Method and apparatus for downlink power allocation for 16 QAM modulation scheme in NB-IoT system

1 . A method implemented at a network node in a Narrowband Internet of Thing, NB-IoT, system, comprising:

transmitting downlink power allocation for 16-Quadrature Amplitude Modulation, 16-QAM, modulation scheme to a terminal device in the NB-IoT system, the downlink power allocation indicating data-to-pilot power ratio information to be used for determining Narrowband Physical Downlink Shared Channel, NPDSCH, energy per resource element, EPRE, the data-to-pilot power ratio information comprising a first and a second configured parameter, the first configured parameter comprising a first data-to-pilot power ratio and the second configured parameter comprising a second data-to-pilot power ratio, the NPDSCH EPRE being determined under an assumption that a ratio of NPDSCH EPRE between NPDSCH symbols without a narrowband reference signal, NRS, and without a channel reference signal, CRS, and NPDSCH symbols without a NRS and with a CRS is zero dB.

2 . The method according to claim 1 , wherein the deployment mode is Stand-alone deployment or Guard-band deployment, and wherein the first data-to-pilot power ratio is for NPDSCH symbols without narrowband reference signal, NRS, and the second data-to-pilot power ratio is for NPDSCH symbols with NRS.

3 . The method according to claim 2 , wherein the first and second data-to-pilot power ratios are UE specific and transmitted in Msg4 for random access.

4 . The method according to claim 1 , wherein the deployment mode is In-band deployment, and wherein the data-to-pilot power ratio information comprises a third data-to-pilot power ratio for NPDSCH symbols without NRS and without channel reference signal, CRS, and a fourth data-to-pilot power ratio for NPDSCH symbols with NRS and without CRS, and a fifth data-to-pilot power ratio for NPDSCH symbols without NRS and with CRS.

5 . The method according to claim 4 , wherein the third, fourth and fifth data-to-pilot power ratios are UE specific and transmitted in Msg4 for random access.

6 . The method according to claim 1 , wherein the deployment mode is Stand-alone deployment or Guard-band deployment, and wherein the first data-to-pilot power ratio is for NPDSCH symbols without NRS, and the second data-to-pilot power ratio is for NPDSCH symbols with NRS and the first data-to-pilot power ratio.

7 . The method according to claim 6 , wherein the first configured parameter is UE specific and transmitted in Msg4 for random access; and

the second configured parameter is cell specific and transmitted in System Information Block 2-NB or the second configured parameter is carrier specific and transmitted in System Information Block 22-NB or in Msg4 for random access.

8 . The method according to claim 1 , wherein the deployment mode is In-band deployment, and wherein the data-to-pilot power ratio information comprises a third configured parameter indicating a third data-to-pilot power ratio for NPDSCH symbols without NRS and without CRS, a fourth configured parameter indicating a linear ratio between a fourth data-to-pilot power ratio for NPDSCH symbols with NRS and without CRS and the third data-to-pilot power ratio, and a fifth configured parameter indicating a linear ratio between a fifth data-to-pilot power ratio for NPDSCH symbols without NRS and with CRS and the third data-to-pilot power ratio.

9 . The method according to claim 8 , wherein the third configured parameter is UE specific and transmitted in Msg4 for random access; and

the fourth and fifth configured parameters are cell specific and transmitted in System Information Block 2-NB or the fourth and fifth configured parameters are carrier specific and received in System Information Block 22-NB or in Msg4 for random access.

10 . The method according to claim 1 , wherein the deployment mode is In-band deployment, and wherein the data-to-pilot power ratio information comprises a third configured parameter indicating a third data-to-pilot power ratio for NPDSCH symbols without NRS and without CRS, and a fourth configured parameter indicating a linear ratio between a fourth data-to-pilot power ratio for NPDSCH symbols with NRS and without CRS and the third data-to-pilot power ratio.

