Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990481
Dan Zhang, G. Ascheid
This paper presents a theoretical analysis for the coded bit error rate (BER) performance of the bit-interleaved coded modulation (BICM) transmission with two decoding schemes, i.e., BICM decoding and maximum likelihood sequence detection (MLSD). We especially focus on the influence of the codeword length on the BER. The simulation results demonstrate that such analytical results are accurate in the signal-to-noise ratio regimes of interest for general modulations and bits-tosymbol mappings (i.e., Gray and non-Gray mappings).
{"title":"BER analysis for BICM transmission over flat fading channels using finite length codewords","authors":"Dan Zhang, G. Ascheid","doi":"10.1109/SPAWC.2011.5990481","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990481","url":null,"abstract":"This paper presents a theoretical analysis for the coded bit error rate (BER) performance of the bit-interleaved coded modulation (BICM) transmission with two decoding schemes, i.e., BICM decoding and maximum likelihood sequence detection (MLSD). We especially focus on the influence of the codeword length on the BER. The simulation results demonstrate that such analytical results are accurate in the signal-to-noise ratio regimes of interest for general modulations and bits-tosymbol mappings (i.e., Gray and non-Gray mappings).","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130916536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990415
Jie Huang, Zhaohui Wang, Shengli Zhou, Zhengdao Wang
In this paper we consider a practical orthogonal frequency division multiplexing (OFDM) modulated and low-density parity-check (LDPC) channel coded two-way relay system employing physical-layer network coding (PLNC), where two terminals A and B desire to exchange information with each other with the help of a relay R which can be equipped with multiple receive antennas. Orthogonal frequency division multiplexing (OFDM) is adopted as the modulation scheme to resolve the synchronization problem in PLNC and doubly selective channels with intercarrier interference (ICI) are considered. The critical process in such a system is the calculation of the network-coded transmit codeword at the relay on basis of the superimposed channel-coded signals of the two terminals. Different from existing works on non-iterative receiver design, we here consider iterative receiver design. We propose two turbo equalization receivers, one is the conventional iterative separate detection and decoding (I-SDD), and the other one is based on a recently developed estimation scheme for PLNC. Gaussian message passing (GMP) and sum-product algorithm (SPA) are used for ICI-aware equalization and channel decoding respectively. We find through numerical simulations that the performance of the I-SDD receiver can catch up with that of the state-of-the-art PLNC-based receiver when more than one receive antennas are used. One promising feature about the ISDD receiver is that the channel decoding complexity is much lower than that of the PLNC-based receiver.
{"title":"Turbo equalization for OFDM modulated physical layer network coding","authors":"Jie Huang, Zhaohui Wang, Shengli Zhou, Zhengdao Wang","doi":"10.1109/SPAWC.2011.5990415","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990415","url":null,"abstract":"In this paper we consider a practical orthogonal frequency division multiplexing (OFDM) modulated and low-density parity-check (LDPC) channel coded two-way relay system employing physical-layer network coding (PLNC), where two terminals A and B desire to exchange information with each other with the help of a relay R which can be equipped with multiple receive antennas. Orthogonal frequency division multiplexing (OFDM) is adopted as the modulation scheme to resolve the synchronization problem in PLNC and doubly selective channels with intercarrier interference (ICI) are considered. The critical process in such a system is the calculation of the network-coded transmit codeword at the relay on basis of the superimposed channel-coded signals of the two terminals. Different from existing works on non-iterative receiver design, we here consider iterative receiver design. We propose two turbo equalization receivers, one is the conventional iterative separate detection and decoding (I-SDD), and the other one is based on a recently developed estimation scheme for PLNC. Gaussian message passing (GMP) and sum-product algorithm (SPA) are used for ICI-aware equalization and channel decoding respectively. We find through numerical simulations that the performance of the I-SDD receiver can catch up with that of the state-of-the-art PLNC-based receiver when more than one receive antennas are used. One promising feature about the ISDD receiver is that the channel decoding complexity is much lower than that of the PLNC-based receiver.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130947094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990483
N. Mahmood, F. Yilmaz, Mohamed-Slim Alouini
For meaningful co-existence of cognitive radios with primary system, it is imperative that the cognitive radio system is aware of how much interference it generates at the primary receivers. This can be done through statistical modeling of the interference as perceived at the primary receivers. In this work, we propose a generalized model for the interference generated by a cognitive radio network, in the presence of small and large scale fading, at a primary receiver located at the origin. We then demonstrate how this model can be used to estimate the impact of cognitive radio transmission on the primary receiver in terms of different outage probabilities. Finally, our analytical findings are validated through some selected computer-based simulations.
