Wi-lan Inc.

Motorola Corporation

Ensemble Communications, Inc.

Eli Arviv

Sheldon I Gilbert

Frederick Wales Price

David Gazelle

Kenneth L Stanwood

Israel Jay Klein

Rami Hadar

Steve Pollmann

Yair Bourlas

Stephen C Pollmann

Timothy Leo Gallagher

John Wiss

Blaine Clifford Readler

Pranesh Sinha

Sharon Akler

Brian Spinar

Ofer Zimmerman

Mark Shahaf

Rafael Carmon

Penny Efraim

Frederick W Price

Jacques Behar

Eliezer Fogel

Timothy L Gallagher

A method of simplifying the encoding of a predetermined number of bits of data into frames including adding error coding bits so that a ratio of the frame length times the baud rate of the frame times he bit packing ratio of the data divided the total bits of data is always an integer. The method may also convolutionally encode the bits of data so that the same equation is also always an integer.

Frame structure for an adaptive modulation wireless communication system

A method of simplifying the encoding of a predetermined number of bits of data into frames including adding error coding bits so that a ratio of the frame length times the baud rate of the frame times the bit packing ratio of the data divided the total bits of data is always an integer. The method may also convolutionally encode the bits of data so that the same equation is also always an integer.

The invention relates to communication systems and to systems and methods for implementing adaptive call admission control (CAC) in such systems. Adaptive call admission control can determine what CPE to base station calls (connections) are allowed at any given time. CAC, coupled with precedence, can further determine what connections are suspended if less bandwidth is available than is currently committed. Multiple techniques are disclosed to select connections for suspension. These techniques include suspending enough connections through the affected CPE until there is enough bandwidth to meet the remaining commitment, randomly (or in a round robin fashion) choosing connection to suspend from the entire set of connection, and using precedence priority levels.

Adaptive call admission control for use in a wireless communication system

Apparatus, system and method for synchronizing one or more clocks across a communication link. A slave clock may be synchronized to a master clock by means of a synchronization signal sent from the master to the slave clock side of the link. The synchronization signal may be an expected signal pattern sent at intervals expected by the slave side. The slave clock may correlate received signals with a representation of the expected synchronization signal to produce a correlation sample sequence at a first sample rate which is related as n times the slave clock rate. The synchronization signal receipt time indicated by the correlation sample sequence may be refined by interpolating the correlation sample sequence around a best correlation sample to locate a best interpolation at an interpolation resolution smaller than the sample resolution. The best interpolation may in turn be further refined by estimating between interpolator outputs adjacent to the best interpolation output. The synchronization signal receipt time thus determined is compared to the expected time based upon the slave clock, which is adjusted until the times match. After initialization, all slave clock errors are preferably accumulated to prevent long-term slip between the slave and master clocks. Formerly independent master and slave clocks synchronized across the communication link constitute a noncommon clock which may be compared on each side of the link to secondary independent clocks, and the secondary independent clocks may then be separately synchronized by adjusting one to have the same difference from its local noncommon clock as the secondary clock on the other side of the link has from its local noncommon clock.

Synchronizing clocks across a communication link

A slave clock may be synchronized to a master clock by means of a synchronization signal sent from the master to the slave clock side of the link. The synchronization signal may be an expected signal pattern sent at intervals expected by the slave side. The slave clock may correlate received signals with a representation of the expected synchronization signal to produce a correlation sample sequence at a first sample rate which is related as n times the slave clock rate. A best interpolation may in turn be further refined by estimating between interpolator outputs adjacent to the best interpolation output. The synchronization signal receipt time thus determined is compared to the expected time based upon the slave clock, which is adjusted until the times match. The best interpolation may in turn be further refined by estimating between interpolator outputs adjacent to the best interpolation output.

One or more clocks are synchronized across a communication link using a synchronization signal sent from a master to a slave clock. The synchronization signal may be an expected signal pattern sent at intervals expected by the slave. The slave clock may correlate received signals with a representation of the expected synchronization signal to produce a correlation sample sequence at a first sample rate. The synchronization signal receipt time is compared to the expected time and the slave clock is adjusted until the times match. Master and slave clocks synchronized across the communication link constitute a noncommon clock which may be compared on each side of the link to secondary independent clocks. The secondary independent clocks may be separately synchronized by adjusting one to have the same difference from its local noncommon clock as the secondary clock on the other side of the link has from its local noncommon clock.

