Fast slewing pseudorandom noise sequence generator and executing method thereof

Abstract

A novel and improved method and apparatus for a fast-slewing pseudorandom noise sequence generator is described. One or more loadable PN generators are controlled by a DSP or microprocessor in conjunction with a free-running counter which maintains a reference offset count. The PN generator will typically be part of a finger or searcher. The DSP or microprocessor may assist in other finger or searcher functions as well as the slew function, and can control one or more fingers and / or searchers. Each PN generator is comprised of a loadable linear feedback shift register (LFSR) or its equivalent, a loadable counter for maintaining an index of the state of that particular PN generator, and a slew control device capable of receiving a slew command and controlling the LFSR and index counter to enact an advance or a retard of a certain offset distance.

Description

technical field

[0001] The present invention relates to communications and, more particularly, to a novel and improved method and apparatus for generating pseudorandom noise (PN) sequences with the capability of rapidly shifting from one bias to another. Background technique

[0002] Pseudorandom noise (PN) sequences are more commonly used in the air interface such as the IS-95 standard and its derivative standards such as IS-95-A and ANSI J-STD-008 issued by the Telecommunications Industry Association (TIA). The direct sequence spread spectrum communication system described in the standard (hereinafter collectively referred to as the IS-95 standard) and is primarily used in cellular telecommunications systems. The IS-95 standard combines Code Division Multiple Access (CDMA) signal modulation techniques to perform multiple communications simultaneously on the same RF bandwidth. When combined with inclusive power control, multiple communications on the same bandwidth, by inc...

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