An innovative architecture may help a new operator to make headway in a mature mobile market, but it does not guarantee commercial success. In its first quarter, Rakuten recorded a $230m loss on its mobile organization, even though the whole group reported sales of $3.5bn. The company admitted it had had to increase its RAN budget by $2bn after underestimating how many 4G base stations it needed for full coverage of Japan. That error will increase overall capex on the 4G/5G end-to-end network to about $9bn and has already forced Rakuten to raise new funds through a share offering. More concerningly, it has only attracted about 4m mobile customers as of the end of June, in a population of 126m,…