Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990386
M. R. Gholami, S. Gezici, E. Strom, M. Rydstrom
This paper addresses the problem of single node positioning in cooperative network using hybrid two-way time-of-arrival and time-difference-of-arrival where, the turn-around time at the target node is unknown. Considering the turn-around time as a nuisance parameter, the derived maximum likelihood estimator (MLE) brings a difficult global optimization problem due to local minima in the cost function of the MLE. To avoid drawbacks in solving the MLE, we obtain a linear two-step estimator using non-linear pre-processing which is algebraic and closed-form in each step. To compare different methods, Cramér-Rao lower bound (CRLB) is derived. Simulation results confirm that the proposed linear estimator attains the CRLB for sufficiently high signal-to-noise ratios.
{"title":"Positioning algorithms for cooperative networks in the presence of an unknown turn-around time","authors":"M. R. Gholami, S. Gezici, E. Strom, M. Rydstrom","doi":"10.1109/SPAWC.2011.5990386","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990386","url":null,"abstract":"This paper addresses the problem of single node positioning in cooperative network using hybrid two-way time-of-arrival and time-difference-of-arrival where, the turn-around time at the target node is unknown. Considering the turn-around time as a nuisance parameter, the derived maximum likelihood estimator (MLE) brings a difficult global optimization problem due to local minima in the cost function of the MLE. To avoid drawbacks in solving the MLE, we obtain a linear two-step estimator using non-linear pre-processing which is algebraic and closed-form in each step. To compare different methods, Cramér-Rao lower bound (CRLB) is derived. Simulation results confirm that the proposed linear estimator attains the CRLB for sufficiently high signal-to-noise ratios.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116713649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990396
I. Bergel, D. Yellin, S. Shamai
We present upper and lower bounds on the achievable average user data rates in the downlink of a one-dimensional Wyner cellular channel model when limited cooperation and linear precoding are employed. These bounds show that the user data rates can be dramatically increased compared to those achievable with non-cooperating cellular systems. Furthermore, the bounds show that near optimal performance can be achieved with a small number of cooperating base stations (BS's) and a simple to implement linear precoding scheme.
{"title":"Linear precoding bounds for the Wyner cellular channel model with limited cooperation","authors":"I. Bergel, D. Yellin, S. Shamai","doi":"10.1109/SPAWC.2011.5990396","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990396","url":null,"abstract":"We present upper and lower bounds on the achievable average user data rates in the downlink of a one-dimensional Wyner cellular channel model when limited cooperation and linear precoding are employed. These bounds show that the user data rates can be dramatically increased compared to those achievable with non-cooperating cellular systems. Furthermore, the bounds show that near optimal performance can be achieved with a small number of cooperating base stations (BS's) and a simple to implement linear precoding scheme.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126140536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990412
Chunhui Liu, Lars Schiefler, A. Schmeink, R. Mathar
It has been shown that energy efficiency can be significantly improved by adaptive multicarrier transmission. When the water-filling strategy is employed, different rates are allocated to subcarriers. However, a large signalling overhead is induced, when the employed allocation scheme must be sent to receivers via signalling. In this paper, to enhance energy efficiency, we propose that a dynamic and symmetric rate is allocated to subcarriers of each user. Thereby, fewer bits are required to express each allocation scheme. The asymptotic limit of induced performance loss is given compared to the water-filling strategy. Furthermore, the proposed strategy brings convenience for heuristic design. Simulations demonstrate that the proposed method achieves higher energy efficiency than the water-filling strategy as allocation schemes are frequently updated in fast time-varying environments.
