Examining the wireless future

As this is the first issue of 2023, it is an appropriate time to look at what our wireless future might hold.

Though WiFi6 has only recently been widely deployed, WiFi7 devices with 320 MHz channels (2x size) will soon be available with the following capabilities: 4K QAM (Quadrature Amplitude Modulation) enabling each signal to more densely embed greater amounts of data compared to the 1K QAM with Wi-Fi 6/6E, and a potential maximum data rate of almost 5.8 Gbps. This is 2.4x faster than the 2.4 Gbps possible with Wi-Fi 6/6E and could easily enable high quality 8K video streaming or reduce a massive 15 GB file download to roughly 25 seconds vs. the one minute it would take with the best legacy WiFi technology.

In addition to WiFi7, the more significant impact to OT and IIoT is the continued development of cellular communications.

Though 5G is still being introduced, discussion is already underway within 3GPP (https://www.3gpp.org/) who develop specifications covering cellular telecommunications technologies, including radio access, core network and service capabilities, which provide a complete system description for mobile telecommunications. Despite the 3G name, this group is responsible for the 4G and 5G standards and have begun work on 6G (expected to become available early in the 2030s) as well as 7G.

In the accompanying table, note that the 3GPP documents define three different services:

• Ultra-reliable low latency communication (URLLS) for real-time data collection
• Enhanced mobile broadband (eMBB) for high data requirements
• Massive machine type communication (mMTC) for “slower” updates (report by exception) in high-density situations       

6G will be designed integrating high-precision localization (with centimeter-level accuracy), sensing (both radar-like and non-radar like) and imaging (at millimeter-level) capabilities, including passive sensing of objects that may not require that they be broadcasting. 

With a targeted increase of 20x bandwidth, 6G makes better use of existing spectrum by expanding the carrier bandwidth from 100 MHz to 400 MHz to provide up to 4x increase in capacity while improvements in antennas through the application of more sophisticated multiple-input multiple-output (MIMO) techniques also make a significant increase in capacity by sending many more streams of data simultaneously. More antenna elements have been added to each successive generation: 4G uses 2x2MIMO and 4x4MIMO, while 5G benefits from massive MIMO using around 200 antenna elements and up to 64 transceivers. 6G may support on the order of 1,024 antenna elements in the new mid-bands.

As implied in the table, 6G will need additional spectrum as well and hence addition of Terahertz radio with new spectrum space as well as integration with non-cellular communications WiFi, satellites, and the ability to accommodate reflective surfaces.

Unlicensed spectrum also has a role to play in dedicated subnetworks, such as private networks or dedicated spectra for specific industries or purposes. To better support IIoT and the real-time requirements for control, future sections of greenfield unlicensed spectra should be allocated to subnetworks, with new regulatory rules tailored to their specific requirements and traffic types while still ensuring fairness among devices. Germany has already done this by dedicating certain spectra to critical infrastructure.

Of course, someone must pay for all the new 6G infrastructure, and providers will want to get return on their 5G investment before implementing 6G.

In a typical mobile network today, CapEx is approximately 30% and OpEx is approximately 70% of the TCO over a 10-year period. The Radio Access Network (RAN) is the biggest cost component in both CapEx (50%) and OpEx (65%), followed by transport, core network, energy, and other network costs (e.g., people, network management and maintenance, etc.). A breakdown of RAN CapEx shows that the largest cost components are site construction, spectrum and equipment. Similarly, a breakdown of RAN OpEx shows that the largest contributors are power consumption, site rentals and operations.

6G has a target to reduce the OpEx by 30% over 5G, which will help with the overall migration return on investment costs.

The future of wireless continues to amaze with is potential. However, this potential also requires careful planning, especially as there is a limit on available spectrum. Part of that planning is to work with regulators to allocate frequencies in each of the URLLS and mMTC ranges as a minimum to support real-time OT requirements.