METHOD, TRANSCEIVER AND TELECOMMUNICATION SYSTEM FOR GENERATING REFERENCE SEQUENCE MATRICES AND FOR MAPPING ELEMENTS THEREOF

• US 20090303961A1
• Filed: 07/02/2009
• Published: 12/10/2009
• Est. Priority Date: 01/05/2007
• 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: van de Beek, Jaap, POPOVIC, Branislav, Berggren, Fredrik
• Granted Patent: US 8,311,009 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• 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
• CPC Class Codes: H04L 27/26136 Pilot sequence conveying additional information
• CPC Class Codes: H04W 48/20 Selecting an access point

Abstract

An method for, in a cellular telecommunication system, generating reference sequence matrices and for mapping elements of said reference sequence matrices to reference signal positions having predetermined locations in two-dimensional multi-carrier time-frequency symbol spaces is provided. According to the method, a matrix S_N of dimension N×N having N orthogonal rows or columns and orthogonal parts of rows or columns, respectively, N being a positive integer >3, is generated. N reference sequence matrices OS^(k), k=0, . . . , N−1, are then generated by forming rows or columns of the kth reference sequence matrix OS^(k) based on at least part of the (k+1)th row or column, respectively, of said orthogonal matrix S_N. Further, in a cell, within a given time period, mapping elements of one of said N reference sequence matrices OS^(k) to reference signal positions having predetermined locations in two-dimensional multi-carrier time-frequency symbol spaces.

Claims

1. A method in a cellular telecommunication system for generating reference sequence matrices and for mapping elements of said reference sequence matrices to reference signal positions having predetermined locations in two-dimensional multi-carrier time-frequency symbol spaces, wherein the method comprises:

generating a matrix S_N of dimension N×

N having N orthogonal rows or columns and orthogonal parts of rows or columns, respectively, N being a positive integer >

3;

generating N reference sequence matrices OS^(k), k=0, . . . , N−

1, by forming rows or columns of the kth reference sequence matrix OS^(k) based on at least part of the (k+1)th row or column, respectively, of said orthogonal matrix S_N, and

mapping elements of one of said N reference sequence matrices OS^(k) to reference signal positions having predetermined locations in two-dimensional multi-carrier time-frequency symbol spaces.

2. The method according to claim 1, wherein mapping the elements comprises:

mapping in a cell, within a given time period, elements of one of said N reference sequence matrices OS^(k) on a time-frequency symbol space of said cell by assigning elements located in vicinity of each other in each mapped reference sequence matrix OS^(k) to reference signal positions located in vicinity of each other.

3. The method according to claim 1, wherein said matrix S_N is calculated according to:

$S_N=A\otimes <br><br>B=\left(\begin{array}{ccc}{a}_{11}<br><br>B& \mathrm{\dots <br><br>}& a_{1<br><br><br><br>M}<br><br>B\\ \mathrm{⋮<br><br>}& \mathrm{\ddots <br><br>}& \mathrm{⋮<br><br>}\\ a_{M<br><br><br><br>1}<br><br>B& \mathrm{\dots <br><br>}& a_{\mathrm{MM}}<br><br>B\end{array}\right),$

wherein A is an orthogonal matrix of dimension M×

M, B is an orthogonal matrix of dimension L×

L, and denotes the Kronecker product.

4. The method according to claim 1, wherein a Node B in said system controls a number of cells, and mapping the elements comprises mapping for each of said cells controlled by said Node B one reference sequence matrix OS^(k)on a time-frequency symbol space used for that cell so that a total number of 1 to N reference sequence matrices OS^(k)are mapped.

5. The method according to claim 1, wherein a Node B in said system controls a number of cells, and mapping the elements comprises using reused reference sequence matrices, thereby mapping elements of at least one of said reference sequences matrices on time-frequency symbol spaces used in at least two cells controlled by said Node B.

6. The method according to claim 1, wherein said generated reference sequence matrices OS^(k) are arranged in subsets, and reference sequence matrices OS^(k)of each of said subsets are orthogonal so that at least parts of rows or columns, respectively, of said reference sequence matrices OS^(k)are orthogonal to each other.

7. The method according to claim 1, wherein said generated reference sequence matrices OS^(k) are arranged in subsets, and each of said subsets is associated with a cell specific information, thereby each of said subsets implicitly encoding said cell specific information when each of said subsets is chosen to be used in a cell.

8. The method according to claim 7, wherein each of said subset is associated with an antenna configuration used in the cell.

