Over the past decade, the physical (PHY) layer of communication systems has evolved with the addition of techniques such as orthogonal frequency division multiplexing (OFDM) and multi-carrier aggregation. This has resulted in significant performance improvements, but it has come at the cost of increased power consumption and system complexity. To overcome this problem, a wide range of new Medium Access Control (MAC) protocols have been proposed for wireless networks. However, the speed of innovation in MAC protocols has not been able to keep up with the fast pace of PHY layer research; the latter being fueled by the availability of a variety of Software Defined Radio (SDR) platforms. These systems have eventually made their way into the classrooms and labs, thus giving communication engineers an experiential learning opportunity. They have provided students cost effective options to acquire real-world signals and analyze them using digital signal processing techniques. In essence, this has done for communications engineering students, what the sound card did for students learning audio signal processing. On the other hand, computer science students have been left with the option of learning about MAC protocols only through text books or by using software simulations. This is because most SDR systems do not meet the stringent latency and performance requirements required for creating real-world communication links; and the few that do are priced out of reach for classroom sizes typically found in Indian engineering colleges. In this paper, we analyze this situation at hand and discuss the emergence of a new design space for MAC layer prototyping systems. This paper discusses the key requirements, namely latency, processing speed, and cost, of systems in this design space. Finally, this paper describes how availability of commercial technology and careful trade-off with other requirements, such as throughput and frequency agility, is making it feasible to design a system that meets these key requirements.
{"title":"Latency and cost requirements of systems for teaching MAC protocols","authors":"A. Samant, Venkataramana Badarla, S. K. Yadav, Mythili Vutukuru, P. Khanna, Erik Luther","doi":"10.1109/NCC.2015.7084820","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084820","url":null,"abstract":"Over the past decade, the physical (PHY) layer of communication systems has evolved with the addition of techniques such as orthogonal frequency division multiplexing (OFDM) and multi-carrier aggregation. This has resulted in significant performance improvements, but it has come at the cost of increased power consumption and system complexity. To overcome this problem, a wide range of new Medium Access Control (MAC) protocols have been proposed for wireless networks. However, the speed of innovation in MAC protocols has not been able to keep up with the fast pace of PHY layer research; the latter being fueled by the availability of a variety of Software Defined Radio (SDR) platforms. These systems have eventually made their way into the classrooms and labs, thus giving communication engineers an experiential learning opportunity. They have provided students cost effective options to acquire real-world signals and analyze them using digital signal processing techniques. In essence, this has done for communications engineering students, what the sound card did for students learning audio signal processing. On the other hand, computer science students have been left with the option of learning about MAC protocols only through text books or by using software simulations. This is because most SDR systems do not meet the stringent latency and performance requirements required for creating real-world communication links; and the few that do are priced out of reach for classroom sizes typically found in Indian engineering colleges. In this paper, we analyze this situation at hand and discuss the emergence of a new design space for MAC layer prototyping systems. This paper discusses the key requirements, namely latency, processing speed, and cost, of systems in this design space. Finally, this paper describes how availability of commercial technology and careful trade-off with other requirements, such as throughput and frequency agility, is making it feasible to design a system that meets these key requirements.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"237 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115631307","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}
Three Dimensional (3-D) Underwater Acoustic Sensor Network (UASN) can be used to detect and observe ocean environment using co-operative and distributed sampling. We are proposing a multi-level clustering topology for ocean column monitoring application. A simple Cluster-Based TDMA MAC (CB-TDMA) protocol is simulated on this network using SUNSET platform developed by SENSES lab, Sapienza University, Rome. Analysis is provided in terms of packet delivery ratio, network delay and energy consumption. This CB-TDMA MAC along with multi-hop tri-message time synchronization is also implemented on a hardware test-bed in our laboratory. Brief description of this implementation is also provided in this paper.
