Pub Date : 2011-11-01DOI: 10.1109/ISWCS.2011.6125381
J. Ramis, G. Femenias, L. Carrasco
State-of-the-art wireless communications standards combine (hybrid) automatic repeat request (HARQ) protocols at the data link control (DLC) layer with adaptive modulation and coding (AMC) strategies at the physical layer. Most previous work on cross-layer modeling of these networks assumes the availability of ideal channel state information (CSI). However, in practical systems the CSI used to perform link adaptation may be outdated. This paper presents a generalized cross-layer multidimensional discrete-time Markov chain (DTMC)-based queuing model that jointly exploits the capabilities of ARQ and AMC, by explicitly accounting for imperfections in the AMC scheme caused by the delay in the CSI feedback channel. Based on the stationary state probability distribution of the proposed multidimensional DTMC, closed-form analytical expressions for performance metrics such as average throughput, queue length, packet delay and packet loss rate are derived, and an analysis of the impact of using outdated CSI on these performance parameters is presented.
{"title":"Cross-layer modeling of AMC/ARQ-based wireless networks with outdated CSI","authors":"J. Ramis, G. Femenias, L. Carrasco","doi":"10.1109/ISWCS.2011.6125381","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125381","url":null,"abstract":"State-of-the-art wireless communications standards combine (hybrid) automatic repeat request (HARQ) protocols at the data link control (DLC) layer with adaptive modulation and coding (AMC) strategies at the physical layer. Most previous work on cross-layer modeling of these networks assumes the availability of ideal channel state information (CSI). However, in practical systems the CSI used to perform link adaptation may be outdated. This paper presents a generalized cross-layer multidimensional discrete-time Markov chain (DTMC)-based queuing model that jointly exploits the capabilities of ARQ and AMC, by explicitly accounting for imperfections in the AMC scheme caused by the delay in the CSI feedback channel. Based on the stationary state probability distribution of the proposed multidimensional DTMC, closed-form analytical expressions for performance metrics such as average throughput, queue length, packet delay and packet loss rate are derived, and an analysis of the impact of using outdated CSI on these performance parameters is presented.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128013262","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125345
Iqbal Shahid, P. Yahampath
In this paper, we present a distributed joint source-channel (DJSC) coding approach for a pair of correlated binary sources transmitted over independent binary symmetric channels. This problem is of interest in wireless sensor network applications, where encoders with low complexity and delay may be required. In the proposed method, a judiciously chosen fraction of information bits and a fraction of parity bits obtained by puncturing the output of a systematic channel code are transmitted for each source. We obtain the achievable rate region for the proposed coding scheme and show that it coincides with the Slepian-Wolf lower bound as the channel error probability approaches zero. Experimental results obtained with a practical implementation based on LDPC codes are also presented which demonstrate that for short coding block lengths (or low delay coding), the proposed DJSC coding method outperforms separate distributed source coding and channel coding.
{"title":"Distributed joint source-channel coding of correlated binary sources in wireless sensor networks","authors":"Iqbal Shahid, P. Yahampath","doi":"10.1109/ISWCS.2011.6125345","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125345","url":null,"abstract":"In this paper, we present a distributed joint source-channel (DJSC) coding approach for a pair of correlated binary sources transmitted over independent binary symmetric channels. This problem is of interest in wireless sensor network applications, where encoders with low complexity and delay may be required. In the proposed method, a judiciously chosen fraction of information bits and a fraction of parity bits obtained by puncturing the output of a systematic channel code are transmitted for each source. We obtain the achievable rate region for the proposed coding scheme and show that it coincides with the Slepian-Wolf lower bound as the channel error probability approaches zero. Experimental results obtained with a practical implementation based on LDPC codes are also presented which demonstrate that for short coding block lengths (or low delay coding), the proposed DJSC coding method outperforms separate distributed source coding and channel coding.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128088721","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125275
M. N. Khormuji, M. Skoglund
A class of semi-deterministic relay channels is introduced and it is shown that for channels in the class capacity can be achieved using an instantaneous relaying scheme. Applications to Gaussian channels are then discussed.
