Abstract: A method and corresponding apparatus for re-establishing a communication in a wireless communication system is disclosed. A serving base-station (32) detects that a synchronization with a mobile station (38) has been lost and chooses a target base-station (34) to attempt to establish synchronization with the mobile station (38). If synchronization is established, the communication with the mobile station (38) is re-established by the target base-station (34). The method and corresponding apparatus does not require any handoff-related signaling to the mobile station (38) to essentially effect a communication handoff from the serving base-station (32) to the target base-station (34).

Abstract: In a wireless communication system, including a first fixed communication unit (105), a plurality of other fixed communication units (101, 106), and a mobile communication unit (103) responsive to at least the first fixed communication unit, a radio telephone service planning method for generating a handover neighbor list. The method includes determining a route of travel of the mobile communication unit (103) relative to the first fixed communication unit (105). The method also includes establishing a plurality of connections between the mobile communication unit (103) and the plurality of other fixed communication units, based on the route of travel of the mobile communication unit, and then determining a corresponding plurality of signal quality metrics for the plurality of connections. The method further includes generating a handover neighbor list based on the corresponding signal quality metrics.

Abstract: A wireless communication system, including a first fixed communication unit and a second fixed communication unit, a mobile communication unit responsive to the first fixed communication unit and the second fixed communication unit, a method for transferring a communication signal associated with the mobile communication unit from the first fixed communication unit to the second fixed communication unit, the method comprising the steps of establishing the communication signal between the first fixed communication unit and the mobile communication unit; and sending a list to the mobile communication unit, the list comprising a reserved traffic channel associated with the second fixed communication unit, the mobile communication unit establishing communication with the second fixed communication unit over the reserved traffic channel when the communication signal is interrupted.

Abstract: A method of maintaining call quality in a communication system by communicating between a base site (101) and a communication unit (113) on a first channel. The communication unit (113) monitors the downlink communication signal (116) transmitted by the base site (101) and determines a characteristic of the first channel. The communication unit (113) is then handed off to a second channel having a less aggressive reuse pattern, based on the characteristic of the first channel.

Abstract: A visual presentation of a simulated communication unit moving through a wireless communication system is combined with an audio presentation of speech that a user would hear (311) if the user were placed in the same radio environment. In addition, both audible and visual indicia of RF interference may also be provided (107, 109), with or without audio playback, to aid in designing around interference sources and their intensities. A set of error masks and corresponding audio files are created (305), wherein each file contains the same audio track, but based on speech error masks created at different vehicle speeds and signal to noise ranges. Real-time playback of the audible signal with noise is useful in planning for particular needs of a wireless communication system planner.

Abstract: A base site (100) employs a method and apparatus for selecting two of a plurality of antennas (101-106) from which to receive a communication signal. A first signal quality metric is measured for a communication signal received from a first antenna (102) and a second signal quality metric is measured for the communication signal received from a second antenna (103). When the first signal quality metric differs from the second signal quality metric by a threshold, a signal receiver (113) is coupled to a third antenna (e.g., 101) and a third signal quality metric is measured for the communication signal received from the third antenna (101). Based on the three signal quality metrics, a primary antenna and a secondary antenna are selected from which to receive the communication signal.

Abstract: A method including the steps of performing a synchronization measurement of a received signal (102), and performing a handoff (110) between a first communication channel and a second communication channel in response to the synchronization measurement. An apparatus including a receiver (50) detecting a received signal over a first communication channel, a receive signal processor (44) responsive to the receiver (50), and a handover controller (40) responsive to the receive signal processor (44). The receive signal processor performs a synchronization measurement of the received signal. The handover controller (40) initiates a handoff between the first communication channel and a second communication channel in response to the synchronization measurement.