{"title":"Energy efficiency on real time transmission in multiuser OFDM downlink","authors":"Chunhui Liu, Lars Schiefler, A. Schmeink, R. Mathar","doi":"10.1109/SPAWC.2011.5990412","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990412","url":null,"abstract":"It has been shown that energy efficiency can be significantly improved by adaptive multicarrier transmission. When the water-filling strategy is employed, different rates are allocated to subcarriers. However, a large signalling overhead is induced, when the employed allocation scheme must be sent to receivers via signalling. In this paper, to enhance energy efficiency, we propose that a dynamic and symmetric rate is allocated to subcarriers of each user. Thereby, fewer bits are required to express each allocation scheme. The asymptotic limit of induced performance loss is given compared to the water-filling strategy. Furthermore, the proposed strategy brings convenience for heuristic design. Simulations demonstrate that the proposed method achieves higher energy efficiency than the water-filling strategy as allocation schemes are frequently updated in fast time-varying environments.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125883284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990437
Jawad Rasool, G. Oien
Specifying exact throughput guarantees in wireless systems, carrying real-time traffic, is in the interest of both the network operators and the customers. Based on our previous work, we formulate an optimization problem that aims at maximizing the throughput guarantees offered in a MIMO broadcast channel. We also propose two scheduling algorithms that make use of orthonormal random beamforming, and try to fulfill the throughput guarantees promised to all the mobile users. The scheduling algorithms are designed for two different beamforming scenarios. In the first scenario, random beams are used for all the selected users, whereas transmit beamforming is used for the first selected user in the second scenario. We further propose simple and low complexity adaptive scheduling algorithms that perform significantly better than other well-known scheduling algorithms, in terms of the throughput guarantee violation probability.
{"title":"Scheduling schemes for improved throughput guarantees in MIMO broadcast channels","authors":"Jawad Rasool, G. Oien","doi":"10.1109/SPAWC.2011.5990437","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990437","url":null,"abstract":"Specifying exact throughput guarantees in wireless systems, carrying real-time traffic, is in the interest of both the network operators and the customers. Based on our previous work, we formulate an optimization problem that aims at maximizing the throughput guarantees offered in a MIMO broadcast channel. We also propose two scheduling algorithms that make use of orthonormal random beamforming, and try to fulfill the throughput guarantees promised to all the mobile users. The scheduling algorithms are designed for two different beamforming scenarios. In the first scenario, random beams are used for all the selected users, whereas transmit beamforming is used for the first selected user in the second scenario. We further propose simple and low complexity adaptive scheduling algorithms that perform significantly better than other well-known scheduling algorithms, in terms of the throughput guarantee violation probability.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130162828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990411
D. van Welden, H. Steendam, M. Moeneclaey
In this paper, we propose two ad hoc frequency offset (FO) estimation algorithms in a known symbol padding (KSP) orthogonal frequency-division multiplexing (OFDM) system, where the guard interval is filled with pilot symbols. Besides those time domain pilot symbols, some additional pilot symbols are transmitted on the pilot carriers. The FO is estimated without any channel knowledge. One algorithm operates in the time domain (TD), while the other one operates in the frequency domain (FD). The interference from the unknown data symbols is much smaller in the FD than in the TD, especially for small FOs. As a result, the FD initialization algorithm results in a lower mean squared error (MSE). Both estimation algorithms reach the BER performance of a receiver with perfect knowledge about the FO.
