CN106850485A - The generation method of frequency-domain OFDM symbol - Google Patents
The generation method of frequency-domain OFDM symbol Download PDFInfo
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- CN106850485A CN106850485A CN201611106875.5A CN201611106875A CN106850485A CN 106850485 A CN106850485 A CN 106850485A CN 201611106875 A CN201611106875 A CN 201611106875A CN 106850485 A CN106850485 A CN 106850485A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/2605—Symbol extensions, e.g. Zero Tail, Unique Word [UW]
- H04L27/2607—Cyclic extensions
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2602—Signal structure
- H04L27/261—Details of reference signals
- H04L27/2613—Structure of the reference signals
Abstract
The invention discloses a kind of generation method of frequency-domain OFDM symbol, the generation method of wherein frequency-domain OFDM symbol includes：Determine the average power ratio of fixed sequence program and signaling sequence；Generate fixed sequence program and signaling sequence set respectively on frequency domain according to average power ratio R；A signaling sequence is selected from signaling sequence set, fixed sequence program and signaling sequence are filled to effective subcarrier, and arranged in oem character set between fixed sequence program and signaling sequence；Null sequence subcarrier is filled respectively in effective subcarrier both sides to form the frequency-domain OFDM symbol of predetermined length；Wherein, sequence number of the selected signaling sequence in set is the signaling information of OFDM symbol carrying, the technical program is solved in current DVB_T2 standards and other standards, and the problem of probability of failure occurs in leading symbol low complex degree receiving algorithm detection under frequency selective fading channels.
Description
Technical field
The present invention relates to wireless broadcast communication technical field, the generation method and thing of more particularly to a kind of frequency-domain OFDM symbol
The generation method of leading symbol in reason frame.
Background technology
The data transmitted by transmitting terminal are correctly demodulated generally for the receiving terminal for enabling ofdm system, ofdm system is necessary
Realize between transmitting terminal and receiving terminal accurately and reliably time synchronized.Simultaneously as ofdm system is very quick to the frequency deviation of carrier wave
Sense, the receiving terminal of ofdm system it is also required to provide the carrier spectrum method of estimation of precise and high efficiency, be carried out accurately with to carrier wave frequency deviation
Estimation and correction.
At present, realize that transmitting terminal and the synchronous method of destination time are substantially come real based on leading symbol in ofdm system
Existing.Leading symbol is all known symbol sebolic addressing of transmitting terminal and receiving terminal of ofdm system, and leading symbol is as physical frame
Start (being named as P1 symbols), only occur a P1 symbol or continuous appearance multiple P1 symbols in each physical frame, it indicates
The beginning of the physical frame.The purposes of P1 symbols is included：
1) whether receiving terminal is rapidly detected with determine to transmit in channel is the signal expecting to receive；
2) basic configured transmission (such as FFT points, frame type information etc.) is provided, so that receiving terminal can carry out rear continued access
Receipts treatment；
3) original carrier frequency deviation and timing error are detected, frequency and Timing Synchronization is reached after compensating；
4) emergency alarm or broadcast system wake up.
The P1 Design of Symbols based on CAB spatial structures is proposed in DVB_T2 standards, above-mentioned functions are preferably realized.But
It is still have some to limit on low complex degree receiving algorithm.For example, in 1024,542 or 482 multipath long letters of symbol
During road, being timed using CAB structures slightly synchronously can occur relatively large deviation, cause to estimate that carrier wave integer frequency offset occurs on frequency domain
Mistake.In addition, in complex frequency Selective Fading Channel, such as during multipath long, DBPSK differential decodings are likely to fail.
Being additionally, since in DVB_T2 spatial structures does not have Cyclic Prefix, and if need the frequency-domain structure for carrying out channel estimation to combine, will make
Into the problem of its channel estimation in frequency domain performance degradation.
The content of the invention
During the problem that the present invention is solved is current DVB_T2 standards and other standards, without circulation in DVB_T2 spatial structures
Prefix, it is impossible to receive and calculate suitable for relevant detection, and leading symbol low complex degree under complex frequency Selective Fading Channel
There is the problem of probability of failure in method detection.
To solve the above problems, a kind of generation method of frequency-domain OFDM symbol is the embodiment of the invention provides, including it is as follows
Step：Determine the average power ratio R of fixed sequence program and signaling sequence；According to the average power ratio, generation is fixed respectively on frequency domain
Sequence and signaling sequence set；A signaling sequence is selected from signaling sequence set, fixed sequence program and the signaling sequence are filled out
It is charged on effective subcarrier, and is arranged in oem character set between the fixed sequence program and signaling sequence；In effective subcarrier
Fill null sequence subcarrier respectively to form the frequency-domain OFDM symbol of predetermined length in both sides；Wherein, selected signaling sequence is in collection
Sequence number in conjunction is the signaling information of OFDM symbol carrying.
