FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to methods, devices, apparatuses and computer readable storage media for Uplink Control Information (UCI) design.

BACKGROUND

In 3GPP New Radio (NR) Rel-15 and 16, a compression mechanism has been introduced to reduce the overhead in reporting Channel State Information (CSI) from UEs to the Base Transceiver Station (BTS), which is required to operate Multi-User Multiple Input Multiple Output (MU-MIMO) in the downlink. The mechanism consists in two DFT-based operations in the spatial domain and in the frequency domain. These operations are applied to each layer for rank indicators (RI) from 1 to 4. The CSI message may comprise a Channel Quality Indicator (CQI) and a Precoding Matrix Indicator (PMI). The CQI may be obtained from an estimate of the expected SINR after decoding of a codeword multiplexed across the reported spatial layers and PMI may comprise a set of complex-valued precoding weights that are needed to achieve that CQI. Both CQI and PMI parameters are reported per sub-band. The PMI is represented by a matrix for each reported layer, each containing as many column vectors as the number of sub-bands. The SD and FD compression operations are applied to these PMI matrices across their rows and columns respectively.

An important aspect of CSI signalling for MU-MIMO is the arrangement of the components of the compressed PMI in uplink control information (UCI) message. In a conventional way, this message may be organised in two parts, namely “UCI part 1” and “UCI part 2”. The “UCI part 1” may comprise the CQI information and the parameters needed to determine the payload size of the “UCI part 2”. The “UCI part 1” transmitted in the Physical Uplink Control Channel (PUCCH) may have a very short and fixed-size payload and may be encoded with very strong forward error correction code to guarantee error-free decoding. The “UCI part 2” may comprise the bulk of compressed PMI and be transmitted in the Physical Uplink Shared Channel (PUSCH), hence it has the same error protection as data.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for Uplink Control Information (UCI) design.

In a first aspect, there is provided a method. The method comprises determining, at a terminal device, a matrix comprising a set of non-zero linear combination coefficients for quantizing a channel between the terminal device and a network device, the matrix having spatial components and frequency components; shifting the frequency components of the matrix circularly, such that a target coefficient of the set of non-zero linear combination coefficients is located in a frequency component with a predetermined index of the frequency components in a shifted matrix; generating a first indication indicating the spatial component associated with the target coefficient in the matrix; and transmitting, to the network device, uplink control information comprising the first indication.

In a second aspect, there is provided a method. The method comprises receiving, at a network device and from a terminal device, uplink control information comprising a first indication, the first indication indicating spatial components associated with a target coefficient in a matrix comprising a set of non-zero linear combination coefficients for quantizing a channel between the terminal device and the network device, the matrix having the spatial components and frequency components; and determining state information of the channel based on the uplink control information.

In a third aspect, there is provided a device. The device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the device at least to determine, at a terminal device, a matrix comprising a set of non-zero linear combination coefficients for quantizing a channel between the terminal device and a network device, the matrix having spatial components and frequency components; shift the frequency components of the matrix circularly, such that a target coefficient of the set of non-zero linear combination coefficients is located in a frequency component with a predetermined index of the frequency components in a shifted matrix; generate a first indication indicating the spatial component associated with the target coefficient in the matrix; and transmit, to the network device, uplink control information comprising the first indication.

In a fourth aspect, there is provided a device. The device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the device at least to receive, at a network device and from a terminal device, uplink control information comprising a first indication, the first indication indicating spatial components associated with a target coefficient in a matrix comprising a set of non-zero linear combination coefficients for quantizing a channel between the terminal device and the network device, the matrix having the spatial components and frequency components; and determine state information of the channel based on the uplink control information.

In a fifth aspect, there is provided an apparatus comprises means for determining, at a terminal device, a matrix comprising a set of non-zero linear combination coefficients for quantizing a channel between the terminal device and a network device, the matrix having spatial components and frequency components; means for shifting the frequency components of the matrix circularly, such that a target coefficient of the set of non-zero linear combination coefficients is located in a frequency component with a predetermined index of the frequency components in a shifted matrix; means for generating a first indication indicating the spatial component associated with the target coefficient in the matrix; and means for transmitting, to the network device, uplink control information comprising the first indication.

In a sixth aspect, there is provided an apparatus comprising means for receiving, at a network device and from a terminal device, uplink control information comprising a first indication, the first indication indicating spatial components associated with a target coefficient in a matrix comprising a set of non-zero linear combination coefficients for quantizing a channel between the terminal device and the network device, the matrix having the spatial components and frequency components; and means for determining state information of the channel based on the uplink control information.

In a seventh aspect, there is provided a computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method according to the first aspect.

In an eighth aspect, there is provided a computer readable medium having a computer program stored thereon which, when executed by at least one processor of a device, causes the device to carry out the method according to the second aspect.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

