Method for generating and allocating code pairs of orthogonal spreading codes

• US 7,099,371 B2
• Filed: 12/28/2001
• Issued: 08/29/2006
• Est. Priority Date: 12/29/2000
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Roh, Dong Wook
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): Pathak, Sudhanshu C.
• Application Number:
  US10/029,278
• Publication Number:
  US 20030185281A1
• Time in Patent Office: 1,705 Days
• Field of Search: 375/140, 375/130, 375/138, 375/144, 375/149, 375/316, 375/343, 370/503, 370/208, 370/335, 370/347, 370/201
• US Class Current: 375/140
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70706 with means for reducing the peak-to-average power ratio
• CPC Class Codes: H04J 13/004 Orthogonal
• CPC Class Codes: H04J 13/007 LAS, i.e. LA, LS and LAS codes
• CPC Class Codes: H04J 13/14 Generation of codes with a zero correlation zone
• CPC Class Codes: H04J 13/22 Allocation of codes with a zero correlation zone

Abstract

The present invention relates to an orthogonal spreading code in a code division multiple access (CDMA) mobile communication system, and more particularly, to a method for generating and allocating code or code pairs on the basis of an orthogonal code set, which is generated using orthogonal spreading codes, so as to reduce a peak-to-average power ratio and enlarge the length of an interference free window. In accordance with the invention, at least one orthogonal code set is generated based upon orthogonal spreading codes, one of the at least one orthogonal code set is determined as a representative orthogonal code set, and then the order is allocated according to rules determined based upon the representative orthogonal code set. The codes or code pairs are generated and allocated using the orthogonal spreading codes, so as to reduce a Peak-to-Average Power Ratio or extend the length of an interference free window (IFW).

Claims

1. A method for allocating code pairs of orthogonal spreading codes having guard bits of 0, comprising:

generating at least one orthogonal code set based upon the orthogonal spreading codes;

determining one of the at least one orthogonal code set as a representative orthogonal code set; and

allocating an order of code pairs according to a prescribed rule based upon the representative orthogonal code set.

2. The method according to claim 1, further comprising matching the orthogonal spreading codes to at least one element included in the representative orthogonal code set in an ascending order if the representative orthogonal code set is determined.

3. The method according to claim 1, wherein said step of generating the orthogonal code set comprises:

generating the orthogonal spreading codes corresponding to a selected code length;

adjusting the interval of an Interference Free Window (IFW) length based upon a selected code component length; and

generating the at least one orthogonal code set and at least one element included in each of the at least one orthogonal code set until a prescribed condition is satisfied.

4. The method according to claim 3, wherein the prescribed condition comprises 2^g−

1≦

L_IFW≦

2^g

wherein;

L_IFW is the length of the interference free window

g is a natural number.

5. The method according to claim 3, wherein the at least one orthogonal code set is calculated using:

$O_K=\left\{{\mathrm{LS}}_{\left(k-1\right)\times <br><br>2^{m-g}}^{N+2\times <br><br>L_{\mathrm{GUARD}}},{\mathrm{LS}}_{\left(k-1\right)\times <br><br>2^{m-g}-1}^{N+2\times <br><br>L_{\mathrm{GUARD}}},\mathrm{\dots <br><br>}<br><br>,{\mathrm{LS}}_{\left(k-1\right)\times <br><br>2^{m-g}-2^{m-g}-1}^{N+2\times <br><br>L_{\mathrm{GUARD}}}\right\},$

wherein O_k is the kth orthogonal code set, and

${\mathrm{LS}}_{\left(k-1\right)\times <br><br>2^{m-g}+j}^{N+2\times <br><br>L_{\mathrm{GUARD}}}$

is the jth orthogonal spreading code of the kth orthogonal code set;

wherein;

L_GUARD is the length of guard component

g &

m are natural number(s)

K is an integer

N is the code length.

6. The method according to claim 1, further comprising:

determining whether to differently allocate the orthogonal spreading codes corresponding to the at least one element of the representative code set to an I branch and a Q branch; and

determining whether to allocate code pairs which minimize a peak-to-average power ratio if differently allocated.

