Pub Date : 2012-04-03DOI: 10.1109/NCC.2012.6176842
P. Reddy, V. P. T. Ijyas, S. Sameer
This paper deals with the maximum-likelihood (ML) estimation of carrier frequency offsets (CFO) in OFDMA uplink transmissions. A pilot preamble-based approach is proposed that makes use of the conjugate direction search algorithm. In many earlier works, the multidimensional optimization involved in this joint estimation problem is broken into a series of one-dimensional searches. All these methods calculate the frequency offsets of the different users one after the other. However in this work, the Powell's method of Conjugate Direction Search is made use of, which gives all estimates simultaneously regardless of the number of active users in the system. Its performance is compared with a computationally-efficient approximation of the Alternating Projection algorithm [8]. The method compares favourably in this regard and has the added advantage of flexibilty of application to any subcarrier assignment scheme in OFDMA systems. The performance advantages of this new method are substantiated through simulation studies.
{"title":"A conjugate direction search algorithm for ML estimation of frequency offsets in OFDMA uplink","authors":"P. Reddy, V. P. T. Ijyas, S. Sameer","doi":"10.1109/NCC.2012.6176842","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176842","url":null,"abstract":"This paper deals with the maximum-likelihood (ML) estimation of carrier frequency offsets (CFO) in OFDMA uplink transmissions. A pilot preamble-based approach is proposed that makes use of the conjugate direction search algorithm. In many earlier works, the multidimensional optimization involved in this joint estimation problem is broken into a series of one-dimensional searches. All these methods calculate the frequency offsets of the different users one after the other. However in this work, the Powell's method of Conjugate Direction Search is made use of, which gives all estimates simultaneously regardless of the number of active users in the system. Its performance is compared with a computationally-efficient approximation of the Alternating Projection algorithm [8]. The method compares favourably in this regard and has the added advantage of flexibilty of application to any subcarrier assignment scheme in OFDMA systems. The performance advantages of this new method are substantiated through simulation studies.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127518263","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176762
A. Anamika, V. Priye
Closed form formulae are derived to study crosstalk degradation due to cross-phase modulation (XPM) induced crosstalk in periodically amplified and dispersion compensated fiber links. The formulae are used to evaluate the crosstalk performance of different modulation formats especially differential phase-shift keying (DPSK) and ON?OFF keying (OOK) which are widely used in optical communication. Crosstalk sensitivity for different data rates and pulse shapes prevalent in optical data transmission is also evaluated. The study shows that minimum XPM induced crosstalk can be achieved for 40 Gb/s RZ-DPSK signal with 33.3% duty cycle in WDM system.
{"title":"XPM induced crosstalk in dispersion compensated fiber links for DPSK and OOK modulation format","authors":"A. Anamika, V. Priye","doi":"10.1109/NCC.2012.6176762","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176762","url":null,"abstract":"Closed form formulae are derived to study crosstalk degradation due to cross-phase modulation (XPM) induced crosstalk in periodically amplified and dispersion compensated fiber links. The formulae are used to evaluate the crosstalk performance of different modulation formats especially differential phase-shift keying (DPSK) and ON?OFF keying (OOK) which are widely used in optical communication. Crosstalk sensitivity for different data rates and pulse shapes prevalent in optical data transmission is also evaluated. The study shows that minimum XPM induced crosstalk can be achieved for 40 Gb/s RZ-DPSK signal with 33.3% duty cycle in WDM system.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116841931","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176779
P. Ghosh, S. Das, S. Naravaram, P. Chandhar
Green Radio has emerged as one of the most important considerations in the present scenario of global warming. It is known that the power consumption of a Base Station is not only due to the radio power transmitted and the power consumed by the digital signal processing transceiver units but also due to the huge amount of power consumed by the cooling system and power backup units. It has been seen that although traffic load varies over a large range during a 24 hour cycle the power consumption does not vary proportionally. Traffic load dependent power saving is one of the foci of this work. An important aspect included in this work is the huge penetration loss that is added to the system Signal to Interference plus Noise Ratio (SINR) during night time when most of the users are considered to be indoor. This work focuses on the performance evaluation cell sleep mode to save power (reduce carbon foot print). Results relating to three sector urban micro-cell scenario as per International Telecommunication Union (ITU) specification are presented. Traffic load threshold for activating the sleep mode is also identified.
