Nokia Siemens Networks today named former Nortel president of global services and operations Sue Spradley to head up its North America operations, replacing Mark Louison, who is returning to the Nokia mothership to lead its U.S. handset efforts.

Spradley will set up shop in NSN’s Irving, Texas, headquarters beginning today. As North America region head Spradley is being tasked with growing the company’s sales and operations in the only market where NSN doesn’t enjoy a No. 1 or No. 2 market share since Nokia and Siemens merged their networks business earlier this year.

“Securing a lead position in North America is a strategic goal for Nokia Siemens Networks,” NSN CEO Simon Beresford-Wylie said in a statement. “We are confident that Sue’s dynamic 20-year track record in the telecommunications industry will drive our leadership in this pivotal market.”

Nokia-Siemens focus on the GSM infrastructure market in North America, which takes a backseat to CDMA’s dominance. The combined company not only services the GSM legacy networks of the two Tier I GSM providers, it has built a portion of AT&T’s UMTS/high-speed packet access (HSPA) network—through a Siemens contract—as well as similar network for T-Mobile—through a Nokia contract.

Louison takes over a similarly lagging Nokia handset business. Again only selling to the GSM market, Nokia’s dominant global handset share isn’t reflected in North America where Motorola, Samsung and LG Electronics are the dominant providers of not only CDMA handsets but GSM ones as well. Nokia has been taking steps to rectify that imbalance, by re-entering the CDMA phone space with manufacturing partner and by marketing its high-end lines of Nseries and Eseries smartphones directly to consumers.