7. The method according to claim 6, further comprising:

generating at least one code set using the representative code set if the orthogonal spreading codes are not differently allocated to the I branch and the Q branch;

selecting the at least one code set in a prescribed order; and

allocating the order of the codes according to a prescribed rule based upon at least one element of the selected code set.

8. The method according to claim 7, wherein the at least one code set is calculated using:

L_k={l_2k,l_2k+1,l_2k+2, . . . , l<sub>2k+1−

2</sub>,l<sub>2k+1−

1</sub>},

wherein L_k is the kth code set, and l is an element included in the code set;

wherein further;

k is an integer.

9. The method according to claim 6, further comprising:

generating at least one code pair based upon the representative code set if the code pair is allocated to minimize the peak-to-average power ratio;

generating a code pair set based upon the at least one code pair; and

allocating the code order based upon the at least one code pair included in the code pair set.

10. The method according to claim 9, wherein the code pair is generated on the basis of a center of the at least one element of the representative code set, and wherein the at least one element is arrayed in the ascending order.

11. The method according to claim 6, further comprising:

grouping at least one code pair set according to a prescribed rule based upon the representative code set if the code pair which minimizes the peak-to-average power ratio is not allocated;

selecting a code pair set from the at least one code pair set according to the determined order;

generating at least one code pair on the basis of the center of the at least one element included in the selected code pair set; and

allocating the code order based upon the at least one code pair.

17. The method of claim 1, wherein allocating the order of code pairs comprises:

arraying the elements of the orthogonal code set in an ascending order, wherein the ascending order comprises a first element, a center element, an element before center and a last element;

pairing the first element with the center element; and

pairing the element before center with the last element.

18. The method of claim 1, wherein allocating the order of code pairs comprises allocating code pairs in accordance with:

P={(l₀,l<sub>2m−

g−

1</sub>),(l₁,l<sub>2m−

g−

1+1</sub>), . . . , (l<sub>2m−

g−

1−

1</sub>,l<sub>2m−

g−

1</sub>)

wherein l_j is an orthogonal code from the orthogonal code set, “

g”

is a natural number, and “

m”

is a natural number greater than 2.

19. The method of claim 1, wherein allocating the order of code pairs comprises:

arraying the elements of the orthogonal code set in an ascending order, wherein the ascending order comprises a first half of elements with a first element, a quarter-center element in the center of the first half of elements, and a last element;

pairing the first element with the first element from the quarter-center element; and

pairing the element before the quarter-center with the last element.

20. The method of claim 1, wherein allocating the order of code pairs comprises allocating code pairs in accordance with:

L<sub>m−

g−

1</sub>={l<sub>2m−

g−

1</sub>,l<sub>2m−

g−

1+1</sub>,l<sub>2m−

g−

1+2</sub>, . . . , l<sub>2m−

g−

2</sub>,l<sub>2m−

g−

1</sub>}

wherein a representative orthogonal code set is expressed as;

L_i={l₀,l₁,. . . ,l<sub>2m−

g−

2</sub>,l<sub>2m−

g−

1</sub>}

wherein “

m” and

“

g”

are natural numbers.

12. A method for generating an orthogonal code set using orthogonal spreading codes, comprising:

generating orthogonal spreading codes corresponding to a prescribed code length;

adjusting an interval of a length of an interference free window (IFW) based upon a prescribed code component length; and

generating at least one orthogonal code set based upon the orthogonal spreading code if the length of the IFW interval is adjusted.

13. The method according to claim 12, wherein the at least one orthogonal code set is generated until a prescribed condition is satisfied.

14. A method for allocating code pairs using orthogonal spreading codes, comprising:

determining one of at least one orthogonal code set as a representative orthogonal code set;

allocating different orthogonal spreading codes to an I branch and a Q branch, and determining whether to minimize a peak-to-average power ratio;

generating at least one code pair based upon the representative orthogonal code set according to whether the code pair for minimizing a peak-to-average power ratio is allocated;

generating a code pair set based upon the at least one code pair; and

allocating a code order based upon the at least one code pair included in the code pair set, wherein the code pair is generated on the basis of a center of at least one element of the representative orthogonal code set, wherein the at least one element is arrayed in an ascending order.

