Pub Date : 2011-05-17DOI: 10.1109/CWIT.2011.5872128
Chen-Hsiang Feng, Danilo Silva, F. Kschischang
Lattice network coding is recently proposed as a practical implementation of Nazer-Gastpar's compute-and-forward relaying strategy. Previous investigation of lattice network coding is mainly over finite fields. In this paper, we extend lattice network coding from finite fields to finite rings. In addition to having its own theoretical interest, this extension provides an alternative viewpoint of Nazer-Gastpar's relaying strategy and this extension expands the design space of lattice network codes. In particular, we show that this extension enables the use of complex Construction D to design lattice network codes, leading to potentially higher encoder rates.
{"title":"Lattice network coding over finite rings","authors":"Chen-Hsiang Feng, Danilo Silva, F. Kschischang","doi":"10.1109/CWIT.2011.5872128","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872128","url":null,"abstract":"Lattice network coding is recently proposed as a practical implementation of Nazer-Gastpar's compute-and-forward relaying strategy. Previous investigation of lattice network coding is mainly over finite fields. In this paper, we extend lattice network coding from finite fields to finite rings. In addition to having its own theoretical interest, this extension provides an alternative viewpoint of Nazer-Gastpar's relaying strategy and this extension expands the design space of lattice network codes. In particular, we show that this extension enables the use of complex Construction D to design lattice network codes, leading to potentially higher encoder rates.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128454773","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872131
E. Karamad, R. Adve
Centralized algorithms for relay selection and power allocation in cooperative networks have been widely considered in the literature. As effective as the proposed algorithms are, the complexity of centralized implementation and feedback required to communicate the required channel state information makes these solutions impractical. Here we investigate, in terms of the achievable rates for the nodes, relaying and power allocation for cooperative networks and consider the effects of partial channel state information. We first consider 1-bit knowledge of relevant channels followed by the multi-bit case. We also consider the case of multiple sources wherein relay resources must be sub-divided amongst the sources.
{"title":"Optimal rates for decode-and-forward cooperative networks with partial CSI","authors":"E. Karamad, R. Adve","doi":"10.1109/CWIT.2011.5872131","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872131","url":null,"abstract":"Centralized algorithms for relay selection and power allocation in cooperative networks have been widely considered in the literature. As effective as the proposed algorithms are, the complexity of centralized implementation and feedback required to communicate the required channel state information makes these solutions impractical. Here we investigate, in terms of the achievable rates for the nodes, relaying and power allocation for cooperative networks and consider the effects of partial channel state information. We first consider 1-bit knowledge of relevant channels followed by the multi-bit case. We also consider the case of multiple sources wherein relay resources must be sub-divided amongst the sources.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125313622","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872139
Shuangshuang Han, C. Tellambura
This paper provides the equivalent maximum likelihood (ML) detector at the destination of multi-branch dual-hop multiple-input multiple-output (MIMO) relay networks. Complexity-efficient detections by extending both the complexity-efficient sphere decoder (CSD) and the fixed complexity sphere decoder are proposed. Comparing to the direct link and the cooperative partial detection, our detection method based on the CSD shows the almost-fixed, reduced complexity at a negligible performance loss. Although detect-and-forward relaying is the main focus, this detection also performs well in amplify-and-forward relaying. The simulation results show that the CSD performs nearly optimal ML performance, while keeping the complexity of MIMO relay detection fixed and reduced, making this algorithm suitable for hardware implementation.
{"title":"Complexity-efficient detection for MIMO relay networks","authors":"Shuangshuang Han, C. Tellambura","doi":"10.1109/CWIT.2011.5872139","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872139","url":null,"abstract":"This paper provides the equivalent maximum likelihood (ML) detector at the destination of multi-branch dual-hop multiple-input multiple-output (MIMO) relay networks. Complexity-efficient detections by extending both the complexity-efficient sphere decoder (CSD) and the fixed complexity sphere decoder are proposed. Comparing to the direct link and the cooperative partial detection, our detection method based on the CSD shows the almost-fixed, reduced complexity at a negligible performance loss. Although detect-and-forward relaying is the main focus, this detection also performs well in amplify-and-forward relaying. The simulation results show that the CSD performs nearly optimal ML performance, while keeping the complexity of MIMO relay detection fixed and reduced, making this algorithm suitable for hardware implementation.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114740920","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872113
Lu Cui, A. Eckford
A new timing channel, known as the delay selector channel (DSC), is proposed as an abstract model for applications with timing noise. In this model, channel inputs are delayed by a random amount, and delayed transmissions are summed at the output. Molecular communication is discussed as a principal application of the DSC, since the channel mimics the propagation and reception of molecules under Brownian motion. In this paper, the DSC is described in detail, and a closed-form lower bound is given on capacity.
