High-order multiple-user multiple-input multiple-output operation for wireless communication systems

Abstract

Methods and apparatuses schedule resources and identify resource scheduling in a MU MIMO wireless communication system. A method for identifying resource scheduling for a ue includes receiving downlink control information; identifying, from the downlink control information, one or more DM-RS ports assigned to the ue and a pdsch epre to DM-RS epre ratio; and identifying data intended for the ue in a resource block in a downlink subframe using the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio. A method for scheduling resources includes identifying one or more DM-RS ports to assign to a ue and a pdsch epre to DM-RS epre ratio for identifying data intended for the ue in a resource block in a downlink subframe; and including an indication of the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio in downlink control information.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY

where C_init is the initialization value of the scrambling sequence, N_ID^cell is the cell identifier (ED) and n_SCID is the scrambling code. The scrambling sequence itself can be generated according to 3GPP TS 36.211 §6.10.3.1. As each DM-RS port has two scrambling IDs (N_ID^cell), two semi-orthogonal DM-RS resources are provided and the total number of users that can be simultaneously served by the base station is 16, with a rank 1 transmission to each user. If the cell identifier in the DM-RS pseudorandom sequence generation initialization is replaced with a parameter “x”, which is configurable by the network entity, (e.g. by an RRC) then the total number of users that can be simultaneously served by the base station can be further increased.

FIGS. 4A-C illustrate examples of orthogonal or semi-orthogonal MU-MIMO multiplexing in accordance with embodiments of the present disclosure. FIG. 4A illustrates a frequency resource for two RS orthogonally or semi-orthogonally multiplexed to provide one reference signal per UE to two UEs and the corresponding multiplexing of the frequency resources for the data intended for the respective UEs. FIG. 4B illustrates two frequency resources used for two RSs for three UEs with data intended for the respective UEs orthogonally or semi-orthogonally multiplexed among the frequency resources for data. FIG. 4C illustrates two frequency resources for eight RSs orthogonally or semi-orthogonally multiplexed to provide reference signals to eight UEs. The data for the UEs is orthogonally or semi-orthogonally multiplexed among the frequency resources for data. In various embodiments, the network entity may assign the DM-RS resources such that UEs with relatively higher inter-user interference have orthogonal DM-RS resources, while UEs with relatively low inter-user interference may be assigned DM-RS resources that are semi-orthogonal.

FIG. 5 illustrates a signaling pattern for MU-MIMO multiplexing using ports of a same CDM group in accordance with various embodiments of the present disclosure. To facilitate MU-MIMO multiplexing between UEs, various embodiments include assignment of ports belonging to a same CDM group (e.g., ports 11 and 13). In other words, in one physical resource block (PRB), the DM-RS ports used by the network entity for MU-MIMO multiplexing may include only ports of the same CDM group, for example, ports 7, 8, 11, and 13 as illustrated in FIG. 5, while the ports belonging to different CDM group (e.g., ports 9, 10, 12, and 14) are not transmitted, and the corresponding REs may be used for data transmission. An additional advantage of this design is that the overhead for the DM-RS may be reduced.

Additionally, this design also does not impact the PDSCH EPRE to DM-RS EPRE ratio assumed by legacy UEs (e.g., assumed to be 0 dB). The high order MU-MIMO UEs can also assume that the PDSCH EPRE to DM-RS EPRE ratio is 0 dB. For example, FIG. 6 illustrates an example of orthogonal or semi-orthogonal MU-MIMO multiplexing where the PDSCH EPRE to DM-RS EPRE ratio is assumed to be 0 dB in accordance with embodiments of the present disclosure.

In some embodiments, the resource elements for the UEs may be multiplexed using only two ports (e.g., ports 7 and 8), for example, by assigning different scrambling ID for different UEs assigned the same DM-RS port.

Additionally, in various embodiments, DM-RS ports of CDM group 2 may be used for MU-MIMO multiplexing by the network entity if one or more DM-RS ports of CDM group 1 are also used. In one example, if a UE is assigned only port(s) from CDM group 2, the UE may assume that the REs corresponding to the DM-RS of CDM group 1 are not used for data transmission. This use of DM-RS ports of CDM group 2 also enables a UE to be multiplexed with a legacy UE that is assigned with rank that is greater than 2.

In various embodiments, the network entity may provide control signaling to indicate the scheduling of the resources to support the high-order MU-MIMO operations of the present disclosure. The control signaling provided by the network entity may include at least one and possibly more of: the DM-RS Port(s) assigned to the UE; a physical downlink shared channel (PDSCH) energy per resource element (EPRE) to DM-RS EPRE ratio; whether rate matching around unassigned port(s) in another DM-RS CDM group should be applied; and the existence of interfering UEs.

The PDSCH EPRE to DM-RS EPRE ratio is a ratio of the average power of the signal intended for the UE compared with the average power of another signal that may be present in the resource element. For example, a signal in a resource element intended for a UE may be separated and distinguished from a signal in the same resource element that is intended to convey different information than the other signal based on the PDSCH EPRE to DM-RS EPRE ratio (e.g., a −3 dB average power difference between the signals). Even if UE is assigned 2 or less than 2 layers, other DM-RS CDM groups may be assigned to other UEs. If the UE is not assigned any ports belonging to a DM-RS CDM group, the control signaling may indicate whether the UE should assume data is mapped to the REs of that DM-RS CDM group or not (e.g., whether rate matching around unassigned port(s) in another DM-RS CDM group should be applied). The control signaling may also indicate the existence of interfering UEs. For example, the control signaling from the network entity may indicate whether the DM-RS port(s) not assigned to the UE is assigned to another UE. The explicit signaling of interfering UEs may avoid the need for the UE to use blind detection of the existence of an interfering UE.

In various embodiments, the network entity may enable dynamic single user (SU) and MU scheduling. For example, a base station may provide dynamic control signaling (e.g. provided in a downlink control information (DCI) format) which can be supported to indicate whether SU or MU scheduling is being used.

Indicating the DM-RS ports, the PDSCH EPRE to DM-RS EPRE ratio, rate matching, and the existence of interfering UEs may require significant signaling overhead to fully support and enable MU-MIMO operation. Various embodiments utilize signaling techniques to reduce the signaling overhead associated with implementing the MU-MIMO operation of the present disclosure. For example, in some embodiments, the network entity may only assign each MU-MIMO UE up to rank 2 spatial multiplexing and may jointly code the power offset and rate matching. For example, a single bit field may jointly indicate the power offset and rate matching assumption. In one illustrative embodiment, the network entity may introduce or reuse one bit from an existing bit in the DCI format to indicate the power offset and rate matching, for example, as shown in Table 1 below. In another example, this information can be jointly encoded with other fields, for example, a bit field used to indicate antenna port(s), scrambling identity, and/or number of layers may also be used to jointly indicate the power offset and/or rate matching assumption.

