"Creating a heterogeneous network is an attractive approach to meeting traffic demands and performance expectations, particularly in situations where traffic is concentrated on hotspots or areas that cannot be suitably covered by the macro layer." Stephen Hire, General Manager, Aeroflex Asia-India

LTE is quickly evolving as the most dominant 4G technology, taking mobile broadband to an unprecedented performance level. To meet expectations and predictions for even higher data rates and traffic capacity beyond what is available in current LTE networks, a densified infrastructure is needed.

Creating a heterogeneous network is an attractive approach to meeting traffic demands and performance expectations, particularly in situations where traffic is concentrated on hotspots or areas that cannot be suitably covered by the macro layer. Heterogeneous network combines big, traditional base stations with small cells and will reduce carriers' reliance on large, macro base stations wherever they need coverage, and will enable mobile operators and end customers alike to increase capacity where needed.

3G/HSPA is already live in India though coverage is still not universal. Similarly, TD-LTE coverage is going to be in selected areas only to start with and later, when LTE FDD is licensed, that too will need time to achieve full coverage. So, network planning is going to require a mix of technologies to balance coverage with reasonable quality of service.

On LTE ecosystem

Verizon Wireless has driven the 700 MHz ecosystem to a high level of maturity though in many markets this band is not available. Apart from 2600 MHz, the other frequency band that is likely to see widespread deployment is 1800 MHz as this allows the re-use of the existing GSM1800 spectrum.

Device manufacturers are developing solutions for all major bands (and some niche bands) so over the coming months one will see a range of user equipment including dongles, smart phones, and tablets that support each of the major bands. Many will also be multimode to facilitate roaming.

On whether 4G makes a big business case

At approximately nine percent of all households, fixed broadband penetration rates are low in India compared to many other countries. Cellular penetration exceeds that of fixed line telephone. Based on this, one should expect that mobile devices will become the most important route to Internet access for most people. Set against that, India also has some of the lowest ARPUs in the world for both fixed and cellular telephony., i.e., the industry faces an interesting situation of huge potential demand but low revenues. Successful business cases need to work out how to balance these.

One part of the solution is to minimize the operational cost. That can in part be done by thorough testing and benchmarking of both networks and devices before launch so that once people start using services, the experience is as smooth as possible.

On test challenges for LTE

With each generation of cellular technology, the physical layer tends to become more sophisticated that drives the need to do additional testing, especially at RF. Test companies such as Aeroflex are working on making the process of testing complex transmission and modulation schemes easier. It is not only the physical layer that is growing more complex but also the signaling that requires specialist network emulators and test mobiles to allow engineers to thoroughly test and debug coding schemes and protocol exchanges - even under fading conditions. Aeroflex has developed innovative solutions to enable both device and network equipment manufacturers to increase their test productivity. In fact, Aeroflex delivered its first LTE test mobile in 2007.