KR100293475B1 - Method for phase offset caculation of binary code - Google Patents

Abstract

PURPOSE: A method for calculating a phase offset of a binary code is provided to calculate the phase offset of the binary code in a subscriber terminal by simply calculating the phase offset of the binary code. CONSTITUTION: If a binary code having elements is received(S11), a weight value of an accumulation function is set(S12). A weight accumulation value is calculated through a weight value calculating circuit(S13). An inverse element is calculated using a phase converting circuit and the calculated inverse element is multiplied with the weight accumulation value(S14). A modulo n operation is performed using a modulo operating circuit(S15), and a phase offset of the binary code is calculated(S16).

Description

Phase offset calculation method of binary code {Method for phase offset caculation of binary code}

The present invention relates to a method for calculating a phase offset of a binary code for use in a mobile communication system.

In general, a binary code of q = 2 is used among codes having a q element for information transmission in digital communication used in a CDMA system or a CTDMA system.

Analog signals such as audio and video become binary codes through analog-to-digital conversion, and these binary codes are transmitted over the air or wired through a frequency translation process called modulation. Restores to analog signal again.

As described above, the binary code is not only transmitted in an information manner but also used as a spread code in a code division multiple access (CDMA) scheme and a code time division multiple access (CTDMA) scheme of mobile communication. .

Due to the necessity of increasing capacity in cellular mobile communication, in Europe, Digital Cellular Mobile Communication has been commercialized by adopting GSM (Global System for Mobil Communication) as Time Division Multiple Access (TDMA) method, and in the US, it has been commercialized by adopting TDMA method and CDMA method. In Korea, T1A / ELA / IS95CDMA developed by Qualcomm in the United States is adopted as a mobile communication standard and commercialized.

In the CDMA system employed in the above schemes, a code having a specific characteristic of a code autocorrelation function is used as a spread code and used for error correction, error detection, synchronization of a receiver, and encryption.

In the CDMA system, different base offsets are assigned to each base station, and each base station is distinguished using the allocated phase offset, thereby soft handoff of matching a phase offset of a pseudo noise (PN) code between each base station. (soft handoff) is possible, and a mobile station belonging to one cell classifies signals received from different base stations using the phase difference of the same PN code.

In the CDMA system according to the prior art, each received PN spreading code is generally one-to-one corresponded to a reference PN spreading code having a length of 2 to ¹⁵ bits, and a phase offset information of the PN spreading code for distinguishing each base station is obtained. Since the calculation amount is very large and the hardware required for this is complicated, it is practically impossible to calculate the phase offset information of the PN spreading code at each terminal (or mobile station), so that each base station calculates the phase offset of the PN spreading code. After that, it is loaded on a transmission signal and sent to each terminal.

In the CTDMA system proposed for the International Telecommunication Standardization Sector (ITSS), a Barker code having a length of 13 is used as a spreading code and different phase offsets or times are applied to multiple subscribers using the same bandwidth of one base station. Although the same Barker spreading code having an offset is allocated, that is, the phase offset information becomes the channel number assigned to each subscriber, the subscribers are classified, but the CTDMA system transmits the offset information from the base station for the same reason as in the above-described CDMA system. It is used to load it to the terminal.

Therefore, in the above-described mobile communication method used in the CDMA system, the mobile station (or terminal) cannot obtain phase offset information without providing the phase offset information for the neighboring cell from the base station. It is not only possible to demodulate the signal received by the base station belonging to it and the signal received by the other base station at the same time. In addition, when one mobile station (terminal) moves out of the area of the base station to which it belongs, it moves to another base station having a different phase offset. Since the phase offset of the base station to which the base station belongs is not matched with the phase offset of the spreading code used by another base station, the mobile station cannot have its own handoff function, which increases the work load of the base station and uses the CTDMA system. Even if you do Particles cannot obtain the phase offset information used by other subscribers themselves without the help of the base station, and because the subscriber cannot determine and use the phase offset or channel that is not used by other subscribers in the communication base station, the base station will be overloaded. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a method for calculating a phase offset of a binary code, which enables a user to easily calculate a phase offset of a binary code since the phase offset of the binary code can be easily calculated. have.

