Control and User Plane Separation of EPC nodes (CUPS) in 3GPP Release-14

One of the items in 3GPP Rel-14 is Control and User Plane Separation of EPC nodes (CUPS). I have made a video explaining this concept that is embedded below.

In 3G networks (just considering PS domain), the SGSN and GGSN handles the control plane that is responsible for signalling as well as the user plane which is responsible for the user data. This is not a very efficient approach for deployment.

You can have networks that have a lot of signalling (remember signaling storm?) due to a lot of smartphone users but not necessarily consuming a lot of data (mainly due to price reasons). On the other hand you can have networks where there is not a lot of signalling but lot of data consumption. An example of this would be lots of data dongles or MiFi devices where users are also consuming a lot of data, because it’s cheap.

To cater for these different scenarios, the control plane and user plane was separated to an extent in the Evolved Packet Core (EPC). MME handles the control plane signalling while S-GW & P-GW handles the user plane

CUPS goes one step further by separating control & user plane from S-GW, P-GW & TDF. TDF is Traffic Detection Function which was introduced together with Sd reference point as means for traffic management in the Release 11. The Sd reference point is used for Deep Packet Inspections (DPI) purposes. TDF also provides the operators with the opportunity to capitalize on analytics for traffic optimization, charging and content manipulation and it works very closely with Policy and charging rules function, PCRF.

As mentioned, CUPS provides the architecture enhancements for the separation of S-GW, P-GW & TDF functionality in the EPC. This enables flexible network deployment and operation, by using either distributed or centralized deployment. It also allows independent scaling between control plane and user plane functions - while not affecting the functionality of the existing nodes subject to this split.

As the 3GPP article mentions, CUPS allows for:

• Reducing Latency on application service, e.g. by selecting User plane nodes which are closer to the RAN or more appropriate for the intended UE usage type without increasing the number of control plane nodes.
• Supporting Increase of Data Traffic, by enabling to add user plane nodes without changing the number of SGW-C, PGW-C and TDF-C in the network.
• Locating and Scaling the CP and UP resources of the EPC nodes independently.
• Independent evolution of the CP and UP functions.
• Enabling Software Defined Networking to deliver user plane data more efficiently.

The following high-level principles were also adopted for the CUPS:

• The CP function terminates the Control Plane protocols: GTP-C, Diameter (Gx, Gy, Gz).
• A CP function can interface multiple UP functions, and a UP function can be shared by multiple CP functions.
• An UE is served by a single SGW-CP but multiple SGW-UPs can be selected for different PDN connections. A user plane data packet may traverse multiple UP functions.
• The CP function controls the processing of the packets in the UP function by provisioning a set of rules in Sx sessions, i.e. Packet Detection Rules for packets inspection, Forwarding Action Rules for packets handling (e.g. forward, duplicate, buffer, drop), Qos Enforcement Rules to enforce QoS policing on the packets, Usage Reporting Rules for measuring the traffic usage.
• All the 3GPP features impacting the UP function (PCC, Charging, Lawful Interception, etc) are supported, while the UP function is designed as much as possible 3GPP agnostic. For example, the UPF is not aware of bearer concept.
• Charging and Usage Monitoring are supported by instructing the UP function to measure and report traffic usage, using Usage Reporting Rule(s). No impact is expected to OFCS, OCS and the PCRF.
• The CP or UP function is responsible for GTP-u F-TEID allocation.
• A legacy SGW, PGW and TDF can be replaced by a split node without effecting connected legacy nodes.

CUPS forms the basis of EPC architecture evolution for Service-Based Architecture for 5G Core Networks. More in another post soon.

A short video on CUPS below, slides available here.



Further reading:

• 3GPP: Control and User Plane Separation of EPC nodes (CUPS)
• ITU: 5G Network Architecture and FMC - Joe Wilke, Ericsson
• Heavy Reading: Service-Based Architecture for 5G Core Networks

5G Patents Progress

More than 23,500 patents have been declared essential to the GSM & 3G as shown in the picture above. I am assuming this includes 4G as well. Anyway, its been a while I looked into this subject. The last time I was looking, 4G patent pools were beginning to form.

