CN1960358A - Digital information transmission method of a kind of multicarrier digital mobile multimedia broadcast system - Google Patents

Abstract

The method comprises: after sequentially making RS coding and byte interlace, LDPC coding, bit interlace and constellation mapping for the upper layer data, the acquired data symbol, discrete pilot frequency and the continuous polite frequency are multiply connected to form OFDM polite frequency and make scrambling; generating OFDM symbol through IFFT transformation, and after forming time slot through inserting frame head, they are connected to form signal frame of physical layer; after making low pass filter and quadrature up-conversion for the physical layer signal frame, they are sent out. The invention can provide radio broadcast such as audio, video and multicast for mobile, fixed and portable receiver. The system thereof uses micro wave and large-scale IC technology. The method adopts OFDM of LDPC solution.

Description

A kind of digital information transmission method of kind of multicarrier digital mobile multimedia broadcast system

Technical field

The present invention relates to digital information transmission technical field, particularly the information transferring method of DMB.

Background technology

Radio communication broadcasting is except broad covered area, program capacity are big, and maximum characteristics have broadcasting exactly, a bit to multiple spot, point-to-area, has the higher transmission bandwidth under low-cost condition.Therefore, radio communication broadcasting has critical role as an important component part of ICT industry in national information infrastructure construction, realization universal service and national information security strategy.

Through years of researches and development, digital radio broadcast has obtained a lot of achievements, has reached the practical stage, mainly contains four kinds of wireless digital television and broadcast standards at present in the world:

1) digital video broadcasting (Digital Video Broadcasting, i.e. DVB) series standard DVB is proposed by ETS tissue (European Telecommunications StandardsInstitute, i.e. ETSI).Europe is after stopping digital-to-analogue in 1993 and having mixed the research of standard television system; begun the research of digital television broadcasting system; and priority has been issued digital video satellite broadcasting (Digital Video Broadcasting-Satellite; be DVB-S); digital video wired broadcasting (Digital Video Broadcasting-Cable; be DVB-C); digital video broadcast-terrestrial (Digital Video Broadcasting-Terrestrial; be DVB-T) standard and be digital TV hand-held broadcasting (Digital VideoBroadcasting-Handheld, i.e. DVB-H) standard that base growth is come out with DVB-T.

DVB-S standard in the above-mentioned standard adopts single carrier QPSK modulation system, the convolution code that adopts cascade is with the RS sign indicating number, as chnnel coding, employing PRBS pseudo-random bit sequence (Pseudo Random BitSequence, be PRBS) carry out scrambler, use wireless satellite link, be only applicable to fixedly receiving system, be not suitable for mobile terminal device.The DVB-T standard adopts multi-carrier OFDM (Orthogonal Frequency Division Multiplexing, be OFDM) modulation technique and the convolution code of cascade and the coding techniques of RS sign indicating number, be applicable to the Open circuit ground transmission, but the translational speed of supporting is lower.The DVB-H system is with in order to move and hand-held optimization, but since be subjected to DVB-T coding, modulation technique limitation, optimize and insufficient.

2) U.S. ATSC standard

The ATSC standard of the U.S. is (the Advanced Television SystemCommittee of the Advanced Television standard committee, be ATSC) the single-carrier digital television ground transmission standard that proposes, can support the fixedly reception of single-definition and high definition digital television, but the poor-performing under the mobile condition of acceptance, and do not support satellite transmits.

3) Japanese ISDB-T standard

ISDB-T is floor synthetic digital service broadcasting (Integrated Service Digital Broadcasting-Terrestrial) standard that the digital broadcasting expert group of Japan works out, adopt OFDM technology and convolution code, RS sign indicating number to realize the terrestrial broadcasting of multiple digital service, but the poor performance under the mobile condition of acceptance is not supported satellite transmits yet.

