2012 Conference Record of the Forty Sixth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), 2012
ABSTRACT We consider distributed total transmit power minimization in single-sink data gathering ... more ABSTRACT We consider distributed total transmit power minimization in single-sink data gathering wireless sensor network via joint optimization of routing and resource allocation with given source rates. There exists numerous decentralized cross-layer optimization algorithms derived via dual decomposition over the physical and network layer. We propose a consensus based distributed optimization algorithm which applies alternating direction method of multipliers to efficiently solve the problem with low message passing. Numerical examples illustrate how significantly faster the proposed algorithm converges as compared to the state of the art method based on dual decomposition.
2013 IEEE Global Conference on Signal and Information Processing, 2013
ABSTRACT We consider the sum power minimization problem with user specific rate constraint in the... more ABSTRACT We consider the sum power minimization problem with user specific rate constraint in the context of uplink LTE-A type system with carrier aggregation (CA), more precisely, inter-band CA. The increased bandwidth in LTE-A system allows orthogonal allocation of subcarriers among users. If time sharing or non-linear receivers are assumed, the problem becomes convex and can be optimally solved by standard solvers. We adopt a Lagrangian dual decomposition method in the conventional single band LTE type system to solve the subcarrier allocation problem. We further propose a subcarrier allocation and power control algorithm for the wideband CA. Because of the non-convex nature of the orthogonal subcarrier allocation, the optimal solution is not guaranteed. However, it is shown in the simulation results, that when there are sufficient available bandwidth, the performance gap between the optimal solution is small. The simulation results show with the proposed fast algorithms, the CA performs better than the conventional single band system. The gains become larger as the frequency selectivity increases.
2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, 2006
This paper presents a subspace-based algorithm for the simultaneous estimation of angle of arriva... more This paper presents a subspace-based algorithm for the simultaneous estimation of angle of arrivals (AOAs) and angle of departures (AODs) from an estimated spatial signature at the receive antenna array. The algorithm exploits a 2-D unitary ESPRIT-like technique to separate and estimate the phase shifts due to the AOAs and AODs with automatic pairing of the two parameter sets. The Cramer-Rao lower bound (CRLB) on the AOAs and AODs estimates is provided. The performance of the algorithm is illustrated based on the computer simulation. It shows that the proposed algorithm is an efficient estimator which is able to achieve the CRLB
Ninth IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (Cat. No.98TH8361), 1998
Abstract| In this paper, the performance of some code acquisition schemes are studied in the down... more Abstract| In this paper, the performance of some code acquisition schemes are studied in the downlink of DS-CDMA systems. The conventional matched lter, the minimum variance method, the MUSIC algorithms and the eigenvector method based delay acquisition schemes are studied in a frequency-selective fading channel. The three last algorithms are based on di erent estimation schemes for the inverse of the sample-covariance matrix. Based on the results, the minimum variance based method can be used to improve the acquisition performance in comparison to the conventional non-coherent matched lter method. The MUSIC algorithm becomes useless in highly loaded systems. The best performance, however, was obtained by using a longer despreading interval in the conventional delay estimator. Unfortunately, it would require either unmodulated pilot channel or a control channel with lower data rate, which may not be available in all applications.
IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference, 2008
Opportunistic user allocation and multiple antenna transmission provide significant performance e... more Opportunistic user allocation and multiple antenna transmission provide significant performance enhancement in future wireless communication systems. In this paper, theoretical outage capacity analysis of user allocation in downlink orthogonal frequency division multiple access (OFDMA) with multiple antenna transmission and limited feedback is presented. Several multiple antenna transmission schemes are considered in OFDMA system, where resources are allocated according to the resource-wise signal-to-noise ratio (SNR) quantization. Performance results show that the resource-wise one bit feedback from few uncorrelated resources provides significant allocation gain. Numerical results based on the analysis are compared to those obtained by computer simulations to validate the correctness of the proposed analysis.