For LTE, indeed there is no one-stop shop for licensing. The only company that has tried is VIA Licensing, with their patent pool, but they don’t have licenses for the big players like Ericsson, Qualcomm, Huawei, ZTE, Samsung, etc. The same will probably apply for 5G.

This old picture and article from Telecom TV (link) is an interesting read on this topic.

This official WIPO list shows ZTE, Huawei, and Qualcomm at the top of the list for international patent filers worldwide in 2016 [PDF].

Back in 2015, NGMN alliance was also looking for creation of some kind of patent pool but it probably didn't go anywhere (link)

(Can't recall the source for this one) In March, Ericsson announced plans to license 5G for $5 per device and possibly as low as $2.50 in emerging markets. In November, Qualcomm announced plans to license 5G IP at the same rates established by the NDRC for 4G/LTE phones sold into China: 2.275% for single mode essential patents / 4.0% for the entire portfolio or 3.25% for multimode essential patents / 5.0% for the entire portfolio. All rates are based on the wholesale price of the phone.

Qualcomm also announced that the previously undisclosed $500 price cap will apply to all phones. Qualcomm also announce a rate of less than $5 for 5G for automotive applications and $0.50 for NB-IoT based IoT applications.

Ericsson has filed patent application for its end-to- end 5G technology. Ericsson has incorporated its numerous 5G and related inventions into a complete architecture for the 5G network standard. The patent application filed by the leading telecom vendor combines the work of 130 Ericsson inventors.

Dr. Stefan Parkvall, Principal Researcher at Ericsson, said, “The patent application contains Ericsson’s complementary suite of 5G inventions.” Stefan added, “It contains everything you need to build a complete 5G network. From devices, the overall network architecture, the nodes in the network, methods and algorithms, but also shows how to connect all this together into one fully functioning network. The inventions in this application will have a huge impact on industry and society: they will provide low latency with high performance and capacity.

This will enable new use cases like the Internet of Things, connected factories and self-driving cars.” Ericsson is involved with leading mobile operators across the world for 5G and Pre-5G research and trials. The patent application is likely to further strengthen its position in the 5G race.

More details on E/// 5G patents on their official website here.

Mobile world live has some good details on Qualcomm 5G NR royalty terms.

Smartphone vendors will have to pay as much as $16.25 per device to use Qualcomm’s 5G New Radio (NR) technology under new royalty guidelines released by the company.

Qualcomm said it will implement a royalty rate of 2.275 per cent of the selling price for single-mode 5G handsets and a higher rate of 3.25 per cent for multi-mode smartphones with 3G, 4G and 5G capabilities.

So for a $200 multi-mode device, for instance, Qualcomm noted a vendor would have to pay $6.50 in royalties per device. Royalties are capped at a $500 device value, meaning the maximum amount a smartphone vendor would have to pay would be $16.25 per handset.

The company added it will also offer access to its portfolio of both cellular standard essential patents and non-essential patents at a rate of 4 per cent of the selling price for single-mode devices and 5 per cent for multi-mode devices.

Qualcomm’s rates are notably higher than those announced by Ericsson in March. The Swedish company said it would charge a flat royalty fee of $5 per 5G NR multimode handset, but noted its fee could go as low as $2.50 per device for handsets with low average selling prices.

The official Qualcomm 5G royalty terms [PDF] are available here.

Further reading:

• Ericsson Tries to Avoid Patent War by Publishing Rates for 5G - Bloomberg
• Qualcomm to charge up to $16.25 in royalties for every 5G phone, more than Ericsson’s $5/phone - Fierce Wireless

Thanks to Mike Saji for providing inputs on 4G patent landscape. Thanks to Keith Dyer for interesting tweets on this topic.