US 7,197,692 B2 · Robust erasure detection and erasure-rate-based closed loop power control

Abstract

Techniques for performing erasure detection and power control for a transmission without error detection coding are described. For erasure detection, a transmitter transmits codewords via a wireless channel. A receiver computes a metric for each received codeword, compares the computed metric against an erasure threshold, and declares the received codeword to be “erased” or “non-erased”. The receiver dynamically adjusts the erasure threshold based on received known codewords to achieve a target level of performance. For power control, an inner loop adjusts the transmit power to maintain a received signal quality (SNR) at a target SNR. An outer loop adjusts the target SNR based on the status of received codewords (erased or non-erased) to achieve a target erasure rate. A third loop adjusts the erasure threshold based on the status of received known codewords (“good”, “bad”, or erased) to achieve a target conditional error rate.

Claims33

Dependent claims

A method of performing erasure detection in a communication system, comprising:

obtaining received codewords for codewords transmitted via a wireless channel, each transmitted codeword being a block of coded or uncoded data, and each received codeword being a noisy version of a transmitted codeword;
computing a metric for each of the received codewords;
comparing the computed metric for each received codeword against an erasure threshold;
declaring each received codeword to he an erased codeword or a non-erased codeword based on a comparison result for the received codeword;
and
dynamically adjusting the erasure threshold to achieve a target level of performance for erasure detection.

3 more elements

A method of performing power control for a transmission sent via a wireless channel in a wireless communication system, comprising:

obtaining received codewords for codewords transmitted in the transmission, each transmitted codeword being a block of coded or uncoded data, and each received codeword being a noisy version of a transmitted codeword;
determining a status of each received codeword as being an erased codeword or a non-erased codeword based on a metric computed for the received codeword and an erasure threshold;
adjusting a target signal quality (SNR) based on the status of each received codeword, wherein transmit power for the transmission is adjusted based on the target SNR;
obtaining received known codewords for known codewords transmitted via the wireless channel, each known codeword being a block of a known data, and each received known codeword being a noisy version of a transmitted known codeword;
determining a status of each received known codeword as being a good codeword, a bad codeword, or an erased codeword, a good codeword being a received known codeword deemed to be a non-erased codeword and decoded correctly, and a bad codeword being a received known codeword deemed to be a non-erased codeword but decoded in error;
and
adjusting the erasure threshold based on the status of each received known codeword.

4 more elements

An apparatus operable to perform power control for a transmission sent via a wireless channel in a wireless communication system, comprising:

a data processor operative to obtain received codewords for codewords transmitted in the transmission, each transmitted codeword being a block of coded or uncoded data, and each received codeword being a noisy version of a transmitted codeword,
determine a status of each received codeword as being an erased codeword or a non-erased codeword based on a metric computed for the received codeword and an erasure threshold,
obtain received known codewords for known codewords transmitted via the wireless channel, each known codeword being a block of a known data, and each received known codeword being a noisy version of a transmitted known codeword, and
determine a status of each received known codeword as being a good codeword, a bad codeword, or an erased codeword, a good codeword being a received known codeword deemed to be a non-erased codeword and decoded correctly, and a bad codeword being a received known codeword deemed to be a non-erased codeword but decoded in error;
and
a controller operative to
adjust a target signal quality (SNR) based on the status of each received codeword, wherein transmit power for the transmission is adjusted based on the target SNR, and adjust the erasure threshold based on the status of each received known codeword.

4 more elements

Dependencies are inferred from the claim text.

Robust erasure detection and erasure-rate-based closed loop power control

Life of this patent

Robust erasure detection and erasure-rate-based closed loop power control

Life of this patent

Abstract

Claims33