Method and apparatus for robust MIMO transmission
A method for operating a user equipment (UE) comprises receiving information about a downlink (DL) transmission transmitted from N RRH >1 RRHs, wherein: N RRH =number of remote radio heads (RRHs), RRH r comprises a group of antenna ports, and r=1, . . . , N RRH ; receiving the DL transmission; and decoding the information about the DL transmission; wherein the DL transmission is based on a scheme that is a combination of a precoding scheme and a diversity scheme, wherein the precoding scheme corresponds to applying an intra-RRH precoder component to antenna ports within an RRH, and wherein the diversity scheme corresponds to applying an inter-RRH diversity component to antenna ports across RRHs.
1 . A user equipment (UE) comprising:
a transceiver configured to receive information about a report associated with N non-zero power (NZP) CSI-RS resources, where N>1; and
a processor operably coupled to the transceiver, the processor, based on the information, configured to:
measure the N NZP CSI-RS resources,
determine an index r* for a reference NZP CSI-RS resource, and
determine delay values, d 1 , . . . d N , relative to the index r* such that d r* =0,
wherein the transceiver is further configured to transmit the report including a first indicator indicating the index r* and a second indicator indicating N−1 intervals,
wherein N−1 delay values {d r : r≠r* and r=1, . . . , N} belong to the N−1 intervals, and
wherein the second indicator is based B bits per interval and a codebook including intervals.
2 . The UE of claim 1 , wherein d r ={tilde over (d)} r −{tilde over (d)} r* , where {tilde over (d)} r is an absolute delay value based on a measurement of a NZP CSI-RS resource r.
3 . The UE of claim 1 , wherein B=1 and the codebook is given by
Bit value
Interval
0
d r ≤ T
1
T < d r
where T is a threshold value determining boundaries of intervals.
4 . The UE of claim 1 , wherein B=2 and the codebook is given by
Bit value
Interval
00
d r ≤ T 1
01
T 1 < d r ≤ T 2
10
T 2 < d r ≤ T 3
11
T 3 < d r
where T 1 , T 2 , T 3 are threshold values determining boundaries of intervals.
5 . The UE of claim 1 , wherein a value of B and the intervals included in the codebook are based on a configuration via radio resource control (RRC) signaling.
6 . The UE of claim 1 , wherein the transceiver is configured to transmit a capability reporting indicating being capable of reporting the delay values.
7 . The UE of claim 1 , wherein:
each of the N NZP CSI-RS resources is a timing reference signal (TRS) resource associated with 1 NZP CSI-RS port and a density of three resource elements (REs) per resource block (RB), and
the report is a standalone aperiodic report.
8 . The UE of claim 1 , wherein a unit of the delay values is in number of orthogonal frequency division multiplexing (OFDM) symbols or in length of a cyclic prefix (CP).
9 . A base station (BS) comprising:
a processor; and
a transceiver operably coupled to the processor, the transceiver configured to:
transmit, to a user equipment (UE), information about a report associated with N non-zero power (NZP) CSI-RS resources, where N>1; and
receive the report including a first indicator indicating an index r* and a second indicator indicating N−1 intervals,
wherein the index r* for a reference NZP CSI-RS resource and delay values, d 1 , . . . d N , are relative to the index r* such that d r* =0,
wherein N−1 delay values {d r : r≠r* and r=1, . . . , N} belong to the N−1 intervals, and
wherein the second indicator is based B bits per interval and a codebook including intervals.
10 . The BS of claim 9 , wherein d r ={tilde over (d)} r −{tilde over (d)} r *, where {tilde over (d)} r is an absolute delay value based on a measurement of a NZP CSI-RS resource r.
11 . The BS of claim 9 , wherein B=1 and the codebook is given by
Bit value
Interval
0
d r ≤ T
1
T < d r
where Tis a threshold value determining boundaries of intervals.
12 . The BS of claim 9 , wherein B=2 and the codebook is given by
Bit value
Interval
00
d r ≤ T 1
01
T 1 < d r ≤ T 2
10
T 2 < d r ≤ T 3
11
T 3 < d r
where T 1 , T 2 , T 3 are threshold values determining boundaries of intervals.
13 . The BS of claim 9 , wherein a value of B and the intervals included in the codebook are based on a configuration via radio resource control (RRC) signaling.
14 . The BS of claim 9 , wherein the transceiver is configured to receive a capability reporting indicating that the UE is capable of reporting the delay values.
15 . The BS of claim 9 , wherein:
each of the N NZP CSI-RS resources is a timing reference signal (TRS) resource associated with 1 NZP CSI-RS port and a density of three resource elements (REs) per resource block (RB), and
the report is a standalone aperiodic report.
16 . The BS of claim 9 , wherein a unit of the delay values is in number of orthogonal frequency division multiplexing (OFDM) symbols or in length of a cyclic prefix (CP).
17 . A method performed by a user equipment (UE), the method comprising:
receiving information about a report associated with N non-zero power (NZP) CSI-RS resources, where N>1;
based on the information:
measuring the N NZP CSI-RS resources,
determining an index r* for a reference NZP CSI-RS resource, and
determining delay values, d 1 , . . . d N , relative to the index r* such that d r* =0; and
transmitting the report including a first indicator indicating the index r* and a second indicator indicating N−1 intervals,
wherein N−1 delay values {d r : r≠r* and r=1, . . . , N} belong to the N−1 intervals, and
wherein the second indicator is based B bits per interval and a codebook including intervals.
18 . The method of claim 17 , wherein d r ={tilde over (d)} r −{tilde over (d)} r *, where {tilde over (d)} r is an absolute delay value based on a measurement of a NZP CSI-RS resource r.
19 . The method of claim 17 , wherein B=1 and the codebook is given by
Bit value
Interval
0
d r ≤ T
1
T < d r
where T is a threshold value determining boundaries of intervals.
20 . The method of claim 17 , wherein B=2 and the codebook is given by
Bit value
Interval
00
d r ≤ T 1
01
T 1 < d r ≤ T 2
10
T 2 < d r ≤ T 3
11
T 3 < d r
where T 1 , T 2 , T 3 are threshold values determining boundaries of intervals.