Fixed-Mobile convergence alliance is like when two or more companies join forces to do something together. It's like when two of your friends team up to do a project or help each other out with something. In this case, two or more companies join forces, to share information and resources, so they can make a product that's even better than what they could have done on their own. For example, if two phone companies get together they can share their cell towers and offer customers better coverage - which would be even better than if they had their own separate towers. So, the alliance helps them get more done together than they could on their own.