The embodiment of the present invention additionally provides a kind of generation method of leading symbol in physical frame, comprises the following steps：To pre-
The frequency-domain OFDM symbol of measured length makees inverse discrete fourier transform to obtain time-domain OFDM symbol；Wherein, the frequency-domain OFDM symbol
Number obtained according to the generation method of above-mentioned frequency-domain OFDM symbol；From the time-domain OFDM symbol interception circulating prefix-length when
Domain OFDM symbol is used as Cyclic Prefix；The time-domain OFDM symbol generation modulation letter of the circulating prefix-length based on above-mentioned interception
Number；Leading symbol is generated based on the Cyclic Prefix, the time-domain OFDM symbol and the modulated signal.
Compared with prior art, technical solution of the present invention has the advantages that：
The generation method of the frequency-domain OFDM symbol for providing according to embodiments of the present invention, by fixed sequence program and signaling sequence with strange
Even mode staggeredly is filled to effective subcarrier, is designed by so specific frequency-domain structure, and wherein fixed sequence program can be made
It is the pilot tone in physical frame, consequently facilitating receiving terminal carries out decoding demodulation to leading symbol in the physical frame that receives.
Further, in the method for generating fixed sequence program on frequency domain, each element is that mould is fixed in fixed sequence program
Value, and argument is the plural number of arbitrary value between 0 to 2 π.In generating the method for signaling sequence set on the frequency domain, signaling sequence
Number is 2 integral number power, and length and number based on signaling sequence determine the root values in CAZAC sequences generation formula, really
The digit k of fixed a different set of q values and corresponding cyclic shift, and thus it is calculated signaling sequence.
And, inventor has obtained an effect and has preferably fixed signaling, one group of effect preferably signaling sequence in practice
The position of 128 groups of q values of selection and cyclic shift in the length and number of row and corresponding four root values and each root value
Number.So that the leading symbol being subsequently generated has relatively low papr (Peak to Average Power
Ratio, PAPR), and improve the probability of success that receiving terminal detects leading symbol.
Further, by the use of the modulated signal of time-domain OFDM symbol and the structure of time-domain OFDM symbol (as leading character
Number) ensure that in receiving terminal using the related peak value that may be significantly of delay.Also, during the leading symbol is generated,
Design time-domain OFDM symbol modulated signal can avoid receiving terminal be subject to continuous wave CO_2 laser or mono-tone interference, or occur with
Occur when protection interval length is identical with modulated signal length in the isometric multipath channel of modulated signal length, or reception signal
Error detection peak value.
Brief description of the drawings
Fig. 1 is a kind of schematic flow sheet of the specific embodiment of the generation method of frequency-domain OFDM symbol of the invention；
Fig. 2 is that the flow of the specific embodiment of the generation method of leading symbol in a kind of physical frame of the invention is illustrated
Figure；
Fig. 3 is the spatial structure schematic diagram of leading symbol in a kind of physical frame of the invention.
Specific embodiment
Inventor has found in current DVB_T2 standards and other standards that leading symbol is low under frequency selective fading channels
There is the problem of probability of failure in the detection of complexity receiving algorithm.In addition, there is no Cyclic Prefix in DVB_T2 spatial structures, it is impossible to suitable
For relevant detection, and leading symbol low complex degree receiving algorithm detection appearance failure under frequency selective fading channels is general
The problem of rate.
Regarding to the issue above, inventor is by research, there is provided the generation method and frequency of leading symbol in a kind of physical frame
The generation method of domain OFDM symbol, it is ensured that carrier frequency offset receiving terminal in the range of -500kHz to 500kHz can still be processed
Receive signal.
It is understandable to enable the above objects, features and advantages of the present invention to become apparent, below in conjunction with the accompanying drawings to the present invention
Specific embodiment be described in detail.
As shown in Fig. 1 a kind of flow of the specific embodiment of the generation method of frequency-domain OFDM symbol of the invention is shown
It is intended to.With reference to Fig. 1, the generation method of frequency-domain OFDM symbol comprises the following steps：
Step S11：Determine the average power ratio R of fixed sequence program and signaling sequence；
Step S12：Fixed sequence program and signaling sequence set are generated respectively on frequency domain according to average power ratio R；
Step S13：A signaling sequence is selected from signaling sequence set, by fixed sequence program and the signaling sequence fill to
Arranged in oem character set on effective subcarrier, and between the fixed sequence program and signaling sequence；
Step S14：Fill null sequence subcarrier respectively to form the frequency domain of predetermined length in effective subcarrier both sides
OFDM symbol；Wherein, sequence number of the selected signaling sequence in set is the signaling information that the OFDM symbol is carried.
Specifically, as described in step S11, the average power ratio R of fixed sequence program and signaling sequence is determined.Wherein, it is described
Fixed sequence program can be used to do relevant information, the signaling sequence of carrier frequency synchronization and Timing Synchronization in set including receiving terminal
Interior sequence is used to carry each basic configured transmission.
Wherein, the average power ratio R of fixed sequence program and signaling sequence can be adjusted according to practical application request, be selected larger
R obtains more preferable channel estimation and whole inclined estimation performance to increase the power of fixed sequence program, or selects less R to increase
The power of signaling sequence improves the actual signal to noise ratio on signaling carrier so as to improve signaling decoding performance.Therefore, fixed sequence program
It is according to whole inclined estimation performance, channel estimating performance, solution signaling performance and Timing Synchronization with the average power ratio R of signaling sequence
The equilibrium of energy considers and determines.
