Open RAN was, predictably enough, one of the hottest topics of conversation at Mobile World Congress. There were plenty of announcements of products, trials and partnerships from those directly involved in the market, and plenty of commentary from those watching from the sidelines. In the past, the RAN has represented a huge proportion of mobile operator spending, but has been an increasingly closed world to all but a rarefied few vendors. Now, disaggregating and virtualizing the RAN, opening up the interfaces between the elements, and implementing the software on general purpose cloud infrastructure, all provide entry points for new players, whether giants from adjacent cloud and IT worlds, or start-ups in every layer from chips to applications. The operators see…