MELBOURNE, Australia-A steady growth in demand for trunked land mobile services (TLMS) has forced the Australian Communications Authority to auction the last two blocks of five channels in Melbourne.
“We’ve come to a situation where demand for trunked land mobile spectrum has exceeded supply,” said the ACA’s Victorian Area Manager Peter Young. “We have a number of applications of genuine need, and we have basically run out of spectrum.”
Young pointed to a gradual build-up of business, with some systems supporting up to 8,000 mobiles, as well as a rising tide of data transmission, though most calls remain voice. In addition, operators have been beginning to upgrade analog systems to digital and thus sought more spectrum to migrate existing services.
“Hopefully in time, when the conversion process is completed, some licenses will be relinquished, which means that we can re-allocate spectrum again,” Young added.
In Australia, TLMS uses single-and two-frequency systems in the VHF mid (70 -87.5 MHz) and high (148-174 MHz) bands; single- and two-frequency systems in the 400 MHz band; as well as 800 MHz trunked systems.
Melbourne’s situation is increasingly reflected in other parts of Australia, Young said, where demand for TLMS spectrum has also been steadily rising. In Sydney, Australia’s largest city, TLMS spectrum was completely allocated “some years ago,” he explained, and operators now commercially negotiate spectrum use. This is likely to happen in Melbourne as well.
Young said in the past five years there has been a steady shift from many users-particularly in service-based industries and government-running their own private mobile radio systems to contracting out to communications operators, such as Telstra and Motorola, to provide TLMS services or to have a fleet of cellular phones.
“Very few companies now operate trunking systems in Australia. The responsibility has been taken over by communications entrepreneurs offering services to customers who could no longer afford to run their service or in particular, maintain the cost of upkeep,” Young said.
Trunking essentially allows many users to share the use of a common pool of radio channels. In Australia, there are about 300 channels nationwide, with about 150 mobiles capable of loading onto each channel at any one time. A typical TMLS system operates within a 100-kilometer radius and can have a single site or multiple sites. A maximum of 20 channels are allowed to operate from a single-site system and 30 from a multiple-site system.
