Palen, L., and Salzman, M. (2001). Welcome to the wireless world: problems using and understanding mobile telephony. In Harper R. and Brown B. (eds.) The Wireless World. Springer Verlag, London. [PDF]
An interesting ethnographical study of handset usability. Their data collection and analysis approaches were in the qualitative tradition of the social sciences. They conducted multiple in-depth and open interviews over the course of the 6 weeks immediately following service acquisition. To understand the context of use, the authors grounded our questions in information that subjects reported in voice mail diaries, a technique they adapted from a paper-based diary study approach (Rieman, 1993). To tie these observations to frequency of telephone use as a characteristic of communicative practice, they collected data on actual calling behavior.
As a result, they outlined four attributes of wireless telephony that articulate the sources of user confusion with the technology.