三维(3-D)水声传感器网络(usasn)可以采用协同和分布式采样的方式对海洋环境进行探测和观测。提出了一种用于海洋柱监测的多级聚类拓扑结构。利用罗马Sapienza大学SENSES实验室开发的SUNSET平台，在该网络上模拟了一个简单的基于集群的TDMA MAC (CB-TDMA)协议。从分组传输率、网络时延和能耗等方面进行了分析。此CB-TDMA MAC以及多跳三消息时间同步也在我们实验室的硬件测试台上实现。本文还对该实现进行了简要描述。
{"title":"Simulation and testbed implementation of TDMA MAC on Underwater Acoustic Sensor Network","authors":"S. Dhongdi, K. Anupama, Rohit Agrawal, L. Gudino","doi":"10.1109/NCC.2015.7084868","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084868","url":null,"abstract":"Three Dimensional (3-D) Underwater Acoustic Sensor Network (UASN) can be used to detect and observe ocean environment using co-operative and distributed sampling. We are proposing a multi-level clustering topology for ocean column monitoring application. A simple Cluster-Based TDMA MAC (CB-TDMA) protocol is simulated on this network using SUNSET platform developed by SENSES lab, Sapienza University, Rome. Analysis is provided in terms of packet delivery ratio, network delay and energy consumption. This CB-TDMA MAC along with multi-hop tri-message time synchronization is also implemented on a hardware test-bed in our laboratory. Brief description of this implementation is also provided in this paper.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121079883","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}
We consider the channel allocation and routing problem for data transfer in wireless mesh networks with half duplex communication links. The interference constraints associated with channel allocation and the corresponding routing constraints are identified as a set of linear constraints. A mixed integer linear programming (MILP) formulation of the problem is then proposed to maximize the minimum spare capacity of each link. For networks of large size, we present sub-problems for channel allocation and routing and obtain a suboptimal solution for the problem. This method reduces the problem size thereby reducing the solving time. We analyze the problem for large networks with low traffic requirements and present some numerical results.
{"title":"Joint channel allocation and routing in wireless mesh networks","authors":"Sripada Kadambar, Tejas Bodas","doi":"10.1109/NCC.2015.7084847","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084847","url":null,"abstract":"We consider the channel allocation and routing problem for data transfer in wireless mesh networks with half duplex communication links. The interference constraints associated with channel allocation and the corresponding routing constraints are identified as a set of linear constraints. A mixed integer linear programming (MILP) formulation of the problem is then proposed to maximize the minimum spare capacity of each link. For networks of large size, we present sub-problems for channel allocation and routing and obtain a suboptimal solution for the problem. This method reduces the problem size thereby reducing the solving time. We analyze the problem for large networks with low traffic requirements and present some numerical results.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127120403","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}
In this paper, we obtain the maximum likelihood (ML) decision for a decode and forward (DF) cooperative system in Nakagami-m fading in the presence of co-channel interference at the relay as well as the destination. Through simulation results, we first show that conventional ML designed for interference free systems fails to combat the deleterious effect of interference. An optimum ML decision for combating interference is then derived for integer m. This receiver is shown to be superior to conventional ML through bit error rate (BER) performance simulations. Further, our results also indicate that optimum ML preserves relay diversity in the presence of interference.
{"title":"Maximum likelihood detection for decode and forward cooperation with interference","authors":"Y. Aditya, G. V. S. S. P. Varma, G. Sharma","doi":"10.1109/NCC.2015.7084814","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084814","url":null,"abstract":"In this paper, we obtain the maximum likelihood (ML) decision for a decode and forward (DF) cooperative system in Nakagami-m fading in the presence of co-channel interference at the relay as well as the destination. Through simulation results, we first show that conventional ML designed for interference free systems fails to combat the deleterious effect of interference. An optimum ML decision for combating interference is then derived for integer m. This receiver is shown to be superior to conventional ML through bit error rate (BER) performance simulations. Further, our results also indicate that optimum ML preserves relay diversity in the presence of interference.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127275680","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}
In this paper, we present a novel iterative median filter based strategy to improve the quality of the depth maps provided by sensors like Microsoft Kinect. The quality of the depth map is improved in two aspects, by filling holes present in the maps and by addressing the random noise. The holes are filled by iteratively applying a median based filter which takes into account the RGB components as well. The color similarity is measured by finding the absolute difference of the neighbourhood pixels and the median value. The hole filled depth map is further improved by applying a bilateral filter and processing the detail layer separately using Non-Local Denoising. The denoised detail layer is combined with the base layer to obtain a sharp and accurate depth map. We show that the proposed approach is able to generate high quality depth maps which can be quite useful in improving the performance of various applications of Microsoft Kinect such as pose estimation, gesture recognition, skeletal and facial tracking, etc.
