Method for generating reference signals

• US 8,526,385 B2
• Filed: 08/02/2011
• Issued: 09/03/2013
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Berggren, Fredrik, Liu, Jianghua
• Primary Examiner(s): Moore, Ian N
• Assistant Examiner(s): Alexander, Jenee
• Application Number:
  US13/196,667
• Publication Number:
  US 20110286423A1
• Time in Patent Office: 763 Days
• Field of Search: 370/328, 370/329, 370/330, 370/331, 370/344, 455/509
• US Class Current: 370/329
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005

Abstract

The present disclosure relates to a method for generating reference signals in a cellular wireless communication system having a set of resource blocks. Each resource block includes a plurality of resource elements. Each reference signal is associated with an antenna port in a cell. At least one reference signal in a cell is transmitted on at least one resource element only in resource blocks belonging to a subset of said set of resource blocks. The method includes shifting frequency in the resource blocks in the subset of resource blocks. The frequency shifting of the resource blocks belonging to said subset of resource blocks is cell-specific and is determined from an integer sequence having a length less than or equal to a total number of cell identities in said cellular wireless communication system. The disclosure also relates to methods and devices for transmitting and receiving such reference signals; and to a device for generating reference signals.

Claims

1. A method for generating reference signals in a cellular wireless communication system having a set of resource blocks, each resource block comprising a plurality of resource elements, each reference signal being associated with an antenna port in a cell, and wherein at least one reference signal in a cell is transmitted on at least one resource element only in resource blocks belonging to a subset of said set of resource blocks, said method comprising:

frequency shifting the resource blocks belonging to said subset of resource blocks , wherein the frequency shifting of the resource blocks belonging to said subset of resource blocks is cell-specific and is determined from an integer sequence having a length less than or equal to a total number of cell identities in said cellular wireless communication system;

wherein said integer sequence is periodic, having a sequence length equal to said total number of cell identities and comprises elements from a set having v_shift^RB number of elements, wherein v_shift^RB denotes the total number of frequency shifts, of the resource blocks belonging to said subset of resource blocks , in number of resource blocks.

2. The method for generating reference signals according to claim 1, further comprising:

frequency shifting at least one resource element , on which said at least one reference signal is to be transmitted, within each resource block belonging to said subset of resource blocks , wherein the frequency shifting of said at least one resource element is cell-specific.

3. The method for generating reference signals according to claim 2, wherein resource elements , on which reference signals associated with different antenna ports in a cell, are frequency shifted differently within resource blocks belonging to said subset and/or said set of resource blocks.

4. The method for generating reference signals according to claim 1, wherein said reference signals are obtained from a reference signal sequence common to all antenna ports in a cell and unique for said cell.

5. The method for generating reference signals according to claim 1, wherein said integer sequence is determined from the set of cell identities.

6. The method for generating reference signals according to claim 1, wherein said integer sequence is determined from one of the following:

7. The method for generating reference signals according to claim 1, wherein said integer sequence at a time instant n is given by:

{tilde over (v)}_shift^RB(n,N_ID^cell)=v_shift^RB(N_ID^cell)+v(n), or

{tilde over (v)}_shift^RB(n,N_ID^cell)=v_shift^RB(N_ID^cell)+v(n,N_ID^cell),

where v_shift^RB(N_ID^cell) is a function of the cell identity, v(n) denotes a predetermined offset sequence for said cellular wireless communication system, and v(n, N_ID^cell) denotes a cell-specific offset sequence, respectively.

8. The method for generating reference signals according to claim 1, wherein the frequency shifting of the resource blocks belonging to said subset of resource blocks is performed so that the number of reference signals in each resource block belonging to said subset of resource blocks is the same.

9. The method for generating reference signals according to claim 1, wherein reference signals associated with different antenna ports in a cell are transmitted in the same, or different resource blocks belonging to said subset of resource blocks.

10. The method for generating reference signals according to claim 1, wherein a representation of said integer sequence is explicitly signalled in said cellular wireless communication system, or implicitly determined from the cell identity.

11. The method for generating reference signals according to claim 1, wherein reference signals for different cells are transmitted in different sub-frames, radio frames, slots or OFDM symbols.

12. The method for generating reference signals according to claim 1, wherein said reference signals are employed for channel estimation and/or demodulation in the downlink, and/or said cellular wireless communication system is a long term evolution, LTE, communication system or a long term evolution advanced, LTE-A, communication system.

13. A device for generating reference signals for a cellular wireless communication system having a set of resource blocks, each resource block comprising a plurality of resource elements, comprising:

a processor configured to shift frequency in the resource blocks belonging to a subset of resource blocks, wherein each reference signal is associated with an antenna port in a cell, and wherein at least one reference signal in a cell is transmitted on at least one resource element only in resource blocks belonging to said subset of said set of resource blocks, and wherein the frequency shifting of the resource blocks belonging to said subset of resource blocks is cell-specific and is determined from an integer sequence having a length less than or equal to a total number of cell identities in said cellular wireless communication system;

wherein said integer sequence is periodic, having a sequence length equal to said total number of cell identities and comprises elements from a set having v_shift^RB number of elements, wherein v_shift^RB denotes the total number of frequency shifts, of the resource blocks belonging to said subset of resource blocks , in number of resource blocks.