Data scrambling system and method and communications system incorporating same

US5917852A · kind A · utility

Assignee

• L-3 COMMUNICATIONS CORPORATION · US

Inventors

• Lee A Butterfield · Jordan, US
• Thomas R. Giallorenzi · Riverton, US
• L Andrew Gibson · Riverton, US
• Dan M. Griffin · Bountiful, US
• Johnny M. Harris · Centerville, US
• Steven B Perkins · Sandy, US
• R William Steagall · North Salt Lake, US

Key dates

• Filing date: Jun 11, 1997
• Grant date: Jun 29, 1999
• Expiry date: Jun 11, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04B1/707
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

Users or subscribers of a multi-user communications system, such as a spread spectrum communications system, provide signals to the central station or base unit of that system, and receive signals therefrom. Avoidance of interference among those users' signals is needed to ensure proper operation of the system. To do so, the data of each user is individually scrambled to randomize the data that different users are transmitting, in order to improve tracking performance at a receiver. The data of each user is scrambled independently, in a manner unique to that user in the system, in order to improve tracking performance and detection performance of a receiver. This scrambling makes the multi-user interference zero mean, and makes it possible to integrate out or average out the multi-user interference. The pattern or sequence used for this scrambling, and the pattern or sequence used for spreading here, are preferably identical except in frequency.