp,1,0
2
)Σp=1
P
2
E ηd,p,mΣp=1
P
Σm=1
M
Fc hp,1,0
*
e– j (m – 1) π cos θp
2
=
Fd
2
Fc
2
(M hp,1,0
2
)Σp=1
P
2
Fd Fc
2
{(K –1) + σn
2
}(M hp,1,0
2
)Σp=1
P
=
Fd (M hp,1,0
2
)Σp=1
P
{(K – 1) + σn
2
}
(16)
where we have assumed that E{ηd,p,mη*
c,p,m} = 0 and
E{ηd,p,mη*
d,p',m} = 0 for p ≠ p'. Note that if we assume
that hp,1,0 is a complex Gaussian random variable with
zero mean and variance 2σ2
, then, the received SINR of
the DOA method can be described as a Chi-square
distributed random variable with mean 2AMPσ2
and
variance 4A2
M2
Pσ4
.
If the DPCCH in unable to estimate the channel
perfectly, i.e., ηc,p,m = ic,p,m + nc,p,m ≠ 0, the output
voltage of the DPDCH smart antenna receiver Vout is
given by
Vout
= bFd hp,m,0 + ηd,p,m Fchp,1,0
*
e– j (m – 1) π cos θp + ηc,p,m
*
Σp=1
P
Σm=1
M
= bFdFcM hp,1,0
2
+ bFd hp,m,0ηc,p,m
*
Σp=1
P
Σm=1
M
Σp=1
P
+ ηd,p,m Fc hp,1,0
*
e– j (m – 1) π cos θp +Σp=1
P
ηd,p,mηc,p,m
*
Σp=1
P
Σm=1
M
Σm=1
M
(17)
The SINR for the P-fingers DOA RAKE receiver at the
DPDCH is given by
SINRP
Interference
=
Fd
2
Fc
2
(M hp,1,0
2
)Σp=1
P
2
E bFd hp,m,0 ηc,p,m
*
Σp=1
P
Σm=1
M
+ ηd,p,m, Fchp,1,0
*
e– j (m – 1) π cos θpΣp=1
P
Σm=1
M
+ ηd,p,m ηc,p,m
*
Σp=1
P
Σm=1
M
2
=
Fd
2
Fc
2
(M hp,1,0
2
)Σp=1
P
2
Fd
2
Fc[(K – 1) + σn
2 ]{ hp,m,0
2
}Σp=1
P
Σm=1
M
+ Fc
2
Fd[(K – 1) + σn
2 ]{M hp,1,0
2
} + Fc FdPM[(K – 1) + σn
2]2
Σp=1
P
=
FdFc (M hp,1,0
2
)Σp=1
P
2
[(K – 1) + σn
2] Fd hp,m,0
2
+ Fc M hp,1,0
2
+ PM[(K – 1) + σn
2]Σp=1
P
Σp=1
P
Σm=1
M
(18)
where we have assumed that E{ηd,p,mη*
c,p',m} = 0 for
p ≠ p', E{ηc,p,mη*
c,p',m} = 0 for p ≠ p' and E{ηc,p,mη*
d,p',m}
= 0 for all p ≠ p'. The performance degradation due to
the channel estimation error by using the DOA method
can therefore be expressed as
Degradation=
SINRInterference
P
SINRPerfect
P
5. C.M. Li et al.: An Analytic Analysis of W-CDMA Smart Antennas Beamforming Using Complex Conjugate and DOA Methods 291
=
Fd Fc (M hp,1,0
2
)Σp=1
P
2
(K – 1) + σn
2 Fd hp,m,0
2
+ Fc M hp,1,0
2
+ PM (K – 1) + σn
2
Σp=1
P
Σp=1
P
Σm=1
M
Fd(M hp,1,0
2
)Σp=1
P
[(K –1) + σn
2 ]
=
Fc(M hp,1,0
2
)Σp=1
P
Fd hp,m,0
2
+ Fc M hp,1,0
2
+ PM (K – 1) + σn
2
Σp=1
P
Σp=1
P
Σm=1
M
(19)
An interesting result can be observed if we look
into Eq.(10) and Eq.(16) which are the SINR perfor-
mance of the CC and DOA methods respectively under
the perfect channel estimation scenario. Table 1 lists
the summary of the derived results.
Table 1 reveals that both the CC and DOA methods
will have the same mean SINR performance statistically.
And the SINR will be increase if we increase either M
(antenna number) or P (RAKE finger number) at the
receiver. However, the CC method has less SINR
variation (4AMPσ4
in the CC case versus 4AM2
Pσ4
in
the DOA case) compared with the DOA method. It
implies that the output SINR of the CC method will be
more stable than the DOA method. This result comes
from the assumption of the DOA method that the inci-
dent signals received by the array differ only in phase.
And the phase difference is linear proportional to the
antenna spacing. Same phenomenon occurs in Eq.(12)
and Eq.(18) for the CC and DOA method when the
channel estimation contains errors from the MAI and
AWGN.
SIMULATIONS
In this section, we simulate the derived results to
analyze the performance of the CC and DOA techniques.
We assume that perfect power control of the system can
be achieved and all multipaths attenuations are indepen-
dent and identically distributed. Assuming there are 20
active users in the coverage of a base station, the serving
base station adopts smart antennas with M receiving
elements for receiving. Each receiving antenna consists
of a P-fingers RAKE receiver to form the coherent
output for detection. The spreading factors (SF) set to
64 in the DPDCH channel and 256 in the DPCCH
channel for all active users. Besides, σ2
n = σ = 1 and
|hp, m, k| are either Rayleigh or Ricean fading depends on
the channel environment. Both the line-of-sight (LOS)
and the non-line-of-sight (NLOS) cases are considered
in this simulation.