{"title":"Capacity achieving instantaneous relaying","authors":"M. N. Khormuji, M. Skoglund","doi":"10.1109/ISWCS.2011.6125275","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125275","url":null,"abstract":"A class of semi-deterministic relay channels is introduced and it is shown that for channels in the class capacity can be achieved using an instantaneous relaying scheme. Applications to Gaussian channels are then discussed.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124437259","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125451
G. Papa, D. Ciuonzo, G. Romano, P. Rossi
This paper presents a Soft-Input Soft-Output (SISO) version of the King Decoder (KD) algorithm, i.e. a tree-search based optimum detection algorithm with contained computational complexity for Multiple-Input Multiple-Output (MIMO) communication systems. More specifically, four versions of the KD are considered and compared with Max-Log detection. The effectiveness of the algorithm is tested within a system employing bit-interleaved coded modulation, and both one-shot and iterative receivers are considered. Simulation results for the performance are presented in terms of Bit Error Rate (BER) vs Signal-to-Noise Ratio (SNR), showing excellent results.
{"title":"Soft-Input Soft-Output King Decoder for coded MIMO wireless communications","authors":"G. Papa, D. Ciuonzo, G. Romano, P. Rossi","doi":"10.1109/ISWCS.2011.6125451","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125451","url":null,"abstract":"This paper presents a Soft-Input Soft-Output (SISO) version of the King Decoder (KD) algorithm, i.e. a tree-search based optimum detection algorithm with contained computational complexity for Multiple-Input Multiple-Output (MIMO) communication systems. More specifically, four versions of the KD are considered and compared with Max-Log detection. The effectiveness of the algorithm is tested within a system employing bit-interleaved coded modulation, and both one-shot and iterative receivers are considered. Simulation results for the performance are presented in terms of Bit Error Rate (BER) vs Signal-to-Noise Ratio (SNR), showing excellent results.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132508564","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125298
L. Polak, T. Kratochvil
This paper deals with the latest digital TV standards DVB-SH and DVB-T2 with focus on utilization of the new DVB-T2 system for the next generation of mobile TV broadcasting. The work is especially focused on performance of new types of forward error coding and usage of new mobile modes in classical OFDM modulation for digital TV broadcasting. Evaluation of the transmission distortions in portable and mobile TV environment and analysis of performance in various fading channels are the main novelties contained in this paper. Dependences of BER on C/N ratio for all types of payload modulation are compared with focus on mobile TV services availability. Applications for simulation of the transmission were developed in MATLAB. Finally, the achieved results are evaluated and discussed with promising expectations from DVB-T2 in mobile environment.
{"title":"DVB-SH-A and DVB-T2 performance in mobile TV environment","authors":"L. Polak, T. Kratochvil","doi":"10.1109/ISWCS.2011.6125298","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125298","url":null,"abstract":"This paper deals with the latest digital TV standards DVB-SH and DVB-T2 with focus on utilization of the new DVB-T2 system for the next generation of mobile TV broadcasting. The work is especially focused on performance of new types of forward error coding and usage of new mobile modes in classical OFDM modulation for digital TV broadcasting. Evaluation of the transmission distortions in portable and mobile TV environment and analysis of performance in various fading channels are the main novelties contained in this paper. Dependences of BER on C/N ratio for all types of payload modulation are compared with focus on mobile TV services availability. Applications for simulation of the transmission were developed in MATLAB. Finally, the achieved results are evaluated and discussed with promising expectations from DVB-T2 in mobile environment.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132231418","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125306
Jingjing Liu, R. D. Lamare
We propose two innovative extension schemes for Rate-Compatible (RC) Low-Density Parity-Check (LDPC) codes with short/moderate block lengths. The proposed designs are based on the counting cycles algorithm and the Approximate Cycle Extrinsic Message Degree (EMD). Our layer-structured extension schemes enjoy a linear-time encodable ability and relatively low decoding complexity thanks to low degree profiles with limited decoding iterations, such that they intrinsically fit in a type-II hybrid automatic repeat-request (ARQ) system. Simulation results show that the proposed approaches manage to yield a performance gain of up to 0.3 dB when compared to the existing extension technique.
