摘要:
Method and apparatus for encrypting transmission traffic at separate protocol layers L1, L2, and L3 so that separate encryption elements can be assigned to separate types of transmission traffic, which allows the implementation of different levels of encryption according to service requirements. Encryption elements use variable value inputs, called crypto-syncs, along with semi-permanent encryption keys to protect from replay attacks from rogue mobile stations. Since crypto-sync values vary, a method for synchronizing crypto-syncs at the mobile station and base station is also presented.
摘要:
A system and method for providing mobile switching center (MSC) initiated service negotiation in a wireless communication system. If a new call arrives for a subscriber unit while the subscriber unit is already on the traffic channel, a change in the service configuration may allow the subscriber unit to receive the new call while preserving the old call. MSC initiated service negotiation may be used to establish the change in service configuration. The MSC transmits a Change Service Command message to the base station in whose coverage area the subscriber unit is located. The Change Service Command proposes a new service configuration to accommodate both the old and the new call. The base station, subscriber unit, and MSC may interchange further messages to modify the proposed service configuration if necessary. Messages are exchanged until the base station, subscriber unit, and MSC reach an agreement regarding the new service configuration. The present invention also provides support for soft handoff. The new service configuration is presented to all target base stations involved in the soft handoff, so that the subscriber unit may make use of the new service configuration while in soft handoff.
摘要:
A method for generating a broadcast challenge value includes the steps of applying a first updating algorithm to the most significant bits of the broadcast challenge value, and applying a second, distinct updating algorithm to the least significant bits of the broadcast challenge value. The updating algorithms can be maximal-length shift registers or other forms of pseudorandom noise generator. The sequence of successive unrepeated values can be extended for either one or both sets of bits by inserting an all-zeroes value once during the period of time before which an update value recurs. System-wide synchronization can be achieved via a global time reference.
摘要:
A method and apparatus for operating a cellular telephone system that supports performing an inter-system soft handoff is described. A subscriber unit generates a pilot strength measurement report when the pilot channel from a base station is detected. When a base station controller receiving the pilot strength measurement report determines that the base station is part of a second cellular telephone system, a inter-system soft handoff request is generated. An admission control subsystem receives the inter-system soft handoff and either grants or denies the request base on the traffic level with the second cellular telephone system. In a preferred embodiment of the invention, the traffic level is determined based on link load messages received periodically by the admission control subsystem that are generated by an interface port coupled to an interconnect between the first cellular telephone system and the second cellular telephone system. The link load message include peak queue length and average frame rate information.
摘要:
An interconnection circuitry for two local area contention networks which is adapted to jam the respective networks when stations on both sides of the interconnection circuitry attempt transmission. If stations on opposite sides of the interconnect circuitry begin transmitting at the same time, the interconnect circuitry operates to place a high signal on the channel of each network and all stations will detect that the data is garbled and discard it.
摘要:
A system and method for providing subscriber unit or base station initiated service negotiation in a wireless communication system. Message generators in the mobile switching center, base station, and subscriber unit compose messages to be transmitted in association with the service negotiation, while message processors analyze received messages in order to direct the message generators to compose the appropriate response messages. In a subscriber unit initiated service negotiation, the subscriber unit initiates service negotiation by sending a Service Request Message to the base station containing the requested service configuration. The base station then checks with the mobile switching center to ensure that the requested service configuration is authorized for use by the particular subscriber unit. In a base station initiated service negotiation, the base station determines the appropriate service configuration to be used, and includes it in a Change Service Request message transmitted to the mobile switching center. The mobile switching center checks the service configuration to ensure that it is authorized for the particular subscriber unit. The present invention also provides support for service negotiation during soft handoff. In soft handoff using circuit mode transport for inter base station communication, the new service configuration is presented to all target base stations via the mobile switching center.
摘要:
In a digital communication system for communicating digital information, the digital communication system having a forward link and a reverse link, a system and method for communicating a data packet. The system comprises a communicating transceiver, from among a number of digital transceivers, for sending the data packet on a random access channel over the reverse link and for receiving the digital information from the forward link. The system also comprises a base station for receiving the data packet on the random access channel from the reverse link and for sending the digital information over the forward link. The digital transceivers share the random access channel. The digital transceivers have a bandwidth demand. The system may also include a dedicated channel for communicating the data packet between the communicating transceiver and the base station and a processor for switching from the random access channel to the dedicated channel when the bandwidth demand exceeds a first threshold, and for switching from the dedicated channel to the random access channel when the bandwidth demand drops below a second threshold. The system is well suited for use in CDMA applications.
摘要:
A cellular digital packet data (CDPD) system includes a mobile data base station (MDBS) configured to interface easily with an advanced mobile phone system (AMPS). The elements of the MDBS are arranged on modules and the functionality of the MDBS is divided among the modules to facilitate flexibility, compactness and quick expansion of the MDBS. To further facilitate compactness, the MDBS includes a transceiver/modem board which uses a single chip to carry out delta-sigma modulation. In order to maintain the integrity of CDPD transmission, a channel hopping scheme is used based upon avoidance of AMPS channel use. A distinctive protocol is used to encapsulate control/query/response data for transmission throughout the CDPD system. This protocol also facilitates easy control of each MDBS throughout the system.