In the present embodiment, the average power ratio R of the fixed sequence program and signaling sequence is 1.When fixed sequence program length and
When signaling sequence length is identical, average power ratio is the ratio between power summation.
It is determined that after average power ratio, being just accordingly fixed the Amplitude Ration of sequence and signaling sequence.As average power ratio R
It is 1, and fixed sequence program and signaling sequence, when being permanent mode sequence, the Amplitude Ration of corresponding fixed sequence program and signaling sequence is
As described in step S12, fixed sequence program and signaling sequence collection are generated respectively on frequency domain according to average power ratio R
Close.
In the present embodiment, fixed sequence program being generated on frequency domain can be realized using following concrete mode：
Step S121：Determine the length of fixed sequence program；Wherein, each element in the fixed sequence program for mould be fixed
Value, and argument is the plural number of arbitrary value between 0 to 2 π.
It should be noted that in the present embodiment, the half of the length less than OFDM symbol length of the fixed sequence program.
Step S122：A fixed sequence program is selected from all optional fixed sequence programs, and is generated with good from phase
The signaling sequence set of closing property and cross correlation, and based on any signaling sequence institute group in the fixed sequence program and signaling sequence set
Into OFDM symbol by meeting required power PAR after inverse fourier transform.
Specifically, above-mentioned fixed sequence program all valued spaces (i.e. each element for mould be definite value, and argument is 0
To the plural number of arbitrary value between 2 π) in, preferably go out a fixed sequence program.The fixed sequence program selected needs to meet：By the fixation sequence
The signaling sequence set of column-generation has good autocorrelation and cross correlation, and based on the fixed sequence program and signaling sequence
The frequency-domain OFDM symbol that any signaling sequence in set is constituted is by having relatively low power peak after inverse fourier transform
Than (Peak-to-Average Power Ratio, PAPR), and the concrete numerical value (or number range) of the power PAR can
To be determined according to system requirements.
In the present embodiment, signaling sequence set being generated on frequency domain can be realized using following concrete mode：
Step S123：Determine the length of signaling sequence and the number of contained signaling sequence in signaling sequence set；Wherein, institute
The number for stating signaling sequence is 2 n times power, and N is positive integer；
Step S124：Signaling sequence in generation M signaling sequence subclass, and each signaling sequence subclass respectively
Number is respectively m1~mM, and
Step S125：Whole signaling sequences in each signaling sequence subclass are arranged together forming letter in order
Make arrangement set；And it is 0~2 to numberN-1；
Wherein, the root values of each signaling sequence subclass are different, the width of each element in all signaling sequences
Degree is element amplitude in fixed sequence program
Further, the present embodiment generates the preferred of each signaling sequence subclass in giving above-mentioned steps S124
Implementation method, it is specific as follows：
Step S1241：Number based on the signaling sequence determines the root values in CAZAC sequences generation formula；Wherein
Twice of the root values more than or equal to the number of signaling sequence.
In practice, root is prime number, and preferably root=L, and the autocorrelation value of such sequence is zero.
Step S1242：According to selected root values, a different set of q values generation CAZAC sequences of selection, wherein q values
Number is equal to the number of signaling sequence, the value of q values be integer and more than 0 less than root values, any two q value sums
In root values；
Step S1243：Displacement is circulated to produced CAZAC sequences；Wherein, the digit of cyclic shift is by corresponding
Root values and q values are determined.
In actual applications, the digit selection of q values and cyclic shift should cause to have between all signaling sequences low mutual
Correlation, and the frequency-domain OFDM symbol for being constituted is by having low power PAR (Peak- after inverse fourier transform
To-Average Power Ratio, PAPR).
Step S1244：Needed for the digit of number, q values and cyclic shift according to identified signaling sequence is calculated
Signaling sequence subclass.
For example, determine fixed sequence program and signaling sequence length L, root value, and preferred one group of q value and one group of circulation
Digit (the q of displacementi,ki, i=0~2N- 1), i-th generation formula method of signaling sequence：
First, CAZAC sequences are generated：
Then, displacement is circulated to it：
si *(n)=[s (ki-1),s(ki),...,S(root-1),s(0),...,s(ki-1)]
Finally, intercepted length is the sequence of L since the head of above-mentioned sequence：
SCi(n)=si *(n), n=0~L-1
Resulting sequence SCiN () is i-th required signaling sequence.
For example, determine that average power ratio R is 1；Fixed sequence program length is 353, and amplitude is 1, for being calculated
Preferably fixed sequence program, such as following formula is represented：
Wherein, ωnValue it is as shown in the table by rows from left to right in order：
The number of signaling sequence is determined for 512, and the signaling sequence set includes 4 signaling sequence subclass, each
Signaling sequence subclass includes 128 signaling sequences, and the length of signaling sequence is 353.