The signal and threshold quantization effects on the performance of the total-power radiometer de... more The signal and threshold quantization effects on the performance of the total-power radiometer detector are studied. The goal is to define the sufficient number of quantization bits to maintain acceptable performance when the noise level estimate is assumed to be perfect. In addition, we study the effects of the dynamic range related to noise level. The simulations illustrate that the selection of the dynamic range affects the performance enormously. The noise should not be allowed to be saturated. If the dynamic range is set correctly, 4 bits is a sufficient number for signal quantization.
ABSTRACT This letter introduces diagnostic impulse-detection methods in general, and, based on th... more ABSTRACT This letter introduces diagnostic impulse-detection methods in general, and, based on those, presents three iterative impulse detectors for communication receivers with an antenna array. These detectors are implemented either in a backward or forward search mode. The forward methods are shown to perform better. They can detect all the impulses, even though 90% of all the samples are corrupted.
This paper proposes practical coordinated linear transmit-receive processing schemes for the upli... more This paper proposes practical coordinated linear transmit-receive processing schemes for the uplink (UL) of multiuser multipleinput multiple-output (MIMO) systems in the time division duplex (TDD) mode. The base station (BS) computes the transmission parameters in a centralized manner and employs downlink (DL) pilot signals to convey the information of the beam selection and beamformers to be used by the terminals. When coexisting with the DL transmit-receive zero forcing, the precoded DL demodulation pilots can be reused for UL beam allocation so that no additional pilot overhead is required. Furthermore, the locally available channel state information (CSI) of the effective MIMO channel is sufficient for the terminals to perform transmit power and rate allocation independently. In order to reduce the UL pilot overhead as well, we propose reusing the precoded UL demodulation pilots in turn for partial CSI sounding. The achievable sum rate of the system is evaluated in time-varying fading channels and with channel estimation. According to the results, the proposed UL transmission strategy provides increased rates compared to single-user MIMO transmission combined with user selection as well as to UL antenna selection transmission, without being sensitive to CSI uncertainty.
It is foreseen that a single (wideband) air interface mode is not sufficient for achieving the hi... more It is foreseen that a single (wideband) air interface mode is not sufficient for achieving the high spectral efficiency targets set for next generation wireless system. A dual-bandwidth approach is adapted to simultaneously provide wide coverage and high capacity in a large range of different operating envi-ronments. In this paper, hybrid diversity-multiplexing scheme, where Space-time Turbo Coded Modulation (STTuCM) and layered space-time architectures are combined, is used as the air interface for the wide area communication to provide high spectral efficiency and robustness against spatial fading corre-lation. A system level performance study with different radio resource allocation functionalities applied to the proposed low bandwidth STTuCM orthogonal frequency division multiplexing air interface concept is conducted. The simulation results from the developed system level simulator indicate that the dynamic channel allocation (DCA) results in far better performance than the ran...
The least squares (LS) channel estimation algorithm for a multiple-input multiple-output (MIMO) s... more The least squares (LS) channel estimation algorithm for a multiple-input multiple-output (MIMO) system with orthog-onal frequency division multiplexing (OFDM) is considered in this paper. Two architectures for the algorithm are pre-sented and the architectures are implemented using fixed point arithmetic. The minimum word lengths for the imple-mentations are determined through computer simulations for 2 × 2 and 4 × 4 MIMO systems with quadrature phase-shift keying (QPSK) modulation. Field-programmable gate array (FPGA) synthesis simulation is done for the architec-tures using the obtained word lengths which provides com-plexity and latency results. The algorithm implementations are shown to consume reasonably small amount of hardware resources.
