User equipment (UE)-specific assignment of demodulation reference signal (DMRS) sequences to support uplink (UL) coordinated multipoint (CoMP)

• US 8,811,144 B2
• Filed: 06/29/2012
• Issued: 08/19/2014
• Est. Priority Date: 11/04/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Chatterjee, Debdeep, Papathanassiou, Apostolos, Azizi, Shahrnaz
• Primary Examiner(s): ABELSON, RONALD B
• Application Number:
  US13/537,979
• Publication Number:
  US 20130114523A1
• Time in Patent Office: 781 Days
• Field of Search: 370/203, 370/208, 370/328, 370/329
• US Class Current: 370/208
• CPC Class Codes: H04J 11/0053 using co-ordinated multipoint transmission/reception co-ordinated antenna or beam-forming aspects H04B7/022
• CPC Class Codes: H04L 1/0077 Cooperative coding
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal

Abstract

Technology for user equipment (UE)-specific assigning of demodulation reference signal (DM-RS) sequences to support uplink (UL) coordinated multipoint (CoMP) is disclosed. One method can include a DM-RS sequence assignment device sorting the plurality of UE into a list according to a number of reception point (RP) links for each UE in a CoMP set, and assigning a base DM-RS sequence and a cyclic shift (CS) to a top-ranked UE from the list. The top-ranked UE can have a highest number of RP links. The DM-RS sequence assignment device can repeatedly assign a different CS of the base DM-RS sequence to a plurality of unassigned UE in a same cell as the top-ranked UE, and repeatedly assign the different CS of the base DM-RS sequence to a plurality of unassigned UE in a cooperatively served cell of the top-ranked UE.

Claims

1. At least one non-transitory machine readable storage medium comprising a plurality of instructions adapted to be executed to implement the method for user equipment (UE)-specific assigning of demodulation reference signal (DM-RS) sequences to support uplink (UL) coordinated multipoint (CoMP), comprising:

sorting the plurality of UE into a list according to a number of reception point (RP) links for each UE of a plurality of UE in a CoMP set;

assigning a DM-RS base sequence and a cyclic shift (CS) to a top-ranked UE from the list, wherein the top-ranked UE has a highest number of RP links;

repeatedly assigning a different CS of the DM-RS base sequence to a plurality of unassigned UE in a same cell as the top-ranked UE when the different CS of the DM-RS base sequence is available, wherein each DM-RS base sequence includes a plurality of CS; and

repeatedly assigning the different CS of the DM-RS base sequence to a plurality of unassigned UE in a cooperatively served cell of the top-ranked UE when the different CS of the DM-RS base sequence is available for each UE in the cooperatively served cell of the top-ranked UE, wherein the cooperatively served cell of the top-ranked UE is a cell within the CoMP set that has a scheduled UE that is cooperatively served by the home cell of the top-ranked UE.

2. The machine readable storage medium of claim 1, further comprising:

assigning a different DM-RS base sequence and a CS to a next top-ranked UE from the list when the different CS of the DM-RS base sequence is not available for each UE in the cooperatively served cell of the top-ranked UE, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list;

repeatedly assigning a different cyclic shift (CS) of the different DM-RS base sequence to a plurality of unassigned UE in a home cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available; and

repeatedly assigning a different CS of the different DM-RS base sequence to the plurality of unassigned UE in the cooperatively served cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available, wherein a cooperatively served cell of the next top-ranked UE is a cell within the CoMP set that has a scheduled UE that is cooperatively served by the home cell of the next top-ranked UE.

3. The machine readable storage medium of claim 1, wherein repeatedly assigning the different CS of the DM-RS base sequence to the plurality of unassigned UE is based on a descending order of a long-term channel power gain of each UE to a corresponding home cell of the UE or a substantially equivalent metric.

4. The machine readable storage medium of claim 1, further comprising:

reserving a set of N DM-RS base sequences for the CoMP set, wherein N represents an integer that is at least greater than or equal to a maximum number of co-scheduled UE in the CoMP set divided by a number of available CS for each DM-RS base sequence, wherein the set of N DM-RS base sequences includes the DM-RS base sequences generated by the physical cell identifier (PCI) of the cells within the CoMP set.

5. The machine readable storage medium of claim 1, further comprising:

removing a UE from the list when the DM-RS base sequence and the CS are assigned to the UE.

