With telecom service providers now in the fifth year of rolling out 4G networks, the industry is already preparing for what is coming next. Even if it is still very early for consumers to start thinking about 5G, development of any new technology takes a significant amount of time and researchers are currently in the very early stages aligning the key stakeholders as well and setting the vision for future mobile broadband networks.
What is 5G?
Although it is not clear at this point what 5G will be as it has not yet been defined, initial views of some of the big thinkers in the industry suggest the goal with 5G will be to connect everything efficiently and seamlessly with no performance limitations. In other words, just as 5 billion people take mobile voice for granted today, 5G will ensure 50 billion devices have access to high performance mobile broadband throughput, capacity, and latency, regardless of if the connection is accessed in the home, outdoors, or in the office. 5G should guarantee the performance regardless of how many people are on the network and how much data the person or device is consuming.
What will be the focus?
The standard tools available for improving capacity include improving spectral efficiency, spatial efficiency, and using more spectrum. While improving spatial efficiency by the use of small cell radios is often seen as the most efficient method for scaling capacity, early research suggests the amount of spectrum and how it is used will also play a crucial role with 5G networks. In addition to allocating more spectrum bands for future mobile broadband cellular communication networks, regulators are investigating the possibility of sharing spectrum enabling more efficient use of existing resources. Increased use of small cell radios will shrink the cell sizes and enable the use of higher operating frequencies with larger bandwidths. Some researchers are currently testing the propagation characteristics of millimeter wave bands.
Initial feedback from key stakeholders also suggests there will be an increased focus on improving overall utilization and energy consumption. The base station, which consumes the majority of the energy in the network, is expected to shrink in physical size which will drive continued innovation across the RF component ecosystem. Huawei stated in a 5G position paper that the energy-per-bit usage should be reduced by a factor of 1000 compared to today’s networks.
Improving end-to-end latencies five to ten-fold over today’s network would stimulate more innovation and services across a wide range of applications that have not been envisioned yet.
The 5G air-interface is most certainly not settled yet. Some innovators believe 5G will mean a completely redesigned air interface while some view 5G more as the technology that will optimize and combine the performance of existing technologies. It could be the ability to combine a 10 MHz LTE TDD and 40 MHz 802.11ac carrier for DL, while using a 10 MHz LTE FDD or 5 MHz HSPA+ carrier for the UL.
What are the major challenges?
As with any technology transition, there will be a wide range of challenges to overcome. Given that the devices could be combining different technologies and bands, battery consumption particularly in the devices is generally seen as a concern. New innovation will be required to reduce the battery consumption in devices. The use of higher frequencies will also introduce new challenges typically not encountered in the sub-2 GHz range. Huawei also suggested in a 5G paper that new breakthroughs are required for the baseband and RF architecture to meet the computational requirements of new solutions such as mass-scale MIMO (recall the array Samsung engineers prototyped including 64 antenna elements). With the expected proliferation of small cell radios in hyper-dense networks, new innovation will be required to integrate access and backhaul radio products and ensure they can be installed easily using SON technologies. Given that some expect 5G to be able to combine any technology with any spectrum bands, many regulatory hurdles will need to be addressed.
How long before we will see 5G smartphones?
Even if some service providers in Korea and Japan are already including 5G in their roadmaps, it is a bit premature to start forecasting commercial availability of 5G networks and devices, particularly since it is not clear yet what 5G means.
Historically there has been a new mobile technology roughly every 10 years starting with 2G in the early 90s, 3G in the early 2000s, followed by LTE in 2009/2010. If history is any indicator of future performance, 5G devices could be a reality for innovators and early adopters in the 2020 time frame. This of course is just a loose target at this point which will be dependent on too many variables to list here, including how well technologies are adopted across the globe and if the pace of 4G will continue to be adopted at a faster pace than 2G/3G even as we enter the late majority phase.