Demodulation reference signal configuration and indication schemes
A method of wireless communication is described. The wireless communication method includes receiving, by a communication device, an antenna port indication; and determining, by the communication device, a first demodulation reference signal (DMRS) port based on the antenna port indication. The first DMRS port is mapped to two resource elements of one physical resource block on one OFDM (Orthogonal Frequency Division Multiplexing) symbol.
1 . A method of wireless communication, comprising:
receiving, by a communication device, an antenna port indication indicating one from multiple demodulation reference signal (DMRS) port indications that include i) a first DMRS port indication corresponding to a first type of a user device configured to operate according to a first antenna port configuration, and ii) a second DMRS port indication corresponding to a second type of a user device configured to operate according to a second antenna port configuration, the communication device being either the first type of the user device or the second type of the user device; and
determining, by the communication device, a first demodulation reference signal (DMRS) port or a second DMRS port based on the antenna port indication, and
wherein the first DMRS port is mapped to two resource elements of one physical resource block on one OFDM (Orthogonal Frequency Division Multiplexing) symbol, and
wherein the second DMRS port is mapped to at least four resource elements of the physical resource block on the OFDM symbol.
2 . The method of claim 1 , wherein the two resource elements are at least one of: 1) continuous in frequency domain for DMRS type 2, or 2) comb in frequency domain for DMRS type 1.
3 . The method of claim 1 , wherein the antenna port indication includes at least one of an antenna port index, a number of Code Division Multiplexing (CDM) group without data, or an index of CDM group without data,
wherein the antenna port indication indicates whether a DMRS port is mapped on the two resource elements or more than two resource elements on the physical resource block on the OFDM (Orthogonal Frequency Division Multiplexing) symbol, and
wherein the antenna port index has a value in a range specific for the communication device configured according to an antenna port configuration, the range being different from that for another communication device configured according to a legacy configuration.
4 . The method of claim 1 , where the antenna port indication is indicated using a radio resource control (RRC) signaling or a MAC control element, or a downlink control information.
5 . The method of claim 1 , wherein the first DMRS port is determined by the first type of the user device and the first DMRS port is scheduled with at least one of:
1) an additional first DMRS port;
2) a second DMRS port mapped on at least four resource elements on the physical resource block of the OFDM symbol, wherein the at least four resource elements are overlapping with the two resource elements to which the first DMRS port maps, wherein a CDM group of the second DMRS port is scheduled on resource elements overlapping with at least one of: 1) three CDM groups of the first DMRS port for DMRS type 1, or 2) two CDM groups of the first DMRS port for DMRS type 2; or
3) a second DMRS port mapped on 4 resource elements non-overlapping with the two resource elements of the first DMRS port.
6 . The method of claim 1 , wherein the first DMRS port has a sequence associated with at least one of a max number of CDM groups based on whether the first DMRS port corresponds to DMRS type 1 or DMRS type 2, or an index of a resource element.
7 . The method of claim 6 , wherein the sequence is determined based on at least one of equations:
k
=
{
12
*
n
+
2
*
k
′
+
Δ
,
configuration
DMRS
type
I
12
*
n
+
k
′
+
Δ
,
configuration
DMRS
type
II
k
′
=
0.1
;
n
=
0
,
1
…
;
(
1
)
c
init
=
(
2
17
(
N
symb
slot
n
s
,
f
μ
+
l
+
1
)
(
2
N
ID
n
_
SCID
λ
_
+
1
)
+
2
17
⌊
λ
_
2
⌋
+
2
N
ID
n
_
SCID
λ
_
+
n
_
SCID
λ
_
)
mod
2
31
λ
_
=
{
λ
mod
2
,
configure
typeI
λ
mod
3
,
configure
typeII
;
or
(
2
)
r
(
a
*
n
+
k
′
+
b
)
k
′
=
0
,
1
;
n
=
0
,
1
…
a
=
{
6
,
configuration
type
I
4
,
configuration
type
II
b
=
{
2
*
⌊
Δ
4
⌋
,
configuration
type
I
2
*
⌊
Δ
6
⌋
,
configuration
type
II
(
3
)
wherein r is a sequence of the first DMRS port, c init is an initial equation for calculation of r, k is an index of resource elements, a and b are associated with a max number of CDM groups based on a type of an antenna port, and λ and Δ are associated to an index of a CDM group of the first DMRS port.
8 . The method of claim 1 , wherein a number of a CDM group without data is between 1 to 6.
