Method and base station for detecting a HARQ-ACK codeword

摘要

A method in a base station for detecting a HARQ-ACK codeword comprised in a signal received from a UE is provided. The base station knows HARQ-ACK codewords being possible to detect. The base station receives (401) a signal from the UE comprising a modulation symbol. The base station estimates (402) a SNR value for the received signal, and calculates (403) soft values for the modulation symbol. When the SNR value is lower than a predetermined threshold value and when the modulation symbol of the received signal comprises more than two bits per modulation symbol, the base station uses a first mode. The first mode comprises correlating (405) only the two first calculated soft values for the modulation symbol with the one or more known possible HARQ-ACK codewords. In other cases, i.e. when the first mode is not used, the base station uses a second mode. The second mode comprises correlating (408) all calculated soft values for the modulation symbol with the known possible HARQ-ACK codewords.

主权项

1. A method in a base station for detecting a Hybrid Automatic Repeat Request-ACKnowledgement (HARQ-ACK) codeword comprised in a signal received from a user equipment, which user equipment is arranged to communicate with the base station over a radio channel, which base station has knowledge of one or more HARQ-ACK codewords that are possible to detect in the received signal, the method comprising:
receiving a signal from the user equipment over the radio channel, which signal comprises a modulation symbol, estimating a Signal to Noise Ratio (SNR) value for the received signal, which SNR value will be used to decide whether a first mode or a second mode shall be used for detecting the HARQ-ACK codeword in the received signal, calculating soft values for the modulation symbol in the received signal, when the estimated SNR value is lower than or equal to a predetermined threshold value and when the modulation symbol of the received signal comprises more than two bits per modulation symbol, using the first mode for detecting the HARQ-ACK codeword in the received signal, which first mode comprises correlating a subset of the soft values for the modulation symbol in the received signal with the one or more known possible HARQ-ACK codewords, and otherwise, using the second mode for detecting the HARQ-ACK codeword in the received signal, which second mode comprises correlating a set of the soft values for the modulation symbol in the received signal with the one or more known possible HARQ-ACK codewords.