Abstract: A method is disclosed of reducing data loss during cellular handoff of a mobile among base sites by detecting an end-of-line signal by a fax adapter (13a or 106a) from the transmitting fax, buffering (13b or 106b) subsequent fax information, and transmitting filler bits in place of the EOL and buffered information.

Abstract: This invention relates to apparatus and a method for provision of diversity in reception in a communications system such as the GSM cellular radio system. A received call of low quality is received through a first of two antennas (15, 16) and through first of a plurality of receivers (10-14). A spare receiver that is not required for receipt of a call is identified and the spare receiver is switched to receive the call through the second antenna. The spare receiver is tuned to the frequency of the call of low quality and the calls are diversity combined through the first receiver and the spare receiver.

Abstract: A power combiner including a plurality of phasing transmission lines (122) supporting a set of amplifiers (104) coupled thereto, and a plurality of matching transmission lines (124). The set of amplifiers (104) having a selectable number of amplifiers between a minimum and a maximum value. Each of the matching transmission lines (124) is coupled to one of the phasing transmission lines (122) at one end and coupled to a common node (126) at the other end. Each of the matching transmission (124) lines has a substantially equivalent characteristic impedance determined according to a function of the minimum and the maximum number of amplifiers in the set of amplifiers (104).

Abstract: A method for handover in a cellular system is provided which includes periodically scanning from neighboring cells, traffic channels of a serving cell to determine channel metrics. If the channel metrics exceed a threshold, validating the serving cell identity by verifying traffic channel color code. The channel metrics are then periodically transferred to the serving cell where a handover decision is made.

Abstract: A method and apparatus for authenticating a roaming subscriber. In a preferred embodiment, a subscriber receives a challenge that is in a format of a local authentication protocol, and determines whether the local authentication protocol is the subscriber's home system authentication protocol. If it is not, the subscriber converts the challenge into a format (e.g., bit length) compatible with its home system authentication protocol, and processes the converted challenge with the subscriber's secret key and authentication algorithm into an authentication response. The authentication response is converted to be compatible with the local authentication protocol, and transmitted to a local system communication unit. The challenge and response is then forwarded to the subscriber's home system for similar conversion and processing, and subscriber's response is compared against a home system generated response.

Abstract: A method and apparatus for circuit-switched and single-user traffic channel packet data communication in a cellular radiotelephone system, including a base station and mobile data unit both operable for establishing either a circuit-switched data call connection or a single-user connectionless packet data traffic channel via a radio channel, and communicating packet data over the established radio channel.

Abstract: A receiver (900) employs a method (1100) for identifying a particular coded communication signal (301) from received coded communication signals (303, 305). The receiver (900) comprises a memory device (905) and a processor (907). The memory device (905) stores information contained in the received coded communication signals (303, 305) during multiple modulation symbol time intervals (210) to produce stored information. The processor (907) then searches the stored information to identify the particular coded communication signal (301).

Abstract: A method and apparatus is provided for combining a plurality of signals in a digital pipelined signal adder. The method includes the steps of receiving (100) an upstream primary signal in a combiner and error checking 101 the primary signal in the combiner. When the primary signal passes error checking the primary signal is selected (103) and when the primary signal fails error checking a redundant signal is selected (102). The method further includes adding (104) the selected signal and a local input of the plurality of signals within the combiner to produce a downstream primary signal.

Abstract: A method and apparatus is provided for facilitating scanning of radio control channels where a plurality of communication systems conjunctively cover the same area. A subscriber unit receives an overhead message train on a control channel which includes a channel count representing the number of control channels of a communication system. Subsequently, the subscriber unit scans a channel count number of control channels to tune to a control channel being used by a communication system having coverage for the subscriber unit. This scanning of control channels starts with a predetermined start control channel which corresponds to the logical number of the control channel in a sequence of control channels which is after the channel count control channel. In addition, an apparatus may be provided to transmit, in the overhead message train, a subscriber unit control message with an address indicating that a communication system is operating within a coverage area.

