摘要:
A point-to-multipoint (PTM) radio communication system (20`) includes a cellular radio infrastructure (22) having base stations (32) implemented in satellites (34) placed in low earth orbits (38). PTM subscriber radios (24) share common cellular radio infrastructure (22) multipoint channels (52) to engage in a common PTM communication session while the cellular radio infrastructure (22) also conveys point-to-point communications. The shared multipoint channels (52) are operated in according with different protocols to deliver system information to PTM subscriber radios (24), to provide access to PTM subscriber radios (24), to provide synchronization, to originate a PTM monolog and to be one of many targets of a PTM monolog.
摘要:
A point-to-multipoint (PTM) communication system (20) includes a cellular radio infrastructure (22) having base stations (32) implemented in satellites (34) placed in low earth orbits (38). PTM subscriber radios (24) share common cellular radio infrastructure (22) multipoint channels (52) to engage in a common PTM communication session while the cellular radio infrastructure (22) also conveys point-to-point communications. A group control computer (28) constructs a channel list (126) which is downloaded to PTM subscriber radios (24). The channel list (126) identifies multipoint channels (52) and indicates when and where the channels (52) are active. Without emitting transmissions to the cellular radio infrastructure (22), PTM subscriber radios (24) autonomously switch to new multipoint channels (52) in response to their current time and location and the channel list (126).
摘要:
A group radio communication system (20) includes a group controller (24) which communicates through a satellite-based packet switched data communication network (22) to converters (28). The converters (28) are located within radio coverage areas (36) of various radio sub-networks (26). Each radio sub-network (26) includes a base station (32), controller (30) and any number of subscriber radios. The controllers (30) manage point-to-multipoint communications between subscriber radios (34) within their radio sub-networks (26), and the group controller (24) manages point-to-multipoint communications between radio sub-networks (26). The converters (28) translate between protocols (38, 38′) established for communications within specific radio sub-networks (26) and a protocol (56) established for communication over the packet switched data communication network (22). The group controller (24) duplicates and distributes packets (118) originating in one radio sub-network (26) to other radio sub-networks (26).
摘要:
A communication system (10) includes a group call controller (GCC) (26) for use in establishing, maintaining, and controlling the provision of group call services within the communication system (10). To initiate a group call session for a particular subscriber group, a group call request is delivered to the GCC (26) that identifies the desired group. Upon receipt of the request, the GCC (26) coordinates the delivery of group call notification to the members of the identified group to notify the members of the initiation of the group call session and to identify to the members a physical communication channel (36) to be used by each member to participate in the group call. Upon receipt of the notification, the group members each tune to a corresponding physical communication channel (36) and are immediately made part of the group call. The group members are not required to make any transmissions on the physical channel (36) to participate in the group call.
摘要:
An interworking unit (14) for providing an interface between a digital communication network (12) and a public switched telephone network (PSTN) (16) includes a de-vocoder (30), a protocol termination unit (32), and a signal combiner (34) for processing signals being transferred from the digital network (12) to the PSTN (16). A digital communication signal received by the interworking unit (14) from the digital network (12) is processed by both the de-vocoder (30) and the protocol termination unit (32). The outputs of the de-vocoder (30) and the protocol termination unit (32) are then combined into a uniquely formatted signal that is then delivered into the PSTN (12). Similar functionality is also provided for processing signals in the reverse direction. The interworking unit 14 is capable of processing signals traversing the interface between the networks (12, 16) without a priori knowledge of the signal type being processed.
摘要:
An interworking unit (14) for providing an interface between a digital communication network (12) and a public switched telephone network (PSTN) (16) includes a de-vocoder (30), a protocol termination unit (32), and a signal combiner (34) for processing signals being transferred from the digital network (12) to the PSTN (16). A digital communication signal received by the interworking unit (14) from the digital network (12) is processed by both the de-vocoder (30) and the protocol termination unit (32). The outputs of the de-vocoder (30) and the protocol termination unit (32) are then combined into a uniquely formatted signal that is then delivered into the PSTN (12). Similar functionality is also provided for processing signals in the reverse direction. The interworking unit 14 is capable of processing signals traversing the interface between the networks (12, 16) without a priori knowledge of the signal type being processed.
摘要:
A system for encrypting and verifying a data packet includes an encryptor (20), a decryptor (30), an error detector (40), and switch (65). A data packet with embedded error detection codes is encrypted by the encryptor (20), decrypted by the decryptor (30), and then the error detector (40) examines the embedded error detection codes to determine if the data packet has had errors introduced during the encryption/decryption process. When errors are detected, the switch (65) is opened to keep erroneous data from being transmitted.
摘要:
A digital cellular telecommunication network (30) uses transcoders (50) which vocode voice using a maximal lossy compression algorithm which conserves spectrum usage. A call path for an intercepted call is looped from an outer space satellite (32) network into a terrestrial gateway (34). Compressed call data for each of two half-calls in this call path are duplicated at any of the network nodes and inserted into the opposing half-call. In addition, the compressed call data are decompressed in a gateway transcoder (50), combined in a conference bridge (90), and routed to a monitoring center (60). A subscriber unit (36), a second device (48), and the monitoring center (60) all receive call data which has experienced only one compression/decompression cycle.
摘要:
A method for providing location based intercept in a satellite communications system (10) includes the steps of determining a location area of a party (220), determining whether the location area is one to be monitored (240), and conditionally routing the call to an intercept gateway (250). An intercept gateway (32) is a gateway that intercepts all or part of the calls received, and can also function as a home gateway (30) or a visiting gateway (40).
摘要:
A system and method provides signaling privacy for communications between nodes of a communications network (30). Multiple logical links exist between distinct network nodes (38-40, 42, 50-53) of the communication network (30). Signaling privacy is achieved by a subscriber unit (80) providing encryption/decryption of signaling data messages at the messaging level. The subscriber unit (80) employs a signaling encryptor/decryptor (86) along the signaling path, which enables the signaling data messages to be separately encrypted from data on the traffic channel. The encrypted signaling data can then be sent along a different logical link from the traffic, while maintaining cipher key synchronization between the signaling encryptor/decryptor (86) and a network encryptor/decryptor (78) at a remote end of the logical link which transports the encrypted signaling data.