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: This invention relates to a method and apparatus for transmitting a downlink signal from a communication station to one or more subscriber units to achieve a desired radiation level over a desired sector (e.g., everywhere), the communication station including an array of antenna elements and one or more signal processors programmed (in the case of programmable signal processors) to weight the downlink signal according to one of a sequence of complex valued weight vectors. The method includes sequentially repeating transmitting the downlink signal, each repetition with a different weight vector from the sequence until all weight vectors in the sequence have been transmitted with. The sequence is designed for achieving the desired radiation level during at least one of the repetitions. In this way, every user in the desired region is transmitted to in the time period.

Abstract: An adaptive method for channel assignment in a cellular multiple access wireless communication system that has a cell station (CS) and a number of subscriber stations augments existing channel assignment protocol and thus is downward compatible with existing time division multiple access (TDMA), frequency division multiple access (FDMA), code division multiple access (CDMA), and spatial division multiple access (SDMA) system protocols. The method adaptively determines the power required for establishing an acceptable quality connection between a subscriber station and the cell station and provides an early warning trial signal for advising existing connections that a new connection is about to be established. The early warning, followed by a pause, provides a basis and a time interval for taking corrective interference action if the trial signal indicates that an unacceptable level of interference will result if the trial connection is established.

Abstract: A wireless communication subscriber unit comprises a radio frequency downconversion stage that produces in-phase and quadrature phase digital samples. A digital signal processor is connected to receive the samples and process them to produce a control channel correlation output and a carrier frequency offset estimate. The acquisition of the control channel is made substantially immune from initial carrier frequency offsets by differential sample encoding the samples. These are input to a correlator whose coefficients are a pre-stored differential sample encoded, decimated and rate expanded version of the known reference sequence. When the the reference sequence is present, the correlator produces a peak output that can be used to detect the presence of the reference sequence. The time position of the peak can be used for time alignment, for signal quality estimation, and to directly obtain a frequency offset estimate.

Abstract: The methods for channel assignment and channel reassignment are suitable for SDMA systems that accommodate the dynamically adaptive spatial channel conditions and allow for more frequent reuse of conventional channels. Three methods for uplink channel assignment are described: a cost function method, a predictive method, and a hierarchical method. The cost function method computes a cost function for each conventional channel based on a weighted correlation matrix of spatial signatures (vectors) of active subscribers. A spatial channel is created for the selected conventional channel if it is in use. The predictive channel assignment method predicts the uplink received power and interference-plus-noise for each conventional channel. Either the conventional channel with the minimum interference-plus-noise level or the channel with the maximal SINR is selected and a spatial channel is also assigned if the selected channel is in use.