This work is devoted to providing an explanation of the newly emerging wireless access standards for Personal Communications Services (PCS). PCS is a new concept which will expand the horizon of wireless communications beyond the limitations of current cellular systems to provide end users with the ability to communicate with "anyone, anywhere, anytime". Because of the inherent nature of mobility, which is characteristic of personal communications, wireless communications and PCS have become inseparable concepts. In particular, PCS will critically depend on wireless technologies for the mobile-to-network access portion of the service, which is referred to as the common air interface. The topic of this book is the wireless access technology used for the common air interface in order to support PCS. The book presents clear tutorial expositions of the main digital technology elements employed for wireless access systems. The main objective is to look at all the important basic technical elements necessary in understanding wireless access systems, so that the reader can obtain an overall view of the technology quickly and systematically. The book also reviews the common air interface standards for PCS, and in doing so has two main objectives. The first is to sift out and summarize important elements of the standards, which are buried in the the standards literature, in unfamiliar terms, notations, and abbreviations. The second objective is to expand some of the more important elements to explain the intent and significance of the written words of the standards.