Pub Date : 2013-03-28DOI: 10.1109/NCC.2013.6487932
M. Mukherjee, Preetam Kumar
As multimedia applications gain significant importance in 4G communication, there is a need to design communication system to transmit different data rates with required QoS. Traditional spread multiple access system uses WH code that results in higher multiple access interference (MAI) due to loss in orthogonality over multipath channel. In this work, phase characteristics of carrier interferometry (CI) codes and spreading diversity of WH code are used to provide multiple data rate schemes for spread CI multicarrier code division multiple access (spread CI/MC-CDMA) system. Bit error rate (BER) performance is evaluated for under-load and full-load variable rate spread CI/MC-CDMA system over correlated multipath fading channel at different system loads. The effect of phase jitters due to local oscillator imperfection on multiple rate communication has been analyzed and verified through simulations.
{"title":"Multirate schemes for WH-spread-CI/MC-CDMA over corelated frequency selective channel","authors":"M. Mukherjee, Preetam Kumar","doi":"10.1109/NCC.2013.6487932","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487932","url":null,"abstract":"As multimedia applications gain significant importance in 4G communication, there is a need to design communication system to transmit different data rates with required QoS. Traditional spread multiple access system uses WH code that results in higher multiple access interference (MAI) due to loss in orthogonality over multipath channel. In this work, phase characteristics of carrier interferometry (CI) codes and spreading diversity of WH code are used to provide multiple data rate schemes for spread CI multicarrier code division multiple access (spread CI/MC-CDMA) system. Bit error rate (BER) performance is evaluated for under-load and full-load variable rate spread CI/MC-CDMA system over correlated multipath fading channel at different system loads. The effect of phase jitters due to local oscillator imperfection on multiple rate communication has been analyzed and verified through simulations.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"45 18","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132974076","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 : 2013-03-28DOI: 10.1109/NCC.2013.6487963
B. Dhivagar, K. Kuchi, K. Giridhar
Single carrier frequency division multiple access (SC-FDMA) based systems such as long term evolution (LTE) uplink experience severe inter symbol interference (ISI) in highly frequency selective channels. The conventional linear receivers such as the linear minimum mean square error(LMMSE) based receiver fail to address this issue, thereby degrading the performance of the system. This paper proposes a new iterative multiple input multiple output decision feedback equalizer (MIMO-DFE) which does not require the estimation of any parameters for canceling ISI. It also derives a closed form expression for the residual noise covariance after equalization which is used for maximum likelihood detection (MLD) across streams. Simulations show that the proposed receiver yields significant performance gains especially in the high signal-to-noise-ratio (SNR) regime with only a modest increase in computational complexity.
{"title":"An iterative MIMO-DFE receiver with MLD for uplink SC-FDMA","authors":"B. Dhivagar, K. Kuchi, K. Giridhar","doi":"10.1109/NCC.2013.6487963","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487963","url":null,"abstract":"Single carrier frequency division multiple access (SC-FDMA) based systems such as long term evolution (LTE) uplink experience severe inter symbol interference (ISI) in highly frequency selective channels. The conventional linear receivers such as the linear minimum mean square error(LMMSE) based receiver fail to address this issue, thereby degrading the performance of the system. This paper proposes a new iterative multiple input multiple output decision feedback equalizer (MIMO-DFE) which does not require the estimation of any parameters for canceling ISI. It also derives a closed form expression for the residual noise covariance after equalization which is used for maximum likelihood detection (MLD) across streams. Simulations show that the proposed receiver yields significant performance gains especially in the high signal-to-noise-ratio (SNR) regime with only a modest increase in computational complexity.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122343039","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 : 2013-03-28DOI: 10.1109/NCC.2013.6487901
S. Yadav, P. K. Upadhyay
In this paper, we investigate the performance of two-way amplify-and-forward (AF) relaying scheme over independent but not necessarily identically distributed (i.n.i.d.) cascaded generalized-K fading channels. We derive expressions for both upper and lower bounds on overall outage probability (OOP) for the considered two-way AF relaying system. Further, we derive tight closed-form approximate expressions for the OOP as well as for the average symbol error probability (ASEP) for the considered relaying system. We present simulation and numerical results to validate the proposed theoretical analysis, and to demonstrate the effects of various channel parameters on the overall system performance. Our results reveal that the overall system performance improves with increase in shadowing and/or fading parameters, as well as with decrease in number of cascading channels over two hops.
