Pub Date : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625254
Peter J. Smith, Mansoor Shafit, L. Garth
In this paper we consider the performance of an adaptive MIMO SVD (singular value decomposition) transmission scheme operating in a cellular environment. In particular we consider the impact of inter-cell interference on the performance of an adaptive MIMO system. Inter-cell interference is always present in a cellular system. However, its value may be controlled by the type of cellular layout, i.e., the number of sectors and the frequency reuse pattern. In this paper we consider a number of cellular layouts and consider the impact of the resulting SINR on the constellation sizes that can be supported, the BER, etc. The primary metric used for our performance analysis is the error free transmission rate, and this is derived for the adaptive MIMO SVD system. For the cellular scenarios considered, we find that the effect of interference is considerable and the performance of the adaptive MIMO SVD scheme is only marginally better than that provided by conventional diversity methods
{"title":"Performance analysis for adaptive MIMO SVD transmission in a cellular system","authors":"Peter J. Smith, Mansoor Shafit, L. Garth","doi":"10.1109/AUSCTW.2006.1625254","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625254","url":null,"abstract":"In this paper we consider the performance of an adaptive MIMO SVD (singular value decomposition) transmission scheme operating in a cellular environment. In particular we consider the impact of inter-cell interference on the performance of an adaptive MIMO system. Inter-cell interference is always present in a cellular system. However, its value may be controlled by the type of cellular layout, i.e., the number of sectors and the frequency reuse pattern. In this paper we consider a number of cellular layouts and consider the impact of the resulting SINR on the constellation sizes that can be supported, the BER, etc. The primary metric used for our performance analysis is the error free transmission rate, and this is derived for the adaptive MIMO SVD system. For the cellular scenarios considered, we find that the effect of interference is considerable and the performance of the adaptive MIMO SVD scheme is only marginally better than that provided by conventional diversity methods","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128253133","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 : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625256
R. Milner, L.K. Rasmussesn
In iterative decoding it is well accepted that extrinsic information is to be exchanged between full-complexity soft-input, soft-output constituent decoder components. It is, however, still an open problem to determine the optimal information for exchange between reduced complexity decoder components that are only approximating posterior probabilities. In this paper we investigate the use of weighted extrinsic feedback in iterative multiuser decoding for coded code-division multiple-access (CDMA) systems. The case of no extrinsic feedback corresponds to the conventional approach of exchanging extrinsic information, while full extrinsic feedback corresponds to exchanging a posteriori information. Weighted extrinsic feedback offers a trade-off between the two extreme cases, which can provide significant improvements. These improvements are demonstrated through simulation of an iterative multiuser decoder using parallel interference cancellation as the soft-input, soft-output multiuser detector
{"title":"Weighted extrinsic feedback in the iterative multiuser decoding of coded CDMA","authors":"R. Milner, L.K. Rasmussesn","doi":"10.1109/AUSCTW.2006.1625256","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625256","url":null,"abstract":"In iterative decoding it is well accepted that extrinsic information is to be exchanged between full-complexity soft-input, soft-output constituent decoder components. It is, however, still an open problem to determine the optimal information for exchange between reduced complexity decoder components that are only approximating posterior probabilities. In this paper we investigate the use of weighted extrinsic feedback in iterative multiuser decoding for coded code-division multiple-access (CDMA) systems. The case of no extrinsic feedback corresponds to the conventional approach of exchanging extrinsic information, while full extrinsic feedback corresponds to exchanging a posteriori information. Weighted extrinsic feedback offers a trade-off between the two extreme cases, which can provide significant improvements. These improvements are demonstrated through simulation of an iterative multiuser decoder using parallel interference cancellation as the soft-input, soft-output multiuser detector","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133549589","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 : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625269
Z. Krusevac, R. Kennedy, P. Rapajic
This paper shows the existence of the optimal training, in terms of achievable mutual information rate, for an output feedback implicit estimator for finite-state Markov communication channels. Implicit (blind) estimation is based on a measure of how modified is the input distribution when filtered by the channel transfer function and it is shown that there is no modification of an input distribution with maximum entropy rate. Input signal entropy rate reduction enables implicit (blind) channel process estimation, but decreases information transmission rate. The optimal input entropy rate (optimal implicit training rate) which achieves the maximum mutual information rate, is found
{"title":"Implicit channel estimation for ML sequence detection over finite-state Markov communication channels","authors":"Z. Krusevac, R. Kennedy, P. Rapajic","doi":"10.1109/AUSCTW.2006.1625269","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625269","url":null,"abstract":"This paper shows the existence of the optimal training, in terms of achievable mutual information rate, for an output feedback implicit estimator for finite-state Markov communication channels. Implicit (blind) estimation is based on a measure of how modified is the input distribution when filtered by the channel transfer function and it is shown that there is no modification of an input distribution with maximum entropy rate. Input signal entropy rate reduction enables implicit (blind) channel process estimation, but decreases information transmission rate. The optimal input entropy rate (optimal implicit training rate) which achieves the maximum mutual information rate, is found","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130319250","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 : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625249
A. Guillén i Fàbregas, Qi Tang
We study an M-ary block-erasure channel with B blocks, where with probability ε a block of L coded symbols is erased. We study the behavior of the error probability of coded systems over such channels, and show that, if the code is diversitywise maximum-distance separable, its word error probability is equal to the outage probability, which admits a very simple expression. This paper is intended to complement the error probability analysis in previous work by Lapidoth and shed some light on the design of coding schemes for nonergodic channels.