{"title":"Energy saving in OFDMA cellular systems using base-station sleep mode: 3GPP-LTE a case study","authors":"P. Ghosh, S. Das, S. Naravaram, P. Chandhar","doi":"10.1109/NCC.2012.6176779","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176779","url":null,"abstract":"Green Radio has emerged as one of the most important considerations in the present scenario of global warming. It is known that the power consumption of a Base Station is not only due to the radio power transmitted and the power consumed by the digital signal processing transceiver units but also due to the huge amount of power consumed by the cooling system and power backup units. It has been seen that although traffic load varies over a large range during a 24 hour cycle the power consumption does not vary proportionally. Traffic load dependent power saving is one of the foci of this work. An important aspect included in this work is the huge penetration loss that is added to the system Signal to Interference plus Noise Ratio (SINR) during night time when most of the users are considered to be indoor. This work focuses on the performance evaluation cell sleep mode to save power (reduce carbon foot print). Results relating to three sector urban micro-cell scenario as per International Telecommunication Union (ITU) specification are presented. Traffic load threshold for activating the sleep mode is also identified.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128388004","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176778
S. Sahay, D. Pande, V. Gadre, P. Sohani
The various techniques available for Chirp Parameter Estimation (CPE) can be categorized as Transform-based approaches, filter-bank approaches and statistical estimation based approaches. CPE involves estimation of time versus instantaneous frequency relationship and estimation of amplitude-variation of chirp-envelope with time. This paper introduces a new approach for estimating the parameters of an incoming noisy chirp signal by passing it through a collection of filters of known responses. Instantaneous frequency of the noisy chirp is then `collectively' estimated from the responses of these known filters to the chirp. The main advantage of the proposed approach is that, no a-priori information regarding the time versus instantaneous frequency relationship is required. Moreover, the technique works equally well for various types of modulations in the chirp. Results are encouraging even when amplitude of chirp-envelope is time-varying.
{"title":"Model-independent approach for Chirp Parameter Estimation employing collection of filters","authors":"S. Sahay, D. Pande, V. Gadre, P. Sohani","doi":"10.1109/NCC.2012.6176778","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176778","url":null,"abstract":"The various techniques available for Chirp Parameter Estimation (CPE) can be categorized as Transform-based approaches, filter-bank approaches and statistical estimation based approaches. CPE involves estimation of time versus instantaneous frequency relationship and estimation of amplitude-variation of chirp-envelope with time. This paper introduces a new approach for estimating the parameters of an incoming noisy chirp signal by passing it through a collection of filters of known responses. Instantaneous frequency of the noisy chirp is then `collectively' estimated from the responses of these known filters to the chirp. The main advantage of the proposed approach is that, no a-priori information regarding the time versus instantaneous frequency relationship is required. Moreover, the technique works equally well for various types of modulations in the chirp. Results are encouraging even when amplitude of chirp-envelope is time-varying.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128449260","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176743
V. U. Sankar, V. Sharma
Femtocells are a new concept which improves the coverage and capacity of a cellular system. We consider the problem of channel allocation and power control to different users within a Femtocell. Knowing the channels available, the channel states and the rate requirements of different users the Femtocell base station (FBS), allocates the channels to different users to satisfy their requirements. Also, the Femtocell should use minimal power so as to cause least interference to its neighboring Femtocells and outside users. We develop efficient, low complexity algorithms which can be used online by the Femtocell. The users may want to transmit data or voice. We compare our algorithms with the optimal solutions.
