Blind estimation of direct-sequence spread spectrum m-sequence chip codes

The Massey (1969) algorithm for breaking cryptographic codes based on linear feedback shift register (LFSR) generators can also be used to detect pseudonoise (PN) chip-code sequences in direct-sequence spread spectrum (DS/SS) signals from short intercepted snapshots in low-noise channels. The algorithmic process has been extended in order to estimate DS/SS m-sequence codes of unknown order by solving for the LFSR tap sets over multiple windows using majority-vote logic. The effects on performance of random chip errors, digital modulation, and multiple code schemes, such as code-division (CDMA) and Gold sequences, have been investigated.