{"title":"Frequency offset estimation for KSP-OFDM","authors":"D. van Welden, H. Steendam, M. Moeneclaey","doi":"10.1109/SPAWC.2011.5990411","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990411","url":null,"abstract":"In this paper, we propose two ad hoc frequency offset (FO) estimation algorithms in a known symbol padding (KSP) orthogonal frequency-division multiplexing (OFDM) system, where the guard interval is filled with pilot symbols. Besides those time domain pilot symbols, some additional pilot symbols are transmitted on the pilot carriers. The FO is estimated without any channel knowledge. One algorithm operates in the time domain (TD), while the other one operates in the frequency domain (FD). The interference from the unknown data symbols is much smaller in the FD than in the TD, especially for small FOs. As a result, the FD initialization algorithm results in a lower mean squared error (MSE). Both estimation algorithms reach the BER performance of a receiver with perfect knowledge about the FO.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130470165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990426
Daniel Sacristán-Murga, M. Payaró, A. Pascual-Iserte
In this paper we deal with amultiple-input multiple-output (MIMO) multiuser broadcast channel (BC) featuring linear precoding at the transmitter. The design of such precoder is performed according to the channel state information (CSI) sent by the different users through parallel feedback links. A general feedback framework based on the quantization of each user's channel Gram matrix is presented. Once the channel Gram matrices are available at the transmitter, they can be used to compute equivalent triangular MIMO channels for which the optimum precoder is calculated. As an application of this framework, a robust precoder design that takes into account errors in the CSI that are originated, for example, from the finite-bit quantization process applied in the feedback, is also presented. Finally the benefits of the proposed robust strategy are evaluated by means of numerical simulations.
{"title":"Robust linear precoding for MSE minimization in MIMO broadcast systems with channel Gram matrix feedback","authors":"Daniel Sacristán-Murga, M. Payaró, A. Pascual-Iserte","doi":"10.1109/SPAWC.2011.5990426","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990426","url":null,"abstract":"In this paper we deal with amultiple-input multiple-output (MIMO) multiuser broadcast channel (BC) featuring linear precoding at the transmitter. The design of such precoder is performed according to the channel state information (CSI) sent by the different users through parallel feedback links. A general feedback framework based on the quantization of each user's channel Gram matrix is presented. Once the channel Gram matrices are available at the transmitter, they can be used to compute equivalent triangular MIMO channels for which the optimum precoder is calculated. As an application of this framework, a robust precoder design that takes into account errors in the CSI that are originated, for example, from the finite-bit quantization process applied in the feedback, is also presented. Finally the benefits of the proposed robust strategy are evaluated by means of numerical simulations.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132100004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990458
K. Nordhausen, E. Ollila, H. Oja
For assessing the separation performance (quality and accuracy) of ICA estimators, several performance indices have been introduced in the literature. The purpose of this note is to outline, review and study the properties of performance indices as well as propose some new ones. Special emphasis is put on the properties that such performance indices ought to satisfy. We categorize the indices in two separate groups that differ in the approaches they deploy in measuring the closeness of the achieved source separation to the ideal case and point out some inherent relations between the indices in these categories.
{"title":"On the performance indices of ICA and blind source separation","authors":"K. Nordhausen, E. Ollila, H. Oja","doi":"10.1109/SPAWC.2011.5990458","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990458","url":null,"abstract":"For assessing the separation performance (quality and accuracy) of ICA estimators, several performance indices have been introduced in the literature. The purpose of this note is to outline, review and study the properties of performance indices as well as propose some new ones. Special emphasis is put on the properties that such performance indices ought to satisfy. We categorize the indices in two separate groups that differ in the approaches they deploy in measuring the closeness of the achieved source separation to the ideal case and point out some inherent relations between the indices in these categories.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130473163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990376
Huang Yan, Peng Hua, Li Qiang
Aiming at the difficulties of blind doppler parameters estimation for QAM signals in the satellite communication on-the-move (SCOTM) system, a new joint algorithm of blind doppler frequency and doppler-rate estimation based on cyclic-statistical tests and phase difference is proposed. By detecting one of the cyclic frequencies of QAM signals, located at the quartic frequency offset, doppler frequency is effectively estimated, meanwhile, the data division method is exploited to calculate the doppler-rate. Finally, phase lock loop (PLL) is proposed to make the estimation more accurately. All-sided Monte Carlo simulations are employed to confirm the theoretical analysis, simulation results indicate that this algorithm can track time-varying frequency of the QAM signals accurately.