TABLE 1
Power offset and rate matching signaling
	PDSCH EPRE	Rate matching
Signaled	to DM-RS	around not assigned
value	EPRE ratio	CDM group
0	0 dB	No
1	−3 dB	Yes

In some embodiments, if the UE is assigned port(s) that are not DM-RS ports 7 and/or 8, the UE may assume that the PDSCH EPRE-to-DM-RS EPRE ratio of −3 dB and rate matching applied when receiving PDSCH in the assigned resource blocks. If UE is assigned ports 7 and/or 8, the network entity may provide additional signaling to indicate what PDSCH EPRE-to-DM-RS EPRE ratio and rate matching are to be assumed.

In other embodiments, if UE is assigned port(s) that do not belong to DM-RS CDM group 1, the UE may assume a PDSCH EPRE-to-DM-RS EPRE ratio of −3 dB and rate matching around REs belonging to DM-RS CDM group 1 when receiving PDSCH in the assigned resource blocks. If UE is only assigned ports in CDM group 1 and not in CDM group 2, the network entity may provide additional signaling to indicate what PDSCH EPRE to DM-RS EPRE ratio and whether rate matching around REs belonging to CDM group 2 are to be assumed. In these embodiments, DM-RS CDM group 1 is implicitly prioritized for assignment.

In one example, the baseline DCI format design can be similar to DCI format 2C in release 10, with at least the following exception: the bit field used for joint coding of antenna port(s), scrambling identity and number of layers is extended to allow enhanced support for MU-MIMO (see e.g., Tables 2 and 3 where 5 bits are used). One example of the DM-RS mapping as described above is also illustrated in these tables. For example, for one codeword transmission, the power offset and rate matching can be indicated by an existing field reserved for the second codeword, (e.g. the New Data Indicator (NDI) of the disabled TB). One example of the extension of bit field used for joint coding of antenna port(s), scrambling identity, and number of layers for one codeword transmission is illustrated in Table 2 below.

TABLE 2

One Codeword:
Codeword 0 enabled,
Codeword 1 disabled
Value Message

0     1 layer, port 7, nSCID = 0
1     1 layer, port 7, nSCID = 1
2     1 layer, port 8, nSCID = 0
3     1 layer, port 8, nSCID = 1
4     2 layers, ports 7-8, nSCID = 0
5     3 layers, ports 7-9 (−3 dB PO)
6     4 layers, ports 7-10 (−3 dB PO)
7     1 layer, port 9, nSCID = 0
8     1 layer, port 9, nSCID = 1
9     1 layer, port 10, nSCID = 0
10    1 layer, port 10, nSCID = 1
11    1 layer, port 11, nSCID = 0
12    1 layer, port 11, nSCID = 1
13    1 layer, port 12, nSCID = 0
14    1 layer, port 12, nSCID = 1
15    1 layer, port 13, nSCID = 0
16    1 layer, port 13, nSCID = 1
17    1 layer, port 14, nSCID = 0
18    1 layer, port 14, nSCID = 1
19    2 layers, ports 7-8, nSCID = 1
20    2 layers, ports 9-10, nSCID = 0
21    2 layers, ports 9-10, nSCID = 1
22    2 layers, ports 11, 13, nSCID = 0
23    2 layers, ports 11, 13, nSCID = 1
24    2 layers, ports 12, 14, nSCID = 0
25    2 layers, ports 12, 14, nSCID = 1
26    Reserved
27    Reserved
28    Reserved
29    Reserved
30    Reserved
31    Reserved

For more than two layer transmissions, if only −3 dB power offset is supported, the bit to indicate power offset value may be ignored by the UE. For two-codeword transmission, the power offset and rate matching assumption can also be jointly encoded with the antenna port(s), scrambling identity, and number of layers as there are enough reserved bits, as shown in Table 3 below. One example of the extension of bit field used for joint coding of antenna port(s), scrambling identity, and number of layers for two codeword transmission is illustrated in Table 3.

TABLE 3

Two Codewords:
Codeword 0 enabled,
Codeword 1 enabled
Value Message

0     2 layers, ports 7-8, nSCID = 0 (0 dB
      PO)
1     2 layers, ports 7-8, nSCID = 1 (0 dB
      PO)
2     3 layers, ports 7-9 (−3 dB PO)
3     4 layers, ports 7-10 (−3 dB PO)
4     5 layers, ports 7-11 (−3 dB PO)
5     6 layers, ports 7-12 (−3 dB PO)
6     7 layers, ports 7-13 (−3 dB PO)
7     8 layers, ports 7-14 (−3 dB PO)
8     2 layers, ports 9-10, nSCID = 0, −3 dB
      PO & RM
9     2 layers, ports 9-10, nSCID = 1, −3 dB
      PO & RM
10    2 layers, ports 11, 13, nSCID = 0, −3 dB
      PO & RM
11    2 layers, ports 11, 13, nSCID = 1, −3 dB
      PO & RM
12    2 layers, ports 12, 14, nSCID = 0, −3 dB
      PO & RM
13    2 layers, ports 12, 14, nSCID = 1, −3 dB
      PO & RM
14    2 layers, ports 7-8, nSCID = 0, −3 dB
      PO & RM
15    2 layers, ports 7-8, nSCID = 1, −3 dB
      PO & RM
16    2 layers, ports 11, 13, nSCID = 0 (0 dB
      PO)
17    2 layers, ports 11, 13, nSCID = 1 (0 dB
      PO)
18    Reserved
19    Reserved
20    Reserved
21    Reserved
22    Reserved
23    Reserved
24    Reserved
25    Reserved
26    Reserved
27    Reserved
28    Reserved
29    Reserved
30    Reserved
31    Reserved

In other examples, the power offset and rate matching information can also be jointly encoded with the antenna port(s), scrambling ID, and number of layers regardless of the number of codewords assigned (e.g., the bit field can be extended to 6 bits). Other alternatives, such as joint encoding of antenna port(s), number of layers and power offset (PO) and rate matching (RM) information instead, and a separate bit for scrambling ID may also be used.

In another example, joint coding of antenna port(s), scrambling identity, number of layers, power offset, and rate matching assumption may be indicated as illustrated in the exemplary coding format in Table 4 and Table 5 for one codeword assignment and two codewords assignment, respectively. In these examples, the one advantage is that only 5 bits may be needed to include the power offset and rate matching information.

One example of joint encoding of antenna port(s), scrambling identity, number of layers, PDSCH EPRE to DM-RS power ratio, and rate matching for one codeword transmissions is illustrated in Table 4 below.

