In a Q&A, Bryan Kim, manager at SK Telecom's Core Network Lab, discusses the mobile operator's heterogeneous network implementation and the service benefits.
SK Telecom has developed an enhanced mobile broadband service that combines two networks: 3G and Wi-Fi or Long Term Evolution (LTE) and Wi-Fi. The mobile operator will launch the 3G/ Wi-Fi heterogeneous network service in the second quarter of 2012 to achieve a maximum data rate of 60 Megabits-per-second (Mbps), while the LTE and Wi-Fi integrated service will be offered in 2013, enabling up to a 100Mbps wireless Internet service.
Q. What exactly has SK Telecom developed?
A. SK Telecom has developed a technology that provides subscribers with a faster data service by using two different wireless networks simultaneously. For instance, customers can enjoy a much faster video streaming service supported by either 3G and Wi-Fi, or LTE and Wi-Fi networks.
To benefit, a handset must use two radio frequencies at the same time. We have also built a system that is installed in the core network for simultaneous transmission.
"If it takes 10s to download a 10MB file using a 3G network and 5s to download the same file using the heterogeneous solution, the impact on the battery life is the same."
Bryan Kim, SK Telecom
Q. LTE-Advanced is standardising heterogeneous networking. This suggests that what SK Telecom has done is pre-standard and proprietary. What have you done that is different to the emerging standard?
A. SK Telecom is not talking about LTE-Advanced technology. This is a technology that enables simultaneous use of heterogeneous wireless networks we’ve deployed.
Q. What are the technical challenges involved in implementing a heterogeneous network?
A. It is technically difficult to realise the technology as it involves using networks with different characteristics in terms of speed and latency. At the same time, the technology is designed to minimise the changes required to the existing networks.
There has not really been challenges when linking the two separate networks but it is always a challenge to analyse the real-time network status to provide fast data services.
Q. What impact will simultaneous heterogeneous network operation have on a smartphone's battery life?
A. Using the heterogeneous network integration solution does increase the battery consumption: the device is using two radio frequencies. However, from a customer's perspective, if it takes 10s to download a 10MB file using a 3G network and 5s to download the same file using the heterogeneous solution, the impact on the battery life is the same.
SK Telecom also plans to apply a scanning algorithm for selecting qualified Wi-Fi networks.
Q. What services can SK Telecom see benefiting from having a 3G/ LTE network combined with a Wi-Fi network?
A. Customers will experience greater convenience when using multimedia services and network games, for example, with increased available bandwidth.
Source: SK Telecom
Heavy users tend to consume a lot of video services through mobile broadband. With this solution, SK Telecom will be providing faster data services to customers compared to when using only one network. This will enhance data service markets. The company has no plans for now to provide services directly.
Q. What mobile services come close to using 60Mbps or 100Mbps?
A. The 60Mbps and 100Mbps are theoretical maximum speeds. People who sign up for a 100Mbps fixed-line network service rarely experience the 100Mbps speed. With this technology, SK Telecom aims to increase the amount of wireless network resources for subscribers by using two different types of networks in a simultaneous manner, which in turn will boost the services that require wider bandwidth including video streaming service and network games.
Q. With a combination of Wi-Fi and cellular, most operators want to get traffic off the cellular network onto the ‘hot spot’. Does SK Telecom really want to fill their cellular network by providing higher speeds?
A. From the customer’s perspective, a Wi-Fi network offers narrow coverage and small capacity and since it is not a managed network, wireless data access is made upon request from customers. Thus, data offloading often does not work as intended by the mobile carriers.
In contrast, cellular networks provide national coverage so if there is an available Wi-Fi network to add to the cellular network, we can simultaneously use the cellular and Wi-Fi networks to offer a data service. By doing so customers will enjoy greater speed data services and mobile operators will be able to naturally offload data.