LEADER 01773nam 2200421 a 450 001 9910695707903321 005 20070430155948.0 035 $a(CKB)5470000002372706 035 $a(OCoLC)123898756 035 $a(EXLCZ)995470000002372706 100 $a20070430d2007 ua 0 101 0 $aeng 135 $aurmn||||||||| 181 $ctxt$2rdacontent 182 $cc$2rdamedia 183 $acr$2rdacarrier 200 10$aElections$b[electronic resource] $eall levels of government are needed to address electronic voting system challenges : testimony before the Subcommittee on Financial Services and General Government, Committee on Appropriations, House of Representatives /$fstatement of Randolph C. Hite 210 1$a[Washington, D.C.] :$cU.S. Govt. Accountability Office,$d[2007] 215 $a51 pages $cdigital, PDF file 225 1 $aTestimony ;$vGAO-07-576 T 300 $aTitle from title screen (viewed on Apr. 25, 2007). 300 $a"For release ... March 7, 2007." 300 $aPaper version available from: U.S. Govt. Accountability Office, 441 G St., NW, Rm. LM, Washington, D.C. 20548. 320 $aIncludes bibliographical references. 517 $aElections 606 $aElectronic voting 606 $aElectronic voting$xGovernment policy$zUnited States 615 0$aElectronic voting. 615 0$aElectronic voting$xGovernment policy 700 $aHite$b Randolph C$01381215 712 02$aUnited States.$bCongress.$bHouse.$bCommittee on Appropriations.$bSubcommittee on Financial Services and General Government. 712 02$aUnited States.$bGovernment Accountability Office. 801 0$bGPO 801 1$bGPO 906 $aBOOK 912 $a9910695707903321 996 $aElections$93432494 997 $aUNINA LEADER 08358nam 2200673 450 001 9910830557103321 005 20240219134755.0 010 $a1-281-09434-X 010 $a9786611094348 010 $a0-470-17976-7 010 $a0-470-17975-9 024 7 $a10.1002/9780470179765 035 $a(CKB)1000000000376944 035 $a(EBL)319320 035 $a(SSID)ssj0000263682 035 $a(PQKBManifestationID)11256292 035 $a(PQKBTitleCode)TC0000263682 035 $a(PQKBWorkID)10282177 035 $a(PQKB)11493663 035 $a(MiAaPQ)EBC319320 035 $a(CaBNVSL)mat05201539 035 $a(IDAMS)0b0000648104aa0a 035 $a(IEEE)5201539 035 $a(OCoLC)181159465 035 $a(PPN)254517099 035 $a(EXLCZ)991000000000376944 100 $a20151229d2007 uy 101 0 $aeng 135 $aur|n|---||||| 181 $ctxt 182 $cc 183 $acr 200 10$aUltra-wideband communications systems $emultiband OFDM approach /$fW. Pam Siriwongpairat, K.J. Ray Liu 210 1$aHoboken, New Jersey :$cJohn Wiley,$d2007. 210 2$a[Piscataqay, New Jersey] :$cIEEE Xplore,$d[2007] 215 $a1 online resource (249 p.) 225 1 $aWiley series in telecommunications and signal processing 300 $aDescription based upon print version of record. 311 $a0-470-07469-8 320 $aIncludes bibliographical references (p. 217-225) and index. 327 $aList of Figures -- List of Tables -- Preface -- 1. Introduction -- 1.1 Overview of UWB -- 1.2 Advantages of UWB -- 1.3 UWB Applications -- 1.4 UWB Transmission Schemes -- 1.5 Challenges for UWB -- 2. Channel Characteristics -- 2.1 Large-Scale Models -- 2.1.1 Path Loss Models -- 2.1.2 Shadowing -- 2.2 Small-Scale Models -- 2.2.1 Tap-delay line fading model -- 2.2.2 I - K model -- 2.2.3 Saleh-Valenzuela (S-V) model -- 2.2.4 Standard UWB Channel Model -- 3. UWB: Single Band Approaches -- 3.1 Overview of Single Band Approaches -- 3.2 Modulation Techniques -- 3.2.1 Pulse Amplitude Modulation (PAM) -- 3.2.2 On-Off Keying (OOK) -- 3.2.3 Phase Shift Keying (PSK) -- 3.2.4 Pulse Position Modulation (PPM) -- 3.3 Multiple Access Techniques -- 3.3.1 Time-Hopping UWB -- 3.3.2 Direct Sequence UWB -- 3.4 Demodulation Techniques -- 3.4.1 Received Signal Model -- 3.4.2 Correlation Receiver -- 3.4.3 Rake Receiver -- 3.5 MIMO Single Band UWB -- 3.5.1 MIMO Space-Time Coded Systems -- 3.5.2 Space-Time Coded UWB Systems -- 3.6 Performance Analysis -- 3.6.1 TH-BPPM -- 3.6.2 TH-BPSK -- 3.6.3 DS-BPSK -- 3.7 Simulation Results -- 3.8 Chapter Summary -- 4. UWB: Multiband OFDM Approach -- 4.1 Overview of Multiband OFDM Approach -- 4.1.1 Fundamental Concepts -- 4.1.2 Signal Model -- 4.2 IEEE 802.15.3a WPAN Standard Proposal -- 4.2.1 OFDM Parameters -- 4.2.2 Rate-Dependent Parameters -- 4.2.3 Operating Band Frequencies -- 4.2.4 Channelization -- 4.3 Physical Layer Design -- 4.3.1 Scrambler and De-scrambler -- 4.3.2 Convolutional Encoder and Viterbi Decoder -- 4.3.3 Bit Interleaver and De-interleaver -- 4.3.4 Constellation Mapper -- 4.3.5 OFDM Modulation -- 4.4 MAC Layer Design -- 4.4.1 Network Topology -- 4.4.2 Frame Architecture -- 4.4.3 Network Operations -- 4.5 Chapter Summary -- 5. MIMO Multiband OFDM -- 5.1 MIMO-OFDM Communications -- 5.2 MIMO Multiband OFDM System Model -- 5.2.1 Transmitter Description -- 5.2.2 Channel Model -- 5.2.3 Receiver Processing -- 5.3 Performance Analysis -- 5.3.1 Independent Fading. 