TABLE 4

One Codeword:
Codeword 0 enabled,
Codeword 1 disabled
Value Message

0     1 layer, port 7, nSCID = 0 (0 dB
      PO)
1     1 layer, port 7, nSCID = 1 (0 dB
      PO)
2     1 layer, port 8, nSCID = 0 (0 dB
      PO)
3     1 layer, port 8, nSCID = 1 (0 dB
      PO)
4     2 layers, ports 7-8, nSCID = 0
      (0 dB PO)
5     3 layers, ports 7-9 (−3 dB PO)
6     4 layers, ports 7-10 (−3 dB PO)
7     1 layer, port 9, nSCID = 0, −3 dB
      PO & RM
8     1 layer, port 9, nSCID = 1, −3 dB
      PO & RM
9     1 layer, port 10, nSCID = 0, −3 dB
      PO & RM
10    1 layer, port 10, nSCID = 1, −3 dB
      PO & RM
11    1 layer, port 11, nSCID = 0, −3 dB
      PO & RM
12    1 layer, port 11, nSCID = 1, −3 dB
      PO & RM
13    1 layer, port 12, nSCID = 0, −3 dB
      PO & RM
14    1 layer, port 12, nSCID = 1, −3 dB
      PO & RM
15    1 layer, port 13, nSCID = 0, −3 dB
      PO & RM
16    1 layer, port 13, nSCID = 1, −3 dB PO
      & RM
17    1 layer, port 14, nSCID = 0, −3 dB PO
      & RM
18    1 layer, port 14, nSCID = 1, −3 dB PO
      & RM
19    2 layers, ports 7-8, nSCID = 1 (0 dB
      PO)
20    2 layers, ports 9-10, nSCID = 0, −3 dB
      PO & RM
21    2 layers, ports 9-10, nSCID = 1, −3 dB
      PO & RM
22    2 layers, ports 11, 13, nSCID = 0, −3 dB
      PO & RM
23    2 layers, ports 11, 13, nSCID = 1, −3 dB
      PO & RM
24    2 layers, ports 12, 14, nSCID = 0, −3 dB
      PO & RM
25    2 layers, ports 12, 14, nSCID = 1, −3 dB
      PO & RM
26    1 layer, port 7, nSCID = 0, −3 dB PO &
      RM
27    1 layer, port 7, nSCID = 1, −3 dB PO &
      RM
28    1 layer, port 8, nSCID = 0, −3 dB PO &
      RM
29    1 layer, port 8, nSCID = 1, −3 dB PO &
      RM
30    2 layers, ports 7-8, nSCID = 0, −3 dB
      PO & RM
31    2 layers, ports 7-8, nSCID = 1, −3 dB
      PO & RM

One example of joint encoding of antenna port(s), scrambling identity, number of layers, PDSCH EPRE to DM-RS power ratio and rate matching for two codeword transmissions is illustrated in Table 5 below.

TABLE 5

Two Codewords:
Codeword 0 enabled,
Codeword 1 enabled
Value Message

0     2 layers, ports 7-8, nSCID = 0 (0 dB PO)
1     2 layers, ports 7-8, nSCID = 1 (0 dB PO)
2     3 layers, ports 7-9 (−3 dB PO)
3     4 layers, ports 7-10 (−3 dB PO)
4     5 layers, ports 7-11 (−3 dB PO)
5     6 layers, ports 7-12 (−3 dB PO)
6     7 layers, ports 7-13 (−3 dB PO)
7     8 layers, ports 7-14 (−3 dB PO)
8     2 layers, ports 9-10, nSCID = 0, −3 dB PO
      & RM
9     2 layers, ports 9-10, nSCID = 1, −3 dB PO
      & RM
10    2 layers, ports 11, 13, nSCID = 0, −3 dB
      PO & RM
11    2 layers, ports 11, 13, nSCID = 1, −3 dB
      PO & RM
12    2 layers, ports 12, 14, nSCID = 0, −3 dB
      PO & RM
13    2 layers, ports 12, 14, nSCID = 1, −3 dB
      PO & RM
14    2 layers, ports 7-8, nSCID = 0, −3 dB PO
      & RM
15    2 layers, ports 7-8, nSCID = 1, −3 dB PO
      & RM
16    2 layers, ports 11, 13, nSCID = 0
      (0 dB PO)
17    2 layers, ports 11, 13, nSCID = 1
      (0 dB PO)
18    Reserved
19    Reserved
20    Reserved
21    Reserved
22    Reserved
23    Reserved
24    Reserved
25    Reserved
26    Reserved
27    Reserved
28    Reserved
29    Reserved
30    Reserved
31    Reserved

In another example, if two layer transmission is not supported by the DCI format, joint encoding of antenna port(s), scrambling identity, number of layers, PDSCH EPRE to DM-RS power ratio, and rate matching may still be accomplished as illustrated, for example, in Table 6. One example of joint encoding of antenna port(s), scrambling identity, number of layers, PDSCH EPRE to DM-RS power ratio, and rate matching for one codeword transmissions is illustrated in Table 6 below.

TABLE 6

One Codeword: Codeword 0
Value Message

0     1 layer, port 7, nSCID = 0 (0 dB
      PO)
1     1 layer, port 7, nSCID = 1 (0 dB
      PO)
2     1 layer, port 8, nSCID = 0 (0 dB
      PO)
3     1 layer, port 8, nSCID = 1 (0 dB
      PO)
4     1 layer, port 7, nSCID = 0, −3 dB
      PO & RM
5     1 layer, port 7, nSCID = 1, −3 dB
      PO & RM
6     1 layer, port 8, nSCID = 0, −3 dB
      PO & RM
7     1 layer, port 8, nSCID = 1, −3 dB
      PO & RM
8     1 layer, port 9, nSCID = 0, −3 dB
      PO & RM
9     1 layer, port 9, nSCID = 1, −3 dB
      PO & RM
10    1 layer, port 10, nSCID = 0, −3 dB
      PO & RM
11    1 layer, port 10, nSCID = 1, −3 dB
      PO & RM
12    1 layer, port 11, nSCID = 0 (0 dB
      PO)
13    1 layer, port 11, nSCID = 1 (0 dB
      PO)
14    1 layer, port 11, nSCID = 0, −3 dB PO
      & RM
15    1 layer, port 11, nSCID = 1, −3 dB PO
      & RM
16    1 layer, port 12, nSCID = 0, −3 dB PO
      & RM
17    1 layer, port 12, nSCID = 1, −3 dB PO
      & RM
18    1 layer, port 13, nSCID = 0 (0 dB PO)
19    1 layer, port 13, nSCID = 1 (0 dB PO)
20    1 layer, port 13, nSCID = 0, −3 dB PO
      & RM
21    1 layer, port 13, nSCID = 1, −3 dB PO
      & RM
22    1 layer, port 14, nSCID = 0, −3 dB PO
      & RM
23    1 layer, port 14, nSCID = 1, −3 dB PO
      & RM
24    Reserved
. . . . . .
. . . . . .
31    Reserved

Various embodiments of the present disclosure provide advanced MU interference suppression and/or cancellation support. For example, if advanced MU interference cancellation/suppression is supported by the UE, the network entity may indicate one or more of the following to the UE: the modulation and coding scheme (MCS) of interfering UEs (an interfering UE assigned with rank 2 may be identified as two virtual interfering UEs of rank 1), port(s) of interfering UEs, the number of interfering UEs, UE ID (e.g., C-RNTI) of interfering UEs, and/or the DM-RS port scrambling ID of the interfering UEs. In these interference reduction examples, signaling overhead may be reduced and/or managed by signaling the information of only the interfering UEs that are strong interferers or have an interference over a threshold. In other words, not all the information of all interfering UEs may be signaled to reduce signaling overhead. For example, interfering UEs that are assigned orthogonal DM-RS ports with respect to the desired UE may not be considered as UEs that are strong interferers.

