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.2011.6125275
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.2011.6125400
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.2011.6125321
S. Tarnoi, W. Kumwilaisak, P. Saengudomlert
This paper proposes a QoS-aware routing protocol in lossy wireless networks to support heterogeneous layered unicast transmissions and to improve energy usage through cooperative network coding (CNC). The proposed protocol consists of two steps. The first step uses an optimization framework to compute routes of all layered unicast flows. The constraints of this optimization problem are based on the Quality-of-Service (QoS) guarantee, the transmission rate of each data layer, and interference effects in wireless transmissions. The second step decides whether or not CNC will be applied to different unicast flows at intermediate nodes. The decision criterions are based on the network structure and the QoS guarantee. In particular, if CNC at any intermediate node does not result in violating the QoS requirements of the involved unicast flows, CNC will be applied. Else, different unicast flows will be separately transmitted to destinations without CNC. Numerical results from different network topologies and QoS requirements show that the proposed routing protocol gives better throughput and energy efficiency while providing the QoS guarantees to multiple unicast flows compared to existing unicast transmission schemes.
{"title":"QoS-aware routing protocol for heterogeneous wireless unicasts with cooperative network coding","authors":"S. Tarnoi, W. Kumwilaisak, P. Saengudomlert","doi":"10.1109/ISWCS.2011.6125321","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125321","url":null,"abstract":"This paper proposes a QoS-aware routing protocol in lossy wireless networks to support heterogeneous layered unicast transmissions and to improve energy usage through cooperative network coding (CNC). The proposed protocol consists of two steps. The first step uses an optimization framework to compute routes of all layered unicast flows. The constraints of this optimization problem are based on the Quality-of-Service (QoS) guarantee, the transmission rate of each data layer, and interference effects in wireless transmissions. The second step decides whether or not CNC will be applied to different unicast flows at intermediate nodes. The decision criterions are based on the network structure and the QoS guarantee. In particular, if CNC at any intermediate node does not result in violating the QoS requirements of the involved unicast flows, CNC will be applied. Else, different unicast flows will be separately transmitted to destinations without CNC. Numerical results from different network topologies and QoS requirements show that the proposed routing protocol gives better throughput and energy efficiency while providing the QoS guarantees to multiple unicast flows compared to existing unicast transmission schemes.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"50 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":"130989358","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.2011.6125310
Khodr A. Saaifan, W. Henkel
In this paper, we consider the detection problem of binary signals corrupted by Class-A interference for two observations per symbol. The Class-A density contains infinitely many terms of scaled Gaussian-mixture densities, which yields an optimum detector that requires a high computational complexity. The linear (Gaussian) detector can be used, but it suffers from a significant performance degradation in stong impulse environments. The main objective of this paper is to design a simple detector with optimum performance. We start from the optimum decision boundaries, where we propose a piecewise linear approximation for nonlinear regions. As a result, we introduce a novel piecewise detector, which has much less complexity compared with the optimum one. Simulation results show a near-optimal performance for the proposed detectors in different impulse channel environments. Moreover, we show that one and two piecewise linear approximation per each nonlinear region is sufficient to approach the optimum performance.
{"title":"A linear piecewise suboptimum detector for signals in class-A noise","authors":"Khodr A. Saaifan, W. Henkel","doi":"10.1109/ISWCS.2011.6125310","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125310","url":null,"abstract":"In this paper, we consider the detection problem of binary signals corrupted by Class-A interference for two observations per symbol. The Class-A density contains infinitely many terms of scaled Gaussian-mixture densities, which yields an optimum detector that requires a high computational complexity. The linear (Gaussian) detector can be used, but it suffers from a significant performance degradation in stong impulse environments. The main objective of this paper is to design a simple detector with optimum performance. We start from the optimum decision boundaries, where we propose a piecewise linear approximation for nonlinear regions. As a result, we introduce a novel piecewise detector, which has much less complexity compared with the optimum one. Simulation results show a near-optimal performance for the proposed detectors in different impulse channel environments. Moreover, we show that one and two piecewise linear approximation per each nonlinear region is sufficient to approach the optimum performance.","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":"128379457","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.2011.6125308
Da Lio, F. Rossetto, L. Vangelista
Accurate channel estimation may require complex algorithms for effective results, especially in the case of a multiuser detector. The introduction of Graphic Processing Units (GPUs) has opened up new possibilities for the implementation of numerically intensive channel estimation algorithms. This paper studies the implementation on GPUs of channel estimation algorithms for channels affected by strong phase noise. While classic Maximum Likelihood estimation is still the most competitive in terms of throughput and memory bandwidth, Steepest Ascent algorithms show the largest speed improvement due to their structure, which is the most suitable for implementation on a parallel processor like the GPU.
{"title":"Design considerations for massively parallel channel estimation algorithms","authors":"Da Lio, F. Rossetto, L. Vangelista","doi":"10.1109/ISWCS.2011.6125308","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125308","url":null,"abstract":"Accurate channel estimation may require complex algorithms for effective results, especially in the case of a multiuser detector. The introduction of Graphic Processing Units (GPUs) has opened up new possibilities for the implementation of numerically intensive channel estimation algorithms. This paper studies the implementation on GPUs of channel estimation algorithms for channels affected by strong phase noise. While classic Maximum Likelihood estimation is still the most competitive in terms of throughput and memory bandwidth, Steepest Ascent algorithms show the largest speed improvement due to their structure, which is the most suitable for implementation on a parallel processor like the GPU.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"14 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":"115335847","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.2011.6125304
Mahesh Gupta Vutukuri, R. Malladi, K. Kuchi, R. D. Koilpillai
Voice services over Adaptive Multiuser channel in One Slot (VAMOS) performance in the presence of GMSK interferer is presented. Widely-Linear (WL) MMSE filtering is used to cancel the co-channel GMSK interferer while performing α-QPSK detection. In this paper, two ways of estimating the Sub Channel Power Imbalance Ratio (SCPIR) are discussed. Due to the colouration of the resultant impairment after filtering, WL metric is proposed which incorporates error covariance between I/Q components in the metric computation. WL RSSE is used as the equalizer. Simulation results using the proposed receiver architecture show significant performance important over conventional VAMOS receivers.
{"title":"SAIC receiver algorithms for VAMOS downlink transmission","authors":"Mahesh Gupta Vutukuri, R. Malladi, K. Kuchi, R. D. Koilpillai","doi":"10.1109/ISWCS.2011.6125304","DOIUrl":"https://doi.org/10.1109/ISWCS.2011.6125304","url":null,"abstract":"Voice services over Adaptive Multiuser channel in One Slot (VAMOS) performance in the presence of GMSK interferer is presented. Widely-Linear (WL) MMSE filtering is used to cancel the co-channel GMSK interferer while performing α-QPSK detection. In this paper, two ways of estimating the Sub Channel Power Imbalance Ratio (SCPIR) are discussed. Due to the colouration of the resultant impairment after filtering, WL metric is proposed which incorporates error covariance between I/Q components in the metric computation. WL RSSE is used as the equalizer. Simulation results using the proposed receiver architecture show significant performance important over conventional VAMOS receivers.","PeriodicalId":414065,"journal":{"name":"2011 8th International Symposium on Wireless Communication Systems","volume":"122 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":"115512626","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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