7. The machine readable storage medium of claim 1, further comprising:

repeatedly assigning the different CS of the DM-RS base sequence to a plurality of unassigned UE in a cooperatively serving cell of the top-ranked UE when the different CS of the DM-RS base sequence is available for each UE in the cooperatively serving cell of the top-ranked UE, wherein the cooperatively serving cell of a UE is a cell belonging to a CoMP RP set of the UE and is different from the UE'"'"'s home cell.

8. The machine readable storage medium of claim 7, further comprising:

selecting a next top-ranked UE from the list, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list; and

repeatedly assigning the different CS of the DM-RS base sequence to a plurality of remaining unassigned UE in a CoMP set when the different CS of the DM-RS base sequence is available for each remaining unassigned UE in the CoMP set, and when the next top-ranked UE has at least two cells in a next top-ranked UE'"'"'s CoMP RP set.

9. The machine readable storage medium of claim 7, further comprising:

selecting a next top-ranked UE from the list, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list; and

assigning a different DM-RS base sequence and a CS to the next top-ranked UE when the different CS of the DM-RS base sequence is not available for each remaining unassigned UE in a CoMP set, and when the next top-ranked UE has at least two cells in the next top-ranked UE'"'"'s CoMP RP set; and

repeatedly assigning a different CS of the different DM-RS base sequence to the plurality of remaining unassigned UE in a next top-ranked UE'"'"'s home cell, a next top-ranked UE'"'"'s cooperatively served cell, and then a next top-ranked UE'"'"'s cooperatively serving cells when the different CS of the different DM-RS base sequence is available.

10. The machine readable storage medium of claim 7, further comprising:

selecting a next top-ranked UE from the list, wherein the next top-ranked UE has A highest number of RP links from remaining UE on the list; and

repeatedly assigning the different CS of the DM-RS base sequence to a plurality of unassigned UE in a home cell of the next top-ranked UE when the different CS of the DM-RS base sequence is available for each unassigned UE in the home cell, and when the next top-ranked UE has only one cell in a next top-ranked UE'"'"'s CoMP RP set or the next top-ranked UE is not configured for UL CoMP.

11. The machine readable storage medium of claim 7, further comprising:

selecting a next top-ranked UE from the list, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list;

assigning a new DM-RS base sequence and a CS to the next top-ranked UE when the different CS of the DM-RS base sequence is not available for each unassigned UE in the home cell of the next-top ranked UE, wherein the next top-ranked UE has only one cell in a next top-ranked UE'"'"'s CoMP RP set or the next top-ranked UE is not configured for UL CoMP; and

repeatedly assigning a different CS of the new DM-RS base sequence to the plurality of remaining unassigned UE in a next top-ranked UE'"'"'s home cell, a next top-ranked UE'"'"'s cooperatively served cell, and then a next top-ranked UE'"'"'s cooperatively serving cells when the different CS of the new DM-RS base sequence is available.

12. The machine readable storage medium of claim 1, wherein the DM-RS base sequence is determined based on a virtual cell identifier (VCID).

13. The machine readable storage medium of claim 1, wherein the number of CS for each DM-RS base sequence is less than or equal to the number that is determined by a specific number of bits used to indicate the CS choice in an uplink-related downlink control information (DCI) format.

14. The machine readable storage medium of claim 1, further comprising:

applying the DM-RS base sequence and the CS in a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH) for a specific UE in the CoMP set.

6. The machine readable storage medium of claim l , further comprising:

assigning a different DM-RS base sequence and a CS to a next top-ranked UE from the list when the different CS of the DM-RS base sequence is not available for each UE in a cooperatively serving cell of the top-ranked UE, wherein the cooperatively serving cell of a UE is a cell belonging to a CoMP RP set of the UE and is different from the UE'"'"'s home cell, and the next top-ranked UE has a highest number of RP links from remaining UE on the list;

repeatedly assigning a different cyclic shift (CS) of the different DM-RS base sequence to a plurality of unassigned UE in a home cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available; and

repeatedly assigning a different CS of the different DM-RS base sequence to the plurality of unassigned UE in the cooperatively served cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available, wherein a cooperatively served cell of the next top-ranked UE is a cell within the CoMP set that has a scheduled UE that is cooperatively served by the home cell of the next top-ranked UE.

