Apparatus and method for UE-specific demodulation reference signal scrambling
A user equipment (UE) is configured to communicate with a plurality of base stations in a wireless network. The UE includes a processor that receive a downlink grant scheduling a physical downlink shared channel (PDSCH) for the UE, the downlink grant being transmitted in a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (ePDCCH). The processor also receives UE-specific demodulation reference signals (UE-RS) provided for demodulation of the PDSCH, wherein the UE-RS are scrambled according to a scrambling sequence initialized with an initialization value c init . The downlink grant includes a one-bit scrambling identifier (SCID) information field configured to indicate a pair of values comprising a scrambling identifier n SCID and a virtual cell ID N v-ID cell out of two candidate pairs, the pair of values to be used for determining the initialization value c init for the UE-RS.
1. For use in a user equipment (UE) configured to communicate with a plurality of base stations in a wireless network, a method comprising:
receiving a downlink grant scheduling a physical downlink shared channel (PDSCH) for the UE, the downlink grant being transmitted in a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (ePDCCH); and
receiving UE-specific demodulation reference signals (UE-RS) provided for demodulation of the PDSCH, wherein the UE-RS are scrambled according to a scrambling sequence initialized with an initialization value c init ,
wherein the downlink grant comprises a one-bit scrambling identifier (SCID) information field configured to indicate a pair of values comprising a scrambling identifier n SCID and a virtual cell ID N v-ID cell out of two candidate pairs, the pair of values to be used for determining the initialization value c init for the UE-RS,
wherein c init is determined according to the equation
c init =(└ n s /2┘+1)·(2 N v-ID cell +1)·2 16 +n SCID
where n s is a slot number.
2. The method of claim 1 , wherein the SCID information field in the downlink grant replaces a SCID field in a standard 3GPP LTE DCI format 2B or DCI format 2C downlink grant.
3. The method of claim 1 , wherein the two candidate pairs of values are associated with two radio resource control (RRC)-configured values, RRC_SCID0 and RRC_SCID1, wherein each of RRC_SCID0 and RRC_SCID1 comprises a pair of values for (N v-ID cell , n SCID ).
4. The method of claim 1 , wherein the two candidate pairs of values for N v-ID cell , n SCID ) comprise (N v-ID,0 cell , 0) and (N v-ID,1 cell , 1), wherein N v-ID,0 cell and N v-ID,1 cell are RRC-configured.
5. The method of claim 1 , further comprising:
transmitting a hybrid automatic repeat request acknowledgement signal (HARQ-ACK) in a physical uplink channel (PUCCH) selected among a plurality of PUCCHs, wherein the plurality of PUCCHs are partitioned into a plurality of zones, wherein a first of the zones is associated with a first UE-specific uplink reference signal (UL RS) base sequence and a second of the zones is associated with a second UE-specific UL RS base sequence.
6. The method of claim 5 , wherein the first PUCCH zone is indicated by a first value of the SCID and the second PUCCH zone is indicated by a second value of the SCID.
7. The method of claim 5 , wherein the index of the PUCCH for the HARQ-ACK is determined according to the equation
n PUCCH (1) =n CCE +n offset +N PUCCH (1)
where N PUCCH (1) is RRC configured, n CCE is a smallest control channel element (CCE) number of the PDCCH, and n offset is an offset value selected among a plurality of predetermined candidate values.
8. The method of claim 7 , wherein a first of the plurality of predetermined candidate values is indicated by a first value of the SCID and a second of the plurality of predetermined candidate values is indicated by a second value of the SCID.
9. The method of claim 7 , wherein the plurality of predetermined candidate values are RRC configured.
10. A user equipment (UE) configured to communicate with a plurality of base stations in a wireless network, the user equipment comprising:
a processor configured to:
receive a downlink grant scheduling a physical downlink shared channel (PDSCH) for the UE, the downlink grant being transmitted in a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (ePDCCH); and
receive UE-specific demodulation reference signals (UE-RS) provided for demodulation of the PDSCH, wherein the UE-RS are scrambled according to a scrambling sequence initialized with an initialization value c init ,
wherein the downlink grant comprises a one-bit scrambling identifier (SCID) information field configured to indicate a pair of values comprising a scrambling identifier n SCID and a virtual cell ID N v-ID cell out of two candidate pairs, the pair of values to be used for determining the initialization value c init for the UE-RS,
wherein c init is determined according to the equation
c init =(└ n s /2┘+1)·(2 N v-ID cell +1)·2 16 +n SCID
where n s is a slot number.
11. The UE of claim 10 , wherein the SCID information field in the downlink grant replaces a SCID field in a standard 3GPP LTE DCI format 2B or DCI format 2C downlink grant.
