Abstract: 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.

Abstract: A system and method for performing base station initiated call setup is provided. A base station initiated call setup may be utilized to establish a test call, to deliver a packet data services call to a subscriber unit, or to reactivate a dormant packet call. The base station transmits a BS Service Request message to the mobile switching center, requesting initiation of the call. The mobile switching center will authorize the call if the call to be set up is directed to a subscriber unit located within the service area of the base station and if the service option to be used is authorized for the particular subscriber unit. The mobile switching center will allow or disallow the call depending on the state of the subscriber unit. The mobile switching center transmits a BS Service Response message to the base station, conveying the result of processing the BS Service Request message.

Abstract: A method and apparatus for providing soft handoff in a mobile communication system. In current systems is that the members of active set are determined in accordance with comparisons of measured pilot energy with fixed thresholds. However, the value of providing a redundant communication link to a mobile station depends strongly on the energy of other signals being provided to the mobile station. In the present invention, the signal strengths of other base stations in communication with a mobile station are considered when determining whether adding a base to that set of base stations in communication with the remote station is of sufficient value to justify the impact on system capacity.

Abstract: 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.

Abstract: 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.

Abstract: An apparatus for providing authentication of a mobile station in a wireless communication system. The present invention takes the number dialed by the mobile station user and computes the 24 bit number (AUTH.sub.-- DATA) for authentication in accordance with a hashing function that has the following characteristics. The hashing function takes as its input at least the entire dialed digit string contained in the request for service and the number of digits. In a preferred embodiment, the ordering of the digits affects the result, as well as, the values of the digits. The preferred embodiment of the hashing function also accepts some or all of the mobile station identifier data. The function provides as output a number of suitable size for input to a second calculation of an authentication signature, such as the 24 bits required for AUTH.sub.-- DATA. The output number is created in such a way that there is a minimum likelihood that other sets of dialed digits may create the same result.

Abstract: 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.

Abstract: 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.

Abstract: An RF circuit switch system having particular use in an antenna diversity scheme for a CDPD system relies upon a comparison between current signal values on a selected antenna and a predetermined value based upon previous signal values measured on the same antenna. This comparison determines whether switching will occur from one antenna to another. Normally, the predetermined value will be adjusted based upon present signal strength on the selected antenna. Switching is normally attempted when there is a drop of approximately 10 dB in the signal strength of the selected antenna. If the signal strength in the other antenna is found to be less than that of the original antenna upon switching, an automatic switch back is carried out.

Abstract: A method of electronically moving portions of several different images on a CRT screen includes the steps of: storing a first image in one section of an image memory, and storing a second image in a different section of the image memory; storing control bits in a control memory which define high and low priority viewports on the screen and correlate portions of the first and second images to the high and low priority viewports respectively; displaying, in response to the stored control bits, the entire portion of the image in the high priority viewport and only the non-overlapping portion of the image in the low priority viewport by transferring the image portions from the image memory to the screen with no frame buffer therebetween; modifying at least some of the stored control bits to change the priorities of the high and low priority viewports to low and high respectively; and repeating the displaying step, in response to the modified control bits, to display the entire portion of the image in the new high

Abstract: A system for electronically displaying portions of several different images on a CRT screen comprises: a memory for storing a complete first image as several pixels in one section of the memory and a complete second image as several other pixels in another section of the memory such that the total number of stored pixels is substantially larger than the number of pixels on the screen; a logic circuit for reading a sequence of the pixels at non-contiguous locations in the first and second images and for transferring them, in the sequence in which they are read, to the screen for display with no frame buffer therebetween; the logic circuit for reading including a module for forming non-contiguous addresses for the pixels in the sequence in which they are read with the address of one word of pixels being formed during the time interval that a previously addressed word of pixels is being displayed on the screen.

Abstract: 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.