Chris Johnson is a Principal Engineer with Nokia Siemens Networks. He has been working in mobile telecommunications for the last 18 years, spending most of this time focused on UMTS. He has been involved with LTE for the last 5 years, providing a range of training sessions and generating various guidelines. Chris has previously authored the 'Radio Access Networks for UMTS - Principles and Practice' title. He has also contributed chapters within the 'Radio Network Planning and Optimisation for UMTS' and 'HSDPA/HSUPA for UMTS' titles.