The worldwide market for mobile WiMax services in 2015 will be five times its current size, according to ABI Research - but smaller than the company's analysts had expected just a few months ago.

On Thursday, ABI said it had scaled back its forecast of mobile WiMax users by about 15 percent since Russian service provider Yota announced in May that it would start deploying LTE (Long-Term Evolution). A majority of mobile operators around the world that plan to offer 4G (fourth-generation) mobile data have said they will use LTE instead of WiMax.

ABI now expects 59 million people around the world to be using mobile WiMax services by 2015, according to analyst Xavier Ortiz. In May, the company had issued a prediction for 2014, and by way of comparison, its new forecast shows about 15 percent fewer WiMax users in 2014, Ortiz said. ABI expects 12 million people to be using mobile WiMax by the end of this year.

Yota had been one of the biggest service providers committed to WiMax and logged rapid subscriber growth with that technology, Ortiz said. When Yota announced its LTE plan, it cited brighter prospects for a wide selection of client devices built for the new technology. Yota said it planned to roll out LTE in five cities in Russia this year.

Only a handful of LTE networks have launched commercially, but the GSM (Global System for Mobile Communications) Association said in June that there were 80 firm deployments taking place in 33 countries and another 30 networks in the planning stages.

Even Clearwire, which is building a WiMax network across the US, now plans to carry out trials of LTE. The carrier has so much spectrum that it could deploy both types of networks side by side in many markets. Sprint Nextel, the majority owner of Clearwire and a major wholesale provider of its WiMax services, has said it is firmly committed to WiMax.

WiMax carrier migrations to LTE aren't likely to disrupt services for subscribers, Ortiz said. Makers of silicon for WiMax devices already are working on chips for dual-mode clients that could use either type of network, and any existing WiMax infrastructure will probably remain up and running for several years, analysts say.