{"title":"Subchannel Allocation and Power Control in Femtocells to Provide Quality of Service","authors":"V. U. Sankar, V. Sharma","doi":"10.1109/NCC.2012.6176743","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176743","url":null,"abstract":"Femtocells are a new concept which improves the coverage and capacity of a cellular system. We consider the problem of channel allocation and power control to different users within a Femtocell. Knowing the channels available, the channel states and the rate requirements of different users the Femtocell base station (FBS), allocates the channels to different users to satisfy their requirements. Also, the Femtocell should use minimal power so as to cause least interference to its neighboring Femtocells and outside users. We develop efficient, low complexity algorithms which can be used online by the Femtocell. The users may want to transmit data or voice. We compare our algorithms with the optimal solutions.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128647157","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176744
M. Bansal, A. Trivedi
Multiple-Input Multiple-Output (MIMO) technology has great potential for improving the throughput of Wireless mesh networks (WMNs). In this paper, we investigate joint rate allocation, routing, and stream control scheduling problem in MIMO-based WMNs, where multiple antennas are exploited to increase the capacity via interference suppression (IS) and/or spatial multiplexing (SM). The notion of transmission configuration (TC) is considered and a heuristic algorithm is proposed to find a good subset of all possible TCs. Using these TCs, we present convex programming (CP) formulations to find a proportional fair rate allocation solution. The simulation results demonstrate that performance of the proposed heuristic algorithm is very near to the optimal solution. The computational complexity of the proposed heuristic algorithm is substantially less compared to the optimal solution.
{"title":"Fair rate allocation, routing, and stream control scheduling in MIMO-based WMNs","authors":"M. Bansal, A. Trivedi","doi":"10.1109/NCC.2012.6176744","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176744","url":null,"abstract":"Multiple-Input Multiple-Output (MIMO) technology has great potential for improving the throughput of Wireless mesh networks (WMNs). In this paper, we investigate joint rate allocation, routing, and stream control scheduling problem in MIMO-based WMNs, where multiple antennas are exploited to increase the capacity via interference suppression (IS) and/or spatial multiplexing (SM). The notion of transmission configuration (TC) is considered and a heuristic algorithm is proposed to find a good subset of all possible TCs. Using these TCs, we present convex programming (CP) formulations to find a proportional fair rate allocation solution. The simulation results demonstrate that performance of the proposed heuristic algorithm is very near to the optimal solution. The computational complexity of the proposed heuristic algorithm is substantially less compared to the optimal solution.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129265409","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176794
M. Yargholi, A. P. Tarighat, M. Maghsoodi
In this paper a CMOS low noise amplifier is designed for radio ultra-wide band receivers. The design process includes; input matching network, cascoded structure, RC feedback loop, RL load and output matching network. The LNA is implemented in TSMC RF CMOS 0.18μm technology with minimum noise figure of 2.3dB, maximum gain (S21) of 15.1dB with gain flatness of 0.7, S22<;-15dB and IIP3 of - 10dBm at 3-5 GHZ bandwidth. The power dissipation is 11.4 mW while using 1.5V voltage supply.
{"title":"Resistive feedback LNA for radio ultra-wideband receivers","authors":"M. Yargholi, A. P. Tarighat, M. Maghsoodi","doi":"10.1109/NCC.2012.6176794","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176794","url":null,"abstract":"In this paper a CMOS low noise amplifier is designed for radio ultra-wide band receivers. The design process includes; input matching network, cascoded structure, RC feedback loop, RL load and output matching network. The LNA is implemented in TSMC RF CMOS 0.18μm technology with minimum noise figure of 2.3dB, maximum gain (S21) of 15.1dB with gain flatness of 0.7, S22<;-15dB and IIP3 of - 10dBm at 3-5 GHZ bandwidth. The power dissipation is 11.4 mW while using 1.5V voltage supply.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"1949 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129120531","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176806
Aman Jaiswal, A. Jagannatham
Wireless Sensor Networks (WSNs) have gained rapid popularity due to their deployment for critical applications such as defense, health care, agriculture, weather and tsunami monitoring etc. However, such sensor networks are fundamentally constrained by the data errors arising due to the harsh power constrained sensing environment. In this paper, we propose a novel multi-sensor vector prediction history tree (V-PHT) decision algorithm for error correction in a wireless sensor network (WSN). This scheme is based on the recently proposed prediction history tree (PHT) algorithm for model based error correction in WSNs. However, unlike the existing PHT model, which exclusively exploits the temporal correlation inherent in the narrowband sensor data, the proposed V-PHT model for sensor data correction exploits the joint spatial and temporal correlation in sensor data arising out of geographical proximity of the sensor nodes. Towards this end, an optimal multi-sensor spatio-temporal AR model is developed for predictive modeling of the sensor data. Further, employing the spatio-temporal correlation structure amongst the sensors, we develop a robust framework for optimal estimation of the multi-sensor AR predictor model. Simulation results obtained employing sensor data models available in literature demonstrate that the proposed spatio-temporal V-PHT model for error correction in a WSN results in a significant reduction in mean-squared error (MSE) compared to the existing PHT scheme which exploits only temporal correlation.
