Pub Date : 2007-11-21DOI: 10.1109/SIPS.2007.4387586
Chi-Li Yu, T. Yu, A. Wu
A novel analysis methodology on the quantization effect of existing CORDIC algorithms is presented. Based on the methodology, we first verified that MSR-CORDIC is a much favorable candidate for rotation-based applications due to its high numerical precision. Then, a new design flow is proposed to determine an ideal configuration for MSR-CORDIC with optimized accuracy performance under the same hardware cost. This would benefit many rotation-based DSP applications, such as FFT, QRD, and EVD.
{"title":"On the Fixed-Point Properties of Mixed-Scaling-Rotation Cordic Algorithm","authors":"Chi-Li Yu, T. Yu, A. Wu","doi":"10.1109/SIPS.2007.4387586","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387586","url":null,"abstract":"A novel analysis methodology on the quantization effect of existing CORDIC algorithms is presented. Based on the methodology, we first verified that MSR-CORDIC is a much favorable candidate for rotation-based applications due to its high numerical precision. Then, a new design flow is proposed to determine an ideal configuration for MSR-CORDIC with optimized accuracy performance under the same hardware cost. This would benefit many rotation-based DSP applications, such as FFT, QRD, and EVD.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"9 1","pages":"430-435"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81797731","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387511
Zhengya Zhang, R. Winoto, A. Bahai, B. Nikolić
Digital predistortion is a technique used to reduce the signal dynamic range in a multichannel system in order to improve power amplifier (PA) efficiency. These techniques have been developed for orthogonal frequency-division multi-plexing (OFDM) systems, but are not directly applicable to general frequency-division multiplexing (FDM) systems such as those used in broadcast. A modification to the tone injection approach allows constellation translations to be directly applied at the digital intermediate frequency (IF) domain and provides redundancy in lowering peak-to-average ratio (PAR). Simulation of a 24-channel 256-QAM FDM cable television transmission system shows a 3.3 dB PAR reduction at 10-6 clipping probability.
{"title":"Peak-to-Average Power Ratio Reduction in an FDM Broadcast System","authors":"Zhengya Zhang, R. Winoto, A. Bahai, B. Nikolić","doi":"10.1109/SIPS.2007.4387511","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387511","url":null,"abstract":"Digital predistortion is a technique used to reduce the signal dynamic range in a multichannel system in order to improve power amplifier (PA) efficiency. These techniques have been developed for orthogonal frequency-division multi-plexing (OFDM) systems, but are not directly applicable to general frequency-division multiplexing (FDM) systems such as those used in broadcast. A modification to the tone injection approach allows constellation translations to be directly applied at the digital intermediate frequency (IF) domain and provides redundancy in lowering peak-to-average ratio (PAR). Simulation of a 24-channel 256-QAM FDM cable television transmission system shows a 3.3 dB PAR reduction at 10-6 clipping probability.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"45 1","pages":"25-30"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80255244","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387507
Zhuan Ye, J. Grosspietsch, G. Memik
Cognitive radios (CR) are proposed to alleviate the spectrum scarcity problems facing wireless service providers. In US, the FCC is considering spectrum regulation changes by allowing unlicensed operation in the TV broadcast bands provided that no harmful interference is caused. In this paper, we discuss the spectrum sensing aspects of cognitive radios. We particularly focus on the detection method based on cyclostationary spectrum density (CSD) estimation. The advantage of CSD is its relative robustness against noise uncertainty compared with energy detection methods. CSD estimation is a two dimensional transformation; therefore it is computationally complex. We transform the algorithm from the two dimensional space to a one dimensional case, therefore making the real time implementation more feasible. Through analysis and simulation, we identify the features with highest SNR to be used for CSD based detection. Based on the simulation results, we further propose dedicated hardware implementation architecture for CSD estimation using field programmable logic array (FPGA). Our implementation can achieve greater than 90% detection probability on BPSK signals with SNR of -18 dB, when the probability of false alarm is less than 10%.