According to above-mentioned fixed sequence program, the parameter calculated in each signaling sequence subclass used by signaling sequence is as follows respectively：
1) first root value of signaling sequence subclass is 353；
The value of q values is all numerical value in following form：
| 1 | 9 | 10 | 16 | 18 | 21 | 28 | 29 | 32 | 35 | 49 | 51 | 53 | 54 | 55 |
| 57 | 59 | 60 | 61 | 65 | 68 | 70 | 74 | 75 | 76 | 77 | 78 | 82 | 84 | 85 |
| 86 | 88 | 90 | 95 | 96 | 103 | 113 | 120 | 123 | 125 | 126 | 133 | 134 | 135 | 137 |
| 138 | 140 | 141 | 142 | 145 | 147 | 148 | 150 | 151 | 155 | 156 | 157 | 161 | 163 | 165 |
| 167 | 170 | 176 | 178 | 179 | 181 | 182 | 184 | 185 | 187 | 194 | 200 | 201 | 204 | 209 |
| 210 | 217 | 222 | 223 | 224 | 225 | 229 | 232 | 234 | 235 | 237 | 239 | 241 | 244 | 246 |
| 247 | 248 | 249 | 251 | 252 | 253 | 254 | 255 | 262 | 270 | 272 | 273 | 280 | 282 | 290 |
| 291 | 306 | 307 | 308 | 309 | 311 | 313 | 314 | 315 | 317 | 320 | 326 | 327 | 330 | 331 |
| 333 | 336 | 338 | 340 | 342 | 345 | 347 | 349 |
The digit of cyclic shift is all numerical value in following form：
2) second root value of signaling sequence subclass is 367；
The value of q values is all numerical value in following form：
| 8 | 9 | 10 | 15 | 19 | 21 | 31 | 34 | 39 | 49 | 58 | 59 | 71 | 76 | 80 |
| 119 | 120 | 121 | 123 | 140 | 142 | 151 | 154 | 162 | 166 | 171 | 184 | 186 | 188 | 190 |
| 191 | 193 | 194 | 195 | 198 | 203 | 204 | 207 | 208 | 209 | 210 | 211 | 212 | 214 | 215 |
| 219 | 220 | 221 | 222 | 223 | 224 | 226 | 228 | 230 | 232 | 233 | 235 | 236 | 237 | 239 |
| 240 | 241 | 243 | 245 | 249 | 250 | 252 | 254 | 257 | 259 | 260 | 261 | 262 | 263 | 264 |
| 265 | 266 | 267 | 269 | 271 | 272 | 273 | 275 | 276 | 277 | 278 | 281 | 282 | 283 | 284 |
| 285 | 286 | 289 | 294 | 297 | 299 | 302 | 303 | 306 | 307 | 310 | 311 | 312 | 313 | 314 |
| 316 | 317 | 321 | 322 | 323 | 326 | 327 | 329 | 331 | 332 | 334 | 338 | 340 | 342 | 344 |
| 345 | 347 | 349 | 351 | 356 | 361 | 363 | 366 |
The digit of cyclic shift is all numerical value in following form：
| 198 | 298 | 346 | 271 | 345 | 324 | 160 | 177 | 142 | 71 | 354 | 290 | 69 | 144 | 28 |
| 325 | 100 | 55 | 237 | 196 | 271 | 210 | 187 | 277 | 8 | 313 | 53 | 53 | 194 | 294 |
| 36 | 202 | 69 | 25 | 18 | 179 | 318 | 149 | 11 | 114 | 254 | 191 | 226 | 138 | 179 |
| 341 | 366 | 176 | 64 | 50 | 226 | 23 | 181 | 26 | 327 | 141 | 244 | 179 | 74 | 23 |
| 256 | 265 | 223 | 288 | 127 | 86 | 345 | 304 | 260 | 139 | 312 | 62 | 360 | 107 | 201 |
| 301 | 263 | 257 | 184 | 329 | 300 | 81 | 121 | 49 | 196 | 201 | 94 | 147 | 346 | 179 |
| 59 | 212 | 83 | 195 | 145 | 3 | 119 | 152 | 310 | 31 | 134 | 54 | 187 | 131 | 63 |
| 276 | 294 | 142 | 246 | 54 | 181 | 121 | 273 | 276 | 36 | 47 | 16 | 199 | 243 | 235 |
| 194 | 348 | 95 | 262 | 52 | 210 | 115 | 250 |
3) the 3rd root value of signaling sequence subclass is 359；
The value of q values is all numerical value in following form：
The digit of cyclic shift is all numerical value in following form：
| 300 | 287 | 80 | 119 | 68 | 330 | 93 | 359 | 17 | 93 | 355 | 308 | 106 | 224 | 20 |
| 18 | 226 | 165 | 320 | 339 | 352 | 316 | 241 | 336 | 119 | 166 | 258 | 273 | 302 | 275 |
| 46 | 26 | 259 | 330 | 206 | 46 | 10 | 308 | 165 | 195 | 314 | 330 | 208 | 148 | 275 |
| 15 | 214 | 251 | 8 | 27 | 264 | 169 | 128 | 207 | 21 | 246 | 14 | 291 | 345 | 114 |
| 306 | 179 | 109 | 336 | 322 | 149 | 270 | 253 | 207 | 152 | 26 | 190 | 128 | 137 | 196 |
| 268 | 36 | 40 | 253 | 29 | 264 | 153 | 221 | 341 | 116 | 24 | 55 | 60 | 171 | 25 |
| 100 | 202 | 37 | 93 | 115 | 174 | 239 | 148 | 170 | 37 | 328 | 37 | 253 | 237 | 355 |
| 39 | 288 | 225 | 223 | 140 | 163 | 145 | 264 | 75 | 29 | 282 | 252 | 270 | 30 | 262 |
| 271 | 305 | 122 | 78 | 27 | 127 | 92 | 6 |
4) the 4th root value of signaling sequence subclass is 373；
The value of q values is all numerical value in following form：
| 26 | 28 | 29 | 34 | 38 | 40 | 43 | 49 | 54 | 57 | 58 | 62 | 64 | 65 | 79 |