{"title":"Performance analysis of two-way AF relaying systems over cascaded generalized-K fading channels","authors":"S. Yadav, P. K. Upadhyay","doi":"10.1109/NCC.2013.6487901","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487901","url":null,"abstract":"In this paper, we investigate the performance of two-way amplify-and-forward (AF) relaying scheme over independent but not necessarily identically distributed (i.n.i.d.) cascaded generalized-K fading channels. We derive expressions for both upper and lower bounds on overall outage probability (OOP) for the considered two-way AF relaying system. Further, we derive tight closed-form approximate expressions for the OOP as well as for the average symbol error probability (ASEP) for the considered relaying system. We present simulation and numerical results to validate the proposed theoretical analysis, and to demonstrate the effects of various channel parameters on the overall system performance. Our results reveal that the overall system performance improves with increase in shadowing and/or fading parameters, as well as with decrease in number of cascading channels over two hops.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116708193","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 : 2013-03-28DOI: 10.1109/NCC.2013.6487989
Santosh K. Waddi, P. C. Pandey, Nitya Tiwari
A spectral subtraction technique is presented for real-time speech enhancement in the aids used by hearing impaired listeners. For reducing computational complexity and memory requirement, it uses a cascaded-median based estimation of the noise spectrum without voice activity detection. The technique is implemented and tested for satisfactory real-time operation, with sampling frequency of 12 kHz, processing using window length of 30 ms with 50% overlap, and noise estimation by 3-frame 4-stage cascaded-median, on a 16-bit fixed-point DSP processor with on-chip FFT hardware. Enhancement of speech with different types of additive stationary and non-stationary noise resulted in SNR advantage of 4 – 13 dB.
{"title":"Speech enhancement using spectral subtraction and cascaded-median based noise estimation for hearing impaired listeners","authors":"Santosh K. Waddi, P. C. Pandey, Nitya Tiwari","doi":"10.1109/NCC.2013.6487989","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487989","url":null,"abstract":"A spectral subtraction technique is presented for real-time speech enhancement in the aids used by hearing impaired listeners. For reducing computational complexity and memory requirement, it uses a cascaded-median based estimation of the noise spectrum without voice activity detection. The technique is implemented and tested for satisfactory real-time operation, with sampling frequency of 12 kHz, processing using window length of 30 ms with 50% overlap, and noise estimation by 3-frame 4-stage cascaded-median, on a 16-bit fixed-point DSP processor with on-chip FFT hardware. Enhancement of speech with different types of additive stationary and non-stationary noise resulted in SNR advantage of 4 – 13 dB.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117313022","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 : 2013-03-28DOI: 10.1109/NCC.2013.6487905
Arjun Kumar, Ashwini Sawant, M. Kartikeyan
This paper consists of the design studies of fractal DGS microwave filter. Minkowski fractal structure is inserted in different section of a dumbbell shaped DGS and their responses are compared on the basis of roll-off factor, effective capacitance and effective inductance. Then on the basis of this study a low pass filter having cutoff frequency of 5.4 GHz is designed using FFF configuration of Minkowski fractal DGS and its comparison with low pass filter implemented by dumbbell shaped DGS having same substrate area is carried out.
{"title":"Investigation of fractal DGS microwave filters","authors":"Arjun Kumar, Ashwini Sawant, M. Kartikeyan","doi":"10.1109/NCC.2013.6487905","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487905","url":null,"abstract":"This paper consists of the design studies of fractal DGS microwave filter. Minkowski fractal structure is inserted in different section of a dumbbell shaped DGS and their responses are compared on the basis of roll-off factor, effective capacitance and effective inductance. Then on the basis of this study a low pass filter having cutoff frequency of 5.4 GHz is designed using FFF configuration of Minkowski fractal DGS and its comparison with low pass filter implemented by dumbbell shaped DGS having same substrate area is carried out.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"313 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114131140","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 : 2013-03-28DOI: 10.1109/NCC.2013.6487923
C. Kundu, R. Bose
In this paper an alternate numerical approach to evaluate average symbol error probability (ASEP) in log-normal fading channel is proposed. Accuracy of the proposed method is compared with that of existing methods. ASEP of maximal ratio combining (MRC) Rake receiver in Ultrawide band (UWB) multipath channel is evaluated with the help of proposed numerical approach taking a new quadrature based approximate log-normal “power sum” distribution. ASEP of the same is compared with that of obtained using other approximate distributions of log-normal “power sum”. It is shown that the proposed method is more general than other methods over both the log-normal and log-normal “power sum” distributed (UWB) channel with comparable accuracy.
