Iterative decoding with intentional SNR/SIR reduction
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorJohan Nilsson
Life of this patent
Estimating the term…
Abstract
The excess signal-to-interference ratio (SIR) or the like of a communication channel is determined by repeatedly decoding received information with successively reduced effective SIR. The step size in an outer power control algorithm, for example a Jump Algorithm, such as that commonly used for transmit power control in communication systems can then be adaptively adjusted based on the excess SIR, enabling faster convergence. Decoder hardware already present in a user equipment, such as a mobile telephone or other receiver, can advantageously be used.
Claims22
A method of determining an excess signal-to-interference ratio of a channel in a communication system, comprising the steps of:
- decoding, in a receiver, an information block received through the channel;
- if the information block is decoded correctly, then reducing, in the receiver, an effective signal-to-interference ratio of the received information block and decoding the information block with the reduced effective signal-to-interference ratio;
- and
- determining an excess signal-to-interference ratio of the channel based on the decoding of the information block with the reduced effective signal-to-interference ratio;
- wherein the excess signal-to-interference ratio is related to a difference between the signal-to-interference ratio of the received information block and a minimum signal-to-interference ratio needed for decoding the received information block.
An apparatus for a communication system, comprising:
- a decoder configured to decode received information blocks and to generate respective flag signals that indicate whether respective information blocks are correctly decoded;
- and
- an excess signal-to-interference ratio estimator configured to receive the flag signals, to cause the decoder to decode at least one already decoded information block with a reduced effective signal-to-interference ratio, and to generate an estimate of an excess signal-to-interference ratio based on the decoded information block with the reduced effective signal-to-interference ratio;
- wherein the excess signal-to-interference ratio is related to a difference between the signal-to-interference ratio of the received information block and a minimum signal-to-interference ratio needed for decoding the received information block.
A computer-readable medium containing a computer program for determining an excess signal-to-interference ratio of a channel in a communication system, the computer program implementing the steps of:
- decoding an information block received through the channel;
- if the information block is decoded correctly, then reducing an effective signal-to-interference ratio of the received information block and decoding the information block with the reduced effective signal-to-interference ratio;
- and
- determining an excess signal-to-interference ratio of the channel based on the decoding of the information block with the reduced effective signal-to-interference ratio;
- wherein the excess signal-to-interference ratio is related to a difference between the signal-to-interference ratio of the received information block and a minimum signal-to-interference ratio needed for decoding the received information block.
Dependencies are inferred from the claim text.