Raising cash has become so difficult for Nokia Corp. that the struggling cellphone maker has continued to evaluate its noncore assets for a sale, including its real estate.

Plans to sell Nokia's head office near the Finnish capital Helsinki to real estate investors for €170 million ($220 million) were announced Dec. 4, as the latest move following a year filled with massive layoffs and plant closings.

In August, Espoo, Finland-based Nokia sold Qt, a software technology business, to software firm Digia Oyj (Nasdaq: OMX; Helsinki: DIG1V) for an undisclosed price. And in June, Sweden-based private equity firm EQT announced that it purchased U.K. luxury mobile phone business Vertu Corp. from Nokia.

CFO Timo Ihamuotila expects the deal to wrap up by late December.

Nokia, which has operated out of the building since 1997, has struggled in recent years due to competition from rivals like Apple Inc. (Nasdaq: AAPL), especially in the smartphone market.