Pub Date : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503798
Hai Li, Y. Liu
The motivation of this work is to examine how well methods, such as successive interference cancellation and interference alignment from information theoretic solution, work in real-world where the received signal is quantized for digital processing. As a first step, we consider Gaussian Multiple Access Channels with the quantization noise modeled as Gaussian noise, whose variance depends on the received signal power at the receiver. We call this model Gaussian Multiple Access Channel with Signal Dependent Noise. The achievable rate region of this model is given under finite transmitted signal power constraint, where the achievable scheme could be successive interference cancellation (SIC). This region is outer bounded by a finite region with unlimited received signal power, where the achievable scheme is time division multiple access (TDMA). Thus, one way to measure the usefulness of successive interference cancellation is to study the gap between the SIC region and the TDMA region under finite power constraints. For the symmetric maximum signal to channel noise ratio (SCNR) case, where the maximum SCNR of all users are the same, we show that the gap between the SIC region and the TDMA region is within 0.5 bits for any number of users. Furthermore, for this case, if the maximum quantization noise power due to one user is stronger than the channel noise power, then the sum rate difference between the SIC region and the TDMA region is within 0.5 bits. For the asymmetric maximum SCNR case, the gap can be small when all users have high SCNR (e.g., 30dB), where the receiver is equipped with a low precision ADC (e.g., 2–3 bits).
{"title":"On Gaussian Multiple Access Channel with Signal Dependent Noise","authors":"Hai Li, Y. Liu","doi":"10.1109/GLOCOM.2012.6503798","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503798","url":null,"abstract":"The motivation of this work is to examine how well methods, such as successive interference cancellation and interference alignment from information theoretic solution, work in real-world where the received signal is quantized for digital processing. As a first step, we consider Gaussian Multiple Access Channels with the quantization noise modeled as Gaussian noise, whose variance depends on the received signal power at the receiver. We call this model Gaussian Multiple Access Channel with Signal Dependent Noise. The achievable rate region of this model is given under finite transmitted signal power constraint, where the achievable scheme could be successive interference cancellation (SIC). This region is outer bounded by a finite region with unlimited received signal power, where the achievable scheme is time division multiple access (TDMA). Thus, one way to measure the usefulness of successive interference cancellation is to study the gap between the SIC region and the TDMA region under finite power constraints. For the symmetric maximum signal to channel noise ratio (SCNR) case, where the maximum SCNR of all users are the same, we show that the gap between the SIC region and the TDMA region is within 0.5 bits for any number of users. Furthermore, for this case, if the maximum quantization noise power due to one user is stronger than the channel noise power, then the sum rate difference between the SIC region and the TDMA region is within 0.5 bits. For the asymmetric maximum SCNR case, the gap can be small when all users have high SCNR (e.g., 30dB), where the receiver is equipped with a low precision ADC (e.g., 2–3 bits).","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"12 1","pages":"4326-4331"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86301695","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 : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503082
J. Tsai, Yen-Cheng Li
Greedy forwarding combined with planar graph routing exploits minimal local position information to achieve reliable packet delivery in wireless networks. However, it is at the expense of path hop counts and traffic loads converging on links dictated by a chosen planar graph traversal scheme to bypass network holes. To mitigate these negative factors for delay-sensitive traffic service, our forwarding scheme further utilizes a simple hypothesis test based on local information to partition the set of candidate neighborhood nodes for packet relay into two subsets. One is a preferable subset containing nodes more likely located in a dense area of nodes and less likely to be a local minimum for greedy forwarding while the other contains the rest. The preferable subset has priority over the other one in the process of greedy forwarding. Consequently, our geographic routing scheme even embodies the feature of quasi greedy for forwarding packets but does achieve the goal of reducing routing hop counts. It only requires an extra complexity at each node to compute a representative angle that characterizes the node and to interchange with neighborhood nodes the angle information in addition to the location information needed normally.
