Optus pledges 70pc population cover with new 4G network OPTUS has pledged to reach 70 per cent of the nation's population with its 4G mobile network in the next year as the telco today kicked off a new trial of the superfast service in Canberra. Twelve sites are being trialled across the capital to trial Optus's new 4G variant, known in technological parlance as time-division long-term evolution (TD-LTE) network. TD-LTE has been championed in burgeoning mobile markets in China, Japan and other parts of Asia.