Abstract: A method and apparatus are provided that determine a frequency dependent calibration vector for a set of transmit or receive chains of a radio communications system using only differential phase and amplitude between the transmit chains and the receive chains, respectively. In one embodiment, the invention includes an antenna array adapted to transmit and receive radio communications signals with a plurality of other terminals, a transmit chain to transmit a calibration signal through the antenna array to a transponder on at least two different frequency bands, and a receive chain to receive through the antenna array a transponder signal from the transponder, the transponder signal being received on at least two different frequency bands and being based on the calibration signal.

Abstract: A method and apparatus are provided that determine a frequency dependent calibration vector for a set of transmit or receive chains of a radio communications system using only differential phase and amplitude between the transmit chains and the receive chains, respectively. In one embodiment, the invention includes an antenna array adapted to transmit and receive radio communications signals with a plurality of other terminals, a transmit chain to transmit a calibration signal through the antenna array to a transponder on at least two different frequency bands, and a receive chain to receive through the antenna array a transponder signal from the transponder, the transponder signal being received on at least two different frequency bands and being based on the calibration signal.

Abstract: In one embodiment, the present invention comprises transmitting a broadcast burst in a broadcast channel from a base station of a radio communications system. The invention further comprises receiving a request burst from a user terminal, and transmitting a message burst from the base station to the user terminal from which the request was received. The message burst includes a description of the channels available on the radio communications system for receiving messages from user terminals.

Abstract: A system and related methods for clustering multi-point communication targets is presented. According to one aspect of the invention, a method comprising measuring one or more performance characteristics associated for each of at least a subset of a plurality of targets in a wireless communication system, and selectively building one or more clusters, each cluster including one or more target(s) and sharing a wireless communication channel, based at least in part on the performance characteristics.

Abstract: A method and apparatus are provided that determine group delay for a set of transmit or receive chains over a wide frequency band without causing significant interference with simultaneous users of the system. In one embodiment, the invention includes an antenna array adapted to transmit and receive radio communications signals with a plurality of other terminals, the communications signals each using a particular minimum bandwidth, a transmit chain to transmit a calibration signal through the antenna array to a transponder on at least two different frequency bands within the minimum bandwidth, and a receive chain to receive through the antenna array a transponder signal from the transponder, the transponder signal being received on at least two different frequency bands and being based on the calibration signal. A signal processor determines a frequency dependent calibration vector based on the at least two frequency bands of the transponder signal as received through the receive chain.

Abstract: A method and apparatus for estimating the downlink signature for a remote transceiver which is part of a wireless communication system that includes a main transceiver for communicating with the remote transceiver. The main transceiver includes an array of transmit antenna elements. The method uses the remote transceiver for receiving signals when the main transceiver transmits downlink calibration signals. When the main transceiver also has a receive antenna array, the remote transceiver can transmit uplink calibration signals to the main transceiver for determining an uplink signature. The downlink and uplink signatures are used to determine a calibration function to account for differences in the apparatus chains that include the antenna elements of the arrays, and that enable downlink smart antenna processing weights to be determined from uplink smart antenna processing weights when the main transceiver includes means for smart antenna processing according to weights.

Abstract: A method and apparatus for estimating the downlink signature for a remote transceiver which is part of a wireless communication system that includes a main transceiver for communicating with the remote transceiver. The main transceiver includes an array of transmit antenna elements. The method uses the remote transceiver for receiving signals when the main transceiver transmits downlink calibration signals. When the main transceiver also has a receive antenna array, the remote transceiver can transmit uplink calibration signals to the main transceiver for determining an uplink signature. The downlink and uplink signatures are used to determine a calibration function to account for differences in the apparatus chains that include the antenna elements of the arrays, and that enable downlink smart antenna processing weights to be determined from uplink smart antenna processing weights when the main transceiver includes means for smart antenna processing according to weights.

Abstract: A method and apparatus for estimating the downlink signature for a remote transceiver which is part of a wireless communication system that includes a main transceiver for communicating with the remote transceiver. The main transceiver includes an array of transmit antenna elements. The method uses the remote transceiver for receiving signals when the main transceiver transmits downlink calibration signals. When the main transceiver also has a receive antenna array, the remote transceiver can transmit uplink calibration signals to the main transceiver for determining an uplink signature. The downlink and uplink signatures are used to determine a calibration function to account for differences in the apparatus chains that include the antenna elements of the arrays, and that enable downlink smart antenna processing weights to be determined from uplink smart antenna processing weights when the main transceiver includes means for smart antenna processing according to weights.

Abstract: A method and apparatus are provided that performs spatial processing, timing estimation and frequency offset using a training sequence of a received burst. According to one aspect of the present invention, the invention includes receiving a burst having a known training sequence at a set of diversity antennas, sampling the received burst at each antenna, determining a coarse timing estimate for samples from at least one antenna, and determining a spatial weighting vector using the coarse timing estimate. The embodiment further includes applying the spatial weighting vector to the received burst samples for each antenna to form a single channel signal, determining a fine timing estimate for the single channel signal, determining a second spatial weighting vector using the fine timing estimate, applying the second spatial weighting vector to the received burst samples for each antenna to form a second single channel signal, and demodulating the second single channel signal.