{"title":"Quasi-greedy geographic routing in wireless networks","authors":"J. Tsai, Yen-Cheng Li","doi":"10.1109/GLOCOM.2012.6503082","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503082","url":null,"abstract":"Greedy forwarding combined with planar graph routing exploits minimal local position information to achieve reliable packet delivery in wireless networks. However, it is at the expense of path hop counts and traffic loads converging on links dictated by a chosen planar graph traversal scheme to bypass network holes. To mitigate these negative factors for delay-sensitive traffic service, our forwarding scheme further utilizes a simple hypothesis test based on local information to partition the set of candidate neighborhood nodes for packet relay into two subsets. One is a preferable subset containing nodes more likely located in a dense area of nodes and less likely to be a local minimum for greedy forwarding while the other contains the rest. The preferable subset has priority over the other one in the process of greedy forwarding. Consequently, our geographic routing scheme even embodies the feature of quasi greedy for forwarding packets but does achieve the goal of reducing routing hop counts. It only requires an extra complexity at each node to compute a representative angle that characterizes the node and to interchange with neighborhood nodes the angle information in addition to the location information needed normally.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"5 1","pages":"8-13"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83441196","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 : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503367
Ching-Chun Kuan, Hung-Yu Wei
In this paper, we study the reliable broadcast transmission in energy harvesting networks. In addition to employ the erasure-based coding scheme to cope with the packet loss, we deal with the main challenge posed to a reliable transmission in energy harvesting networks: energy deficiency. It refers that the energy harvesting node cannot work when its battery is exhausted. Hence, we take both transmission error and energy deficiency into account and propose a theoretical analysis and a system design for reliable broadcast transmissions. We also investigate the performance trade-off between reliability and throughput. For different requirements, we propose the reliability-first policy and the throughput-first policy to determine the system parameters.
{"title":"Design and analysis for reliable broadcast transmission in energy harvesting networks","authors":"Ching-Chun Kuan, Hung-Yu Wei","doi":"10.1109/GLOCOM.2012.6503367","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503367","url":null,"abstract":"In this paper, we study the reliable broadcast transmission in energy harvesting networks. In addition to employ the erasure-based coding scheme to cope with the packet loss, we deal with the main challenge posed to a reliable transmission in energy harvesting networks: energy deficiency. It refers that the energy harvesting node cannot work when its battery is exhausted. Hence, we take both transmission error and energy deficiency into account and propose a theoretical analysis and a system design for reliable broadcast transmissions. We also investigate the performance trade-off between reliability and throughput. For different requirements, we propose the reliability-first policy and the throughput-first policy to determine the system parameters.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"9 1","pages":"1745-1750"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75870718","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 : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503870
Zheqi Gu, Ning Wei, Zhong-pei Zhang
The timing synchronization reciprocity error(TSRE) is modeled and investigated in this paper, which can be found in an OFDM/TDD coordinated multi-point transmission(CoMP) system. In order to avoid its adverse impact on the radio frequency(RF) calibration, we improve the traditional calibration algorithm. Moreover, we propose two robust precoding schemes to alleviate the performance degradation of the multi-user CoMP system caused by the TSRE. The design criteria of these precoding schemes are based on compensating the linear phase rotation at every subcarrier and maximizing the lower bound of the average signal-to-leakage-plus-noise ratio(SLNR). Simulation results demonstrate that the proposed robust precoding schemes can achieve higher system throughput than the conventional SLNR precoding scheme under the non-ideal reciprocity situation.
{"title":"Timing synchronization reciprocity error cancellation in OFDM/TDD coordinated multi-point transmission system","authors":"Zheqi Gu, Ning Wei, Zhong-pei Zhang","doi":"10.1109/GLOCOM.2012.6503870","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503870","url":null,"abstract":"The timing synchronization reciprocity error(TSRE) is modeled and investigated in this paper, which can be found in an OFDM/TDD coordinated multi-point transmission(CoMP) system. In order to avoid its adverse impact on the radio frequency(RF) calibration, we improve the traditional calibration algorithm. Moreover, we propose two robust precoding schemes to alleviate the performance degradation of the multi-user CoMP system caused by the TSRE. The design criteria of these precoding schemes are based on compensating the linear phase rotation at every subcarrier and maximizing the lower bound of the average signal-to-leakage-plus-noise ratio(SLNR). Simulation results demonstrate that the proposed robust precoding schemes can achieve higher system throughput than the conventional SLNR precoding scheme under the non-ideal reciprocity situation.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"56 1","pages":"4752-4757"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90457627","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 : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503873
Wen-Chao Zheng, Long Zhang, Qing-Xia Li, Yuan Zhou, Rong Rong
A novel compact size dual-band dual-polarized antenna array for MIMO WLAN is reported. The array element comprises a periodic antenna with bowtie dipoles and a printed dipole antenna with a reflector and a director. The presented design is characterized by dual-band operation, good front-to-back ratios, average gains of 4 and 5 dBi over the 2.4 and 5.2 GHz bands respectively. A prototype 12-element array exhibits dual broad bandwidth and low mutual coupling among 2.25GHz–2.6GHz and 4.95GHz–6GHz. The measured results indicate the array is suitable for 802.11a/b/g/n systems employing MIMO and beam selection techniques.