FIG. 7 illustrates a block diagram of a UE 700 capable of performing advanced multi-user interference cancellation and/or suppression in accordance with illustrative embodiments of the present disclosure. For example, as illustrated, the de-multiplexer 705, channel estimator 710, and/or the MIMO (SU or MU) receiver 715 may utilize the information about the interfering UEs that was signaled in the control information received from the network entity as described above. To enable the advanced multi-user interference cancellation and/or suppression, the de-multiplexer 705 may receive signals from multiple ports. The channel estimator 710 may receive and estimate the channel using the RS of LTE 700 and the interfering UE(s). The MIMO receiver 715 receives the channel estimate from the channel estimator 710 and uses the estimate of the channel to reduce interference that may be present in the signals intended to be received by the UE. The demodulator 720 demodulates the received signals for decoding of the received signal by the decoder 725.

Additionally or alternatively, in various embodiments, the UE 700 may include a feedback loop 730 for canceling and/or subtracting interference of interfering UE(s) from the received signal. For example, given that the UE 700 information about the interfering UE(s), the UE 700 can decode and reconstruct the interfering signal(s), which can be fed back to the MIMO receiver 715 to subtract the interfering signal(s) for interference cancellation/suppression. Whether the UE 700 includes the feedback loop 730 canceling and/or subtracting interference of interfering UE(s) in addition to or instead of the interference suppression techniques described above is an implementation choice and embodiments of the present disclosure may include any combination of the cancellation and/or suppression techniques described herein.

The control signaling for interference reduction can be provided in a dynamic manner via DCI signaling. In one example embodiment, reduction in signaling overhead may be achieved by associating each DM-RS port with a port scrambling ID for PDSCH. In particular, PDSCH transmitted using a DM-RS port is scrambled with its port scrambling ID instead of the C-RNTI of the UE. For example, the initialization value of the scrambling sequence may be calculated as provided in equation 2 below:
c_init=n_Port-ID·2¹⁴+q·2¹³+└n_s/2┘·2⁹N_ID^cell  (Equation 2)
where n_Port-ID is the DM-RS port scrambling ID. Signaling of the interfering UE's DM-RS port scrambling ID has significantly lower overhead than signaling of C-RNTI. For example, if 8 ports are defined, only 3 bits are required for signaling of the DM-RS port scrambling ID, compared to 16 bits for C-RNTI signaling.

In another embodiment, only one codeword/transport block may be assigned to the desired UE. The bit field of the unused transport block in the DCI format (e.g. 2C/2D) may be used or reused to indicate the information of the interfering UE. In one example, assuming only transport block 1 is assigned to a UE, the MCS field of transport block 2 can be used to indicate the MCS of the interfering UE. The redundancy version and the NDI bits (3 bits total) for transport block 2 can also be used or reused to indicate the DM-RS port index of the interfering UE. One example of reinterpretation of fields in DCI format (e.g. 2C/2D) is illustrated in Table 7 below.

TABLE 7

Field in DCI format (e.g. 2C/2D) Interpretation

MCS of TB 2                      MCS of interfering UE
RV and NDI of TB2                Port index of interfering UE

FIG. 8 illustrates an indication of resource assignments for a UE having an overlapping allocation of resource blocks in accordance with various embodiments of the present disclosure. To effectively enable interference cancellation as described above, UEs may be scheduled with an overlapping allocation of RBs in frequency. While this scheduling scheme may somewhat limit scheduling flexibility, this scheduling scheme may reduce the signaling overhead for interference reduction. For example, the network entity may define a group of RBs over which the same set of UEs is allocated the same set of DMRS ports. Since the amount of coded data sent to each UE may be different, a UE may have to further detect the presence or absence of a UE allocation in the RBs on the assigned port.

In one example, the network entity may signal information related to the resource allocation information of a co-scheduled UE. In DCI Format 2C, the 3GPP Specification 36.212 describes the signaling of resource allocation to a UE. A resource allocation header (resource allocation type 0/type 1)—1 bit as defined in section 7.1.6 (of 36.213). If downlink bandwidth is less than or equal to 10 PRBs, there is no resource allocation header, and resource allocation type 0 is assumed. Resource block assignment: for resource allocation type 0 as defined in section 7.1.6.1 of [36.213] and ┌N_RB^DL/P┐ bits provide the resource allocation; for resource allocation type 1 as defined in section 7.1.6.2 (of 36.213) ┌ log₂(P)┐ bits of this field are used as a header specific to this resource allocation type to indicate the selected resource blocks subset, 1 bit indicates a shift of the resource allocation span, and (┌N_RB^DL/P┐−┌ log₂(P)┐−1) bits provide the resource allocation, where the value of P depends on the number of DL resource blocks as indicated in section 7.1.6.1 (of 36.213).

The resource allocation defined includes a bitmap or a selection from a set of localized or distributed resource blocks and virtual resource blocks or resource block groups. This resource allocation allows sufficient flexibility to share the resources in frequency to different UEs. Further, a resource allocation header indicates a selection between the resource allocation types.

To enable support for interference cancellation, some further coordination of resource allocation may be useful. In various embodiments, a co-channel resource allocation block assignment field and co-channel resource allocation header may be defined to indicate the resource allocation information of a co-scheduled UE. In these embodiments, the UE may assume the interference from that UE only in the set of overlapping resources. For example, as illustrated in FIG. 8, the UE assumes interference from only the co-scheduled/overlapping blocks and no interference is assumed in the non-overlapping blocks.

In another example, the set of overlapping resources over which an interfering UE is scheduled may be directly indicated with a resource allocation header and a resource block assignment field. In another example, the set of overlapping resources over which an interfering UE is not scheduled may be directly indicated with a resource allocation header and a resource block assignment field. In another example, a set of resource assignments may be pre-defined (e.g., by higher layer signaling or fixed) and dynamic signaling may be used to select between the different resource assignments to reduce overhead in DCI. In another example, co-channel resource allocation may be implicitly determined by the UE using one or more of the other parameters signaled for the other UE, (e.g., port index, port RNTI, a pre-configured group ID for similarly scheduled UEs). In these examples, the indicated resource allocation corresponds to the resources over which the UE can expect interference and the associated signaled interference reduction parameters (e.g., MCS, port RNTI, port ID, etc.) are applicable.

In various embodiments, the base station may transmit the PDSCH using DM-RS ports that are scrambled with the port's scrambling ID instead of the C-RNTI of the UE, and the network entity assigns each DM-RS port a different port scrambling ID. In one example, the scrambling initialization equation may be calculated according to equation 3 below:
c_init=n_Port-ID·2¹⁴+q·2¹³+└n_s/2┘·2⁹+N_ID^cell  (Equation 3)
where n_Port-ID is the DM-RS port scrambling ID. The UE can be configured or controlled by the network entity to perform PDSCH descrambling using the legacy method or the descrambling method described above. This configuration/control can be semi-static (i.e. signaled by a higher layer), for example, via transmission mode configuration. Table 8 provides one example of an illustration of a higher layer configuration of the PDSCH scrambling method.