| 80 | 81 | 83 | 85 | 86 | 87 | 101 | 102 | 187 | 189 | 190 | 191 | 193 | 194 | 195 |
| 196 | 198 | 199 | 200 | 202 | 204 | 205 | 206 | 208 | 209 | 211 | 213 | 214 | 216 | 217 |
| 218 | 219 | 220 | 221 | 222 | 223 | 224 | 225 | 227 | 228 | 230 | 232 | 233 | 236 | 237 |
| 241 | 243 | 245 | 246 | 247 | 248 | 249 | 250 | 251 | 252 | 253 | 255 | 256 | 259 | 260 |
| 261 | 262 | 263 | 265 | 266 | 267 | 275 | 276 | 280 | 282 | 283 | 284 | 285 | 289 | 295 |
| 297 | 300 | 301 | 302 | 303 | 305 | 307 | 317 | 320 | 322 | 323 | 325 | 327 | 328 | 332 |
| 338 | 341 | 342 | 343 | 348 | 349 | 351 | 352 | 353 | 355 | 356 | 357 | 358 | 359 | 360 |
| 361 | 362 | 363 | 364 | 367 | 369 | 370 | 372 |
The digit of cyclic shift is all numerical value in following form：
As described in step S13, a signaling sequence is selected from signaling sequence set, by fixed sequence program and the signaling sequence
Arranged in oem character set on filling to effective subcarrier, and between the fixed sequence program and signaling sequence.
In one preferred embodiment, the equal length of the length of the fixed sequence program and the signaling sequence, and
1/2 of the length less than the predetermined length.Wherein, the predetermined length be can also be according to being in 1024, but practical application
System demand and change.
So that predetermined length is 1024 as an example, if the length of fixed sequence program is L (carries effective subcarrier of fixed sequence program
Number is L), the length of signaling sequence be P (i.e. the number of effective subcarrier of carrier signaling sequence is P), in the present embodiment,
L=P.In other embodiments, L can also be slightly larger than P.
Between the fixed sequence program and signaling sequence in oem character set arrange, i.e., fixed sequence program fill to even subcarrier (or
Strange subcarrier) on position, correspondingly, signaling sequence is filled to strange subcarrier (or even subcarrier) position, so as in frequency domain
The distribution of fixed sequence program and the arrangement of signaling sequence oem character set is presented on effective subcarrier.It should be noted that when fixation
(such as P when the length of sequence and signaling sequence is inconsistent>L), can realize fixing by way of zero padding sequence subcarrier
Sequence and signaling sequence oem character set are arranged.
As described in step S14, fill null sequence subcarrier respectively to form predetermined length in effective subcarrier both sides
Frequency-domain OFDM symbol：Wherein, sequence number of the selected signaling sequence in set is the signaling letter that the OFDM symbol is carried
Breath.
In one preferred embodiment, this step includes：Equal length is filled respectively in effective subcarrier both sides
Null sequence subcarrier forming the frequency-domain OFDM symbol of predetermined length.
Along to the example that predetermined length is 1024, the G=1024-L-P of the length of null sequence subcarrier, both sides filling
(1024-L-P)/2 null sequence subcarrier.
Further, in order to ensure that receiving terminal can still be located in the range of -500kHz to 500kHz in carrier frequency offset
Reason receives signal, and the value of (1024-L-P)/2 is typically larger than critical length value (being set to TH), and the critical length value is by system symbol
Rate and predetermined length determine.For example, system symbol rate of the predetermined length for 1024,7.61M, the sample rate of 9.14M, thenFor example, L=P=353, then G=318, both sides are respectively filled
159 null sequence subcarriers.
Therefore, subcarrier (i.e. frequency-domain OFDM symbol) P1_X of predetermined length (1024)0,P1_X1,…,P1_X1023By
In the following manner filling generation：
Wherein, fixed sequence program subcarrierSignaling sequence subcarrierResiding odd even position can exchange.
