A pre-paid wireless telephone plan is one in which users pay into their accounts, which are debited with each use of the service. This contrasts with plans where users are charged a fixed amount monthly for services up to a specified limit.
Unsubsidized here refers not to the telephone service but to the telephone itself. Typically subscribers to a telephone service are constrained to use of specific instruments which are made available to them by the service provider at a substantially reduced price. These instruments are called subsidized, because it appears that the service provider 'subsidizes' the price. Unsubsidized telephones are those which users purchase for themselves on the open market.
Global wireless subscribers are all subscribers to wireless telephone services everywhere in the world. More these 70% of these, says Piecyk, use pre-paid plans and purchase their own phones. Formally, that are unsubsidized pre-paid modifies 70 percent. He identifies these users as a specific group by employing the article the:
... the more than 70 percent of global wireless subscribers that are unsubsidized pre-paid...
We believe a product that addresses these users is necessary in order for Apple to grow its EPS next year.