VTC '98. 48th IEEE Vehicular Technology Conference. Pathway to Global Wireless Revolution (Cat. No.98CH36151), 1998
The performance of the multi-code (MC) access system with one processing gain and the multiple pr... more The performance of the multi-code (MC) access system with one processing gain and the multiple processing gain (MPG) access for asynchronous multirate code-division multiple-access (CDMA) systems are considered. The bit error rates (BER) of the decorrelating, parallel interference canceler (PIC) and groupwise serial interference canceler (GSIC) with either the PIC or decorrelator within the group are compared. The results show
VTC '98. 48th IEEE Vehicular Technology Conference. Pathway to Global Wireless Revolution (Cat. No.98CH36151), 1998
The decorrelating multiuser detector for asynchronous multirate multiuser code-division multiple-... more The decorrelating multiuser detector for asynchronous multirate multiuser code-division multiple-access (CDMA) systems is analyzed. A multirate CDMA system model able to fit several system concepts in the same framework is presented. The performance of the multi-code (MC) system with one processing gain and a multiple processing gain (MPG) system is compared. Lower bounds for the expected value of the asymptotic multiuser efficiency of a synchronous multirate CDMA system with three effective users are derived for a system with one and two processing gains. The numerical results show that the performance of the decorrelating detector for MC and MPG systems do not differ significantly
Proceedings of 6th International Symposium on Personal, Indoor and Mobile Radio Communications, 1995
For synchronous CDMA systems the decorrelating multiuser detector is the inverse of the correlati... more For synchronous CDMA systems the decorrelating multiuser detector is the inverse of the correlation matrix of the signature waveforms. The noise-whitening multiuser detector is the inverse of the Cholesky factor of the correlation matrix. If the number of users or the signature signals changes, the detectors must be recomputed. The paper introduces order-recursive algorithms for detector update. The algorithms compute
The inclusion of groupwise interference cancellation techniques into WCDMA uplink receivers is st... more The inclusion of groupwise interference cancellation techniques into WCDMA uplink receivers is studied in this paper. Emerging third generation WCDMA signal structures for multirate transmission are utilized along with necessary uplink techniques, namely antenna diversity reception, transmitter power control and signal-to-interference ratio (SIR) estimation. A groupwise serial interference cancellation (GSIC) technique suitable for WCDMA systems using long spreading sequences is
11th IEEE International Symposium on Personal Indoor and Mobile Radio Communications. PIMRC 2000. Proceedings (Cat. No.00TH8525), 2000
... PIC Receiver Kimmo Kansanen Jianke Fan Markku Juntti Matti Latva-aho University of Oulu, Cent... more ... PIC Receiver Kimmo Kansanen Jianke Fan Markku Juntti Matti Latva-aho University of Oulu, Centre for Wireless Communications PO Box 4500, FIN-90014 University of Oulu, Finland tel. f358 8 553 2833, fax. f358 8 553 2845 { kimmo . kansanen, fan. jianke,markku. junt ti,mat t i ...
2004 IEEE 15th International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE Cat. No.04TH8754), 2004
We evaluate the performance of single- and multi-antenna multi-carrier code division multiple acc... more We evaluate the performance of single- and multi-antenna multi-carrier code division multiple access (MC-CDMA) downlink (base station to mobile terminal) systems in multi-cell environments. We first propose a minimum mean square error (MMSE) filter for a single input single output (SISO) MC-CDMA downlink system. Then, we apply it to a SIMO (single input multiple output) system with a conventional turbo
The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2002
A design method for recursive space-time trellis codes and parallel concatenated space-time turbo... more A design method for recursive space-time trellis codes and parallel concatenated space-time turbo coded modulation was recently proposed as a new framework for building optimized, low-complexity, large equivalent constraint-length space-time trellis codes. In this paper the distance spectrum interpretation of the space-time turbo coded modulation is introduced to evaluate the union bound on the frame error rate over fast fading channels. The distance spectrum gives a good insight on the importance of multiplicities in the space-time coding design. Derived bounds are in some cases very tight and provide a designer with the practical tool for further optimization of the constituent space-time trellis codes within the space-time turbo coded modulation framework. Some interesting examples of the convergence of the sub-optimal iterative decoding were also presented.
We propose a new bandwidth and power efficient signaling scheme for achieving high data rates ove... more We propose a new bandwidth and power efficient signaling scheme for achieving high data rates over wideband radio channels exploiting bandwidth efficient OFDM modulation, multiple transmit and receive antennas and large frequency selectivity offered in typical low mobility indoor environments. Due to its maximum achievable transmit diversity gain and large coding gain, space-frequency turbo coded modulation strongly outperforms other space-frequency coding schemes recently proposed in literature. We also propose a simple way of combining space-frequency coding with OFDM delay diversity as a cost-effective method for further bandwidth efficiency increase by exploiting more than two antennas at the transmitter.
