Abstract: A technique for correlating a sequence of signal sample values with a predetermined digital code to produce correlation values for shifts in the sequence of signal sample values relative to the predetermined digital code is disclosed. The technique is realized by combining subgroups of the signal sample values in the sequence to form sets of precombinations, and then selecting one precombination from each set of precombinations to provide a plurality of selected precombinations. The plurality of selected precombinations are then added or subtracted to produce a correlation value corresponding to a shift in the sequence of signal sample values.

Abstract: The present invention discloses a CDMA coding method including the steps of converting the information to be transmitted into digital form, error-correction coding the digital information, and assembling the coded symbols into frames having N symbols. Each coded information symbol within a frame is then repeated a first number of times L1 in succession and the sign of select repeated symbols, determined by a spreading code generator, is changed to produce a symbol block of N×L1 symbols. The symbol block is then repeated a second umber of times L2, where for each block repeat, a block sign change is applied to all symbols of the same block; the sign for each block may also be supplied by the spreading code generator. The resulting L2×N×L1 coded and repeated symbols are then modulated upon a radio frequency carrier and transmitted to a receiver simultaneously with similar symbols intended for other receivers, where different information is transmitted to a plurality of receivers.

Abstract: A power amplifier uses a modulation technique that varies amplitude of a drive signal and, optionally, phase angle of the drive signal. The power amplifier comprises two coupled amplifiers, a first one of which is operated saturated to produce a constant voltage output. The first amplifier is coupled to a second one of the amplifiers via a quarter wave transmission line. The second amplifier is operated in a linear mode to deliver an output signal controlled by an amplitude-modulating signal. The amplitude-modulating signal may be a bipolar modulation signal that produces both positive and negative outputs from the second amplifier that add to or subtract from the output from the first amplifier to develop at a load impedance net output signal amplitudes varying between a minimum or “trough” amplitude and a maximum or “crest” amplitude.

Abstract: A radio base station having a plurality of directional sector antennas for providing communications with outstations lying at different azimuth angles to the base station is disclosed in which the antennas transmit signals using one or both of two orthogonal polarizations such as left hand or right hand circular antennas and polarization and which also measures interference levels on different frequency channels that are used for allocating an optimum channel and polarization for connecting a call. Each of the outstations comprise at least one antenna of selectable polarization.

Abstract: A decoder also includes a channel estimator to estimate coefficients describing a channel through which the signal has propagated, a signal predictor that combines the channel estimates with corresponding samples of the signal to obtain a metric, and a metric accumulator to accumulate the metrics for hypothesized symbol sequences to determine the likelihood indications. The hypothesized symbol sequences include partial symbols that select a subgroup of the symbol alphabet. This allows those parts of a symbol that are most important for predicting signal samples to be retained in a hypothesized state while the remaining parts can pass to a path history memory, thereby reducing the number of possible states that must be considered.

Abstract: A method and apparatus for predicting signal values for signals that have not yet been received wherein the information stream transmitted has been divided into a first stream and a second stream. A first Q component is predicted based on values stored in a state memory for the first bit stream. A first I component is predicted using the first predicted Q component and a previous bit from the state memory for the first bit stream. Then, a second Q component is predicted based on values in the state memory for the second bit stream. A second I component is then predicted using the second predicting Q component and the previous bit from the second bit stream. The first I component and the second Q component are added to obtain a combined I value and the first Q component and the second I component are added to obtain a combined Q value.

Abstract: A communication system and method for transmitting relatively short data messages in the communication system. A dedicated frequency is sequentially switched into each of a plurality of satellite beams or traffic channels to transmit data messages at an increased power level to provide an increased signal margin. The increased power level of the dedicated frequency can be combined with coding and bit and message repetition to further increase the signal margin.

Abstract: A processor architecture and associated method improve efficiency of memory accesses and thereby reduces power consumption. New addressing modes reduce most instructions to one or two bytes in length, including immediate addressing of 32-bit addresses. A full instruction set provides complete arithmetic and logical operations using index registers and accumulator while minimizing external memory access.

Abstract: Techniques for providing secure electronic communications, for example communications relating to asset trading, are described. Symmetrical usage of encryption keys by first and second parties engaged in these communications provide enhanced security. The establishment of trusted registries, e.g., databases, which include electronic asset representations, allow for trades to be enacted without significant human intervention.

Abstract: A mobile radio telephone having a simplified architecture including a reduced number of integrated circuits and a reduced number of RF connections. A dual band, dual mode mobile phone can be constructed using either a single crystal reference oscillator or two crystals such that alternative symbol rates, channel spacings, or transmit/receive duplex spacings can be achieved.

Abstract: Pseudorandom number sequence generation is a significant component in a variety of existing and proposed CDMA systems. In CDMA handsets, techniques for sequence generation in conjunction with sleep mode are an important component in paging performance and standby time. Techniques are described herein for properly advancing sequence states in conjunction with, for example, sleep mode without detrimentally draining battery capacity.

Abstract: Time slots of a plurality of time-division multiple access (TDMA) cellular radiotelephone base stations are synchronized. Cellular radiotelephone frequencies are allocated among the plurality of base stations according to a first frequency allocation system in a first synchronized time slot and according to a second frequency allocation system in a second synchronized time slot. Each frequency allocation system may include an adaptive channel allocation system, a frequency reuse system, a frequency reuse partitioning system or a fixed frequency reuse system. Spreading codes of a plurality of code-division multiple access (CDMA) cellular radiotelephone base stations are synchronized. Cellular radiotelephone frequencies are allocated among the plurality of base stations according to a first frequency allocation system for a first synchronized spreading code and according to a second frequency allocation system for a second synchronized spreading code.

