Singapore's third largest mobile operator M1 will be investing about $85 million to upgrade its mobile network to improve indoor and outdoor coverage. The investment comes after new 3G service standards kicked in earlier this month that mandates that all indoor areas have to achieve 85 per cent mobile coverage.

Its supplier Nokia Siemens Networks will upgrade M1's core infrastructure to an Internet protocol-based network for dynamic resource allocation. This is tipped to minimize the duration of service outages when certain parts of the network is down. As part of the investment, M1 will also add new radio modules on base stations across the island to enhance both indoor and outdoor coverage.

"Customer experience has always been the key focus for M1. With this latest investment, our customers can look forward to a better mobile experience and coverage," said M1's chief operating officer Patrick Scodeller in a statement on Monday.

M1's network modernisation and deployment of 3G radio network on the 900MHz frequency band are scheduled to complete in the second half of this year.