WO2008116413A1

WO2008116413A1 - Method and device to generate zero correlation zone code, transmitting spreading code and receiving spreading code

Info

Publication number: WO2008116413A1
Application number: PCT/CN2008/070495
Authority: WO
Inventors: Aiping Huang; Jing Li; Ping Li; Hebing Wu; Jibin Wang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-03-27
Filing date: 2008-03-13
Publication date: 2008-10-02
Also published as: CN101277125B; CN101277125A

Abstract

A method and device to generate zero correlation zone codes, a method and device to generate transmitting spreading codes and a method and device to generate receiving spreading codes are provided, which belong to the field of communication coding. The method to generate zero correlation zone codes comprises: combining the original m sequence, i.e. the linear feedback shift register sequence with the maximum length, and the sequence {1} to be a basic code (102); spreading the basic code, generating a zero correlation zone code (104). The method to generate transmitting spreading codes comprises: spreading the basic code generated by using the original m sequence and the sequence {1}, generating a zero correlation zone code; inserting non-zero protecting intervals into the zero correlation zone code, generating a transmitting spreading code.

Description

Method and apparatus for generating zero correlation area code, transmitting spreading code and receiving spreading code

The present invention relates to the field of communication coding, and more particularly to a method and apparatus for generating a zero correlation zone code, a method and apparatus for generating a transmission spreading code, and a method and apparatus for generating a reception spreading code. Background technique

Codes applied in communication systems usually meet certain performance requirements in order to achieve their specific functions. For example, in a communication system using direct sequence spread spectrum technology, a user sequence is spread and despread with a code sequence, and different users are identified by different code sequences. In order to support multiple users sharing the same frequency band and the same time slot, the number of spreading codes used to identify users should be as much as possible. The spreading code should have certain characteristics in order to propagate in multipath such as wireless channel.

Under the condition of (multipath propagation), the orthogonal division of the signals of different users is realized, that is, the signals of different users do not interfere with each other. If the non-periodic autocorrelation function side lobes of any one of the spreading codes are zero, then multiple copies of the signal arriving via different paths can be separated, ie without multipath interference. If the aperiodic cross-correlation function of any two spreading codes is zero, the signals of different users arriving via different paths can be separated, that is, there is no multiple access interference. If both the autocorrelation function and the cross-correlation function of the spreading code have the above-mentioned ideal correlation characteristics under both synchronous and asynchronous conditions, no multiple access interference and no multipath interference can be achieved in the uplink and downlink. Thereby, the spectrum efficiency and system capacity of the communication system using the direct sequence spread spectrum technology under multipath propagation conditions such as a wireless channel can be improved.

The current theory has proved that any single code with a sufficient number of codes cannot have both ideal autocorrelation and cross-correlation properties, and multiple codes capable of simultaneously having ideal autocorrelation properties and cross-correlation properties, such as fully complementary codes, in quantity Very limited. In order to achieve a compromise between the number of codes and the anti-interference ability, a type of code having an ideal correlation characteristic in a certain interval, that is, a zero correlation area code (ZCZ 5 horse, Zero Correlation Zone 53⁄4) can be generated. The ZCZ code belongs to a multi-code, that is, one code is composed of a plurality of sub-codes, and the correlation function is defined as the sum of the correlation functions of the sub-codes. The ZCZ code has ideal autocorrelation properties and cross-correlation properties in a certain interval, that is, the aperiodic cross-correlation function is zero in an interval near the zero offset, and the aperiodic autocorrelation function is in a region near the zero offset. The side lobes are zero. This interval is called zero correlation zone or interference free window (IFW, Interference Free Window), and the length is not greater than the subcode length. The ZCZ code is used as the spreading code. As long as the length of the zero correlation zone is not less than the maximum delay of the system, no multipath interference and no multiple access interference can be realized. Here, the maximum delay of the system is defined as the sum of the maximum multipath delay spread of the propagation channel and the maximum time difference between different user signals in the communication system. Currently, a two-phase zcz code, or a binary ZCZ code, is usually generated by orthogonal matrix recursive extension. The specific steps include: First, selecting a pair of complementary codes, each code containing two equal length subcodes; then, using the pair of codes as basic codes, recursively expanding with an orthogonal matrix until the generation The required number of two-phase ZCZ codes.

