Abstract: A method of providing communication services in a cellular communication system which consists of a plurality of service coverage areas having a plurality of shared frequency microcells. Each microcell has an omnidirectional, remote antenna interconnected with a base site. The method consists of receiving a request, at the base site, to provide communication access to a communication unit. A supervisory audio tone is simulcast through each omnidirectional, remote antenna of the plurality of shared frequency microcells. A signal quality factor of a looped-back supervisory audio tone received from the communication unit at each omnidirectional, remote antenna is then measured. A communication link between the communication unit and base site is then established through a selected antenna of said plurality of omnidirectional, remote antennas. The antenna is selected based upon the signal quality factor of the looped-back supervisory audio tone.

Abstract: A method and apparatus for establishing frequency assignments for a fixed radio communication unit of plural fixed radio communication units coupled via a controller. A controller functions to have the communication unit measure transmitted signal strengths, and to request the other fixed radio communication units to transmit at assigned frequencies. The system functions to identify and select one (or more) of the frequencies measured having the lowest signal strength and adjacent channel and/or co-channel interference characteristics beneath set threshold level(s). The system also operates to repeat the process for each fixed radio communication unit, until all are assigned frequencies.

Abstract: The power of a first signal is measured and is compared with a threshold. If the first signal power meets a handoff threshold, the system enters the handoff procedure. Once in the handoff procedure, estimates of a first signal quality a signal would have, if transmitted from the first site to the subscriber, and a second signal quality a signal would have, if transmitted from the second site to the subscriber, are determined. If the estimated first signal quality meets a transmit threshold, the first will activate a traffic signal to the subscriber. If the estimated first or second signal quality fails to meet the transmit threshold, the first or second, respectively, will terminate its traffic signal to the subscriber, but the transmission resources will remain dedicated to the subscriber. If the estimated first or second signal quality fails to meet the handoff threshold, the first or second, respectively, will discontinue serving the subscriber.

Abstract: A method and apparatus are provided for echo canceling which includes double-talk immunity. The echo canceller (15) according to the present invention includes a double-talk detector (17) which uses an adaptive double-talk detection threshold (214) and an accurate estimation of reference energy (106) to detect double-talk. The echo canceller further provides for correcting partial echo canceller adaptive filter vector divergence occurring prior to double-talk detection by maintaining and switching to an auxiliary echo canceller filter with known "good" filter coefficients (58, 60, 62).

Abstract: One of two antennas (11, 12) is selected (34) by comparing the quality of a first signal (32) preceding a desired signal, received through a first antenna (11), with the quality of a second signal (33) preceding the desired signal, received through the second antenna (12), if the accuracy (62) of a previous desired signal was bad. If the accuracy of the previous desired signal was good (62), but the quality failed to meet a threshold (52), then an antenna (11, 12) is selected (65) by comparing the quality (63) of the first signal preceding said desired signal received through the first antenna (11) with the quality (64) of the first signal preceding the desired signal received through the second antenna (12). If the accuracy of the previous desired signal was good (62) and the quality met the threshold (52), then the first antenna (11) is selected (53).

Abstract: Signaling is inserted (102) into a communication channel of a communication system by inserting the signaling into the communication channel if the communication channel has sufficient available bandwidth (104). If the communication channel does not have sufficient available bandwidth, reducing the bandwidth of information being communicated on the communication channel (106) and inserting the signaling into the communication channel (108) with reduced information bandwidth.

Abstract: A received signal is provided to an automatic gain controller which normalizes the received signal to a known voltage level. The automatic gain controller is also provided with an OUNS noise signal through a voltage controlled attenuator. The voltage controlled attenuator (VCA) is controlled by an OUNS controller such that the output of the VCA represents the desired other user noise level to be combined with the received signal in the automatic gain controller.

Abstract: In a TDM readiotelephone network, there is provided a mechanism for introducing link asymmetry between an uplink and a downlink, paired frame alternation on the uplink and downlink and bandwidth multiplexing/sharing/apportionment within and among successive frames. The result is increased interleaving depth and a reduction in round-trip delay from the traditional half-rate speech coding approaches.

Abstract: A digital oscillator is synchronized to a master clock by comparing the master clock to an output of the digital oscillator by providing both to a first register which enables a counter. The counter increments while enabled until cleared. The output of the counter is then compared with a stored signal. Depending upon the match with the stored signal, the output of the digital oscillator is either slowed, advanced or maintained. The output from the digital oscillator is then fed back to an input of the digital phase locked loop.

Abstract: Transmission is controlled using the present method after a handoff procedure has been entered between a subscriber unit and target transceivers. During this process, a communication link between the subscriber and at least one other transceiver is maintained. A quality factor of a signal from the subscriber is received by the target transceiver. If the quality factor meets a quality threshold, then a transmission from the target transceiver is activated. If the target transceiver is active and the quality factor drops below the quality threshold, then the transmission from the target transceiver is terminated.

