Frequency auto-correction apparatus for CDMA multipath fading channel

US7095993B2 · kind B2 · utility

Assignee

• The MITT Research Institute of Telecommunication Transmission · CN

Inventors

• Xiaohu You · Nanjing, CN
• Yan Zhang · Palo Alto, US
• Ling Wang · San Ramon, US
• Liangcheng Jiang · 安丰镇, CN
• Shixin Cheng · 林湖乡, CN

Key dates

• Filing date: Dec 12, 2001
• Grant date: Aug 22, 2006
• Expiry date: Dec 29, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04L2027/0055
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

An automatic frequency correction (AFC) apparatus used for CDMA multipath fading channels comprises a frequency-offset evaluator, an automatic frequency correction loop filter and a carrier frequency adjuster. The present invention provides a “multipath energy window” designing method for the non-determinacy of multipath signals in mobile communication environment. Frequency-offset information can be extracted from the multipath energy window by a simple calculation and evaluated by a maximal SNR weight process. This invention also provides a step-variable accumulation adjusting method and greatly improves the response speed of the AFC apparatus as compared with a conventional loop filter, whereby supplies better AFC required for CDMA mobile terminals.