Abstract: A finite impulse response (FIR) filter including a delay line and a plurality of arithmetic units. Each arithmetic unit is coupled to a different one of a plurality of tap points of the delay line, is configured to receive a respective signal value over the delay line, and is associated with a respective coefficient. Any given one of the arithmetic units is configured to receive a respective control word. The respective control word specifying: (i) a plurality of trivial multiplication operations, and (ii) a plurality of bit shift operations. Any given one of the arithmetic units is further configured to estimate or calculate a product of the respective signal of the arithmetic unit respective signal value and the respective coefficient of the arithmetic unit by performing the trivial multiplication operations and bit shift operations that are specified by the respective control word that is received at the given arithmetic unit.

Abstract: A finite impulse response (FIR) filter including a delay line and a plurality of arithmetic units. Each arithmetic unit is coupled to a different one of a plurality of tap points of the delay line, is configured to receive a respective signal value over the delay line, and is associated with a respective coefficient. Any given one of the arithmetic units is configured to receive a respective control word. The respective control word specifying: (i) a plurality of trivial multiplication operations, and (ii) a plurality of bit shift operations. Any given one of the arithmetic units is further configured to estimate or calculate a product of the respective signal of the arithmetic unit respective signal value and the respective coefficient of the arithmetic unit by performing the trivial multiplication operations and bit shift operations that are specified by the respective control word that is received at the given arithmetic unit.

Abstract: A single, common correlation filter (CF) core is provided in a receiver for recovery of data from received code division multiple access (CDMA) signals. Signals are received over CDMA channels with different data rates, where the received signals include user information such as pilot and data symbols that have been spread according to different despreading rates including tier 1, tier 2 and tier 3 rates, where tier 1 is the smallest despreading rate. The received signal is correlated at the smallest despreading rate in the correlation filter (CF) by time multiplexing delayed versions of the pseudorandom noise (PN) code. The correlated information is then demultiplexed and pilot-aided QPSK demodulated. The demodulated information is summed at the proper integer multiple of the tier 1 rate to achieve tier 2 and tier 3 despreading rates. According to an embodiment, the three strongest multipaths components in terms of the received power are selected in a window or time period for optimal information recovery.

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: 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 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: Individual RF cables span between element/transceiver pairs in traditional beam forming systems, and the number of elements in an array used for beam forming is thus restricted. To reduce the number of RF cables but maintain or increase the number of elements in an antenna array, an embodiment of the present invention includes electronics at the base of an antenna tower that apply digital multiplexing codes to signals communicated to electronics located at the top of the antenna tower. The electronics at the top demultiplex the signals and transmit them via the antenna array. Received RF signals are processed in a like manner in a reverse direction. Fewer transmission paths (e.g., RF or fiber optic cables) than the number of elements in the antenna array can be used. More antenna elements provide benefits, such as higher user capacity, more antenna beams, narrower antenna beams, and higher in-building penetration.

Abstract: An automatic gain control device and a related method for its operation, using a first-order control loop for adjusting a received communication signal to compensate for variations in received signal power. The device bases its adjustments on a measure of the average received root-mean-square (rms) signal power and, in its preferred form, adjusts a loop gain adaptively to react rapidly to large input signal variations. The loop gain is adjusted based on measurement of the average power of an error signal and on the sign of the error signal power. Optional features include an automatically adjustable power set point.

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: 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.

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 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: A reduced-complexity automatic frequency control (AFC) loop to match the frequency of a receiver to that of a transmitter. A received input signal is multiplied with the sine and cosine signals of a voltage-controlled-oscillator, digitized and filtered, and the sign (the most significant bit) of the cosine function of the received input signal is sliced off by a sign slicer circuit to provide an input to two sign gates. The outputs of the two sign gates are added to produce an estimate of the frequency error, which is used to control the voltage-controlled-oscillator to match the received signal's frequency. The required number of multiplier circuits required to implement the AFC loop is reduced from prior art AFC loops by the use of the sign slicer circuit and the use of the sign gates.

Abstract: A method and apparatus for creating non-interfering signals to be simultaneously transmitted over a common frequency in a wireless communication systems, such as a CDMA system, without the use of orthogonal codes and/or orthogonal code generation techniques. The system provides a pseudorandom combiner that receives the information signal and a pseudorandom code sequence and combines the information signal with the pseudorandom code sequence to produce the first combined signal. A channel sequence combiner receives the first combined signal and a repetitive maximum length channel sequence and combines these signals to produce a second combined signal. A selector receives the first combined signal, the second combined signal and a repetitive strobe signal, and selects either the first combined signal or the second combined signal to produce a modulated signal based upon a value of the repetitive strobe signal.