12. The UE of claim 10 , wherein the two candidate pairs of values are associated with two radio resource control (RRC)-configured values, RRC_SCID0 and RRC_SCID1, wherein each of RRC_SCID0 and RRC_SCID1 comprises a pair of values for (N v-ID cell , n SCID ).
13. The UE of claim 10 , wherein the two candidate pairs of values for (N v-ID cell , n SCID ) comprise (N v-ID,0 cell , 0), and (N v-ID,1 cell , 1), wherein N v-ID,0 cell and N v-ID,1 cell are RRC-configured.
14. The UE of claim 10 , the processor further configured to:
transmit a hybrid automatic repeat request acknowledgement signal (HARQ-ACK) in a physical uplink channel (PUCCH) selected among a plurality of PUCCHs, wherein the plurality of PUCCHs are partitioned into a plurality of zones, wherein a first of the zones is associated with a first UE-specific uplink reference signal (UL RS) base sequence and a second of the zones is associated with a second UE-specific UL RS base sequence.
15. The UE of claim 14 , wherein the first PUCCH zone is indicated by a first value of the SCID and the second PUCCH zone is indicated by a second value of the SCID.
16. The UE of claim 14 , wherein the index of the PUCCH for the HARQ-ACK is determined according to the equation
n PUCCH (1) =n CCE +n offset +N PUCCH (1)
where N PUCCH (1) is RRC configured, n CCE is a smallest control channel element (CCE) number of the PDCCH, and n offset is an offset value selected among a plurality of predetermined candidate values.
17. The UE of claim 16 , wherein a first of the plurality of predetermined candidate values is indicated by a first value of the SCID and a second of the plurality of predetermined candidate values is indicated by a second value of the SCID.
18. The UE of claim 16 , wherein the plurality of predetermined candidate values are RRC configured.
19. A base station configured for communication with a plurality of user equipments (UEs), the base station comprising:
a processor configured to:
transmit a downlink grant scheduling a physical downlink shared channel (PDSCH) for the UE, the downlink grant being transmitted in a physical downlink control channel (PDCCH) or an enhanced physical downlink control channel (ePDCCH); and
transmit UE-specific demodulation reference signals (UE-RS) provided for demodulation of the PDSCH, wherein the UE-RS are scrambled according to a scrambling sequence initialized with an initialization value c init ,
wherein the downlink grant comprises a one-bit scrambling identifier (SCID) information field configured to indicate a pair of values comprising a scrambling identifier n SCID and a virtual cell ID N v-ID cell out of two candidate pairs, the pair of values to be used for determining the initialization value c init for the UE-RS,
wherein c init is determined according to the equation
c init =(└ n s /2┘+1)·(2N v-ID cell +1)·2 16 +n SCID
where n s is a slot number.
20. The base station of claim 19 , wherein the SCID information field in the downlink grant replaces a SCID field in a standard 3GPP LTE DCI format 2B or DCI format 2C downlink grant.
21. The base station of claim 19 , wherein the two candidate pairs of values are associated with two radio resource control (RRC)-configured values, RRC_SCID0 and RRC_SCID1, wherein each of RRC_SCID0 and RRC_SCID1 comprises a pair of values for (N v-ID cell , n SCID ).
22. The base station of claim 19 , wherein the two candidate pairs of values for cell (N v-ID cell , n SCID ) comprise (N v-ID,0 cell , 0) and (N v-ID,1 cell , 1), wherein N v-ID,0 cell and N v-ID,1 cell are RRC-configured.
23. The base station of claim 19 , the processor further configured to:
receive a hybrid automatic repeat request acknowledgement signal (HARQ-ACK) in a physical uplink channel (PUCCH) selected among a plurality of PUCCHs, wherein the plurality of PUCCHs are partitioned into a plurality of zones, wherein a first of the zones is associated with a first UE-specific uplink reference signal (UL RS) base sequence and a second of the zones is associated with a second UE-specific UL RS base sequence.
24. The base station of claim 23 , wherein the first PUCCH zone is indicated by a first value of the SCID and the second PUCCH zone is indicated by a second value of the SCID.
25. The base station of claim 23 , wherein the index of the PUCCH for the HARQ-ACK is determined according to the equation
n PUCCH (1) =n CCE +n offset +N PUCCH (1)
where N PUCCH (1) is RRC configured, n CCE is a smallest control channel element (CCE) number of the PDCCH, and n offset is an offset value selected among a plurality of predetermined candidate values.
26. The base station of claim 25 , wherein a first of the plurality of predetermined candidate values is indicated by a first value of the SCID and a second of the plurality of predetermined candidate values is indicated by a second value of the SCID.
27. The base station of claim 25 , wherein the plurality of predetermined candidate values are RRC configured.