15. A method for allocating code pairs using orthogonal spreading codes, comprising:

determining one of at least one orthogonal code set as a representative orthogonal code set;

allocating different orthogonal spreading codes to an I branch and a Q branch, and determining whether to minimize a peak-to-average power ratio;

grouping at least one code pair set according to a prescribed rule based upon the representative orthogonal code set in accordance with whether the code pair for minimizing a peak-to-average power ratio is allocated;

selecting a code pair set from the at least one code pair according to a prescribed order;

generating at least one code pair based on a center of at least one element of the representative orthogonal code set and at least one element included in the selected code pair set; and

allocating a code order based upon the at least one code pair.

16. A method for allocating code pairs using orthogonal spreading codes, comprising:

determining one orthogonal set of at least one orthogonal code set as a representative orthogonal code set;

determining whether to identically allocate the same orthogonal spreading code to an I branch and a Q branch;

generating at least one code set by using the orthogonal code set according to whether different orthogonal spreading codes are to be allocated to an I component and a Q component;

selecting the at least one code set in a prescribed order; and

allocating a code order according to a prescribed rule based upon at least one element of the selected code set, wherein the at least one element is arrayed in an ascending order.

21. A method to generate orthogonal code sets, comprising:

selecting a code length N equal to or larger than 4;

determining whether the selected code length N equals 2^m, where m is equal to or larger than 2;

generating an orthogonal spreading code if N equals 2^m;

selecting a code component length L_GUARD and an IFW length L_IFW;

determining whether L_GUARD≧

L_IFW≧

0 is true;

selecting a new L_GUARD and L_IFW until L_GUARD≧

L_IFW≧

0 is true;

calculating g based on 2<sup>g−

1</sup>≦

L_IFW≦

2^g if L_GUARD≧

L_IFW≧

0;

setting k equal to 1, and j equal to 0;

repeat adding the (k−

1)2<sup>m−

g</sup>+j orthogonal spreading code to the k^th orthogonal code set and adding 1 to j until j >

2<sup>m−

g</sup>−

1 is true;

adding 1 to k if j>

2<sup>m−

g</sup>−

1 is true;

if k>

2^g is not true, repeat adding the (k−

1)2<sup>m−

g</sup>+j orthogonal spreading code to the k^th orthogonal code set and adding 1 to k until k>

2^g is true; and

selecting one orthogonal code set from the generated orthogonal code sets as the representative orthogonal code set if k>

2^g is true;

wherein;

“

m” and

“

g”

are natural numbers

“

k” and

“

j”

are integers

L_GUARD is the length of guard component

L_IFW is the length of the interference free window.

22. A method of allocating code pairs using a representative orthogonal code set, comprising:

determining whether orthogonal spreading codes are to be differently allocated to an I branch and a Q branch or to be similarly allocated to the I branch and the Q branch;

if orthogonal spreading codes are to be differently allocated, determining whether code pairs to minimize peak-to-average power ratio are to be allocated;

if orthogonal spreading codes are to be differently allocated to an I branch and a Q branch, and are to be allocated to minimize peak-to-average power ratio, allocate orthogonal spreading codes by;

arraying the elements of the orthogonal code set in an ascending order, wherein the ascending order comprises a first element, a center element, an element before center and a last element,

pairing the first element with the center element, and

pairing the element before center with the last element;

if orthogonal spreading codes are to be differently allocated to an I branch and a Q branch and are not to be allocated to minimize peak-to-average power ratio, allocate orthogonal spreading codes by;

arraying the elements of the orthogonal code set in an ascending order, wherein the ascending order comprises a first half of elements with a first element, a quarter-center element in the center of the first half of elements, and a last element,

pairing the first element with the first element from the quarter-center element, and

pairing the element before the quarter-center with the last element;

if the orthogonal spreading codes are to be similarly allocated to the I branch and the Q branch allocate orthogonal spreading codes by allocating code pairs in accordance with;

L={l₀,l₁, . . . ,l<sub>2m−

g−

2</sub>,l<sub>2m−

g−

1</sub>}

wherein a representative orthogonal code set is expressed as;

P={(l₀,l<sub>2m−

g−

1</sub>),(l₁,l<sub>2m−

g−

1+1</sub>), . . . ,(l<sub>2m−

g−

1−

1</sub>,l<sub>2m−

g−

1</sub>)

wherein “

m” and

“

g”

are natural numbers.

