Abstract: A receiver comprising a sigma-delta analog-to-digital converter (.SIGMA..DELTA. ADC) can be utilized in one of four configurations, as a subsampling bandpass receiver, a subsampling baseband receiver, a Nyquist sampling bandpass receiver, or a Nyquist sampling baseband receiver. For subsampling .SIGMA..DELTA. receivers, the sampling frequency is less than twice the center frequency of the input signal into the .SIGMA..DELTA. ADC. For Nyquist sampling .SIGMA..DELTA. receivers, the sampling frequency is at least twice the highest frequency of the input signal into the .SIGMA..DELTA. ADC. For baseband .SIGMA..DELTA. receivers, the center frequency of the output signal from the .SIGMA..DELTA. ADC is approximately zero or DC. For bandpass .SIGMA..DELTA. receivers, the center frequency of the output signal from the .SIGMA..DELTA. ADC is greater than zero.

Abstract: In a concatenated code data, correctly decoded code words from a block decoder is utilized to improve the performance of the convolutional decoder. A code word can sometimes be correctly decoded prior to receipt of all the symbols for the code word. Early decoding of the code word allows for the correct recreation of the entire code word, even the symbols which have not yet been received. The entire corrected code word is used by the convolutional decoder to eliminate branches the trellis, thus improving decoding of prior data bits and future data bits in the trellis. The chain back distance of the convolutional decoder can also be made shorter based on the knowledge that some of the received code words have been correctly decoded. Finally, the parity symbols which have not yet been received for the correctly decoded code word can be eliminated from transmission to improve the overall transmission rate.

Abstract: In a code division multiple access (CDMA) spread spectrum cellular communication system in which a mobile station user communicates with another system user via at least one base station, wherein each base station transmits a common pilot signal of a different PN offset with respect to other base stations in said system, a method for merging neighbor lists to account for false indications of signal strength due to topography. The merged list, included as part of the Neighbor List Update Message, is arrived at by first measuring pilot signal strengths and phase delays received by the mobile station and reporting this information to the mobile telephone switching office. At the mobile telephone switching office, pilots whose phase delay indicates a large round trip delay time are ignored in subsequent calculations. Then a neighbor list union is generated as the union of all predetermined neighbor lists corresponding to said received pilot signals.

Abstract: A voice recognition system having a feature extraction apparatus is located in a remote station. The feature extraction apparatus extracts features from an input speech frame and then provides the extracted features to a central processing station. In the central processing station, the features are provided to a word decoder which determines the syntax of the input speech frame.

Abstract: A system and method for communicating information signals using spread spectrum communication techniques. PN sequences are constructed that provide orthogonality between the users so that mutual interference will be reduced, allowing higher capacity and better link performance. With orthogonal PN codes, the cross-correlation is zero over a predetermined time interval, resulting in no interference between the orthogonal codes, provided only that the code time frames are time aligned with each other. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. In the cell-to-mobile link, pilot, sync, paging and voice channels are defined. Information communicated on the cell-to-mobile link channels are, in general, encoded, interleaved, bi-phase shift key (BPSK) modulated with orthogonal covering of each BPSK symbol along with quadrature phase shift key (QPSK) spreading of the covered symbols.

Abstract: An L-shaped assembly fixture is used in connecting cables between components in a housing and a top panel for closing the housing after assembly. A base plate of the fixture has opposite side edges and opposite end edges, and an upright plate is secured along one side edge of the base plate so as to project upwardly in a direction perpendicular to the base plate. The upright plate has an upper edge with a slot extending along the length of the upper edge for supporting a top panel vertically adjacent an open face of a housing which is supported on the base plate.

Abstract: A method and apparatus for the selection of an encoding mode for speech frames in a variable rate encoding system. For each speech frame, the method and apparatus selects the encoding mode which provides for rate efficient coding. A mode measurement element receives a speech signal and a signal derived from the same speech signal, and generates a set of parameters which are ideally suited for operational mode selection. Rate determination logic receives the set of parameters and selects an encoding rate using predetermined selection rules. The selection rules further distinguish between unvoiced speech and temporally masked speech, which are encoded at the same rate but with different encoding strategies.

Abstract: A support fixture for supporting a face plate and CCA board as they are secured together has a base plate and a pair of end supports or blocks projecting upwardly from opposite ends of the base plate to support opposite ends of the face plate. A center support also projects upwardly from the base plate at a location spaced centrally between the two end supports for supporting a central region of the face plate. The end supports have rectangular recesses at the same height as the center support for receiving the opposite ends of the face plate. The height of the recesses and center support is selected to be greater than the height of any LED projecting from the CCA board through openings in the face plate, such that any such LED is spaced above the base plate.

Abstract: A method for handoff of an analog connection within a cellular communication system which relies upon mobile station synchronization to a system time is disclosed herein. In order to reduce the acquisition time for a mobile station commencing operation in a digital mode, an estimate of master system time is transferred to the mobile station in analog mode before entering digital mode. The alignment operates within the protocols of existing analog systems, and hence requires only minimal changes in the mobile station. Time alignment may be initiated upon the base station sending to the mobile station a command to continually transmit a periodic signaling tone. The base station compares the phase of the signaling tone from the mobile station to a master system clock and determines an error signal. The base station notifies the mobile station to delay or advance in time the transmitted signaling tones based on the error signal.