{"title":"An alternate method for calculating average probability of error in log-normal channel for UWB","authors":"C. Kundu, R. Bose","doi":"10.1109/NCC.2013.6487923","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487923","url":null,"abstract":"In this paper an alternate numerical approach to evaluate average symbol error probability (ASEP) in log-normal fading channel is proposed. Accuracy of the proposed method is compared with that of existing methods. ASEP of maximal ratio combining (MRC) Rake receiver in Ultrawide band (UWB) multipath channel is evaluated with the help of proposed numerical approach taking a new quadrature based approximate log-normal “power sum” distribution. ASEP of the same is compared with that of obtained using other approximate distributions of log-normal “power sum”. It is shown that the proposed method is more general than other methods over both the log-normal and log-normal “power sum” distributed (UWB) channel with comparable accuracy.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"284 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116170564","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 : 2013-03-28DOI: 10.1109/NCC.2013.6487912
S. N. Pradhan, R. Devarajan, S. C. Jha, V. Bhargava
With the increasing number of small cell nodes, the power consumption in Heterogeneous Networks (HetNets) has increased significantly resulting in problems such as higher interference among nodes, higher outage, and decreased capacity. In this paper, we propose various power allocation schemes where we allocate power among the heterogeneous user equipments. First, we propose a scheme which jointly minimizes outage probability and total power consumption in the network. Second, we devise a scheme which jointly maximizes total throughput and minimizes total power consumption. These schemes formulate multi-objective optimization problems, which are then solved using weighted sum approach. Third, we investigate a scheme to maximize energy efficiency defined as system throughput achieved per unit power consumption. Simulation results clarify the need for tradeoff among various performance parameters in practice based on device's remaining battery capacity, system outage target and quality of service (QoS) requirement in terms of signal-to-interference-plus-noise ratio (SINR). The results also show that the proposed power allocation schemes are highly efficient in attaining such tradeoffs.
{"title":"Uplink power allocation schemes for heterogeneous cellular networks","authors":"S. N. Pradhan, R. Devarajan, S. C. Jha, V. Bhargava","doi":"10.1109/NCC.2013.6487912","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487912","url":null,"abstract":"With the increasing number of small cell nodes, the power consumption in Heterogeneous Networks (HetNets) has increased significantly resulting in problems such as higher interference among nodes, higher outage, and decreased capacity. In this paper, we propose various power allocation schemes where we allocate power among the heterogeneous user equipments. First, we propose a scheme which jointly minimizes outage probability and total power consumption in the network. Second, we devise a scheme which jointly maximizes total throughput and minimizes total power consumption. These schemes formulate multi-objective optimization problems, which are then solved using weighted sum approach. Third, we investigate a scheme to maximize energy efficiency defined as system throughput achieved per unit power consumption. Simulation results clarify the need for tradeoff among various performance parameters in practice based on device's remaining battery capacity, system outage target and quality of service (QoS) requirement in terms of signal-to-interference-plus-noise ratio (SINR). The results also show that the proposed power allocation schemes are highly efficient in attaining such tradeoffs.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121016464","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 : 2013-03-28DOI: 10.1109/NCC.2013.6487902
Cibile K. Kanjirathumkal, S. Sameer, L. Jacob
In this paper, exact expressions are derived for the moments and performance metrics for a compound channel in multi-hop transmissions with transparent relays over independent and not necessarily identically distributed Weibull fading channels. Firstly, various moments are derived using characteristic function of second kind, based on Mellin transform. Using these moments, two useful statistical performance metrics named coefficient of variation and amount of fade are also derived for the end to end system. Moments and the metrics derived are in tractable compact forms and can be easily extended to other distributions also. These results can be directly applied in the study of outage probability and average bit error probability of such multi-hop transmissions. The proposed mathematical analysis is complimented by various numerical results, demonstrating the impact of the proposed expressions
