Abstract: An FM demodulator compensates for DC offset by detecting the positive peak value of the frequency demodulated signal (D1, C2, R1) and the negative peak value of the frequency demodulated signal (D2, C3, R2). The mean of the positive and negative peak values is determined (C1, R3, R4) to produce an estimation of a DC offset value. This estimated DC offset value is then used to compensate for DC offset in the frequency demodulated signal. This circuit has the advantage of enabling the DC offset to be calculated without requiring complex digital signalling processing, and without requiring the input signal to have a zero mean. A signal strength signal RSSI may be used to disconnect the DC offset compensation circuitry during periods when the input signal strength is weak.

Abstract: An FM demodulator compensates for DC offset by detecting the positive peak value of the frequency demodulated signal (D1, C2, R1) and the negative peak value of the frequency demodulated signal (D2, C3, R2). The mean of the positive and negative peak values is determined (C1, R3 , R4) to produce an estimation of a DC offset value. This estimated DC offset value is then used to compensate for DC offset in the frequency demodulated signal. This circuit has the advantage of enabling the DC offset to be calculated without requiring complex digital signalling processing, and without requiring the input signal to have a zero mean. A signal strength signal RSSI may be used to disconnect the DC offset compensation circuitry during periods when the input signal strength is weak.

Abstract: A method and apparatus for token distribution include providing one or more nodes of a plurality of network nodes with a token machine that includes counters associated with each of other network nodes having a token machine. Each time a token possessing network node implicitly or explicitly passes the token to another network node having a token machine, counter values of each of the counters associated with each node having a token machine are adjusted. When a token is passed, the counter value of the receiving node is adjusted based, at least in part, on an initial token interval value, and counter values associated with other nodes are adjusted toward a threshold value. The decision as to where the token is passed may be based, at least in part, on the value of a counter and/or an assigned counter priority level.

Abstract: One of a number, n, of slave devices is selected for express or implicit polling by a master device in a communication system that transmits during individual ones of a number of sequentially occurring time slots. This is done by assigning a corresponding priority level to each slave device, wherein at least two slave devices are assigned different corresponding priority levels. A corresponding count parameter and a corresponding initial count value are assigned to each of the slave devices. For each of the slave devices, the corresponding count parameter is initialized to the corresponding initial count value. For each successive time slot, each of the count parameters is adjusted (e.g., by decrementing). A highest priority slave device whose corresponding count parameter has reached or passed a predetermined value is selected for polling.

Abstract: An uncoordinated frequency hopping cellular system includes a mobile unit and a number of base stations. The mobile unit determines which base stations are in a geographical location defined by a location of the mobile unit. This determination is made by transmitting one or more inquiry messages, and receiving response information transmitted by responding base stations. The mobile unit then selects, for use by the mobile unit, one of the base stations from the set of base stations. Each of the base stations receives at least one of the inquiry messages, and transmits the response information to the mobile unit in response to the at least one received inquiry message. The mobile unit determines synchronization information from the response information, and uses this to establish communication with the selected base station.

Abstract: A system and a method to automatically select a frequency set in a low-tier radio communication system, sharing frequencies with an overlapping high-tier cellular radio system, that minimally interferes with the high-tier system employing frequency hopping is described. The present invention makes use of the broadcast information that is transmitted by the high-tier radio base stations on their broadcast control channels (BCCH), which contains not only the BCCH carrier frequencies of surrounding cells, but also information regarding the frequencies applied in the considered cell for frequency hopping traffic channels. With this broadcast information, the low-tier system can derive the frequency planning of the high-tier system, and can then derive a frequency set for low-tier usage that minimally interferes with the overlapping high-tier system.

Abstract: A step size is generated for use in a continuous variable slope delta (CVSD) demodulator by determining a likelihood that a group of one or more coded bits includes an erroneous bit. The step size is then generated as a function of the likelihood that the group of one or more coded bits includes an erroneous bit. For example, if the CVSD demodulator requires that the step size be increased, then the step size is increased by a larger amount if the likelihood of error is not greater than a threshold likelihood, and the step size is increased by a lesser amount if the likelihood of error is greater than the threshold likelihood.

Abstract: A method of and a system for radio communication in a Time Division Multiple Access (TDMA) radio communication system, wherein a communication channel includes at least one time slot of a plurality of sequential time slots forming a TDMA frame, and wherein a time slot of a frame hops in position between sequential frames. The hopping of a time slot depends on the type of information transmitted in the time slot.

Abstract: Establishing a connection between a paging unit and a standby unit in a channel hopping communications system includes activating the standby unit for an activation time period out of every standby time period. During each activation time period, the standby unit monitors a selected channel for receipt of a paging message. The selected channel is selected from a plurality of channels, and, for each subsequent activation time period, the selected channel is a subsequent one of the plurality of channels as specified by a hopping sequence and an internal clock. A page train is repeatedly transmitted from the paging unit to the standby unit, until a response is received from the standby unit. Each page train includes a plurality of paging messages, each paging message being transmitted on a different one of a subset of the plurality of channels. Selection of a page train for transmission by the paging unit may be based on an estimate of the standby unit's internal clock.

Abstract: An allocation method and system for allocating a least-interfered communications link between a cellular mobile station and a private radio base station within a cellular system is disclosed. A set of candidate carrier frequencies are first selected and ordered by the amount of interference present within the cellular system, and a subset thereof selected. A second set of candidate frequencies and associated timeslots are then selected from the subset and ordered by the amount of interference present in the private radio system environment, and a second subset thereof selected. A plurality of discrete hop lists for each timeslot are then formed, and one of the hop lists exhibiting the least amount of interference is then selected to be applied in the communications link.