{"title":"Coding in the Block-Erasure Channel","authors":"A. Guillén i Fàbregas, Qi Tang","doi":"10.1109/AUSCTW.2006.1625249","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625249","url":null,"abstract":"We study an M-ary block-erasure channel with B blocks, where with probability ε a block of L coded symbols is erased. We study the behavior of the error probability of coded systems over such channels, and show that, if the code is diversitywise maximum-distance separable, its word error probability is equal to the outage probability, which admits a very simple expression. This paper is intended to complement the error probability analysis in previous work by Lapidoth and shed some light on the design of coding schemes for nonergodic channels.","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124769068","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 : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625255
G. Cresp, H. H. Dam, H. Zepernick
The number of spreading sequences required for direct sequence code division multiple access (DS-CDMA) systems depends on the number of simultaneous users on the channel. The correlation properties of the sequences used affect the bit error rate of the system. Often a sequence family provides more sequences than are required and in many cases the selection of the employed sequences is a computationally intensive task. In this paper, a branch and bound algorithm is presented to optimise the subset of available sequences, given the required subset size. In contrast to previous approaches, the resulting subset is guaranteed to be optimal. Numerical results are presented to demonstrate the improved performance of this algorithm over previous work
{"title":"Subset family design using a branch and bound technique","authors":"G. Cresp, H. H. Dam, H. Zepernick","doi":"10.1109/AUSCTW.2006.1625255","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625255","url":null,"abstract":"The number of spreading sequences required for direct sequence code division multiple access (DS-CDMA) systems depends on the number of simultaneous users on the channel. The correlation properties of the sequences used affect the bit error rate of the system. Often a sequence family provides more sequences than are required and in many cases the selection of the employed sequences is a computationally intensive task. In this paper, a branch and bound algorithm is presented to optimise the subset of available sequences, given the required subset size. In contrast to previous approaches, the resulting subset is guaranteed to be optimal. Numerical results are presented to demonstrate the improved performance of this algorithm over previous work","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124221815","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 : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625277
C. Withers
Foschini gave a lower bound for the channel capacity of an N-transmit M-receive antenna system in a Rayleigh fading environment with independence at both transmitters and receivers. We show that this bound is approximately normal and that its distribution has a non-standard Edgeworth-type expansion. This allows one to obtain non-standard Cornish-Fisher expansions for its percentiles and so obtain its distribution and outage levels for given probabilities
{"title":"The distribution and percentiles of Foschini's lower bound for channel capacity","authors":"C. Withers","doi":"10.1109/AUSCTW.2006.1625277","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625277","url":null,"abstract":"Foschini gave a lower bound for the channel capacity of an N-transmit M-receive antenna system in a Rayleigh fading environment with independence at both transmitters and receivers. We show that this bound is approximately normal and that its distribution has a non-standard Edgeworth-type expansion. This allows one to obtain non-standard Cornish-Fisher expansions for its percentiles and so obtain its distribution and outage levels for given probabilities","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"389 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122856155","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 : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625265
W. Cowley, M.S.C. Ho
Iterative receivers can provide excellent coding gain which allows performance close to channel capacity limits. Recent extensions of the basic iterative decoding strategy have enabled "front-end" receiver synchronisation tasks to be included in the iterative loop. However in channels with rapid phase and frequency variations, the lower signal to noise ratios of iterative systems may still pose significant synchronisation difficulties. This paper addresses a channel where Doppler offsets create specific challenges in a serial concatenated convolutional code (SCCC) system. New signal constellations and sub-block decoding techniques are proposed which overcome these problems.
