By John Bahr, CableLabs; Omkar Dharmadhikari, CableLabs; Neeharika Jesukumar, CableLabs; Dhanraj Murali, CableLabs
Seamless connectivity refers to the ability of a device to maintain a stable and uninterrupted internet connection as it transitions between different types of networks, such as Wi-Fi® and cellular networks. In the context of seamless transition while moving between Wi-Fi and cellular, it ensures that the user experiences service continuity without noticeable interruptions or degradation in performance, regardless of changes in network environment.
MNOs (mobile network operators) want to leverage Wi-Fi network deployments to offload the traffic from cellular networks. With the advent of 5G and the use of mmWave frequencies, indoor coverage has become more challenging due to the limited penetration and short range of mmWave signals. Although these issues can be addressed with dense small cell deployments, advanced beamforming, and hybrid network integration, leveraging the widespread Wi-Fi deployments in indoor environments significantly reduces costs. MSOs (multiple systems operator) or MVNOs (mobile virtual network operator) who resell cellular network from MNOs (mobile network operator) want their subscribers to leverage their carrier grade Wi-Fi, community Wi-Fi and home broadband Wi-Fi offerings whenever the Wi-Fi network quality is good enough to meet the service requirements.
Given most of the devices today use a "Wi-Fi First" approach prioritizing Wi-Fi connections over cellular for data transmission when the device can access an available Wi-Fi network, Wi-Fi offload for seamless transition of devices from cellular to Wi-Fi can be achieved. However, because of the "Wi-Fi First" approach, transition from Wi-Fi to cellular causes challenges, where devices stay connected to the Wi-Fi network even when the Wi-Fi network quality is too poor to address the users’ service requirements and a better performing cellular network is available (commonly known as a “sticky-client” issue). Assuming the device can connect to both available Wi-Fi and cellular networks simultaneously, the key challenge is ensuring that the transition between those networks is fast with minimal to no impact on user experience.
The ways in which a device can prioritize between multiple available Wi-Fi networks (carrier grade WiFi, community Wi-Fi, in home Wi-Fi, etc.) have been investigated within Wi-Fi standard bodies.
However, the triggers and thresholds used for initiating a device transition between Wi-Fi and cellularvary across different chipsets, operating systems, OEMs (original equipment manufacturer), and carrier locked devices does not have any defined standards.