{"title":"On the computation of exact moments and performance metrics for multihop transparent weibull relay channels","authors":"Cibile K. Kanjirathumkal, S. Sameer, L. Jacob","doi":"10.1109/NCC.2013.6487902","DOIUrl":"https://doi.org/10.1109/NCC.2013.6487902","url":null,"abstract":"In this paper, exact expressions are derived for the moments and performance metrics for a compound channel in multi-hop transmissions with transparent relays over independent and not necessarily identically distributed Weibull fading channels. Firstly, various moments are derived using characteristic function of second kind, based on Mellin transform. Using these moments, two useful statistical performance metrics named coefficient of variation and amount of fade are also derived for the end to end system. Moments and the metrics derived are in tractable compact forms and can be easily extended to other distributions also. These results can be directly applied in the study of outage probability and average bit error probability of such multi-hop transmissions. The proposed mathematical analysis is complimented by various numerical results, demonstrating the impact of the proposed expressions","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122217960","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 : 2013-03-28DOI: 10.1109/NCC.2013.6488031
R. Kodali, Kashyapkumar H. Patel, N. Sarma
Wireless Sensor Networks (WSN's) are resource constrained networks, demanding energy efficient cryptographic algorithms in order to extend security to them. When compared with the popular RSA algorithm, Elliptic Curve Cryptography (ECC) offers similar level of security with smaller key size requirements. An efficient implementation of ECC heavily relies on the scalar multiplication operation. An efficient method for the elliptic curve point multiplication operation is proposed and its resource requirements are compared with binary and non-adjacent form (NAF) techniques. While comparing these, addition and doubling operations are considered. The proposed scalar multiplication technique makes use of both affine and projective coordinate systems while carrying out addition and doubling operations. The number of computations required to perform these operations is compared and an appropriate coordinate system is chosen for each of the operations.
{"title":"Energy efficient elliptic curve point multiplication for WSN applications","authors":"R. Kodali, Kashyapkumar H. Patel, N. Sarma","doi":"10.1109/NCC.2013.6488031","DOIUrl":"https://doi.org/10.1109/NCC.2013.6488031","url":null,"abstract":"Wireless Sensor Networks (WSN's) are resource constrained networks, demanding energy efficient cryptographic algorithms in order to extend security to them. When compared with the popular RSA algorithm, Elliptic Curve Cryptography (ECC) offers similar level of security with smaller key size requirements. An efficient implementation of ECC heavily relies on the scalar multiplication operation. An efficient method for the elliptic curve point multiplication operation is proposed and its resource requirements are compared with binary and non-adjacent form (NAF) techniques. While comparing these, addition and doubling operations are considered. The proposed scalar multiplication technique makes use of both affine and projective coordinate systems while carrying out addition and doubling operations. The number of computations required to perform these operations is compared and an appropriate coordinate system is chosen for each of the operations.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131328294","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 : 2013-03-28DOI: 10.1109/NCC.2013.6488012
Deshmukh Aniket Anand, S. Jana
Chronological ordering of Sanskrit texts engaged numerous researchers over centuries. Early subjective efforts, based on historical tradition, astronomical references, and comparative linguistics, graduated to statistical techniques; however, intimate knowledge of the language was still required. In this backdrop, we propose an information-theoretic measure, namely the entropy rate, as a chronological indicator, and buttress our thesis with experimental evidence. The proposed measure, requiring minimal linguistic knowledge, could be attractive for its simplicity, and its basis in rigorous theoretical foundations. In particular, we establish prediction by the partial matching (PPM) algorithm as an efficient entropy estimation technique for Sanskrit texts, and showed that the resultant estimate indicates the chronology of landmark texts starting from the Rigveda, to Kalidasa's works, to Rupa Goswami's Padyavali.
{"title":"Chronology of Sanskrit texts: An information-theoretic corroboration","authors":"Deshmukh Aniket Anand, S. Jana","doi":"10.1109/NCC.2013.6488012","DOIUrl":"https://doi.org/10.1109/NCC.2013.6488012","url":null,"abstract":"Chronological ordering of Sanskrit texts engaged numerous researchers over centuries. Early subjective efforts, based on historical tradition, astronomical references, and comparative linguistics, graduated to statistical techniques; however, intimate knowledge of the language was still required. In this backdrop, we propose an information-theoretic measure, namely the entropy rate, as a chronological indicator, and buttress our thesis with experimental evidence. The proposed measure, requiring minimal linguistic knowledge, could be attractive for its simplicity, and its basis in rigorous theoretical foundations. In particular, we establish prediction by the partial matching (PPM) algorithm as an efficient entropy estimation technique for Sanskrit texts, and showed that the resultant estimate indicates the chronology of landmark texts starting from the Rigveda, to Kalidasa's works, to Rupa Goswami's Padyavali.","PeriodicalId":202526,"journal":{"name":"2013 National Conference on Communications (NCC)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128304772","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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