Connecting the unconnected — a “Frugal” 5G design from India to the world
In the modern world, mobile telecommunication is the bedrock for globalisation. Consequently, wireless communication technology has come a long way since the advent of 1st generation (1G) telecommunication networks in the 1980s. The very first 1G cell phone technology with speeds of 2 Kbps, could only provide analog voice call compared to the >1Gbps speeds of the current 5th generation (5G) wireless mobile technology that can support high demand applications like remote surgery and autonomous driving. 5G, besides having speeds several times higher than 4G, promises superior reliability in connections with negligible latency (delay). Although 5G networks have largely been deployed in developed countries, it is notable to mention that even developing countries like India are not far behind. India is scheduled to hold 5G spectrum auctions in July 2022, thereby allotting appropriate 5G frequency bands to telecom carriers and enabling the deployment of 5G infrastructure.
In the last few years, there has been a greater focus on making accessibility and affordability the key cornerstones of the network architecture design, realising the need to connect the “next billion” consumers, primarily in developing countries, to the digital transformation. This is at odds with conventional requirements of high reliability and quality of service. It needs a fundamental rethink of how to appropriately design networks for the new entrants to the telecom revolution. A group of innovative researchers from IIT Bombay, led by Prof. Abhay Karandikar (currently Director of IIT Kanpur), launched the “Frugal 5G” project to address the digital divide across Indian urban and rural populations. The main team members working on this project were Dr. Meghna Khaturia, who recently graduated with a PhD from IIT Bombay under the supervision of Prof. Abhay Karandikar, and Mr. Pranav Jha, a research scientist at IIT Bombay with extensive experience in wireless technology and standardisation. Dr. Khaturia explains, “We tried to understand what the tradeoffs in rural areas are and once we understood those, we exploited them to develop a technology that is actually useful for everyone”.
When asked about the design tradeoffs for a Frugal 5G network, she adds, “Telecom networks in urban areas require 4–5 Gbps speeds and 99.9999% reliability, which is not necessary for connecting remote areas of rural India”. Existing 5G telecom standards, proposed by international bodies such as the third-Generation Partnership Project (3GPP), have such stringent quality-of-service (QoS) requirements, which are not essential for remote rural areas. Dr. Khaturia explains, “Our design focussed on exploiting this flexibility of less stringent QoS requirements; introducing minimal changes to the existing telecom standards to allow for the 5G network to provide acceptable coverage to these users at an affordable cost.”
The researchers identified unique roadblocks specific for rural context after setting up two prototype testbeds in a remote village of Palghar, Maharashtra, based on Frugal 5G architecture. They recognized a need to address issues like low mobility, geographically scattered and clustered settlements, need for low power consumption, affordable maintenance cost, and a high chance of connectivity loss with the main network. In addition, it was necessary to keep the local community satisfied by providing regional content and relevant services. With these above requirements in mind, the researchers set out to investigate where exactly in the whole telecom network architecture key modifications could be done. The ultimate goal was not to develop new technology, but to define an architecture that can leverage existing technology components to enable the rural use case”. This approach reduces the time-to-market drastically as compared to a complete overhaul in design.
Source: M. Khaturia, P. Jha and A. Karandikar, “Connecting the Unconnected: Toward Frugal 5G Network Architecture and Standardization,” in IEEE Communications Standards Magazine, vol. 4, no. 2, pp. 64–71, June 2020, doi: 10.1109/MCOMSTD.001.1900006.
The above diagram shows a simple layout of the proposed Frugal 5G network architecture. The network comprises a macro base station (BS) capable of providing basic connectivity within a radius of 3–4 kilometres. The users residing in village clusters receive high-speed connectivity via Wi-Fi access points (APs). Using a wireless middle mile network, these APs are connected with the optical fibre point of presence (PoP) which connects them to the external network (the core network and the Internet). The network is controlled and managed by a fog node, which is situated at the macro BS.
The researchers brought more intelligence to the fog node which is closer to the end-user, as opposed to the distant core network. The “Frugal 5G” fog node was therefore designed to have some essential network management functionality and distributed storage elements of its own. Essentially, this required the installation of programmable OpenFlow network switches that interface between the user-facing radio-access network (RAN) and the Internet, as well as the core network. This change is minimal and software-based, hence can be achieved easily. Changing the RAN would require a full overhaul of end-user devices, which imposes a high cost and is not acceptable to the needs of the industry such as cell phone manufacturers and telecommunication firms, therefore, it was avoided. The network management utilities ensure that not all communication needs to go through the core network. The distributed storage elements can store regional-specific content, or even host an entire content delivery network (CDN) if there’s enough demand. It can also store a regional database of users. It is now robust to disruptions in connection to the core network and significantly reduces latency for remote areas, improving the quality of service.
When asked about the significance of Frugal 5G from a perspective that the Indian audience doesn’t know yet, Dr. Khaturia emphasised that Frugal 5G is now being actively studied by a dedicated IEEE (Institute of Electrical and Electronics Engineers) working group P-2061 (https://sagroups.ieee.org/frugal5g/) under the Chairmanship of Mr. Pranav Jha. Being at IEEE, Frugal 5G received global attention and valuable feedback from various academia and industry representatives. Moreover, some of the rural connectivity requirements identified by Frugal 5G aligned well with the Low Mobility Large Cell (LMLC) proposal of Telecommunications Standards Development Society, India (TSDSI), which is India’s Standards Development Organisation (SDO), co-founded by Prof. Abhay Karandikar. The standardisation of Frugal 5G in IEEE as global standard IEEE P2061 enables an efficient architecture for deploying in rural areas that can leverage existing radio technology for minimal changes.
The incorporation of academic suggestions into actual standards meets significant pushback from industry typically, because global multinationals have their own vested interests in launching their technology and are well ahead in the RnD cycle. Frugal 5G will go a long way into actually becoming a reality. Since India has a strong legacy of purely academic and theoretical research culture, this requires pushing boundaries that are not typical of Indian academia. Prof. Abhay Karandikar’s group is actively trying to change that perspective led by inspired scholars such as Dr. Meghna. We wish them all the best in their endeavours!
