Making mobile data downloads swifter

Figure 1. Caching of content at the edge (Base stations, Access points, etc.) of a heterogeneous cellular network

We’re hoping that Lalhruaizela Chhangte completes his research quickly, for his work promises to make mobile data downloads swifter and more efficient!

“Global mobile data traffic is expected to increase nearly eightfold between 2015 and 2020; unfortunately this means network congestion will increase too. One way to effectively reduce congestion in the backhaul links of today’s IP networks is caching videos and non-voice traffic closer to mobile and wireless devices,” says this research scholar with the IITB-Monash Research Academy. “That’s what motivated me to work on my project: A Software-Defined Testbed For Real Time Network Simulation.”


Video is the major component of IP traffic over mobile and wireless networks. Already, it constitutes more than half the mobile and wireless data traffic. Unlike voice traffic, though, video is more predictable and delay-tolerant.

“The popularity of videos can be estimated by tracking user activity, and this can be used to identify the contents in demand,” says Lalhruaizela. “Wireless technology has dominated access networks with WiFi Access Points (APs) at the last hop. More than a billion APs were shipped in the last decade and this number is expected to increase. The latest WiFi APs either come equipped with storage capacity or have the option to add it on. This makes them capable of storing considerable amount of contents. With storage becoming cheaper and WiFi APs present abundantly in homes and workplaces, a natural proposition would be to use these devices to cache contents and serve users’ requests locally from the access point’s caches. This should help reduce the frequency of fetching contents from remote content servers, and thus mitigate congestion in the backhaul links,” he smiles. Backhaul refers to intermediate links between the core network and smaller subnetworks.

Figure 2. High level design of the SDN based caching system using APs

Lalhruaizela is working on the design and implementation of a distributed content caching system in WLAN which uses storage in low-cost wireless APs to cache and deliver contents to mobile clients. “Technically speaking,” he says, “we have designed and implemented a software defined networking (SDN) based distributed caching system over wireless APs, which minimises the need to fetch content from remote content servers. It also addresses two major WLAN challenges during content delivery—client mobility and load balancing on WiFi APs.”

Figure 3. Flow of control and data in the system as a user requests a content

The IITB-Monash Research Academy is a collaboration between India and Australia that endeavours to strengthen scientific relationships between the two countries. Graduate research scholars like Lalhruaizela study for a dually-badged PhD from both IIT Bombay and Monash University, spending time at both institutions to enrich their research experience.

The applications for this work are many.

Service providers that have deployed thousands of wireless access points in public places such as coffee shops, shopping malls, airports, train stations, and sports stadiums can use the idea proposed to cache contents (videos, music etc.) which are in high demand in the APs to provide faster and seamless content downloads to users.

Also, educational institutions, which deploy hundreds of wireless access points in campus buildings and hostels will hopefully be able to cache content that is frequently accessed or downloaded in the APs. This will reduce the data consumption from third party Internet service providers, and also utilise the existing storage capabilities of the wireless APs.

Says Prof Murali Sastry, CEO of the IITB-Monash Research Academy, “Due to the huge data explosion over the Internet, and the ever-increasing demand for data from users, efficient and reliable caching has become vital. At the Academy, we will certainly track Lalhruaizela’s progress closely.”

We suggest you do too!

Research scholar: Lalhruaizela Chhangte , IITB-Monash Research Academy

Project title: A software-defined testbed for real time network simulation

Supervisors: Prof. Nikhil Karamchandani, Prof. D Manjunath, Prof. Emanuele Viterbo

Contact details:

The above story was written by Mr Krishna Warrier based on inputs from the research student, his supervisors, and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy