Turning heterogeneous 5G & Wi-Fi networks into a converged network

5G & Wi-Fi: from coexistence to convergence

1.8 Billion 5G smartphones will be sold in the next 5 years generating 12% of total data traffic¹.

As much of the mobile activity is in the home, traffic offload to Wi-Fi is greater than cellular traffic. According to Cisco, the gap will continue to widen due to 5G and should reach 71% of offload².

These figures demonstrate the growing importance of network (5G & Wi-Fi) coexistence. In order to ensure seamless connectivity between these heterogeneous networks, 3GPP has defined in the 5G Release 16 a function called ATSSS that manages 5G & Wi-Fi convergence.

ATSSS stands for Access Traffic Steering, Switching & Splitting. It works as a rules engine where operators’ policies can be specified based on business drivers, technical drivers or a combination of both.

Fig 1- ATSSS capabilities and the benefits for the end-user

3GPP studied more than a dozen different technical solutions to enable 5G and Wi-Fi to coexist efficiently. After one year of discussion, they have decided in December 2018 to leverage the unique capabilities of Multipath TCP combined with the 0-RTT-Convert protocol, defined by Tessares. Multipath TCP enables smartphones to simultaneously use their Wi-Fi and cellular interfaces. Apple has used it since 2013 to improve the experience of mobile users. Samsung, LG and Huawei also use it in some countries to combine Wi-Fi and 4G. The 0-RTT-Convert protocol enables a smartphone that supports Multipath TCP to use its cellular and Wi-Fi interfaces simultaneously through the ATSSS service without increasing latency.

Tessares’ 5G ATSSS

Tessares’ ATSSS solution leverages the experience gained by Tessares in deploying Multipath TCP proxies that support Hybrid Access Networks in different networks that use them to combine xDSL and LTE. Our 5G ATSSS solution is a software package that can be added in virtualised 5G cores.

Fig 2- ATSSS implementation with Multipath TCP architecture

UE stands for User Equipment. 5G access is considered to be 3GPP access contrary to Wi-Fi networks that are seen as non-3GPP access.

5G ATSSS test with KT: A world premiere

Fig. 3- KT 5G ATSSS Gateway – credit photo: KT Group

The first implementation of 5G ATSSS technology in a 5G commercial network was made public on 28 August 2019. KT, formerly Korea Telecom, & Tessares successfully tested a 5G ATSSS service which reduced the initial session setup time to less than half v previous approaches, to achieve 5G ultra-low latency in a multi-radio context (5G & Wi-Fi). Full PR is available here.

If you would like to know more about ATSSS, download our latest white paper describing the central role MPTCP is playing in 5G standardisation.

Contact us at sales@tessares.net for additional information on its features.


(1)– Ericsson Mobility Report (June 2019) – page 7
(2)– Cisco VNI White paper – Forecast 2017-2022