If proximity services are to be the next big hope for generating data, and money, from smartphone users, cellular networks will once again have to justify their role in that value chain. Small cells and 3G/4G’s location capabilities make a strong case, based around high levels of security, privacy enforcement and ubiquity. But the unlicensed spectrum options mean a far wider variety of service providers can play, and Bluetooth beacons’ simplicity have made them a popular choice for supporting services from targeted in-store promotions to mobile payments to smart home services. Apple’s iBeacon, the dominant format so far, is just the beginning of the story however, not the end. This week sees Google mounting its challenge to iBeacon, promising to…