Because each extension makes the subcode length double, so that the length of the zero correlation region is doubled, so the subcode length of the existing two-phase ZCZ code can only be an integer power of 2, and the length of the zero correlation region is always an integer of two. power. However, the actual system maximum delay is mostly not an integer power of 2. To ensure the interference-free performance of the system, the zero correlation zone length of the ZCZ code often exceeds the maximum delay of the system, for example, the maximum delay of the system is 5 chip widths. (chip duration, in seconds), the length of the zero-correlation zone of the existing two-phase ZCZ code (in chip width) needs to be 8.

The number of two-phase ZCZ codes is inversely proportional to the length of the zero-correlation zone. Therefore, the length of the zero-correlation zone of the existing two-phase ZCZ code is always an integer power of 2, and the length of the zero-correlation zone larger than the maximum delay of the system is selected, resulting in excessive anti-interference ability, and the code is The number is too small, that is, the number of actually available ZCZ codes is limited.

Moreover, in a communication system using direct sequence spread spectrum technology, when a spread spectrum gain is given, the code length of the spread spectrum address code is determined, since the existing zero correlation area length can only be limited to be larger than the actual system. The maximum delay is an integer power of 2, and thus, the spread code address code having the zero correlation region generated by the existing two-phase ZCZ code has a limited number of available codes, that is, in a direct sequence spread spectrum communication system. The number of users who can support no multipath interference and no multiple access interference is limited. Summary of the invention

In order to improve the spectrum efficiency and system capacity of a communication system under multipath propagation conditions such as a wireless channel, an embodiment of the present invention provides a method and apparatus for generating a zero correlation zone code, a method and apparatus for generating a transmission spreading code, and A method and apparatus for generating a received spreading code. The technical solutions are as follows:

A method of generating a zero correlation zone code, the method comprising:

The initial maximum length linear feedback shift register sequence m sequence and sequence { 1 } are combined into a base code; the base code is extended to produce a zero correlation zone code.

A method for generating a transmission spreading code, the method comprising:

Extending the basic code generated by the initial m sequence and the sequence { 1 } to generate a zero correlation zone code;

A non-zero guard interval is inserted in the zero correlation zone code to generate a transmit spreading code.

A method of generating a received spreading code, the method comprising:

Inserting an all-zero guard interval in the zero-correlation area code used to transmit the spreading code, and generating and transmitting the spreading code has zero The receiving spread code of the relevant area.

A device for generating a zero correlation zone code, the device for generating a zero correlation zone code comprising a base code generation module and an expansion module;

The basic code generating module is configured to generate a basic code by using an initial m sequence and a sequence { 1 }, and input the generated basic code into the expansion module;

And the expansion module is configured to expand the basic code input by the basic code generating module to obtain a zero correlation area code.

An apparatus for generating a transmission spreading code, the apparatus for generating a transmission spreading code comprising a zero correlation area code generating module and a transmission spreading code generating module;

The zero correlation area code generating module is configured to expand a basic code generated by using an initial m sequence and a sequence { 1 }, generate a zero correlation area code, and input the generated zero correlation area code to the transmission extension. Frequency code generation module;

The transmit spreading code generating module is configured to insert a non-zero guard interval into the zero-correlation area code input by the zero-correlation area code generating module to generate the transmit spreading code.

An apparatus for generating a received spreading code, the apparatus for generating a received spreading code comprising a zero correlation area code generating module and a receiving spreading code generating module;

The zero correlation area code generating module is configured to expand a basic code generated by using an initial m sequence and a sequence { 1 }, generate a zero correlation area code, and input the generated zero correlation area code to the received spreading code. Generating a module;

The receiving spreading code generating module is configured to insert an all-zero guard interval in the zero-correlation area code used for transmitting the spreading code, and generate a receiving spreading code having a zero correlation area with the transmitting spreading code.

