在CDMA2000中，为了兼容早期的版本，引入了ZONE，基站的登记与寻呼应该是基于ZONE进行，但同时又定义了LAC，为什么还要定义LAC呢？那么他们有什么作用和关系呢？
在爱立信的参数定义中对REG＿ZONE的定义是：Definition: Defines the registration zone to be used for zone-based registration.
A base station’s zone assignment is identified through this parameter.A zone is uniquely identified by this zone number plus the SID and NID of the zone.Zone based registration can be used to reduce the paging load on a system when it is used along with the LAC’s(Location Area Code).The LAC’s are identified by the MSC when pages are sent out.Each LAC encompasses a group of cells.If this grouping is matched with the zones, the BSC can page the mobile more efficiently.This reduces the paging load as blanket paging is avoided.However, the mobile does need to register more frequently, whenever it enters a new zone or the zone timer expires

而对LAC的定义是：Definition Each Cell belongs to zero or more LACs.
Setting Tradeoffs: There is a tradeoff with the total number of LACs supported by one single BSC and registration overhead and probability of missed pages. If a BSC supports too many LACs, that is, each LAC contains very few cells, the mobile will have to register more often in systems with LAC based paging, in order to avoid paging loss. If there are too few LACs, the system approaches a flood based paging system and the paging channel might become the limiting factor.
Additional Comments: Each cell is configured to belong to one LAC, and if it is a border cell, it could belong to multiple LACs.

那么手机跨ZONE要注册，跨LAC要不要注册呢？？？

从上面的定义看，LAC应该也是定义了寻呼的范围的，这就搞不清楚到底ZONE与LAC的区别和分工是什么？本人不甚明白，请高手指教。