Patent ID: 7656969
Filing Date: 2010-02-02
Classification: H04B,H04L,H04W,Y02D

Abstract:
1. A wireless broadband communications system, comprising: at least one transmitter; at least two transmit antennas, the transmitter and said at least two transmit antennas being configured and arranged to transmit at least one first signal over at least one communications channel, wherein said at least one signal comprises at least two non-overlapping sets of pilot signals and is capable of carrying at least one payload of information; at least one receiver, and at least two receive antennas, wherein the receiver and said at least two receive antennas are configured and arranged to receive said at least one first signal transmitted over said at least one channel, wherein the receiver is operative to determine channel state information from said at least one received signal, to select between a single payload mode and a dual payload mode of operation and at least one transmit characteristic based at least in part upon said channel state information, and to provide an indication of said payload mode and transmit characteristic selections to the transmitter, wherein the transmitter and said at least two transmit antennas are operative to transmit at least one second signal over said at least one channel in accordance with said payload mode and transmit characteristic selections, wherein: channel impulse responses are represented by channel state matrices in which elements of the matrices correspond to signals propagating along different paths between the transmit and receive antennas, selection of a transmission modulation mode and either the single or dual payload mode(“modulation mode/payload mode combination”) uses a set of variable data and a set of constant data, the set of variable data includes a current transmission modulation mode, average vector error (“ave_vec_err”) measurement values for the single and dual payload modes, a modulation mode transition-up margin (“up_margin”) value, a modulation mode transition-down margin (“down_margin”) value, mean square of magnitudes of determinants of channel state matrices (“mean_sqr_A”), and an imbalance estimate value (“mean_sqr_B”) calculated from the channel state matrices, and the set of constant data includes a modulation mode transition-up/vector error threshold (“up_margin_vec_err_thresh”) value, a modulation mode transition-down/vector error threshold (“down_margin_vec_err_thresh”) value, and a threshold value corresponding to mean_sqr_A (“thresh_mean_sqr_A”), the up_margin_vec_err_thresh value is associated with each transmission modulation mode below a modulation mode corresponding to a maximum rate of data transmission, the up_margin_vec_err_thresh value is equal to the average measured vector error for a given modulation mode when, for the same channel, the channel would be at a specified threshold of operation if the system were operating in the next modulation mode, the down_margin_vec_err_thresh value is associated with each transmission modulation mode above the modulation mode corresponding to a minimum rate of data transmission, the down_margin_vec_err_thresh value is equal to the average measured vector error when the current modulation mode is at the specified threshold of operation.