9. The method according to claim 1, wherein said two-dimensional multi-carrier time-frequency symbol spaces are organized in a lattice structure defined as:

x=m₁a₁+m₂a₂,

where m₁ and m₂ are integers and a₁ and a₂ are independent elements of a time-frequency grid.

10. The method according to claim 1, wherein said step of generating said matrix S_N includes the step of recursively generating a matrix S_2L-1 by:

$S_{2<br><br><br><br>L·<br><br>l}=\left(\begin{array}{cc}{S}_{L·<br><br>l}& S_{L·<br><br>l}\\ S_{L·<br><br>l}& -S_{L·<br><br>l}\end{array}\right),l=1,2,4<br><br><br><br>\mathrm{\dots <br><br>}<br><br>,2^{m-1},$

where S_L is a matrix B.

11. The method according to claim 10, wherein said matrix B is:

$B=\left(\begin{array}{ccc}1& 1& 1\\ 1& {\mathrm{<br><br>}}^{j<br><br><br><br>2<br><br><br><br>\mathrm{\pi <br><br>}/3}& {\mathrm{<br><br>}}^{j<br><br><br><br>4<br><br><br><br>\mathrm{\pi <br><br>}/3}\\ 1& {\mathrm{<br><br>}}^{j<br><br><br><br>4<br><br><br><br>\mathrm{\pi <br><br>}/3}& {\mathrm{<br><br>}}^{j<br><br><br><br>2<br><br><br><br>\mathrm{\pi <br><br>}/3}\end{array}\right)·<br><br>{\mathrm{<br><br>}}^{j<br><br><br><br>\mathrm{\phi <br><br>}},$

where 0≦

θ

<

2π

.

12. The method according to claim 10, wherein said matrix B is:

$B=\left(\begin{array}{cc}1& 1\\ 1& -1\end{array}\right)·<br><br>{\mathrm{<br><br>}}^{j<br><br><br><br>\mathrm{\phi <br><br>}},$

where 0≦

φ

<

2π

.

13. The method according to claim 1, wherein generating N reference sequence matrices OS^(k) comprises generating the kth reference sequence matrices OS^(k) by using cyclic shifts of the (k+1)th row or column of said orthogonal matrix S_N, or by using cyclic shifts on segments of the (k+1)th row or column of said orthogonal matrix S_N.

14. The method according to claim 13, wherein said generated reference sequence matrices OS^(k)are arranged in subsets defined by:

Ω

_k={OS<sup>3(k−

1)</sup>,OS<sup>1+3(k−

1)</sup>,OS<sup>2+3(−

1)</sup>},k=1,2,3,4,

each subset Ω

_k being associated with information relating to an antenna configuration.

15. The method according to claim 1, wherein generating N reference sequence matrices OS^(k) comprises generating the kth reference sequence matrices OS^(k)by repeating the (k+1)th row or column of said orthogonal matrix S_N.

16. The method according to claim 1, wherein mapping the elements comprises assigning elements of concatenations of reference sequence matrices OS^(k),

$\hspace{1em}$

( O 



S ( k ) …

O 



S ( k ) ⋮

⋱

⋮

O 



S ( k ) …

O 



S ( k ) ) .

17. The method according to claim 1, wherein generating N reference sequence matrices OS^(k) includes generating more than one row or more than one column of a reference sequence matrix OS^(k) by dividing one single row or a column, respectively, in said matrix S_N and assigning the divided parts to the more than one row or column in said reference sequence matrix OS^(k).

18. The method according to claim 1, wherein said a number of said N generated reference sequence matrices OS^(k)are used for identifying at least part of the cell ID in a cell search procedure.

19. A transceiver for use in a cellular telecommunication system, said transceiver being arranged for generating reference sequence matrices and for mapping elements of said reference sequence matrices to reference signal positions having predetermined locations in two-dimensional multi-carrier time-frequency symbol spaces, wherein said transceiver comprises:

means for generating a matrix S_N of dimension N×

N having N orthogonal rows or columns and orthogonal parts of rows or columns, respectively, N being a positive integer >

3;

means for generating N reference sequence matrices OS^(k), k=0, . . . , N−

1, by forming rows or columns of the kth reference sequence matrix OS^(k) based on at least part of the (k+1)th row or column, respectively, of said orthogonal matrix S_N; and

means for mapping elements of one of said N reference sequence matrices OS^(k) to reference signal positions having predetermined locations in two-dimensional multi-carrier time-frequency symbol spaces.

20. A telecommunication system, wherein said telecommunication system comprises at least one transceiver as claimed in claim 19.