Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to physical layer configuration of wireless communications.
Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
Release-99 is a standard that defined dedicated channels between a user equipment (UE) and a base station or node B based on orthogonal variable spreading factor (OVSF) codes. Some wireless networks continue to rely on Release-99 channels for various services. For example, a voice call may be carried over a Release-99 dedicated channel (DCH). Release-99 channels allow for a compressed mode (CM) operation to allow a UE to perform measurements on another frequency or another radio access technology (RAT). The Release-99 CM operation may reduce a spreading factor for a DCH. Such spreading factor reduction may present difficulties for network management of a code tree or may result in additional interference when non-orthogonal codes are used. In view of the foregoing, it may be understood that alternative methods of compressed mode operation are desirable.