Initialization of reference signal scrambling

• US 8,300,587 B2
• Filed: 03/01/2010
• Issued: 10/30/2012
• Est. Priority Date: 08/17/2009
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Chmiel, Mieszko, Chen, Peng, Koivisto, Tommi Tapani, Che, Xiang Guang, Roman, Timo Eric
• Primary Examiner(s): ABELSON, RONALD B
• Application Number:
  US12/715,353
• Publication Number:
  US 20110038310A1
• Time in Patent Office: 974 Days
• Field of Search: 370/328, 370/329, 370/437
• US Class Current: 370/329
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04L 27/2613 Structure of the reference signals

Abstract

A scrambling sequence is initialized using at least a cell identifier and an offset, and a physical downlink control information DCI is sent to a user equipment which indicates the offset. In more particular embodiments a user equipment-specific reference signal UE-RS is scrambled using the initialized scrambling sequence, and the scrambled UE-RS is sent to the UE for demodulating a downlink shared channel (PDSCH). In another exemplary embodiment the generated UE-RS is sent in a pilot part of a subframe transmission associated with the PDSCH and is for demodulating at least a data part of that subframe transmission. In a specific embodiment from the UE side, the UE receives the UE-RS and the DCI which indicates the offset, descrambles the UE-RS using a scrambling sequence that is initialized using a cell identifier and the indicated offset; and demodulates the PDSCH using the de-scrambled UE-RS.

Claims

1. A method comprising:

initializing a scrambling sequence using a cell identifier and a non-fixed offset; and

sending a physical downlink control information to a user equipment which indicates the offset.

2. The method according to claim 1, further comprising sending a user equipment specific reference signal to the user equipment for demodulating a downlink shared channel, wherein the user equipment specific reference signal is scrambled by the scrambling sequence.

3. The method according to claim 1, wherein the physical downlink control information is transmitted on a physical downlink shared control channel (PDCCH).

4. An apparatus comprising:

at least one processor; and

at least one memory storing computer program code configured to, with the at least one processor, cause the apparatus at least to perform;

initializing a scrambling sequence using a cell identifier and a non-fixed offset; and

sending a physical downlink control information to a user equipment which indicates the offset.

5. The apparatus according to claim 4, wherein the memory storing computer program code is configured with the at least one processor to cause the apparatus at least to further perform:

sending a user equipment specific reference signal to the user equipment for demodulating a downlink shared channel, wherein the user equipment specific reference signal is scrambled by the scrambling sequence.

6. The apparatus according to claim 4, wherein the offset corresponds to a single specific scrambling sequence.

7. The apparatus according to claim 4, wherein the physical downlink control information is transmitted on a physical downlink shared control channel (PDCCH).

8. The apparatus according to claim 4, wherein the cell identifier is selected from a set of coordinated multipoint transmission cell identifiers.

9. The apparatus according to claim 5, wherein the user equipment specific reference signal is sent to the user equipment in a pilot part of a subframe transmission associated with the physical downlink shared channel, and the user equipment specific reference signal is for demodulating at least a data part of the transmission associated with the physical downlink shared channel.

10. A memory storing computer program code that when executed by at least one processor result in operations comprising:

initializing a scrambling sequence using a cell identifier and a non-fixed offset; and

sending a physical downlink control information to a user equipment which indicates the offset.

11. The memory according to claim 10, the operations further comprising:

sending a user equipment specific reference signal to the user equipment for demodulating a downlink shared channel, wherein the user equipment specific reference signal is scrambled by the scrambling sequence.

12. A method comprising:

receiving a physical downlink control information which indicates a non-fixed offset; and

initializing a scrambling sequence using a cell identifier and the offset.

13. The method according to claim 12, further comprising receiving a user equipment specific reference signal for demodulating a downlink shared channel, wherein the user equipment specific reference signal is scrambled by the scrambling sequence.

14. The method according to claim 12, in which the physical downlink control information is received on a physical downlink shared control channel (PDCCH).

15. An apparatus comprising:

at least one processor; and

at least one memory storing computer program code configured to, with the at least one processor, cause the apparatus at least to perform;

receiving a physical downlink control information which indicates a non-fixed offset; and

initializing a scrambling sequence using a cell identifier and the offset.

16. The apparatus according to claim 15, wherein the memory storing computer program code is configured with the at least one processor to cause the apparatus at least to further perform:

receiving a user equipment specific reference signal for demodulating a downlink shared channel, wherein the user equipment specific reference signal is scrambled by the scrambling sequence.

17. The apparatus according to claim 15, wherein the offset corresponds to a single specific scrambling sequence.

18. The apparatus according to claim 15, wherein the physical downlink control information is received on a physical downlink shared control channel (PDCCH).

19. The apparatus according to claim 15, wherein the cell identifier comprises an identifier for one cell in a wireless network from which the downlink control information was received, and wherein the apparatus comprises a user equipment associated with a user specific reference signal that is scrambled by the scrambling sequence.

20. A memory storing computer program code that when executed by at least one processor result in operations comprising:

receiving downlink control information which indicates a non-fixed offset; and

initializing a scrambling sequence using a cell identifier and the offset.

21. The method according to claim 20, further comprising receiving a user equipment specific reference signal for demodulating a downlink shared channel, wherein the user equipment specific reference signal is scrambled by the scrambling sequence.