This increasingly variegated platform drives the requirement for coexistence between 5GNR, LTE and unlicensed technologies – close integration at core and even radio level now, and a harmonized migration path both to 5G and future IEEE 802 standards. The two tracks may not converge entirely but operators are clear that they want the closest possible coexistence so they can mix and match current and future 3GPP and IEEE technologies as their business case requires.
Most work on 5G radio standards is driven by 3GPP, and in the past the IEEE and the Wi-Fi community have been on largely separate, and even competing, paths. However, most stakeholders would welcome convergence between the two, through common interconnectivity frameworks and APIs, if not an actual unified physical layer.
According to the latest WBA annual survey and industry report, 43% of respondents believe that convergence is either crucial or very important to their current network strategy, while 33% say it is important. And looking ahead, 55% say convergence will be crucial or very important, and 29% that it will be important in future network strategies.
This is because a key objective for wireless operators is to increase the flexibility of their networks so they can harness a wide variety of spectrum and equipment resources, to support demanding usage patterns as affordably as possible. Unlicensed spectrum will be an important element of that effort to reduce the cost of wireless capacity. As more unlicensed spectrum is opened up around the world, including in mmWave bands, there will also be a growing number of technologies and use cases which rely on it.
Such developments show how the Wi-Fi platform is evolving, often in parallel with cellular, and sometimes taking the lead in key technology areas like mmWave spectrum. In its latest industry report, the Wireless Broadband Alliance (WBA) says that Wi-Fi will be a key component in three critical 5G use cases – smart cities, IoT sensor networks and safety/surveillance.
The WBA’s CEO Shrikant Shenwai said: “While plans to roll out 5G networks are well on their way, the industry still needs to agree upon the standards for the technology before 2020. The WBA has put together this report to highlight the significant impact that Wi-Fi is having on the definition of 5G.” He added that the WBA was studying what “we as an organization can do to bridge the gap between licensed and unlicensed technologies within this timeframe [to 2020]. The WBA will continue to develop its 5G strategy to work towards ensuring WBA and Wi-Fi networks are ready and enabled to meet the needs of a 5G-based world.”
The IEEE, the standards body for the 802.11 specs which underpin Wi-Fi, has its own 5G Initiative, which falls within its Standards Association (IEEE-SA). This, in turn, is part of the Global Standards Collaboration (GSC), which also includes the ITU plus bodies like ETSI. The IEEE has the advantage of standards activities in many areas of the value chain, in contrast with 3GPP’s narrower focus on the radio and systems architecture/core. The Initiative’s co-chair, Ashutosh Dutta, said: “IEEE 5G is able to build upon IEEE work in several key emerging technology initiatives such as IoT, Smart Cities, Smart Materials, and Brain and Digital Senses. Accessing the technical breadth and depth of IEEE, we will help unlock the potential of the broader 5G ecosystem.”
In the age of blurring lines between licensed, shared and unlicensed spectrum – and the overall race for airwaves – 802.11 may be able to access IMT-2020 identified frequency bands, including exclusive as well as shared spectrum access. Cisco’s Andrew Myles, manager of wireless and security standards, has suggested that the IEEE might take advantage of a 3GPP technology, LTE-LWA (LTE-WLAN Aggregation), part of 3GPP Release 13. This supports aggregation between LTE and Wi-Fi at or just above the PDCP (packet data convergence protocol) layer and so could help 802.11 address any ITU requirements for ‘macro-type’ operations, since these could be satisfied by the cellular partner network (some countries may insist on IMT-2000 compliance for certain use cases).