{"title":"Transmission Design for Doppler- Varying Channels","authors":"W. Cowley, M.S.C. Ho","doi":"10.1109/AUSCTW.2006.1625265","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625265","url":null,"abstract":"Iterative receivers can provide excellent coding gain which allows performance close to channel capacity limits. Recent extensions of the basic iterative decoding strategy have enabled \"front-end\" receiver synchronisation tasks to be included in the iterative loop. However in channels with rapid phase and frequency variations, the lower signal to noise ratios of iterative systems may still pose significant synchronisation difficulties. This paper addresses a channel where Doppler offsets create specific challenges in a serial concatenated convolutional code (SCCC) system. New signal constellations and sub-block decoding techniques are proposed which overcome these problems.","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116636815","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 : 2006-05-08DOI: 10.1109/AUSCTW.2006.1625264
Muhammad Naeem Bacha, J. Evans, S. Hanly
We consider the information theoretic limits of the uplink in a MIMO cellular network with two types of macrodiversity. In the first case, the whole network acts as a multi-access channel where every base station antenna array is part of a central receiver (global macrodiversity). In the second case, we partition the network into clusters of cooperating base stations (local macrodiversity) thereby eliminating the growth in complexity at the receiver with network size. Macrodiversity is shown to provide very significant gains in sum capacity over single cell processing schemes where co-channel interference is the dominant impairment. We also explore the rate at which the sum capacity of the local macrodiversity scheme approaches that of global macrodiversity as the cluster size increases.
{"title":"On the Capacity of MIMO Cellular Networks with Macrodiversity","authors":"Muhammad Naeem Bacha, J. Evans, S. Hanly","doi":"10.1109/AUSCTW.2006.1625264","DOIUrl":"https://doi.org/10.1109/AUSCTW.2006.1625264","url":null,"abstract":"We consider the information theoretic limits of the uplink in a MIMO cellular network with two types of macrodiversity. In the first case, the whole network acts as a multi-access channel where every base station antenna array is part of a central receiver (global macrodiversity). In the second case, we partition the network into clusters of cooperating base stations (local macrodiversity) thereby eliminating the growth in complexity at the receiver with network size. Macrodiversity is shown to provide very significant gains in sum capacity over single cell processing schemes where co-channel interference is the dominant impairment. We also explore the rate at which the sum capacity of the local macrodiversity scheme approaches that of global macrodiversity as the cluster size increases.","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124788337","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 : 2006-05-07DOI: 10.1109/VETECS.2006.1683084
Y. Hong, A. G. Fàbregas
New space-time trellis codes with 4-PSK, 8-PSK and 16-QAM for two transmit antennas in slow fading channels are proposed in this paper. The codes are designed specifically to minimize the frame error probability. The performance of the proposed codes with various memory orders and receive antennas is evaluated by simulation. It is shown that the proposed codes outperform previously known codes
{"title":"New space-time trellis codes for slow fading channels","authors":"Y. Hong, A. G. Fàbregas","doi":"10.1109/VETECS.2006.1683084","DOIUrl":"https://doi.org/10.1109/VETECS.2006.1683084","url":null,"abstract":"New space-time trellis codes with 4-PSK, 8-PSK and 16-QAM for two transmit antennas in slow fading channels are proposed in this paper. The codes are designed specifically to minimize the frame error probability. The performance of the proposed codes with various memory orders and receive antennas is evaluated by simulation. It is shown that the proposed codes outperform previously known codes","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131760842","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}
Most existing techniques for space time block coding (STBC) systems have assumed full decorrelated radio channels which may not be the case in practice. In this paper a subspace based approach of semi-blind channel estimation is proposed for precoded STBC systems, in which multiple-input multiple-output (MIMO) channels are partially correlated. By carefully designing the transceiver of the precoded STBC systems, correlated MIMO channels (where correlation is due to antenna geometry) can be converted to full independent MIMO channels. Then a conventional subspace based channel estimation method is applied to such precoded STBC systems. Simulation results demonstrate the performance of the proposed algorithm
{"title":"Semi-blind channel estimation for precoded STBC systems over correlated MIMO channels","authors":"Z. Ding, T. Abhayapala, D. Ward","doi":"10.1049/IC:20050378","DOIUrl":"https://doi.org/10.1049/IC:20050378","url":null,"abstract":"Most existing techniques for space time block coding (STBC) systems have assumed full decorrelated radio channels which may not be the case in practice. In this paper a subspace based approach of semi-blind channel estimation is proposed for precoded STBC systems, in which multiple-input multiple-output (MIMO) channels are partially correlated. By carefully designing the transceiver of the precoded STBC systems, correlated MIMO channels (where correlation is due to antenna geometry) can be converted to full independent MIMO channels. Then a conventional subspace based channel estimation method is applied to such precoded STBC systems. Simulation results demonstrate the performance of the proposed algorithm","PeriodicalId":206040,"journal":{"name":"2006 Australian Communications Theory Workshop","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121439825","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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