Method and device for feeding back ACK/NACK (Acknowledgement/Negative Acknowledgement) information

Abstract

The invention relates to the communication field and discloses a method and device for feeding back ACK/NACK (Acknowledgement/Negative Acknowledgement) information, which is used for improving the system performance of an LTE-A (Long Term Evolution-Advanced) system. By combining the characteristic that the LTE-A system can use the carrier aggregation technology, the method redesigns a mapping relationship between ACK/NACK information and ACK/NACK feedback bits, and the ACK/NACK feedback bits are used for indicating the number of downlink subframes correctly received by UE (User Equipment) rather than the number of data packets correctly received. Thus, the invention can accurately reflect the receiving situations of multiple downlink subframes in multiple downlink carriers based on the limited K-bit ACK/NACK feedback bits when the ACK/NACK feedback information and other uplink feedback information are simultaneously transmitted through a PUCCH (Physical Uplink Control Channel), and can minimize the mistaken judgments of a base station on data receiving situations of user terminals caused by the many-to-one mapping of the ACK/NACK feedback bits so as to avoid unnecessary retransmission, thereby improving the transmission performance of the system.

Description

technical field [0001] The invention relates to the communication field, in particular to a method and device for feeding back ACK / NACK information. Background technique [0002] In the LTE-A (Long Term Evolution-Advanced, Advanced Long-Term Evolution) system, referred to as the LTE-A system, in order to support a wider system bandwidth than the LTE system, such as 100MHz, the following two spectrum allocation methods are usually used: [0003] One is to directly allocate the spectrum with a bandwidth of 100M in the form of a single spectrum, specifically as figure 1 shown. [0004] The other is to use spectrum aggregation to aggregate the spectrum allocated to the existing system into 100M bandwidth for system use. Such as figure 2 As shown, when the spectrum aggregation method is adopted, the uplink and downlink carriers in the LTE-A system can be configured asymmetrically, that is, the UE (User Equipment, user terminal) can occupy N1≥1 carriers for downlink transmissi...

AI Technical Summary

Problems solved by technology

[0022] In the LTE Rel-8 system, since the ACK / NACK feedback bits b(0) and b(1) have only 2 bits and only contain 4 states, the number of ACKs indicating the receiving state of the data packet may contain the Therefore, there is a many-to-one mapping between the data packet receiving state and the 2-bit ACK / NACK feedback bit b(0), b(1), as shown in Table 2, which means that the UE correctly receives one or The b(0) and b(1) mapped out by the state of 4 or 7 data packets are both [1, 1]. When the base station receives the ACK / NACK feedback bit as [1, 1], if the base station actually only If 1 data packet is scheduled, the base station can clearly judge that the UE correctly received 1 data packet, but if the base station actually schedules 4 data packets, the base station cannot determine whether the UE correctly received 1 data packet or 4 data packets or It is 7 data packets, so it will affect the data retransmission of the base station

[0023] In the LTE-A system, due to the use of carrier aggregation technology, the number of bits of ACK / NACK information that needs to be fed back is large, and reusing the mapping relationship in LTE Rel-8 will result in more many-to-one mapping relationships. Therefore, The mapping relationship between ACK / NACK information and ACK / NACK feedback bits formulated in the LTE Rel-8 system is no longer applicable to the LTE-A system. Correspondingly, the ACK / NACK feedback bits in the LTE Rel-8 system are related to the SR The method of simultaneous transmission of information and / or periodic CSI is also no longer applicable to the LTE-A system and needs to be redesigned

Images