2012 Conference Record of the Forty Sixth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), 2012
ABSTRACT We consider distributed total transmit power minimization in single-sink data gathering ... more ABSTRACT We consider distributed total transmit power minimization in single-sink data gathering wireless sensor network via joint optimization of routing and resource allocation with given source rates. There exists numerous decentralized cross-layer optimization algorithms derived via dual decomposition over the physical and network layer. We propose a consensus based distributed optimization algorithm which applies alternating direction method of multipliers to efficiently solve the problem with low message passing. Numerical examples illustrate how significantly faster the proposed algorithm converges as compared to the state of the art method based on dual decomposition.
2013 IEEE Global Conference on Signal and Information Processing, 2013
ABSTRACT We consider the sum power minimization problem with user specific rate constraint in the... more ABSTRACT We consider the sum power minimization problem with user specific rate constraint in the context of uplink LTE-A type system with carrier aggregation (CA), more precisely, inter-band CA. The increased bandwidth in LTE-A system allows orthogonal allocation of subcarriers among users. If time sharing or non-linear receivers are assumed, the problem becomes convex and can be optimally solved by standard solvers. We adopt a Lagrangian dual decomposition method in the conventional single band LTE type system to solve the subcarrier allocation problem. We further propose a subcarrier allocation and power control algorithm for the wideband CA. Because of the non-convex nature of the orthogonal subcarrier allocation, the optimal solution is not guaranteed. However, it is shown in the simulation results, that when there are sufficient available bandwidth, the performance gap between the optimal solution is small. The simulation results show with the proposed fast algorithms, the CA performs better than the conventional single band system. The gains become larger as the frequency selectivity increases.
2006 IEEE 17th International Symposium on Personal, Indoor and Mobile Radio Communications, 2006
This paper presents a subspace-based algorithm for the simultaneous estimation of angle of arriva... more This paper presents a subspace-based algorithm for the simultaneous estimation of angle of arrivals (AOAs) and angle of departures (AODs) from an estimated spatial signature at the receive antenna array. The algorithm exploits a 2-D unitary ESPRIT-like technique to separate and estimate the phase shifts due to the AOAs and AODs with automatic pairing of the two parameter sets. The Cramer-Rao lower bound (CRLB) on the AOAs and AODs estimates is provided. The performance of the algorithm is illustrated based on the computer simulation. It shows that the proposed algorithm is an efficient estimator which is able to achieve the CRLB
Ninth IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (Cat. No.98TH8361), 1998
Abstract| In this paper, the performance of some code acquisition schemes are studied in the down... more Abstract| In this paper, the performance of some code acquisition schemes are studied in the downlink of DS-CDMA systems. The conventional matched lter, the minimum variance method, the MUSIC algorithms and the eigenvector method based delay acquisition schemes are studied in a frequency-selective fading channel. The three last algorithms are based on di erent estimation schemes for the inverse of the sample-covariance matrix. Based on the results, the minimum variance based method can be used to improve the acquisition performance in comparison to the conventional non-coherent matched lter method. The MUSIC algorithm becomes useless in highly loaded systems. The best performance, however, was obtained by using a longer despreading interval in the conventional delay estimator. Unfortunately, it would require either unmodulated pilot channel or a control channel with lower data rate, which may not be available in all applications.
IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference, 2008
Opportunistic user allocation and multiple antenna transmission provide significant performance e... more Opportunistic user allocation and multiple antenna transmission provide significant performance enhancement in future wireless communication systems. In this paper, theoretical outage capacity analysis of user allocation in downlink orthogonal frequency division multiple access (OFDMA) with multiple antenna transmission and limited feedback is presented. Several multiple antenna transmission schemes are considered in OFDMA system, where resources are allocated according to the resource-wise signal-to-noise ratio (SNR) quantization. Performance results show that the resource-wise one bit feedback from few uncorrelated resources provides significant allocation gain. Numerical results based on the analysis are compared to those obtained by computer simulations to validate the correctness of the proposed analysis.
