Excuses can't cover your behind forever. At some point, you just have to fess up to real problems.

Three months ago, networking equipment designer Tellabs (Nasdaq: TLAB) said that its customers put some orders on the back burner. While waiting for the delayed business to come back in, the company did a little restructuring to "[align] expenses with revenue."

As it turns out, that wasn't enough -- and the late orders may never drop in. In the just-announced fourth-quarter report, Tellabs unveiled another, much larger and deeper restructuring that will slash 530 heads off the payroll. And the motivation is still the same: "In a climate of economic uncertainty, Tellabs needs to align expenses with revenue," said CEO Rob Pullen.

Third-quarter sales came in at $317 million, a 23% year-over-year drop but right in the middle of official guidance. Non-GAAP earnings per share just squeaked into positive territory at $0.01, about half of the year-ago result. Next quarter, management will ask you to look the other way as a $107 million restructuring charge rears its ugly head.

As part of the cost-cutting effort, Tellabs will also stop developing an LTE version of its high-end mobile routing product. The company will continue to support the WiMax version of the same 4G router, but don't expect any big orders there. LTE appears to have won the 4G wars, particularly in the important North American market.

This report confirms what rival Juniper Networks (Nasdaq: JNPR) tells us about slow network investments by American telecom giants. Like Juniper, Tellabs counts AT&T (NYSE: T) and Verizon (NYSE: VZ) among its largest customers.

If Juniper was rising while Tellabs fell, or the other way around, we could draw conclusions about shifting market shares. Instead, this two-part news is solid evidence that network installations have become a low priority. I don't think that jells with the supposed spectrum shortages. Sure, both Ma Bell and Big Red have already rolled out large chunks of their next-generation LTE networks, but there's still a lot of work left to do. Have you seen how spotty Verizon's 4G coverage map is today? AT&T doesn't even bother marking 4G connections on its own maps.

Tellabs shares fell nearly 8% on the news and have basically gone nowhere since last summer. I'd call this a buying opportunity if not for the faint whiff of desperation I smell in the ongoing restructuring efforts.

If you're looking for a stock in the mobile space that Foolish analysts love right now, take a peek at a few semiconductor stocks with tremendous prospects in 2012 before it's too late. This report won't be free forever.