Certain aspects of the present disclosure provide methods and apparatus for the coexistence of 1 MHz and 2 MHz operation modes within a wireless communication system in accordance with IEEE 802.11ah, for example. One example method generally includes scanning a plurality of channel pairs, wherein each of the channel pairs comprises a first channel having a first channel designation and a second channel having a second channel designation; determining, based on the scan, a set of open channels from the plurality of channel pairs in which no other apparatus is operating; selecting a primary channel based on the determination; and transmitting using the selected primary channel. The selection of the primary channel involves channel selection rules disclosed herein.