Figure 2 and Figure 3 are the estimated cumulative
Fig. 2. CDF of the SINR using CC method under perfect channel
estimation.
Table 1. Summary of the CC and DOA Performance
CC DOA
Distribution of Chi-Square Chi-Square
SINR distributed distributed
Expectation 2AMPσ2
2AMPσ2
Variance 4A2
MPσ4
4A2
M2
Pσ4 Fig. 3 CDF of the SINR using DOA method under perfect channel
estimation.
10 12 14 16 18 20 22 24 26 28 30
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
SINR distribution for the CC method
SINR (dB)
M = 3, P = 1
M = 3, P = 3
M = 3, P = 5
M = 3, P = 7
M = 2, P = 1
M = 2, P = 3
M = 2, P = 5
M = 2, P = 7
CDFoftheSINR
10 12 14 16 18 20 22 24 26 28 30
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
SINR (dB)
SINR distribution for DOA method
CDFoftheSINR
M = 3, P = 1
M = 3, P = 3
M = 3, P = 5
M = 3, P = 7
M = 2, P = 1
M = 2, P = 3
M = 2, P = 5
M = 2, P = 7
6. Journal of Marine Science and Technology, Vol. 15, No. 4 (2007)292
distribution function (CDF) results of the SINR if the
channels are randomly generated 1000 times under the
perfect channel estimation case. The number of receiv-
ing antennas M could be either 2 or 8 while the finger
number P could be 1, 3, 5, 7. In LOS case, Ricean factor
of the channel is set to 3.52 dB. Comparing Figure 2
with Figure 3, we notice that both the CC and DOA
methods have approximately the same mean SINR
performance. For example, for M = 8, P = 1 in Figure 2,
SINR of the CC has approximately 21 dB and ranges
from 19 dB to 25 dB, while for M = 8, P = 1 in Figure 3,
SINR of the DOA has approximately the same 21 dB,
yet, its SINR ranges from 10 dB to 28 dB. That is, the
CC method is more robust because its output SINR has
less variation. This result confirms our pervious predic-
tion for the two methods.
Figure 4 and Figure 5 are the estimated CDF
results of the SINR if the channels are not perfect
channel estimated. We can note that same mean SINR
performance for both the CC and DOA methods and the
CC method is more robust than the DOA method even in
the imperfect channel estimation case.
Similar simulation results for the NLOS case are
illustrated from Figure 6 to Figure 9. Except for the
Ricean factor (-∞ dB for NLOS), all parameters are the
same as in the LOS case. Table 2 lists the detail
Fig. 4. CDF of the SINR using CC method under imperfect channel
estimation.
Fig. 5. CDF of the SINR using DOA method under imperfect channel
estimation.
SINR distribution for the CC method
10 12 14 16 18 20 22 24 26 28 30
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
SINR (dB)
CDFoftheSINR
M = 3, P = 1
M = 3, P = 3
M = 3, P = 5
M = 3, P = 7
M = 2, P = 1
M = 2, P = 3
M = 2, P = 5
M = 2, P = 7
Fig. 6. CDF of the SINR using CC method under perfect channel
estimation in NLOS Case.
10 12 14 16 18 20 22 24 26 28 30
SINR (dB)
SINR distribution for DOA method
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
CDFoftheSINR
M = 3, P = 1
M = 3, P = 3
M = 3, P = 5
M = 3, P = 7
M = 2, P = 1
M = 2, P = 3
M = 2, P = 5
M = 2, P = 7
Fig. 7. CDF of the SINR using DOA method under perfect channel
estimation in NLOS case.
0 5 10 15 20 25 30
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
SINR (dB)
SINR distribution for the CC method
CDFoftheSINR M = 3, P = 1
M = 3, P = 3
M = 3, P = 5
M = 3, P = 7
M = 2, P = 1
M = 2, P = 3
M = 2, P = 5
M = 2, P = 7
0 5 10 15 20 25 30
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
SINR (dB)
CDFoftheSINR
SINR distribution for DOA method
M = 3, P = 1
M = 3, P = 3
M = 3, P = 5
M = 3, P = 7
M = 2, P = 1
M = 2, P = 3
M = 2, P = 5
M = 2, P = 7
7. C.M. Li et al.: An Analytic Analysis of W-CDMA Smart Antennas Beamforming Using Complex Conjugate and DOA Methods 293
numerical expectations and distributions for the CC and
DOA SINR performance in Figure 6 and Figure 7.
Figure 10 describes the relations of the calculated
standard deviation versus M and P under the LOS
channel. Results show that the SINR of the CC method
has less variation than the DOA method for the same M
and P. Besides, SINR variation increases linear propor-
tional to M in the CC method and approximately M2
in
the DOA method.
CONCLUSIONS
In this paper, we established analytic SINR evalu-
ation equations of the CC and DOA methods in a W-
CDMA smart antenna. Performance and robustness
analyses of the two methods under perfect and imper-
fect channel estimation scenarios are also derived. Re-
sults show that both methods have the same mean SINR
performance where the CC method presents more robust
than the DOA method under all simulated scenarios.
ACKNOWLEDGMENTS
This research work was supported by the National
Science Council of the Republic of China under the
Grant number NSC 95-2221-E-019-018.
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