Abstract: A communication protocol for use in a mobile cellular communication system using time division duplex establishes a communication channel between a user station (e.g., a handset) and a base station in a time slot by assigning a first time segment within the time slot for a user station transmission and assigning a second time segment within the time slot for a base station transmission. The protocol also provides for virtual time slots wherein a time segment assigned for periodic transmission from the base station to a given user station may be non-contiguous with respect to the time segment assigned for periodic transmissions from the user station to the base station.

Abstract: A technique for cyclic time hopping in a multiple access communication system, wherein each time frame of a TDMA system is divided into multiple time slots. A plurality of user stations, one for each time slot, communicate with a base station. Each user station regularly varies its relative time slot position in a pseudo-random pattern. Orthogonal time hopping patterns are determined from a root pattern according to a predetermined equation or relationship. The effect of transmitting bursts in a pseudo-random pattern is to break up the otherwise strict periodicity of TDMA bursts, and to produce a more noiselike spectrum for switching transients, thereby reducing the level of interfering spectral components from a TDMA transmission source. In some embodiments, the time hopping pattern may be restricted to only odd or even time slots. In such embodiments, a dead time slot may be declared periodically so as to increase the apparent randomness of the user station transmission patterns.

Abstract: A communication protocol for use in a mobile cellular communication system using time division duplex establishes a communication channel between a user station (e.g., a handset) and a base station in a time slot by assigning a first time segment within the time slot for a user station transmission and assigning a second time segment within the time slot for a base station transmission. The protocol also provides for virtual time slots wherein a time segment assigned for periodic transmission from the base station to a given user station may be non-contiguous with respect to the time segment assigned for periodic transmissions from the user station to the base station.

Abstract: A technique for modulating and demodulating CPM spread spectrum signals and variations of CPM spread spectrum signals. A spread spectrum transmitter includes a chip sequence generator for generating a chip sequence from a data stream, a switch for dividing said chip sequence into an odd chip sequence and an even chip sequence, and a modulator for generating and transmitting a continuous phase modulated signal from said odd chip sequence and said even chip sequence. A spread spectrum receiver comprises a plurality of non-coherent serial CPM correlators, each generating a correlation signal. In a preferred embodiment, the chip sequence generator of the transmitter comprises a table of symbol codes, each symbol code comprising a series of chips corresponding to a unique series of bits in said data stream, and each non-coherent serial CPM correlator is configured to detect one of the symbol codes.

Abstract: A simple and flexible over-air protocol for use with a mobile telephone system, having hand-held telephones in a microcell or other type of cellular communication system. A method in which user stations communicate with one or more base stations to place and receive telephone calls, in which the user stations are provided a secure voice or data link and have the ability to handoff calls between base stations while such calls are in progress. Each base station has a set of "air channels" to which it transmits in sequence. The air channels supported by each base station are called that base station's "polling loop". A user station receives general polling information on an unoccupied air channel, transmits responsive information to the base station, and awaits acknowledgment from the base station. Each base station may therefore simultaneously maintain communication with as many user stations as there are air channels in its polling loop.

Abstract: A simple and flexible over-air protocol for use with a mobile telephone system, having hand-held telephones in a microcell or other type of cellular communication system. A method in which user stations communicate with one or more base stations to place and receive telephone calls, in which the user stations are provided a secure voice or data link and have the ability to handoff calls between base stations while such calls are in progress. Each base station has a set of "air channels" to which it transmits in sequence. The air channels supported by each base station are called that base station's "polling loop". A user station receives general polling information on an unoccupied air channel, transmits responsive information to the base station, and awaits acknowledgment from the base station. Each base station may therefore simultaneously maintain communication with as many user stations as there are air channels in its polling loop.

Abstract: A correlation peak detector including an envelope detector, a peak-holder, a peak scaler, and a comparator detects the envelope of a correlator output signal, derives a peak threshold signal from the peak signal level produced by the correlator output signal, and compares the envelope of the correlator output signal to the peak threshold signal to produce a correlation peak detector output signal which indicates detection of a correlation peak. A minimum threshold signal is generated and provided to the comparator to inhibit detection of false peaks or noise. The comparator produces a correlation peak detector output signal which indicates occurrence of a correlation peak by producing a pulse whenever the magnitude of the envelope of the correlator output signal exceeds the sum of the magnitude of the peak threshold signal and the magnitude of the minimum threshold signal. Pulses in the correlation peak detector output signal may be used to synchronize receiver timing signals with a received signal.