Systems and methods of pre-allocating identifiers to wireless devices for use in requesting resources over a random access channel are described. A wireless communication system includes a random access channel over which wireless devices can anonymously send requests for resources. The base stations receiving and processing the anonymous requests reduces the probability of random access channel collisions and conserves the resources needed to support the anonymous requests by pre-allocating one or more codes to select wireless devices. The wireless devices having the pre-allocated codes can transmit a particular code over the random access channel as a request for resources that uniquely identifies the requester.