By Barry Manz
Even if you are not consumed by wireless technology, it is hard to miss 5G. Naturally, it was the biggest topic at Mobile World Congress earlier this year but has also been covered by major television networks, and in countless influential news vehicles online and in print. Before 4G (LTE) appeared, there was a high level of media attention, as well. However, 5G is at least five years away. Why all the attention?
LTE-Advanced has been drowned out by the noise level from 5G but is nevertheless being deployed, but with far less fanfare than is typical of this industry. There was a time when 3.5G bridged the gap between 3G and 4G, in which passable data rates emerged. Consider LTE-Advanced as 4.5G, a half step between LTE and 5G that increases theoretical data rates and spectral efficiency, handles more concurrent user traffic and delivers better performance at the edges of cell sites’ coverage areas, as well as some other things that help pave the road ahead. It also ushers in carrier aggregation, Multi-Input Multi-Output (MIMO), and relay nodes. Carrier aggregation (Figure 1) battles the carriers’ insatiable addition to bandwidth by combining carriers (channels) at nearby or even very different frequencies to produce greater bandwidth.
MIMO, which you may already know about if you have an IEEE 802.n or IEE 802.11ac Wi-Fi router sprouting multiple antennas, increases data rates by transmitting and receiving two or more data streams on multiple antennas, a technique called spatial multiplexing. Carrier aggregation and MIMO got started with LTE but are enhanced in LTE-Advanced. Finally, LTE-Advanced makes better use of small base stations called small cells that fill in the coverage area. The first LTE-Advanced network was turned on by SK Telecom in South Korea in August 2015 and is being deployed in the United States. Smartphones with LTE-Advanced include Apple’s latest-generation iPhones, most Samsung smartphones, as well as phones from LG, Microsoft/Nokia, Motorola (now Lenovo), Huawei, and Blackberry. Next, get used to hearing 5G called “IMT-2020,” as it was formally named by the International Telecommunication Union (ITU). The ITU is a UN agency that oversees and coordinates worldwide communications. However, most people still call it 5G.