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Techniques to select a suitable transmission mode for a data transmission in a multi-channel communication system with multiple transmission channels having varying SNRs. In one method, an SNR estimate is initially obtained for each of multiple transmission channels used to transmit a data stream. A

Techniques to select a suitable transmission mode for a data transmission in a multi-channel communication system with multiple transmission channels having varying SNRs. In one method, an SNR estimate is initially obtained for each of multiple transmission channels used to transmit a data stream. An average SNR and an unbiased variance are then computed for the SNR estimates for the multiple transmission channels. A back-off factor is determined, for example, based on the SNR variance and a scaling factor. An operating SNR for the transmission channels is next computed based on the average SNR and the back-off factor. The transmission mode is then selected for the data stream based on the operating SNR. The selected transmission mode is associated with a highest required SNR that is less than or equal to the operating SNR. The method may be used for any system with multiple transmission channels having varying SNRs.

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What is claimed is: 1. A method of determining transmission modes for data transmission in a multi-channel communication system, comprising:obtaining a signal-to-noise ratio (SNR) estimate for each of a first plurality of transmission channels with varying SNRs used for a first data stream;computing

What is claimed is: 1. A method of determining transmission modes for data transmission in a multi-channel communication system, comprising:obtaining a signal-to-noise ratio (SNR) estimate for each of a first plurality of transmission channels with varying SNRs used for a first data stream;computing a first average SNR and a first SNR variance based on SNR estimates for the first plurality of transmission channels;determining a first back-off factor as a product of a first scaling factor with the first SNR variance, which accounts for frequency selectivity of a communication link associated with the first plurality of transmission channels;calculating a first operating SNR value for the first plurality of transmission channels by subtracting the first back-off factor from the first average SNR value;determining a first transmission mode for the first data stream based on the first operating SNR value, wherein the first transmission mode indicative of a particular data rate, a particular coding scheme, and a particular modulation scheme employed for data transmission;utilizing the first transmission mode to transmit the first data stream over each of the first plurality of transmission channels;obtaining an SNR estimate for each of a second plurality of transmission channels with varying SNRs used for a second data stream, wherein the first plurality of transmission channels is for a first antenna and the second plurality of transmission channels is for a second antenna associated with the multi-channel communication system;computing a second average SNR and a second SNR variance based on the SNR estimates for each of the second plurality of transmission channels;determining a second back-off factor as a product of a second scaling factor with the second SNR variance, which accounts for frequency selectivity of a communication link associated with the second plurality of transmission channels;calculating a second operating SNR value for the second plurality of transmission channels by subtracting the second back-off factor from the second average SNR value;determining a second transmission mode for the second data stream based on the second operating SNR value, wherein the second transmission mode indicative of a particular data rate, a particular coding scheme, and a particular modulation scheme employed for data transmission; andutilizing the second transmission mode to transmit the second data stream over each of the second plurality of transmission channels,wherein the determining the first and the second transmission mode includes computing transmission modes for a multiple-input multiple-output (MIMO) communication system, andwherein the obtaining the SNR estimates for the first plurality of transmission channels includes obtaining the SNR estimates for a first spatial channel by decomposition of a first channel response matrix and the obtaining the SNR estimates for the second plurality of transmission channels includes obtaining the SNR estimates for a second spatial channel by decomposition of a second channel response matrix.