Nokia has said it is rejoining the WiMax Forum just a month after the company purposely allowed its membership in the organisation to lapse.

At the company's annual Connections event this week, general manager of its networking business Sari Baldauf told journalists Nokia decided to leave because WiMax had no short-term impact on its plans, but then changed its mind because of heavy involvement in the forum by the rest of the telecoms industry.

"The decision [to leave the group] was perhaps made too much on a practical basis rather than with regard to what the rest of the world is doing," Baldauf said. Some industry observers said the u-turn looked like a move to associate the company with a high-profile technology in order to please investors and analysts, at a time when Nokia was struggling to shore up its handset market share.

The WiMax Forum is the standardisation group pushing the IEEE 802.16 family of wireless broadband technologies. It currently has 105 members including Alcatel, AT&T, BT, Fujitsu and Intel.

Nokia's move is the latest shift in the history of a technology that has consistently made the headlines, despite the fact that the first standardised equipment won't appear until next year. 802.16 and WiMax are an effort to bring a hotch-potch of fixed and mobile wireless broadband efforts together under a single standard, creating the commoditisation and resulting low equipment prices enjoyed by the wireless LAN industry. The first wave of the technology, using the 802.16d and 802.16a standards, will replace the fixed wireless broadband systems that are already in use.

The second wave, more of interest to mobile equipment makers such as Nokia, will use the mobile 802.16e standard. But even WiMax's most vocal backers, such as Intel, say 802.16e equipment won't be around for several years. Nokia said it left the WiMax Forum because the technology simply wasn't relevant to its plans in the near term - though some analysts speculated the company was concerned WiMax would compete with Nokia's 3G efforts.

Other Forum members said lack of interest seemed a more likely motivation. Nokia had next to no involvement in the group beginning just after its foundation, said a spokeswoman for Alvarion, a wireless broadband equipment maker. "Nokia dropped out in substance about a year ago," she said. "The issue came up again now because their membership fee came up for renewal and they just didn’t renew."

Nokia told Techworld that when it left the group the fixed WiMax standards were the only ones being actively developed; since then, more attention has been given to the mobile standard. "There has recently been an initiative to standardise 802.16e, the mobile version. For us that is entirely different," said Oscar Salonaho, head of Nokia's technology marketing.

The addition of high-profile new members to the forum probably did not hurt, according to an analyst. "Having seen this huge group of service providers sign up, including BT and France Telecom, Nokia knew they couldn't ignore this," said Richard Webb of Infonetics Research.

The company's relationship with WiMax has drawn so much attention partly because Nokia was one of the most high-profile founding members of the Forum in the first place; it created the group last April along with Intel, Fujitsu and specialist wireless players such as Alvarion.

The Forum's success is such that equipment maker Navini, which formerly backed the rival 802.20 standard, recently switched camps, while telecommunications heavyweights such as BT, France Telecom and Qwest Communications have also come on board. Alcatel has announced the the first 802.16d equipment using Intel chips, which should appear later this year and be ratified next year.

The WiMax Forum members, chiefly Intel, have gone to great efforts to promote WiMax as the way to standardise both fixed and mobile broadband wireless networks, but the reality is that only fixed systems will be in use in the near future, say industry analysts. As a result, companies interested in using WiMax as a replacement for or complement to fixed technologies, such as DSL, are flocking to join the Forum, while those interested in mobility are keeping their distance.

Nokia has had plenty of other issues to deal with recently. At this week's meeting the company promised to release mid-range and clamshell handsets, the lack of which has been partly responsible for falling market share. The company is in the midst of a controversial campaign to take a controlling stake in smartphone operating system maker Symbian; its deal was approved by German competition authorities this week but other Symbian shareholders may still rebel.

It has also undermined partner RIM's $54 million patent battle this week by paying the company RIM is in dispute with, NTP, to licence its technology so it can release a new smartphone.