{"title":"An iterative, non-local approach for restoring depth maps in RGB-D images","authors":"Akash Bapat, A. Ravi, S. Raman","doi":"10.1109/NCC.2015.7084819","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084819","url":null,"abstract":"In this paper, we present a novel iterative median filter based strategy to improve the quality of the depth maps provided by sensors like Microsoft Kinect. The quality of the depth map is improved in two aspects, by filling holes present in the maps and by addressing the random noise. The holes are filled by iteratively applying a median based filter which takes into account the RGB components as well. The color similarity is measured by finding the absolute difference of the neighbourhood pixels and the median value. The hole filled depth map is further improved by applying a bilateral filter and processing the detail layer separately using Non-Local Denoising. The denoised detail layer is combined with the base layer to obtain a sharp and accurate depth map. We show that the proposed approach is able to generate high quality depth maps which can be quite useful in improving the performance of various applications of Microsoft Kinect such as pose estimation, gesture recognition, skeletal and facial tracking, etc.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125160485","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}
In this work, we explore the task of musical onset detection in Carnatic music by choosing five major percussion instruments: the mridangam, ghatam, kanjira, morsing and thavil. We explore the musical characteristics of the strokes for each of the above instruments, motivating the challenge in designing an onset detection algorithm. We propose a non-model based algorithm using the minimum-phase group delay for this task. The music signal is treated as an Amplitude-Frequency modulated (AM-FM) waveform, and its envelope is extracted using the Hilbert transform. Minimum phase group delay processing is then applied to accurately determine the onset locations. The algorithm is tested on a large dataset with both controlled and concert recordings (tani avarthanams). The performance is observed to be the comparable with that of the state-of-the-art technique employing machine learning algorithms.
{"title":"Musical onset detection on carnatic percussion instruments","authors":"M. Kumar, J. Sebastian, H. Murthy","doi":"10.1109/NCC.2015.7084897","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084897","url":null,"abstract":"In this work, we explore the task of musical onset detection in Carnatic music by choosing five major percussion instruments: the mridangam, ghatam, kanjira, morsing and thavil. We explore the musical characteristics of the strokes for each of the above instruments, motivating the challenge in designing an onset detection algorithm. We propose a non-model based algorithm using the minimum-phase group delay for this task. The music signal is treated as an Amplitude-Frequency modulated (AM-FM) waveform, and its envelope is extracted using the Hilbert transform. Minimum phase group delay processing is then applied to accurately determine the onset locations. The algorithm is tested on a large dataset with both controlled and concert recordings (tani avarthanams). The performance is observed to be the comparable with that of the state-of-the-art technique employing machine learning algorithms.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123285368","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}
Supervised approaches for speech enhancement require models to be learned for different noisy environments, which is a difficult criterion to meet in practical scenarios. In this paper, compressed sensing (CS) based supervised speech enhancement approach is proposed, where model (dictionary) for noise is derived from the noisy speech signal. It exploits the observation that unvoiced/silence regions of noisy speech signal will be predominantly noise and a method is proposed to measure the same, thus eliminating pre-training of noise model. The proposed method is particularly effective in scenarios where noise type is not known a priori. Experimental results validate that the proposed approach can be an alternative to the existing approaches for speech enhancement.
{"title":"Supervised speech enhancement using compressed sensing","authors":"Pulkit Sharma, V. Abrol, A. Sao","doi":"10.1109/NCC.2015.7084919","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084919","url":null,"abstract":"Supervised approaches for speech enhancement require models to be learned for different noisy environments, which is a difficult criterion to meet in practical scenarios. In this paper, compressed sensing (CS) based supervised speech enhancement approach is proposed, where model (dictionary) for noise is derived from the noisy speech signal. It exploits the observation that unvoiced/silence regions of noisy speech signal will be predominantly noise and a method is proposed to measure the same, thus eliminating pre-training of noise model. The proposed method is particularly effective in scenarios where noise type is not known a priori. Experimental results validate that the proposed approach can be an alternative to the existing approaches for speech enhancement.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126824658","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}
Rateless Codes are effective in reducing the costs of retransmissions over erasure channels. Some rateless codes have systematic leading parts which have been shown in the literature to enhance their performance. The systematic part allows a node to start transmitting packets as soon as they are received without waiting for the entire multi-packet message to be decoded. This will naturally reduce the end-to-end delay which is critical for streaming applications. Using systematic rateless codes, this paper proposes a network routing algorithm to reduce streaming delays. The algorithm is easy to analyze and implement. Its performance is studied and compared against the existing algorithms through simulations in network scenarios where the nodes use systematic rateless codes for communication.