{"title":"Spectrum Sensing Using Cyclostationary Spectrum Density for Cognitive Radios","authors":"Zhuan Ye, J. Grosspietsch, G. Memik","doi":"10.1109/SIPS.2007.4387507","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387507","url":null,"abstract":"Cognitive radios (CR) are proposed to alleviate the spectrum scarcity problems facing wireless service providers. In US, the FCC is considering spectrum regulation changes by allowing unlicensed operation in the TV broadcast bands provided that no harmful interference is caused. In this paper, we discuss the spectrum sensing aspects of cognitive radios. We particularly focus on the detection method based on cyclostationary spectrum density (CSD) estimation. The advantage of CSD is its relative robustness against noise uncertainty compared with energy detection methods. CSD estimation is a two dimensional transformation; therefore it is computationally complex. We transform the algorithm from the two dimensional space to a one dimensional case, therefore making the real time implementation more feasible. Through analysis and simulation, we identify the features with highest SNR to be used for CSD based detection. Based on the simulation results, we further propose dedicated hardware implementation architecture for CSD estimation using field programmable logic array (FPGA). Our implementation can achieve greater than 90% detection probability on BPSK signals with SNR of -18 dB, when the probability of false alarm is less than 10%.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"44 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80407640","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387598
Jin Ho Ha, Jin Soo Kim, M. Sunwoo
We present an ASIP (application-specific instruction-set processor) approach for H.264 implementation having novel coprocessors. We have previously proposed the video specific instruction-set processor (VSIP) for H.264/AVC. To improve performance of motion estimation (ME) further, we propose a new improved ME accelerator using the modified normalized partial distortion search (MNPDS) algorithm. The proposed MNPDS can reduce the average computational complexity by 96.2-99.5% compared to the full search algorithm whereas the PSNR decreases only 0.04 dB. Hence, VSIP using MNPDS is one of promising candidates for real-time video processing.
{"title":"AN ASIP Approach for H.264/AVC Implementation Having Novel Coprocessors","authors":"Jin Ho Ha, Jin Soo Kim, M. Sunwoo","doi":"10.1109/SIPS.2007.4387598","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387598","url":null,"abstract":"We present an ASIP (application-specific instruction-set processor) approach for H.264 implementation having novel coprocessors. We have previously proposed the video specific instruction-set processor (VSIP) for H.264/AVC. To improve performance of motion estimation (ME) further, we propose a new improved ME accelerator using the modified normalized partial distortion search (MNPDS) algorithm. The proposed MNPDS can reduce the average computational complexity by 96.2-99.5% compared to the full search algorithm whereas the PSNR decreases only 0.04 dB. Hence, VSIP using MNPDS is one of promising candidates for real-time video processing.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"23 1","pages":"499-504"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81562415","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387605
F. Flitti, A. Bermak
This paper deals with face detection in still gray level images which is the first step in many automatic systems like video surveillance, face recognition, and images data base management. We propose a new face detection method using a classifiers cascade, each of which is based on a vector angle similarity measure between the investigated window and the face and nonface representatives (centroids). The latter are obtained using a clustering algorithm based on the same measure within the current training data sets, namely the low confidence classified samples at the previous stage of the cascade. First experiment results on refereed face data test sets are very satisfactory.
{"title":"Face Detection Using Classifiers Cascade Based on Vector Angle Measure and Multi-Modal Representation","authors":"F. Flitti, A. Bermak","doi":"10.1109/SIPS.2007.4387605","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387605","url":null,"abstract":"This paper deals with face detection in still gray level images which is the first step in many automatic systems like video surveillance, face recognition, and images data base management. We propose a new face detection method using a classifiers cascade, each of which is based on a vector angle similarity measure between the investigated window and the face and nonface representatives (centroids). The latter are obtained using a clustering algorithm based on the same measure within the current training data sets, namely the low confidence classified samples at the previous stage of the cascade. First experiment results on refereed face data test sets are very satisfactory.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"22 1","pages":"539-542"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80957197","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387621
I. M. Mahafeno, L. Conde-Canencia, E. Boutillon
In this paper, an original low-complexity technique for fast PN code acquisition is proposed. Its major advantage is that the receiver does not need to know the PN code itself, but only its length. We have applied the proposed technique in the context of GNSS receivers, and more specifically to Galileo, the European contribution to GNSS. The analysis of its performances (mainly in realistic environments) shows that the proposed technique significantly accelerates the signal acquisition process since it greatly reduces the search space. In fact, the correlation process in the synchronization step is no longer carried out for the whole data sequence but within a window of small length, which can be about 100 times smaller than the code length. Moreover, its architecture has a low cost implementation.