The technical solution in the embodiment of the present invention, after extending the basic code composed of the initial m sequence and the sequence { 1 }, generates each zero-related region code in the zero-correlation region code set, and the length of the zero-correlation region does not have to be an integer of two. The power can be flexibly selected according to the maximum delay of the system, so the number of available codes of the zero correlation area code can be increased, and the number of available codes of the spreading code is increased, thereby improving the performance of the communication system. DRAWINGS

1 is a flowchart of a method for generating a zero-correlation area code according to Embodiment 1 of the present invention;

2 is a schematic structural diagram of an apparatus for generating a zero-correlation area code according to Embodiment 1 of the present invention;

3 is a flowchart of a method for generating a transmission spreading code according to Embodiment 2 of the present invention;

4 is a schematic structural diagram of an apparatus for generating a transmission spreading code according to Embodiment 2 of the present invention;

5 is a flowchart of a method for generating a received spreading code according to Embodiment 3 of the present invention;

6 is a schematic structural diagram of an apparatus for generating a receiving and spreading code according to Embodiment 3 of the present invention; 7 is a maximum user of a direct sequence spread spectrum code division multiple access (DS-CDMA) communication system using a method provided by Embodiment 23 of the present invention for transmitting and receiving a spreading code and a prior art spreading code. A schematic diagram of the comparison of the number curves. detailed description

The present invention will be further described in detail below with reference to the drawings and specific embodiments.

Example 1

FIG. 1 is a flowchart of a method for generating a zero correlation zone code according to an embodiment of the present invention. In this embodiment, the initial m sequence and the sequence { 1 } are combined into a basic code, and the basic code is extended by performing a leftward cyclic shift on the initial m sequence in the basic code. This embodiment specifically includes the following steps. :

Step 101: Select the initial m sequence.

The maximum length linear feedback shift register sequence, abbreviated as m sequence, is a commonly used pseudo-random sequence with good periodic autocorrelation properties. The following formula (1) gives the period of the m-sequence of period N. Correlation function definition: [ N, / = 0, ±N, ±2N ......

H ^m -1 / _≠ 0 ±N ±2N ^{( 1 )} where integer/represents the relative shift of the sequence ^m ', "represents the jth chip in sequence ¹ ^, (·) Ν denotes (·) mode The value of Ν.

It can be seen from equation (1) that the periodic autocorrelation function is equal to Ν in the zero or integer period, and is equal to -1 at other positions, that is, the periodic autocorrelation function of the m-sequence is equal to the period of the sequence. The sidelobe value is always equal to -1. Therefore, when the period of the sequence is large, the m-sequence is close to the ideal pseudo-random sequence and has good periodic autocorrelation properties.

In this embodiment, the length of the m sequence is determined to be the actual required code sequence length minus 1 according to the actual required code sequence length.

Step 102: Combine the selected m sequence and the sequence { 1 } into a basic code.

In this embodiment, an initial m-sequence ^{m of} length Ν is selected. As the first subcode, the sequence { 1 乍 is the second subcode. Combine these two subcodes into a basic code, denoted as ¹ ^ ^ m ¹ ], where ", " is used to separate the subcode ^m . And subcode { 1 }

The basic code of this embodiment is a multi-code composed of two sub-codes of unequal length, and the code length is the length of two sub-codes. And, that is, the code length L=N+1. According to the characteristics of the autocorrelation function of the m-sequence and the definition of the multi-code autocorrelation function, that is, the autocorrelation function of the multi-code is equal to the sum of the autocorrelation functions of the sub-codes, and the cross-correlation function of the multi-code is equal to the sum of the cross-correlation functions of the subcodes. , can get a period of ¹ ^ period autocorrelation function is:

N + 1, 1 = 0

RE ₀ E ₀ (/) = R _mimi ( + Rn(/) = { '丄, ^ _n

+ ^{≠ Υ} (2) where, the integer 1 represents the sequence ^m . The relative shift of the autocorrelation function shows that the main lobe value is N + l, and the side lobe values are -1 + 1, that is, both are zero.

Step 103: Select the length of the zero correlation zone.

In this embodiment, the length of the zero correlation zone is selected according to the maximum delay of the system obtained by the operation. The method for selecting the length of the zero correlation zone includes: dividing the system chip width by the maximum delay of the system, obtaining the maximum number of delay chips, adding 1 to the maximum delay chip number as the minimum value, and using the initial m sequence length as Maximum value, select a positive integer between the minimum and maximum values as the zero correlation zone length.

In this embodiment, the minimum value is taken as the length of the zero correlation zone. Let the maximum delay of the system be », the chip width be ^, the length of the zero correlation zone be a positive integer, and the length of the smallest zero correlation zone be a positive integer m. According to the maximum delay of the system obtained by measurement or calculation, the method of selecting the length of the zero correlation zone It is obtained by the following formula:

Where L ^x " represents the largest integer not greater than X.

Step 104: Perform a leftward cyclic shift expansion on the basic code to generate a zero correlation area code.

