Abstract: A method and system for cooperative multiple-input multiple output (MIMO) transmission operations in a multicell wireless network. Under the method, antenna elements from two or more base stations are used to from an augmented MIMO antenna array that is used to transmit and receive MIMO transmissions to and from one or more terminals. The cooperative MIMO transmission scheme supports higher dimension space-time-frequency processing for increased capacity and system performance.

Abstract: A system and method of signal detection is provided. A received signal may be correlated with combinations of reference signals, each combination representing a subset of the reference signals, rather than being correlated with each reference signal individually. Once the timing offset has been found, the specific reference signal matching the received signal may be found with a one-dimensional (1D) search. A large 2-D search is thus reduced to a smaller 2-D search followed by a 1-D search. The system and method may be applied to downlink initial acquisition in mobile WiMAX systems.

Abstract: Rapid uplink synchronization is enabled by reducing a 2D search problem to two 1D search problems, which can generally be performed in less time. Advantage is taken of fact that a mobile device sends a ranging code on multiple sub-carriers. Using the assumption that adjacent sub-carriers will have approximately equivalent channel characteristics, phase ambiguity can be removed by differentially combining pairs of adjacent sub-carriers. Once the phase ambiguity is removed, the code, timing, and power level may be determined relatively quickly. In one embodiment, the values of correlations between received signals and possible codes are compared with a threshold.

Abstract: A method and apparatus for subcarrier selection for systems is described. In one embodiment, a method for subcarrier selection for a system employing orthogonal frequency division multiple access (OFDMA) comprises partitioning subcarriers into groups of at least one cluster of subcarriers, receiving an indication of a selection by the subscriber of one or more groups in the groups, and allocating at least one cluster in the one or more groups of clusters selected by the subcarrier for use in communication with the subscriber.

Abstract: A method and apparatus for subcarrier selection for systems is described. In one embodiment, the system employs orthogonal frequency division multiple access (OFDMA). In one embodiment, a method for subcarrier selection comprises a subscriber measuring channel and interference information for subcarriers based on pilot symbols received from a base station, the subscriber selecting a set of candidate subcarriers, providing feedback information on the set of candidate subcarriers to the base station, and receiving an indication of subcarriers of the set of subcarriers selected by the base station for use by the subscriber.

Abstract: Advantage is taken of adaptive allocation techniques by intentionally creating multi-user diversity in an otherwise flat fading environment in order to improve system capacity. In one embodiment, multi-path distortion can be resolved to determine subscriber station (SS) diversity gain. Overall network capacity can be increased by allocating channel assignments to SSs within the network based on determined SS diversity gains. In one embodiment, intentional multi-path distortion is produced by transmitting a signal and a time-delayed version of the signal from a base station (BS).

Abstract: A system and method of wireless communication power control is provided which allows for adjusting power levels without requiring high bandwidth for control. Embodiments allocate subcarriers into unequal power groups, each group having a consistent subcarrier power level. Using interference parameter information from a user, a subcarrier is assigned from a group having adequate power to maintain the user's required power level. In general, users with higher power requirements, such as those near cell boundaries, will be assigned subcarriers from a group having a higher power level. A cell may use a different allocation than a neighbor, so that subcarriers with the highest power level in one cell may not also have the highest power level in a neighboring cell. Such diversity may reduce inter-cell interference of the subcarriers near a cell boundary, since no two subcarriers are transmitted with highest power simultaneously by neighboring base stations.

Abstract: Advantage is taken of the fact that downlink quality is always known at a mobile station. Thus, a base station may use preference information from the mobile station as a basis for assigning a channel, rather than requiring the details of channel conditions. In one embodiment, the base station pre-selects orthogonal beam-forming vectors for subcarriers and broadcasts the channels into different sectors of the region served by base station. The mobile stations then determine a priority (based for example on received quality) order of the codes of the received vectors. This priority order is sent uplink to the base station and the base station then, based on a priority listing of vectors from the mobile station, selects the downlink sub-channel. The vectors may be established with some degree of randomness, or may be based on a desired beam coverage profile.

Abstract: A method and system for cooperative multiple-input multiple output (MIMO) transmission operations in a multicell wireless network. Under the method, antenna elements from two or more base stations are used to from an augmented MIMO antenna array that is used to transmit and receive MIMO transmissions to and from one or more terminals. The cooperative MIMO transmission scheme supports higher dimension space-time-frequency processing for increased capacity and system performance.

Abstract: A method and apparatus for antenna switching, grouping, and channel assignments in wireless communication systems. The invention allows multiuser diversity to be exploited with simple antenna operations, therefore increasing the capacity and performance of wireless communications systems. Channel characteristics indicative of signal reception quality for downlink or bi-directional traffic for each channel/antenna resource combination are measured or estimated at a subscriber. Corresponding channel characteristic information is returned to the base station. Channel characteristics information may also be measured or estimated for uplink or bi-directional signals received at each of multiple receive antenna resources. The base station employs channel allocation logic to assign uplink, downlink and/or bi-directional channels for multiple subscribers based on channel characteristics measured and/or estimated for the uplink, downlink and/or bi-directional channels.

Abstract: A method and apparatus for combining signals of multiple users onto a common channel is disclosed. In one embodiment, the method comprises identifying one or more traffic channels that are of one or more predetermined quality levels to a plurality of subscriber units based on channel profiles of the plurality of subscriber units and transmitting phase modulation multiplexed signals to the plurality of subscriber units through a common set of one or more channels having higher quality than the one or more predetermined quality levels.

Abstract: A method and apparatus for subcarrier selection for systems is described. In one embodiment, a method for subcarrier selection for a system employing orthogonal frequency division multiple access (OFDMA) comprises partitioning subcarriers into groups of at least one cluster of subcarriers, receiving an indication of a selection by the subscriber of one or more groups in the groups, and allocating at least one cluster in the one or more groups of clusters selected by the subcarrier for use in communication with the subscriber.

Abstract: A method and apparatus for subcarrier selection for systems is described. In one embodiment, a method for subcarrier selection for a system employing orthogonal frequency division multiple access (OFDMA) comprises partitioning subcarriers into groups of at least one cluster of subcarriers, receiving an indication of a selection by the subscriber of one or more groups in the groups, and allocating at least one cluster in the one or more groups of clusters selected by the subcarrier for use in communication with the subscriber.

Abstract: A method and apparatus for subcarrier selection for systems is described. In one embodiment, a method for subcarrier selection for a system employing orthogonal frequency division multiple access (OFDMA) comprises partitioning subcarriers into groups of at least one cluster of subcarriers, receiving an indication of a selection by the subscriber of one or more groups in the groups, and allocating at least one cluster in the one or more groups of clusters selected by the subcarrier for use in communication with the subscriber.