Motorola Corporation

Michael H Retzer

David S Robins

Robert V Janc

Randy L Ekl

Steven C Jasper

Joseph E Phillips

Alan D Muehlfeld

Timothy W Markison

Andrew S Lundholm

Mario F Derango

Manohar A Joglekar

Denis Beaudoin

Ted A Kozlowski

Barry Moss

Scott P Howard

Nuruddin Ladhani

Earle G Long

A method and apparatus for improving throughput in a wireless local area (WLAN), which includes buffering a set of messages, identifying a target address for the set of messages, and concatenating the set of messages based on the target address. The target address can be either unicast, broadcast, multicast or combination of unicast, broadcast and multicast as described herein.

Method and apparatus for improving throughput in a wireless local area network

In one embodiment of the present invention, an access point () receives a multicast packet intended for a particular multicast group. Upon receipt, the access point only rebroadcast the multicast packet over a wireless segment if it determines that there is at least one wireless subscriber unit () belonging to the particular multicast group and associated with the access point that did not originate the multicast packet. Optionally, if the multicast packet signals an automatic rebroadcast of the multicast packet over the wireless segment, the access point automatically rebroadcasts the multicast packet without determining whether there is at least one wireless subscriber unit belonging to the particular multicast group and associated with the access point that did not originate the multicast packet.

Method for preserving wireless resources in a wireless local area network

A one-to-many dispatch method for use in a TDMA or other wireless telephone system. The one-to-many dispatch call is placed by sending a Request message from a Personal Station PS to a Control Center Station (CS) which assigns a channel with an Assignment message . The PS sends a call setup message over the control channel resulting in a channel assign message being broadcast repeatedly. Call connect messages over the Assigned Channel AC are also repeated from the CS to indicate the open connection. A hang timer is started when the PS ceases transmission of voice and the connection is torn down upon expiry of the hang timer unless another PS transmits a call setup message on the Assigned Channel AC before the expiry of the hang timer.

Radio telephone system with one-to-many dispatch system

A unique method and apparatus automatically switches between a voice mode and a data mode in a wireless communication device. In particular, a communication device (200) adapted to voice and data signals monitors a data network for data traffic for a first predetermined period of time (506), then monitors a cellular control channel (516) for cellular traffic during a sleep mode of the data network before establishing normal cellular operation. The method and apparatus increases efficient use of channel capacity by selectively switching between systems during periods of nonuse. Finally, according to other novel aspects of the present invention, user prompts (606, 618) enable efficient use of a communication device capable of transmitting and receiving both voice and data.

Method of and apparatus for operating a cellular phone in one of two

An apparatus and method adaptable to desired offsets for determining an undesired offset of a signal having a maximum and a minimum state that includes: providing a peak and trough estimate of, respectively, the maximum and minimum amplitude state; averaging such estimates to provide a reference level that is proportional to the undesired offset; and controlling the peak and trough estimates whenever a comparison of the signal and the reference level is, respectively, indicative of the maximum and minimum amplitude states to thus assure adaptation to the desired offset of the signal.

Apparatus and method for pattern adaptive offset restoration

A dual function interface operating in a Personal Computer Memory Card International Association (PCMCIA) mode of operation switches to an alternative interface operating in the appropriate mode of operation as defined by the alternative interface system specification. This is accomplished by setting a unique combination of address lines (203) and/or control lines (202) and automatically and transparently switching from the PCMCIA mode of operation to the alternate mode operation in response to the unique combination.

Dual function interface for PCMCIA compatible peripheral cards and

An apparatus and method for recovering packet data with unknown delays and error transients is disclosed that includes a received waveform containing a desired information signal relative to a fixed reference, for eliminating an undesired error in the received waveform where the error is localized in time relative to the received waveform to a transient interval, and recovering the desired information signal. Included also is a sampler, responsive to the received waveform, providing a series of time samples representative of the received waveform. A buffer, responsive to the time samples, for providing a plurality of representations of the received waveform at different instants of time, where the length of time is an appreciable duration of a transient interval. A reference slicker, responsive to the plurality of representations, for providing an estimate of a fixed reference. A signal recovery circuit, for comparing the plurality of representations with the estimate of the fixed reference, for purposes of recovering the desired information.