{"title":"A generalized and parameterized interference model for cognitive radio networks","authors":"N. Mahmood, F. Yilmaz, Mohamed-Slim Alouini","doi":"10.1109/SPAWC.2011.5990483","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990483","url":null,"abstract":"For meaningful co-existence of cognitive radios with primary system, it is imperative that the cognitive radio system is aware of how much interference it generates at the primary receivers. This can be done through statistical modeling of the interference as perceived at the primary receivers. In this work, we propose a generalized model for the interference generated by a cognitive radio network, in the presence of small and large scale fading, at a primary receiver located at the origin. We then demonstrate how this model can be used to estimate the impact of cognitive radio transmission on the primary receiver in terms of different outage probabilities. Finally, our analytical findings are validated through some selected computer-based simulations.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123105504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990408
P. Tarasak, Sumei Sun
We first address a sum-rate maximization problem under a sum-power constraint. By introducing the concept of virtual user, we solve the problem by using the Lagrange dual method. We then look into a sum-power minimization problem under sum-rate constraints. The Lagrange dual method and an exhaustive search method are proposed, which achieve similar performance, but the former has a lower complexity. Our simulation shows about 3-dB power saving of our scheme over an OFDMA system without network coding.
{"title":"Resource allocation for downlink two-user OFDMA systems with wireless network coding","authors":"P. Tarasak, Sumei Sun","doi":"10.1109/SPAWC.2011.5990408","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990408","url":null,"abstract":"We first address a sum-rate maximization problem under a sum-power constraint. By introducing the concept of virtual user, we solve the problem by using the Lagrange dual method. We then look into a sum-power minimization problem under sum-rate constraints. The Lagrange dual method and an exhaustive search method are proposed, which achieve similar performance, but the former has a lower complexity. Our simulation shows about 3-dB power saving of our scheme over an OFDMA system without network coding.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":" 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113950912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990409
Rohit Aggarwal, M. Assaad, C. E. Koksal, Philip Schniter
In this paper, we address the problem of joint scheduling and resource allocation in the downlink of an orthogonal frequency division multiple access (OFDMA)-based wireless network when the per-user SNR is known only in distribution. In particular, we consider sum-utility maximization over user schedules, powers, and code rates, subject to an instantaneous sum-power constraint. We consider both a “continuous” scenario where, during a time-slot, each OFDMA subchannel can be time-shared among multiple users and/or code rates, and a “discrete” scenario where no time-sharing is allowed. For the non-convex optimization problem arising in the continuous case, we propose an efficient exact solution. For the mixed-integer optimization problem arising in the discrete case, we propose a polynomial-complexity approximate solution and derive a bound on its optimality gap. We also provide a numerical study of goodput maximization for the SNR distribution that results from the use of pilot-aided MMSE channel estimation.
