Most people in the mobile industry are aware that the Third-Generation Partnership Project (3GPP)—and Global System for Mobile communication (GSM) before it—has traditionally been the lead standards organization in specifying mobile network functionality. 3GPP logically partitions the mobile network architecture into Radio Access Network (RAN), and Core Network (CN) components.

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3GPP will continue to be important in 5G, especially for the RAN-related functionality such as the OFDM and massive MIMO specifications for the radio interfaces. However, knowledgeable observers will also be aware of the fact that a significant number of key 5G protocols will be specified in the Internet Engineering Task Force (IETF). Actually, this is just a continuation and acceleration of trends started way back in 3G.

Looking back at 3G/4G

3G was the generation of mobile technology that first moved away from a circuit-switched voice-centric view of the network. 3G initiated the comprehensive support of packet data to mobile phones albeit at comparatively low data rates. At that time, 3GPP made the strategic decision to start liaisons with the IETF, which was standardizing all of the protocols for the then-emerging premier packet data network, the internet. 3GPP formally agreed to directly use IETF Internet Standards whenever possible, and in all cases avoid duplication of functionality.

More specifically, 3GPP relied on IETF to come up with their key packet data protocols, including the SIP protocol for IMS services, the EAP-SIM protocol for security and the ROHC protocol for compression of IP packets. All of these protocols were specified by the IETF, and then in the language of standards, they were normatively referenced by 3GPP.

This trend accelerated in 4G (LTE) when 3GPP defined the network to be “All IP” and eliminated the circuit-switched voice mode entirely. 4G data rates were also greatly increased to approach land-line DSL connectivity rates. For 4G, 3GPP relied on IETF to standardize even more protocols. Some examples include Proxy-MIP for mobility management and the EAP-AKA protocol for security. Most significantly IPv6 became the specified transport solution for all interfaces in the 3GPP RAN and CN. Thus, the 4G networks became fully integrated sub-networks of the bigger Internet.

Onwards to 5G

The story for 5G is, of course, still being written in 3GPP and IETF, but the requirements are well known and very challenging. As per the trend of the previous generations, 5G will greatly increase the data rates to the users. The target for 5G is a minimum of 100 Mbps to a peak data rate of 10 Gbps.

Also, the RAN latency is targeted for less than 1 msec, which includes edge computing processing time in the RAN. This is often referred to as the Tactile Internet requirement.

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On an architectural level, the requirements are to virtualize the entire RAN and CN infrastructure so that they can be as easy to deploy and scale as data centers and other cloud infrastructure that have revolutionized the IT industry in the last few years. The main difference is that existing IT infrastructure concentrates on storage and compute virtualization. IETF will extend this to also support network virtualization, which has not been previously done in the IT industry.

3GPP, of course, has started to do the critical air interface specifications for OFDM/MIMO. However, 3GPP will rely on the IETF for key specification of virtualization functions. As an aside, the ETSI standards group also has some important specifications for virtualization, but they concentrate on the Management and Orchestration (MANO) aspects and not the actual impacts to the IP network from virtualization. Only IETF has the mandate to change the IP protocols to support network virtualization.

An example of the standardization efforts starting in IETF related to virtualization is the specification of the Service Function Chaining (SFC). SFC will allow dynamically linking of all the virtualized components of the 5G architecture, such as the base station, serving gateway and packet data gateway into one path. This is required because unlike previous generations, 5G processing components—called Virtual Network Functions (VNFs)—will be dynamically created in a cloud-like environment, and so need to be dynamically linked together. In 4G, each of the functions—such as a base station and gateway—were located on a fixed box in the network for which the path was predetermined. However, this 4G architecture was not easily scalable or changeable.

Another area that IETF is looking at is reducing and controlling the delay through the IP network. This is obviously critical to help meet the 1msec latency target of the Tactile Internet requirement. In IETF, this effort is referred to as Deterministic Networking (DETNET) and consists of defining specific IP level properties such as Quality of Service, congestion, etc., and the overall architecture of the IP networks to meet this requirement.

Closing thoughts

Finally, we should not forget that end-user applications will be the commercial driver for 5G as it was for 3G/4G. In 5G, the application may be a virtual reality game running on a mobile phone. Or it may be a streaming HD video application running over each of a thousand security cameras covering a city shopping district. In most cases it is expected that these 5G applications will run over the HTTP protocol as nearly all applications that connect to the internet do today. Here again, IETF is starting important work in improving the HTTP protocol so it runs faster and more securely in mobile environments.

So, in closing, as the 5G hype grows and the debate continues on the various wireless next generation steps, spare some thoughts for the contribution of the IETF. IETF will be critical for many aspects of key 5G functionality from the application level to the network level. As has been the case for several generations now, the IETF will work synergistically with 3GPP to define a fully internet-capable 5G mobile network.