New research into the development of 5G networking technology shows that early incarnations are likely to rely on virtual technologies like network virtualization and slicing. Essentially, the early stages of the transition from 4G LTE to 5G look increasingly likely to be done by introducing 5G technologies to 4G connections to increase their speed, capacity, and reliability, while the actual 5G networks, being dependent on entirely new network technologies, are worked on and rolled out. This means that consumers will see leaps and bounds in their wireless speeds, while true 5G will have a bit more time to develop. The 3GPP has stated that the preliminary version of the 5G standard, which gives technologies like these a basic framework with a minimum performance requirement and allows them to be called 5G, will be done by December of 2017.
Network virtualization is essentially exactly what it sounds like. Network enhancements are done offsite using extremely powerful computing and networking equipment, and the resulting capacity and bandwidth are fed to larger-scale local equipment, which is able to use wider spectrum bands than normal to transmit the results. This approach is not ideal for 5G development, but it can produce results far exceeding what current commercial networks have to offer. Network slicing, to put it as simply as possible, delegates different network tasks to different hardware bits, allowing them to use their full capacity and power on a single task rather than running the full networking software stack on a single tower, then transmits the result in a similar way to network virtualization. LTE spectrum expansion techniques like unlicensed LTE band usage, or LTE-U, are sure to play a big part in this development. These technologies are unlikely to simply fall by the wayside once "true" 5G comes about; they will likely be used as a fallback, or simply integrated into the new 5G technologies.
Nokia and other companies are already working on what's being termed 4.9G, which uses traditional LTE networks with new technologies and tweaks, along with replacing certain parts of LTE networking with new equipment and protocols. 4.9G field tests have been going more than well thus far, but what's been seen so far is likely only the beginning. They will turn into what's known as "dependent" 5G, which relies on existing equipment and some existing software, while delivering services with additional hardware, new software-side tweaks, or both. True 5G will use entirely new hardware that mostly utilizes spectrum that's already being used in today's mobile networks, such as T-Mobile's large cache of 600MHz spectrum recently won from the FCC, or the large chunk of 2.5GHz spectrum that Sprint has on hand, which can be used with a small cell setup.