Method for improving TFCI transportation performance

Abstract

Method for improving a tfci transportation performance, including the steps of (1) coding tfci information bits to be transported through each radio frame, (2) repeating a tfci code word produced by the coding for an arbitrary times, (3) applying puncturing patterns different from each other to the repeated code words produced as many as the repeated times, and puncturing the repeated code words at locations different from each other, and (4) dividing, inserting, and transporting the punctured fixed length repeated code words in each slot of the radio frame, whereby improving tfci information transportation performance, and embodying the receiver side decoder to be identical to a case when a 32 bit code word are transported perfectly.

Description

y₀, y₁, y₂, - - - y_NB-2, y_NB-1  (2).

In this instance, there is a relation between the equation (1) and the equation (2) expressed as an equation, below.
y_{((m−1)B+i)mod B}=x_i  (3),

• • where, “k mod B” denotes a remainder when ‘k’ is divided by ‘B’. When ‘B’ is 32, the ‘i’ can be a value falling between 0 to 32.]

In a first embodiment of the present invention, a location at which the repetition occurrs less in the (B, A) code word is fixed according to the following equation (4), which is the simplest embodiment done by puncturing the code words at fixed locations.
P=(j+K)mod B, (j=0, 1, - - - , P·N−1)  (4),

Third, when a code word block is formed by a combination of individual code words, locations of bits having repeated for less number of times are made to be distributed uniformly over the entire code word block by means of the puncturing.

Fourth, locations of consecutive puncturing should be far as much as possible.

For meeting the above basic principles, the locations of bits in the (B, A) code word having repeated for less number of times are fixed according to an equation (5), below.
r_i=[(B/P(P·N)·i]+K, (i=0, 1, - - - , P·N−1)  (5),

• • where, K is a constant greater than ‘0’ and [x] denotes a greatest integer not greater than x.

Accordingly, the locations of puncturing which meet the above basic principles can be expressed as equations (6), (7), (9), and (10), where P_ij denotes a puncturing location, obtained from y_pij, denoting a (j)th puncturing position in an (i)th repeated code in the code word block obtained by repeating the bits of the TFCI code words shown in the equation (2), i=0, 1, - - - , N−1, j=0, 1, - - - , P−1, and K is an integer greater than ‘0’.
P_ij=[B/P·j+B/(P·N)·i]+B·i+K  (6),

• • where, [x] denotes a greatest integer not greater than ‘x’.

If B/P and B/(P·N) in the equation (6) are integers, the equation (6) can be expressed as an equation (7), below.
P_ij=B/P·j+B/(P·N)·i+B·i+K  (7),
and, when N=2ⁿ, an equation (8) below can be obtained.
P_ij=B/P·j+B/(P·N)·R(i, n)+B·i+K  (8),

• • where, R(i, n) denotes binary ‘i’ bit reversed into decimal ‘i’ with reference to ‘n’ bit, i.e., R(4₁₀=100₂, 3)=001₂=1₁₀.

And, when P=2^P, the following equation (9) can be obtained, where, alike a case of the equation (8), R(j, p) denotes binary ‘j’ bit reversed into decimal T with reference to ‘p’ bit.
P_ij=B/P·R(j, p)+B/(P·N)·R(i, n)+B·i+K  (9).

Other than those, if expression of ‘N’ or ‘P’ as (n)th power of 2 is impossible, by selecting i, j indices in MIL(Multistage interleaving), the following equation (10) may be used for production of a puncturing pattern.
P_ij=B/P·M₁(j)+B/(P·N)·M₂(i)+B·i+K  (10),

• • where,
    • • where, [x] represents a greatest integer not greater than X, K denotes a constant greater than or equal to ‘0’, ‘I’ denotes any interger from ‘0’ to (N−1), but may be ‘0’ or (N−1) for simplification. In this case, puncturing is occurred for particular repeated codes among the four repeated codes as shown in FIGS. 11 and 12.