{"title":"New joint algorithm of blind doppler parameters estimation for high-order QAM signals","authors":"Huang Yan, Peng Hua, Li Qiang","doi":"10.1109/SPAWC.2011.5990376","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990376","url":null,"abstract":"Aiming at the difficulties of blind doppler parameters estimation for QAM signals in the satellite communication on-the-move (SCOTM) system, a new joint algorithm of blind doppler frequency and doppler-rate estimation based on cyclic-statistical tests and phase difference is proposed. By detecting one of the cyclic frequencies of QAM signals, located at the quartic frequency offset, doppler frequency is effectively estimated, meanwhile, the data division method is exploited to calculate the doppler-rate. Finally, phase lock loop (PLL) is proposed to make the estimation more accurately. All-sided Monte Carlo simulations are employed to confirm the theoretical analysis, simulation results indicate that this algorithm can track time-varying frequency of the QAM signals accurately.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133982344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990465
J. Bhatti, N. Noels, M. Moeneclaey
We present two phase noise estimation algorithms for single-carrier burst communications. The first and second estimation techniques (denoted as PEA1 and PEA2 respectively) are based on a truncated discrete cosine transform (DCT) basis expansion of the phase noise and of the corresponding phasor, respectively and do not require any knowledge of the phase noise statistics. An initial pilot-based estimate is iteratively improved by means of the expectation-maximization algorithm, yielding a soft-decision-directed phase noise estimate. The performances of PEA1 and PEA2 are compared in terms of the mean-square phase error and bit-error rate. Numerical results show that PEA2 outperforms PEA1 for practical values of the signal-to-noise ratio.
{"title":"Algorithms for iterative phase noise estimation based on a truncated DCT expansion","authors":"J. Bhatti, N. Noels, M. Moeneclaey","doi":"10.1109/SPAWC.2011.5990465","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990465","url":null,"abstract":"We present two phase noise estimation algorithms for single-carrier burst communications. The first and second estimation techniques (denoted as PEA1 and PEA2 respectively) are based on a truncated discrete cosine transform (DCT) basis expansion of the phase noise and of the corresponding phasor, respectively and do not require any knowledge of the phase noise statistics. An initial pilot-based estimate is iteratively improved by means of the expectation-maximization algorithm, yielding a soft-decision-directed phase noise estimate. The performances of PEA1 and PEA2 are compared in terms of the mean-square phase error and bit-error rate. Numerical results show that PEA2 outperforms PEA1 for practical values of the signal-to-noise ratio.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133267619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990464
M. Mardani, Seung-Jun Kim, G. Giannakis
Cross-layer design of medium access, routing and congestion control is considered for multi-hop wireless ad hoc networks with random access. A network utility maximization frame-work is adopted to jointly optimize link persistence probabilities, per-link flow rates, and end-to-end throughput. The optimization problem with flow conservation and probabilistic random access constraints is inherently non-convex. A series of convex surrogate problems is thus formulated using a successive convex approximation technique. A distributed algorithm is then developed based on the dual method, which is convergent to a (locally) optimal solution. To much practical appeal, solutions to the subproblems corresponding to different layers of the protocol stack, are obtained at each node with very low computational complexity. Numerical tests verify the proposed novel design.
{"title":"Optimization of wireless multi-hop networks with random access","authors":"M. Mardani, Seung-Jun Kim, G. Giannakis","doi":"10.1109/SPAWC.2011.5990464","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990464","url":null,"abstract":"Cross-layer design of medium access, routing and congestion control is considered for multi-hop wireless ad hoc networks with random access. A network utility maximization frame-work is adopted to jointly optimize link persistence probabilities, per-link flow rates, and end-to-end throughput. The optimization problem with flow conservation and probabilistic random access constraints is inherently non-convex. A series of convex surrogate problems is thus formulated using a successive convex approximation technique. A distributed algorithm is then developed based on the dual method, which is convergent to a (locally) optimal solution. To much practical appeal, solutions to the subproblems corresponding to different layers of the protocol stack, are obtained at each node with very low computational complexity. Numerical tests verify the proposed novel design.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127494597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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