摘要:
A method and apparatus for coordinating the transfer of communications control from one independent radio communications system to another is disclosed. A remote unit which communicates data messages is associated with a home system which has a plurality of fixed sites and overlapping radio coverage areas. As the remote unit travels away from its home system, communications may be maintained by providing radio coverage from an independent roam system. The last message received by the home and roam systems from the remote unit has the associated radio signal strength and time of reception stored at each system. When a current message is transmitted by the remote unit and both the home and the roam system receive the message, the roam system time stamps the message and calculates the signal strength associated with the current message. If the amount of time elapsed between the last and the current message exceeds a predetermined amount of time or if the signal strength exceeds a predetermined threshold, the roam system requests transfer of control of the processing of the current message from the home system. When the home system receives this request, it calculates the difference in signal strength between the signal strength of the current message as received by the roam system and the signal strength of the current message as received by the home system. If the difference exceeds a predetermined amount, the request of the roam system to further process the message is granted.
摘要:
A communications system for carrying messages via a radio channel between one central site of a plurality of central sites and a plurality of two-way remote data units is disclosed. Each central site has a radio coverage area and each remote unit has a unique address and association with one of the central sites. When a message addressed to one of the remote units is received in a central site, a file of remote unit addresses is searched to find the location and central site association of the remote unit to which the message is addressed. If an address match is found indicating that the remote transceiver is in the coverage area of the message-receiving central site, the addressed message is stored and transmitted in that site. If an address match is found indicating that the remote transceiver is in another central site, the addressed message is conveyed to that site for transmission.
摘要:
A write-once read-many memory system (10) for electronically securing a select portion of memory from being overwritten or erased. Memory system (10) includes one or more storage cells (25) for providing electronic storage of information. A control cell (13) is used for controlling writing and/or erasing access to the storage cells (25). Control logic (11) is provided to control access to the control cell (13). Control cell (13) and control logic (11) are used as a gate to provide selective access to storage cells (25) through write control line (19) and erase control line (21). Storage cells (25) can only be accessed when the control cell (13) in an appropriate logic state.
摘要:
A communication device (100) includes three levels and at least one feature and at least one protocol for communicating with other communication devices. The three levels are high level or user ergonomics (302), common level or feature/protocol (310), and low level or hardware platform (318). The feature/protocol level (310) is adapted for controlling the at least one feature and the at least one protocol. The user ergonomics (302) includes a first interface (304) coupled to the feature/protocol level (310) for allowing the user ergonomics level (302) to change without affecting the feature/protocol level (310). The, hardware platform (318) includes a second interface coupled to the feature/protocol level (310) for allowing the hardware platform (318) to change without affecting the feature/protocol level (310) or the user ergonomics level (302).
摘要:
In radio processing control (11), a plurality of architectural layers (270, 290, 390) separate at least one of a plurality of tasks (272) from another task (292). For communicating among the tasks within (274, 276, 278) or across (229, 239) the layers, a buffer (300) for each of the tasks is provided by a communication resource (602). A messaging protocol for passing information from the tasks is defined to be a predefined information packet having a header (700) preceding any optional data. A flag portion (701) of the header designates the information as intralayer or interlayer. If the information is interlayer (229, 239), an identifier portion (703, 704) of the header identifies the source (272) of the information and an operation portion (702) identifies an operation code.