The method for expanding the basic code to generate the zero-correlation region code includes: cyclically shifting the initial m sequence in the basic code to the left or right, and combining the cyclically shifted m sequence with the sequence {1} to generate Zero related area code.

In the present embodiment, the zero-correlation area code is generated by the method of cyclic shift to the left: The basic code = m sequence ^m in [ ^m ° , ¹ ]. The dish is rotated to the left, and the obtained extended sequence is denoted as ^m ^k = 0 to K - l), and the nth chip of the extended sequence ^mfc is represented as a He leg. Since ¹ ^ is made by ^m . By cyclically shifting to the left, and according to the definition of the periodic autocorrelation function of the m-sequence according to formula (1), it can be concluded that the main lobe value of the autocorrelation function of the extended sequence ¹ ^ is N, and the sidelobe value is -1. Therefore, after performing cyclic shift to the left by the basic code, the m sequence cyclically shifted to the left is combined with the sequence {1} to generate the kth zero correlation region code in the zero correlation region code set in this embodiment. =[m _fe 'l ], whose autocorrelation function has a main lobe value of N+1 and sidelobe values of zero. Similarly, this embodiment can also be used for ^m . Rotate the extension to the right, and the resulting extension code, then its autocorrelation function The number of main lobe values is also N+l, and the side lobe values are also zero.

After cyclically shifting the base code to the left or right, the chip extension can be obtained by K.

Code of related characteristics

In the middle, the periodic cross-correlation function between any two different codes and ^ has the following characteristics:

In the formula, integer/represents the relative shift between sequences. It can be seen that when the relative shift/satisfaction l ^z l ^{< f} dish, any two different codes have an ideal cross-correlation property, that is, a code obtained by expanding the same basic code, at a certain In the relevant area, there is an ideal correlation characteristic, that is, a zero correlation area code.

In this embodiment, the initial m sequence is taken as the first subcode, the sequence { 1 乍 is the second subcode, and a basic code is synthesized, and the side lobe value of the m sequence autocorrelation function is -1, so that the basic code is obtained. Has ideal autocorrelation properties.

The zero correlation zone code generated in this embodiment has a zero correlation zone length of ^. Moreover, since the embodiment of the present invention extends the basic code by cyclically shifting to the left or right, the length of the zero correlation zone may take any positive integer between the minimum zero correlation zone length m and the initial _m sequence length N, not necessarily 2 The power of the integer. Therefore, the zero-correlation area code generated by the method of the embodiment of the present invention has a zero-correlation area length that can be flexibly selected according to the maximum delay of the actual system, and the number of available codes is more than the existing two-phase ZCZ code.

FIG. 2 is a schematic structural diagram of an apparatus for generating a zero-correlation area code according to an embodiment of the present invention, where the apparatus includes a basic code generation module 210 and an expansion module 220;

The basic code generating module 210 is configured to generate a basic code by using an initial m sequence and a sequence { 1 }, and input the generated basic code into the expansion module 220;

The expansion module 220 expands the basic code input by the basic code generation module 210 to obtain a plurality of zero correlation area codes.

The expansion module 220 includes a selection unit 221 and an execution unit 222.

The selecting unit 221 is configured to: according to the maximum delay of the system obtained by the operation or measurement, select the zero correlation zone length, and input the selected zero correlation zone length to the execution unit 222;

The executing unit 222 cyclically shifts the initial m sequence in the basic code input by the basic code generating module to the left or right of the zero correlation region by zero or a positive integer multiple of the length of the zero correlation region according to the length of the zero correlation region input by the selecting unit 221 sheet.

Example 2 FIG. 3 is a flowchart of a method for generating a transmission spreading code according to an embodiment of the present invention. In this embodiment, the basic code is generated by using the m sequence and the sequence {1}, and the initial m sequence in the basic code is cyclically shifted to the left. The embodiment specifically includes the following steps:

Steps 301 - Step 304 The steps of generating the zero correlation zone code are the same as steps 101 - 104, which are not described here.

Step 305: Insert a non-zero guard interval in the zero correlation area code to generate a transmission spreading code.