Abstract: A data and message retrieval communications system utilizes a base station such as a PC or cellular phone to transmit received messages and stored data in accordance with an operator customized data configuration and transmission scheme. The system includes a remote receive-only communication unit that receives and processes the signal from the base station in accordance with an operator customized data configuration and retrieval scheme. The remote unit preferably includes a receiver having an antenna, a processor that processes the transmission signal received by the receiver, a memory storing the personal data and data corresponding to the transmission signal, and a display interface unit enabling an operator to interface with the processor programmed to access and control the receiver, the memory and the display interface in accordance with the operator customized data configuration and retrieval scheme. In one arrangement, the remote communication unit is embodied in a wristwatch for maximum portability.

Abstract: In a multi-reuse level cellular communications system, a channel is assigned for use by a mobile unit by first determining whether the mobile unit is a non-enhanced mobile unit or an enhanced mobile unit. Then a determination is made as to the type of communication service being requested. A minimum link quality required by the mobile unit can then be established based on factors that include the mobile unit type and the type of communication service being requested. A base station that has the necessary receiver detection capabilities and transceiver processing capabilities is then selected, and a channel, corresponding to a highest reuse plan, available to the base station is assigned to the call.

Abstract: A system and method for allowing intercom and multiple voice channel communication within a private telephone system employing a private base station and a multiplicity of standard cellular terminals is disclosed. Full duplex intercom communications between two users within the private telephone system may be facilitated by use of two half-rate channels, one channel transceiver on even-numbered TDMA transmission frames and another channel transceiver on odd-numbered transmission frames, both from respective terminals to a private base station, which mediates the communication therebetween. Multiple voice channels are also provided within the private telephone system, allowing two users on two separate channels to communicate with respective remote wireline users simultaneously.

Abstract: A multi-channel Automatic Retransmission Query (ARQ) methods transmits data packets from a source to a destination over a communication link that is subdivided into a number of channels. A network using the multi-channel ARQ method sequentially multiplexes the data packets at the source and transmits them over corresponding channels. The network applies a stop-and wait ARQ method on each one of the channels and determines whether the destination has positively acknowledged a previously transmitted data packet. If not, the network retransmits only the data packets that are not positively acknowledged.

Abstract: An allocation method and system for allocating a least-interfered communications link between a cellular mobile station and a private radio base station within a cellular system is disclosed. A set of candidate carrier frequencies are first selected and ordered by the amount of interference present within the cellular system, and a subset thereof selected. A second set of candidate frequencies and associated timeslots are then selected from the subset and ordered by the amount of interference present in the private radio system environment, and a second subset thereof selected. A plurality of discrete hop lists for each timeslot are then formed, and one of the hop lists exhibiting the least amount of interference is then selected to be applied in the communications link.

Abstract: Establishing a connection between a paging unit and a standby unit in a channel hopping communications system includes activating the standby unit for an activation time period out of every standby time period. During each activation time period, the standby unit monitors a selected channel for receipt of a paging message. The selected channel is selected from a plurality of channels, and, for each subsequent activation time period, the selected channel is a subsequent one of the plurality of channels as specified by a hopping sequence and an internal clock. A page train is repeatedly transmitted from the paging unit to the standby unit, until a response is received from the standby unit. Each page train includes a plurality of paging messages, each paging message being transmitted on a different one of a subset of the plurality of channels. Selection of a page train for transmission by the paging unit may be based on an estimate of the standby unit's internal clock.

Abstract: An allocation method and system for allocating a least-interference communications channel between a cellular system and a private radio system within the cellular system. A set of candidate channels are first selected and ordered by the amount of interference present within the cellular system, and a subset thereof is selected. A second set of candidate channels are then selected from the subset and ordered by the amount of interference present in the private radio system environment, and a safe channel subset thereof is selected. That channel exhibiting the least amount of interference is then selected from the safe channel subset as the communications channel.

Abstract: If no uncorrectable errors are discovered in a received data packet, an acknowledgment is sent back to the sender. Conversely, if the data packet contains uncorrectable errors, no acknowledgment is sent, forcing a re-transmission of that data packet in accordance with an automatic repeat request (ARQ) procedure. In such cases, sets of unquantized signal values relating to received data packets having uncorrectable errors are stored. When two or more sets of unquantized signal values for the same received data packet (as re-transmitted) have been stored, the unquantized signal values are numerically combined on a bit-by-bit basis, and then quantized to regenerate a combined data packet. If no uncorrectable errors are discovered in that combined data packet, an acknowledgment is sent back to the sender. Otherwise, no acknowledgment is sent, forcing another data packet re-transmission.

Abstract: A private radio system within a serving cell of a cellular communications system periodically monitors the broadcast information transmitted on the control channels of the serving and surrounding cells. From this monitoring, all those carrier frequencies serving as control channels are derived for the cell areas around the serving cell and a control channel list constructed. The private radio system then carries out signal strength measurements on the downlink control channels, and orders the control channel list accordingly. Alternatively, a mobile station that is attached to a private radio system can perform the downlink measurements and forward the measurements to the private radio system.

Abstract: During handover of a cellular terminal from a wide area cellular network to a base station, authentication messages are relayed between the base station and the wide area cellular network via the cellular terminal. Communications between the cellular terminal and the wire telephone network via the base station are prevented until after authentication takes place. Accordingly, the cellular terminal relays authentication messages between the base station and the wide area cellular network. Use of the wire telephone network for authentication between the cellular terminal and the base station is avoided. Secure handover is thereby provided without incurring excess overhead to the system and without adding unnecessary wire network charges to the cellular terminal user.