{"title":"Coarse Self-Synchronization Technique for GNSS Receivers","authors":"I. M. Mahafeno, L. Conde-Canencia, E. Boutillon","doi":"10.1109/SIPS.2007.4387621","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387621","url":null,"abstract":"In this paper, an original low-complexity technique for fast PN code acquisition is proposed. Its major advantage is that the receiver does not need to know the PN code itself, but only its length. We have applied the proposed technique in the context of GNSS receivers, and more specifically to Galileo, the European contribution to GNSS. The analysis of its performances (mainly in realistic environments) shows that the proposed technique significantly accelerates the signal acquisition process since it greatly reduces the search space. In fact, the correlation process in the synchronization step is no longer carried out for the whole data sequence but within a window of small length, which can be about 100 times smaller than the code length. Moreover, its architecture has a low cost implementation.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"113 1","pages":"621-626"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86766978","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387581
Chun-Yuan Chu, J. Lai, A. Wu
We propose a robust auto gain control (AGC) algorithm for OFDM-based ultra-wideband (UWB) system. In the UWB system, the transmitted signal power is limited to -41.25 dBm in a 1-MHz bandwidth. Therefore, it is difficult for front-end receiver operation by using traditional power estimation approach. Based on the proposed packet detector (PD), the signal power estimation is much more accurate. On the other hand, saturation of the ADC output is another critical issue. We provide a robust AGC convergence mechanism solving this problem. After the AGC operation converges, the received signal power is within the error margin relative to target power. This power error is less than 0.5 dB.
{"title":"Robust Packet Detector based Automatic Gain Control Algorithm for OFDM-based Ultra-WideBand systems","authors":"Chun-Yuan Chu, J. Lai, A. Wu","doi":"10.1109/SIPS.2007.4387581","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387581","url":null,"abstract":"We propose a robust auto gain control (AGC) algorithm for OFDM-based ultra-wideband (UWB) system. In the UWB system, the transmitted signal power is limited to -41.25 dBm in a 1-MHz bandwidth. Therefore, it is difficult for front-end receiver operation by using traditional power estimation approach. Based on the proposed packet detector (PD), the signal power estimation is much more accurate. On the other hand, saturation of the ADC output is another critical issue. We provide a robust AGC convergence mechanism solving this problem. After the AGC operation converges, the received signal power is within the error margin relative to target power. This power error is less than 0.5 dB.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"520 1","pages":"403-406"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77210560","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387515
Hsiu-Chi Chang, Yen-Chin Liao, Hsie-Chia Chang
In multiple-input multiple output (MIMO) systems, maximum likelihood (ML) detection can provide good performance, however, exhaustively searching for the ML solution becomes infeasible as the number of antenna and constellation points increases. Thus ML detection is often realized by K-best sphere decoding algorithm. In this paper, two techniques to reduce the complexity of K-best algorithm while remaining an error probability similar to that of the ML detection is proposed. By the proposed K-best with predicted candidates approach, the computation complexity can be reduced. Moreover, the proposed adaptive K-best algorithm provides a means to determine the value K according the received signals. The simulation result shows that the reduction in the complexity of 64-best algorithm ranges from 48% to 85%, whereas the corresponding SNR degradation is maintained within 0.13dB and 1.1dB for a 64-QAM 4 × 4 MIMO system.
