Calculation of a reference signal received power of a resynchronisation signal in LTE
This disclosure describes methods, systems, and devices for measuring a reference signal received power (RSRP) in a user equipment (UE) that operates in machine type communication (MTC). In one example, a method involves receiving, from a radio access network (RAN) serving the UE, a resynchronization signal (RSS). The method also involves calculating a reference signal received power (RSRP) of the RSS.
1. A method comprising:
receiving, from a radio access network (RAN), a resynchronization signal (RSS); and
calculating a reference signal received power (RSRP) of the RSS using an equation comprising:
RSRP
ResourceBlock
(
RB
)
=
1
2
(
M
-
1
)
absolute
value
{
∑
i
=
1
2
∑
k
=
1
M
-
1
y
(
i
,
k
)
·
complex
conjugate
(
y
(
i
,
k
+
1
)
)
}
,
wherein y(i,k) is a respective portion of the RSS at an i-th subcarrier and k-th symbol, M is a symbol number in an RSS duration, and M has a value greater than 1.
2. The method of claim 1 , wherein the RSS is a first RSS, the RSRP is a first RSRP, and the equation is a first equation, and wherein the method further comprises:
receiving a second RSS from the RAN; and
calculating a second RSRP of the second RSS based on a second equation comprising a frequency domain scalar product.
3. The method of claim 2 , wherein the second equation comprises:
RSRP
RB
=
1
2
(
M
-
1
)
absolute
value
{
∑
k
=
1
M
y
(
1
,
k
)
·
complex
conjugate
(
y
(
2
,
k
)
)
}
.
4. The method of claim 1 , wherein the RSS is a first RSS, the RSRP is a first RSRP, and the equation is a first equation, and wherein the method further comprises:
receiving a second RSS from the RAN; and
calculating a second RSRP of the second RSS based on a second equation comprising a frequency domain and time domain scalar product.
5. The method of claim 4 , wherein the second equation comprises:
RSRP
RB
=
1
4
(
M
-
1
)
absolute
value
{
∑
k
=
1
M
y
(
1
,
k
)
·
complex
conjugate
(
y
(
2
,
k
)
)
}
+
1
4
(
M
-
1
)
absolute
value
{
∑
i
=
1
2
∑
k
=
1
M
-
1
y
(
i
,
k
)
·
complex
conjugate
(
y
(
i
,
k
+
1
)
)
}
.
6. The method of claim 1 , further comprising:
receiving, from the RAN, a cell specific reference signal (CRS); and
combining the CRS with the RSS, wherein calculating the RSRP of the RSS comprises calculating the RSRP of the combined signal.
7. The method of claim 1 , wherein a duration of the RSS is based on a coverage enhancement (CE) level.
8. The method of claim 1 , wherein the RSS spans a plurality of subframes, and wherein calculating the RSRP of the RSS comprises:
calculating respective RSRPs of the plurality of subframes; and
calculating an average of the respective RSRPs.
9. A machine type communication (MTC) User Equipment (UE) comprising:
a radio front end module configured to receive, from a radio access network (RAN), a resynchronization signal (RSS); and
one or more processors configured to perform operations comprising calculating a reference signal received power (RSRP) of the RSS using an equation comprising:
RSRP
ResourceBlock
(
RB
)
=
1
2
(
M
-
1
)
absolute
value
{
∑
k
=
1
M
y
(
1
,
k
)
·
complex
conjugate
(
y
(
2
,
k
)
)
}
,
where y(i,k) is a respective portion of the RSS at an i-th subcarrier and k-th symbol, where i=1, 2, M is a symbol number in an RSS duration, and M has a value greater than 1.
10. The MTC UE of claim 9 , wherein the RSS is a first RSS, the RSRP is a first RSRP, and the equation is a first equation, and wherein the operations further comprise:
calculating a second RSRP of a second RSS based on a second equation comprising a time domain scalar product.
11. The MTC UE of claim 10 , wherein the second equation comprises:
RSRP
RB
=
1
2
(
M
-
1
)
absolute
value
{
∑
i
=
1
2
∑
k
=
1
M
-
1
y
(
i
,
k
)
·
complex
conjugate
(
y
(
i
,
k
+
1
)
)
}
.
12. The MTC UE of claim 9 , wherein the RSS is a first RSS, the RSRP is a first RSRP, and the equation is a first equation, and wherein the operations further comprise:
calculating a second RSRP of a second RSS based on a second equation comprising a frequency domain and time domain scalar product.
13. The MTC UE of claim 12 , wherein the second equation comprises:
RSRP
RB
=
1
4
(
M
-
1
)
absolute
value
{
∑
k
=
1
M
y
(
1
,
k
)
·
complex
conjugate
(
y
(
2
,
k
)
)
}
+
1
4
(
M
-
1
)
absolute
value
{
∑
i
=
1
2
∑
k
=
1
M
-
1
y
(
i
,
k
)
·
complex
conjugate
(
y
(
i
,
k
+
1
)
)
}
.
14. The MTC UE of claim 9 ,
wherein the front end module is further configured to receive, from the RAN, a cell specific reference signal (CRS), and wherein the operations further comprise:
combining the CRS with the RSS, wherein calculating the RSRP of the RSS comprises calculating the RSRP of the combined signal.
15. The MTC UE of claim 9 , wherein a duration of the RSS is based on a coverage enhancement (CE) level of the MTC UE.
16. One or more processors comprising: circuitry configured to perform operations comprising:
controlling a radio front end module to receive, from a radio access network (RAN), a resynchronization signal (RSS); and
calculating a reference signal received power (RSRP) of the RSS using an equation comprising:
RSRP
RB
=
1
4
(
M
-
1
)
absolute
value
{
∑
k
=
1
M
y
(
1
,
k
)
·
complex
conjugate
(
y
(
2
,
k
)
)
}
+
1
4
(
M
-
1
)
absolute
value
{
∑
i
=
1
2
∑
k
=
1
M
-
1
y
(
i
,
k
)
·
complex
conjugate
(
y
(
i
,
k
+
1
)
)
}
,
where y(i,k) is a respective portion of the RSS at an i-th subcarrier and k-th symbol, and M is a symbol number in an RSS duration and has a value greater than 1.
17. The one or more processors of claim 16 , wherein the RSS is a first RSS, the RSRP is a first RSRP, and the equation is a first equation, and wherein the operations further comprise:
controlling the radio front end module to receive a second RSS from the RAN; and
calculating a second RSRP of the second RSS based on a second equation comprising a time domain scalar product.
18. The one or more processors of claim 17 , wherein the second equation comprises:
RSRP
RB
=
1
2
(
M
-
1
)
absolute
value
{
∑
i
=
1
2
∑
k
=
1
M
-
1
y
(
i
,
k
)
·
complex
conjugate
(
y
(
i
,
k
+
1
)
)
}
.
19. The one or more processors of claim 16 , wherein the RSS is a first RSS, the RSRP is a first RSRP, and the equation is a first equation, and wherein the operations further comprise:
controlling the radio front end module to receive a second RSS from the RAN; and
calculating a second RSRP of the second RSS based on a second equation comprising a frequency domain scalar product.
20. The one or more processors of claim 19 , wherein the second equation comprises:
RSRP
RB
=
1
2
(
M
-
1
)
absolute
value
{
∑
k
=
1
M
y
(
1
,
k
)
·
complex
conjugate
(
y
(
2
,
k
)
)
}
.