{"title":"Dual-band dual-polarized antenna array for beam selection MIMO WLAN","authors":"Wen-Chao Zheng, Long Zhang, Qing-Xia Li, Yuan Zhou, Rong Rong","doi":"10.1109/GLOCOM.2012.6503873","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503873","url":null,"abstract":"A novel compact size dual-band dual-polarized antenna array for MIMO WLAN is reported. The array element comprises a periodic antenna with bowtie dipoles and a printed dipole antenna with a reflector and a director. The presented design is characterized by dual-band operation, good front-to-back ratios, average gains of 4 and 5 dBi over the 2.4 and 5.2 GHz bands respectively. A prototype 12-element array exhibits dual broad bandwidth and low mutual coupling among 2.25GHz–2.6GHz and 4.95GHz–6GHz. The measured results indicate the array is suitable for 802.11a/b/g/n systems employing MIMO and beam selection techniques.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"30 1","pages":"4770-4774"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75526900","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 : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503909
Miaowen Wen, Xiang Cheng, Zhongshan Zhang, Xiaohui Duan, B. Jiao
In this paper, we present an analytical study of the bit error rate (BER) for interleaved single-carrier frequency-division multiple access (SC-FDMA) systems over independent but not necessarily identically distributed (i.n.i.d.) Nakagami-m fading channels with fading parameters {m} being integers when minimum mean-square error frequency-domain equalization (MMSE-FDE) is applied. Under the assumption of independent fading characteristics among channel frequency responses (CFRs) at the allocated subcarriers for a specific user, accurate numerical BER computation for square M-ary quadrature amplitude modulation (M-QAM) is developed by exploiting the statistics of the equalized noise. More importantly, the BER derivation is based on the real distribution of the CFRs without applying the widely used approximation of the CFRs in previous literature, resulting in a more accurate BER analysis. Monte-Carlo simulations are conducted to validate the analysis.
{"title":"BER analysis for MMSE-FDE-based interleaved SC-FDMA systems over Nakagami-m fading channels","authors":"Miaowen Wen, Xiang Cheng, Zhongshan Zhang, Xiaohui Duan, B. Jiao","doi":"10.1109/GLOCOM.2012.6503909","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503909","url":null,"abstract":"In this paper, we present an analytical study of the bit error rate (BER) for interleaved single-carrier frequency-division multiple access (SC-FDMA) systems over independent but not necessarily identically distributed (i.n.i.d.) Nakagami-m fading channels with fading parameters {m} being integers when minimum mean-square error frequency-domain equalization (MMSE-FDE) is applied. Under the assumption of independent fading characteristics among channel frequency responses (CFRs) at the allocated subcarriers for a specific user, accurate numerical BER computation for square M-ary quadrature amplitude modulation (M-QAM) is developed by exploiting the statistics of the equalized noise. More importantly, the BER derivation is based on the real distribution of the CFRs without applying the widely used approximation of the CFRs in previous literature, resulting in a more accurate BER analysis. Monte-Carlo simulations are conducted to validate the analysis.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"14 1","pages":"4981-4986"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/GLOCOM.2012.6503909","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72469097","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 : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503835
Zhengfeng Xu, Pingyi Fan, Hong-Chuan Yang, Ke Xiong, M. Lei, Su Yi
Multiple input multiple output (MIMO) relay channels has great application potentials in wireless communication systems and therefore attracts both academia and industrial attentions recently. In this paper, we consider the MIMO relay channels where both source node and relay node are equipped with multiple antennas and the destination node has a single antenna. We address the optimal beamforming design when decode-and-forward half-duplex relaying protocol is deployed. Specifically, we develop an efficient algorithm to determine the optimal beamforming vector at the source when transmitting to relay and destination at the same time. Based on the exact channel capacity formulation, the proposed algorithm can achieve arbitrarily high accuracy with low computational complexity.
