Spread-spectrum signal acquisition: Methods and technology

A system and method of driect-sequence spread-spec trum TDMA (or TDD) digital communication, wherein acquisition and tracking occurs for a plurality of frames having a predetermined number of time slots. One of the predetermined number of time slots in each frame is assigned for acquisition purposes and carries acquisition and sync digital information. The remaining time slots in each frame have assigned header bytes for tracking purposes. The assigned acquisition time slot is spread with an acquisition direct-sequence spreading code. The remaining time slots are spread with a con munication direct-sequence spreading code. During acquisition, the signal strength in each successive time slot for each spread frame is measured for a given num ber of time frames. The peak is located within the given number of time frames through a major acquistion sweep and a refinement sweep. The major acquisition sweep and refinement acquisition sweep locate the frame and time slot boundaries of the transmitted signal. Once acquired, tracking occurs during the header bytes of each successive remaining time slot. Acquisition, tracking and demodulation of the digital data is per formed with the same circuitry.

[1]  J. Holmes,et al.  Acquisition Time Performance of PN Spread-Spectrum Systems , 1977, IEEE Trans. Commun..

[2]  George L. Turin,et al.  An introduction to digital matched filters , 1976 .

[3]  Ralph Eschenbach,et al.  Applications of Spread Spectrum Radio to Indoor Data Communications , 1982, MILCOM 1982 - IEEE Military Communications Conference - Progress in Spread Spectrum Communications.

[4]  D.A. Gandolfo,et al.  A CMOS/CCD 256-stage programmable transversal filter , 1982, IEEE Journal of Solid-State Circuits.

[5]  D. Schilling,et al.  A Two-Level Coarse Code Acquisition Scheme for Spread Spectrum Radio , 1980, IEEE Trans. Commun..

[6]  R. Ward,et al.  Acquisition of Pseudonoise Signals by Recursion-Aided Sequential Estimation , 1977, IEEE Trans. Commun..

[7]  C. Weber,et al.  Statistical Performance of Single Dwell Serial Synchronization Systems , 1980, IEEE Trans. Commun..

[8]  F. G. Herring,et al.  Low Cost, Miniature, Programmable SAW Matched Filter for Tactical Spread Spectrum Systems , 1983, MILCOM 1983 - IEEE Military Communications Conference.

[9]  G. Sage,et al.  Serial Synchronization of Pseudonoise Systems , 1964 .

[10]  C. Cahn.  Performance of Digital Matched Filter Correlator With Unknown Interference , 1971 .

[11]  R. Ward,et al.  Acquisition of Pseudonoise Signals by Sequential Estimation , 1965 .

[12]  D. Brodtkorb,et al.  Fast Synchronization in a Spread-Spectrum System Based on Acoustoelectric Convolvers , 1978 .

[13]  S.A. Reible,et al.  Acoustoelectric Convolver Technology for Spread-Spectrum Communications , 1981, IEEE Transactions on Sonics and Ultrasonics.

[14]  G.L. Turin,et al.  An introduction to digitial matched filters , 1976, Proceedings of the IEEE.

[15]  D. Grieco.  The Application of Charge-Coupled Devices to Spread-Spectrum Systems , 1980, IEEE Trans. Commun..

[16]  R.W. Brodersen,et al.  Applications of CCD and switched capacitor filter technology , 1979, Proceedings of the IEEE.

[17]  D. Schilling,et al.  Tracking of Frequency Hopped Spread Spectrum Signals in Adverse Environments , 1982 .

[18]  C. Cook,et al.  An introduction to spread spectrum , 1983, IEEE Communications Magazine.

[19]  P. Hopkins.  A Unified Analysis of Pseudonoise Synchronization by Envelope Correlation , 1977, IEEE Trans. Commun..