1 is a block diagram for implementing a method for calculating a phase offset of a binary code of the present invention;

2 is a detailed block diagram of the weighted accumulation value calculating circuit of FIG. 1;

3 is a block diagram for implementing another method of calculating a phase offset of another binary code according to the present invention;

4A is a flow chart for implementing a first embodiment of the present invention;

4b is a flow chart for implementing a second embodiment of the present invention;

5 is a flowchart for implementing a third embodiment of the present invention;

6A to 6F show the phase offset calculation values according to the first embodiment,

7A to 7F are diagrams illustrating a phase offset calculation value according to the second embodiment;

FIG. 8 is a diagram showing an accumulation function value according to a weight change and a circulation of a binary code in a third embodiment.

Explanation of symbols for main parts of the drawings

10: weighted accumulation value calculating circuit 11, 15: adder

12: 1 bit delay 13: Accumulator

14 weighting unit calculating unit 16 switching unit

20: phase shifter 30: modulo operation unit

40, 41: phase shift weighted accumulation value calculation circuit

42, 43: adder 44: modulo operation circuit

The method for calculating a phase offset of a binary code according to the present invention for achieving the object of the present invention comprises the steps of receiving a binary code T ⁱ (C) circulating in a period n, and after setting the accumulation function weight of the binary code, Calculating a binary code weighted accumulated value by applying the weight to the binary code, phase shifting the binary code weighted accumulated value, and performing a modulo operation on the weighted accumulated value of the phase shifted value by modulating the binary code. Calculating a phase offset.

In another aspect of the present invention, a method for calculating a binary code phase offset includes receiving the same binary code T ^x (C) and T ^Y (C) having a period n and having different phase offsets X and Y; Calculating weighted accumulation values A ^S (T ^X (C)) and A ^l (T ^Y (C)) of two different binary codes using the cumulative accumulation weights of s and l, respectively; If the element is ^{{-1, 1}, α *} (nk) ≡1 (modn) the algebraic inverse α ^* set up, and if ^{{0,1} α * (nk)} ≡1 (modn) the algebraic inverse α ^* And phase shifting the two weighted accumulation values A ^S (T ^X (C)) and A ^l (T ^Y (C)) using the algebraic inverse α ^* and then converting the difference α ^* A ^S ( T ^x (C))-α ^* A ^l (T ^Y (C)) to calculate and obtain, and the α ^* A ^S (T ^X (C))-α ^* A ^l (T ^Y (C)) Add the difference lS of the weights, and then calculate the result of module n to output the phase offset XY of the two binary codes. It is characterized by the yirueojim including the steps:

Before describing an embodiment of the present invention, terms used in the present invention are defined.

If the binary code C is n, and k is the number of elements "0" or "-1" contained in the binary code, n is a binary code consisting of two elements "0" and "1". A binary sign that satisfies the condition that and k are small, that is, gcd (n, k) = 1 (where gcd (n, k) represents the greatest common divisor of integers n and k), or "-1 In the case of two elements "and" 1 ", n and 2k are binary codes that satisfy the preconditioning condition, that is, gcd (n, 2k) = 1.

The code C and the right traversal operator T of an n-tuple sequence (a set formed of n elements) are defined as in Equation 1 below.

↓

↓

And i ≡ j (mod n),

The relationship is established. Where i, j is an integer, T ⁰ C = C = (C ₀ , C ₁ , ??, ??, C _n-2 , C _n-1 ), and C ₀ , C ₁ ,. , C _n-2 and C _n-1 are elements.

Further, the sign T ^j (C) is defined by the polynomial C (x) as in Equation 2.

