What are Network Functions (NFs) in 5G?

In 5G, the network architecture is changed to ‘Service-based Architecture’ (SBA). SBA allows 5G core solution vendors to move to software-based platform. Hence, eliminating the need to be dependent on proprietary software and hardware vendors. Each software unit in 5G core network is called as the ‘Network Function’. Every NF is entitled to a particular job and acts as a producer as well as consumer for every other NF. The communication is usually done over a software-based stateless interface. Services exposed by these network functions are invoked using a standard API. 5G Core architecture has introduced the concept of CUPS (Control and User Plane Separation).

Architectural diagram of 5G core network functions and interfaces

Following are different Network Functions in 5G and their functionalities:
1. AUSF (Authentication Server Function): Performs the UE authentication. It relies on a backend service for computation and keys. UEs get authenticated only with AUSF in the home network. When the device roams in a serving network a Security Anchor Function acts as the authentication gateway between the serving network and AUSF in the home network.

2. AMF (Access and Mobility Management Function): AMF is a control plane function in 5G core that is solely responsible for registration management, mobility management, reachability management and connection management. It performs registration and de-registration of the UE with 5G core. AMF also performs NAS (Non-Access Stratum) signaling with the UE via gNodeB. Function of AMF is much similar to MME (Mobility Management Entity) from 4G core. It ensures that UE is always reachable.

3. UDM (Unified Data Manager): UDM acts as a centralized repository of the data for authorization, user registration and subscriber profiles. Function of UDM is much similar to HSS (Home Subscriber Server) from 4G. A stateless UDM can store its data in external entity called UDR (Unified Data Repository).

4. PCF (Policy Control Function): PFC maintains the unified policy framework that controls the UE’s behavior with the network. It provides policy rules to other network functions for their enforcement. PCF is similar to PCRF (Policy and Charging Rules Function) from 4G core.

5. UPF (User Plane Function): UPF is the crucial component of the 5G core. It is directly connected to the Data Networks (DN) like internet or IMS. It is responsible for packet routing, packet forwarding, QoS handling and PDU session management. It handles the downlink (DL) and uplink (UL) rate enforcement. It also performs the downlink packet buffering for the UE.

6. NSSF (Network Slice Selection Function): As discussed in the previous post(s) earlier, 5G introduces the concept of ‘network slicing’, where a piece of 5G network is dedicated to a specific use case. NSSF assists AMF with selection of a network slice to serve a particular device. It determines the NS-SAI (Network Slice Selection Assistance Information) for the device.

7. NRF (Network Repository Function): NRF is the key network function in 5G core. It acts as an internal broker for all core network functions. It maintains an updated repository of all network functions along with services provided by them with NF discovery information in an entity called ‘NF Profile’. It allows consumer NFs to discover provider NFs and keep track of other NF instances.

8. NEF (Network Exposure Function): One of the biggest advantages of 5G SBA is that it emphasizes the use of HTTP/2 based stateless APIs for communication. NEF facilitates a third-party application function (AF) by securely exposing some of the services offered by 5G core network functions. It acts as an ‘external broker’ for third-party applications having access to 5G core network information. For example, an external application may try to request information such as UE reachability from AMF. NEF does the job of retrieving this information from AMF and provide it to the external application.

Vietnam’s VinSmart to export its 5G gear

VinSmart, a technology and services arm of Hanoi-based Vietnamese giant VinGroup JSC is looking forward to exporting its 5G-capable devices to western countries. Established two years ago, VinSmart is also first manufacturer of 5G smartphones in Vietnam.

The company has a deal to export 1.5 to 2 million units of its 5G smartphone to the US. While the company is going to focus on its North American presence for the next five years, reports say that it is also planning to bring its 5G equipment in Vietnam’s telecom market in 2021. VinSmart has also tied up with Qualcomm for patent licensing agreements. This connection has also helped it to get an edge over North American market. The company has its portfolio of products in various categories such as, VSmart smartphones, Mi-Fi routers, CPEs, Wi-Fi 6 smart home, routers and 5G laptops.

VinSmart and Qualcomm have been conducting their 5G tests under a lab 5G environment. These tests make sure that the 5G devices are compatible with the global carriers. Last year, Vietnam’s state-run operator, Viettel conducted a 5G network trial and also announced to make its own 5G equipment for the upcoming rollout. We see so many interesting developments around 5G in Vietnam, which could soon become an alternative hub for 5G network gear.

5G just got real – with iPhone 12

Tech giant Apple has finally unveiled it’s most ambitious iPhone lineup till date. This time, the lineup consists of not just 2 or 3, but 4 iPhones, with two base models – iPhone 12 along with a small iPhone 12 mini and two ‘Pro’ models – iPhone 12 Pro and iPhone 12 Pro Max. All iPhone 12 variants support at least sub-6 GHz 5G connectivity. While all these models support mmWave connectivity as well, it will only be exclusive to US versions of the phones, considering lack of usage of the frequency in rest of the world.

Tim Cook making announcement about 5G coming to iPhones

On the spec sheet, all phones have been bumped up with Apple’s latest A14 Bionic chip with better cameras paired with LiDAR sensor on Pro models. LiDAR sensor helps achieve higher level of granularity in AR effects. A14 Bionic chip also makes use of Apple’s 5 nm fabrication process. All phones adopt an all-new squared-off design inspired by iPhone 4S. Base lineup comes in two sizes – 5.4 inch for iPhone 12 mini and 6.1 inch for iPhone 12. Whereas pro lineup comes with 6.1 inch for iPhone 12 Pro and 6.7 inch iPhone 12 Pro Max.

These iPhones can seamlessly switch between 4G and 5G networks based on the usage to conserve battery power. As 5G modems are still new and power-hungry, Apple is trying to avoid overheating issues by switching between 4G and 5G. Apple also demoed 5G download speeds picking up to 4 Gbps in best network conditions and 1 Gbps in typical network conditions. And this is huge!

iPhone 12 Pro and iPhone 12 Pro Max

Apple had skipped going with 5G in last year’s iPhone 11 due to lack of ecosystem and infrastructure. However, things are pretty much different this year and with iPhone 12, 5G has just got real. There has been a lot of talk about 5G going mainstream after this announcement and many operators will probably start kicking off their plans for the network infrastructure. 5G iPhones are definitely going to drive the consumer interest in the next-gen high-speed network.

5G frequencies (sub-6 GHz and mmWave) supported by all iPhone 12 variants (Source: Apple website)

Keeping all the excitement aside, 5G is still in its early days and we do not have sufficient network infrastructure at this point of time except in a few countries and a handful of cities. It will still be few days until these iPhones hit the shelves and reviews are out. There is some skepticism from experts about 5G on new iPhones when it comes to signal reception, battery life and overall performance. But things will be more precise once the reviews are out. While there is no word from Apple about Vo5G or VoNR on iPhone 12, it is safe to consider that an iPhone supporting these standards is still a generation or two away. Also, there is no mention from Apple about any special use cases for 5G. Despite of all this, iPhone 12 is about to bring a necessary ‘push’ for the industry to consider investment in the next-gen network.