A method for allocating radio resources by a coordinating wireless communications device in a wireless communications network. The wireless communications network occupies a plurality of narrow-band channels. The method includes: obtaining supported narrow-band channels supported by a wireless communications device joining the wireless communications network, the supported narrow-band channels including a first subset of the narrow-band channels; partitioning the plurality of narrow-band channels into a set of non-overlapping operating channels, each of the non-overlapping operating channels including a second subset of the narrow-band channels; assigning the wireless communications device to an assigned non-overlapping operating channel, wherein the bandwidth of the assigned non-overlapping operating channel is less or equal to the bandwidth of the supported narrow-band channels supported by the wireless communications device; and allocating the radio resources to the wireless communications device, wherein the wireless communications device exchanges data with other wireless communications devices.