The Second Workshop on Cognitive Radio Architectures for Broadband (CRAB 2014) will be held in conjunction with the 22nd IEEE International Conference on Network Protocols in Raleigh, North Carolina, October 21-24, 2014. The tentative date for the workshop is Tuesday, October 21, 2014. CRAB 2014 follows the success of CRAB 2013 held in conjunction with ACM MOBICOM 2013. Cognitive radio enables access to broader pools of spectrum and more efficient utilization of current wireless resources and thus plays a key role for the next generation of mobile broadband. Recently, there are more efforts on design and implementation of cognitive radio architecture for broadband applications. Development of novel cognitive network protocols with adaptive configurations is needed to support traffic demands by exploiting all dimensions of wireless spectrum. The traditional static spectrum allocation, although simple, poses a major obstacle for efficient use of limited wireless resources across time, space, and frequency. This challenge has promoted developing cognitive radio technologies for efficient spectrum utilization. There have been efforts to analyze fundamental limits of cognitive radio network capabilities and design algorithms at different layers or cross-layer algorithms to capture spectrum efficient solutions. Beyond these efforts, there is now an increasing demand to develop mature architectures and network protocols for cognitive radios. Novel design paradigms can cover the entire protocol stack and provide spectral agility and resilience with dynamic network protocol functionalities. These capabilities open new ways to improve spectrum efficiency of wireless communications and can be used in many emerging broadband applications, including application of cognitive radio to current 4G LTE environments, and how it could be used to enable 5G or later generations of mobile broadband services.