15. A demodulation reference signal (DM-RS) sequence assignment device to support uplink (UL) coordinated multipoint (CoMP), comprising:

a sorting module configured to sort the plurality of UE into a list according to a number of reception point (RP) links for each UE of a plurality of UE in a CoMP set; and

a DM-RS sequence assignment module configured to assign a DM-RS base sequence and CS to a top-ranked UE from the list, wherein the top-ranked UE has a highest number of RP links, and

further configured to repeatedly assign a different cyclic shift (CS) of the DM-RS base sequence to a plurality of unassigned UE in a same cell as the top-ranked UE when the different CS of the DM-RS base sequence is available, wherein each DM-RS base sequence includes a plurality of CS, and

repeatedly assign the different CS of the DM-RS base sequence to a plurality of unassigned UE in a cooperatively served cell of the top-ranked UE when the different CS of the DM-RS base sequence is available for each UE in the cooperatively served cell of the top-ranked UE, wherein the cooperatively served cell of the top-ranked UE is a cell within the CoMP set that has a scheduled UE that is cooperatively served by the home cell of the top-ranked UE.

16. The DM-RS sequence assignment device of claim 15, wherein DM-RS sequence assignment module is further configured to:

assign a different DM-RS base sequence and a CS to a next top-ranked UE from the list when the different CS of the DM-RS base sequence is not available for each UE in the cooperatively served cell of the top-ranked UE, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list;

repeatedly assign a different cyclic shift (CS) of the different DM-RS base sequence to a plurality of unassigned UE in a home cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available; and

repeatedly assign a different CS of the different DM-RS base sequence to the plurality of unassigned UE in the cooperatively served cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available, wherein a cooperatively served cell of the next top-ranked UE is a cell within the CoMP set that has a scheduled UE that is cooperatively served by the home cell of the next top-ranked UE.

17. The DM-RS sequence assignment device of claim 15, wherein the sorting module is further configured to sort the plurality of unassigned UE based on a descending order of a long-term channel power gain of each UE to a corresponding home cell of the UE or a substantially equivalent metric prior to the DM-RS sequence assignment module repeatedly assigning the different CS of the new DM-RS base sequence.

18. The DM-RS sequence assignment device of claim 15, wherein DM-RS sequence assignment module is further configured to:

reserve a set of N DM-RS base sequences for the CoMP set, wherein N represents an integer that is at least greater than or equal to a maximum number of co-scheduled UE in the CoMP set divided by a number of available CS for each DM-RS base sequence, wherein the set of N DM-RS base sequences includes the DM-RS base sequences generated by the physical cell identifier (PCI) of the cells within the CoMP set.

19. The DM-RS sequence assignment device of claim 15, wherein DM-RS sequence assignment module is further configured to:

remove a UE from the list when the DM-RS base sequence and the CS are assigned to the UE.

20. The DM-RS sequence assignment device of claim 15, wherein DM-RS sequence assignment module is further configured to:

repeatedly assign the different CS of the DM-RS base sequence to a plurality of unassigned UE in a cooperatively serving cell of the top-ranked UE when the different CS of the DM-RS base sequence is available for each UE in the cooperatively serving cell of the top-ranked UE, wherein the cooperatively serving cell of a UE is a cell belonging to a CoMP RP set of the UE and is different from the UE'"'"'s home cell;

assign a different DM-RS base sequence and a CS to a next top-ranked UE from the list when the different CS of the DM-RS base sequence is not available for each UE in a cooperatively serving cell of the top-ranked UE, and the next top-ranked UE has a highest number of RP links from remaining UE on the list,

repeatedly assign a different cyclic shift (CS) of the different DM-RS base sequence to a plurality of unassigned UE in a home cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available; and

repeatedly assign a different CS of the different DM-RS base sequence to the plurality of unassigned UE in the cooperatively served cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available.

