UMTS Signaling: UMTS Interfaces, Protocols, Message Flows and Procedures Analyzed and Explained by R. Kreher, and T. Ruedebusch:
From an Amazon reviewer: "...This is a great reference book for UMTS and does a great job of explaining real world examples of protocol flows. I have all of the other "standard issue" UMTS book both on the RAN and Core, this is the only one that covers all aspects. ..."

Radio Access Networks for UMTS: Principles and Practice by Chris Johnson:
From an Amazon reviewer: "...I've been to a few training courses presented by Chris Johnson. This book provides a good reflection of his knowledge and clear presentation style. I like the way that a lot of the descriptions are based upon following the flow of data through the protocol stack. There are some good examples of what happens to the speech and data service bits as they are passed between layers. I like the tables which illustrate how the number of bits change during each phase of physical layer processing. This is shown for DCH as well as HSDPA and HSUPA connections. Some parts of the radio network planning sections are similar to those found in other books but there are sections which do not appear elsewhere, e.g. analysis of maximum neighbour list lengths. Link budgets are also presented and described in depth...."

WCDMA for UMTS: HSPA Evolution and LTE by H. Holma and A. Toskala:
From an Amazon reviewer:"...Whoever read the 3GPP standardization documents for UMTS knows how hard and time consuming it is to extract all the relevant information. Holma and Toskala's book is not just a collection of the 3GPP documents it is bringing light into them. Many plots of system simulations are given. It certainly helps you saving valuble time in getting up to date information about one of the hottest telecommunication applications nowadays. Read this book and you will understand the UMTS standard..."