Abstract: In a cellular radio-telephone system (50), a method of selecting an appropriate handoff target where the timing advance of a mobile has exceeded a timing advance threshold, the bit error rate has risen above a BER theshold, or the signal level has fallen below an RSSI threshold. The method includes discarding signal measurements of inappropriate base sites or base sites at excessive distance and performing calculations on the remaining measurements to select an appropriate handoff target.

Abstract: A method of selecting handover targets for a communication unit exchanging a communicated signal through a serving base site in a digital cellular system. The method uses timing advance to determine a relative distance of a communication unit to the serving base site. The method comprising the steps of comparing a timing advance value with a first threshold. The first threshold may be equal to a distance one and one-half times the radius of the serving cell. When the timing advance value exceeds the first threshold, a base site frequency list is modified to include base sites non-adjacent the serving base site. The identity of the non-adjacent base sites may be determined from the directionality of the communication unit. The method further includes the step of selecting a handover target providing a highest relative RSSI value to the communication unit from the modified base site frequency list.

Abstract: An AMPS system facilitates reception and processing of a DS CDMA signal transmitted by a mobile station (125). The AMPS system provides an alternate path for the signal to be received by a DS CDMA receiver (506) system. The DS CDMA receiver system generates a signal compatible with the AMPS system, adjusts the generated signal to be proportional to the DS CDMA signal, and inputs the adjusted signal (510) into the AMPS system. The AMPS system then processes the adjusted signal for purposes of handoff of the mobile station (125) from the DS CDMA system to the AMPS system.

Abstract: A method is offered of achieving a desired C/I ratio within a cellular system, at reduced transmitter power levels, by measuring a signal loss on a downlink between a base site transmitter (31) and mobile receiver (20) and calculating an uplink signal magnitude at a base site receiver. A communication channel is then selected from a number of communication channels based upon comparison of the uplink signal magnitude with pre-measured interference levels for each channel of the number of channels to produce a desired C/I ratio.

Abstract: The method of conveying control and program information between cellular radiotelephone controllers and of detecting information errors is disclosed. When a program memory information error is detected, a predetermined amount of memory information is conveyed from a first controller to a second controller. If a comparison of checksums of a predetermined amount of memory information stored at the second controller and the memory information received from the first controller matches, additional memory information is conveyed. If a match is not found, the predetermined amount of memory information is reconveyed from the first controller to the second controller.

Abstract: A cellular radiotelephone system providing service to remote units having a voice operated transmitter (VOX) is disclosed. If the regularly scheduled periodic signal quality measurements made by fixed site equipment indicate that the remote unit signal has not been received for a predetermined number of measurements, an audit request is transmitted to the remote unit. The remote unit responsively keys its transmitter for a predetermined period of time. A first special scan is programmed into the regular process such that the fixed site equipment may continue with its regular process until the signal quality measurement must be made. A second measurement is made following the first and if the two signal quality measurements made while the VOX remote unit is known to be transmitting agree, system reconfiguration for the service of this remote unit may be implemented by the cellular system.

Abstract: The method and apparatus for interfacing between a cell site controller, a cell system controller, and the radio transceivers of a cellular radiotelephone system is disclosed. To convey control information to the radio transceivers, the cell site controller enables one of a redundant pair of control data buses to a selected transceiver by placing an enable signal on the enable line unique to the selected transceiver. Control data is then coupled to the common enabled control data bus for conveyance to the selected transceiver. The transceiver mutes the message data port it may be using and transponds the control data information it receives. When the enable signal is removed, the transceiver unmutes the message data port. Program information is transferred between the cell system controller and cell site controllers as memory blocks which may be retransferred upon detection of a checksum mismatch.

Abstract: A method and apparatus for utilizing voice channel transceivers as temporary scanning receivers in a handoff event for a cellular radiotelephone system is disclosed. Voice channel transceiver identifications are stored in link lists according to priority, sectorization, and last use. When a signal strength measurement is required, those cell sectors having available voice channel transceivers are identified and a table providing optimum transceiver selection is utilized to select those voice channel transceivers which will make the signal strength measurement.

Abstract: A method and apparatus for determining which sector antenna of a sectorized cellular radiotelephone system is receiving the strongest radio signal is disclosed. The signal strength of sector antennas is sequentially sampled, converted to digital representations, and stored according to which antenna received the signal. The digital representations are recalled from storage and the strongest signal along with an identification of the receiving antenna are determined. This determination may be used in the handoff process or in detecting when a remote unit requires a handoff.

Abstract: A fixed site station for cellular systems is disclosed. A plurality of radio transceivers are removably disposed in apertures of the common equipment housing and are provided unique parameters of operation by the system controller dependent upon the aperture in which the transceiver is located and the antenna configuration of the cell being served.