TABLE 8

Higher layer signaling PDSCH scrambling method

0                      Legacy scrambling method
1                      Scrambled with the port scrambling ID

In other embodiments, the configuration or control can also be dynamic. For example, the UE may switch between the legacy method and the method of descrambling using the port scrambling ID, depending on the control information received from PDCCH or ePDCCH. In One example, the dynamic control may be indicated using 1-bit signaling in the DCI format (for DL assignment). For example, a “0” indicates the legacy method should be used to receive the corresponding PDSCH, and a “1” indicates that method of descrambling using the port scrambling ID should be used to receive the corresponding PDSCH. In another example, the DM-RS ports assigned or the rank assigned. For example, if the DM-RS port(s) assigned are 7, 7 and 8, 9, 9 and 10, or, more generally, if the rank assigned is less than or equal to some specified number x where x can e.g. be 2, the port scrambling ID method is used (i.e., MU-MIMO operation may be assumed). Otherwise, the UE assumes that the legacy method is used (i.e., SU-MIMO operation may be assumed).

In another example, the type of DCI format may be used to indicate the PDSCH scrambling method. For example, if DCI format 1A is received, the legacy method is assumed to be used to descramble the corresponding PDSCH, else if DCI format 2C (or reference DCI format) is received, the port scrambling ID method is used to descramble the corresponding PDSCH. In another example, further dependency on where the DCI format was received may be used to indicate the PDSCH scrambling method. For example, if the DCI format 1A was received in the common search space of the PDCCH/ePDCCH region, then the legacy method is used to descramble the corresponding PDSCH, else if the DCI format 1A was received in the UE-specific search space of the PDCCH/ePDCCH region, then the port scrambling ID method is used to descramble the corresponding PDSCH. The dynamic control methods above assume the UE is already configured beforehand (higher-layer e.g. RRC) to apply the dynamic control methods.

One benefit of scrambling PDSCH with port scrambling ID instead of the C-RNTI may include facilitation of MU-interference cancellation and/or suppression for PDSCH. For example, given that the UE knows the port scrambling ID of the UE, as well as the port scrambling ID of the interfering UE, the port scrambling ID method allows the UE to descramble and then decode the interfering PDSCH, which can then be used for interference cancellation/suppression as discussed above, for example, with regard to the feedback loop 730 in FIG. 7.

In various embodiments, the signaling of the port scrambling ID signaling may include a predefined port scrambling ID for each DM-RS port. Table 9 illustrates one example of a mapping for 8 ports. However, mapping for fewer numbers of DM-RS ports is also possible (e.g. just ports 7, 8, 9, and 10).

TABLE 9

DM-RS port index Port scrambling ID


7                000
8                001
9                010
10               011
11               100
12               101
13               110
14               111

In this example, if the UE is signaled or detects blindly the interfering UE's port(s), the UE is able to derive the port scrambling ID used for the PDSCH of the interfering UE.

In another example, a higher layer configuration of port scrambling ID for each DM-RS port (e.g. via an RRC) may be used to indicated the port scrambling ID to the UE. Table 10 illustrates one example of a mapping for 8 ports. However, mapping for fewer numbers of DM-RS ports is also possible (e.g. just ports 7, 8, 9, and 10). For example, the number of bits for the ID value can be log, (number of DM-RS ports) (i.e., 3 for 8 ports and 2 for 4 ports) or the number of bits may be of the same length as the C-RNTI (i.e., 16 bits).

TABLE 10

DM-RS port index Port scrambling ID


7                A
8                B
9                C
10               D
11               E
12               F
13               G
14               H

In this example, if the UE is signaled or detects blindly the interfering UE's port(s), the UE is able to derive the port scrambling ID used for the PDSCH of the interfering UE. In some embodiments, the higher layering signaling of Table 10 is common for all MU UEs may be broadcasted. In other embodiments (e.g., if the configuration and the configured value are UE-specific), the UE should also be signaled the port-scrambling ID of the interfering UE or the UE should blindly detect the port scrambling ID of the interfering UE. Signaling of the DM-RS port scrambling ID of the interfering UE has significantly lower overhead than signaling of C-RNTI. For example, if 8 ports are defined, only 3 bits are required for signaling of the DM-RS port scrambling ID, compared to 16 bits for C-RNTI signaling.

FIG. 9 illustrates a process for identifying resource scheduling for a UE in a multiple-user multiple-input multiple-output wireless communication system in accordance with various embodiments of the present disclosure. For example, the process depicted in FIG. 9 may be performed by the receiver 310 in FIG. 3. The process may also be implemented by the UE 700 in FIG. 7.

The process begins by the UE receiving downlink control information (step 905). For example, in step 905, the UE may receive downlink control information in control signaling in a DCI format. The downlink control information may be statically or semi-statically signaled. Alternatively, the downlink control information may be dynamically signaled, for example, in each downlink subframe. The UE then identifies DM-RS port(s) assigned to the UE (step 910). For example, in step 910, the UE may identify the DM-RS port(s) for the UE in the downlink control information.

The UE then identifies a PDSCH EPRE to DM-RS EPRE ratio (step 915). For example, in step 915, the UE may identify the PDSCH EPRE to DM-RS EPRE ratio and whether rate matching is used from a jointly encoded signal bit field in the downlink control information. For example, the UE may identify the PDSCH EPRE to DM-RS EPRE ratio as 0 dB or −3 dB. The UE may also identify a number layers, a scrambling identifier, and whether rate matching is used from a jointly encoded message in the downlink control information. The UE may also identify information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more port(s) assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs. The UE may also identify a DM-RS port scrambling identifier for a DM-RS port assigned to an interfering UE to use to calculate an initialization value for a scrambling sequence for resources assigned to the interfering UE and reduce interference. The UE may also identify whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE to reduce interference.

The UE then receives a downlink subframe (step 920). The UE then identifies resource block(s) including data intended for the UE (step 925). The UE then identifies the data intended for the UE in the resource block (step 930). For example, in step 930, the UE may identify the data using the one or more DM-RS port(s) and the PDSCH EPRE to DM-RS EPRE ratio. The resource block in the downlink subframe may include data for multiple users in the wireless communication system. Thereafter, the UE returns to step 920 to receive and decode data from additional downlink subframes.

FIG. 10 illustrates a process for scheduling resources in a multiple-user multiple-input multiple-output wireless communication system in accordance with various embodiments of the present disclosure. For example, the process depicted in FIG. 10 may be performed by the transmitter 305 in FIG. 3. The process may also be implemented by a network entity, such as an eNB, RRH, relay station, underlay base station, GW, or BSC.

The process begins by the network entity identifying DM-RS port(s) to assign to the UE (step 1005). The network entity then identifies a PDSCH EPRE to DM-RS EPRE ratio (step 1010). For example, in step 1010, the network entity may use the PDSCH EPRE to DM-RS EPRE ratio to multiplex data in a same frequency resource.