9 . The method of claim 1 , further comprising:
calculating energy per resource element (EPRE) at least one of DMRS, a physical downlink shared channel (PDSCH), or a physical uplink shared channel (PUSCH) based on a number of CDM groups without data, and wherein the EPRE is calculated for the first DMRS port by multiplying two times of a number of CDM groups without data of a second DMRS port mapped to more than two resource elements of the physical resource block on the OFDM symbol.
10 . The method of claim 1 , further comprising:
receiving or transmitting one or more demodulation reference signals based on a determined antenna port configuration.
11 . A method of wireless communication, comprising:
scheduling user devices to utilize a same time-frequency resource, each user device corresponding to a first type of a user device configured to operate according to a first antenna port configuration or a second type of a user device configured to operate according to a second antenna port configuration;
transmitting, to the first type of the user device, a first antenna port indication having an antenna index whose value is in a first range not overlapping with a second range; and
transmitting, to the second type of the user device, a second antenna port indication having an antenna index whose value is in the second range, and
wherein the first antenna port configuration maps an antenna port for one or more demodulation reference signals (DMRSs) to two resource elements of a physical resource block on a symbol and the second antenna port configuration maps the antenna port to at least 4 resource elements of the physical resource block on the symbol.
12 . The method of claim 11 ,
wherein the first type of the user device and the second type of the user device have a same DMRS pattern, or have antenna ports that are mapped on non-overlapping resource elements.
13 . The method of claim 11 , wherein the user devices include multiple second type of the user devices only or multiple first type of the user devices only.
14 . The method of claim 11 , wherein the first antenna port indication includes at least one of an antenna port index, a number of CDM group without data, or an index of CDM group without data, or the first antenna port indication is indicated using a radio resource control (RRC) signaling or a MAC control element, or a downlink control information.
15 . An apparatus for wireless communication comprising at least one processor and a memory, wherein the at least one processor is configured to read instructions from the memory and implement a method including:
receiving an antenna port indication indicating one from multiple demodulation reference signal (DMRS) port indications that include i) a first DMRS port indication corresponding to a first type of a user device configured to operate according to a first antenna port configuration and ii) a second DMRS port indication corresponding to a second type of a user device configured to operate according to a second antenna port configuration, the apparatus being either the first type of the user device or the second type of the user device; and
determining a first demodulation reference signal (DMRS) port or a second DMRS port based on the antenna port indication, and
wherein the first DMRS port is mapped to two resource elements of one physical resource block on one OFDM (Orthogonal Frequency Division Multiplexing) symbol, and
wherein the second DMRS port is mapped to at least four resource elements of the physical resource block on the OFDM symbol.
16 . The apparatus of claim 15 , wherein the antenna port indication includes at least one of an antenna port index, a number of Code Division Multiplexing (CDM) group without data, or an index of CDM group without data,
wherein the antenna port indication indicates whether a DMRS port is mapped on the two resource elements or more than two resource elements on the physical resource block on the OFDM (Orthogonal Frequency Division Multiplexing) symbol, and
wherein the antenna port index has a value in a range specific for the apparatus configured according to an antenna port configuration, the range being different from that for another communication device configured according to a legacy configuration.
17 . The apparatus of claim 15 , where the antenna port indication is indicated using a radio resource control (RRC) signaling or a MAC control element, or a downlink control information.
18 . The apparatus of claim 15 , wherein the two resource elements are at least one of: 1) continuous in frequency domain for DMRS type 2, or 2) comb in frequency domain for DMRS type 1, or wherein the first DMRS port has a sequence associated with at least one of a max number of CDM groups based on whether the first DMRS port corresponds to DMRS type 1 or DMRS type 2, or an index of a resource element.
19 . The apparatus of claim 15 , wherein the first DMRS port is determined by the first type of the user device and the first DMRS port is scheduled with at least one of:
1) An additional first DMRS port;
2) A second DMRS port mapped on at least four resource elements on the physical resource block of the OFDM symbol, wherein the at least four resource elements are overlapping with the two resource elements to which the first DMRS port maps, wherein a CDM group of the second DMRS port is scheduled on resource elements overlapping with at least one of: 1) three CDM groups of the first DMRS port for DMRS type 1, or 2) two CDM groups of the first DMRS port for DMRS type 2; or
3) A second DMRS port mapped on 4 resource elements non-overlapping with the two resource elements of the first DMRS port.