Abstract: The finite impulse response (FIR) filter is implemented as a table using read-only memory (ROM). The FIR filter table stores a pre-calculated output filter value for each permissible combination of input values to be filtered. Streams of input values are successively shifted into the table and corresponding output values are successively output. In an exemplary implementation, the FIR filter is employed within a digital cellular telephone for use in smoothing a digital signal to be transmitted. The size of the required FIR filter table is minimized by exploiting constraints imposed upon the signal to be filtered and by exploiting linearity and symmetry within the filter itself. More specifically, the telephone employs a data burst randomizer to provide a data signal composed of sequences of null or 0 values and sequences of antipodal values (+1's and -1's).

Abstract: A method and apparatus for providing a mobile station user with information about anticipated roaming charges. The visitor communication system transmits a graded roaming signal to the mobile station user indicative of the anticipated roaming costs. The graded roaming signal is determined by contractual agreements between the visitor communication system provider and user's service provider. This information is stored in a data base at the user's home communication system and is provided to the visitor communication system upon request for authorization to provide service. The graded roaming signal is broadcast to the mobile station and displayed to allow the mobile station user to estimate the cost of the service being provided.

Abstract: A method for determining the position of a mobile station within a cellular telephone system having a plurality of base stations. A signal is transmitted from a rotating antenna. The rotating antenna has a beam which rotates around a cell in the cellular telephone system. The beam has a rotational timing that is known by the mobile station. The signal is received at the mobile station. Based on a reception time when the signal is received by the mobile station, an angular displacement value corresponding to the position of the mobile station is determined. A first round trip signal propagation time between a stationary antenna and the mobile station is measured using a voice information signal. The position of the mobile station is determined in accordance with the angular displacement value and the first round trip signal propagation time.A method for determining the position of a mobile station within a cellular telephone system having a plurality of base stations.

Abstract: A method and apparatus are described for controlling the data rates for communications to and from a base station and a plurality of remote users. The usage of the communications resource whether the forward link resource (from base station to remote users) or reverse link resource (from remote users to base station) is measured. The measured usage value is compared against at least one predetermined threshold value and the data rates of communications or a subset of communications on said communications resource is modified in accordance with said comparisons.

Abstract: A method and apparatus for encoding and decoding QAM trellis modulated data. In the transmitter, a subset of bits of an input bit set are convolutionally encoded based upon a punctured convolutional code of a lower data rate to provide a set of coded symbols. The coded symbols and the uncoded bits of the input bit set are provided to a QAM modulator to provide a QAM modulation signal indicative of the values of coded symbols and the uncoded bits. In the receiver a QAM demodulator converts the received QAM signal to QAM signal space coordinates. A decoder employing the Viterbi algorithm is used to reconstruct a corrected estimate of the values of the coded data bits from the received signal coordinates. The corrected estimate of the values of the coded data bits are then used in conjunction with the received signal coordinates to provide corrected estimates of the values of the uncoded input bits.

Abstract: A method and apparatus for constructing high rate trellis codes for PSK modulation that can be encoded and decoded using the encoder and decoder for a rate 1/2 punctured convolutional code. In particular, the design of trellis encoders and decoders for 2.sup.k -PSK modulation for rates (km-1)/km for k.gtoreq.3 and m.gtoreq.1 is provided.

Abstract: To provide an unique call ID number in a system comprised of a plurality of entities through which a connection may be established, each entity through which a connection can be initiated is capable of assigning a unique number to a new connection. For example a first entity receives a first request to initiate a first connection and assigns a first unique number to said first connection. The first unique number comprises the identity of the first entity, a time at which the first request was received, a distinction of the first request from any other request received at the first entity in a time block during which said first request was received, and an indication of a system with which the first entity is associated.

Abstract: An apparatus for communicating variable rate data over a communication channel. A modulator that receive frames of user data each comprised of data symbols. The modulator repeats the data symbols within each frame to maintain a constant data rate. A transmitter receiver the modulator data and scales the modulated symbol data based upon the amount of symbol repetition in the frame.

Abstract: A method and apparatus for controlling transmission power in a variable rate communication system is disclosed. The method disclosed provides for a closed loop power control method. A first remote station controls the transmission power of a second remote station by transmitting a rate dependent power control signal to the second remote communication station. Since only the second communication knows its transmission rate a priori, it must determine its course of action in accordance with both the received power control signal and the knowledge of its transmission rate.

Abstract: A filter comprising a plurality resonator stages between sequentially coupled between input and output ports. The resonator stages are arranged such that at least one non-sequential pair of stages are physically adjacent. The non-sequential pair of resonator stages are separated by a common internal wall, which defines a bypass coupling aperture therebetween. During operation of the filter, attenuation poles are formed in the filter response due to bypass coupling between the non-sequential pair of resonator stages through the bypass coupling aperture. The preferred U-shaped arrangement of the resonator stages enables the formation of attenuation poles, without using an external bypass connection, by permitting inductive or capacitive bypass coupling through the bypass aperture.

Abstract: A novel and improved method of acquisition in a spread spectrum communication system is presented. In the present invention, a large window of PN chip offset hypotheses are searched and if an energy signal is found that might indicate the presence of the pilot signal having one of the chip offsets of the large search window, then a search of a subset of offset hypotheses, or small window, is searched.