The preset guard interval length in this embodiment is the maximum delay chip number m ^{_ 1} determined by the system maximum delay divisible chip width, and the purpose of inserting the guard interval is to separate two subcodes in the zero correlation zone code. , so that they do not overlap each other after multipath propagation. The method of inserting the non-zero guard interval in the zero-correlation area code is: according to the preset guard interval length ^ ¹ - copy sequence ¹ ^ end ^ dish - ¹ chip, get the cyclic prefix ^m f of the sequence ¹ ^, ^ ^ ¹ replication sequences starting dish - ¹ chip to obtain the cyclic suffix sequence ¹ ^ sequence is inserted before the cyclic prefix ^m f, inserting a cyclic suffix sequence after ¹ ^^; ^ dish of length - ¹ of all 1 sequence, the sequence {1} cyclic prefix 1, insertion sequence {1} before, of length ^ dish - all 1 ^sequence, the sequence {1} cyclic suffix 1, {1} is inserted sequence; finally, A transmission spread code = [ ^{mr mk mr χΡ η 1 ∞} ] is ^generated . In this embodiment, a code set composed of all spreading codes is used as the generated transmission spreading code set.

The following describes a method for generating a transmission spreading code by using a specific numerical example, where the method specifically includes:

First, select the initial m sequence.

Assuming that the actual required code length L=16, an initial m sequence of length N=L-1 = 15 should be selected, assuming the selected m-sequence ^m . = (11:11, eleven, eleven, ten, ten), "ten" means 1, "one" means one.

Then, the basic code is generated using the initial m sequence and the sequence {1}.

The basic code generated is: = (11:11:11:11:10, +), where "," is used to separate the sequence ^m . And sequence {1}.

Next, select the length of the zero correlation zone. Assume that the length of the zero correlation zone is selected ^^^^^^ ⁷ " ^{+ 1 = 3} .

Then, for ^m . Perform a leftward shift of the dish chip to obtain a zero correlation area code set, including

Eleven one eleven eleven ten ten ten, ten

Ιθ

Ί = (11:11, eleven, eleven, ten, eleven, one, ten

0

' ² =< : one eleven eleven ten ten ten ten eleven, ten

' ³ = (one eleven ten ten forty one one ten ten, ten

0

' ⁴ = ( : ten ten ten forty one ten + eleven, ten

Finally, a non-zero guard interval is inserted in the zero correlation zone code to generate a transmission spreading code. Sending a spread code set Including the following 5 transmit spreading codes:

, eleven, eleven, eleven, eleven, ten, ten, ten

One eleven one eleven eleven ten ten ten eleven one one, one ten, ten,

One, one eleven eleven ten ten ten ten eleven, one ten

, eleven ten ten ten forty one ten, ten,

Ten — ten ten ten eleven eleven eleven eleven

Where, italics represent the cyclic prefix and the cyclic suffix, separated by ", "

Sequence { 1 }, cyclic prefix, and cyclic suffix.

4 is a schematic structural diagram of an apparatus for generating a transmission spreading code according to an embodiment of the present invention, where the apparatus includes a zero correlation area code generating module 410, and a transmission spreading code generating module 420;

The zero correlation area code generating module 410 expands the basic code generated by using the initial m sequence and the sequence { 1 } to generate a zero correlation area code, and inputs the generated zero correlation area code to the transmission spreading code generating module 420;

The transmit spreading code generating module 420 inserts a non-zero guard interval into the zero-correlation area code input by the zero-correlation area code generating module 410 to generate a transmission spreading code.

Example 3

FIG. 5 is a flowchart of a method for generating a received spreading code according to an embodiment of the present invention. The steps of generating a zero-correlation area code in steps 501 to 504 are the same as steps 301-304, and are not described here.

Step 505: Insert an all-zero guard interval in the zero-correlation area code to generate a receive spreading code.

In this embodiment, an all-zero guard interval is inserted in the zero-correlation area code used for transmitting the spreading code, and a received spreading code having a zero correlation area with the transmitted spreading code is generated.

The preset guard interval length in this embodiment is the maximum number of delay chips m ^{_ 1} determined by the maximum delay of the system, and the method of inserting the all-zero guard interval is: according to the preset guard interval length

¹ ^ before spreading sequence, the average length of the insertion ^ all - 1 0 ¹ sequence; {1} sequence before and after each insertion ^ _mm length - 00 with the full sequence not Xiang column ^1, most.晷铢The final production ρ^φ is generated, ψ, and the receiving spread 疖 frequency m code 3⁄4 _ L" ^m * ^{υ υ 1 υ In} this embodiment, all the received spreading codes ^E [formed code sets are generated as Receiving a set of spreading codes,

In the following, the method used in the second embodiment is taken as an example to describe a method for generating a received spreading code.