21. The DM-RS sequence assignment device of claim 15, wherein DM-RS sequence assignment module is further configured to:

select a next top-ranked UE from the list, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list;

repeatedly assign the different CS of the DM-RS base sequence to a plurality of remaining unassigned UE, in a CoMP set when the different CS of the DM-RS base sequence is available for each remaining unassigned UE in the CoMP set, and when the next top-ranked UE has at least two cells in a next top-ranked UE'"'"'s CoMP RP set;

assign a different DM-RS base sequence and a CS to the next top-ranked UE when the different CS of the DM-RS base sequence is not available for each remaining unassigned UE in a CoMP set, and when the next top-ranked UE has at least two cells in the next top-ranked UE'"'"'s CoMP RP set, and

repeatedly assign a different CS of the different DM-RS base sequence to the plurality of remaining unassigned UE in a next top-ranked UE'"'"'s home cell, a next top-ranked UE'"'"'s cooperatively served cell, and then a next top-ranked UE'"'"'s cooperatively serving cells when the different CS of the different DM-RS base sequence is available.

22. The DM-RS sequence assignment device of claim 15, wherein DM-RS sequence assignment module is further configured to:

select a next top-ranked UE from the list, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list;

repeatedly assign the different CS of the DM-RS base sequence to a plurality of unassigned UE in a home cell of the next top-ranked UE when the different CS of the DM-RS base sequence is available for each unassigned UE in the home cell, and when the next top-ranked UE has only one cell in a next top-ranked UE'"'"'s CoMP RP set or the next top-ranked UE is not configured for UL CoMP;

assign anew DM-RS base sequence and a CS to the next top-ranked UE when the different CS of the DM-RS base sequence is not available for each unassigned UE the home cell of the next-top ranked UE, and

repeatedly assign a different CS of the new DM-RS base sequence to the plurality of remaining unassigned UE in a next top-ranked UE'"'"'s home cell, a next top-ranked UE'"'"'s cooperatively served cell, and then a next top-ranked UE'"'"'s cooperatively serving cells when the different CS of the new DM-RS base sequence is available.

23. The DM-RS sequence assignment device of claim 15, wherein the UE is configured to connect to at least one of a wireless local area network (WLAN), a wireless personal area network (WPAN), and a wireless wide area network (WWAN), wherein the UE includes an antenna, a touch sensitive display screen, a speaker, a microphone, a graphics processor, an application processor, internal memory, a non-volatile memory port, or combinations thereof.

24. The DM-RS sequence assignment device of claim 15, wherein the DM-RS sequence assignment device is included in an evolved packet core (EPC) or a node, wherein the node is selected from the group consisting of a base station (BS), a Node B (NB), an evolved Node B (eNB), a baseband unit (BBU), a remote radio head (RRH), a remote radio equipment (RRE), a remote radio unit (RRU), and combinations thereof,

25. A method for user equipment (UE)-specific assigning of demodulation reference signal (DM-RS) sequences to support uplink (UL) coordinated multipoint (CoMP), comprising:

determining a number of reception point (RP) links for each UE of a plurality of UE scheduled for uplink transmission in a CoMP set;

sorting the plurality of UE into a list according to a number of reception point (RP) links for each UE of a plurality of UE in a CoMP set;

assigning a DM-RS base sequence and a cyclic shift (CS) to a top-ranked UE from the list, wherein the top-ranked UE has a highest number of RP links;

repeatedly assigning a different CS of the DM-RS base sequence to a plurality of unassigned UE in a same cell as the top-ranked UE when the different CS of the DM-RS base sequence is available, wherein each DM-RS base sequence includes a plurality of CS; and

repeatedly assigning the different CS of the DM-RS base sequence to a plurality of unassigned UE a cooperatively served cell of the top-ranked UE when the different CS of the DM-RS base sequence is available for each UE in the cooperatively served cell of the top-ranked UE, wherein the cooperatively served cell of the top-ranked UE is a cell within the CoMP set that has a scheduled UE that is cooperatively served by the home cell of the top-ranked UE.

26. The method of claim 25, further comprising:

assigning a different DM-RS base sequence and a CS to a next top-ranked UE from the list when the different CS of the DM-RS base sequence is not available for each UE in the cooperatively served cell of the top-ranked UE, wherein the next top-ranked UE has a highest number of RP links from remaining UE on the list;

repeatedly assigning a different cyclic shift (CS) of the different DM-RS base sequence to a plurality of unassigned UE in a home cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available; and

repeatedly assigning a different CS of the different DM-RS base sequence to the plurality of unassigned UE in the cooperatively served cell of the next top-ranked UE when the different CS of the different DM-RS base sequence is available, wherein a cooperatively served cell of the next top-ranked UE is a cell within the CoMP set that has a scheduled UE that is cooperatively served by the home cell of the next top-ranked UE.