T-Mobile (NYSE:TMUS) isn't likely to surprise anyone when it reports its fourth-quarter earnings tomorrow, analysts from Barclays and New Street Research said in separate research notes. So investors will likely to be looking for clues about the company's strategy as it prepares for the FCC's upcoming incentive auction of 600 MHz spectrum.

The nation's third-largest mobile operator released preliminary figures last month indicating it would post 4.5 million net adds during the final quarter of 2015, topping estimates of 3.8 million to 4.2 million. And it signaled EBITDA for the fiscal year would come in at the top half of its guidance of $6.8 billion to $7.2 billion, excluding the impact of leasing and its Data Stash program.

Both New Street and Barclays indicated that while carriers are increasingly having to choose between growing their subscriber bases and maximizing revenues, T-Mobile appears well positioned to continue to make progress in both areas, at least in the short term.

Amir Rozwadowski of Barclays noted that T-Mobile's consistent intra-quarter updates reduce the risk of surprises from its earnings calls, adding he expects the carrier will post 1.3 million net postpaid adds, "flattish" sequential churn of 1.46 percent and year-over-year improvement in margins.

"The key metrics to monitor include ARPU (we expect roughly flattish QoQ), pace of the carrier's cash flow inflection (which we expect to improve) and bad debt expense (which we expect to gradually get batter)," Rozwadowski wrote. "While Sprint has extended its '50 percent off' campaign, we do not expect to see a material impact to T-Mobile's porting levels. Tempered promotional activity coupled with the carrier's typical counter seasonal marketing efforts should, therefore, continue to support its share momentum in the near-term."

Analysts at New Street Research agreed. T-Mobile shares are down roughly 10 percent so far this year, New Street Research observed, due in part to concerns that Sprint's aggressive pricing promotions could take a toll and that the possibility of a cable company bidding in the spectrum auction could have an impact on T-Mobile's ability to add to its portfolio of airwaves.

"However, earnings may bring investor focus back to the solid growth profile TMUS offers, diminish(ing) recent concerns regarding price competition from Sprint… while we ultimately believe the participation of Cable in the Auction has favorable implications for TMUS over the intermediate to long-term."

Cable operator Charter Communications recently said it would likely sit the auction out, while Comcast said it will participate but indicated it isn't likely to spend much during the proceedings.

Special Report: Wireless in the fourth quarter of 2015

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