Omnipoint Corporation

Intel Corporation

Claude M Williams

Ryan N Jensen

Logan Scott

Charles L Lindsay

Randolph L Durrant

Mark T Burbach

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.

Communication protocol for spread sprectrum wireless communication system

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. In a preferred embodiment, spread spectrum communication is employed for base station and user station transmissions.

Cyclic time hopping in time division multiple access communication system

Communication protocol for spread spectrum wireless communication system

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. The spread spectrum receiver selects a data symbol based on said correlation signals output from the non-coherent serial CPM correlators. A spread spectrum preamble may be used to set initial timing for the non-coherent serial CPM correlators.

Non-coherent spread-spectrum continuous-phase modulation communication

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. The ability of a user station to communicate on any unoccupied air channel makes the protocol air-channel agile, while the stability of user station and base station clocks may define air channels, gaps, and minor frames.

Communication protocol for spread spectrum communication

Method for power control in a TDMA spread spectrum communication system

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. Simultaneous detection of peaks in a plurality of correlator output signals is accomplished by individually comparing each correlator output signal's envelope with the peak threshold signal to produce a plurality of correlation peak detector output signals, and combining the correlation peak detector output signals to produce a combined correlation peak detector output signal having a pulse whenever a correlation peak is detected in any of the plurality of correlator output signals.

Growing community of inventors

Colorado Springs, CO, United States of America

Claude M Williams