A method and apparatus for allocating subcarriers in an orthogonal frequency division multiple access (OFDMA) system is described. In one embodiment, the method comprises allocating at least one diversity cluster of subcarriers to a first subscriber and allocating at least one coherence cluster to a second subscriber.

Ofdma with adaptive subcarrier-cluster configuration and selective loading

A method and apparatus for subcarrier selection for systems is described. In one embodiment, a method for subcarrier for a system employing orthogonal frequency division multiple access (OFDMA) comprises partitioning subcarriers (101) into groups of at least one cluster of subcarriers (102), receiving an indication of a selection by the subscriber of one or more groups (103) 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 (104, 105).

Multi-carrier communications with group-based subcarrier allocation

Multi-carrier communications with adaptive cluster configuration and switching

An apparatus and process for allocating carriers in a multi-carrier system is described. In one embodiment, the process comprises determining a location (E, D, C, B, A; fig. 6) of a subscriber (520) with respect to a base station (510), selecting carriers from a band of carriers to allocate to the subscriber (520) according to the location of the subscriber with respect to the base station (510), and allocating selected carriers to the subscriber (520).

Method and apparatus for adaptive carrier allocation and power control in multi-carrier communication systems

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.

Method and system for switching antenna and channel assignments in broadband wireless networks

We consider adaptive coded modulation for systems using QPSK/8PSK/16QAM constellations with a decision-feedback equalizer for slow frequency-selective fading channels. We investigate several potential channel-quality metrics that could be used to choose the correct coding and modulation scheme. We then present a threshold-adaptive algorithm that is especially useful for channels with a wide range of multipath profiles.

Xiaodong Li

Papers

Adaptive coded modulation over slow frequency-selective fading channels