{"title":"Optimal resource allocation in OFDMA downlink systems with imperfect CSI","authors":"Rohit Aggarwal, M. Assaad, C. E. Koksal, Philip Schniter","doi":"10.1109/SPAWC.2011.5990409","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990409","url":null,"abstract":"In this paper, we address the problem of joint scheduling and resource allocation in the downlink of an orthogonal frequency division multiple access (OFDMA)-based wireless network when the per-user SNR is known only in distribution. In particular, we consider sum-utility maximization over user schedules, powers, and code rates, subject to an instantaneous sum-power constraint. We consider both a “continuous” scenario where, during a time-slot, each OFDMA subchannel can be time-shared among multiple users and/or code rates, and a “discrete” scenario where no time-sharing is allowed. For the non-convex optimization problem arising in the continuous case, we propose an efficient exact solution. For the mixed-integer optimization problem arising in the discrete case, we propose a polynomial-complexity approximate solution and derive a bound on its optimality gap. We also provide a numerical study of goodput maximization for the SNR distribution that results from the use of pilot-aided MMSE channel estimation.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121738341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990478
F. Harris, Xiaofei Chen, E. Venosa, F. Palmieri
Time-interleaved analog-to-digital converters (TI-ADCs) offer a significant increase in the available sample rate of ADCs. Their performance is degraded by timing and gain mismatches. Most of the literature on mismatch estimation and correction in TI-ADCs is concentrated on low-pass converting baseband signals. This paper provides a semi-blind solution, for both timing and gain mismatches correction, in the digital data section of a two-channel TI-ADC for band-pass input signals. This is a realistic communications system scenario. Modern system designs lean towards having the ADC interface with intermediate frequency (IF) signal in the analog section of a digital receiver rather than the DC centered, analog down converted, in-phase and quadrature pair.
{"title":"Two channel TI-ADC for communication signals","authors":"F. Harris, Xiaofei Chen, E. Venosa, F. Palmieri","doi":"10.1109/SPAWC.2011.5990478","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990478","url":null,"abstract":"Time-interleaved analog-to-digital converters (TI-ADCs) offer a significant increase in the available sample rate of ADCs. Their performance is degraded by timing and gain mismatches. Most of the literature on mismatch estimation and correction in TI-ADCs is concentrated on low-pass converting baseband signals. This paper provides a semi-blind solution, for both timing and gain mismatches correction, in the digital data section of a two-channel TI-ADC for band-pass input signals. This is a realistic communications system scenario. Modern system designs lean towards having the ADC interface with intermediate frequency (IF) signal in the analog section of a digital receiver rather than the DC centered, analog down converted, in-phase and quadrature pair.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133840292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990404
Y. Chau, K. Y. Huang
A new spatial diversity with sequential maximal ratio combining (S-MRC) is proposed and analyzed. In the S-MRC system, the diversity branches are added for combining one-by-one in a sequential manner, and a truncated sequential probability ratio test (TSPRT) is used for signal detection. By sequentially adding individual branches for combining, the power consumption from directly using all available branches can be saved. The S-MRC is more power-saving than the traditional MRC or the output-threshold MRC (OT-MRC). Numerical results for the bit error rate (BER) of the BPSK signaling over the independently and identically distributed (i.i.d.) Rayleigh fading channels are presented to illustrate the performance of the S-MRC which is much better than the OT-MRC and is identical to that of the traditional MRC if a suitable test threshold is used. Furthermore, the average number of active branches is much smaller than that of the traditional MRC.
{"title":"Spatial diversity with a new sequential maximal ratio combining over wireless fading channels","authors":"Y. Chau, K. Y. Huang","doi":"10.1109/SPAWC.2011.5990404","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990404","url":null,"abstract":"A new spatial diversity with sequential maximal ratio combining (S-MRC) is proposed and analyzed. In the S-MRC system, the diversity branches are added for combining one-by-one in a sequential manner, and a truncated sequential probability ratio test (TSPRT) is used for signal detection. By sequentially adding individual branches for combining, the power consumption from directly using all available branches can be saved. The S-MRC is more power-saving than the traditional MRC or the output-threshold MRC (OT-MRC). Numerical results for the bit error rate (BER) of the BPSK signaling over the independently and identically distributed (i.i.d.) Rayleigh fading channels are presented to illustrate the performance of the S-MRC which is much better than the OT-MRC and is identical to that of the traditional MRC if a suitable test threshold is used. Furthermore, the average number of active branches is much smaller than that of the traditional MRC.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116148335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990385
Yiyin Wang, G. Leus, Xiaoli Ma
In this paper, we propose a Kalman filter (KF) based tracking approach to track a target node with the assistance of anchors in an asynchronous network with clock offsets. We employ the asymmetric trip ranging (ATR) protocol to obtain TOA measurements and facilitate clock offset cancellation, and further derive a linear measurement model from the TOA measurements. Thus, the KF based on this linear measurement model does not have the modeling errors inherently contained in the Extended Kalman filter (EKF). Furthermore, low computational complexity makes the proposed KF a promising solution for practical use. We compare the proposed KF with the EKF. The simulation results corroborate its efficiency.
