Practical Tips On WCDMA Measurements

Introduction
This is a practical wideband code division multiple access (WCDMA) measurement procedures note. The objective of this note is to present measurement tips and procedures which will help a field-based network technician or RF engineer conduct Node B measurements on WCDMA access networks.

Evolution To WCDMA
In the mid 1980's a second generation (2G) digital system known as the Global System for Mobile Communications (GSM) was introduced for mobile telephony. It significantly improved speech quality over the older analog-based systems and, as it was an international standard, enabled a single telephone number and mobile phone to be used by consumers around the world. It led to significantly improved connectivity and voice quality, as well as the introduction of a whole slew of new digital services like low-speed data. Proving to be very successful, GSM was officially adopted by the European Telecommunications Standardization Institute (ETSI) in 1991. It is now widely used in over 160 countries worldwide.

The success of GSM spurred the demand for further development in mobile telephony, and put it on an evolutionary path to third generation (3G) technology. Along the way, that development path has included 2G technologies like Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). TDMA is similar in nature to GSM and provides for a tripling of network capacity over the earlier AMPS analog system. In contrast, CDMA is based on the principles of spread spectrum communication. Access to it is provided via a system of digital coding.

In 1997 a 2.5G system called the General Radio Packet Service (GPRS) was introduced to accommodate the growing demand for Internet applications. As opposed to the existing 2G systems, it offered higher data rates and Quality of Service (QoS) features for mobile users by dynamically allocating multiple channels. GPRS installs a packet switch network on top of the existing circuit switch network of GSM, without altering the radio interface.

In 1999, the International Telecommunications Union (ITU) began evaluating and accepting proposals for 3G protocols in an effort to coordinate worldwide migration to 3G mobile networks. These proposals were known as International Mobile Telecommunication 2000 (IMT-2000). One of the most important IMT-2000 proposals to emerge was Universal Telecommunications Services (UMTS).

While GPRS is considered the first step in enhancing the GSM core network in preparation for EDGE and 3G, WCDMA is a 3G technology according to the 3GPP standard. It is the digital access system for the UMTS network and is today considered one of the world's leading 3G wireless standards.