{"title":"Low-complexity Prediction Techniques of K-best Sphere Decoding for MIMO Systems","authors":"Hsiu-Chi Chang, Yen-Chin Liao, Hsie-Chia Chang","doi":"10.1109/SIPS.2007.4387515","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387515","url":null,"abstract":"In multiple-input multiple output (MIMO) systems, maximum likelihood (ML) detection can provide good performance, however, exhaustively searching for the ML solution becomes infeasible as the number of antenna and constellation points increases. Thus ML detection is often realized by K-best sphere decoding algorithm. In this paper, two techniques to reduce the complexity of K-best algorithm while remaining an error probability similar to that of the ML detection is proposed. By the proposed K-best with predicted candidates approach, the computation complexity can be reduced. Moreover, the proposed adaptive K-best algorithm provides a means to determine the value K according the received signals. The simulation result shows that the reduction in the complexity of 64-best algorithm ranges from 48% to 85%, whereas the corresponding SNR degradation is maintained within 0.13dB and 1.1dB for a 64-QAM 4 × 4 MIMO system.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"38 1","pages":"45-49"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91177549","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387514
Qingwei Li, Zhongfeng Wang
The sphere decoding algorithm has been used for maximum likelihood detection in MIMO systems, and the K-Best sphere decoding algorithm is proposed for MIMO detections for its fixed complexity and throughput. However, to achieve near-ML performance, the K needs to be sufficiently large, which leads to large computational complexity and power consumption in hardware implementation. In this paper, we have developed some efficient early-pruning schemes, which can eliminate the survival candidates that are unlikely to become ML solution at early stages. Therefore, the computational complexity and the power consumption can be significantly saved. The simulation results show that for the 4×4 64QAM MIMO system, totally 55% computational complexity (or power consumption) can be reduced by applying our proposed schemes.
{"title":"Early-Pruning K-Best Sphere Decoder for MIMO Systems","authors":"Qingwei Li, Zhongfeng Wang","doi":"10.1109/SIPS.2007.4387514","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387514","url":null,"abstract":"The sphere decoding algorithm has been used for maximum likelihood detection in MIMO systems, and the K-Best sphere decoding algorithm is proposed for MIMO detections for its fixed complexity and throughput. However, to achieve near-ML performance, the K needs to be sufficiently large, which leads to large computational complexity and power consumption in hardware implementation. In this paper, we have developed some efficient early-pruning schemes, which can eliminate the survival candidates that are unlikely to become ML solution at early stages. Therefore, the computational complexity and the power consumption can be significantly saved. The simulation results show that for the 4×4 64QAM MIMO system, totally 55% computational complexity (or power consumption) can be reduced by applying our proposed schemes.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"43 1","pages":"40-44"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73558898","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 : 2007-11-21DOI: 10.1109/SIPS.2007.4387620
Hua Yan, Ju Liu
This paper proposes two effective synchronous and parallel recursion schemes to implement regularization super-resolution image reconstruction. In the synchronous recursion, iteration step is adaptively adjusted by the speed of gradient descent to each observation channel. When blur support is too large or low-resolution images are severely degraded, however, the high-frequency information of the desired high-resolution (HR) image is still smoothed. So for fusing the information from different observation channels more effectively, parallel recursion is proposed to reconstruct desired HR image. In the two recursion schemes, spatial integration in down-sampling process is removed as well as system blurs, and nearest interpolation in up-sampling process is used to restrain edge artifact. Simulation results demonstrate that the two proposed implementation schemes give more satisfying results in both objective and subjective measurements.
{"title":"Implementation Schemes of Regularization Super-Resolution Image Reconstruction","authors":"Hua Yan, Ju Liu","doi":"10.1109/SIPS.2007.4387620","DOIUrl":"https://doi.org/10.1109/SIPS.2007.4387620","url":null,"abstract":"This paper proposes two effective synchronous and parallel recursion schemes to implement regularization super-resolution image reconstruction. In the synchronous recursion, iteration step is adaptively adjusted by the speed of gradient descent to each observation channel. When blur support is too large or low-resolution images are severely degraded, however, the high-frequency information of the desired high-resolution (HR) image is still smoothed. So for fusing the information from different observation channels more effectively, parallel recursion is proposed to reconstruct desired HR image. In the two recursion schemes, spatial integration in down-sampling process is removed as well as system blurs, and nearest interpolation in up-sampling process is used to restrain edge artifact. Simulation results demonstrate that the two proposed implementation schemes give more satisfying results in both objective and subjective measurements.","PeriodicalId":93225,"journal":{"name":"Proceedings. IEEE Workshop on Signal Processing Systems (2007-2014)","volume":"16 1","pages":"615-620"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88935320","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}