In early December, I attended the 3GPP RAN#74 TSG meeting in Vienna, Austria. This was the last plenary meeting before the official 5G work item (WI) kicks off at the 5G RAN #75 meeting in Dubrovnik, Croatia in March. The 3GPP membership has poured a lot of investment into the study of new technologies and methods to meet the 5G architecture requirements, and with the first big milestone just three short months away, here are a few high level takeaways from the 3GPP Workshop covering 5G.
First, many companies continue to push their concepts and technologies for inclusion into the first WI. However, time is running out. In March, the 5G Phase 1 WI will start and serve as the base for the initial 5G specification (3GPP Release 15). Although the 3GPP is planning for Phase 2 to start 18 months after Phase 1, use cases or technologies not included in Phase 1 must wait an additional 18 months, which could be commercially challenging for some.
On the opposite side, the 3GPP leadership proposed narrowing the scope of some of the work in Phase 1 to increase the probability of meeting the March deadline and ultimately the Sept 2018 finalization goal. Although no consensus was reached in Vienna, it is clear something has to give in order to move forward. With time the ultimate equalizer, innovation may need to be tempered with the reality that the study items must be completed and consensus reached before the definition phase can begin.
In parallel, the 3GPP continues to evolve LTE 4G particularly for the IoT (NB-IoT), MTC (LTE-MTC), and V2X use cases. In fact, some have proposed delaying 5G work related to these use cases to assess whether these new LTE evolved technologies can address the IMT-2020 requirements. The 3GPP has already signaled that a primary use case for Phase 1 will be eMBB (enhanced Mobile Broadband), and this may be the major achievement of the Phase 1 work.
Also of interest, eMBB is looking more like a mmWave or cmWave system utilizing multi-carrier OFDM and up to 8 component carriers with a minimum of 100 MHz of bandwidth. Consensus was reached on channel coding with LDPC proposed for data and polar coding targeted for the control channels. Requiring two coding methods is curious because this requires a mobile device to include both methods in the physical layer with the mobile switching between the two depending on the state of the link - increasing cost and adding complexity. Although each method has its merits, it will be interesting to see if the current status quo goes unchecked in March.
Finally, the 3GPP came to consensus on 5G terminology. The new 5G physical layer will be officially named, “NR” for new radio. The new 5G core network will be called, “5G CN”. A connection between NR and 5G CN will be named “NG”. (I think it is safe to say that the marketing experts were conspicuously absent from this discussion.) On to Dubrovnik!