A communication system comprising: remote units (26a-26i,...), each of the remote units comprising one or more radio frequency units 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; and a controller (22, 24, 60, 80,...) comprising one or more modems or modem functionalities (62, 82, 84,...) and connected to an external network (30,...), at least one of the modems or modem functionalities being a baseband modem or baseband modem functionality and being configured to pass first data corresponding to the information, the at least one of the modems or modem functionalities being configured to perform real-time scheduling of the first data corresponding to the information, wherein the real-time scheduling includes assigning the first data to time and/or frequency resources based on channel state information that is supplied by the mobile devices in downlink scheduling and channel state information that is determined by the controller based on transmissions received from the mobile devices; wherein the controller is separated from the remote units by an intermediate network, the intermediate network comprising a switched Ethernet network (34, 68, 96,...) over which second data corresponding to the information is carried in frames between the controller and the remote units, wherein the controller comprises one or more processing devices, the one or more processing devices being programmed to receive second data from the switched Ethernet network and to process the second data to generate first data, and characterized in that: the one or more processing devices are further programmed to associate one or more additional modems with the one or more of the remote units in response to a change in demand for communication capacity, wherein each of the modems or modem functionalities is configured to perform the real-time scheduling; and wherein the remote units comprise means for performing some baseband modem functions, comprising: for uplink communications, removing a cyclic prefix from time-domain IQ samples in each received OFDM symbol and applying Fast Fourier Transform, FFT, to produce frequency-domain IQ symbols; and for downlink communications, applying inverse FFT, IFFT, and inserting cyclic prefixes. remote units (26a-26i,...), each of the remote units comprising one or more radio frequency units 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; and a controller (22, 24, 60, 80,...) comprising one or more modems or modem functionalities (62, 82, 84,...) and connected to an external network (30,...), at least one of the modems or modem functionalities being a baseband modem or baseband modem functionality and being configured to pass first data corresponding to the information, the at least one of the modems or modem functionalities being configured to perform real-time scheduling of the first data corresponding to the information, wherein the real-time scheduling includes assigning the first data to time and/or frequency resources based on channel state information that is supplied by the mobile devices in downlink scheduling and channel state information that is determined by the controller based on transmissions received from the mobile devices; wherein the controller is separated from the remote units by an intermediate network, the intermediate network comprising a switched Ethernet network (34, 68, 96,...) over which second data corresponding to the information is carried in frames between the controller and the remote units, wherein the controller comprises one or more processing devices, the one or more processing devices being programmed to receive second data from the switched Ethernet network and to process the second data to generate first data, and characterized in that: the one or more processing devices are further programmed to associate one or more additional modems with the one or more of the remote units in response to a change in demand for communication capacity, wherein each of the modems or modem functionalities is configured to perform the real-time scheduling; and wherein the remote units comprise means for performing some baseband modem functions, comprising: for uplink communications, removing a cyclic prefix from time-domain IQ samples in each received OFDM symbol and applying Fast Fourier Transform, FFT, to produce frequency-domain IQ symbols; and for downlink communications, applying inverse FFT, IFFT, and inserting cyclic prefixes. the one or more processing devices are further programmed to associate one or more additional modems with the one or more of the remote units in response to a change in demand for communication capacity, wherein each of the modems or modem functionalities is configured to perform the real-time scheduling; and wherein the remote units comprise means for performing some baseband modem functions, comprising: for uplink communications, removing a cyclic prefix from time-domain IQ samples in each received OFDM symbol and applying Fast Fourier Transform, FFT, to produce frequency-domain IQ symbols; and for downlink communications, applying inverse FFT, IFFT, and inserting cyclic prefixes. for uplink communications, removing a cyclic prefix from time-domain IQ samples in each received OFDM symbol and applying Fast Fourier Transform, FFT, to produce frequency-domain IQ symbols; and for downlink communications, applying inverse FFT, IFFT, and inserting cyclic prefixes.