C (x) = C _nj + C _{n-j + 1} χ +... + C _nj-1 x ^n-1

An accumulation function having a weight of l is defined as in Equation 3.

x ^l C (x) ?? _{x = 1}

= lC _nj + (l + 1) C _{n-j + 1} +... … + (l + n-1) C _nj-1

Where l is an arbitrary integer, and if two integers l and s satisfy the condition of l ≡s (modn), then A ^l (T ^j (C)) ≡ A ^S (T ^j (C)) (modn) The joint formula holds.

The accumulation function A ^l (C) is denoted by A ^l ₁ (C) when the element of the n-group binary code C is {-1, 1}, and A ^l ₀ (C) when the element is {0,1}. In the case of A ^l (C) without the subscript, the element of the binary code C may belong to any of the two sets.

In addition, if the binary code C satisfies the condition of A ^l (T ^j (C)) n 0 (modn), it is defined as a reference code or zero offset code of an accumulation function having a weight of l. do.

And, if the binary code C is composed of elements of {0,1}, α ^* is set as the algebraic inverse of nk for modulo n, where α ^* (nk) = 1 (modn).

Further, if the binary code C consists of elements of {-1,1}, α ^* is set as the algebraic inverse of n-2k to modulo n with α ^* (n-2k) = 1 (modn). .

In the case where the weight l is 1 from Equation 3, Equation 4 is obtained.

X ^l C (X) ?? _{X = 1}

= (xC _nj + x ² C _{n-j + 1} ?? + x ^n-1 C _ni-2 + X ⁿ C _nj-1 ) ?? _{x = 1}

= C _nj + 2C _{n-j + 1} + ?? + (n-1) C _nj-2 + nC _nj-1

= C _nj-1

+ (C _nj-1 + C _nj-2 )

??

+ (C _nj-1 + C _nj-2 + ?? + C _{n-j + 1} )

+ (C _nj-1 + C _nj-2 + ?? + C _{n-j + 1} + C _nj )

Then, equation (5) is derived from equations (3) and (4).

A ^l (T ^j (C)) = C _nj + 2C _{n-j + 1} + ?? + nC _{n-j + 1} + (l-1) (C _nj + C _{n-j + 1} + ?? + C _nj-1 )

= A ^l (T ^j (C)) + (l-1) C (1)

Hereinafter, embodiments of the present invention will be described based on the terms and the accompanying drawings defined in this way.

First embodiment.

In the first embodiment, the binary code satisfying the condition of gcd (n, k) = 1, that is, the elements of the binary code are "0" and "1", and the number of "0" contained in the period n and the binary code is k. When n and k calculate the phase offset of binary code C satisfying the sweep condition, Fig. 1 shows a phase offset calculation circuit of binary code using an accumulation function having a weight of l for implementing the present embodiment. FIG. 2 is a block diagram illustrating the weighted accumulation value calculating circuit 10 of FIG. 1 in detail. FIG. 3 is a flowchart illustrating a binary code phase offset calculation method of the present invention.

First, when T ⁱ (C) is received and input to a binary unit having a period of n and an element of {0, -1} in S11 (S11), the weight l of the accumulation function is set in S12.

In operation S13, a weighted accumulated value A ¹ (T ⁱ (C)) is calculated.

The weight accumulation value calculation is performed through the weight accumulation value calculation circuit 10 shown in FIG.

That is, first, the first bit C _ni-1 of the binary code T ⁱ (C) is added to the adder 11 at time T = Tb (in this case, the value input through the 1-bit delay unit 12 is added). Since it is zero, the first bit _Cni-1 is outputted and inputted to the accumulator 13, and at the same time, the 1-bit delay 12 is delayed by 1 bit.

Next, when T = 2Tb, the newly input second bit C _ni-2 of the _{binary code} is input at the previous T = Tb, and is added to the first bit value C _ni-1 delayed by one bit in the adder 11 to accumulate ( At the same time as input to 13) and delayed again through the 1-bit delay unit 12.