Abstract: A method has the steps of generating a first control message having a plurality of message symbols and a first audio message to be transmitted from a first radio-communications device to a second radio-communications device. The first audio message is sampled to obtain a first plurality of audio samples, each with an instantaneous signal valve, and a first radio frequency signal which varies in frequency from a first predetermined radio frequency dependent on the instantaneous signal valves of the first plurality of samples is generated. The first radio frequency signal is formatted into a first pulsed radio frequency signal, each pulse having a time duration representative of one of the plurality of message symbols of the first control message, which is transmitted from the first radio-communication device to the second radio-communication device.

Abstract: A fractional synthesis approach and arrangement are presented which achieve fine frequency resolution with low phase noise while at the same time retaining a high phase comparison frequency/fast frequency changing speed. An output signal having a desired output frequency is generated by a voltage controlled oscillator (VCO). An output divider divides the output frequency by an output divisor N to produce an output pulse train. The output divisor N may be equal to an output integer N or the output integer plus one N+1, for example, and may change during the generation of a single output frequency. For different desired output frequencies, the value of the output integer N may be varied. A reference divider divides a reference frequency by a reference divisor M to produce a reference pulse train. The reference divisor M may be equal to a reference integer M or the reference integer plus one M+1, for example, and may change during the generation of a single output frequency.

Abstract: A multi-channel transmit amplifier array comprising a multiplicity N of coupled power amplifier elements is disclosed. The number of channels provided for amplifying desired signals for transmission is less than N, by at least one. In this case, the unused channel is used to inject an intermodulation compensation waveform specifically tailored to reduce intermodulation generated in all of the other N−1 signal paths. Instantaneous complex waveform values for the intermodulation compensation waveform may be systematically computed from the instantaneous complex values of the N−1 desired signals in such a way as to minimize the greatest signal amplitude in any of the N signal paths.

Abstract: A transmitter encodes a number 2N data bits by using N data bits to select one of 2N levels of a cosine wave and the other N data bits to select one of 2N levels of a sine wave. The modulation attains the cosine wave levels at instants offset by half an N-bit symbol interval with respect to the sine wave levels, and is called Offset QAM (OQAM). A received OQAM signal is amplified, filtered and digitized at a sampling rate of preferably only one sample per N-bit half-symbol interval. Successive N-bit half-symbols comprise information modulated alternately on a cosine and a sine carrier wave. The receiver may remove this successive rotation by applying successive derotations of successive digitized samples by like amounts. The derotated samples are then correlated with known sync half-symbols. The sync correlations determine a set of channel coefficients describing the dependence of each digitized sample on one or more unknown half-symbols.

Abstract: Time slots of a plurality of time-division multiple access (TDMA) cellular radiotelephone base stations are synchronized. Cellular radiotelephone frequencies are allocated among the plurality of base stations according to a first frequency allocation system in a first synchronized time slot and according to a second frequency allocation system in a second synchronized time slot. Each frequency allocation system may include an adaptive channel allocation system, a frequency reuse system, a frequency reuse partitioning system or a fixed frequency reuse system. Spreading codes of a plurality of code-division multiple access (CDMA) cellular radiotelephone base stations are synchronized. Cellular radiotelephone frequencies are allocated among the plurality of base stations according to a first frequency allocation system for a first synchronized spreading code and according to a second frequency allocation system for a second synchronized spreading code.

Abstract: A digital beamforming network for transmitting a first number of digital information signal using a second number of antenna array elements is disclosed. Assemblers are used for assembling one information bit selected from each of the information signals into a bit vector. Digital processors have an input for the bit vector and a number of outputs equal to the second number of antenna elements and process the bit vector. Finally, modulation waveform generators coupled to each of the second number of outputs generate a signal for transmission by each antenna element.

Abstract: A communication system and method with orthogonal block encoding is provided. Encoded signals are transmitted by repeating transmissions of symbol blocks with a phase or sign change selected for each block from a sequence of phase or sign changes. Different symbols are transmitted using orthogonal sequences. The decoding uses different orthogonal sequences for separating the received encoded signals into corresponding separate channels. The orthogonal encoding is removed from the encoded transmitted signals and corresponding ones of the repeated symbols are added in successively received repeated blocks after the orthogonal encoding is removed. A transmitter uses a digital source encoder to encode information into symbols, and each symbol is repeated a preselected number of times to successively produce groups of repeated bits. Each repeat bit is changed in phase or sing by application of a sign or phase change determined by a selected assigned orthogonal code associated with the transmitter.

Abstract: Modulation systems and methods can modulate a stream of complex numbers representing a desired modulation of a radio signal by representing a real part of each of the complex numbers in a stream of complex numbers representing a desired modulation of a radio signal, as a plurality of first digits of decreasing numerical significance and representing an imaginary part of each of the complex numbers as a plurality of second digits of decreasing numerical significance. A respective one of the first digits and a respective one of the second digits of like numerical significance are grouped to form a plurality of phase control symbols. A respective phase control symbol is then used to control the phase of an output signal at the radio carrier frequency from a respective one of the plurality of power amplifiers. Each of the power amplifiers provides an output power level that is related to the numerical significance of the first and second digits that form the associated phase control symbol.