Abstract:
A method and system for performing an intersystem handoff of communication with a mobile station (18) between base stations of first (A) and second (B) cellular systems. At the mobile station (18), a quantifiable parameter of a signal transmitted by a second base station of the second system is measured. When the measured value passes through a first predetermined level, the mobile station (18) communicates a signal quality message via a first base station of the first system to a first mobile switching control station. A channel request message is communicated from the first mobile switching station (MSCI) to a second mobile switching station (MSCII) within the second system. At the second base station, a quantifiable parameter of the signal received from the mobile station is also measured. The second base station establishes communication with the mobile station when the measured value passes through a predetermined level.
Abstract:
An apparatus and method of providing communications between standard unmodified terminal equipment over a telephone link that includes a digital wireless link. The digital wireless link introduces substantial time variable delay. In order to pass time sensitive messages over the link, time sensitive messages are recognized and translated into time insensitive messages for transmission over the wireless link. The time insensitive messages indicate the information contained in the time sensitive messages and in the timing of the time sensitive messages. At the receiving end, the time insensitive messages are recognized and the time sensitive messages reconstructed with the appropriate timing.
Abstract:
In a system including a resource (100) which is shared among a number of users, it is difficult to distribute the available capacity of the resources fairly among the users and still maximize resource utilization. Additionally, it is desirable to allow at least some of the control over usage rates to remain with the users, while at the same time avoiding situations where the resource is overloaded. A system and method are disclosed wherein usage rates are selected from among a set of available rates according to a set of persistence vectors.
Abstract:
A communication system that allows a soft handoff to be completed, even when the communications link between the active base station and the mobile station deteriorates before the mobile station (101) has received the handoff direction message. The mobile station maintains a list of base stations that the mobile station (101) is in communication with, referred to as an 'Active Set'. In addition, the mobile station (101) maintains another list of base stations (300) that are proximate to the base stations (300) in the active set. This list is referred to as the 'Neighbor Set'. A memory within the mobile station (101) includes information that would allow the mobile station (101) to demodulate information transmitted from those base stations (300) on the neighbor set. In accordance with the disclosed method and apparatus, the mobile station (101) places a base station (300) in the active set upon including the base station (300) in a pilot strength measurement message (PSMM).
Abstract:
A method and apparatus for rapidly assigning traffic channels to a plurality of mobile stations in a wide area high-speed packet data cellular communication system. Mobile stations transmit access probes on randomly selected access channels to selected base stations to initiate traffic channel assignments. The access probe comprises a pilot preamble, a traffic channel request, and a pilot/data request channel (DRC). The pilot preamble allows the selected base station to easily detect the access probe transmission. The traffic channel request includes data that identifies the mobile station. Immediately after transmitting the traffic channel request, the mobile station begins communicating with the base station on both the forward and reverse communication links. The selected base station immediately supervises the mobile station's transmission power. The mobile station selects from a group of available power control sub-channels. The mobile station selects an available channel and an associated power control sub-channel from the list. In another alternative embodiment, the base station, and not the mobile station, initiates the traffic channel assignment process. A base station controller instructs all base stations within the mobile station's paging radius to transmit a page message on the forward link. The mobile station continuously monitors the forward link and responds to pages addressed to its associated MSI. When a page to the mobile station is detected, the mobile station initiates a traffic channel request. In addition, the mobile station immediately monitors the power control sub-channel that it identified in the detected page message.
Abstract:
A mobile user terminal (402) accesses a packet data network (450) through one or more of several network access points (404-412). One or more control points (432-440) determines which network access point or points the user terminal is to access. Control may be retained in the current control point, or transferred to another control point, whenever it is convenient. There are preferably several routers, each having an associated home agent (418-420) which determines which foreign agents need to be accessed on behalf of each user terminal. There are several foreign agents (422-430), which forward packets received from a user terminal's home agent to the control point currently controlling communications with the user terminal.
Abstract:
A method and apparatus for operating a cellular telephone system that supports performing an inter-system soft handoff is described. A subscriber unit (20) generates a pilot strength measurement report when the pilot channel from a base station (22A...22D) is detected. When a base station controller (24A, 24B) receiving the pilot strength measurement report determines that the base station (24A, 24B) is part of a second cellular telephone system, an inter-system soft handoff request is generated. An admission control subsystem (44) receives the inter-system soft handoff and either grants or denies the request based on the traffic level with the second cellular telephone system. The traffic level may be determined based on link load messages received periodically by the admission control subsystem (44) that are generated by an interface port (32f) coupled to an interconnect (46) between the first cellular telephone system and the second cellular telephone system. The link load message includes peak queue length and average frame rate information.
Abstract:
A method of invoking and canceling voice and data service between a mobile unit and a base station. Using a standard telephone system, the connection for a voice service and a data service is the same. With the introduction of the digital wireless link, the voice connection and the data connection are different. Therefore new dialing commands which indicate the intent of the connection are created. These commands can also be used to designate the intent of the call from a mobile unit capable of data and voice service but not capable of simultaneous voice and data service. They can also be used to invoke simultaneous voice and data services.
Abstract:
In a system including a resource (100) which is shared among a number of users, it is difficult to distribute the available capacity of the resources fairly among the users and still maximize resource utilization. Additionally, it is desirable to allow at least some of the control over usage rates to remain with the users, while at the same time avoiding situations where the resource is overloaded. A system and method are disclosed wherein usage rates are selected from among a set of available rates according to a set of persistence vectors.
Abstract:
In a communications network, a network user communicates through a remote unit (30) with another user via at least one base station (100). The communications network includes a first mobile switching center (MSC-I) which controls communications through a first set of base stations including a first base station (100). The remote unit (30) stores a list of active base stations which has an entry corresponding to each base station with which active communication is established. The first base station (100) has an entry on the list of active base stations. The first base station (100) measures a round trip delay of an active communication signal between the first base station (100) and the remote unit (30). A handoff of the active communication signal is initiated if the round trip delay of the active communication exceeds a threshold if the first base station (100) is designated as a reference base station. Alternatively, the remote unit (30) also stores a list of candidate base stations comprising an entry corresponding to each base station through which active communication may be possible but is not established. A handoff of the active communication signal is initiated if the list of candidate base stations comprises an entry corresponding to a triggering pilot signal.