At this time, the accumulated value of the accumulator 13 is the accumulator for the _{(C ni-1 + C ni} -2) input from the C _ni-1 and T = 2Tb input at T = Tb accumulated value C _ni-1 + ( C _ni-1 + C _ni-2 ).

In this manner, when the last bit (nj) is input to the adder 11 at T = nTb, it is output from the adder 11 at T = (n-1) Tb and then delayed and output from the 1-bit delay unit 12. to the _{C ni-1 + C ni-} 2 + ?? + C ni + C _ni is added to the _first value output by the _{C ni-1 + C ni-} 2 + ?? + C ni-1 + C ni The accumulator 13 is inputted to the accumulator 13 to calculate the accumulated value represented by Equation 4, and is inputted to the weight calculation circuit 14 to weight (l-1) (C _{n -i +} ?? + C _ni-2 + C _{ni. −1} ) = (l-1) C (1) is calculated.

In this case, the outputs of the accumulator 13 and the weight calculation circuit 14 of T = nTb are added by the adder 15 to calculate a weighted accumulation value A ^l (T ⁱ (C)) represented by Equation 5, and switching is performed. It outputs through the part 16.

Then, in step S14, the inverse α ^* with α ^* (nk) = 1 (modn) is calculated using the phase shift circuit 20 and multiplied by the weighted accumulation value A ^l (T ⁱ (C)) (S14). Modulo n operation is performed using the furnace calculation circuit 30 to calculate the phase offset of the binary code.

6 (a) to 6 (f) show the binary code T ⁱ (C) when the number of elements of "0" is 1 to 6, that is, k = 1 to 6 when the period n = 7, the weight l = 1; Weighted cumulative value of (T ⁱ (C)) and the phase offset calculated α ^* (T ⁱ (C)) (modn), where n = 7 and k = 1, as shown in Fig. 6 (a), α ^* is expressed in the relation of α ^* (nk) = 1 (modn). substituting n = n and K = 1 it can be seen that ^{α * (7-1) = 1 (} modn) , and thus α ^* 6 = α ^* = 6 from 1 (modn).

Therefore, the phase offset calculated value α ^* (T ⁱ (C)) (modn) is 6 A value for each i is obtained as (T ⁱ (C)) (mod n) as shown in FIG. 6 (a).

When the phase offset of a binary code is calculated also in the case of k = 2-6 by such a method, it is as showing to FIG.6 (b)-FIG.6 (f). As can be seen from Figs. 6 (a) to 6 (f), it can be seen that the i value and the phase offset value are the same in all cases.

Second embodiment.

The second embodiment calculates the phase shift value when the elements of the binary code are " -1 " and " 1 ". In the first embodiment, the inverse a is a relation of α ^* (nk) = 1 (modn). The second embodiment is identical to the first and second embodiments except that the inverse α ^* is obtained using a relational expression of α ^* (n-2k) = 1 (modn).

That is, the first embodiment, Fig 4 (a) α ^* · to produce a phase shift value in step S14 of the (nk) ≡1 (modn) an inverse α ^* was calculated, weighted accumulated value obtained in step S13 Although A ^l (T ^j (C)) is multiplied by the inverse α ^* , in the second embodiment, the relation of α ^* (n-2k) ≡ 1 (modn) in step S'14 of FIG. Except for calculating α ^* by using the same procedure as in the first embodiment, the same reference numerals are used for the same process and detailed description thereof will be omitted.

In the second embodiment, the weighted accumulation value A ^l (T ⁱ (C)) obtained in step S13 is obtained by obtaining the inverse α ^* using the relational expression of α ^* · (n-2k) ≡1 (modn) in step S'14. After multiplying by, using the modulo n arithmetic circuit 30 of FIG. 1, this result is subjected to a module operation to output a phase offset calculation value of a binary code (S15, S16).

For example, when n = 7 and k = 1, the inverse α ^* is substituted for α ^* (n-2k) ≡1 (modn) by replacing n = 7, k = 1 to α5 ≡1 (mod7n). If we calculate and modulate from this, we can see that α ^* = 3.