{"title":"Tracking a mobile node by asynchronous networks","authors":"Yiyin Wang, G. Leus, Xiaoli Ma","doi":"10.1109/SPAWC.2011.5990385","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990385","url":null,"abstract":"In this paper, we propose a Kalman filter (KF) based tracking approach to track a target node with the assistance of anchors in an asynchronous network with clock offsets. We employ the asymmetric trip ranging (ATR) protocol to obtain TOA measurements and facilitate clock offset cancellation, and further derive a linear measurement model from the TOA measurements. Thus, the KF based on this linear measurement model does not have the modeling errors inherently contained in the Extended Kalman filter (EKF). Furthermore, low computational complexity makes the proposed KF a promising solution for practical use. We compare the proposed KF with the EKF. The simulation results corroborate its efficiency.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115419034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990452
S. Firouzabadi, A. Goldsmith
We investigate the optimal placement of transmit antennas in distributed antenna systems. Our optimization framework imposes no constraints on the location of the antennas. Based on stochastic approximation theory, we adopt a formulation that is suitable for node placement optimization in various wireless network scenarios. We show that optimal placement of antennas inside the coverage region can significantly improve the power efficiency of wireless networks. We obtain the optimal placement topologies for different numbers of antennas and illustrate that the circular deployment is not optimum in general. Finally, we show via simulations that the optimal placement solution does not depend on the underlying shadowing model.
{"title":"Optimal placement of distributed antennas in cellular systems","authors":"S. Firouzabadi, A. Goldsmith","doi":"10.1109/SPAWC.2011.5990452","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990452","url":null,"abstract":"We investigate the optimal placement of transmit antennas in distributed antenna systems. Our optimization framework imposes no constraints on the location of the antennas. Based on stochastic approximation theory, we adopt a formulation that is suitable for node placement optimization in various wireless network scenarios. We show that optimal placement of antennas inside the coverage region can significantly improve the power efficiency of wireless networks. We obtain the optimal placement topologies for different numbers of antennas and illustrate that the circular deployment is not optimum in general. Finally, we show via simulations that the optimal placement solution does not depend on the underlying shadowing model.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123485814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-06-26DOI: 10.1109/SPAWC.2011.5990455
Ya-Feng Liu, Yu-Hong Dai, Z. Luo
For a general MIMO interference channel, we can determine the feasibility of linear interference alignment via minimizing the leakage interference. This paper gives a complete complexity characterization of the leakage interference minimization problem. It is shown that, when each transmitter (receiver) is equipped with at least three antennas and each receiver (transmitter) is equipped with at least two antennas, the problem of checking whether the interference in the network can be perfectly aligned is strongly NP-hard. Moreover, when each transmit/receive node is equipped with two or more antennas, leakage interference minimization can not be solved (even approximately) in polynomial time, unless P = NP.
{"title":"On the complexity of leakage interference minimization for interference alignment","authors":"Ya-Feng Liu, Yu-Hong Dai, Z. Luo","doi":"10.1109/SPAWC.2011.5990455","DOIUrl":"https://doi.org/10.1109/SPAWC.2011.5990455","url":null,"abstract":"For a general MIMO interference channel, we can determine the feasibility of linear interference alignment via minimizing the leakage interference. This paper gives a complete complexity characterization of the leakage interference minimization problem. It is shown that, when each transmitter (receiver) is equipped with at least three antennas and each receiver (transmitter) is equipped with at least two antennas, the problem of checking whether the interference in the network can be perfectly aligned is strongly NP-hard. Moreover, when each transmit/receive node is equipped with two or more antennas, leakage interference minimization can not be solved (even approximately) in polynomial time, unless P = NP.","PeriodicalId":102244,"journal":{"name":"2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123673431","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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