Brazil’s largest mobile operator by subscribers, Vivo Participacoes, has begun field tests of HSPA+ mobile technology, offering data transmission speeds of up to 21Mbps. Vivo chief executive Roberto Lima declined to provide a timeframe for the commercial launch of the new service, however, citing a lack of backhaul capacity in Brazil as the key obstacle to a swift rollout. The cellco is currently building out its own national backbone and separately, it is also working in partnership with a number of other operators. Vivo’s primary target at this time, Lima said, is to complete the backbone section running from Brasilia to Belem. The project has encountered a number of delays resulting from problems securing permits from state agencies for the cables it is deploying. Vivo is not the only cellco actively moving into the HSPA sphere. Rivals Algar Telecom and TIM Brasil are also said to be exploring using the technology.