Thus, when n = 7 and the weight l is 1, the weighted accumulated value and the weighted accumulated value are calculated by modulating the weighted accumulated value and the phase offset value is calculated as shown in Figs. 7 (a) to 7 ( same as f).

Third embodiment.

3 is a block diagram of a circuit for implementing the method of the third embodiment of the present invention, and FIG. 5 is a flowchart showing a method for implementing the method of the third embodiment.

The third embodiment satisfies the condition that gcd (n, 2k) = 1 when the element of the binary code consists of {-1, 1}, and gcd () when the element of the binary code consists of {0, 1}. n, k) = 1 for a binary code that satisfies the condition, a phase offset between codes inputted through different paths using an accumulation function having a different weight, and the period is n in step S21. The weights l and s of the accumulation function for the same binary code T ^X (C) and T ^Y (C) having phase offsets X and Y, respectively, are set.

In S23, the weighted accumulated values A ^S (T ^X (C)) and A ¹ (T ^Y (C)) are calculated using the set weights l and s.

Next, in S24, if the element of the binary code is {-1, 1}, the inverse α ^* which is α ^* (n-2k) ≡ 1 (modn) is set, and if {0, 1}, α ^* (nk) ≡ After setting the inverse α ^* which is 1 (modn), the weighted accumulation values A ^S (T ^X (C)) and A ¹ (T ^Y (C)) are calculated from the inverse α α ^* .

Then, if the elements of binary code {1, 1} In step ^{S24, α * (n-2k)} ≡1 (modn) of α ^* set value and, if the {0,1} α ^* (nk) After setting α ^* which is ≡1 (modn), multiply the value α ^* by the weighted accumulated values A ^S (T ^X (C)) and A ^l (T ^Y (C)), respectively, to obtain α ^* A ^S (T ^X ( C)) and α ^{* Al} (T ^Y (C)).

The steps S22 and S24 are performed by the phase shift weighted accumulation value calculating circuits 40 and 41 of FIG. 3, respectively.

Next, α ^* A ^S (T ^X (C))-α ^* A ^l (T ^Y (C)) is calculated in step S25. This S25 step is performed by the adder 42 of FIG.

Next, in step S26, the weight difference ls is added to the result value calculated using the adder 42 of FIG. 3, and in step S26, the modulo operation is performed using the modulo n operation circuit 44, and then S28. In step 2, the phase offsets XY of the two binary codes are output.

The phase offset XY of the two binary codes calculated above means that the code T ^X (C) is XY bit traversed to the right from the code T ^Y (C).

For the third embodiment, the period n is 5, k is 3, and the binary code is C = (0.0.0.1.1.1), X = 3, Y = 20, S = 2, l = 3 The phase offset between two binary codes when set is as follows.

Therefore, using the above values, the phase offset between two binary codes is α ^* A ^S (T ^X (C)) = α ^* (T ³ (C)), α ^* A ^l (T ^Y (C)) = α ^* (T ³ (C)), ls = 3-2 = 1.

Since n = 5 and k = 3, gcd (n, k) = 1.

And since the algebraic inverse α ^* = 3 of a = -3 to modulo 5, the table shown in FIG. 8 can be obtained. The value of each column in FIG. 8 represents a change in the accumulation function value as the binary code circulates when the weight is determined, and it can be seen that it is a complete surplus system with respect to modulo 5.

In addition, the value of each term of FIG. 8 represents the change of the accumulation function value according to the change of the weight, and it can be seen that this method is also a full surplus system.

Therefore, α ^* from the table of FIG. (T ³ (C)) (mod 5) ≡1, α ^* (C) (mod5) ≡4.

Thus, the output of the adder 42 of FIG. 3 is (1-4) = -3 and the output of the adder 43 is -3 + 1 = -2 ≡ 3 (mod5), which is represented by the symbol T ³ (C). It is indicated that the code is traversed three bits to the right of the sign T ⁰ (C) = C, which is exactly the calculated phase offset value.

