A mobile telecommunications local area network (20) is described with a concentrator (32) connected to a plurality of radio heads (36, 38) via a local area network (LAN, 20). The concentrator (32) provides remote control of a local timing signal individually in each radio head. The control may be open loop or closed loop and may be provided through the LAN. The concentrator may also provide digital signal processing (DSP) as a shared resource for the radio heads (36, 38). The DSP may include channel coding. The radio heads (36, 38) may provide modulation for channel coded signals transmitted form the concentrator (32) via the LAN (20). The LAN may be wired LAN or a wireless LAN.