Amplitude limitation in CDMA system

US6266320A · kind A · utility

Assignee

• Telefonaktiebolaget LM Ericsson (Publ) · SE

Inventors

• Bo Hedberg · Sollentuna, SE
• Bo Hermansson · Älta, SE
• Christian Nystrom · Sollentuna, SE
• Georg Frank · Nürnberg, DE

Key dates

• Filing date: Apr 8, 1998
• Grant date: Jul 24, 2001
• Expiry date: Apr 8, 2018

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04B2201/70706
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

In a telecommunications network that employs a CDMA scheme, the amplitude associated with each independent CDMA carrier is digitally limited, thereby limiting the peak-to-average power ratio. This, in turn, is accomplished by measuring the instantaneous amplitude for the in-phase and quadrature signals that make up each CDMA carrier, deriving a maximum amplitude based on the instantaneous amplitude measurements, and then deriving one or more scaling factors based, in-part, on maximum amplitude. The one or more scaling factors are then applied to the in-phase and quadrature signals, which are subsequently filtered, combined and modulated by a corresponding CDMA carrier frequency.