    A method for improving a TFCI performance transportation in accordance with a third embodiment of the present invention will be explained, taking a case as an example, when the SF is smaller than 128 and a TTI exceeds 10 ms in the first and second embodiments in repeating and transporting bits of the TFCI code word. In this instance, when a repeating number of times according to each TTI is defined by an equation 12, Pij and Pj, a puncturing position for each case when applied to equations 6˜11 with N=nTT, P=2, B=32, K=0, may be fixed. For example, when TTI is 40 ms, the related art repeated pattern is identical to a pattern in FIG. 8, and when Pij is calculated according to equations (6)˜(10) for fixing puncturing positions for the repeated pattern, and the puncturing is carried out, a pattern shown in FIG. 9 or 10 is obtained, when N=4, P=2, B=32, K=0 are applied to equations 6˜10. And, when TTI is 80 ms, identical parameters except N=8 are applied to equations (6)˜(10). In this instance too, different from the equations (6)˜(10), when a bit to be punctured in the repeated TFCI code word for meeting the aforementioned basic principles in the present invention is represented as Ypj, and an index pj of the bit to be punctured can be expressed as an equation (11). In this case, puncturing is occurred for particular repeated codes among the four repeated codes as shown in FIGS. 11 and 12.

    The following equation (12) is an equation for calcualting nTTI defined newly for calulating ‘N’.
    nTTI=TTI/10 ms  (12),

    A fourth embodiment of the present invention will be explained, when the frame trasnport mode is operative in a compressed mode on uplink and downlink. The TFCI code word is defined as an equation (13), and in the compressed mode, the number of bits available in the TFCI fields of one radio frame is defined as D and repeated bits in the TFCI code words are defined as dk.
    c₀, c₁, c c, c₃, c₄, - - - , c_m (where, m=29)  (13),

    In this instance, an intermediate parameter ‘E’ for obtaining a repeated bits d_k in an equation (15) is defined as an equation (14), below.
    E=30−1−(N_first N_TFCI)mod 30  (14),

    • • where, N_TFCI denotes the number of bits in the TFCI field in a slot, and N_first denotes the number of the first TFCI bit in the slot directly after the TG(Transmission gap).
        d_D−31=c_Emod30, d_D−32=c_(E−1)mod30, d_D−33=c_(E−2)mod30, K, d₀=c_{{E−(D−31)}mod 30}   (15).

    That is, if a length of the TFCI code word to be transported in a compressed mode is longer than a coded 30bit TFCI code word, the TFCI code word in the compressed mode is produced by repeating bits of the TFCI code word to be inserted in a slot next to slots at which TGL (Transmission Gap Length) of a frame end among the coded 30bit TFCI code word, for minimizing an influence from imperfect power control occurred during the TGL.

    In a case D>32 in the present invention, for converting the equation (15) into an equation having a subscript m=32, the parameter ‘E’ in the equation (14) may be defined as ‘L’ as in an equation (16), and the equation (15) can be converted into an equation (17).
    L=32−1−(N_first N_TFCI)mod 32  (16),
    

    When D=31 and D=32, the radio frame transports, not after repeating a portion of bits of the 30bit coded TFCI code word, but the 31bit or 32bit coded TFCI code word as it is.

    As has been explained, the method for improving a TFCI transportation performance of the present invention has the following advantatges.

    Because the present invention can embody a receiver side decoder identical to a case when a 32bit code word is transmitted perfectly, a receiver side device is not become complicate based on decoding for 16bit or 32bit code word.

    Particularly, if the spreading factor is smaller than 128, bits of the code word are repeated, different puncturing patterns are applied to each of the repeated code block unit, even if TTI exceeds 10 ms(i.e., 20 ms, 40 ms, 80 ms), a TFCI information transportation performance is improved, and the receiver side decoder can be embodied identical to a case when a 32 bit code word are transported perfectly.

    And, when the radio frame is operative, not in a standard mode, but a compressed mode, in an uplink and a downlink, the TFCI information transportation performance can be improved.

    It will be apparent to those skilled in the art that various modifications and variations can be made in the method for improving a TFCI transportation performance of the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims

1. A method for transmitting a transport format combination indicator(tfci) in a wireless communication system, comprising the steps of:

(1) coding tfci information bits into tfci code word;

(2) repeating said tfci code word for predetermined times to obtain a code word block which comprises tfci repeated code word;

(3) selecting bits from the tfci repeated code word so that the bits to be selected can be dispersed in the code word block which is obtained by repeating the bits of the tfci code word;

(4) puncturing the selected bits from the tfci repeated code word; and,

(5) transmitting the tfci repeated code word from which the selected bits have been punctured over a radio frame.

2. A method as claimed in claim 1, wherein the repetition is determined by a spreading factor or a transport time interval of the frame or a transport mode of the frame.