First, use the same method to generate a zero-correlation area code:

0

E

= (10 - eleven, eleven, eleven, ten, ten, ten)

(11:11, eleven, eleven, ten, eleven, one, ten)

E° _{2 :} :(一十一十一十一十十十十一,十)

(11, eleven, ten, eleven, ten, ten) 4 = (ten tenty one eleven one eleven eleven, ten)

Then, an all-zero guard interval is inserted in the zero-correlation area code to obtain a received spreading code.

The received spreading code set includes the following five receiving spreading codes:

^Ε ο=( ΟΟ,Η 1 hH——I——h ten, 00, 00, ten, 00)

^{Ε ι = (00, -H hH--} I-- h + + H, 00, 00, ten, 00)

^E = (00, - + H - I - h + + H h -, 00, 00, ten, 00)

h 十十十 1 h+, 00, 00, ten, 00)

^E ^=(00, + + + H 1 hH——h— , 00, 00, ten, 00)

According to the second and third embodiments of the present invention, a method for transmitting and receiving a spreading code is generated, and the aperiodic autocorrelation function of the spreading code can be defined as: transmitting a spreading code ¹ ^ and receiving extension in the spreading code set A non-periodic correlation function corresponding to the received spreading code ^ in the frequency code set.

Meanwhile, the spreading code may be aperiodic cross-correlation function is defined as: send a spreading code set a spreading code transmission and receiving ^E ^ received spreading code set ^a spreading code ^ aperiodic correlation functions Ρ ^≠ .

6 is a schematic structural diagram of an apparatus for generating a received spreading code according to an embodiment of the present invention, where the apparatus includes a zero correlation area code generating module 610 and a receiving spreading code generating module 620;

The zero correlation area code generating module 610, the base code generated by using the initial m sequence and the sequence {1} is extended to generate a zero correlation area code, and the generated zero correlation area code is input to the receiving spreading code generating module 620;

The receiving spreading code generating module 620 inserts an all-zero guard interval in the zero-correlation area code used for transmitting the spreading code, and generates a receiving spreading code having a zero correlation area with the transmitting spreading code.

The method for generating a transmitting and receiving spreading code provided by the second and third embodiments of the present invention fills the zero-correlation area code with different pre- and post-suffixes to obtain a transmission spreading code and a receiving spreading code in which a zero-correlation area exists. And the length of the zero correlation zone may be any positive integer smaller than the length of the initial m sequence, and the transmission spreading code and the received spreading code are used in the communication system using the direct sequence spread spectrum technology, in avoiding multipath interference and multiple access At the same time as interference, it can support more users.

7 is a transmission and reception spreading code generated by the method provided by the second and third embodiments of the present invention and a spreading code in the prior art in a direct sequence spread spectrum code division multiple access (DS-CDMA) communication system. A comparison of the maximum user number curves, see Figure 7, in the case of different spreading gains G (equal to the length of the ZCZ code) and different system maximum delay ax, when ax is 3 chip widths and 5 chips In the case of the width, the number of users that can be supported in the DS-CDMA communication system by using the second and third embodiments of the present invention is greatly improved compared with the LS-CDMA system using the LS code. Because of the system maximum delay for non-two integer powers, the second and third embodiments of the present invention generate a set of transmit and receive spreading codes that are much larger than the LS code set. And « is 4 (SP2 The ratio of the number of transmission and reception spread codes generated by the second and third embodiments of the present invention when the power of the integer is one chip width

The number of LS codes is small, so the number of users that can be supported is less. In most cases, the DS-CDMA communication system using the spreading code generated by the second and third embodiments of the present invention can support more users.

The zero correlation zone code generated by the embodiment of the present invention may be used to generate a spreading code, an address code, and other codes or symbols. The transmitting and receiving spreading codes generated by the embodiments of the present invention may be used to include direct sequence spread spectrum, direct sequence spread spectrum code division multiple access, time division/code division hybrid multiple access, frequency division/code division hybrid multiple access or space division. In a communication system of code division hybrid multiple access, it is used as a spreading code or a spread spectrum address code.