Apparatus and method for recovering packet data with unknown delays and

An apparatus is disclosed which is adaptable for indicating communication failures and eliminating an undesired pattern of physical values of a generated signal, the signal having physical values responsive to a sequence of information. The apparatus includes a protocol sequencer, responsive to the sequence of information and to the communication failure indications, and providing RESET and RETRY control signals; a framing flag generator, responsive to the RESET signal and providing a variable length framing flag, the length of the framing flag being dependent on the RETRY signal; a multiplex switch, responsive to the RETRY and RESET signals for generating a concatenation of the framing flag and sequence of information; a whitener generator, responsive to the RESET signal, for providing a known sequence of values; and a multiplier, for multiplying said concatenation of said framing flag and the sequence of information with the known sequence of whitener values.

Apparatus and method for data pattern sensitivity correction

An apparatus and method for recovering data in the presence of error transients is disclosed that includes a received waveform containing an information signal encoded at periodic time instants of a known period for eliminating an undesired amplitude error in the received waveform, where the error is slowly varying with respect to the known periods and recovering the desired periodic time instants. A delay element for delaying the received waveform by an amount equal to the period is included and a subtracting element for comparing the received waveform with the delayed waveform, and providing a timing recovery signal with zero crossing substantially less corrupted by the undesired amplitude error, and an averaging circuitry operating on the timing recovery signal for purposes of recovering the desired periodic time instants aids in recovering data in the presence of error transients.

Apparatus and method for recovering data in the presence of error

An apparatus is provided for generating a multiple-level amplitude modulated data signal. The circuit provides accurate data signal level control while minimizing transient errors. A controlling level, relative to an analog reference level is provided. Multiple bit reference levels are generated from the controlling level and analog reference level. A method is provided for selecting one of the reference levels.

Apparatus and method for generating a data signal

A wireless communications receiver having an adaptive squelch system and operable in multiple states including a receiver (11) that provides a received signal when operating in a clear (unscrambled) state and when operating in a secure (scrambled) state; a squelch function (13) that generates an unsquelch signal when the received signal satisfies a quality level; and a controller (15) that sets the quality level to a predetermined level that corresponds to the receiver operating state.

Communications receiver with an adaptive squelch system

A resilient housing actuated multi-level housing switch comprises a compression sensitive circuit which is actuated by compressing a resilient housing. The compression sensitive circuit comprises a compression sensing device which produces an analog signal, an A to D converter, and a microprocessor. The microprocessor is programmed with algorithms to control the power levels of communication equipment and volume levels based on signals produced by compressing the compression sensing device.

Resilient housing actuated multi-level switch

Disclosed is a signalling system wherein a private call initiating trunked subscriber enters a private ID number on an entry means. The trunked subscriber unit decodes the entered number and forms the ID code required to request a channel. The central controller receives the request and encodes an appropriate channel grant for a trunked private call. In another aspect of the present invention, the called subscriber unit may decode and display the ID of the calling subscriber.

Signalling system for trunked private calls

An apparatus and method for determining the period and frequency of a signal intefering with a desired Loran C signal are provided. A sample of the interfering signal is generated at a time corresponding to the peak of the autocorrelation function of the interfering signal with respect to the predetermined pulse tracking reference point of the Loran C signal. Indicia of the period and frequency of the interferer is obtained from the timing of the sample generated at the autocorrelation function peak.

Apparatus and method for determining the presence and frequency of a

A method and apparatus for attenuating an interfering signal corrupting a desired Loran C signal is provided. An interfering signal sample is determined which occurs at the peak of the autocorrelation function of the interfering signal such that the period of the interferer is known. The sample occurring at the peak of the autocorrelation function is added to or subtracted from the desired Loran C signal sample taken at a predetermined reference point during the pulses thereof such that the interfering signal is cancelled or substantially attenuated.

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Palatine, IL, United States of America

Michael H Retzer