{"title":"Multi-sensor spatio-temporal vector prediction history tree (V-PHT) model for error correction in Wireless Sensor Networks","authors":"Aman Jaiswal, A. Jagannatham","doi":"10.1109/NCC.2012.6176806","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176806","url":null,"abstract":"Wireless Sensor Networks (WSNs) have gained rapid popularity due to their deployment for critical applications such as defense, health care, agriculture, weather and tsunami monitoring etc. However, such sensor networks are fundamentally constrained by the data errors arising due to the harsh power constrained sensing environment. In this paper, we propose a novel multi-sensor vector prediction history tree (V-PHT) decision algorithm for error correction in a wireless sensor network (WSN). This scheme is based on the recently proposed prediction history tree (PHT) algorithm for model based error correction in WSNs. However, unlike the existing PHT model, which exclusively exploits the temporal correlation inherent in the narrowband sensor data, the proposed V-PHT model for sensor data correction exploits the joint spatial and temporal correlation in sensor data arising out of geographical proximity of the sensor nodes. Towards this end, an optimal multi-sensor spatio-temporal AR model is developed for predictive modeling of the sensor data. Further, employing the spatio-temporal correlation structure amongst the sensors, we develop a robust framework for optimal estimation of the multi-sensor AR predictor model. Simulation results obtained employing sensor data models available in literature demonstrate that the proposed spatio-temporal V-PHT model for error correction in a WSN results in a significant reduction in mean-squared error (MSE) compared to the existing PHT scheme which exploits only temporal correlation.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124223764","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176850
Sathish Babu Sekar, S. Sengupta, K. Bandyopadhyay
The exponential growth in the global navigation satellite system (GNSS) initiated the way for modernization of GPS and the other GNSS including numerous signal structure innovations to ensure better performance measures over legacy GNSS systems. The adoption of the secondary short codes is one of these to accomplish data symbol synchronization, spectral separation and narrowband interference protection. In this paper, we study the generation and searching methods of secondary short codes based on the optimization of their relative performance measures. The merits of the generated codes have been compared with the standard existing codes using the same performance measures.
{"title":"Analysis of secondary short codes for satellite navigation","authors":"Sathish Babu Sekar, S. Sengupta, K. Bandyopadhyay","doi":"10.1109/NCC.2012.6176850","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176850","url":null,"abstract":"The exponential growth in the global navigation satellite system (GNSS) initiated the way for modernization of GPS and the other GNSS including numerous signal structure innovations to ensure better performance measures over legacy GNSS systems. The adoption of the secondary short codes is one of these to accomplish data symbol synchronization, spectral separation and narrowband interference protection. In this paper, we study the generation and searching methods of secondary short codes based on the optimization of their relative performance measures. The merits of the generated codes have been compared with the standard existing codes using the same performance measures.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127624710","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 : 2012-04-03DOI: 10.1109/NCC.2012.6176774
K. Deka, A. Rajesh, P. Bora
This paper presents a new scheme to reduce the detrimental effect of the trapping sets in the regular and irregular low density parity check (LDPC) codes. By adding only one new check node and properly selecting its edges, the performance in the error floor region can be improved. Simulation results show that the proposed scheme decreases the bit error rate (BER) and frame error rate (FER) significantly in the high signal-to-noise ratio (SNR) region at the expense of negligible rate loss.
{"title":"Additional check node to improve the performance of LDPC codes in the error floor region","authors":"K. Deka, A. Rajesh, P. Bora","doi":"10.1109/NCC.2012.6176774","DOIUrl":"https://doi.org/10.1109/NCC.2012.6176774","url":null,"abstract":"This paper presents a new scheme to reduce the detrimental effect of the trapping sets in the regular and irregular low density parity check (LDPC) codes. By adding only one new check node and properly selecting its edges, the performance in the error floor region can be improved. Simulation results show that the proposed scheme decreases the bit error rate (BER) and frame error rate (FER) significantly in the high signal-to-noise ratio (SNR) region at the expense of negligible rate loss.","PeriodicalId":178278,"journal":{"name":"2012 National Conference on Communications (NCC)","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128169764","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：