The network entity then sends downlink control information (step 1015). For example, in step 1015, the network entity may send the control information to the UE to indicate the DM-RS port(s) and PDSCH EPRE to DM-RS EPRE ratio. The downlink control information may be statically or semi-statically signaled. Alternatively, the downlink control information may be dynamically signaled, for example, in each downlink subframe. In one example, the PDSCH EPRE to DM-RS EPRE ratio and whether rate matching is used may be jointly encoded into a signal bit field in the downlink control information. The one or more DM-RS port(s) assigned to the UE, a number layers, a scrambling identifier, the PDSCH EPRE to DM-RS EPRE ratio, and whether rate matching is used may be jointly encoded in the downlink control information. The downlink control information may include an indication of information about one or more interfering UEs including at least one of a modulation and coding scheme of the one or more interfering UEs, one or more port(s) assigned to the one or more interfering UEs, a number of the one or more interfering UEs, a UE identifier for the one or more interfering UEs, or a DM-RS port scrambling identifier for the one or more interfering UEs. The downlink control information may include an indication of a DM-RS port scrambling identifier for a DM-RS port assigned to an interfering UE. The downlink control information may include an indication of an initialization value for a scrambling sequence for resources assigned to the interfering UE using the DM-RS port scrambling identifier. The downlink control information may include an indication of whether an interfering UE is allocated a group of resource blocks that overlaps with resource blocks assigned to the UE.

The network entity then transmits downlink subframes in accordance with the scheduled resources (step 1020). For example, in step 1020, the network entity may transmit the downlink subframes according to the one or more DM-RS port(s) assigned to the UE and the PDSCH EPRE to DM-RS EPRE ratio.

Although FIGS. 9 and 10 illustrate examples of processes for scheduling resources and identifying resource scheduling in a MU-MIMO wireless communication system, respectively, various changes could be made to FIGS. 9 and 10. For example, while shown as a series of steps, various steps in each figure could overlap, occur in parallel, occur in a different order, or occur multiple times.

Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.

Claims

1. A method for identifying resource scheduling for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:

receiving downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the ue, a number of layers, a scrambling identifier (SCID), and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio;

identifying, from the downlink control information, the one or more demodulation reference signal (DM-RS) ports assigned to the ue and a physical downlink shared channel ( the pdsch) energy per resource element ( epre) to DM-RS epre ratio according to the number of layers; and

identifying distinguishing a signal including data intended for the ue in a resource block in a downlink subframe from another signal for an interfering ue in the resource block including data intended for another the interfering ue using the SCID for the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio, wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system, and

identifying, from the downlink control information, a DM-RS port SCID for a DM-RS port assigned to the interfering ue;

identifying an initialization value for a scrambling sequence for resources assigned to the interfering ue using the DM-RS port SCID; and

reducing interference from the interfering ue in identifying the data intended for the ue in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering ue.

2. The method of claim 1, wherein the ue is assigned ports from one DM-RS code division multiplexing (cdm) group, the method further comprising:

identifying the pdsch epre to DM-RS epre ratio and whether rate matching around another DM-RS cdm group is used from a jointly encoded signal bit field in the downlink control information.

3. The method of claim 1, wherein identifying the one or more DM-RS ports assigned to the ue and the pdsch epre to DM-RS epre ratio comprises identifying the one or more DM-RS ports assigned to the ue, a number layers, a scrambling identifier, the pdsch epre to DM-RS epre ratio, and whether rate matching is used from a jointly encoded message in the downlink control information is 0 decibels (dB) or −3 dB.

4. The method of claim 1, further comprising:

identifying, from the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues; and

reducing interference from at least one of the one or more interfering ues in identifying the data intended for the ue in the resource block using the information about one or more interfering ues.

5. The method of claim 1 further comprising:

identifying, from the downlink control information, a DM-RS port scrambling identifier fora DM-RS port assigned to an interfering ue;

identify an initialization value for a scrambling sequence for resources assigned to the interfering ue using the DM-RS port scrambling identifier; and

reducing interference from the interfering ue in identifying the data intended for the ue in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering ue.

6. The method of claim 1, further comprising:

identifying, from the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the ue; and

reducing interference from the interfering ue in the group of resource blocks that overlaps with resource blocks assigned to the ue in identifying the data intended for the ue.

7. A method for scheduling resources in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:

identifying one or more demodulation reference signal (DM-RS) ports to assign to a ue and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio for identifying a signal including data intended for the ue in a resource block in a downlink subframe from another signal in the resource block including data intended for another ue; and

including an indication of the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio in downlink control information,

wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.

8. The method of claim 7, wherein including the indication of the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio in the downlink control information comprises jointly encoding an indication of the one or more DM-RS ports assigned to the ue, a number layers, a scrambling identifier, the pdsch epre to DM-RS epre ratio, and whether rate matching is used from in the downlink control information.

9. The method of claim 7 further comprising including, in the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues for reducing interference from at least one of the one or more interfering ues.

10. The method of claim 7 further comprising including, in the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the n for reducing interference from the interfering ue in the group of resource blocks that overlaps with resource blocks assigned to the ue.

11. An apparatus configured to identify resource scheduling for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:

a receiver configured to receive downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the ue, a number of layers, and a scrambling identifier (SCID), and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio; and

a controller configured to:

identify, from the downlink control information, the one or more demodulation reference signal (DM-RS) ports assigned to the ue, the number of layers, the SCID, and a physical downlink shared channel ( the pdsch) energy per resource element ( epre) to DM-RS epre ratio according to the number of layers, and

identify distinguish a signal including data intended for the ue in a resource block in a downlink subframe from another signal in the resource block including data intended for another ue using the SCID for the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio,

wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system,

wherein the controller is configured to identify, from the downlink control information, an SCID for a DM-RS port assigned to an interfering ue, and identify an initialization value for a scrambling sequence for resources assigned to the interfering ue using the DM-RS port SCID, the apparatus further comprising:

control receiver processing circuitry configured to reduce interference from the interfering ue in identifying the data intended for the ue in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering ue.

12. The apparatus of claim 11, wherein the ue is assigned ports from one DM-RS code division multiplexing (cdm) group, and wherein the controller is configured to identify the pdsch epre to DM-RS epre ratio and whether rate matching around another DM-RS cdm group is used from a jointly encoded signal bit field in the downlink control information.

13. The apparatus of claim 11, wherein in identifying the one or more DM-RS ports assigned to the ue and the pdsch epre to DM-RS epre ratio, the controller is configured to identify the one or more DM-RS ports assigned to the ue, a number layers, a scrambling identifier, the pdsch epre to DM-RS epre ratio, and whether rate matching is used from a jointly encoded message in the downlink control information is 0 decibels (dB) or −3 dB.

14. The apparatus of claim 11, wherein the controller is configured to: identify, from the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues; and, the apparatus further comprising:

control receiver processing circuitry configured to reduce interference from at least one of the one or more interfering ues in identifying the data intended for the ue in the resource block using the information about one or more interfering ues.