As shown in Fig. 2 in a kind of physical frame of the invention the specific embodiment of the generation method of leading symbol stream
Journey schematic diagram.With reference to Fig. 2, the generation method of leading symbol comprises the following steps in physical frame：
Step S21：Frequency-domain OFDM symbol to predetermined length makees inverse discrete fourier transform to obtain time-domain OFDM symbol；
Wherein, the frequency-domain OFDM symbol is obtained according to the generation of the generation method of above-mentioned frequency-domain OFDM symbol；
Step S22：Time-domain OFDM symbol from time-domain OFDM symbol interception circulating prefix-length is used as Cyclic Prefix；
Step S23：The time-domain OFDM symbol generation modulated signal of the circulating prefix-length based on above-mentioned interception；
Step S24：Leading symbol is generated based on the Cyclic Prefix, the time-domain OFDM symbol and the modulated signal.
In the present embodiment, as described in step S21, the frequency-domain OFDM symbol to predetermined length makees inverse discrete fourier transform
To obtain time-domain OFDM symbol.
Inverse discrete fourier transform described in this step is the conventional mode that frequency-region signal is converted into time-domain signal,
It will not go into details for this.
P1_XiTime-domain OFDM symbol is obtained after making inverse discrete fourier transform：
Wherein, L is fixed sequence program
The number of carrier wave, P is the number of signaling sequence carrier wave, and R is the average power ratio of fixed sequence program and signaling sequence.
As described in step S22, the time-domain OFDM symbol from time-domain OFDM symbol interception circulating prefix-length is used as following
Ring prefix.
In the present embodiment, the circulating prefix-length is equal to or less than the predetermined length.With the predetermined length
As a example by 1024, the circulating prefix-length can be 1024 or less than 1024.Preferably, the circulating prefix-length is
520, the latter half (length is 520) of the time-domain OFDM symbol is generally intercepted as Cyclic Prefix, so as to solve frequency domain letter
Estimate the problem of hydraulic performance decline in road.
Wherein, it is described to determine that circulating prefix-length is many path lengths that confrontation is generally needed according to wireless broadcast communication system
Degree, system can obtain the bit of minimum length and spatial structure the transmission signaling of robust correlation peak in minimum threshold level
Any one or more factor in number determines.If only needing to transmit signaling in frequency-domain structure, and spatial structure is fixed and nothing
Signaling need to be transmitted, then only needs to consider that the multipalh length for needing confrontation, system can obtain robust relevant peaks in minimum threshold level
One of minimum length of value or two.Generally, the length of Cyclic Prefix is more long, and the performance for resisting multipath long is better, and
The length and modulated signal length of Cyclic Prefix are more long, and it postpones related peak value and gets over robust.Generally, the length of Cyclic Prefix and
Modulated signal length need to be more than or equal to the minimum length that system can obtain robust correlation peak in minimum threshold level.
As described in step S23, the time-domain OFDM symbol generation modulation letter of the circulating prefix-length based on above-mentioned interception
Number.In practice, the general length without departing from Cyclic Prefix part of modulated signal length.
Specifically, this step includes：
1) a frequency deviation sequence is set；
2) by the time domain OFDM of the time-domain OFDM symbol of the circulating prefix-length or the part circulating prefix-length
Symbol is multiplied by the frequency deviation sequence to obtain the modulated signal.
For example, setting NcpIt is the circulating prefix-length for determining, LenBIt is modulated signal length.Modulated signal length is existed by system
The minimum length of robust correlation peak can be obtained during minimum threshold level to determine.Usual modulated signal length is more than or equal to this most
Small length.If NAIt is the length of time-domain OFDM symbol, if sampled point serial number 0,1 ... the N of time-domain OFDM symbolA- 1. set N1 as
Selection is copied to the sampled point sequence number of the corresponding time-domain OFDM symbol of starting point of modulated signal section, and N2 is copied to modulation letter for selection
The corresponding time-domain OFDM symbol sampled point sequence number of terminal of number section.Wherein,
N2=N1+LenB-1
For the ease of description, time-domain OFDM symbol is divided into 2 parts, first paragraph is not intercepted as the part of Cyclic Prefix
Time-domain OFDM symbol (the generally front portion of the time-domain OFDM symbol), second segment is part time domain of the interception as Cyclic Prefix
OFDM symbol (the generally rear portion of the time-domain OFDM symbol).If interception time-domain OFDM symbol is all as Cyclic Prefix, the
One section of length is 0.N1 necessarily falls in second segment, that is, select the scope of the part time-domain OFDM symbol to modulated signal section
Without departing from the scope intercepted as the part time-domain OFDM symbol of Cyclic Prefix.
Modulated signal part, Cyclic Prefix part are identical with a part of information in time-domain OFDM symbol.Wherein, modulation letter
Number part is only to have modulated frequency deviation or other signals, therefore can utilize the correlation of modulated signal part and Cyclic Prefix part
And Timing Synchronization and small inclined estimation are done in modulated signal part with the correlation of time-domain OFDM symbol.In practice, modulation letter
Number length is usually no more than circulating prefix-length.If modulated signal length is more than circulating prefix-length, the part for exceeding will increase
The expense of adding system, causes the decline of efficiency of transmission, and it to be only capable of enhanced modulation signal section related to time-domain OFDM symbol
The robustness of value, under the expense for maintaining like, this partial-length should increase to Cyclic Prefix part, and it will bring more
Performance benefits.
