Abstract:
The wireless local loop system employs cellular technology to provide telephone service to fixed telephones of remote stations (20) having otherwise conventional handsets. The remote station (20) emulates a conventional public switched telephone network by providing an artificial dial tone from the handset of the remote station, after the handset is taken off-hook. The artificial dial tone is locally generated (112) by the remote station. The system, however, delays providing the dial tone if the system is busy, i.e. if the system is under a load condition. To this end, the system monitors load levels (20) and transmits signals to the remote stations indicating load conditions. A remote station (20), prior to granting at dial tone to the user, receives the load condition signals, determines whether the system is currently under load (211) and, if so, defers the dial tone (213). Hence, if the system is under a load condition, such that no lines or frequency channels are available, the user is not presented a dial tone until a line or channel becomes available. By deferring the dial tone until a line or channel is available, the wireless local loop system more effectively emulates a PSTN.
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.
Abstract:
The wireless system includes one or more payphones (12) from which users may initiate payphone calls. A mobile switching center (16) connects telephone calls initiated from wireless payphones to external telephone systems (18) such as the publlic switch telephone network (PSTN). To meter charges incurred during the telephone call within an external system, the external system transmits periodic metering pulses (52, 54) to the mobile switching center. Each pulse is representative of a predetermined amount of money associated with the telephone call. The rate at which the periodic pulses are transmitted to the mobile switching center depends upon the current billing rate and may be affected by, for example, the time of day. Rather than the forwarding all of the metering pulses to the wireless payphone, therefore consuming a portion of the bandwidth available for wireless telephone calls, the mobile switching center (16) calculates a steady state billing rate from the metering pulses, then transmits only the steady state billing rate to the wireless payphone (12).
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 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 novel and improved method and apparatus for performing an inter-system soft handoff is described. In accordance with the present invention, when a subscriber unit crosses from a first cellular system to a second cellular system, a base station controller (20) determines if sufficient network resources are available to conduct an inter-system soft handoff. If so, the base station controller (20) generates a set of signaling messages that cause a call processing resource to be allocated, and for the call to be processed at the second cellular system. The base station controller (20) then perform data-selection and data-broadcast for the call by transmitting data to the subscriber unit (28) by way of the second cellular system as well as via one or more base stations to which the base station controller (20) is directly coupled. The determination as to whether sufficient network resources are available to conduct the inter-system soft handoff is based on the type of connection that exists between the first cellular system and the second cellular system, the number of inter-system calls being conducted, and the frame offset of the call currently being processed.
Abstract:
The layers and protocols of an air interface layering architecture are designed to be modular and can be modified and upgraded to support new features, perform complex tasks, and implement additional functionality. Prior to commencement of data communication between a first entity (e.g., an access terminal) and a second entity (e.g., a radio network), a set of layers and/or protocols is selected for negotiation. For each selected layer and protocol (i.e., each attribute), a list of attribute values considered acceptable to the first entity is determined. The selected attributes and their associated attribute values are sent from the first entity and, in response, a list of processed attributes and their associated lists of processed attribute values are received. Each list of processed attribute values includes attribute values considered acceptable to the second entity. The layers and protocols in the first entity are then configured in accordance with the received list of processed attributes and their associated processed attribute values. Other features related to configurable layers and protocols are also provided.
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 system provides wireless data service. The system includes a wireless modem (42) configured to be coupled to a terminal equipment unit (40) over a wireline broadcast medium (56). A network unit (58) is coupled to the wireless modem (42) over a wireless link connection. A network remote server (60) is coupled to the network unit (58). The network remote server (60) provides IP address information in response to terminal equipment unit address request messages for terminal equipment units (40) coupled to the network unit (58). In addition, a local server (52) is couple to the wireless modem (42). The local server (52) provides IP address information in response to terminal equipment unit (40) address request messages from terminal equipment units (40) coupled to the wireline broadcast medium.
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.