Methods and apparatus for generating, communicating, and/or using information relating to self-noise

Abstract

A wireless terminal measures the received power of a tone corresponding to an intention base station null output, measures the received power of pilot signals, and determines a signal to noise ratio of the received pilot signal. The wireless terminal calculates a downlink signal to noise ratio saturation level representative of the SNR of a received downlink signal that the wireless terminal would measure on a received signal transmitted by the base station at infinite power. The calculated downlink signal to noise ratio saturation level is a function of the determined interference power, the measured received pilot signal power, and the determined pilot signal SNR. A report is generated corresponding to one of a plurality of quantized levels, the selected quantized level being the closest representation to the calculated downlink signal to noise ratio saturation level. The generated report is communicated using a dedicated control channel segment in a predetermined uplink timing structure.

Description

RELATED APPLICATIONS[0001]The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 60 / 752,973, filed on Dec. 22, 2005, titled “COMMUNICATIONS METHODS AND APPARATUS”, which is hereby expressly incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to methods and apparatus of wireless signaling and, more particularly, to methods and apparatus for generating, transmitting, and / or using a report relating to and / or providing self noise information.BACKGROUND[0003]In cellular wireless systems, base stations often need to communicate user data / information to multiple wireless terminals simultaneously. In the downlink, the link from the base station (BS) to the wireless terminals (WTs), an important problem is the allocation of base station transmitter power to the different WTs being served simultaneously by the same BS. Each BS typically has a total transmit power budget available for all downlink communication, and this power...

AI Technical Summary

Benefits of technology

[0014]The present invention is directed to, among other things, a method of operating a first communications device, e.g., a wireless terminal, including a receiver operating in the presence of self-noise. In one embodiment the method includes receiving first and second signals from a second communications device, e.g., a base station, said first and second signals having been transmitted at first and second power levels, said first and second power levels being different; performing a first noise measurement on the first received signal; performing a second noise measurement of the second received signal; and communicating noise measurement information corresponding to the first and second received signals to the second communications device. In some embodiments, the communicated information provides information indicating how a SNR at the receiver varies as a function of the transmit power of the second device. This allows the second communications device to know or determine the self-noise saturation SNR level of the first communications device.

Problems solved by technology

In the downlink, the link from the base station (BS) to the wireless terminals (WTs), an important problem is the allocation of base station transmitter power to the different WTs being served simultaneously by the same BS.

One problem in realizing the potential of the multiple access OFDM downlink, is that a base station needs to perform appropriate power allocation.

If too little power is allocated, the decoding of the segment will likely fail and need re-transmission.

If the power allocated for is excessive, it means that power was wasted and that wasted power could have been used for the other WTs being serviced by the base station.

However, in practice, the WT receiver processing introduces errors, such as channel estimation inaccuracies, phase jitter, and timing and frequency offsets.

These errors typically scale with the received power, and effectively add a signal-dependent component to the noise.

In the presence of self-noise, the WT can no longer simply report the SNR at a single power level and expect the base station to be able to determine correct transmit power corresponding to different data rate options.

From a single SNR measurement, the BS cannot separate the self-noise and external noise components, and therefore, cannot accurately extrapolate the power required to obtain any other SNR.

These systems offer rates at high SNRs (often in excess of 20 dB) where the self-noise component can be significant.

Also, as these services are to be offered in mobile, fading environments, or in long range applications with significant delay spread, the self-noise component will become more pronounced.

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