By Eric Auchard and Paul Sandle BARCELONA (Reuters) – The mobile phone industry is now looking to the fast-growing demand for smartphones priced at $100 or below as the market for fancier high-end devices has become saturated, but not all handset makers are able or willing to trade down. Much of the talk this week at the Mobile World Congress in Barcelona, the industrys biggest annual trade fair, has turned from the latest big screen, premium-priced devices to the new, entry-level smartphones that analysts say now overwhelmingly represent the industrys best hope for growth. The ability of top brands like Samsung, Apple and Nokia to differentiate themselves is getting harder, he said. Growth in global smartphone shipments will fall sharply this year and keep slowing through 2018, with average prices dropping significantly as the demand shifts to China and other developing countries, market research firm IDC said earlier on Wednesday.