{"title":"The delay selector channel: Definition and capacity bounds","authors":"Lu Cui, A. Eckford","doi":"10.1109/CWIT.2011.5872113","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872113","url":null,"abstract":"A new timing channel, known as the delay selector channel (DSC), is proposed as an abstract model for applications with timing noise. In this model, channel inputs are delayed by a random amount, and delayed transmissions are summed at the output. Molecular communication is discussed as a principal application of the DSC, since the channel mimics the propagation and reception of molecules under Brownian motion. In this paper, the DSC is described in detail, and a closed-form lower bound is given on capacity.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129007580","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872138
J. Chu, A. Eckford, R. Adve
A distributed optimization algorithm is presented for resource allocation in wireless relay networks. This algorithm is particularly useful in multiple-source, multiple-relay wireless networks employing fractional cooperation, in which each relay contributes only a fraction of its resources to each source; in this case, the algorithm is used to find the optimal fractions. The advantage of this distributed algorithm is to permit optimization in a large network, even though each node is only aware of the local topology of the network. Examples and simulation results are presented, illustrating the use of this algorithm.
{"title":"Distributed optimization of the Bhattacharyya parameter in wireless relay networks","authors":"J. Chu, A. Eckford, R. Adve","doi":"10.1109/CWIT.2011.5872138","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872138","url":null,"abstract":"A distributed optimization algorithm is presented for resource allocation in wireless relay networks. This algorithm is particularly useful in multiple-source, multiple-relay wireless networks employing fractional cooperation, in which each relay contributes only a fraction of its resources to each source; in this case, the algorithm is used to find the optimal fractions. The advantage of this distributed algorithm is to permit optimization in a large network, even though each node is only aware of the local topology of the network. Examples and simulation results are presented, illustrating the use of this algorithm.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134528463","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872120
B. Babadi, S. Ghassemzadeh, V. Tarokh
In this paper, we study the group randomness of pseudo-random sequences based on shortened first-order Reed-Muller codes and the Gold sequences. In particular, we characterize the empirical spectral distribution of random matrices from shortened first-order Reed-Muller codes. We show that although these sequences have very appealing randomness properties across individual codewords, they do not possess certain group randomness properties of i.i.d. sequences. In other words, the spectral distribution of random matrices from these sequences dramatically differs from that of the random i.i.d. generated matrices. In contrast, Gold sequences manifest the group randomness properties of random i.i.d. sequences. Upper bounds on the Kolmogorov complexity of these sequences are established, and it has been shown that these bounds are much lower than those of the random i.i.d. sequences, when the sequence length is large enough. We discuss the implications of these observations and motivate the need to develop novel randomness tests encompassing both individual and group randomness of sequences.
{"title":"Group randomness properties of pseudo-noise and gold sequences","authors":"B. Babadi, S. Ghassemzadeh, V. Tarokh","doi":"10.1109/CWIT.2011.5872120","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872120","url":null,"abstract":"In this paper, we study the group randomness of pseudo-random sequences based on shortened first-order Reed-Muller codes and the Gold sequences. In particular, we characterize the empirical spectral distribution of random matrices from shortened first-order Reed-Muller codes. We show that although these sequences have very appealing randomness properties across individual codewords, they do not possess certain group randomness properties of i.i.d. sequences. In other words, the spectral distribution of random matrices from these sequences dramatically differs from that of the random i.i.d. generated matrices. In contrast, Gold sequences manifest the group randomness properties of random i.i.d. sequences. Upper bounds on the Kolmogorov complexity of these sequences are established, and it has been shown that these bounds are much lower than those of the random i.i.d. sequences, when the sequence length is large enough. We discuss the implications of these observations and motivate the need to develop novel randomness tests encompassing both individual and group randomness of sequences.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"3 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130249576","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872117
M. Vaezi, M. Vu
We study the cognitive interference channel (CIC) with two transmitters and two receivers, in which the cognitive transmitter non-causally knows the message and codeword of the primary transmitter. We first introduce a discrete memoryless more capable CIC, which is an extension to the more capable broadcast channel (BC). Using superposition coding, an inner bound and an outer bound on its capacity region are proposed. These bounds are then applied to the Gaussian cognitive Z-interference channel (GCZIC), in which only the primary receiver suffers interference. Upon showing that jointly Gaussian distribution maximizes these bounds for the GCZIC, we evaluate them for the GCZIC. The evaluated outer bound appears to be the best outer bound to date on the capacity of the GCZIC in strong interference. More importantly, this outer bound coincides with the inner bound for jaj equation. Thus, we establish the capacity of the GCZIC in this range and show that superposition encoding at the cognitive transmitter and successive decoding at the primary receiver are capacity-achieving.