{"title":"Optimal beamforming for MIMO decode-and-forward relay channels","authors":"Zhengfeng Xu, Pingyi Fan, Hong-Chuan Yang, Ke Xiong, M. Lei, Su Yi","doi":"10.1109/GLOCOM.2012.6503835","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503835","url":null,"abstract":"Multiple input multiple output (MIMO) relay channels has great application potentials in wireless communication systems and therefore attracts both academia and industrial attentions recently. In this paper, we consider the MIMO relay channels where both source node and relay node are equipped with multiple antennas and the destination node has a single antenna. We address the optimal beamforming design when decode-and-forward half-duplex relaying protocol is deployed. Specifically, we develop an efficient algorithm to determine the optimal beamforming vector at the source when transmitting to relay and destination at the same time. Based on the exact channel capacity formulation, the proposed algorithm can achieve arbitrarily high accuracy with low computational complexity.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"41 1","pages":"4548-4553"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81918331","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 : 2012-12-01DOI: 10.1109/GLOCOM.2012.6503596
Nga T. Dinh, A. Elwalid
Reducing power consumption in access networks has become an increasingly important design goal due to increased concerns for both global warming and network operation costs. Although passive optical networks (PONs) consume the least power among all access network technologies, it is desirable to further reduce PON's power consumption, especially when the line rate is being increased to 10Gbps (10G) and wider deployment is underway. Generally, an effective approach to reduce power consumption is to use sleep-mode operation where functionality is powered off during periods of idleness. This paper therefore proposes a sleep-mode based power saving protocol applied to an optical line terminal (OLT) and optical network units (ONUs) to implement ONU power saving in 10G-Ethernet-PON (10G-EPON) systems. The proposed protocol explicitly distinguishes sleep-, listen-, and awake- states with different power consumption levels. In addition, the paper proposes analytical models for ONU power consumption and response delay to evaluate performance of the proposed power saving protocol. The simulations show that the proposed protocol can significantly improve ONU power saving. The validity of the numerical models is also confirmed by extensive simulations.
{"title":"Power saving protocol for 10G- EPON systems: A proposal and performance evaluations","authors":"Nga T. Dinh, A. Elwalid","doi":"10.1109/GLOCOM.2012.6503596","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503596","url":null,"abstract":"Reducing power consumption in access networks has become an increasingly important design goal due to increased concerns for both global warming and network operation costs. Although passive optical networks (PONs) consume the least power among all access network technologies, it is desirable to further reduce PON's power consumption, especially when the line rate is being increased to 10Gbps (10G) and wider deployment is underway. Generally, an effective approach to reduce power consumption is to use sleep-mode operation where functionality is powered off during periods of idleness. This paper therefore proposes a sleep-mode based power saving protocol applied to an optical line terminal (OLT) and optical network units (ONUs) to implement ONU power saving in 10G-Ethernet-PON (10G-EPON) systems. The proposed protocol explicitly distinguishes sleep-, listen-, and awake- states with different power consumption levels. In addition, the paper proposes analytical models for ONU power consumption and response delay to evaluate performance of the proposed power saving protocol. The simulations show that the proposed protocol can significantly improve ONU power saving. The validity of the numerical models is also confirmed by extensive simulations.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"53 1","pages":"3135-3140"},"PeriodicalIF":0.0,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90993002","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 : 2012-01-01DOI: 10.1109/GLOCOM.2012.6503869
Si Liu, B. Liu, Xiaoqiang Ma, Bo Rong, Lin Gui
This paper proposes an algorithm of data subcarrier designing to apply the tone reservation(TR) peak-to-average power ratio (PAPR) reduction algorithm in OFDM-based wireless communication systems and overcome the high computational cost issue. Different from the existing works, the proposed algorithm focuses on designing data subcarriers, controlling both the iteration times and the number of subcarriers. The new algorithm exhibits similar performance as the traditional TR algorithm with lower computational complexity and the ability to control the number of used subcarriers. Simulation results show that the proposed algorithm can significantly reduce the PAPR by only 2 or 3 iterations.
