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 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 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. <EOS>