As shown in figure 3, A segment tables show time-domain OFDM symbol, C segment tables show Cyclic Prefix, and B segment tables show modulated signal.The frequency deviation
Sequence isWherein fSHThe corresponding subcarrier in frequency domain interval (i.e. 1/ of time-domain OFDM symbol can be chosen for
NAT), wherein T is sampling period, NAIt is the length of time-domain OFDM symbol.In this example, NAIt is 1024, takes fSH=1/1024T.
In other instances, in order that correlation peak is sharp, fSHIt is 1/ (Len that can also selectBT).Work as LenB=NCPWhen, fSH=1/
NCPT.Such as LenB=NCPWhen=512, fSH=1/512T.
In other embodiments, M (t) can also be designed to other sequences, such as m-sequence or some window sequences for simplifying
Deng.
The modulated signal of the part time-domain OFDM symbol is P1_B (t), and P1_B (t) is by the part time-domain OFDM symbol
It is multiplied by frequency deviation sequence M (t) to obtain, i.e., P1_B (t) is：
Wherein, N1 is that selection is copied to modulated signal section
The sampled point sequence number of the corresponding time-domain OFDM symbol of starting point.
As described in step S24, generated based on the Cyclic Prefix, the time-domain OFDM symbol and the modulated signal leading
Symbol.
Specifically, using Cyclic Prefix splicing in the front portion of the time-domain OFDM symbol as protection interval, and by institute
State modulated signal to splice at the rear portion of the OFDM symbol as frequency modulation sequence to generate leading symbol, as shown in Figure 3.
For example, leading symbol can be according to using following time-domain expression：
In a preferred embodiment, the predetermined length NAWhen=1024, Ncp=520, LenB=504, N1 be 504 or
520。
Although the present invention is disclosed as above with preferred embodiment, it is not for limiting the present invention, any this area
Technical staff without departing from the spirit and scope of the present invention, may be by the methods and techniques content of the disclosure above to this hair
Bright technical scheme makes possible variation and modification, therefore, every content without departing from technical solution of the present invention, according to the present invention
Any simple modification, equivalent variation and modification for being made to above example of technical spirit, belong to technical solution of the present invention
Protection domain.
Claims (7)
1. a kind of generation method of frequency-domain OFDM symbol, it is characterised in that comprise the following steps：
Determine the average power ratio R of fixed sequence program and signaling sequence；
Fixed sequence program and signaling sequence set are generated respectively on frequency domain according to average power ratio R；
Fixed sequence program and the signaling sequence are filled to effective subcarrier, and in strange between the fixed sequence program and signaling sequence
Occasionally it is staggered or is occasionally very staggered；
Null sequence subcarrier is filled respectively to form the frequency-domain OFDM symbol of predetermined length in effective subcarrier both sides,
Wherein, fixed sequence program is generated on frequency domain to comprise the following steps：
Determine the length of fixed sequence program；Wherein, each element in the fixed sequence program for mould be definite value, and argument is 0 to 2
The plural number of arbitrary value between π；
A fixed sequence program is selected from all optional fixed sequence programs, and is generated with good autocorrelation and cross correlation
Signaling sequence set, and existed based on the OFDM symbol that any signaling sequence in the fixed sequence program and signaling sequence set is constituted
By meeting required power PAR after inverse fourier transform.
2. the generation method of frequency-domain OFDM symbol as claimed in claim 1, it is characterised in that signaling sequence is generated on frequency domain
Set includes：
Determine the length of signaling sequence and the number of contained signaling sequence in signaling sequence set；Wherein, the signaling sequence
Number is 2 n times power, and N is positive integer；
The number of the signaling sequence in generation M signaling sequence subclass, and each signaling sequence subclass is respectively m respectively1~
mM, and
Whole signaling sequences in each signaling sequence subclass are arranged together forming signaling sequence set in order；
Wherein, the root values of each signaling sequence subclass are different, and the amplitude of each element is in all signaling sequences
Element amplitude in fixed sequence program
3. the generation method of frequency-domain OFDM symbol as claimed in claim 2, it is characterised in that generate each signaling sequence
Set includes：
Number based on the signaling sequence determines the root values in CAZAC sequences generation formula；Wherein root values be more than or
Equal to the twice of the number of signaling sequence；
According to selected root values, a different set of q values are selected to produce CAZAC sequences, the wherein number of q values to be equal to signaling sequence
The number of row, the value of q values for integer and more than 0 less than root values, any two q value sums are not equal to root values；
Displacement is circulated to produced CAZAC sequences；Wherein, the digit of cyclic shift is determined by corresponding root values and q values
It is fixed；
The digit of number, q values and cyclic shift according to identified signaling sequence is calculated required signaling sequence subset
Close.
