A communication system comprising: remote units (26a-26i,...) to exchange radio frequency signals with mobile devices (18, 20,...), at least some of the radio frequency signals comprising information destined for, or originating from, a mobile device (18, 20,...); and a controller (22, 24, 60, 80,...) comprising one or more modems (62, 82, 84,...) and connected to an external network (30,...), at least one of the modems (62, 82, 84,...) being a baseband modem (62, 82, 84,...) and being configured to pass first data corresponding to the information; wherein the controller (22, 24, 60, 80,...) is separated from the remote units (26a-26i,...) by an intermediate network (34, 36, 38) over which second data corresponding to the information is carried in frames between the controller (22, 24, 60, 80,...) and the remote units (26a-26i,...), and wherein the second data comprises baseband data, and at least some of the second data comprises baseband data that is compressed in a frequency domain, characterized in that: the intermediate network (34, 36, 38, 68, 96,...) comprises a switched Ethernet network (34, 36, 38, 68, 96,...); at least one of the controller (22, 24, 60, 80,...) and one or more of the remote units (26a-26i,...) is configured to compress the baseband data in the frequency domain for transmission over the switched Ethernet network; and the system is configured so that all the baseband data except for those corresponding to Physical Random Access Channel transmissions from a mobile device (18, 20,...) is compressed in the frequency domain. remote units (26a-26i,...) to exchange radio frequency signals with mobile devices (18, 20,...), at least some of the radio frequency signals comprising information destined for, or originating from, a mobile device (18, 20,...); and a controller (22, 24, 60, 80,...) comprising one or more modems (62, 82, 84,...) and connected to an external network (30,...), at least one of the modems (62, 82, 84,...) being a baseband modem (62, 82, 84,...) and being configured to pass first data corresponding to the information; wherein the controller (22, 24, 60, 80,...) is separated from the remote units (26a-26i,...) by an intermediate network (34, 36, 38) over which second data corresponding to the information is carried in frames between the controller (22, 24, 60, 80,...) and the remote units (26a-26i,...), and wherein the second data comprises baseband data, and at least some of the second data comprises baseband data that is compressed in a frequency domain, characterized in that: the intermediate network (34, 36, 38, 68, 96,...) comprises a switched Ethernet network (34, 36, 38, 68, 96,...); at least one of the controller (22, 24, 60, 80,...) and one or more of the remote units (26a-26i,...) is configured to compress the baseband data in the frequency domain for transmission over the switched Ethernet network; and the system is configured so that all the baseband data except for those corresponding to Physical Random Access Channel transmissions from a mobile device (18, 20,...) is compressed in the frequency domain. the intermediate network (34, 36, 38, 68, 96,...) comprises a switched Ethernet network (34, 36, 38, 68, 96,...); at least one of the controller (22, 24, 60, 80,...) and one or more of the remote units (26a-26i,...) is configured to compress the baseband data in the frequency domain for transmission over the switched Ethernet network; and the system is configured so that all the baseband data except for those corresponding to Physical Random Access Channel transmissions from a mobile device (18, 20,...) is compressed in the frequency domain.