Methods and arrangements in a radio communications system

US6449290B1 · kind B1 · utility

Assignee

• Telefonaktiebolaget LM Ericsson (Publ) · SE

Inventors

• Per Willars · Stockholm, SE
• Karl Anders Näsman · Solna, SE

Key dates

• Filing date: Jun 12, 1998
• Grant date: Sep 10, 2002
• Expiry date: Jun 12, 2018

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04W56/00
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

Methods and an arrangement for synchronizing communication of framed data via asynchronous base stations (BS1, BS2) in a cellular communication system are presented. The synchronization methods are performed continuously by sending out certain system frame counter states from a central node in the system to all its connected base stations (BS1, BS2). Each base station (BS1, BS2) includes a local frame counter (LFCBS1, LFCBS2), which generates local frame counter states (t1(1)-t1(4), t2(1)-t2(4)) correlated to the system frame counter states. Transmission of information via the base stations (BS1, BS2) is synchronized by assigning each data frame (DR(1)-DR(4)) a particular frame number, which is given by the local frame counter states (t1(1)-t1(4), t2(1)-t2(4)), so that data framed (DF(1)-DF(4)) having identical numbers contain copies of a certain data packet. Correct frame numbers are derived from common downlink channel offset measurements (CCO1, CCO2) carried out in the base stations (BS1, BS2), and timing advance values (TA2) and downlink channel offsets (DCO1, DCO2) calculated in the central node.