Abstract: The present invention provides an apparatus and method for locking the mobile identification number (MIN) of a mobile communication unit (22,24) at the mobile switching center (MSC) (18). Once a MIN is locked at the MSC, the cellular communication system (10) will block any mobile communication unit (22,24) attempting to originate a call with the locked MIN, even if it is the mobile communication unit (22) assigned the locked MIN which is attempting to place the call. The user may lock and unlock the mobile communication unit MIN from any public switch telephone (26), from selected public switch telephones, from the mobile communication unit (22) itself, from other mobile communication units (24). The mobile communication unit MIN may also be locked by default.

Abstract: A method (300) and apparatus (200) provide for determining when a digital packet data signal and a voice signal are being concomitantly transmitted on a voice channel of a communication system. A sample of the transmitted signal (110) is compared (310) to a pre-transmitted sample of the digital packet data signal (108). In response to the comparison, a digital packet data transceiver hops (314-320) from the first voice channel to a different voice channel for transmitting the digital packet data signal when voice signals are present.

Abstract: A method and apparatus for determining the location of a communication unit in a CDMA system includes in a first embodiment, sending a location request via a spread spectrum signal to the subscriber (140), and receiving in return a subscriber signal including a response message showing a receive time of a particular symbol of the base's spreading sequence and a transmit time of a particular symbol of the subscriber's spreading sequence. The base (130), along with other receiving base(s) (140), also receives a predetermined symbol of the subscriber spreading sequence, and each determines a respective receive time of the predetermined symbol. The received information is then processed, along with known base location and delay information, to determine the subscriber location. If insufficient number of bases are capable of communicating with the subscriber, for example due to high loading/interference, auxiliary bases (121) are also provided for receiving from or transmitting to the subscriber.

Abstract: A feed forward amplifier network (100) employs a method (300) and apparatus for reducing distortion contained in an output signal (142) of an amplifier circuit (101). A modulator (118, 120) modulates (303) an input signal (141) of the amplifier circuit (101) with a reference modulation. The amplifier circuit (101) amplifies (305) the modulated signal, introducing nonlinear distortion in the process. A modulation determination circuit (107, 109, 115) determines (307) the reference modulation in the amplified signal and provides the determined modulation to an adjustment circuit (105). The adjustment circuit (131,133, 135) adjusts (309) a characteristic of the determined modulation in response to a control signal (153,155) and combines (137, 311) the adjusted modulation with the amplified signal (142) at the output of the amplifier circuit (101) to produce a corrected signal (151).

Abstract: A new frequency plan is allocated in a communication system by first comparing (30) the channels in the old frequency plan with the channels in the new frequency plan to identify any problem channels that may exist (31). The system then attempts to clear any problem channels by reassigning (14) mobile stations, that may be currently assigned to those problem channels, to channels common to the old and new frequency plans, first non-problem channels. The new frequency plan is then implemented (15) by activating any new channels that are not active under the old frequency plan and deactivating any old channels that are not a part of the new frequency plan and are not currently assigned. Any remaining mobile stations still assigned to problem channels are then reassigned (17) within the new frequency plan and the problem channels are then de-allocated.

Abstract: A system and method for locating a portable locator device in a communications network. The portable locator unit (PLU) (4) is activated either by an external signal (62) generated in response to remote activation source, such as a subscriber (6, 8) or PLU detector (106, 108), or by an internal activation signal triggered e.g. by the wearer. Once activated, the PLU (4) transmits a location signal (66). This location signal (66) is received by one or more network service nodes (20, 22, 24) which forward the information along with identifying service node information to a network location processor (26, 28). After having determined the location of the PLU (4) from the received information, the network location processor (26, 28) forwards this information to a designated source, such as the requesting subscriber or other authorized user (6, 8).

Abstract: A communication system (100) employs a method of messaging between a subscriber unit (105) and an infrastructure communication center (101). A messaging key associated with a subscriber unit reference number is provided (203, 403) to the subscriber unit (105) and to the infrastructure communication center (101). An authentication key and/or an identifier for the subscriber unit (105) is then produced (300, 407) by either the subscriber unit (105) or the infrastructure communication center (101). The authentication key and/or the identifier is encrypted (207, 413) with the messaging key and is subsequently communicated (209, 415) between the subscriber unit (105) and the infrastructure communication center (101).