Dynamic spectrum sharing (DSS) is an important enabler of better spectrum efficiency, allowing 4G and 5G to share 4G frequencies on a flexible basis, depending on the device and service in play. This is particularly important for operators like Verizon, which have a shortage of midband 5G spectrum and so could use some of their 4G assets, even before they are ready to switch off LTE. But Verizon rival T-Mobile USA has attacked the technology, saying it is late to market and will be a hog of network resources. On TMO’s earnings call last week, CTO Neville Ray said it would be a “tough year” for DSS, as one of the vendors was “very late” in delivering the technology (that…