From February 24 to February 27 our team participated in Mobile World Congress in Barcelona organised by the GSM Association. During the four days over 85,000 visitors from over 200 countries attended the event to see what the 1800 presenting companies had to show.
Our team members Alexander Pyattaev and Adam Surák were presenting the "LTE Assisted Wi-Fi Direct" demo as part of the Intel Corporation exhibition. Thanks to our contributions, a few months ago the technology was added to the LTE Release 12. The live prototype demo helped Intel to promote the idea among the operators and device manufacturers. During the four days of congress, numerous visitors shown interest in the technology, ranging from operators to system integrators of public safety solutions. This gave us a very nice insight into future applications of the technology and new ideas for further research and development.
Cellular operators are currently facing increased congestion levels on their networks due to rapid acceleration in the volumes of mobile data traffic, which translates to poor quality-of-experience (QoE) for the end users. While deploying higher density of serving base stations is indeed expected to mitigate the growing disproportion between the user QoE and the available wireless resources, this solution is costly and hindered by many practical challenges. An attractive simple alternative to relieve cellular network congestion is to enable traffic offloading onto direct device-to-device (D2D) connections in unlicensed bands, as modern multi-radio user devices are already capable of establishing concurrent cellular (HSPA, LTE, etc.) and short-range (e.g., WiFi) links. This demo includes the complete network-assisted D2D technology prototype, which demonstrates reliable cellular traffic offloading onto WiFi Direct links, thus providing seamless D2D connectivity experience. With D2D offloading, the resultant QoE (e.g., video transmission quality) is shown to improve dramatically, even when using bandwidth-hungry and/or real-time mobile applications in challenging urban conditions.
Assume two mobile devices wish to exchange data/set up a P2P connection. Today it is almost impossible with existing cellular and WLAN technologies, and when it is possible, it requires massive manual configuration. On the contrary, in our demo we provide an integrated solution, where application server in the Internet, a D2D (aka ProSe) server in the operator's core network and UE's cooperate to set up the P2P links. In particular, the application server handles the user identity and authorization procedures, D2D server handles the connection management, while the devices are left with the actual content transfer to handle. Such separation of tasks allows each entity to focus on one specific problem, which it can solve efficiently and quickly. For instance, D2D server, through access to cellular Location Services and HSS can quickly estimate if any of the communicating users are close enough for offloading to be enabled.
Should the mobile devices be sufficiently close to each other, the D2D server would notice that and inform them that a D2D connection is feasible (thus executing the networ assisted connection setup), and distribute the one-time keys for it. Should the proximal D2D link be set up successfully, the existing connections between the devices can be seamlessly switched to the new link and back, based on the relative quality of the D2D and cellular links.
You can find more details on the demo flow in the video.
We would like to thank Intel Corporation for the opportunity to present our work, Sony Mobile for providing the cell phones and Ericsson for LTE coverage and technical support at MWC.