{"title":"LSTM-Deep Neural Networks based Predistortion Linearizer for High Power Amplifiers","authors":"Deepmala Phartiyal, M. Rawat","doi":"10.1109/NCC.2019.8732178","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732178","url":null,"abstract":"Linear high power amplifiers (HPAs) are the need of current communications technology. But, almost all PAs show non-linear characteristics during amplification which are reflected in the transmitted signal in the form of distortions. Linearization is a process to suppress the effect of the nonlinear characteristic of a PA. Various methods are available to perform linearization. Predistortion (PD) linearization methods are very successful due to its simplicity in design and ease of integration with PAs. PD linearization methods observe the PA dynamic characteristics (nonlinearity) and then formulate an “inverse transfer function” to suppress this non-linearity. In the last decade, machine learning (ML) based PD linearizers are proposed and proved useful. Since then, numerous ML-PD linearizers have been developed. Shallow neural networks (NNs) based PD linearizers are successfully used to map the inverse transfer function but lack generalization performance in the presence of system conditions (IQ imbalance, DC offset). With deep learning (DL) technology, deep neural networks (DNNs) can map the complex inverse transfer function under different system conditions. This study proposes a long short-term memory (LSTM) DNN based PD linearizer for linearization of PA under different conditions. In this study, it is shown that LSTM is able to extract and exploit memory effects of PA over the perceptron. Comparative results with shallow NNs suggest reliable potential in the proposed DNN model in terms of generalization performance.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"421 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76735969","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}
{"title":"Splitting Merged Characters of Kannada Benchmark Dataset using Simplified Paired-Valleys and L-Cut","authors":"H. Kumar, A. Madhavaraj, A. Ramakrishnan","doi":"10.1109/NCC.2019.8732239","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732239","url":null,"abstract":"We reduce the computational complexity of the paired-valley algorithm for splitting merged characters, from Θ(N2) down to Θ(N), where $N$ is the number of symbols merged. We also propose an effective way (L-cut algorithm) to separate the merged half-consonants (known in Kannada as ottus) from the base symbols. We have created a benchmark dataset of 4033 sub-word images in Kannada, each comprising two or more merged characters. We test the recognition accuracy of Tesseract OCR on the created benchmark dataset, before and after applying our technique. The accuracy of Tesseract v3 OCR on the created dataset of 61.6% increases by 20% to a value of 81.7% after the splitting of the characters by our method. The algorithm's scalability to other scripts has been explored by limited experiments on Telugu and Tamil.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"29 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85012273","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}
{"title":"Slot Cut Modified Triangular Shape Microstrip Antenna for Circular Polarization","authors":"Akshay Doshi, A. Deshmukh, S. Deshmukh, K. P. Ray","doi":"10.1109/NCC.2019.8732180","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732180","url":null,"abstract":"Modified design of triangular microstrip antenna obtained by combining two triangular shape patches is discussed. The offset distance between two patches tunes the spacing between orthogonal mode frequencies of the patch which yields circular polarized response with axial ratio bandwidth of 5%. Further to realize compact configuration, slot cut design of offset triangular overlap patches is studied. The rectangular slot helps in tuning the spacing between offset triangular patches along with offset distance to yield circular polarization. The detailed parametric study for the effects of slot along with offset distance in circular polarized antenna is presented. The tuning of orthogonal frequencies is obtained at lower offset distance between two patches for slot cut antenna. The optimum axial ratio bandwidth of 70 MHz in 1500 MHz frequency band is obtained along with broadside gain of 7 dBi and VSWR Bandwidth of 747 MHz. In optimum case slot cut overlapped design offers 42% reduction in patch area.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"40 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79091748","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}