{"title":"Finite-length rate-compatible LDPC codes based on extension techniques","authors":"Jingjing Liu, R. D. Lamare","doi":"10.1109/ISWCS.2011.6125306","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125306","url":null,"abstract":"We propose two innovative extension schemes for Rate-Compatible (RC) Low-Density Parity-Check (LDPC) codes with short/moderate block lengths. The proposed designs are based on the counting cycles algorithm and the Approximate Cycle Extrinsic Message Degree (EMD). Our layer-structured extension schemes enjoy a linear-time encodable ability and relatively low decoding complexity thanks to low degree profiles with limited decoding iterations, such that they intrinsically fit in a type-II hybrid automatic repeat-request (ARQ) system. Simulation results show that the proposed approaches manage to yield a performance gain of up to 0.3 dB when compared to the existing extension technique.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133032834","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125400
Moritz Beermann, Tobias Breddermann, P. Vary
Much attention has been paid to Low-Density Parity-Check (LDPC) codes since their rediscovery by MacKay. They belong to the most powerful channel coding techniques known today and have a broad range of applications. In wireless communication systems it is desirable to be able to adjust the code rate of the employed channel coding scheme (rate-matching) to allow for a flexible strength of error protection for different services and to be able to adapt to the varying quality of the wireless transmission channel. Many of the current systems that employ LDPC codes like, e.g., WiMAX or WLAN specify separate codes for each supported code rate. This paper, in contrast, addresses the problem of using only one mother code and matching (almost) arbitrary code rates that are lower than the mother code rate by inserting known (dummy) bits into the information bit sequence before encoding (also known as pruning or code shortening). We present a novel rule of determining (heuristically) optimized positions of dummy bits within the information bit sequence suitable for LDPC codes. Simulation results show that the frame error rate performance can be improved by the novel approach of dummy bit insertion especially in the error floor region.
{"title":"Rate-compatible LDPC codes using optimized dummy bit insertion","authors":"Moritz Beermann, Tobias Breddermann, P. Vary","doi":"10.1109/ISWCS.2011.6125400","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125400","url":null,"abstract":"Much attention has been paid to Low-Density Parity-Check (LDPC) codes since their rediscovery by MacKay. They belong to the most powerful channel coding techniques known today and have a broad range of applications. In wireless communication systems it is desirable to be able to adjust the code rate of the employed channel coding scheme (rate-matching) to allow for a flexible strength of error protection for different services and to be able to adapt to the varying quality of the wireless transmission channel. Many of the current systems that employ LDPC codes like, e.g., WiMAX or WLAN specify separate codes for each supported code rate. This paper, in contrast, addresses the problem of using only one mother code and matching (almost) arbitrary code rates that are lower than the mother code rate by inserting known (dummy) bits into the information bit sequence before encoding (also known as pruning or code shortening). We present a novel rule of determining (heuristically) optimized positions of dummy bits within the information bit sequence suitable for LDPC codes. Simulation results show that the frame error rate performance can be improved by the novel approach of dummy bit insertion especially in the error floor region.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133635153","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125427
A. Rao, Mohamed-Slim Alouini
In this paper, we analyze the performance of adaptive modulation with single-cell multiuser scheduling over independent but not identical distributed (i.n.i.d.) Nakagami fading channels. Closed-form expressions are derived for the average channel capacity, spectral efficiency, and bit-error-rate (BER) for both constant-power variable-rate and variable-power variable-rate uncoded M-ary quadrature amplitude modulation (M-QAM) schemes. We also study the impact of time delay on the average BER of adaptive M-QAM. Selected numerical results show that the multiuser diversity brings a considerably better performance even over i.n.i.d. fading environments.
