bit capacity than the air interface, there should be no limitation of service. As a result, planning capacity for a single-base-station-to-MSC link is a simple matter of adding up the total capacity of the base station's air interface and making sure that the link is a little bigger. We can use traffic engineering principles to deter- mine just how much bigger it should be. The challenge in this arena is not planning for capacity to a single base station but rather planning the transport and estimating transport costs for a network growing by the addition of new base stations. Normal telephone networks grow by expanding capacity from point to point. Wireless base sta- tions, on the other hand, do not gain capacity as a system grows. Radio spectrum ca- pacity at a single base station is typically fixed, and we grow the total network capac- ity by splitting cells and adding new base stations. We have more links with the same demand distribution rather than the same links with growing demand. Of course, changing technology, services, or facilities on the radio link or in the wire- less network are likely to require changes to transport facilities. In planning transport facilities, it would be appropriate to ask if conditions such as these are likely to arise: Acquisition of more radio spectrum will increase capacity at existing base stations, re- quiring additional transport. If a cdmaOne wireless network is being upgraded to cdma2000, then it will be necessary to evaluate base-station-to-MSC transport capacity and upgrade that capacity wherever the new air-interface capacity exceeds the capacity of the existing pipe. If a CDMA system is being modified to support wireless local loop (WLL), particularly at high data rates or for large groups of subscribers, additional base-station-to-MSC trans- port might be needed. If the base-station-to-MSC pipe might be converted to an Internet Protocol (IP) packet pipe, then greater efficiency could reduce the size of the pipe needed after the conversion. 13.2.2 Signaling with AN