Enhanced physical downlink control channel scrambling and demodulation reference signal sequence generation
Methods, apparatuses, and systems are described to provide enhanced physical downlink control channel scrambling and demodulation reference signal sequence generation.
1. An apparatus to be employed in a user equipment (UE), the apparatus comprising:
channel estimation circuitry to
receive a reference signal sequence for a first antenna port on an orthogonal frequency division multiplexing (OFDM) symbol, and
estimate a channel for the first antenna port for the UE based on the received reference signal sequence and an assumption that the reference signal sequence is transmitted to another UE for a second antenna port;
channel compensation circuitry coupled with the channel estimation circuitry to receive an estimate of the channel and compensate a received signal; and
decoding circuitry to perform a blind decoding operation for enhanced physical downlink control channel (EPDCCH) based on the assumption and a scrambling initialization seed c int given by
c int =└n s /2┘*2 9 +N ID ePDCCH ,
where n s is a slot number within a radio frame and N ID ePDCCH is a virtual cell identifier that corresponds to an EPDCCH set in which downlink control information (DCI) is transmitted.
2. The apparatus of claim 1 , wherein the channel estimation circuitry is to perform a de-spreading operation on a received signal based on the assumption.
3. The apparatus of claim 2 , wherein the de-spreading operation is based on an orthogonal cover code.
4. The apparatus of claim 1 , wherein the channel compensation circuitry is to compensate the received signal based on the estimate of the channel.
5. The apparatus of claim 1 , wherein the reference signal sequence is r(m) and is given by:
r
(
m
)
=
1
2
(
1
-
2
*
c
(
2
m
)
)
+
j
1
2
(
1
-
2
*
c
(
2
m
+
1
)
,
where
m
=
{
0
,
1
,
…
,
96
N
RB
max
,
DL
-
1
normal
cyclic
prefix
0
,
1
,
…
,
128
N
RB
max
,
DL
-
1
extended
cyclic
prefix
.
6. One or more non-transitory, computer-readable media having instructions that, when executed, cause a user equipment (UE) to:
receive a reference signal sequence for a first antenna port on an orthogonal frequency division multiplexing (OFDM) symbol;
estimate a channel for the first antenna port for the UE based on the received reference signal sequence and an assumption that the reference signal sequence is transmitted to another UE for a second antenna port;
receive an estimate of the channel and compensate a received signal; and
blindly decode an enhanced physical downlink control channel (EPDCCH) based on the assumption and a scrambling initialization seed c int given by
c int =└n s /2┘*2 9 +N ID ePDCCH ,
where n s is a slot number within a radio frame and N ID ePDCCH is a virtual cell identifier that corresponds to an EPDCCH set in which downlink control information (DCI) is transmitted.
7. The one or more non-transitory, computer-readable media of claim 6 , having instructions that, when executed, cause a user equipment to perform a de-spreading operation on a received signal based on the assumption.
8. The one or more non-transitory, computer-readable media of claim 7 , wherein the de-spreading operation is based on an orthogonal cover code.
9. The one or more non-transitory, computer-readable media of claim 6 , having instructions that, when executed, cause a user equipment to compensate the received signal based on the estimate of the channel.
10. The one or more non-transitory, computer-readable media of claim 6 , wherein the reference signal sequence is r(m) and is given by:
r
(
m
)
=
1
2
(
1
-
2
*
c
(
2
m
)
)
+
j
1
2
(
1
-
2
*
c
(
2
m
+
1
)
,
where
m
=
{
0
,
1
,
…
,
96
N
RB
max
,
DL
-
1
normal
cyclic
prefix
0
,
1
,
…
,
128
N
RB
max
,
DL
-
1
extended
cyclic
prefix
.
11. One or more non-transitory, computer-readable media having instructions that, when executed, cause a user equipment (UE) to:
determine a reference signal sequence received for a first antenna port for communications between the UE and an enhanced node B is also used for communications of a second antenna port; and
perform a blind decoding operation for enhanced physical downlink control channel (EPDCCH) based on said determination and a scrambling initialization seed c int given
c int =└n s /2┘*2 9 +N ID ePDCCH ,
where n s is a slot number within a radio frame and N ID ePDCCH is a virtual cell identifier that corresponds to an enhanced physical downlink control channel (EPDCCH) set in which downlink control information (DCI) is transmitted.
12. The one or more non-transitory, computer-readable media of claim 11 , wherein the instructions, when executed, further cause the user equipment to:
process the reference signal sequence for the first antenna port on an orthogonal frequency division multiplexing (OFDM) symbol; and
estimate a channel for the first antenna port for the UE based on the reference signal sequence and determination that the reference signal sequence is also used for communications of a second antenna port.
13. The one or more non-transitory, computer-readable media of claim 12 , wherein the instructions, when executed, further cause the user equipment to:
compensate a received signal based on the estimate of the channel.
14. An apparatus to be employed in a user equipment (UE), the apparatus comprising circuitry to:
receive a reference signal sequence for a first antenna port on an orthogonal frequency division multiplexing (OFDM) symbol,
estimate a channel for the first antenna port for the UE based on the received reference signal sequence and determination that the reference signal sequence is transmitted to another UE for a second antenna port; and
perform a blind decoding operation based on the determination and a scrambling initialization seed c int given by
c int =└n s /2┘*2 9 +N ID ePDCCH ,
where n s is a slot number within a radio frame and N ID ePDCCH is a virtual cell identifier that corresponds to an enhanced physical downlink control channel (EPDCCH) set in which downlink control information (DCI) is transmitted.
15. The apparatus of claim 14 , further comprising circuitry to receive an estimate of the channel and compensate a received signal.
16. The apparatus of claim 14 , wherein the circuitry is further to perform a de-spreading operation on a received signal based on the determination.
17. The apparatus of claim 16 , wherein the de-spreading operation is based on an orthogonal cover code.
18. The apparatus of claim 14 , wherein the circuitry is further to compensate a received signal based on the estimate of the channel.