Scope of This Document This specification applies to cdma2000 mobile stations and base stations@ which are enhanced to support the E-UTRAN and cdma2000 1x interworking and Interworking Solution (IWS). These requirements ensure that a compliant mobile station can obtain interworking service through any base station conforming to this standard. These requirements do not address the quality or reliability of that service@ nor do they cover equipment performance or measurement procedures. This specification is primarily oriented toward requirements necessary for the design and implementation of mobile station. As a result@ detailed procedures are specified for mobile station to ensure a uniform response to all base station or IWSs. Base station and IWSs procedures@ however@ are specified only to the extent necessary for compatibility with those specified for the mobile station. This specification includes provisions for future service additions and expansion of system capabilities. The architecture defined by this specification permits such expansion without the loss of backward compatibility to older mobile stations.