Leading Estonian operator Tele2 took an unconventional approach to expanding its 4G network to meet growing demand. Rather than rolling out LTE at 2.6 GHz, Tele2 refarmed some of its 2.1 GHz spectrum used for 3G. Nokia developed new software to run 3G and 4G as part of a Single RAN solution. The groundbreaking project resulted in an approximately 41 percent reduction in carbon emissions compared to a conventional network at the higher frequency.