{"title":"Low-complexity PAPR reduction algorithm in OFDM systems by designing data subcarriers","authors":"Si Liu, B. Liu, Xiaoqiang Ma, Bo Rong, Lin Gui","doi":"10.1109/GLOCOM.2012.6503869","DOIUrl":"https://doi.org/10.1109/GLOCOM.2012.6503869","url":null,"abstract":"This paper proposes an algorithm of data subcarrier designing to apply the tone reservation(TR) peak-to-average power ratio (PAPR) reduction algorithm in OFDM-based wireless communication systems and overcome the high computational cost issue. Different from the existing works, the proposed algorithm focuses on designing data subcarriers, controlling both the iteration times and the number of subcarriers. The new algorithm exhibits similar performance as the traditional TR algorithm with lower computational complexity and the ability to control the number of used subcarriers. Simulation results show that the proposed algorithm can significantly reduce the PAPR by only 2 or 3 iterations.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"CE-24 1","pages":"4747-4751"},"PeriodicalIF":0.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84563482","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 : 2010-12-01DOI: 10.1109/GLOCOMW.2010.5700118
Ruben de Francisco
In cognitive radios, spectrum sensing is employed as a means to increase spectrum usage awareness. Spectrum sensing algorithms must satisfy the desired performance requirements, in terms of probability of detection and false alarm, with short sensing duration. In addition, low-complexity algorithms are sought, particularly in low-power cognitive radios. A mechanism to search available channels in the frequency domain is proposed in this paper. Rather than obtaining an accurate estimation of the spectrum within a certain frequency range, we focus here on the task of finding white spaces. The proposed technique is a steepest descent method, adapted to the problem of sensing white spaces. Based on an approximation on the right and left derivatives of a smoothed periodogram, the algorithm iteratively searches for a free channel by following the direction of steepest descent. The adaptation step is such that the algorithm produces large steps in flat spectrum regions and small steps in steep regions, in order not to miss narrow portions of the spectrum with free channels. Simulations are provided for the proposed algorithm in a scenario where IEEE 802.11g and IEEE 802.15.4 devices coexist. The performance and speed of convergence of the proposed algorithm are shown, providing a comparison with a system that performs random channel search.
{"title":"Sequential search of available channels in cognitive radios","authors":"Ruben de Francisco","doi":"10.1109/GLOCOMW.2010.5700118","DOIUrl":"https://doi.org/10.1109/GLOCOMW.2010.5700118","url":null,"abstract":"In cognitive radios, spectrum sensing is employed as a means to increase spectrum usage awareness. Spectrum sensing algorithms must satisfy the desired performance requirements, in terms of probability of detection and false alarm, with short sensing duration. In addition, low-complexity algorithms are sought, particularly in low-power cognitive radios. A mechanism to search available channels in the frequency domain is proposed in this paper. Rather than obtaining an accurate estimation of the spectrum within a certain frequency range, we focus here on the task of finding white spaces. The proposed technique is a steepest descent method, adapted to the problem of sensing white spaces. Based on an approximation on the right and left derivatives of a smoothed periodogram, the algorithm iteratively searches for a free channel by following the direction of steepest descent. The adaptation step is such that the algorithm produces large steps in flat spectrum regions and small steps in steep regions, in order not to miss narrow portions of the spectrum with free channels. Simulations are provided for the proposed algorithm in a scenario where IEEE 802.11g and IEEE 802.15.4 devices coexist. The performance and speed of convergence of the proposed algorithm are shown, providing a comparison with a system that performs random channel search.","PeriodicalId":72021,"journal":{"name":"... IEEE Global Communications Conference. IEEE Global Communications Conference","volume":"449 3 1","pages":"1162-1166"},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77904930","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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