{"title":"Predistortion Linearizer Design for Ku Band RF Power Amplifier","authors":"Girish Chandra Tripathi, M. Rawat","doi":"10.1109/NCC.2019.8732215","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732215","url":null,"abstract":"This paper presents a $K_{u}$ band analog predistorter linearizer for improving the linearity of high-power radio frequency (RF) amplifiers. This method is applicable for both solid-state power amplifiers (SSPA) and traveling-wave tube amplifiers (TWTA). The designed linearizer consists of analog components, hence it is wideband as compared to the digital predistortion. Moreover, due to most of the passive components, the circuit is simpler and with the advantage of individual control of amplitude modulation to amplitude modulation (AM-AM) and amplitude modulation to phase modulation (AM-PM) conversions. For proof of concept, the designed linearizer is simulated with ZX60- $pmb{14012}mathbf{L}+mathbf{ class}$ AB SSPA. The S2D SSPA model is extracted using vector network analyzer. The proposed linearizer shows a reduction in third order intermodulation of 37 dB approximately at 4 dB output power backoff for two-tone signal. Similarly, for Long-Term Evolution (LTE) 20 MHz signal after linearization adjacent channel power ratio is approximately 47 dBc and shows a correction of 16 dB.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"21 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73981682","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}
A. Deka, Priyankoo Sarmah, K. Samudravijaya, S. Prasanna
{"title":"Development of Assamese Text-to-speech System using Deep Neural Network","authors":"A. Deka, Priyankoo Sarmah, K. Samudravijaya, S. Prasanna","doi":"10.1109/NCC.2019.8732262","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732262","url":null,"abstract":"This paper describes the development of a text-to-speech system for Assamese language, using Deep Neural Network (DNN). The system is trained with speech data, collected by a consortium, that is available free of cost for academic use. The DNN based method eliminates the need for a grapheme to phoneme conversion; rather, it synthesizes speech directly from the UTF-8 based Assamese script. The results of objective and subjective evaluations confirm that the Assamese speech synthesized using DNN approach is better than the ones synthesized using the traditional hidden Markov model based text-to-speech system.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"181 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74869800","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}
{"title":"Towards the Exact Rate Memory Tradeoff in Coded Caching","authors":"K. Vijith, B. K. Rai, T. Jacob","doi":"10.1109/NCC.2019.8732186","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732186","url":null,"abstract":"Caching plays an important role in improving internet performance by keeping a fraction of the files closer to the end user. The peak data traffic in the network can be significantly reduced by proper utilization of caching. Recent studies have shown that coded caching does help in further reducing the data traffic over uncoded caching. In this paper, we consider the problem of the exact rate memory tradeoff in coded caching. For the (3, 3) canonical cache network, a new caching scheme to achieve the memory rate pair (5/3,1/2) is introduced. This scheme is further extended to the (4, 4) canonical cache network, to achieve the memory rate pair (11/4,1/3). We prove the optimality of both the proposed schemes by deriving new lower bounds and thus partially characterizing the exact rate memory tradeoff in coded caching.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"55 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91279972","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}
{"title":"Brain Tumor Segmentation Using Discriminator Loss","authors":"Joydeep Das, Rashmin Patel, Vinod Pankajakshan","doi":"10.1109/NCC.2019.8732196","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732196","url":null,"abstract":"The emerging field of Computer Vision has found enormous applications in our day-to-day lives and Medical Image Processing is one of the most prominent fields among them. Brain Tumor Segmentation is an important and challenging task because of the variety in shapes, sizes and texture content of the various types of brain tumors. Specifically, MICCAI BraTS organizes Brain Tumor Segmentation challenge every year. Since the evolution of CNNs it has obtained state-of-the-art results in the majority of computer vision related tasks. On BraTS Challenge 2017, an assemble average of various CNN models (EMMA) holds the state-of-the-art performance. In this paper, we have proposed a model inspired by the classic Generative Adversarial Network (GAN). The proposed network has two models namely, Generator or Segmentor which generates label map of the input image and a Discriminator which helps the Generator model for an optimum solution by taking into account both short as well as long-distance spatial correlations between pixels with the help of a novel multi-scale loss function. The proposed architecture has three GANs in a cascaded fashion, each for Whole Tumor, Tumor Core and Enhancing Tumor, where the former network helps in effective reduction of false positives for the later networks. Our method also employs a multi-scale loss function derived from intermediate layers of Discriminator rather than depending just on a final layer cross-entropy loss. A mutli-scale loss function also reduces unnecessary smoothing on contours. The proposed method performed comparatively better than the state-of-the-art techniques, having Dice scores of 0.820, 0.874 and 0.783 for Enhancing Tumor, Whole Tumor and Tumor Core respectively.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"12 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74277603","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}