{"title":"Network routing for streaming applications using systematic rateless codes","authors":"Sonu K. Mishra, Soumya Indela, S. Bose, W. Zhong","doi":"10.1109/NCC.2015.7084832","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084832","url":null,"abstract":"Rateless Codes are effective in reducing the costs of retransmissions over erasure channels. Some rateless codes have systematic leading parts which have been shown in the literature to enhance their performance. The systematic part allows a node to start transmitting packets as soon as they are received without waiting for the entire multi-packet message to be decoded. This will naturally reduce the end-to-end delay which is critical for streaming applications. Using systematic rateless codes, this paper proposes a network routing algorithm to reduce streaming delays. The algorithm is easy to analyze and implement. Its performance is studied and compared against the existing algorithms through simulations in network scenarios where the nodes use systematic rateless codes for communication.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116579891","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 novel and compact dual band partial ground coplanar waveguide (CPW) fed monopole modified elliptical antenna design is proposed. Dual band antenna is designed to cover both WLAN band at 2.4 GHz and WiMAX band at 3.5 GHz. Antenna exhibits good return loss characteristics in both the bands. Antenna is designed on RT/Duroid 5880 with dielectric constant 2.2, thickness 1.6 mm and loss tangent 0.0009 to improve the efficiency. Antenna parameters are optimized with respect to dual band characteristics. Based on these optimized parameters antenna prototype is fabricated. Radiation pattern of the proposed antenna is quasi semi-omnidirectional. Parallel agreement between simulated and measured results makes the proposed dual band antenna suitable candidate for modern wireless communication systems.
{"title":"A novel and compact dual band antenna using modified elliptical ring monopole","authors":"A. Kamma, Kaustubh Chhabilwad, G. Reddy, J. Mukherjee","doi":"10.1109/NCC.2015.7084828","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084828","url":null,"abstract":"A novel and compact dual band partial ground coplanar waveguide (CPW) fed monopole modified elliptical antenna design is proposed. Dual band antenna is designed to cover both WLAN band at 2.4 GHz and WiMAX band at 3.5 GHz. Antenna exhibits good return loss characteristics in both the bands. Antenna is designed on RT/Duroid 5880 with dielectric constant 2.2, thickness 1.6 mm and loss tangent 0.0009 to improve the efficiency. Antenna parameters are optimized with respect to dual band characteristics. Based on these optimized parameters antenna prototype is fabricated. Radiation pattern of the proposed antenna is quasi semi-omnidirectional. Parallel agreement between simulated and measured results makes the proposed dual band antenna suitable candidate for modern wireless communication systems.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"55 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114117779","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}
Viterbi detector is widely used in communication systems for signal detection. The exact performance of the detector is of research interest ever since the algorithm was proposed. Traditional methods to characterize the performance bound the bit error rate (BER) of the detector using error event analysis and minimum distance bounds. A Markovian approach was proposed to exactly characterize the performance of Viterbi decoder for convolutional codes. In this paper, we model the signal detection process for quantized ISI channels as a hidden Markov model (HMM) for evaluating the exact performance of the detector. We describe a procedure to obtain an exact closed form expression for BER of the detector for quantized ISI channels.
{"title":"Exact analysis of the performance of viterbi detector for ISI channels with quantized inputs","authors":"C. Matcha, S. G. Srinivasa","doi":"10.1109/NCC.2015.7084850","DOIUrl":"https://doi.org/10.1109/NCC.2015.7084850","url":null,"abstract":"Viterbi detector is widely used in communication systems for signal detection. The exact performance of the detector is of research interest ever since the algorithm was proposed. Traditional methods to characterize the performance bound the bit error rate (BER) of the detector using error event analysis and minimum distance bounds. A Markovian approach was proposed to exactly characterize the performance of Viterbi decoder for convolutional codes. In this paper, we model the signal detection process for quantized ISI channels as a hidden Markov model (HMM) for evaluating the exact performance of the detector. We describe a procedure to obtain an exact closed form expression for BER of the detector for quantized ISI channels.","PeriodicalId":302718,"journal":{"name":"2015 Twenty First National Conference on Communications (NCC)","volume":"228 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124521142","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：