These companies manufacture and/or provide services for the GSM cell phone industry. They also have information on their websites regarding GMS standards, implementation, and theory. GSM stands for Global System for Mobile communications (originally from Groupe Spécial Mobile). 
GSM Manufactures & Services

3G Americas, LLC 425-372-8925 The mission of 3G Americas is to promote and facilitate the seamless deployment throughout the Americas of GSM and its evolution to 3G and beyond. 3G Americas is committed to working with regulatory bodies, technical standards bodies, and other global wireless organizations to promote truly seamless interoperability and convergence. 3G LTE Tutorial - 3GPP Long Term Evolution Information, overview, or tutorial about the basics of the 3GPP / 3G LTE, the long term evolution plans for the next generation of cellular telecommunications services. By Ian Poole, Radio-Electronics.com 3GSM World Congress As befits our move to a larger, more exciting venue we are pleased to bring you the most heavyweight line-up of speakers and a diverse, multi-faceted congress agenda which caters for gevery sector of the extended mobile industry value chain. Design Considerations for an Ultra-Compact GSM Radio Solution Article in RF Design, by Mike Durrant and Andreas Nitschke. Digital Sampling Power Analyzer for GSM and CDMA By Richard H. Blackwell, Boonton Electronics. ETSI - European Telecommunications Standards Institute +33 (0)4 92 94 42 00 / France An independent, non-profit organization, whose mission is to produce telecommunications standards for today and for the future, and is officially responsible for standardization of Information and Communication Technologies (ICT) within Europe. These technologies include telecommunications, broadcasting and related areas such as intelligent transportation and medical electronics. Evaluation of GSM and GPRS Systems in Emergency Telemedicine The objective of this paper is to carry out a practical evaluation of the performance of the GSM and GPRS systems in the transmission/reception of images and video as well as Patient Record and biosignals in emergency cases. From ZDNet. Global System for Mobile Communication Whitepaper by the International Engineering Consortium. Global System for Mobile Communication (GSM) Tutorial From the International Engineering Consortium. Global System for Mobile Communications Wikipedia article. GSM & WCDMA Seamless Network White paper from Ericsson. GSM and WCDMA—Common Network Approach From Ericsson, by Ros-Marie Furtenback, Torsten Hunte, Dalibor Turina and Ulrik Wahlberg. GSM Basics Tutorial (5 pages) A tutorial, description, overview about the basics of GSM - Global System for Mobile communications with details of its radio interface, infrastructure technology, network and operation. From radioelectronics.com. GSMArena.com GSM handset information, includes product reviews, opinions, forums, manuals, and ringtones. GSM Handset Vulnerabilities, Part I: RF Performance From CommsDesign, by Brian Senese and Laurent Ronc. GSM Design Library E8859A GSM Design Library enables you to assemble a GSM system design using behavioral models and examples, from Agilent Technologies.

GSM History A description of the development or history of GSM, Global System for Mobile communications developed out of the original Groupe Special Mobile pan_european system. From radioelectronics.com. GSM Mobile Phones and Linux By Dave Davey. GSM Resource Channel Access instant solutions for your most demanding GSM problems. Our vast IT library puts more IT information at your finger tips. GSM Specifications Information from TelecomSpace Telecom Tutorials and Forum. GPRS Technology Tutorial (5 pages) A sumary or tutorial describing GPRS, the General Packet Radio Service, the technology used to provide higher speed data over the GSM cellular telecommunications network. From radioelectronics.com. GSM World / GSM Association +44 (0)20 7759 2300 / London, UK Global trade association that exists to promote, protect and enhance the interests of GSM mobile operators throughout the world. HSDPA Testing Test methodologies must evolve as GSM and WCDMA combine with High-Speed Downlink Packet Access. Dr. Salim Manji, Spirent Communications -- Test & Measurement World, 2/1/2006. Implementation Effects on GSM’s EDGE Modulation ETSI Standards by Stephan V. Schell. Investigation Into the Performance of EOTD for GSM Users in Telematics Applications White paper from Silicon.com. LTE Advanced for IMT 4G Overview, information, tutorial about the basics of LTE Advanced, the 4G technology being called IMT Advanced being developed under 3GPP. By Ian Poole, Radio-Electronics.com Mobile Terms and Acronyms From GSM World. Overview of EDGE Cellular Summary about the 2.5 G EDGE cellular technology and system including a description of its use of 8PSK, and packet switched data technology. Overview of the Global System for Mobile Communications: GSM Information by by John Scourias. Performance Modelling of GSM/GPRS Cells With Different Radio Resource Allocation Strategies This paper presents an analytical model for the performance evaluation of GSM/GPRS cells with different resource allocation schemes - White paper from ZDNet.