4. the generation method of frequency-domain OFDM symbol as claimed in claim 1, it is characterised in that the fixed sequence program and signaling sequence
The average power ratio R of row is 1.
5. the generation method of frequency-domain OFDM symbol as claimed in claim 1, it is characterised in that the fixed sequence program length is
353, mould is 1, and expression formula is：
Wherein, ωnValue it is as shown in the table by rows from left to right in order：
6. the generation method of frequency-domain OFDM symbol as claimed in claim 2, it is characterised in that the signaling sequence set for being generated
The number of middle signaling sequence is 512, and the signaling sequence set includes 4 signaling sequence subclass, each signaling sequence subset
The signaling sequence number that conjunction is included is 128, and the length of signaling sequence is 353.
7. the generation method of frequency-domain OFDM symbol as claimed in claim 3, it is characterised in that each signaling sequence subclass
Parameter is：
1) first root value of signaling sequence subclass is 353；
The value of q values is all numerical value in following form：
The digit of cyclic shift is all numerical value in following form：
2) second root value of signaling sequence subclass is 367；
The value of q values is all numerical value in following form：
The digit of cyclic shift is all numerical value in following form：
3) the 3rd root value of signaling sequence subclass is 359；
The value of q values is all numerical value in following form：
The digit of cyclic shift is all numerical value in following form：
4) the 4th root value of signaling sequence subclass is 373；
The value of q values is all numerical value in following form：
The digit of cyclic shift is all numerical value in following form：
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| US9843845B2 (en) | 2012-11-28 | 2017-12-12 | Sinclair Broadcast Group, Inc. | Terrestrial broadcast market exchange network platform and broadcast augmentation channels for hybrid broadcasting in the internet age |
| US9866421B2 (en) | 2014-08-07 | 2018-01-09 | ONE Media, LLC | Dynamic configuration of a flexible orthogonal frequency division multiplexing PHY transport data frame |
| EP3178187A1 (en) | 2014-08-07 | 2017-06-14 | Coherent Logix, Incorporated | Multi-partition radio frames |
| WO2016033059A1 (en) | 2014-08-25 | 2016-03-03 | ONE Media, LLC | Dynamic configuration of a flexible orthogonal frequency division multiplexing phy transport data frame preamble |
| KR102500030B1 (en) | 2015-03-09 | 2023-02-16 | 원 미디어, 엘엘씨 | System discovery and signaling |
| KR102232751B1 (en) | 2015-04-08 | 2021-03-29 | 원 미디어, 엘엘씨 | Advanced data cell resource mapping |
| EP3440787A1 (en) | 2016-04-07 | 2019-02-13 | Sinclair Broadcast Group, Inc. | Next generation terrestrial broadcasting platform aligned internet and towards emerging 5g network architectures |
| CN106230543B (en) * | 2016-08-02 | 2018-05-08 | 江苏中兴微通信息科技有限公司 | Cycle targeting sequencing generation method based on ZC sequences |
| CN112532368B (en) * | 2017-11-16 | 2021-08-20 | 华为技术有限公司 | Sequence-based signal processing method and signal processing device |
| CN111490957B (en) * | 2020-03-10 | 2023-06-16 | 北京睿信丰科技有限公司 | Method and device for generating preamble sequence in time domain |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1791084A (en) * | 2004-12-17 | 2006-06-21 | 清华大学 | Time-domain synchronous OFDM space-frequency coding time-frequency combination channel estimating method |
| US20100135149A1 (en) * | 2008-12-03 | 2010-06-03 | Samsung Electronics Co., Ltd. | System and method for in-phase/quadrature multiplexing |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101383793B (en) * | 2007-09-03 | 2013-01-30 | 华为技术有限公司 | Method, apparatus and system for signal transmission and channel estimation |
| US8208522B2 (en) * | 2008-03-07 | 2012-06-26 | Nokia Corporation | System and methods for receiving OFDM symbols having timing and frequency offsets |
| CN103532899B (en) * | 2013-07-31 | 2016-07-06 | 上海数字电视国家工程研究中心有限公司 | Time domain OFDM synchronizing symbol generates and demodulation method, data frame transmission method |
| CN110190938B (en) * | 2014-05-28 | 2022-07-12 | 上海数字电视国家工程研究中心有限公司 | Method for generating preamble symbol in physical frame |
-
2014
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1791084A (en) * | 2004-12-17 | 2006-06-21 | 清华大学 | Time-domain synchronous OFDM space-frequency coding time-frequency combination channel estimating method |
| US20100135149A1 (en) * | 2008-12-03 | 2010-06-03 | Samsung Electronics Co., Ltd. | System and method for in-phase/quadrature multiplexing |
Non-Patent Citations (1)
| Title |
|---|
| LIFENG HE等: "Robust Physical Layer Signaling Transmisssion over OFDM Systems", 《IEICE TRANSACTIONS ON COMMUNICATIONS》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019111242A1 (en) * | 2017-12-06 | 2019-06-13 | Xinow Ltd. | Audio transmission and reception |
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