Huawei said its North American research and development efforts will now be headquartered in Santa Clara, Calif. The Chinese vendor's presence in Silicon Valley has expanded from 100 to 600 employees over the past three years. The company, which spent $3.76 billion last year globally on R&D, has its North American headquarters in Plano, Texas, but has been steadily building its footprint in Silicon Valley. Not surprisingly, Silicon Valley is a hotbed of mobile technology development, and Huawei rival Ericsson (NASDAQ:ERIC) also has a large office in Silicon Valley. Article