Improved use of network capacity

There is provided a method of improving the use of the capacity of an ultra wideband (UWB) network, the network comprising a plurality of channels the network further comprising a plurality of devices, each device forming a respective beacon group on a first one of the channels, each beacon group including at least one other device in the plurality of devices; the method comprising transmitting data from a first device in a beacon group using a channel other than the first channel whilst a second device in the beacon group transmits data using the first channel. The channels are time frequency code (TFC) channels in a multi band orthogonal frequency division multiplexing (MB-OFDM) system. The invention essentially allows device pairs that would be inactive but awaiting a transmission slot, to switch TFC channels within a superframe and to transmit their data in a slot on another channel which would otherwise be unused.