A base station receives a first identifier (e.g., pseudo ESN) from the wireless device and assigns an index to the wireless device. The base station generates a second identifier (e.g., a dynamic ESN) for the wireless device based on the first identifier and the index. The second identifier is unique among all wireless devices communicating with the base station and may also be unique among other wireless devices communicating with other base stations. The base station generates a code (e.g., a PLCM) for the wireless device based on the second identifier. The wireless device generates the second identifier and the code in similar manner. The second identifier and code may be used for communication between the base station and the wireless device.