(19)

(11)

EP 0 578 801 A1

(12)

(43) Date of publication: 19.01.1994 Bulletin 1994/03 (21) Application number: 93903242.0 (22) Date of filing: 04.02.1993

(51) International Patent Classification (IPC):  H04W 84/ 08( . ) (86) International application number: PCT/GB1993/000235 (87) International publication number: WO 1993/016566 (19.08.1993 Gazette 1993/20)

(84) Designated Contracting States: DE ES FR GB IT SE (30) Priority: 05.02.1992 GB 19920002461 (71) Applicant: GEC-MARCONI LIMITED Stanmore, Middlesex HA7 4LY (GB)	(72) Inventor: HOLLIS, John Nr. Ware Herts SG11 2DD (GB) (74) Representative: Elliott, Frank Edward, et al  GEC Patent Department Waterhouse Lane Chelmsford Essex CM1 2QX Chelmsford Essex CM1 2QX (GB)