The signal and threshold quantization effects on the performance of the total-power radiometer de... more The signal and threshold quantization effects on the performance of the total-power radiometer detector are studied. The goal is to define the sufficient number of quantization bits to maintain acceptable performance when the noise level estimate is assumed to be perfect. In addition, we study the effects of the dynamic range related to noise level. The simulations illustrate that the selection of the dynamic range affects the performance enormously. The noise should not be allowed to be saturated. If the dynamic range is set correctly, 4 bits is a sufficient number for signal quantization.
ABSTRACT This letter introduces diagnostic impulse-detection methods in general, and, based on th... more ABSTRACT This letter introduces diagnostic impulse-detection methods in general, and, based on those, presents three iterative impulse detectors for communication receivers with an antenna array. These detectors are implemented either in a backward or forward search mode. The forward methods are shown to perform better. They can detect all the impulses, even though 90% of all the samples are corrupted.
This paper proposes practical coordinated linear transmit-receive processing schemes for the upli... more This paper proposes practical coordinated linear transmit-receive processing schemes for the uplink (UL) of multiuser multipleinput multiple-output (MIMO) systems in the time division duplex (TDD) mode. The base station (BS) computes the transmission parameters in a centralized manner and employs downlink (DL) pilot signals to convey the information of the beam selection and beamformers to be used by the terminals. When coexisting with the DL transmit-receive zero forcing, the precoded DL demodulation pilots can be reused for UL beam allocation so that no additional pilot overhead is required. Furthermore, the locally available channel state information (CSI) of the effective MIMO channel is sufficient for the terminals to perform transmit power and rate allocation independently. In order to reduce the UL pilot overhead as well, we propose reusing the precoded UL demodulation pilots in turn for partial CSI sounding. The achievable sum rate of the system is evaluated in time-varying fading channels and with channel estimation. According to the results, the proposed UL transmission strategy provides increased rates compared to single-user MIMO transmission combined with user selection as well as to UL antenna selection transmission, without being sensitive to CSI uncertainty.
It is foreseen that a single (wideband) air interface mode is not sufficient for achieving the hi... more It is foreseen that a single (wideband) air interface mode is not sufficient for achieving the high spectral efficiency targets set for next generation wireless system. A dual-bandwidth approach is adapted to simultaneously provide wide coverage and high capacity in a large range of different operating envi-ronments. In this paper, hybrid diversity-multiplexing scheme, where Space-time Turbo Coded Modulation (STTuCM) and layered space-time architectures are combined, is used as the air interface for the wide area communication to provide high spectral efficiency and robustness against spatial fading corre-lation. A system level performance study with different radio resource allocation functionalities applied to the proposed low bandwidth STTuCM orthogonal frequency division multiplexing air interface concept is conducted. The simulation results from the developed system level simulator indicate that the dynamic channel allocation (DCA) results in far better performance than the ran...
The least squares (LS) channel estimation algorithm for a multiple-input multiple-output (MIMO) s... more The least squares (LS) channel estimation algorithm for a multiple-input multiple-output (MIMO) system with orthog-onal frequency division multiplexing (OFDM) is considered in this paper. Two architectures for the algorithm are pre-sented and the architectures are implemented using fixed point arithmetic. The minimum word lengths for the imple-mentations are determined through computer simulations for 2 × 2 and 4 × 4 MIMO systems with quadrature phase-shift keying (QPSK) modulation. Field-programmable gate array (FPGA) synthesis simulation is done for the architec-tures using the obtained word lengths which provides com-plexity and latency results. The algorithm implementations are shown to consume reasonably small amount of hardware resources.
