Abstract: In a cellular radio system having a two layer cell structure comprised by macrocells (1) overlaying microcells (2), handover occurs only via the macrocell layer. Thus when the quality of a call handled by a microcell (2) deteriorates below predetermined criteria the call is handed up rapidly to the umbrella macrocell and is only handed back down to a microcell when the handset has been in that microcell for a predetermined time and the quality of the link thereto exceeds predefined criteria.

Abstract: In a cellular radio system including a plurality of cells (e.g. cell sectors or micro cells) (4, 5, 8, 9, 10, 11) each normally using a respective channel for interference reduction purposes, a number of the cells are arranged in groups (6) and in the event of a cell associated with equipment moving within a group (6), all cells (4, 5, 8, 9, 10, 11) of that group use a common channel whereby to facilitate handover between them.

Abstract: A multi-mode radio transceiver comprising a sequence of bi-directional circuit modules including a radio frequency input/output amplifier module (1), a radio frequency/baseband I and Q quadrature channel conversion module (2), an analogue/digital conversion module (3), a digital signal processor (4,5), and a digital signal input/output interface (6), with a control means (7) whereby for transmission a radio frequency signal is formed from analogue quadrature I and Q channel components of a digitized signal at baseband and translated to the radio transmission frequency and for reception the radio frequency signals are transformed into I and Q quadrature analogue components at baseband and subsequently digitized.