15. The apparatus of claim 11, wherein the controller is configured to:

identify, from the downlink control information, a DM-RS port scrambling identifier for a DM-RS port assigned to an interfering ue;

identify an initialization value for a scrambling sequence for resources assigned to the interfering ue using the DM-RS port scrambling identifier; and

control receiver processing circuitry to reduce interference from the interfering ue in identifying the data intended for the ue in the resource block using the initialization value for the scrambling sequence for resources assigned to the interfering ue.

16. The apparatus of claim 11, wherein the controller is configured to: identify, from the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the ue; and, the apparatus further comprising:

control receiver processing circuitry configured to reduce interference from the interfering ue in the group of resource blocks that overlaps with resource blocks assigned to the ue in identifying the data intended for the ue.

17. An apparatus configured to schedule resources in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:

a transmitter; and

a controller configured to:

identify one or more demodulation reference signal (DM-RS) ports to assign to a ue and a physical down- link shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio for identifying a signal including data intended for the ue in a resource block in a downlink subframe from another signal in the resource block including data intended for another ue, and

control the transmitter to include an indication of the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio in downlink control information,

wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.

18. The apparatus of claim 17, wherein in controlling the transmitter to include the indication of the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio in the downlink control information, the controller is configured to control the transmitter to jointly encode an indication of the one or more DM-RS ports assigned to the ue, a number layers, a scrambling identifier, the pdsch epre to DM-RS epre ratio, and whether rate matching is used from in the downlink control information.

19. The apparatus of claim 17, wherein the controller is configured to control the transmitter to include, in the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues for reducing interference from at least one of the one or more interfering ues.

20. The apparatus of claim 17, wherein the controller is configured to control the transmitter to include, in the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the ue for reducing interference from the interfering ue in the group of resource blocks that overlaps with resource blocks assigned to the ue.

21. A method for identifyinq resource scheduling for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:

receiving downlink control information;

receiving data in a resource block in a downlink subframe according to a bit field in the downlink control information, wherein the downlink control information indicates one or more demodulation reference signal (DM-RS) ports assigned to the ue, a number of layers, a scrambling identifier, a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio, and whether rate matching around at least one port unassigned to the ue and in a DM-RS code division multiplexing (cdm) group is used, wherein:

for a first value of the bit field, (i) one or more first DM-RS ports included in a first DM-RS cdm group are assigned to the ue, (ii) a pdsch epre to dmrs epre ratio has a value of 0 dB, and (iii) the data siqnal is mapped to the resource for a second DM-RS cdm qroup unassiqned to the ue,

for a second value of the bit field, (i) one or more second DM-RS ports included in the first DM-RS cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has a value of −3 dB, and (iii) the data siqnal is not mapped to the resource for the second DM-RS cdm group unassigned to the ue,

for a third value of the bit field, (i) one or more third DM-RS ports included in the second DM-RS cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has the value of −3 dB, and (iii) the data siqnal is not mapped to the resource for the first DM-RS cdm group unassigned to the ue, and

for a fourth value of the bit field, (i) both one or more fourth DM-RS ports included in the first DM-RS cdm group and one or more fifth DM-RS ports included in the second DM-RS cdm group are assigned to the ue, and (ii) the pdsch epre to DM-RS epre ratio has the value of −3 dB; and

identifying data intended for the ue in the resource block in the downlink subframe using the one or more DM-RS ports assigned to the ue and the pdsch epre to DM-RS epre ratio,

wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.

22. The method of claim 21, wherein the pdsch epre to dmrs epre ratio is 0 decibels (dB) to −3 dB.

23. The method of claim 21, further comprising:

identifying, from the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues.

24. The method of claim 21, further comprising:

identifying, from the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the ue.

25. A method for identifying resource scheduling for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:

receiving downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the ue, a number of layers, a scrambling identifier (SCID), and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio;

identifying, from the downlink control information, the one or more DM-RS ports assigned to one or more ue(s) and the pdsch epre to DM-RS epre ratio according to the number of layers;

receiving a signal including one or more layers in at least one resource block, wherein the signal comprises a ue-specific signal identifiable from signals for one or more other ues based on SCID(s) for the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio, wherein a layer is associated with a DM-RS port;

identifying, from the downlink control information, a DM-RS port SCID for a DM-RS port assigned to one of one or more other ues;

identify an initialization value for a scrambling sequence for resources assigned to the one of the one or more other ues using the DM-RS port SCID; and

reducing interference from the one of the one or more other ues in identifying data intended for the ue in the resource block using the initialization value for the scrambling sequence for resources assigned to the one of the one or more other ues.

26. The method of claim 25, further comprising:

identify an initialization value for a scrambling identifier for resources assigned to one of the one more interfering ues using the scrambling identifier.

27. A method for scheduling resources for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:

identifying one or more demodulation reference signal (DM-RS) ports to assign to the ue and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio for identifying data intended for the ue in a resource block in a downlink subframe;

including an information indicating the one or more DM-RS ports assigned to the ue, a number of layers, a scrambling identifier, the pdsch epre to DM-RS epre ratio, and whether rate matching around one or more ports from a DM-RS code division multiplexing (cdm) group unassigned to the ue is used in downlink control information;

transmitting the downlink control information; and

transmitting the data intended for the ue in the resource block in the downlink subframe according to a bit field in the downlink control information, wherein:

for a first value of the bit field, (i) one or more first dmrs ports included in a first dmrs cdm group are assigned to the ue, (ii) a pdsch epre to dmrs epre ratio has a value of 0 dB, and (iii) the data signal is mapped to the resource for a second dmrs cdm group unassigned to the ue,

for a second value of the bit field, (i) one or more second dmrs ports included in the first dmrs cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has a value of −3 dB, and (iii) the data signal is not mapped to the resource for the second dmrs cdm group unassigned to the ue,

for a third value of the bit field, (i) one or more third dmrs ports included in the second dmrs cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has the value of −3 dB, and (iii) the data signal is not mapped to the resource for the first dmrs cdm group unassigned to the ue, and

for a fourth value of the bit field, (i) both one or more fourth dmrs ports included in the first dmrs cdm group and one or more fifth dmrs ports included in the second dmrs cdm group are assigned to the ue, and (ii) the pdsch epre to dmrs epre ratio has the value of −3 dB,

wherein the resource block in the downlink subframe includes the data for multiple users in the wireless communication system.

28. The method of claim 27, further comprising including, in the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues.