The present invention is a method of simplifying the encoding of a predetermined number of bits of data into frames. The method adds error coding bits so that a ratio of the frame length times the baud rate of the frame times the bit packing ratio of the data divided the total bits of data is always an integer. The method may also convolutionally encode the bits of data so that the same equation is also always an integer.

A method of assigning downlink time slots to receive units where the units may generate data using different modulation schemes. The method preferably assigns the downlink time slots as a function of the complexity of modulation schemes employed by the units. Further, the method preferably assigns the time slots from the least complex modulation scheme to the most complex scheme. The method may further assign uplink time slots to transmit units where the transmit units may generate data using different modulation schemes. The method preferably assigns the uplink time slots as a function of the complexity of modulation schemes employed by the uplink units. Further, the method preferably assigns the uplink time slots from the least complex modulation scheme to the most complex scheme. In other embodiments, the downlink time slots are assigned as a function of the bit per symbol rate employed by the receive units, preferably from the lowest bit per symbol rate to the highest bit per symbol rate. Further, the uplink time slots are assigned as a function of the bit per symbol rate employed by the transmit units, preferably from the lowest bit per symbol rate to the highest bit per symbol rate. The present invention is also a method of simplifying the encoding of a predetermined number of bits of data into frames. The method adds error coding bits so that a ratio of the frame length times the baud rate of the frame times the bit packing ratio of the data divided the total bits of data is always an integer. The method may also convolutionally encode the bits of data so that the same equation is also always an integer. The present invention is also a method of updating the weights of a FIR filter where the filter processes symbols having variable modulation rates. When the modulation rate of the incoming symbols changes, the weights corresponding to the first symbol having the new modulation rate are changed based as the symbol propagates through the filter.

A method to train a radio includes the steps of: in a radio ( ), receiving a slot of information ( ) containing at least an initial portion ( ) containing training information ( ), a second portion ( ) containing training information ( ), which second portion ( ) is separated from the initial portion ( ), and a concluding portion ( ) containing training information ( ), which concluding portion ( ) is separated from the second portion ( ). The method combining one of the initial portion ( ) with the concluding portion ( ) of a previous slot of information ( ) and the concluding portion ( ) with an initial portion ( ) of a subsequent slot of information ( ) to provide an at least one combined portion of training information. The method using the at least one combined portion of training information and the second portion of training information to train the radio.

Method to train a radio receiver

A system and method for enhancing the performance of an equalizer in a modem. Multiple techniques are disclosed which improve the modem performance. A first technique uses stored parameters for each burst from each remote site to demodulate a received data stream. A second technique compensates for the gain droop caused by storing parameters across each burst. A third technique minimizes errors caused by adapting the equalizer coefficients for each data burst by analyzing the SN ratio and error rate of the received burst. A fourth technique improves the convergence of the equalizer by using a two-part preamble, whereby both parts are transmitted using different modulation techniques. A fifth technique is provided which performs a soft reset of the modem without performing a complete reset of the modem. A sixth technique determines a modem adaptation factor based on the expected modulation type of an incoming burst transmission. A seventh technique calculates a phase correction value for the stored tap values and applies the value to the incoming signal.

Equalizer performance enhancements for broadband wireless applications

On embodiment of the system and method provides asymmetric adaptive modulation which allows uplink and downlink subframes of data to be transmitted between a base station and a CPE with different modulation schemes, thus increasing the efficiency of downlink transmissions while maintaining the stability of uplink transmissions. In systems with multiple CPEs, each CPE and base station pair can independently select their uplink and downlink modulation techniques. The system and method are also adaptive in that they adjust the modulation schemes based on, for example, signal to noise ratio measurements or bit error rate measurements.

Asymmetric adaptive modulation in a wireless communication system

A communication method is provided in which mobiles operating in a trunk mode operation transmit a message on a direct mode operation channel indicating a trunk mode operation connection is present. If a mobile outside the range of coverage of the trunking system receives the message it will deduce from the message the slot structure of the trunk mode channel and its timing, and will then be able to transmit a request for a direct mode connection on an appropriate slot of the trunk mode channel. Some or all of the mobiles operating in trunk mode will then be able to switch to direct mode to connect with the mobile outside the range of coverage.

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Modiin, Israel

Eli Arviv