23. The method of claim 22, wherein if orthogonal spreading codes are to be differently allocated to an I branch and a Q branch and are to be allocated to minimize peak-to-average power ratio, allocating code pairs in accordance with:

L<sub>m−

g−

1</sub>={l<sub>2m−

g−

1</sub>,l<sub>2m−

g−

1+1</sub>,l<sub>2m−

g−

1+2</sub>, . . . ,l<sub>2m−

g−

2</sub>,l<sub>2m−

g−

1</sub>}

wherein “

l”

is an orthogonal code from the orthogonal code set, “

g”

is a natural number, and “

m”

is a natural number greater than 2.

24. An apparatus for generating orthogonal spreading codes, comprising:

a processor coupled to a memory, wherein the processor and the memory are configured to;

select a code length N equal to or larger than 4;

determine whether the selected code length N equals 2^m, where m is equal to or larger than 2;

generate an orthogonal spreading code if N equals 2^m;

select a code component length L_GUARD and an IFW length L_IFW;

determine whether L_GUARD≧

L_IFW0 is true;

select a new L_GUARD and L_IFW until L<sub>GUARD≧

LIFW</sub>≧

0 is true;

calculate g based on 2<sup>g−

1</sup>≦

L_IFW≦

2^g if L_GUARD≧

L_IFW≧

0;

set k equal to 1, and j equal to 0;

repeat adding the (k−

1)2<sup>m−

g</sup>+j orthogonal spreading code to the k^th orthogonal code set and adding 1 to j until j>

2<sup>m−

g</sup> is true;

add 1 to k if j>

2<sup>m−

g</sup>−

1 is true;

if k>

2^g is not true, repeat adding the (k−

1)2<sup>m−

g</sup>+j orthogonal spreading code to the k^th orthogonal code set and add 1 to k until k>

2^g is true; and

select one orthogonal code set from the generated orthogonal code sets as the representative orthogonal code set if k>

2^g is true

wherein;

“

m” and

“

g”

are natural numbers

“

k” and

“

j”

are integers

L_GUARD is the length of guard component

L_IFW is the length of the interference free window.

25. An apparatus for allocating orthogonal spreading codes using a representative orthogonal code set, comprising:

a processor coupled to a memory, wherein the processor and the memory are configured to;

determine whether orthogonal spreading codes are to be differently allocated to an I branch and a Q branch or to be similarly allocated to the I branch and the Q branch;

if orthogonal spreading codes are to be differently allocated, determine whether code pairs to minimize peak-to-average power ratio are to be allocated;

if orthogonal spreading codes are to be differently allocated to an I branch and a Q branch, and are to be allocated to minimize peak-to-average power ratio;

array the elements of the orthogonal code set in an ascending order, wherein the ascending order comprises a first element, a center element, an element before center and a last element,

pair the first element with the center element, and

pair the element before center with the last element;

if orthogonal spreading codes are to be differently allocated to an I branch and a Q branch and are not to be allocated to minimize peak-to-average power ratio;

array the elements of the orthogonal code set in an ascending order, wherein the ascending order comprises a first half of elements with a first element, a quarter-center element in the center of the fast half of elements, and a last element,

pair the first element with the first element from the quarter-center element, and

pair the element before the quarter-center with the last element;

if the orthogonal spreading codes are to be similarly allocated to the I branch and the Q branch, allocate orthogonal spreading codes in accordance with;

L={l₀,l₁, . . . ,l<sub>2m−

g−

2</sub>,l<sub>2m−

g−

1</sub>}

wherein a representative orthogonal code set is expressed as;

L<sub>m−

g−

1</sub>={l<sub>2m−

g−

1</sub>,l<sub>2m−

g−

1+1</sub>,l<sub>2m−

g−

1+2</sub>, . . . ,l<sub>2m−

g−

2</sub>,l<sub>2m−

g−

1</sub>}

wherein “

m” and

“

g”

are natural numbers.