Application of residue number systems to bent-pipe satellite communication systems

Conference Name:2011 6th International ICST Conference on Communications and Networking in China, CHINACOM 2011. Conference Address: Harbin, China. Time:August 17, 2011 - August 19, 2011.ICSTTo reduce the impact on the performance of satellites caused by space radiation environments, redundant structures are introduced into hardware design. Meanwhile, it brings in a new trouble, that is, a great deal of hardware resource is consumed. To overcome the problem, a lot of methods are proposed, one of which is using the residue number system (RNS). The RNS is proved to be suitable to all linear systems in this paper. Since the main modules of Bent-pipe (BP) satellites such as beam forming, finite impulse response (FIR) filters can be approximated to linear systems, RNS becomes an effective way to reduce the area overhead of hardware in BP mode satellite communication systems. ? 2011 IEEE

Sparsity-Based Spatial Interpolation in Wireless Sensor Networks

In wireless sensor networks, due to environmental limitations or bad wireless channel conditions, not all sensor samples can be successfully gathered at the sink. In this paper, we try to recover these missing samples without retransmission. The missing samples estimation problem is mathematically formulated as a 2-D spatial interpolation. Assuming the 2-D sensor data can be sparsely represented by a dictionary, a sparsity-based recovery approach by solving for l1 norm minimization is proposed. It is shown that these missing samples can be reasonably recovered based on the null space property of the dictionary. This property also points out the way to choose an appropriate sparsifying dictionary to further reduce the recovery errors. The simulation results on synthetic and real data demonstrate that the proposed approach can recover the missing data reasonably well and that it outperforms the weighted average interpolation methods when the data change relatively fast or blocks of samples are lost. Besides, there exists a range of missing rates where the proposed approach is robust to missing block sizes

Sparsity-Based Spatial Interpolation in Wireless Sensor Networks

The authors would like to thank Ming-Ting Sun at University of Washington and Zicheng Liu at Microsoft for constructive suggestions.In wireless sensor networks, due to environmental limitations or bad wireless channel conditions, not all sensor samples can be successfully gathered at the sink. In this paper, we try to recover these missing samples without retransmission. The missing samples estimation problem is mathematically formulated as a 2-D spatial interpolation. Assuming the 2-D sensor data can be sparsely represented by a dictionary, a sparsity-based recovery approach by solving for l1 norm minimization is proposed. It is shown that these missing samples can be reasonably recovered based on the null space property of the dictionary. This property also points out the way to choose an appropriate sparsifying dictionary to further reduce the recovery errors. The simulation results on synthetic and real data demonstrate that the proposed approach can recover the missing data reasonably well and that it outperforms the weighted average interpolation methods when the data change relatively fast or blocks of samples are lost. Besides, there exists a range of missing rates where the proposed approach is robust to missing block sizes.Qualcomm-Tsinghua- Xiamen University Joint Research Program;Fellowship of Postgraduates’ Oversea Study Program for Building High-Level Universities from the China Scholarship Council

Prevalence and Characterization of Staphylococcus aureus Isolated From Women and Children in Guangzhou, China

The prevalent Staphylococcus aureus clones and antibiotic susceptibility profiles are known to change dynamically and geographically; however, recent S. aureus strains causing infections in women and children in China have not been characterized. In this study, we analyzed the molecular epidemiology and antimicrobial resistance of S. aureus isolated from patients in four centers for women and children in Guangzhou, China. In total, 131 S. aureus isolates (100 from children and 31 from women) were analyzed by spa typing, multi-locus sequence typing, virulence gene and antimicrobial resistance profiling, staphylococcal chromosomal cassette mec typing, and mutation analyses of rpoB. A total of 58 spa types, 27 sequence types (STs), and 10 clonal complexes (CCs) were identified. While CC59 (ST59-IV, 48.8%; ST338-III, 35.7%) and CC45 (ST45-IV, 100%) were the major clones (84.4%) among MRSA isolates, CC5 (ST188, 24.3%; ST1, 21.6%) and CC398 (ST398, 70%) were the major ones (70.1%) among MSSA isolates. ST338-MRSA-III mostly found in pus but hardly in respiratory tract samples while ST45-MRSA-IV was on the opposite, even though they both found in blood and cerebrospinal fluid sample frequently. Staphylococcal enterotoxin genes seb-seq-sek were strongly associated with ST59 and ST338, while sec was associated with ST45, ST121, ST22, and ST30. All ST338, ST1232, and SCCmec III isolates carried lukF/S-PV genes. A total of 80% of ST338 isolates were resistant to erythromycin, clindamycin, and tetracycline. All ST45 isolates exhibited intermediate or complete resistance to rifampicin. In total, 481 HIS/ASN mutations in rpoB were found in rifampicin-resistant or intermediate-resistant isolates. ST338-III and ST45-IV emerged as two of three major clones in MRSA isolates from women and children in Guangzhou, China, though ST59-MRSA-IV remained the most prevalent MRSA clone. Clonal distribution of S. aureus varied, depending on the specimen source. Virulence genes and antibiograms were closely associated with the clonal lineage. These results clarified the molecular epidemiology of S. aureus from women and children in Guangzhou, China, and provide critical information for the control and treatment of S. aureus infections

Research on Rate Adaptation Used Simulated Annealing Algorithm

Conference Name:International Conference on Mechanical Engineering and Intelligent Systems (ICMEIS 2012). Conference Address: Beijing, PEOPLES R CHINA. Time:AUG 25-26, 2012.This paper analyzes the PHY layer of IEEE 802.11 standards for a variety of transmission rate, after learned that MAC layer does not provide for its adaptive approach. With the study of various adaptive algorithms, the SAARF protocol based on simulated annealing algorithm is proposed on MAC Layer rate adaptation, which can adaptively adjust transmitting rate. Compared with ARF (Auto Rate Fallback) protocol, SAARF can more effectively improve the throughput from the simulation results

A New Efficient Dynamic System Information Scheduling Strategy in TDD-LTE

The TDD-LTE system information which is also necessary to communicate each other well is a kind of important message between user equipment(UE) and eNodeB. Some important parameters are provided by system information to enable the UE to camp on a cell normally and access to common channel. The system information，of course，can provide the mobility management for UE in idle mode.  On the base station side, there are two kinds of scheduling methods of in the TDD-LTE system, and they are fixed scheduling and dynamic scheduling. The MasterInformationBlock (MIB) and the System Information Block Type1 use the fixed scheduling，while the dynamic scheduling is applied to other System Information Blocks (SIB2~SIB13); and these system information are transmitted on the Downlink Shared Channel(DL-SCH). In consideration of using the radio resources reasonably and not affecting other downlink transmitted data，we proposed a dynamic scheduling strategy of system information based on the base station side. DOI: http://dx.doi.org/10.11591/telkomnika.v11i9.330