PN acquisition and tracking performance in DS/CDMA systems with symbol-length spreading sequences

Braun, W. R.

doi:10.1109/26.650238

Cited by 47 publications

(28 citation statements)

References 5 publications

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“…Therefore, the definition of θ max and (10-13) indicate that N θ max must be an odd integer. Inequality A comparison of this result with (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) indicates that the Kasami sequences are optimal in the sense that θ max has the minimum value for any set of sequences of the same size and period.…”

Section: Sequences With Small Cross-correlationsmentioning

confidence: 99%

“…whereT 11 ,T 12 , andT 22 are the expected values of each T 11 (n), T 12 (m), and T 22 , respectively. Therefore, the mean acquisition time is…”

Section: Serial-search Acquisitionmentioning

confidence: 99%

“…When short spreading sequences are used in a synchronous direct-sequence network, the reduced randomness in the multiple-access interference (Section 10) may cause increased tracking jitter or even an offset in the discriminator characteristic [22]. For orthogonal sequences, the interference is zero when synchronization exists, but becomes large when there is a code-phase error in the local spreading sequence.…”

Section: Code Trackingmentioning

confidence: 99%

“…The update equations of the ACM filter are given by (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) to (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27) and to . The difference between the ACM filter and the Kalman-Bucy filter is the presence of the nonlinear tanh and sech functions in and .…”

Section: Nonlinear Filteringmentioning

confidence: 99%

“…The Gaussian noise emerging from the bandpass filter can be represented in terms of quadrature components as (Appendix C-2) n(t) = n c (t) cos 2πf c t − n s (t) sin 2πf c t (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) where n c (t) and n s (t) have flat power spectral densities, each equal to N 0 over |f | ≤ W /2. Substituting (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22), (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21), and (9-19) into (9)(10)(11)(12)(13)(14)(15)…”

Section: Wideband Radiometermentioning

confidence: 99%

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Direct-Sequence Communication Systems

Torrieri¹

2004

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Approved for public release; distribution unlimited. ii REPORT DOCUMENTATION PAGEForm Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) March 2004 REPORT TYPE ARL-TR-3175 SPONSOR/MONITOR'S ACRONYM(S) 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)U.S. Army Research Laboratory 2800 Powder Mill Road Adelphi, MD 20783-1197 SPONSOR/MONITOR'S REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTES ABSTRACTThis report presents a comprehensive review of the state of the art of direct-sequence communication systems. Although it is largely self-contained mathematically, the report presumes a thorough understanding of modern digital communications. To limit the report to approximately 200 pages, only the most vital aspects of the theory are emphasized, but the cited references provide many details and minor topics. SUBJECT TERMS PrefaceThis report presents a comprehensive review of the state of the art of direct-sequence communication systems. Although it is largely self-contained mathematically, the report presumes a thorough understanding of modern digital communications. To limit the report to approximately 200 pages, only the most vital aspects of the theory are emphasized, but the cited references provide many details and minor topics. Sections 1 and 2 cover the basic definitions and concepts and the fundamental properties of spreading sequences. Sections 3 and 4 derive the symbol error probabilities of coherent systems in the presence of tone or Gaussian interference. Methods of suppressing pulsed interference are analyzed in Section 5. In Section 6, the role of matched filters in direct-sequence systems is examined. Code synchronization, which is the most significant issue in the design of direct-sequence systems, is analyzed in Section 7. Several supplementary methods of rejecting narrowband interference are presented in Section 8. The detection of the existence of a direct-sequence signal by both an ideal receiver and the more practical wideband radiometer are analyzed in Section 9. Section 10 explains and develops the theory of direct-sequence code-division multi...

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Section: Sequences With Small Cross-correlationsmentioning

confidence: 99%

“…whereT 11 ,T 12 , andT 22 are the expected values of each T 11 (n), T 12 (m), and T 22 , respectively. Therefore, the mean acquisition time is…”

Section: Serial-search Acquisitionmentioning

confidence: 99%

Section: Code Trackingmentioning

confidence: 99%

Section: Nonlinear Filteringmentioning

confidence: 99%

Section: Wideband Radiometermentioning

confidence: 99%

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Direct-Sequence Communication Systems

Torrieri¹

2004

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Pseudo‐Noise Code Synchronization of Multicarrier DS‐CDMA Systems on Multipath Fading Channels Part II: Digital Code Tracking with Diversity

Sheen

Chang

1999

Trans Emerging Tel Tech

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Abstract.Pseudo-noise code tracking with diversity reception is investigated for multi-camer direct-sequence code division multiple access (DS-CDMA) systems on multipath Rayleigh fading channels. The traditional noncoherent digital delay locked loop (DDLL) is analyzed under the effects of multipath fading and multiple access interference. A new decision-directed tracking loop based on a differentially-detected phase detector is proposed and analyzed. The new tracking loop significantly outperforms the traditional DDLL. Computer simulations have been conducted to verify our analytical results.

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Code Synchronization

Principles of Spread-Spectrum Communication Systems

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A spread-spectrum receiver must generate a spreading sequence or frequencyhopping pattern that is synchronized with the received sequence or pattern; that is, the corresponding chips or dwell intervals must precisely or nearly coincide. Any misalignment causes the signal amplitude at the demodulator output to fall in accordance with the autocorrelation or partial autocorrelation function. Although the use of precision clocks in both the transmitter and the receiver limit the timing uncertainty in the receiver, clock drifts, range uncertainty, and the Doppler shift may cause synchronization problems. Code synchronization, which is either sequence or pattern synchronization, might be obtained from separately transmitted pilot or timing signals. It may be aided or enabled by feedback signals from the receiver to the transmitter. However, to reduce the cost in power and overhead, most spread-spectrum receivers can acquire code synchronization from the received signal.

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PN acquisition and tracking performance in DS/CDMA systems with symbol-length spreading sequences

Cited by 47 publications

References 5 publications

Direct-Sequence Communication Systems

Direct-Sequence Communication Systems

Pseudo‐Noise Code Synchronization of Multicarrier DS‐CDMA Systems on Multipath Fading Channels Part II: Digital Code Tracking with Diversity

Code Synchronization

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