RF transmission tech heads towards unprecedented growth

Jörg Springer, VP of global marketing and communications at RFS

The wireless communications sector has a myriad of exciting frontiers, seemingly spawning new technical advances in the blink of an eye.

By contrast, coaxial RF (radio frequency) transmission line, at least at first glance--appears to be static and decidedly "˜unsexy.'

Yet, significant changes occurring in today's wireless industry and global commodities markets are seeing this "˜plain Jane' of the wireless sector blossom into important new variants.

The reasons behind this change are many.

Among these are the end-to-end network performance pressure associated with 3G and 3.5G broadband wireless data technologies, and the increasing demand to reduce network capex and opex.

With every element in the cellular link under performance and cost scrutiny, the RF transmission line--one of the final links between the base station and the air interface--has had to evolve into new forms to shoulder the burden.

Coaxial transmission line provides the crucial RF link between the base transmitter station (BTS) or Node B and the antenna at the tower top.

Typically spanning 20 to 50 meters, it represents the wireless network's final hardware link before embarking on the cellular air interface.

There are a number of interesting facts regarding this final link. While the cost of coaxial transmission line is typically between one and two per cent of the total tower/base station capex, the total wireless market demand is well in excess of one hundred million meters of transmission line per year.

Added to this are transmission line maintenance costs. Transmission line failures can occur, largely due to poor installation or use of less than premium-quality components.

What has really tipped the balance in the transmission line equation is the performance demands of broadband wireless data technologies such as WiMAX, HSDPA/HSUPA, MBMS, 3G/LTE and FLARION.

This is spawning an entirely new selection of what is known as "˜premium attenuation' transmission line variants--coaxial cable that strips dB losses from the "˜final link', and adds this to dB performance at the tower top. How manufacturers are achieving this varies quite widely, but the end-goal, at least from an RF performance perspective, is largely the same, to realize reduced transmission line losses and maximize the area of highest data rate reception surrounding the base station. 

Another important factor is the changing nature of the global wireless market, coupled with the volatile nature of global commodity prices.


On the one hand, we've seen wireless technology quickly evolve from one that is exclusively the domain of wealthy countries, to one that is providing a means of "˜leap frogging' communication evolutionary stages.

In many parts of Africa, India, China and across the more remote parts of Russia, wireless penetration now far outstrips wired connections.

Per point, it is often far less costly to deploy, and most importantly, faster--particularly where wired backbone and exchange infrastructure might be at an early stage of development. 

Yet the global increase in raw material costs--notably copper and oil-based products--impedes such wireless "˜leap frog' strategies, particularly in those countries where average revenue per unit (ARPU) figures are low and margins tight.