As described above, when the period according to the present invention is n and the number of elements of "0" or "-1" is k, binary which satisfies the condition of gcd (n, k) = 1 or gcd (n, 2k) = 1 Since the phase offset of the code can be directly calculated and calculated, the calculation amount can be drastically reduced as compared with a method of finding a phase offset by matching a conventional PN code code one-to-one, thereby implementing phase offset calculation with a simple hardware structure.

Therefore, when the method of calculating the phase offset of the present invention is applied to mobile communication using a CDMA system, the subscriber (or mobile station) can directly calculate the phase offset by the base station without the help of a base station to adjust the phase offset. Soft handoff can be performed directly to reduce the usage of the base station. When adapting to mobile communication using a CTDMA system, the subscriber can know the phase offset information used by other subscribers. Subscribers themselves can set the phase offset or channel that is not used by other subscribers themselves, which can reduce the workload of the base station.

Claims (6)

Receiving a binary code T ⁱ (C) circulating in a period n; Calculating a binary code weighted accumulation value by setting the accumulation function weight l of the binary code and applying the weight to the binary code; Phase shifting the binary code weighted accumulation value; And calculating the phase offset of the binary code by performing an n operation on the modulated weighted accumulation value. The method of claim 1, The binary code T ⁱ (C) is when i = j (mod n), T ⁱ (C) = T ^j (C) =, i.e. (C _ni , C _{n-i + 1,} ?? C _ni-1 ) = (C _nj , C _{n-j + 1} , ??, C _{nj- 1} ) relationship is established, T ^j (C) is the polynomial C (x) = C _nj + C _{n-j + 1} X,... + C _nj-1 X ^n-1 , where i and j are integers. The method of claim 1, The step of calculating the binary code weighted accumulation value The process of adding the value of delaying the k-1th bit by one bit to the kth bit of the binary encoding received at t = kTb and then accumulating the addition value to the k-1th bit to the nth bit Iteratively obtaining an accumulated value for the weight l, Obtaining a weighting value by multiplying the addition value at t = kTb with l-1 (where l is a weight); And calculating the binary code weighted accumulation value by adding the accumulated value and the weighted value. The method of claim 1, The step of making the phase shift value When the element of the binary code C is {0,1}, the algebraic inverse a ^* of nk for modulo n with a ^* (nk) = 1 (modn) is obtained, and then the inverse a is added to the phase shift value. ^A method of calculating a phase offset of a binary code characterized by multiplying by ^* . The method of claim 1, The step of making the phase shift value When the element of the binary code C is {-1, 1}, the phase shift is obtained after calculating the algebraic inverse a ^* of n-2k for modulo n with a ^* (n-2k) = 1 (modn). And calculating a value by multiplying the inverse a ^* by a value. Receiving the same binary symbols T ^X (C), T ^Y (C) having period n and having different phase offsets X, Y; Obtaining the two yiwonbu favor accumulation function sets the weight to each of s, l, and by using this, the two yiwonbu weighted accumulated value of the arc ^{A S (T X (C)} ) and ^{A l {T Y (C)} }; If the elements of the two binary codes are {-1,1}, then the algebraic inverse a ^* with a ^* (n-2k) = 1 (modn) is set; if {0,1}, a ^* (nk) = 1 (mod setting an algebraic inverse a ^* of n); Phase shift the two weighted accumulation values A ^S (T ^X (C)) and A ^l (T ^Y (C)) using the algebraic inverse a ^{* and} then calculate the difference a ^* A ^S (T ^X (C)) calculating a ^* A ^l (T ^Y (C)); A ^* A ^S (T ^X (C))-A ^* A ^l (T ^Y (C)), and adding a difference of weights ls to perform a module n operation to output the phase offset XY of two binary codes. Phase offset calculation method of binary code, characterized in that.