Abstract: A method and apparatus for delaying or hastening the “lifespan” of a session in response to detecting (or causing) a session renewal. A “session,” refers to a particular user terminal's right of access to one or more communication channels to exchange data with the base station (and other devices/networks coupled thereto). A session renewal refers to an event or condition that delays the lapse/expiration of the session lifespan (i.e., extends the lifespan) or conversely, an event or condition that causes hastens the lapse of the session lifespan (i.e., causes an earlier lapse of the session). In one embodiment, a session represents the period of time in which a user terminal is registered with a base station and can thus access or attempt to access one or more wireless communication channels to exchange data with the base station.

Abstract: A method and apparatus for mitigating co-channel and inter-channel interference in an antenna array system. According to one aspect, the channel-select filter of a base station or other communication device is modified to detect inter-channel interference on at least one non-primary channel when the transmitter is communicating with a remote user terminal on a primary channel. The spatial characteristic of the interference is determined and used to obtain a weight that mitigates the inter-channel interference. According to another aspect, the spatial characteristic of co-channel and/or inter-channel ghost signal interference caused by a transmitter is determined and used to mitigate the effects of such interference.

Abstract: An emergency call recognition system which is activated when an off-hook situation occurs, which recognizes when an emergency number is dialed with or without the presence of a dial tone, and which provides the caller a communication channel to complete such a call. The present invention is used to give priority to emergency telephone calls. Typically the present invention is used in wireless local loop systems, however the present invention can also be incorporated into a conventional telephone system. The present invention uses an emergency call recognition system to determine if a person is dialing an emergency telephone number. If the emergency call recognition system recognizes a dialed telephone number as an emergency telephone number, then the caller is provided with a communication channel to complete the telephone call. The caller is provided a communication channel even if all of the communication channels are in use. This is accomplished by disconnecting calls that are not of an emergency nature.

Abstract: A method and apparatus for distinguishing between two or more signals, each associated with a particular remote user terminal, in a shared-channel wireless communication system. A communication device, for example, a base station, causes an offset (e.g., a time and/or a frequency offset) between the transmission of first and second uplink signals that simultaneously occupy the same channel and that are transmitted by first and second remote user terminals, respectively. According to one aspect of the invention, the offset is relatively small enough such that the first and second uplink signals remain within the same channel, but relatively large enough such that based on the offset, the communication device may identify that the first uplink signal is associated with the first remote user terminal.

Abstract: A method and apparatus is described for modifying a smart antenna processing strategy determined from a set of signals received at an array of antenna elements of a wireless station, such as a set of weights for processing received antenna signals or forming a set of antenna signals for transmission. The method and apparatus uses the signatures of one or more interferers to produce a modified processing strategy that improves the nulling to the one or more interferers in that, when the modified strategy is applied on the downlink, the transmit signal strength in the direction of the one or more interferers is decreased, and, when the modified strategy is applied on the uplink, the sensitivity to signals from the direction of the one or more interferers is decreased.

Abstract: A method for generating a reference signal from a modulated signal transmitted to a communications station that includes an array of antenna elements and spatial processing means including: separating from the signals received at the antenna elements a copy signal corresponding to the signal transmitted by a particular remote station using an initial spatial weight vector corresponding to the particular remote station; determining from the terminal copy signal a reference signal having substantially the same frequency offset and time alignment as the received antenna signals; and computing a new spatial weight vector by optimizing a cost function, the cost function using the received antenna signals and the reference signal. For demodulation, the method further includes extracting the symbols of the modulated signal.

Abstract: A method for generating a reference signal from a modulated signal transmitted to a communications station that includes an array of antenna elements and spatial processing means including: separating from the signals received at the antenna elements a copy signal corresponding to the signal transmitted by a particular remote station using an initial spatial weight vector corresponding to the particular remote station; determining from the terminal copy signal a reference signal having substantially the same frequency offset and time alignment as the received antenna signals; and computing a new spatial weight vector by optimizing a cost function, the cost function using the received antenna signals and the reference signal. For demodulation, the method further includes extracting the symbols of the modulated signal.

Abstract: An apparatus and method for adaptively producing transmitted signals and processing received signals in a communication system which includes smart antenna array of antenna elements. When processing received signals, the invention modifies an existing processing scheme by incorporating information about a second set of signals for which training or other characteristic information such as a reference is unknown to information about a first set of signals for which characteristic information such as a reference is known, prior to executing the processing scheme. This approach can be used to modify the receive weights which determine the relative weight assigned to the signals received from each of a plurality of antenna elements to take into account the presence of a changing interference environment. This permits an adaptive updating of the receive weights based on the additional information provided by the second set of data.