11 . The method according to claim 10 , wherein the third configured parameter is UE specific and transmitted in Msg4 for random access; and

the fourth configured parameter is cell specific and transmitted in System Information Block 2-NB or the fourth configured parameter is carrier specific and transmitted in System Information Block 22-NB or in Msg4 for random access.

12 . A network node in a Narrowband Internet of Thing, NB-IoT, system comprising:

one or more processors; and

one or more memories comprising computer program codes,

the one or more memories and the computer program codes configured to, with the one or more processors, cause the network node to:

transmit downlink power allocation for 16-Quadrature Amplitude Modulation, 16-QAM, modulation scheme to a terminal device in the NB-IoT system, the downlink power allocation indicating data-to-pilot power ratio information to be used for determining Narrowband Physical Downlink Shared Channel, NPDSCH, energy per resource element, EPRE, the data-to-pilot power ratio information comprising a first and a second configured parameter, the first configured parameter comprising a first data-to-pilot power ratio and the second configured parameter comprising a second data-to-pilot power ratio, the NPDSCH EPRE being determined under an assumption that a ratio of NPDSCH EPRE between NPDSCH symbols without a narrowband reference signal, NRS, and without a channel reference signal, CRS, and NPDSCH symbols without a NRS and with a CRS is zero dB.

13 . The network node according to claim 12 , wherein the deployment mode is Stand-alone deployment or Guard-band deployment, and wherein the first data-to-pilot power ratio is for NPDSCH symbols without narrowband reference signal, NRS, and the second data-to-pilot power ratio is for NPDSCH symbols with NRS.

14 . A terminal device in a Narrowband Internet of Thing, NB-IoT, system comprising:

one or more processors; and

one or more memories comprising computer program codes,

the one or more memories and the computer program codes configured to, with the one or more processors, cause the terminal device to:

receive downlink power allocation for 16-Quadrature Amplitude Modulation, 16-QAM, modulation scheme from a network node in the NB-IoT system, the downlink power allocation indicating data-to-pilot power ratio information to be used for determining Narrowband Physical Downlink Shared Channel, NPDSCH, energy per resource element, EPRE, the data-to-pilot power ratio information comprising a first and a second configured parameter, the first configured parameter comprising a first data-to-pilot power ratio and the second configured parameter comprising a second data-to-pilot power ratio, the NPDSCH EPRE being determined under an assumption that a ratio of NPDSCH EPRE between NPDSCH symbols without a narrowband reference signal, NRS, and without a channel reference signal, CRS, and NPDSCH symbols without a NRS and with a CRS is zero dB; and

obtain the NPDSCH EPRE determined at least partly based on the data-to-pilot power ratio information.

15 . The terminal device according to claim 14 , wherein the deployment mode is Stand-alone deployment or Guard-band deployment, and wherein the first data-to-pilot power ratio is for NPDSCH symbols without narrowband reference signal, NRS, and the second data-to-pilot power ratio is for NPDSCH symbols with NRS.

16 . A method implemented at a terminal device in a Narrowband Internet of Thing, NB-IoT, system, the method comprising:

receiving downlink power allocation for 16-Quadrature Amplitude Modulation, 16-QAM, modulation scheme from a network node in the NB-IoT system, the downlink power allocation indicating data-to-pilot power ratio information to be used for determining Narrowband Physical Downlink Shared Channel, NPDSCH, energy per resource element, EPRE, the data-to-pilot power ratio information comprising a first and a second configured parameter, the first configured parameter comprising a first data-to-pilot power ratio and the second configured parameter comprising a second data-to-pilot power ratio, the NPDSCH EPRE being determined under an assumption that a ratio of NPDSCH EPRE between NPDSCH symbols without a narrowband reference signal, NRS, and without a channel reference signal, CRS, and NPDSCH symbols without a NRS and with a CRS is zero dB; and

obtaining the NPDSCH EPRE determined at least partly based on the data-to-pilot power ratio information.