{"title":"Adaptive modulation with best user selection over non-identical Nakagami fading channels","authors":"A. Rao, Mohamed-Slim Alouini","doi":"10.1109/ISWCS.2011.6125427","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125427","url":null,"abstract":"In this paper, we analyze the performance of adaptive modulation with single-cell multiuser scheduling over independent but not identical distributed (i.n.i.d.) Nakagami fading channels. Closed-form expressions are derived for the average channel capacity, spectral efficiency, and bit-error-rate (BER) for both constant-power variable-rate and variable-power variable-rate uncoded M-ary quadrature amplitude modulation (M-QAM) schemes. We also study the impact of time delay on the average BER of adaptive M-QAM. Selected numerical results show that the multiuser diversity brings a considerably better performance even over i.n.i.d. fading environments.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117245575","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125311
Georgios I. Papadakis, N. Pronios
In this paper, we analyze and evaluate throughput performance of open-loop and closed-loop MIMO slotted ALOHA ad hoc networks with multiple receivers. We employ two slotted ALOHA variants with realistic modelling considerations; interaction(s) between the link and the MAC-layer are explicitly accounted for via a probabilistic approach using the output SINR of the receiver's MIMO processing stage. We employ a general framework for MAC-layer performance evaluation and use the two slotted ALOHA variants to determine network throughput and to provide various trade-off analyses and numerical examples.
{"title":"Throughput performance of certain MIMO-based ad-hoc networks","authors":"Georgios I. Papadakis, N. Pronios","doi":"10.1109/ISWCS.2011.6125311","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125311","url":null,"abstract":"In this paper, we analyze and evaluate throughput performance of open-loop and closed-loop MIMO slotted ALOHA ad hoc networks with multiple receivers. We employ two slotted ALOHA variants with realistic modelling considerations; interaction(s) between the link and the MAC-layer are explicitly accounted for via a probabilistic approach using the output SINR of the receiver's MIMO processing stage. We employ a general framework for MAC-layer performance evaluation and use the two slotted ALOHA variants to determine network throughput and to provide various trade-off analyses and numerical examples.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":" 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120941609","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 : 2011-11-01DOI: 10.1109/ISWCS.2011.6125417
T. Murakami, R. Kudo, Y. Asai, T. Kumagai, M. Mizoguchi
Inter-cell interference (ICI) from nearby cells can substantially degrade the sum-rate in WLAN systems. To improve the sum-rate in actual WLAN systems, some papers have investigated distributed multi-cell beamforming to mitigate ICI by zero forcing beamforming. All most of these approaches consider single-user multiple input multiple output (SU-MIMO) systems. In this paper, we present three techniques for distributed multi-cell beamforming for multi-user MIMO (MU-MIMO) systems with the same total number of transmit and receive antennas. The first technique is distributed multi-cell beamforming using receiver selection. The second one is antenna selection at the receiver. The last one is an iterative technique in which transmitter weight is updated at the transmitter to correspond to receiver weight. The sum-rate of these techniques with imperfect channel state information at transmitter (CSIT) is evaluated. We clarify the effectiveness of these techniques for MU-MIMO systems.
{"title":"Performance evaluation of distributed multi-cell beamforming for MU-MIMO systems","authors":"T. Murakami, R. Kudo, Y. Asai, T. Kumagai, M. Mizoguchi","doi":"10.1109/ISWCS.2011.6125417","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125417","url":null,"abstract":"Inter-cell interference (ICI) from nearby cells can substantially degrade the sum-rate in WLAN systems. To improve the sum-rate in actual WLAN systems, some papers have investigated distributed multi-cell beamforming to mitigate ICI by zero forcing beamforming. All most of these approaches consider single-user multiple input multiple output (SU-MIMO) systems. In this paper, we present three techniques for distributed multi-cell beamforming for multi-user MIMO (MU-MIMO) systems with the same total number of transmit and receive antennas. The first technique is distributed multi-cell beamforming using receiver selection. The second one is antenna selection at the receiver. The last one is an iterative technique in which transmitter weight is updated at the transmitter to correspond to receiver weight. The sum-rate of these techniques with imperfect channel state information at transmitter (CSIT) is evaluated. We clarify the effectiveness of these techniques for MU-MIMO systems.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116273376","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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