3. A method as claimed in claim 1, wherein the selecting is done by uniformly dispersing the bits to be selected in the fourth code word block obtained by repeatin repeating the bits of the tfci code word.

4. A method as claimed in claim 3, wherein a location of a bit at which repetition is occurred relatively less in a repeated code word bit-stream is (J+K)mod B, where K denotes a non-negative integer, B denotes a tfci code word length, P denotes a number of bits to be punctured in the tfci code word, N denotes a repeated number of the tfci code word, and j denotes an index increasing from 0 to P*(N−1).

5. A method as claimed in claim 3, wherein a location of a bit at which repetition is occurred relatively less in a repeated code word bit-stream is ri=[B/(PN)i]+K, where K denotes a positive integer, B denotes a tfci code word length, P denotes a number of bits to be punctured in the tfci code word, N denotes a repeated number of the tfci code word, i denotes an index increasing from 0 to P*(N−1), and [x] denotes a greatest integer not greater than x.

6. A method as claimed in claim 3, wherein, if B denotes a length of the tfci code word, N denotes the number of the repetition times of the tfci code word, P denotes the number of bits of the tfci code word to be punctured, k denotes a non-negative integer, and P_ij denotes an element of the repeated tfci code word to be punctured, at a (j)th posintion and an (i)th repeated code in the code word block obtained by repeatin the bits of the tfci code word, the relationship is:

P_ij=[B/Pj+B/(PN)i]+Bi+K,

wher [x] represents a greatest integer not greater than x and i=0,1, . . . , N−1, j=1,1, . . . , P−1.

7. A method as claimed in claim 3, wherein said tfci code word which is coded from tfci information bits are comprised of 32 elements.

8. A method as claimed in claim 7, wherein, when D>32, where D denotes the number of bits available in the tfci fields of one radio frame, d_k denotes repeated bits of the tfci code word, N_tfci denotes the number of hits in the tfci field in a slot, N_first denotes the number of the first tfci bit in the slot directly after the TG(Transmission gap), and L=32−1−(N_first N_tfci)mod 32, the repeated bits are denoted as d_D−33=c_Lmod32, d_D−34=c_(L−1)mod32, d_D−35=c_{(L−2)mod 32}, . . . , d₀=c_{{L−(D−33)}mod32}.

9. The method of claim 1, wherein, after the step (2), of the tfci repeated code words word produced as many as the repeated number of times, the puncturing is conducted for bits at predetermined locations for particular repeated code words.

10. The method of claim 9, wherein if ‘P’ denotes a number of punctured bits in the tfci code word, ‘N’ denotes a repeated number of times of the tfci code word, ‘k’ denotes an integer greater than ‘0’, ‘K’ denotes a positive integer, ‘I’ is an index having a value between 0˜N−1, and ‘j’ denotes an increasing index from ‘0’ to ‘(N·P−1)’, a location of a bit to be punctured Pj can be expressed as follows:

Pj=[B/(P·N)·j]+IB+K,

where [x] denotes a greatest integer not greater than ‘x’.

11. The method of claim 1, wherein the tfci code word uses a (32, 10) Reed-Muller code for tfci information bits below 10 bits.

12. The method of claim 1, wherein when the frame transport mode is a split mode, the tfci code word uses a (16, 5) Reed-Muller code for tfci information bits below bits.

13. A method of compressing a transport format combination indicator (tfci), comprising:

repeating a tfci having a first prescribed number of bits for a prescribed number of repetitions to form a tfci repeated code word;

selecting a second prescribed number of bits from at least one of the repeated tfci that form the tfci repeated code word, such that for each selected bit, a corresponding bit in each of the remaining tfci is not selected; and

removing the selected bits from the at least one tfci repeated code words word to form a compressed tfci repeated code word.

14. The method of claim 13, wherein each of the second prescribed number of bits is selected from a single one of the repeated tfci.

15. The method of claim 14, wherein each of the selected bits is selected from a final one of the repeated tfci.

16. The method of claim 14, wherein an index of the bits to be selected from the tfci is determined by summing (a) the resultant of the first prescribed number of bits in the tfci, divided by a product of the second prescribed number of hits multiplied by the prescribed number of repetitions multiplied by a counter value indicating which one of the second prescribed number of bits is being determined; plus (b) a product of a counter value indicating from which of the number of repetitions the selected bits are located multiplied by the first prescribed number of bits in the tfci; plus (c) a constant value, wherein each of the counters begins at ‘0’, and wherein the constant value can be ‘0’.

