This invention relates to an arrangement for efficiently providing an up to date neighbor list for base stations serving a wireless cellular telecommunications call. The neighbor list is required by a mobile station measuring signal strengths of signals for surrounding base stations in order to locate base stations from which the mobile station can receive strong signals. When one base station receives a revised neighbor list from another base station, it receives a revised neighbor list from another base station, it receives a time stamp identifying when that revised neighbor list was created. Thereafter, when a request for data from a base station is transmitted, it is transmitted with that time stamp; no neighbor list is returned if the time stamp matches the time stamp stored with the neighbor list of the base station receiving the request.