29. A method for scheduling resources for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the method comprising:

identifying one or more demodulation reference signal (DM-RS) ports to assign to the ue and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio for identifying data intended for the ue in a resource block in a downlink subframe;

including an information related to the one or more DM-RS ports assigned to the ue, a number of layers, a scrambling identifier, the pdsch epre to DM-RS epre ratio, and whether rate matching around one or more ports from a DM-RS code division multiplexing (cdm) group unassigned to the ue is used in downlink control information;

including, in the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the ue;

transmitting the downlink control information; and

transmitting the data intended for the ue in the resource block in the downlink subframe based on a case determined among four cases according to a bit field in the downlink control information, wherein the four cases include:

a first case that (i) one or more first dmrs ports included in a first dmrs cdm group are assigned to the ue, (ii) a pdsch epre to dmrs epre ratio has a value of 0 dB, (iii) the data signal is mapped to the resource for a second dmrs cdm group unassigned to the ue,

a second case that (i) one or more second dmrs ports included in the first dmrs cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has a value of −3 dB, and (iii) the data signal is not mapped to the resource for the second dmrs cdm group unassigned to the ue,

a third case that (i) one or more third dmrs ports included in the second dmrs cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has the value of −3 dB, and (iii) the data signal is not mapped to the resource for the first dmrs cdm group unassigned to the ue, and

a fourth case that (i) both one or more fourth dmrs ports included in the first dmrs cdm group and one or more fifth dmrs ports included in the second dmrs cdm group are assigned to the ue, and (ii) the pdsch epre to dmrs epre ratio has the value of −3 dB,

wherein the resource block in the downlink subframe includes the data for multiple users in the wireless communication system.

30. An apparatus configured to identify resource scheduling for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:

a receiver configured to

receive downlink control information including a bit field related to an antenna port; and

receive data in a resource block in a downlink subframe according to a bit field in the downlink control information, wherein the downlink control information indicates one or more demodulation reference signal (DM-RS) ports assigned to the ue, a number of layers, a scrambling identifier, a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio, and whether rate matching around at least one port unassigned to the ue and in a DM-RS code division multiplexing (cdm) group is used, wherein:

for a first value of the bit field, (i) one or more first DM-RS ports included in a first DM-RS cdm group are assigned to the ue, (ii) a pdsch epre to dmrs epre ratio has a value of 0 dB, and (iii) the data signal is mapped to the resource for a second DM-RS cdm group unassigned to the ue,

for a second value of the bit field, (i) one or more second DM-RS ports included in the first DM-RS cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has a value of −3 dB, and (iii) the data signal is not mapped to the resource for the second DM-RS cdm group unassigned to the ue,

for a third value of the bit field, (i) one or more third DM-RS ports included in the second DM-RS cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has the value of −3 dB, and (iii) the data signal is not mapped to the resource for the first DM-RS cdm group unassigned to the ue, and

for a fourth value of the bit field, (i) both one or more fourth DM-RS ports included in the first DM-RS cdm group and one or more fifth DM-RS ports included in the second DM-RS cdm group are assigned to the ue, and (ii) the pdsch epre to DM-RS epre ratio has the value of −3 dB; and

a controller configured to identify data intended for the ue in a resource block in a downlink subframe using the one or more DM-RS ports assigned to the ue and the pdsch epre to DM-RS epre ratio,

wherein the resource block in the downlink subframe includes data for multiple users in the wireless communication system.

31. The apparatus of claim 30, wherein the pdsch epre to dmrs epre ratio is 0 decibels (dB) to −3 dB.

32. The apparatus of claim 30, wherein the controller is configured to identify, from the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the ue.

33. The apparatus of claim 30, wherein the controller is configured to identify, from the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues.

34. An apparatus configured to identify resource scheduling for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:

a receiver configured to receive downlink control information indicating one or more demodulation reference signal (DM-RS) ports assigned to the ue, a number of layers, a scrambling identifier (SCID), and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio; and

a controller configured to:

identify, from the downlink control information, the one or more DM-RS ports assigned to one or more ue(s) and the pdsch epre to DM-RS epre ratio according to the number of layers, and

receive, via the receiver, a signal including one or more layers in at least one resource block, wherein the signal comprises a ue-specific signal identifiable based on SCID(s) for the one or more DM-RS ports and the pdsch epre to DM-RS epre ratio, wherein a layer is associated with a DM-RS port,

identify, from the downlink control information, a DM-RS port scrambling identifier for a DM-RS port assigned to one of one or more other ues,

identify an initialization value for a scrambling sequence for resources assigned to the one of the one or more other ues using the DM-RS port scrambling identifier, and

control the receiver to reduce interference from the one of the one or more other ues in identifying data intended for the ue in the resource block using the initialization value for the scrambling sequence for resources assigned to the one of the one or more other ues.

35. The apparatus of claim 34, wherein the controller is configured to identify an initialization value for a scrambling identifier for resources assigned to one of the one more interfering ues using the scrambling identifier.

36. An apparatus configured to schedule resources for a user equipment (ue) in a multiple-user multiple-input multiple-output wireless communication system, the apparatus comprising:

a controller configured to:

identify one or more demodulation reference signal (DM-RS) ports to assign to a ue and a physical downlink shared channel (pdsch) energy per resource element (epre) to DM-RS epre ratio for identifying data intended for the ue in a resource block in a downlink subframe, and

include an information related to the one or more DM-RS ports assigned to the ue, a number of layers, a scrambling identifier, the pdsch epre to DM-RS epre ratio, and whether rate matching around one or more ports from a DM-RS code division multiplexing (cdm) group unassigned to the ue is used in downlink control information; and a transmitter coupled with the controller, wherein the transmitter is configured to transmit the downlink control information, and

a transmitter coupled with the controller, wherein the transmitter is condigured to

transmit the downlink control information, and

transmit the data intended for the ue in the resource block in the downlink subframe based on a case determined among four cases according to a bit field in the downlink control information, wherein the four cases include:

a first case that (i) one or more first dmrs ports included in a first dmrs cdm group are assigned to the ue, (ii) a pdsch epre to dmrs epre ratio has a value of 0 dB, (iii) the data signal is mapped to the resource for a second dmrs cdm group unassigned to the ue,

a second case that (i) one or more second dmrs ports included in the first dmrs cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has a value of −3 dB and (iii) the data signal is not mapped to the resource for the second dmrs cdm group unassigned to the ue,

a third case that (i) one or more third dmrs ports included in the second dmrs cdm group are assigned to the ue, (ii) the pdsch epre to DM-RS epre ratio has the value of −3 dB and (iii) the data signal is not mapped to the resource for the first dmrs cdm group unassigned to the ue, and

a fourth case that (i) both one or more fourth dmrs ports included in the first dmrs cdm group and one or more fifth dmrs ports included in the second dmrs cdm group are assigned to the ue, and (ii) the pdsch epre to dmrs epre ratio has the value of −3 dB,

wherein the resource block in the downlink subframe includes the data for multiple users in the wireless communication system.

37. The apparatus of claim 36, wherein the controller is configured to include, in the downlink control information, information about one or more interfering ues including at least one of a modulation and coding scheme of the one or more interfering ues, one or more ports assigned to the one or more interfering ues, a number of the one or more interfering ues, a ue identifier for the one or more interfering ues, or a DM-RS port scrambling identifier for the one or more interfering ues.

38. The apparatus of claim 37, wherein the controller is configured to include, in the downlink control information, whether an interfering ue is allocated a group of resource blocks that overlaps with resource blocks assigned to the ue.