327 $a5.3.2 Correlated Fading -- 5.4 Simulation Results -- 5.5 Chapter Summary -- 6. Performance Characterization -- 6.1 System Model -- 6.2 Performance Analysis -- 6.2.1 Average PEP Analysis -- 6.2.2 Approximate PEP Formulation -- 6.2.3 Outage Probability -- 6.3 Analysis for MIMO Multiband OFDM Systems -- 6.3.1 MIMO Multiband OFDM System Model -- 6.3.2 Pairwise Error Probability -- 6.3.3 Example: Repetition STF Coding based on Alamouti's Structure -- 6.4 Simulation Results -- 6.5 Chapter Summary -- 7. Performance under Practical Considerations -- 7.1 System Model -- 7.2 Average Signal-to-Noise Ratio -- 7.2.1 Expressions of Fading Term, ICI, and ISI -- 7.2.2 Variances of Fading Term, ICI, and ISI -- 7.2.3 Average Signal-to-Noise Ratio and Performance Degradation -- 7.3 Average Bit Error Rate -- 7.3.1 Overall Spreading Gain of 1 -- 7.3.2 Overall Spreading Gain of 2 -- 7.3.3 Overall Spreading Gain of 4 -- 7.4 Performance Bound -- 7.5 Numerical and Simulation Results -- 7.5.1 Numerical Results -- 7.5.2 Simulation and Numerical Results -- 7.6 Chapter Summary -- Appendix: Derivations of A1, A2, B1, and B2 -- 8. Differential Multiband OFDM -- 8.1 Differential Modulation -- 8.1.1 Single-Antenna Systems -- 8.1.2 MIMO Systems -- 8.2 Differential Scheme for Multiband OFDM Systems -- 8.2.1 System Model -- 8.2.2 Differential Encoding and Transmit Signal Structure -- 8.2.3 Multiband Differential Decoding -- 8.3 Pairwise Error Probability -- 8.4 Simulation Results -- 8.5 Chapter Summary -- 9. Power Controlled Channel Allocation -- 9.1 System Model -- 9.2 Power Controlled Channel Allocation Scheme -- 9.2.1 Generalized SNR for Different Transmission Modes -- 9.2.2 PER and Rate Constraint -- 9.2.3 Problem Formulation -- 9.2.4 Subband Assignment and Power Allocation Algorithm -- 9.2.5 Joint Rate Assignment and Resource Allocation Algorithm -- 9.3 Simulation Results -- 9.3.1 Subband Assignment and Power Allocation -- 9.3.2 Joint Rate Assignment and Resource Allocation -- 9.4 Chapter Summary. 327 $a10. Cooperative UWB Multiband OFDM -- 10.1 Cooperative Communications -- 10.2 System Model -- 10.2.1 Non-Cooperative UWB -- 10.2.2 Cooperative UWB -- 10.3 SER Analysis for Cooperative UWB -- 10.3.1 Cooperative UWB -- 10.3.2 Comparison of Cooperative and Non-Cooperative UWB -- 10.4 Optimum Power Allocation for Cooperative UWB -- 10.4.1 Power Minimization using Cooperative Communications -- 10.4.2 Coverage Enhancement using Cooperative Communications -- 10.5 Improved Cooperative UWB -- 10.6 Simulation Results -- 10.7 Chapter Summary -- References -- Index. 330 $aThe only book that provides full coverage of UWB multiband OFDM technology Ultra-wideband (UWB) has emerged as a technology that offers great promise to satisfy the growing demand for low-cost, high-speed digital networks. The enormous bandwidth available, the potential for high data rates, and the promise for small size and low processing power with reduced implementation cost all present a unique opportunity for UWB to become a widely adopted radio solution for future wireless home networking technology. Ultra-Wideband Communications Systems is the first book to provide comprehensive coverage of the fundamental and advanced issues related to UWB technology, with a particular focus on multiband orthogonal frequency division multiplexing (multiband OFDM). The multiband OFDM approach was a leading method in the IEEE 802.15.3astandard and has recently been standardized by ECMA International. The book also explores several major advanced state-of-the-art technologies to enhance the performance of the standardized multiband OFDM approach. Additional coverage includes: * Characteristics of UWB channels * An overview of UWB single-band and multiband OFDM approaches * MIMO multiband OFDM * Performance characterization * Performance under practical considerations * Differential multiband OFDM * Power-controlled channel allocation * Cooperative UWB multiband OFDM Complete with pointers for future research opportunities to enhance the performance of UWB multiband OFDM technology over current and future wireless networks, this is an indispensable resource for graduate students, engineers, and academic and industrial researchers involved with UWB. 410 0$aWiley series in telecommunications and signal processing. 606 $aOrthogonal frequency division multiplexing 606 $aUltra-wideband devices 615 0$aOrthogonal frequency division multiplexing. 615 0$aUltra-wideband devices. 676 $a621.384 700 $aSiriwongpairat$b W. Pam$f1978-$01646641 701 $aLiu$b K. J. Ray$f1961-$0845671 801 0$bCaBNVSL 801 1$bCaBNVSL 801 2$bCaBNVSL 906 $aBOOK 912 $a9910830557103321 996 $aUltra-wideband communications systems$93993748 997 $aUNINA