Aruba wireless should be able to coexist but you need to make sure your design takes in consideration the following:
- Not use the same SSIDs names on both systems
- Make sure the APs are not too close to each other (50 feet or more) , if this is not possible you may need to adjust the power levels
- That either systems are not using rogue containment
- That either systems are using non-overlapping 802.11g channels
- Depending on how dense your AP deployement is you may need to consider just using 20 Mhz channels instead of 40 Mhz for 802.11an