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: The transmit power margin of frame error rate for each subscriber in the system is measured to determine if any "bad" subscribers, those subscribers with transmit power margins of frame error rates that cross a threshold, are in the system. If the system is under capacity, the threshold level is set to the first threshold and the signal-to-noise ratio is incremented. If the system is at marginal capacity, the threshold transmit power margin is set to a second threshold and the system is closed to new calls. If the system is over capacity: the threshold transmit power margin is set to a second threshold; the system is closed to new calls; and the signal-to-noise ratio is decremented.

Abstract: Mobility is provided for wireless local loop radiotelephone systems by providing the home access network of a subscriber unit with a home access number. Upon registration of the subscriber unit with its home access network, the home access number is transmitted to the subscriber unit for storage there. When the subscriber unit moves to a visited access network and registers there, the subscriber unit transmits the home access number to the visited access network, which uses the home access number to contact the home access network. Since all call originations and terminations by and to the subscriber unit occur via the individual subscriber line appearance at the PSTN, a minimum of special network elements are required for subscriber unit mobility when the home access number is stored at the subscriber unit.

Abstract: Radio frequency reuse between two or more radio frequency communications systems is facilitated by having a beacon transmitter broadcast information globally throughout an area, which information identifies to users of a second system, which radio frequency resources are already in use by a first communications system. The global broadcast of information as to what channels are in use, permits users in the second system to avoid interfering use of those frequencies.

Abstract: Base Station Transceiver Equipment 10 is provided such as for use in a cellular radio telephone system. In a first aspect of the invention, a device within the equipment measures a parameter (e.g. timing, signal strength) of a mobile transceiver and instructs the mobile to adjust that parameter of its transmitted signals. Subsidiary transceiver equipment 11 (a diagnostic sub-system or "test mobile") is provided in relative proximity to the base station transceiver equipment. The subsidiary equipment can change the parameter of its transmissions to simulate relative distance from the base station transceiver equipment for test purposes. In other aspects of the invention, a device is provided for testing the base station antenna.

Abstract: An electrical circuit (200) having an input terminal (201), an output terminal (202), and a signal common (203) is preferably used to attenuate an electrical signal. The electrical circuit (200) comprises four impedance elements (205-208) and an impedance transformer (210). A first impedance element (205) is coupled between the input terminal (201) and a first node (212), while a second impedance element (206) is coupled between the first node (212) and the output terminal (202). A third impedance element (207) is coupled between the input terminal (201) and the output terminal (202), while a fourth impedance element (208) is coupled between a second node (213) and the signal common (203). The impedance transformer (210) is coupled between the first node (212) and the second node (213) to complete the electrical circuit (200).

Abstract: A coherent RAKE receiver utilizes a "blind block" path gain estimation scheme, based on a maximum likelihood criterion, to estimate path gains in the receiver. It is "blind" in that preliminary hard decisions on coded bits (i.e., coded bits from the corrupt transmitted signal) are not used. Instead, a form of soft decisions are used. It is a "block" scheme in that the complex path gains are estimated for an isolated block, for example a block of B correlator outputs. The path gains varying with time are approximated to be linear in time such that the average path gain and the slope of the path gain per path can be utilized to estimate the path gain. The path gain estimation scheme overcomes the shortcomings of typical CDMA systems where there is no assurance of continuous transmission (except for full-rate 9600 b/s transmission) upon which to base a FIR filter-type prediction scheme.

Abstract: A transcoder is described for performing transcoding operations, that is to say coding and decoding operations on voice data arranged over a plurality of voice data channels. It comprises a first interface (10) for inputting and outputting coded voice data, a second interface (11) for inputting and outputting decoded voice data; at least one transcoder processor (101) for performing transcoding operations on voice data arranged over at least two voice data channels; and an input/output processor (100) coupled to the first and second interfaces and the at least one transcoder processor for controlling the flow of data between the first and second interfaces and the at least one transcoder processor. The input/output processors controls the at least one transcoder processor to perform transcoding operations on a selected channel at a given time. The invention is particularly applicable to transcoding between CEPT standard voice data and GSM standard voice data.

Abstract: In a cellular communication system, the delivery of a page or message is attempted over the system to a user of the system. If the page or message is undeliverable before a set period of time, the page or message is converted to a voice mail message. The voice mail message is then stored in the cellular communication system. When the cellular communication system is accessed by the user, the user is notified of the existence of voice mail by either a text page or an automated voice radiotelephone call. The stored voice mail message is then delivered either automatically, or at the user's request.