The above are only the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for generating a zero-correlation area code, the method comprising:

The method for generating a zero-correlation area code according to claim 1, wherein the expanding the basic code to generate a zero-correlation area code specifically includes:

The initial m sequence in the basic code is cyclically shifted to the left or right, and the cyclically shifted m sequence and the sequence { 1 } are combined to generate the zero correlation region code.

The method for generating a zero-correlation area code according to claim 2, wherein the cyclically shifting the initial m sequence in the basic code to the left or right includes:

According to the maximum delay of the system obtained by operation or measurement, the length of the zero correlation zone is selected;

The initial m sequence in the base code is cyclically shifted left or right, the number of bits of the cyclic shift being equal to zero or a positive integer multiple of the length of the zero correlation zone.

The method for generating a zero-correlation region code according to claim 3, wherein the length of the zero correlation region selected according to the maximum delay of the system obtained by the operation or measurement specifically includes:

Using the maximum delay of the system to divide the chip width of the system, obtaining the maximum number of delay chips, and adding the maximum delay chip number to 1, as a minimum value;

Taking the length of the initial m sequence as a maximum value;

A positive integer between the minimum value and the maximum value range is selected as the zero correlation zone length.

A method for generating a transmission spreading code, the method comprising:

The method for generating a transmission spreading code according to claim 5, wherein the expanding the basic code generated by using the initial m sequence and the sequence { 1 } to generate the zero correlation area code specifically includes:

Performing a leftward or rightward cyclic shift on the initial m sequence in the basic code;

Combining the cyclically shifted m sequence with the sequence { 1 } produces the zero correlation zone code.

The method for generating a transmission spreading code according to claim 6, wherein the inserting the non-zero guard interval in the zero-correlation region code, and generating the transmission spreading code comprises:

Record the length of the preset guard interval as X;

Inserting a cyclic prefix obtained by copying X chips at the end of the m-sequence before the m-sequence of the zero-correlation region code, Inserting a cyclic suffix obtained by starting X chips from the m-sequence of the zero-correlation area code, inserting an all-one sequence of length X before the sequence { 1 } of the zero-correlation area code, in the zero correlation Inserting an all-one sequence of length X after the sequence of the area code;

The sequence after the non-zero guard interval is inserted as the generated transmission spreading code.

The method for generating a transmission spreading code according to claim 7, wherein the preset guard interval length is specifically:

The maximum number of delay chips determined by the maximum delay of the system to divide the chip width.

9. A method of generating a received spreading code, the method comprising:

An all-zero guard interval is inserted in the zero-correlation area code used to transmit the spreading code, and a received spreading code having a zero correlation area with the transmitted spreading code is generated.

The method for generating a received spreading code according to claim 9, wherein the step of expanding the basic code generated by using the initial m sequence and the sequence { 1 } to generate a zero correlation area code specifically includes:

The method for generating a received spreading code according to claim 10, wherein the generating the spreading code having the zero correlation area with the transmitting spreading code comprises:

Inserting an all-zero sequence of length X before and after the m-sequence of the zero-correlation area code used for transmitting the spreading code according to the preset guard interval length X, the zero used in transmitting the spreading code The sequence of the relevant area code { 1 } is inserted into the all-zero sequence of length X before and after;

The sequence after the all zero guard interval is inserted as the generated received spreading code.

The method for generating a received spreading code according to claim 11, wherein the preset guard interval length is specifically:

13. Apparatus for generating a zero correlation zone code, the apparatus comprising a base code generation module and an expansion module;

And the expansion module is configured to expand the basic code input by the basic code generation module to obtain a zero correlation area code.

14. The apparatus for generating a zero correlation zone code according to claim 13, wherein said expansion module comprises an option Take the unit and the execution unit;

The selecting unit is configured to: according to the maximum delay of the system obtained by the operation or measurement, select a length of the zero correlation zone, and input the selected zero correlation zone length into the execution unit;

The executing unit is configured to cyclically shift the initial m sequence in the basic code input by the basic code generating module to the left or right according to the length of the zero correlation region input by the selecting unit, the cyclic shift The number of bits is equal to zero or a positive integer multiple of the length of the zero correlation zone, thereby obtaining the zero correlation zone code.

15. An apparatus for generating a transmission spreading code, the apparatus comprising a zero correlation area code generating module and a transmission spreading code generating module;

An apparatus for generating a received spreading code, the apparatus comprising a zero correlation area code generating module and a receiving spreading code generating module;