Shares of Alvarion Ltd. (Nasdaq: ALVR) fell as analysts lowered their 2008 earnings estimates for the provider of WiMAX and wireless broadband network solutions a day after the company announced strong fourth-quarter and year-end results.

Tel Aviv, Israel-based Alvarion announced on Tuesday that revenues for the fourth-quarter ended Dec. 31, 2007, jumped 32% to $66.3 million from $50.3 million a year earlier. Net income moved up to $3.1 million, or $0.05 per share, compared with $2.4 million, or $0.04 per share during the last three months of 2006.

Profit for the entire 2007 doubled to $0.14 per share from $0.07 per share in 2006.

“Alvarion’s 4Q represents a strong finish to the year, but a weak dollar led to high operating expenses and disappointing EPS guidance for 1Q,” wrote analyst Irit Elrad-Jakoby from financial service firm Susquehanna Financial Group in a research note released today.

The company forecasted first-quarter 2008 revenues between $63 million and $67 million, for a profit of between $0.00 per share and $0.03 per share.

“[Alvarion] is exposed to fluctuations in the U.S. dollar exchange rate,” the company said in a statement. “In addition, income is adversely affected by the decrease in interest rates.”

“Lower profitability through 2008 is a disappointing factor since operating leverage is one of the investment positives for 2008,” wrote Jakoby, who is lowering her earnings estimate for the first quarter to $0.02 per share from $0.04 per share. The analyst also lowered her earnings estimate for the entire 2008 year to $0.21 per share from $0.30.

Eric Kainer of ThinkEquity Partners also lowered his earnings estimates, but nevertheless believes Alvarion “is the leading pure play on this global WiMax tsunami, and this is reflected in the company’s very rapid growth rate,” according to his research note.

“We have reassessed our optimism in light of the lower market multiples paid for communications technology companies and overall risk of slower economic performance in parts of the world,” wrote the analyst, who is calling for 2008 earnings of $0.21 per share, compared with a previous guidance of $0.45 per share.

“There are three reasons for our lowered EPS estimates: lower revenue estimates, higher expense estimates, and lower interest income estimates,” he wrote.

Worldwide Interoperability for Microwave Access, or simply WiMAX, is a telecommunications technology for providing wireless data over long distances.

At close, shares of Alvarion Ltd. (ALVR) were down $0.57, or 7%, to $7.23. The 52-week low of $6.95 was set on Jan. 23, while the 52-week high of $15.21 was established on Oct. 2, 2007.