Abstract: A system and method for encoding/decoding data channels in a CDMA system having data channel interference cancellation, wherein data channel interference cancellation is used to remove unwanted non-orthogonal pilot signal components which are present within a demodulated data signal. This is accomplished by regenerating interference terms with respect to the non-orthogonal pilot signal and subtracting them from the demodulated data signal.

Abstract: A transmitter includes a coupler (318) to measure output power. The output power is compared to a set value and a threshold. If the power is above the threshold, the gain of an output amplifier (316) is adjusted toward the set value. If the power is below the threshold, an extrapolation of the linear portion is used to obtain the set power level.

Abstract: A method of processing a sequence of digital symbols comprises the steps of processing the sequence of digital symbols and determining an uncertainty in the processing. If the uncertainty exceeds a predetermined threshold, then the method further comprises the steps of processing at least two sequences of digital symbols wherein at least one parameter is set differently in each sequence, and deciding upon a calculated error for each sequence which sequence is used to generate an output signal.

Abstract: Multiple field units in a CDMA system are synchronized for communication with a base station using shared forward and reverse link channels. In an illustrative embodiment, each field unit is assigned a time slot in a forward link channel to receive messages from the base station. Likewise, each field unit is assigned a time slot on a common reverse link channel for transmitting messages to the base station. Timing alignment and power level control among each of many field units and the base station is achieved by analyzing messages received at the base station in a corresponding time slot as transmitted by each field unit. Thereafter, a message is transmitted from the base station in a corresponding time slot to a particular field unit for adjusting its timing or power level so that future messages transmitted from the field unit are received in the appropriate time slot at the base station at a desired power level.

Abstract: A digital signal detector arrangement comprises at least two selectable baseband filters for receiving a digital signal, a signal estimator receiving the output signal of the selected baseband filter, a modulator unit receiving the estimated signal from the signal estimator, a subtractor for subtracting the modulated signal from the received digital signal, and a determination unit receiving the signal from the subtractor for selecting the baseband filter.

Abstract: Data rate allocation decisions are made for a communications channel, such as a wireless reverse link connection. A first parameter used in this determination is a path loss, which is determined by the following process. First, a message is sent from a first station to a second station, such as on a paging channel. The message indicates a forward Effective Radiated Power (ERP) of a pilot signal transmitted by the first station. The second station then determines the received signal strength of this pilot signal, taking into account receiver gains. The path loss can then be estimated by the second station as the difference between the forward ERP data value that it received and the detected received pilot power. The second station also then preferably determines a transmit power level when transmitting a message back to the first station. This transmit power level information is encoded as a digital data word together with the forward path loss information as calculated by the first station.

Abstract: Codes are applied to signals to reduce the number of transceivers and associated RF cabling extending from base electronics to antenna array electronics in a base station providing beam forming. The transceivers can be reduced to as few as one, and the RF cabling can be reduced to none. The codes may be orthogonal codes, such as Walsh codes. The codes are applied: to weights used to produce the beam forming, signal being transmitted or received, or both. The codes are applied a second time to decompose the coded weights/signal to associate the weights and signal with the beam forming. The coded weights/signal can be summed, including with other coded weights/signals, to produce a composite code division multiplexed signal for transmission between transceiver(s) and antenna array electronics over a single RF or non-RF cable spanning between the base electronics and array electronics.

Abstract: The present invention provides for making code rate adjustments and modulation type adjustments in a pseudonoise (PN) encoded CDMA system. Coding rate adjustments may be made by changing the number of information bits per symbol, or Forward Error Code (FEC) coding rate. A forward error correction (FEC) block size is maintained at a constant amount. Therefore, as the number of information bits per symbol are increased, an integer multiple of bits per epoch is always maintained. The scheme permits for a greater flexibility and selection of effective data rates providing information bit rates ranging from, for example, approximately 50 kilobits per second to over 5 mega bits per second (Mbps) in one preferred embodiment.

Abstract: A system and method for encoding/decoding data channels in a CDMA system having data channel interference cancellation, wherein data channel interference cancellation is used to remove unwanted non-orthogonal pilot signal components which are present within a demodulated data signal. This is accomplished by regenerating interference terms with respect to the non-orthogonal pilot signal and subtracting them from the demodulated data signal.

Abstract: A technique for efficient implementation of pilot signals on a reverse link in a wireless communication system. An access channel is defined for the reverse link such that within each frame, or epoch, a portion is dedicated to sending only pilot symbols. Another portion of the frame is reserved for sending mostly data symbols; however, within this second portion of the frame, additional pilot symbols are interleaved among the data symbols. The pilot symbol or preamble portion of the access channel frame allows for efficient acquisition of the access signal at the base station, while providing a timing reference for determining the effects of multipath fading. In particular, a pilot correlation filter provides a phase estimate from the pilot symbols in the preamble portion, which is then used to decode the data symbols in the payload portion. An access acquisition portion of the receiver uses the phase estimates provided by the pilot correlation filter to process the output of a data symbol correlation filter.

