A new product from Alcatel-Lucent aims to let mobile operators serve more customers using their existing radio spectrum, by offering faster mobile broadband services such as HSPA and LTE on frequencies currently reserved for GSM. Using software-defined radio technology, it will simultaneously support multiple mobile network technologies on one frequency, enabling operators to continue to serve customers with older phones.
There are some non-technological obstacles to adoption of the technology. Particularly in Europe, radio spectrum was in the past licensed for use by a particular technology. Now regulators in several countries are considering allowing operators to roll out other technologies, including HSPA (High-Speed Packet Access) or LTE (Long Term Evolution), on spectrum currently licensed for GSM (Global System for Mobile Communications). One frequency band that is currently undergoing this process, called refarming, is 900MHz.
Delivering HSPA or LTE at 900MHz, which carries further than the higher frequencies generally used for those technologies, would result in better mobile broadband services in rural areas and improved indoor coverage compared to existing services, according to the GSM Association.
To make such changes, operators will need to replace existing radio modules with new ones able to support HSPA or LTE, and here is where Alcatel-Lucent's new Multi-carrier Transceiver (MC-TRX) radio module, which it plans to unveil Thursday, comes in.
A mobile operator can upgrade its base stations with the module, but continue to use the network for GSM in the 900MHz band or 1800MHz band, and then add support for HSPA or LTE when the local regulator permits it, according to Andre Mechaly, vice president for wireless networks strategy at Alcatel-Lucent. Since the module uses a software-defined radio, adding support HSPA only involves changing the software configuration, he said.
To take advantage of the network improvements, users will need compatible modems and mobile phones, but because the module can handle HSPA and GSM simultaneously on the same frequency, those with older phones will still be able to use the old service. Other ways of upgrading the network tend to be all-or-nothing.
Alcatel-Lucent isn't the only vendor working on radio modules that can handle multiple technologies in one frequency band. Its competitors are also working on products, according to Sylvain Fabre, research director at Gartner's Carrier Network Infrastructure group.
Ericsson is waiting for a standard defining how to allow the radio technologies to coexist, and expects to release products in March, Hans Beijner, radio product marketing manager at Ericsson, said via e-mail.
Currently, operators are looking for additional spectrum in which they can offer mobile broadband to more users with better coverage and faster speeds. Refarming their existing spectrum holdings to use faster radio technologies will be an important part of that, according to Fabre.
The pressure is now on regulators to speed up the process, he said.
Some, including those in Finland, France, Malaysia and Tunisia, have already started the process, according to Mechaly. In Sweden, the allocation of the 900MHz band has become a matter for the courts.