Proposals have been made to provide a wireless communication system for passengers in a vehicle such as for aviation use to allow cell phones to be used on an aircraft when in flight. For in-vehicle wireless pico-cells such as those proposed for use on aircraft or in any other suitable moving vehicle (e.g. train, bus, etc.), security concerns are of utmost importance.
An in-vehicle wireless CDMA pico-cell has been proposed for use in an aircraft where, for example, a passenger may activate a personal cell phone that includes not only a wireless wide area network transceiver to communicate for example with ground based networks, but also where the transceiver can operate as a short range wireless local area network transceiver that may communicate for example with an on aircraft CDMA pico-cell. The in-vehicle wireless CDMA pico-cell performs many of the functions of cell towers that are used in CDMA systems on the ground and may also relay calls to an aircraft satellite communication antenna mounted in the aircraft to communicate wireless calls from the CDMA pico-cell to the ground cellular network. A signal is transmitted from the plane's satellite antenna to an orbiting satellite and global positioning technology in the satellite may be used to track the location of the user or telephone signal as the aircraft moves. Any other suitable off-vehicle air-to-ground link techniques may also be utilized.
The in-vehicle CDMA pico-cell uses standard cellular based station transceiver technology and a low power transmitter since it is designed to provide cellular coverage to a small area for a relatively high number of users. A base station controller (BSC) and antenna subsystem is provided as part of the in-vehicle wireless CDMA pico-cell. The in-vehicle wireless CDMA pico-cell may provide for example both voice and data communications to allow text messaging, internet access, email and other voice and non-voice services. However, use of wireless mobile stations in an aircraft or other vehicle can cause safety concerns. For aircraft, government regulations require that cell phone transmissions stop when the aircraft ascends or descends. Details as to how to enable system selection, safety requirements and other aspects relating to an in-vehicle CDMA pico-cell have not been addressed.
In addition, preferred roaming lists (PRL) are known which are stored in wireless mobile stations, such as cell phones or any other suitable devices and may be originated for example by a system operator through a server and may be provided in the mobile station when it is initially purchased or may be downloaded over the air when a mobile station is initially registered to one or more systems, or at any other suitable time. A preferred roaming list (PRL) is an indexed list of systems stored in a wireless mobile station that defines, for example, systems that the mobile station can access and those systems that are not accessible to a user. As used herein a PRL is not limited to a preferred roaming list in a CDMA system but also refers to any preferred list that provides a wireless mobile device with one or more systems to communicate with. For example, each CDMA ground system is uniquely identified by the combination of a system identification code (SID) and a network identification code (NID) pair and each CDMA base station broadcasts its SID and NID in system overhead messages. Other systems can provide suitable identification information so that when a mobile station moves from one cell to another or one geographic area to another the mobile station can determine which system it is permitted to use and which channels it is allowed to access.
A PRL may include two tables referred to as an acquisition table and a system table. An acquisition table typically contains an indexed list of radio frequency channels for the mobile station to search and each entry may describe the radio frequency environment of a particular area. A system table may contain an indexed list of systems, referenced by SID and NID pairs. Each entry refers to a specific radio frequency environment and each system belongs to a geographical group which is identified by, for example, geographical area identification data. In addition, relative priority among the different systems is specified within a geographical group and roaming display behavior can be specified indicating which system may be a preferred roaming system and those systems that are not allowed to be used by a particular user. Hence preferences can exist within geographic areas and an operator can specify preferences as to which networks a mobile station can access.
Among other advantages, a PRL speeds up channel acquisition and provides the flexibility to specify a “roam” or “not roam” condition indicator on a mobile station's display. For example, operators can specify a mobile station's search behavior in a home market or roaming markets. PRLs have been extended for multimode mobile stations that support for example CDMA, GSM systems or UMTS systems. By way of example, with a multimode enabled wireless mobile station, at power up, the wireless mobile station may try to acquire the priority CDMA system which may be for example indexed as “0” in an acquisition table (highest priority). If the wireless mobile station successfully acquires that system or any CDMA system, the wireless mobile station may choose that CDMA system and provide service. If the mobile is unable to acquire a CDMA system in the PRL, the mobile may try to acquire a different type of system such as a GSM system which may be indexed as “1” in an acquisition table (lower priority). These indexes of different systems may be indexed for the geographical area identification data (e.g. geographic groups of systems). For example these multiple systems may cover a common geographic area defined by a system operator such as the City of Los Angeles since multiple different systems may be setup to cover Los Angeles. Because the CDMA service is indicated as most preferred in this particular geographic area, even though GSM service is acquired, the wireless mobile station may perform periodic reselection of CDMA services since it is the most preferred system in the acquisition table. However, suitable acquisitions schemes for mobile stations that can communicate on WWAN and in-vehicle CDMA wireless pico-cells are also needed.
Accordingly, a need exists for an apparatus and methods that suitably support an in-vehicle CDMA pico-cell system.