{"title":"On the capacity of the cognitive Z-interference channel","authors":"M. Vaezi, M. Vu","doi":"10.1109/CWIT.2011.5872117","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872117","url":null,"abstract":"We study the cognitive interference channel (CIC) with two transmitters and two receivers, in which the cognitive transmitter non-causally knows the message and codeword of the primary transmitter. We first introduce a discrete memoryless more capable CIC, which is an extension to the more capable broadcast channel (BC). Using superposition coding, an inner bound and an outer bound on its capacity region are proposed. These bounds are then applied to the Gaussian cognitive Z-interference channel (GCZIC), in which only the primary receiver suffers interference. Upon showing that jointly Gaussian distribution maximizes these bounds for the GCZIC, we evaluate them for the GCZIC. The evaluated outer bound appears to be the best outer bound to date on the capacity of the GCZIC in strong interference. More importantly, this outer bound coincides with the inner bound for jaj equation. Thus, we establish the capacity of the GCZIC in this range and show that superposition encoding at the cognitive transmitter and successive decoding at the primary receiver are capacity-achieving.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131032132","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872125
Shervin Shahidi, F. Alajaji, T. Linder
A channel optimized vector quantizer (COVQ) scheme is studied and evaluated for a recently introduced discrete binary-input 2q-ary-output channel with Markovian ergodic noise based on a finite queue. This channel can effectively model binary-modulated correlated Rayleigh fading channels with output quantization of resolution q. It is shown that the system can successfully exploit the channel's memory and soft-decision information. Signal-to-distortion gains of up to 2.3 dB are obtained for only 2 bits of soft-decision quantization over COVQ schemes designed for a hard-decision (q = 1) demodulated channel. Furthermore, gains as high as 4.6 dB can be achieved for a highly correlated channel, in comparison with systems designed for the ideally interleaved (memoryless) channel. Finally, the queue-based noise model is validated as an effective approximation of correlated fading channels by testing a COVQ trained using this model over the Rayleigh fading channel.
{"title":"Exploiting memory and soft-decision information in channel optimized quantization for correlated fading channels","authors":"Shervin Shahidi, F. Alajaji, T. Linder","doi":"10.1109/CWIT.2011.5872125","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872125","url":null,"abstract":"A channel optimized vector quantizer (COVQ) scheme is studied and evaluated for a recently introduced discrete binary-input 2q-ary-output channel with Markovian ergodic noise based on a finite queue. This channel can effectively model binary-modulated correlated Rayleigh fading channels with output quantization of resolution q. It is shown that the system can successfully exploit the channel's memory and soft-decision information. Signal-to-distortion gains of up to 2.3 dB are obtained for only 2 bits of soft-decision quantization over COVQ schemes designed for a hard-decision (q = 1) demodulated channel. Furthermore, gains as high as 4.6 dB can be achieved for a highly correlated channel, in comparison with systems designed for the ideally interleaved (memoryless) channel. Finally, the queue-based noise model is validated as an effective approximation of correlated fading channels by testing a COVQ trained using this model over the Rayleigh fading channel.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126471446","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872114
Morteza Varasteh, H. Behroozi
We study hybrid digital-analog (HDA) joint source-channel coding schemes in transmitting an analog Gaussian source over an AWGN channel in the presence of an interference, correlated with the source. We analyze these schemes to obtain achievable (mean-squared error) distortion-power tradeoffs. For comparison, we also obtain two outer bounds for the achievable distortion-power tradeoff; those are two necessary conditions under which (D,P) is achievable. Using numerical examples, we demonstrate that, a two-layered coding scheme consisting of analog and Costa coding performs well compared to other provided HDA schemes.
{"title":"On the transmission of a Gaussian source over an AWGN channel with correlated interference","authors":"Morteza Varasteh, H. Behroozi","doi":"10.1109/CWIT.2011.5872114","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872114","url":null,"abstract":"We study hybrid digital-analog (HDA) joint source-channel coding schemes in transmitting an analog Gaussian source over an AWGN channel in the presence of an interference, correlated with the source. We analyze these schemes to obtain achievable (mean-squared error) distortion-power tradeoffs. For comparison, we also obtain two outer bounds for the achievable distortion-power tradeoff; those are two necessary conditions under which (D,P) is achievable. Using numerical examples, we demonstrate that, a two-layered coding scheme consisting of analog and Costa coding performs well compared to other provided HDA schemes.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124757227","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 : 2011-05-17DOI: 10.1109/CWIT.2011.5872143
Victor Buttigieg
A maximum likelihood metric is derived for the decoding of variable-length codes over a Binary Substitution, Insertion and Deletion channel. Using this metric a near-maximum likelihood decoder is derived. It is shown that variable-length codes can be used effectively to correct for insertion, deletion and substitution errors.
{"title":"Using variable-length codes to correct Insertion, Deletion and substitution errors","authors":"Victor Buttigieg","doi":"10.1109/CWIT.2011.5872143","DOIUrl":"https://doi.org/10.1109/CWIT.2011.5872143","url":null,"abstract":"A maximum likelihood metric is derived for the decoding of variable-length codes over a Binary Substitution, Insertion and Deletion channel. Using this metric a near-maximum likelihood decoder is derived. It is shown that variable-length codes can be used effectively to correct for insertion, deletion and substitution errors.","PeriodicalId":250626,"journal":{"name":"2011 12th Canadian Workshop on Information Theory","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116755504","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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