VTC '98. 48th IEEE Vehicular Technology Conference. Pathway to Global Wireless Revolution (Cat. No.98CH36151), 1998
The performance of the multi-code (MC) access system with one processing gain and the multiple pr... more The performance of the multi-code (MC) access system with one processing gain and the multiple processing gain (MPG) access for asynchronous multirate code-division multiple-access (CDMA) systems are considered. The bit error rates (BER) of the decorrelating, parallel interference canceler (PIC) and groupwise serial interference canceler (GSIC) with either the PIC or decorrelator within the group are compared. The results show
VTC '98. 48th IEEE Vehicular Technology Conference. Pathway to Global Wireless Revolution (Cat. No.98CH36151), 1998
The decorrelating multiuser detector for asynchronous multirate multiuser code-division multiple-... more The decorrelating multiuser detector for asynchronous multirate multiuser code-division multiple-access (CDMA) systems is analyzed. A multirate CDMA system model able to fit several system concepts in the same framework is presented. The performance of the multi-code (MC) system with one processing gain and a multiple processing gain (MPG) system is compared. Lower bounds for the expected value of the asymptotic multiuser efficiency of a synchronous multirate CDMA system with three effective users are derived for a system with one and two processing gains. The numerical results show that the performance of the decorrelating detector for MC and MPG systems do not differ significantly
Proceedings of 6th International Symposium on Personal, Indoor and Mobile Radio Communications, 1995
For synchronous CDMA systems the decorrelating multiuser detector is the inverse of the correlati... more For synchronous CDMA systems the decorrelating multiuser detector is the inverse of the correlation matrix of the signature waveforms. The noise-whitening multiuser detector is the inverse of the Cholesky factor of the correlation matrix. If the number of users or the signature signals changes, the detectors must be recomputed. The paper introduces order-recursive algorithms for detector update. The algorithms compute
The inclusion of groupwise interference cancellation techniques into WCDMA uplink receivers is st... more The inclusion of groupwise interference cancellation techniques into WCDMA uplink receivers is studied in this paper. Emerging third generation WCDMA signal structures for multirate transmission are utilized along with necessary uplink techniques, namely antenna diversity reception, transmitter power control and signal-to-interference ratio (SIR) estimation. A groupwise serial interference cancellation (GSIC) technique suitable for WCDMA systems using long spreading sequences is
11th IEEE International Symposium on Personal Indoor and Mobile Radio Communications. PIMRC 2000. Proceedings (Cat. No.00TH8525), 2000
... PIC Receiver Kimmo Kansanen Jianke Fan Markku Juntti Matti Latva-aho University of Oulu, Cent... more ... PIC Receiver Kimmo Kansanen Jianke Fan Markku Juntti Matti Latva-aho University of Oulu, Centre for Wireless Communications PO Box 4500, FIN-90014 University of Oulu, Finland tel. f358 8 553 2833, fax. f358 8 553 2845 { kimmo . kansanen, fan. jianke,markku. junt ti,mat t i ...
2004 IEEE 15th International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE Cat. No.04TH8754), 2004
We evaluate the performance of single- and multi-antenna multi-carrier code division multiple acc... more We evaluate the performance of single- and multi-antenna multi-carrier code division multiple access (MC-CDMA) downlink (base station to mobile terminal) systems in multi-cell environments. We first propose a minimum mean square error (MMSE) filter for a single input single output (SISO) MC-CDMA downlink system. Then, we apply it to a SIMO (single input multiple output) system with a conventional turbo
The 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, 2002
A design method for recursive space-time trellis codes and parallel concatenated space-time turbo... more A design method for recursive space-time trellis codes and parallel concatenated space-time turbo coded modulation was recently proposed as a new framework for building optimized, low-complexity, large equivalent constraint-length space-time trellis codes. In this paper the distance spectrum interpretation of the space-time turbo coded modulation is introduced to evaluate the union bound on the frame error rate over fast fading channels. The distance spectrum gives a good insight on the importance of multiplicities in the space-time coding design. Derived bounds are in some cases very tight and provide a designer with the practical tool for further optimization of the constituent space-time trellis codes within the space-time turbo coded modulation framework. Some interesting examples of the convergence of the sub-optimal iterative decoding were also presented.
We propose a new bandwidth and power efficient signaling scheme for achieving high data rates ove... more We propose a new bandwidth and power efficient signaling scheme for achieving high data rates over wideband radio channels exploiting bandwidth efficient OFDM modulation, multiple transmit and receive antennas and large frequency selectivity offered in typical low mobility indoor environments. Due to its maximum achievable transmit diversity gain and large coding gain, space-frequency turbo coded modulation strongly outperforms other space-frequency coding schemes recently proposed in literature. We also propose a simple way of combining space-frequency coding with OFDM delay diversity as a cost-effective method for further bandwidth efficiency increase by exploiting more than two antennas at the transmitter.
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Papers by Markku Juntti