Rakesh Mundlamuri, B. Thangapandian, Vijay Kumar Chakka, Srikanth Goli
{"title":"A Graph Based Clustering and Preconditioning of V-MIMO Wireless Sensor Networks","authors":"Rakesh Mundlamuri, B. Thangapandian, Vijay Kumar Chakka, Srikanth Goli","doi":"10.1109/NCC.2019.8732213","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732213","url":null,"abstract":"This paper presents a graph based methodology for increasing the channel capacity of Virtual-Multiple Input Multiple Output (V-MIMO) defined over a Wireless Sensor Network (WSN). A fully connected graph $mathcal{G}(mathcal{V}, mathcal{E}, mathcal{W})$ is defined for a WSN. Then, we propose a new clustering algorithm based on the Fiedler vector of the graph $mathcal{G}$ which divides the sensor nodes $mathcal{V}$ into twoclusters (transmitting and receiving antennas). The links between these two clusters results in V-MIMO network. Next, a Modified Maximum Spanning Tree Search algorithm (MMASTS) is proposed on V-MIMO to enhance the average channel capacity. Simulation performance of average channel capacity and uncoded Bit Error Rate (BER) are plotted using different precoding techniques like Zero Forcing (ZF) and Minimum Mean Square Error (MMSE). These are also used for comparing the performance of proposed Fiedler vector based clustering with $k$- means clustering.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"19 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82720647","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}
{"title":"Maximally Recoverable Codes with Hierarchical Locality","authors":"Aaditya M. Nair, Lalitha Vadlamani","doi":"10.1109/NCC.2019.8732208","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732208","url":null,"abstract":"Maximally recoverable codes are a class of codes which recover from all potentially recoverable erasure patterns given the locality constraints of the code. In earlier works, these codes have been studied in the context of codes with locality. The notion of locality has been extended to hierarchical locality, which allows for locality to gradually increase in levels with the increase in the number of erasures. We consider the locality constraints imposed by codes with two-level hierarchical locality and define maximally recoverable codes with data-local and local hierarchical locality. We derive certain properties related to their punctured codes and minimum distance. We give a procedure to construct hierarchical data-local MRCs from hierarchical local MRCs. We provide a construction of hierarchical local MRCs for all parameters. For the case of one global parity, we provide a different construction of hierarchical local MRC over a lower field size.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"29 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2019-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72858605","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}
Mehul Anghan, Rashmi Kamran, Nihir Gulati, N. Nambath, Shalabh Gupta
{"title":"Adaptive Polarization Control for Coherent Optical Links with Polarization Multiplexed Carrier","authors":"Mehul Anghan, Rashmi Kamran, Nihir Gulati, N. Nambath, Shalabh Gupta","doi":"10.1109/NCC.2019.8732190","DOIUrl":"https://doi.org/10.1109/NCC.2019.8732190","url":null,"abstract":"Self-homodyne systems with polarization multiplexed carrier offer an local oscillator-less (LO-less) coherent receiver with simplified signal processing requirement that can be a good candidate for high-speed short-reach data center interconnects. The practical implementation of these systems is limited by the requirement of polarization control at the receiver end for separating the carrier and the modulated signal. In this paper, effect of polarization impairments in polarization diversity based systems is studied and modeled. A novel and practical adaptive polarization control technique based on optical power feedback from one polarization is proposed for polarization multiplexed carrier based systems and verified through simulation results. The application of the proposed concept is also experimentally demonstrated for a quadrature phase shift keying (QPSK) system with polarization multiplexed carrier.","PeriodicalId":6870,"journal":{"name":"2019 National Conference on Communications (NCC)","volume":"16 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81239498","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}