Abstract: A smart card (100) is equipped with an internal time-of-day clock and calendar (106). Between the smart card (100) and a subscriber unit (209, 300), into which it is inserted, there is a communication of the subscriber's identity and a negotiated agreement for how long the subscriber unit (209, 300) is to maintain the transferred identity. For that duration of time, the subscriber unit (209, 300) is enabled with the subscriber's identity, and the smart card is essentially "dumb," and therefore unusable until that duration has elapsed.

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 of reducing an audio gap in a signal connection with a communication unit during handoff in a cellular communication system is provided. The method includes the steps of providing a temporary signal connection with the communication unit from a mobile switching center (MSC) of a source base site, through the source base site to a handoff target base site and establishing a trunk connection from the MSC of the source base site to a MSC of the target base site. The method further includes the step of interconnecting, at the target base site, the temporary signal connection, trunk connection, and communication unit; and re-routing the signal connection with the communication unit through the trunk connection.

Abstract: The method consists of analyzing a handoff request received from a source base station at a source base site controller (BSC). If the handoff request contains a preferred base site list (is from a MAHO environment) the request is forwarded to the mobile switching center. If the handoff request does not contain the preferred list, the BSC generates a candidate list and transmits measurement messages to each candidate base site. The candidate base sites take measurements and reply to the BSC. The BSC uses the replies to generate a preferred base site list which is forwarded to the MSC. When the MSC receives a preferred base site list, it selects a handoff base site and executes the handoff.

Abstract: A method of reducing an audio gap in a signal connection with a communication unit during handoff in a cellular communication system is provided. The method includes the steps of providing a temporary signal connection with the communication unit from a mobile switching center (MSC) of a source base site, through the source base site to a handoff target base site and establishing a trunk connection from the MSC of the source base site to a MSC of the target base site. The method further includes the step of interconnecting, at the target base site, the temporary signal connection, trunk connection, and communication unit; and re-routing the signal connection with the communication unit through the trunk connection.

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: 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: A system and method of evaluating the radio coverage of a geographic area serviced by a digital cellular radiotelephone communication system is described which comprises a plurality of base stations each having a transmitter and a receiver and a plurality of mobile units having co-located transmitters and receivers for transmitting and receiving communication message signals between the base stations and a mobile unit. During operation, the position of at least one of the mobile units operating within the geographic area is located when a call is received by a base station. The base station monitors the signal quality of the call and collects information relevant to the actual performance of the communication system.

Abstract: A system and method of evaluating the radio coverage of a geographic area serviced by a digital cellular radiotelephone communication system is described which comprises a plurality of base stations each having a transmitter and a receiver and a plurality of mobile units having co-located transmitters and receivers for transmitting and receiving communication message signals between the base stations and a mobile unit. During operation, the position of at least one of the mobile units operating within the geographic area is located when a call is received by a base station. The base station monitors the signal quality of the call and collects information relevant to the actual performance of the communication system.

Abstract: A cellular radiotelephone system (101) includes a control terminal (420) coupled by in trunks and out trunks to the telephone central office (110) and by data and voice lines to base sites (411-416) in corresponding cells (401-406) for providing telephone coverage to mobiles located throughout a geographical area. In order accommodate additional voice channels in each cell (401-405), base sites (441-446) are colocated with corresponding existing base sites (401-405). Paging/access channels are assigned to existing base sites (411-416) for paging mobiles for all outgoing originations and processing all incoming mobile originations and page responses. Access-only channels are assigned to colocated base sites (441-446) for processing mobile originations and page responses transferred thereto by a directed retry message from corresponding existing base sites (401-405).

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: A two way radio system employing power control of a remote station transmitter to produce a predetermined received signal level at a fixed site after handoff of the remote station from one radio channel to another is disclosed. A signal strength measurement is made on the in-use channel and a power level for the remote station transmitter is calculated from the measured signal strength, a predetermined nominal signal strength desired on the target radio channel, and a linear correlation of signal strength and remote station power level steps. The calculated remote station power level is then transmitted to the remote station as part of a handoff command.