17. The method of claim 16, wherein the first prescribed number of bits is 32, the second prescribed number of bits is ‘8’, and the number of repetitions is ‘4’.

18. The method of claim 13, wherein the second prescribed number of bits is selected in equal proportions from each of the repetitions of the tfci, each equal proportion containing a third prescribed number of bits.

19. The method of claim 18, wherein a location of the bits to be selected from each of the prescribed number of repetitions of the tfci is determined by summing (a) the dividend of the first prescribed number of bits in the tfci, divided by a product of the third prescribed number of bits multiplied by a counter value indicating which of the second prescribed number of bits to be selected is being determined; plus (b) a dividend of the first prescribed number of bits in the tfci, divided by a product of the third prescribed number of bits multiplied by the prescribed number of repetitions of the tfci multiplied by a counter value indicating the repetition for which the bit is being selected; plus (c) a product of the first prescribed number of bits in the tfci multiplied by the counter value indicating the repetition for which the bit is being selected; plus (d) a constant value, wherein each of the counters begins at ‘0’, and wherein the constant value can be ‘0’.

20. The method of claim 19, wherein the first prescribed number of bits is ‘32’, the second prescribed number of bits is ‘8’, the third prescribed number of bits is ‘2’ and the number of repetitions is ‘4’.

21. The method of claim 19, wherein the first prescribed number of bits is ‘16’ and the second prescribed number of bits is ‘1’.

22. The method of claim 13, wherein the first prescribed number of bits is ‘32’, the prescribed number of repetitions is ‘4’, and the second prescribed number of bits is ‘2’.

23. The method of claim 13, wherein the transport time interval exceeds 10 ms.

24. The method of claim 13, wherein the compressed tfci is used in at least one of an uplink and a downlink.

25. A user equipment (UE) for a mobile communication system, comprising:

means for forming a transport format combination indicator (tfci) having a first prescribed number of bits to be transported through a radio frame;

means for repeating the tfci for a prescribed number of repetitions to form a tfci repeated code word;

means for selecting a second prescribed number of bits from at least one of the repeated tfci that form the tfci repeated code word, such that for each selected bit, a corresponding bit in each of the remaining tfci is not selected;

means for removing the selected bits from the tfci repeated code word to form a punctured tfci repeated code word; and

means for forming the compressed tfci repeated code word into the radio frame to be transported.

26. The UE of claim 25, further comprising means for receiving a radio frame having a compressed tfci repeated code word and means for extracting the tfci from the compressed tfci repeated code word.

27. The UE of claim 25, wherein the means for selecting the second prescribed number of bits selects each of the second prescribed number of bits from a single one of the repeated tfci, and wherein a location of the bits to be selected from the tfci is determined by summing (a) the resultant of the first prescribed number of bits in the tfci, divided by a product of the second prescribed number of bits multiplied by the prescribed number of repetitions multiplied by a counter value indicating which one of the second prescribed number of bits is being determined; plus (b) a product of a counter value indicating from which of the number of repetitions the selected bits are located multiplied by the first prescribed number of bits in the tfci; plus (c) a constant value, wherein each of the counters begins at 0, and wherein the constant value can be 0.

28. The UE of claim 27, wherein the means for selecting the second prescribed number of bits selects the bits in equal proportions from each of the repetitions of the tfci, each proportion being a third prescribed number of bits in size.

29. The method of claim 28, the means for selecting the second prescribed number of bits identifies a location of each bit to be selected from each of the prescribed number of repetitions of the tfci by summing (a) the dividend of the first prescribed number of bits in the tfci, divided by a product of the third prescribed number of bits multiplied by a counter value indicating which of the second prescribed number of bits to be selected is being determined; plus (b) a dividend of the first prescribed number of bits in the tfci, divided by a product of the third prescribed number of bits multiplied by the prescribed number of repetitions of the tfci multiplied by a counter value indicating the repetition for which the bit is being selected; plus (c) a product of the first prescribed number of bits in the tfci multiplied by the counter value indicating the repetition for which the bit is being selected; plus (d) a constant value, wherein each of the counters begins at ‘0’, and wherein the constant value can be ‘0’.