Teknekron Communications Systems, Inc.

At&t Bell Laboratories

Tcsi Corporation

Adicom Wireless, Inc.

Carlson Wireless, Inc.

Telephone and Telegraph Company, At&t Bell Labs

Christopher Flores

Saman Behtash

Keith Jarett

Chun-Meng Su

David G Messerschmitt

Bhaskarpillai Gopinath

Huihung Lu

Adel Ghanem

Subrahmanyam Dravida

Pravin Kumar Johri

Bharat Tarachand Doshi

John Ormond Limb

Ronald Ross

Karl Yick

Hulhung Lu

Oswald Correya

Edward Chien

An acquisition module for acquiring signal timing in a CDMA system has a register for storing and organizing synchronization code, at least 4 match filters for match filtering between I/Q samples and the corresponding synchronization code, at least 4 absolute value blocks for determining absolute values of match filtering results, a summation function for summing results obtained through match filtering and through absolute value taking, and a control logic for controlling the acquisition process, characterized in that the acquisition module loads a 64-bit section of synchronization code and I/Q complex samples and match filters them in a simultaneous manner and, upon registering a value greater than a preset threshold, acquires an initial timing, the initial timing being verified over the remaining 64-bit sections of synchronization code using the same control circuitry used in acquiring the timing.

Fast acquisition module for a code division multiple access (CDMA) wireless local loop (WLL) system

A multi-rate wireless communications system that supports a plurality of distributed user terminals in full-duplex simultaneous communications with a central base station, where each user terminal is provided on demand with one of multiple bit rates at a negotiated QOS is provided. Each user is assigned a variable bit rate, a variable processing gain, a variable transmit power and a unique fixed rate spreading code, resulting in a constant bandwidth signal received at a relative power level corresponding to the negotiated QOS. This application can be applied to systems including wireless local loop and mobile cellular. By adjusting signal energy and interference energy, variable bit rates and negotiated QOS parameters can be supported. The forward link between base-station and user terminal, and the reverse link between the user terminal and base-station, can correspond to either a Frequency Division Duplexing (FDD) arrangement where the forward and reverse links occupy different carrier frequencies but overlap in time, or a Time Division Duplexing (TDD) arrangement where the forward and reverse links occupy the same carrier frequency but are in non-overlapping time intervals.

Multi-rate wireless communications system

A protocol for wireless local area network communication between a base stationary unit and a plurality of wireless terminals is disclosed. The main features of this protocol is based upon channel reservation requests by active wireless terminals. Contention is resolved and authorization is granted with data message signals transmitted by the authorized wireless terminal either immediately for asynchronous service or periodically for a time-based service. The system further provides for the base stationary unit to query the receipt of the data message signal by the wireless terminal authorized to receive the transmission. If no response signal is received, then the base stationary unit would authorize for itself transmission of the data message to relay it, either 'over the air' or via wired connection to another base stationary unit in another data cell. The synchronous nature of the method provides for power saving by allowing the receiver and/or transmitter to be powered down during idle and other time slots.

Method and apparatus for a wireless local area network

In the present invention a wireless communication system is disclosed. A base unit communicates with a remote unit. The system comprises means for transmitting, using CDMA, between the base unit and the remote unit, in one of a plurality of frequencies channels selected. In one period of time, the base unit transmits and in another period of time, different from the one period, the remote unit transmits. Further, the system comprises means for changing the one frequency channel selected to another frequency channel, different from the one frequency channel, in response to interference in the one frequency channel. Thus, communication between the base unit and the remote unit is then affected over the another frequency channel.

Wireless communication system

In a wireless communication system between a base unit and a remote unit, the base unit transmits periodically a sync signal in a first selected time period in a selected frequency channel. The remote unit scans the frequency channels to detect the sync signal. The remote unit transmits a response signal in the selected frequency channel. The response signal is transmitted in a second selected time period different from the first selected time period. In addition, the remote unit transmits a first control signal encoded by a first code in the selected frequency channel in a third selected time period, different from the first and second selected time periods, containing a set of functional capabilities of the remote unit. The base unit receives and decodes the first control signal to derive the set of functional capabilities of the remote unit and compares it to its own set of functional capabilities to determine a common set of functional capabilities. The base unit transmits a second control signal encoded by the first code in the same selected frequency channel in a fourth selected time period containing the common set of functional capabilities. Thereafter, communication between the base unit and the remote unit is based upon a functional capability selected from the common set.

Method and an apparatus for establishing the functional capabilities for

A facility is provided for use in a packet switch to control unnecessary multiple retransmissions of a data packet. In an exemplary embodiment of the invention, such control is achieved by tracking in a list the sequence numbers of transmitted data packets and retransmitting a data packet only if its sequence number appears in the list prior to the sequence number of the last data packet that is received correctly by a receiver. The sequence number associated with a retransmitted data packet is deleted from the list and then appended to the list to place the number in proper relationship with the sequence numbers of data packets transmitted after the initial transmission of the retransmitted data packet.

Data services retransmission procedure

In the present invention a method of re-establishing a wireless communication after a communication break is disclosed. Prior to the communication break, a base unit transmits to a remote unit a table of channels of communication to be used. The base unit also transmits a clock signal value to the remote unit. After a communication break, the remote unit continues to count the clock signals generated from a clock signal source internal thereto. The remote unit applies a function to the value of the clock signal to obtain an entry in the table. The channel of communication associated with the entry in the table is selected by the remote unit. The base unit continues to count the clock signals generated internal thereto. The base unit applies the same function as the function used by the remote unit to the value of the clock signal to obtain an entry in the table. The base unit selects the channel of communication associated with the entry in the table. Thereafter, communication is re-established over the channel of communication associated with the entry in the table.

Method and an apparatus for re-establishing wireless communication

A digital transmission system includes a plurality of stations sharing a common transmission line. Variable length messages, set off by flags, are exchanged between pairs of stations. While a message is being received, the downstream portion of the transmission line is segmented to permit simultaneous use by another station pair. If a message is received from an upstream station while a message is being transmitted downstream, an abort message flag terminates the transmitted message abruptly to permit flowthrough of the received message. When any station is not in use or out of order, it is bypassed to permit use of the transmission line by the rest of the stations.

Shared data transmission system

In order to control the transfer of packets of information among a plurality of stations, e.g., digital computers, the instant communications system, station and protocol contemplate first and second oppositely directed signal paths. At least two stations are coupled to both the first and the second signal paths. A station includes arrangements for reading one signal from the first path and for writing another signal on the first path. The one signal is read from the first path by an arrangement which electrically precedes the arrangement for writing the other signal on the first path. A similar read arrangement is electrically preceding a write arrangement on the second path. If the station has a packet to transmit, it can overwrite a busy control field of the one signal packet on either path. Having read the one signal on the path, a logical interpretation may be made within the station as to whether the path is busy or is not busy. If the path is not busy, the packet may be written on the path by overwriting any signal thereon. If the path is busy, the station may defer the writing until the path is detected as not busy through a busy control field. The packets flow down the path to a destination station. Eventually all packets will be transmitted and the busy control field may be detected at an end station for indicating the event that all packets have been transmitted. The end station on one path acts as the head station on the other oppositely directed path. Hence, responsive to detecting that all packets have been transmitted, the head station on the other path may transmit an end cycle packet, responsive to which event a new cycle may be started by initializing each station on the one path and by permitting each initialized station to transmit.

Growing community of inventors

Oakland, CA, United States of America

Christopher Flores