Find the Key to the Backhaul Bottleneck

Given India’s geographic and demographic diversity, we need innovative solutions for backhaul, especially in the context of LTE deployment

India’s mobile penetration, currently at 51%, is projected to reach 72% by 2016, with 367 mn mobile broadband connections. HSPA connections are projected to grow from today’s 10 mn to more than 100 mn by 2014, making India the largest HSPA market worldwide. Bharti airtel has launched LTE services, and the other big players will soon offer 4G services, further fuelling the growth in data services at an unprecedented rate.

Why 3G Failed

While these numbers are encouraging, consumer adoption of 3G services has been poor. The top reasons are dismal speed and poor connectivity. The majority of consumers find little or no difference between the 3G and EDGE or GPRS experience. These are indicative of a backhaul bottleneck, which is usually the case wherever there is an explosion of data. With India’s geographic and demographic diversity, the problem gets more complex and needs innovative solutions.

Earlier, RAN architectures could not support the exponential rise in bandwidth demands. Migration to all IP based packet transport networks is the only viable longterm solution. Within the IP backhaul space, the options are many but with no simple single solution.

Let’s look at some specific geographic and demographic factors. The 3 largest cellular subscriber markets are China, India, and the USA.

What Do the Facts Say?

In India, as the numbers show, the mar- ket is very price sensitive and extremely competitive. In addition, India’s population density has a wide variation from a low of approximately 150 per sq mile in the Andamans to 18,000 per sq mile in Delhi. At an average of 1,000 cell phone users per tower, this translates to roughly 1 tower per 6 sq miles in the Andamans and 18 towers per sq mile in Delhi.

Roughly, the data rates delivered by various cellular technologies are—GPRS115 Kbps, EDGE-236 Kbps, 3G-0.2 Mbps, 3.5G-4 Mbps, and 4G-100 Mbps. With an over subscription ratio of 1:5, this translates to approximately 40 Mbps from each cell tower for 2G and 800 Mbps from each cell tower for 4G. Practically, the subscription ratio for 4G would have to be in the region of 1:3 or 1:2 considering the proliferation of applications and associated online requirements which mean 1.5 Gbps to 2 Gbps from each cell tower. This places a significant demand on the backhaul network.

The diverse geography of India includes large plains, hilly areas, densely inhabited metropolitan cities, smaller towns, rural villages, sparsely populated island states, desert regions, and forested nature reserves which are popular tourist locations, etc. Most of the tourist spots have an influx of subscribers for a few months of the year and a far lower subscriber density otherwise. Since the ARPU changes depending upon the geography and also depending upon the time of the year in some regions, the service providers have a substantial planning challenge.