Methods and apparatus for receiving n-chip resistant codes

Abstract

The invention relates to systems and methods for receiving signals modulated with a carrier frequency, wherein the signals include spreading chip sequences having at least one zero. The invention includes a method of receiving and despreading spread spectrum signals wherein the spread spectrum signals include spreading chip sequences having at least one zero and at least one non-zero chip. The method includes receiving and sampling a spread spectrum communication signal. The receiver generates a despreading code which is synchronized with the sampled spread spectrum communication signal. The sampled spread spectrum communication signal is then despread with the despreading code by omitting at least one operation involving at least one zero chip. The invention further includes a receiver configured to receive signals modulated with a carrier frequency over a channel, wherein the signals include spreading chip sequences having at least one zero. The receiver includes an antenna capable of receiving a spread spectrum communication signal. It also includes a despreading code generator connected to the antenna. The receiver includes a demodulator connected to the antenna and configured to separate the carrier frequency from the spread spectrum communication signal. It also includes a searcher connected to the demodulator and configured to synchronize a despreading code generated by the despreading code generator with the spread spectrum communication signal. The receiver also includes a Rake receiver connected to the demodulator, configured to despread the separated spread spectrum communication signal and to omit at least one operation involving at least one zero chip.