Abstract: An antenna assembly includes at least two active or main radiating omni-directional antenna elements arranged with at least one beam control or passive antenna element used as a reflector. The beam control antenna element(s) may have multiple reactance elements that can electrically terminate it to adjust the input or output beam pattern(s) produced by the combination of the active antenna elements and the beam control antenna element(s). More specifically, the beam control antenna element(s) may be coupled to different terminating reactances to change beam characteristics, such as the directivity and angular beamwidth. Processing may be employed to select which terminating reactance to use. Consequently, the radiator pattern of the antenna can be more easily directed towards a specific target receiver/transmitter, reduce signal-to-noise interference levels, and/or increase gain by using Radio Frequency (RF), Intermediate Frequency (IF), or baseband processing.

Abstract: A technique for a time division multiplex system in which access to shared broadcast communication media is granted on a demand basis. Particular connections are assigned slot times at the transmitter based on demand. However, no specific information regarding the assignment of time slots need be communicated to the receivers. The transmit side employs a forward error correction technique followed by multiplication by a cover sequence unique to each connection. All receivers listen to the broadcast transmission channel all of the time. The receiver assigned to each connection decodes the signals in such a manner that only the receiver with the correct cover sequence assigned to a particular connection will successfully decode the data associated with that connection. Data frames that fail the forward error correction process are discarded, and only those frames which are successfully decoded are passed up to a higher layer.

Abstract: A technique for encoding digital communication signals. Data symbols are augmented in pilot symbols inserted at predetermined positions. The pilot augmented sequence is then fed to a deterministic error correction block encoder, such as a turbo product coder, to output a coded sequence. The symbols in the error correction encoded sequence are then rearranged to ensure that the output symbols derived from input pilot symbols are located at regular, predetermined positions. As a result, channel encoding schemes can more easily be used which benefits from power of two length block sizes.

Abstract: A method of transmitting information between a transmitting station having an adaptive antenna array and a receiving station in a wireless communication system. The method includes the steps of generating default weight vectors for the antenna array of the transmitting station, transmitting the weight vector to the receiving station, modifying the weight vector in the receiving station, re-transmitting the modified weight vector to the transmitting station, and adapting the adaptive antenna array according to the modified weight vector within the transmitting station.

Abstract: A technique for encoding digital communication signals. Data symbols are augmented in pilot symbols inserted at predetermined positions. The pilot augmented sequence is then fed to a deterministic error correction block encoder, such as a turbo product coder, to output a coded sequence. The symbols in the error correction encoded sequence are then rearranged to ensure that the output symbols derived from input pilot symbols are located at regular, predetermined positions. As a result, channel encoding schemes can more easily be used which benefits from power of two length block sizes.

Abstract: A single, common correlation filter (CF) core is provided in a wireless system using CDMA. A plurality of channels with different data rates are provided in the wireless system. The channels provided in the wireless system include the access channel, the maintenance channel, and the traffic channel in which information (e.g., pilot or data symbols or both) is transmitted at the tier 1, tier 2 and tier 3 rates. The data rate for transmitting the information is programmable by digital signal processor (DSP). A user-unique code, such as a PN code, is applied to the information being transmitted in the channels of the wireless system. The information is QPSK modulated and transmitted in any one of the channels at any data rate. The transmitted information is correlated at the smallest data rate (i.e., the tier 1 rate) in the correlation filter (CF) of the wireless system by time multiplexing delayed versions of the PN code to the correlation filter core.

Abstract: An antenna assembly includes at least two active or main radiating omni-directional antenna elements arranged with at least one beam control or passive antenna element used as a reflector. The beam control antenna element(s) may have multiple reactance elements that can electrically terminate it to adjust the input or output beam pattern(s) produced by the combination of the active antenna elements and the beam control antenna element(s). More specifically, the beam control antenna element(s) may be coupled to different terminating reactances to change beam characteristics, such as the directivity and angular beamwidth. Processing may be employed to select which terminating reactance to use. Consequently, the radiator pattern of the antenna can be more easily directed towards a specific target receiver/transmitter, reduce signal-to-noise interference levels, and/or increase gain by using Radio Frequency (RF), Intermediate Frequency (IF), or baseband processing.

Abstract: A method of determining a trellis from a sequence of n symbols in a Viterbi detector. The method includes the steps of receiving a sequence of n symbols, defining partitioned sets according to a decision tree structure, and determining size of each set partitioning according to tap energy of the channel. The method also includes steps of determining a reduced set of connection paths between the current layer and a destination layer in the trellis by determining a value of a most likely oldest partitioned set in a current layer; and calculating branch metrics only for the current layers in the trellis in which the oldest partitioned set matches the determined value.

Abstract: A DC tracking arrangement comprises a first tracking unit for slow tracking receiving an input signal and generating a first output signal, a second tracking unit for fast tracking receiving the input signal and generating a second output signal, and a decision unit receiving the first and second output signal for selecting the first or second output signal.

Abstract: In an illustrative embodiment of the present invention, a reference signal including pilot information is transmitted from a base station to one or multiple field units over a pilot channel. A message is also sent to the field units over a paging channel to indicate an effective radiated power level at which the reference signal is transmitted on the pilot channel. Based on a received power level of the reference signal at a field unit and the effective radiated power level of the reference signal, a forward path loss is estimated at the field unit for the forward link between the base station and field unit. Assuming the path loss in the reverse link is approximately the same as the estimated forward link path loss, the field unit can transmit, a reply message in the reverse link so that the base station generally receives a message at-a desired power level.