4) Japan and Korea S's digital satellite broadcasting standard

In May, 1998, companies such as Toshiba, SKTelecomm, Sharp, Toyota Motor provide funds jointly, set up mobile broadcast company (Mobile Broadcasting Corporation), and launched broadcasting satellite in March, 2004, now start operation, provide service Japan, Korea S.System adopts the concatenated coding that has also used PRBS, band to interweave, and adopts the mode of CDM spread spectrum to transmit.Though Japan and Korea S's digital satellite broadcasting standard can be supported to move and receive, performance is still not ideal enough, remains further to be improved.

Summary of the invention

The present invention be after the deficiency at above-mentioned four kinds of transmission meanss is optimized design, propose a kind of go for multiple environment such as satellite transmits, terrestrial transmission the digital information transmission method of the wireless multi-service broadcasting of integrated form, be used to mobile, portable and fixing reception user that high-quality audio frequency, video and multi-medium data business are provided.

The present invention proposes a kind of digital information transmission method of kind of multicarrier digital mobile multimedia broadcast system, may further comprise the steps:

By RS coding and byte interleaver device upper layer data stream is carried out RS coding and byte-interleaved, wherein, the line number of described byte interleaver device is by constellation mapping mode and the decision of LDPC code check;

To carry out the LDPC coding through the data of byte-interleaved, obtain Bit data by the LDPC encoder;

By bit interleaver the Bit data through the LDPC coding is carried out Bit Interleave;

By constellation mapper the data through Bit Interleave are carried out constellation mapping;

By the frequency domain symbol maker OFDM frequency domain symbol is formed in the data symbol multiple connection of scattered pilot, the continuous pilot that includes system information and above-mentioned process constellation mapping together;

By scrambler the above-mentioned OFDM frequency domain symbol that obtains through multiple connection is carried out scrambler;

By the IFFT converter above-mentioned frequency domain symbol through scrambler is produced the OFDM time-domain symbol through the IFFT conversion;

By the time domain framer with above-mentioned time domain OFDM symbol through after insertion frame head and forming time slot, connect to form the physical layer signal frame;

Above-mentioned physical layer signal frame is carried out launching behind low-pass filtering and the quadrature up-conversion.

Described digital information transmission method is used to transmit the multimedia broadcast data that comprises voice data, text, video data.

This system has adopted the OFDM scheme of LDPC, and system receiver uses state-of-the-art microwave and large-scale digital ic technology, has satisfied low-cost and high performance requirement simultaneously.

Description of drawings

Fig. 1 is the broadcast channel physical layer logic channel architecture figure of mobile multimedia broadcast system of the present invention.

Fig. 2 is the logic channel coding and the modulation flow chart of mobile multimedia broadcast system physical layer of the present invention;

Fig. 3 is divided and frame assumption diagram by the time slot of the formed physical layer signal frame of time slot framing among Fig. 2;

Fig. 4 is the structure chart of beacon among Fig. 3;

Fig. 5 is the pseudo random sequence generator structural representation of synchronizing signal;

Fig. 6 is the structure chart of OFDM symbol among Fig. 3;

The schematic diagram of Fig. 7 for overlapping between the protection at interval;

Fig. 8 is an OFDM symbolic construction schematic diagram;

Fig. 9 be byte interleaver device and RS (240, K) Bian Ma schematic diagram;

Figure 10 is for carrying out the schematic diagram of Bit Interleave to process LDPC bit stream coded;

Figure 11,12 and 13 is respectively BPSK constellation mapping figure, QPSK constellation mapping figure and 16QAM constellation mapping figure;

Figure 14 is a pilot tone multiple connection mode schematic diagram of the subcarrier allocation of OFDM symbol being given data symbol, scattered pilot and continuous pilot;

Figure 15 is the schematic diagram of PRBS generation method;

Figure 16 is an OFDM symbol sub-carrier structure schematic diagram.

Embodiment

The present invention can provide the multimedia programming that comprises high-quality digital audio broadcasting, digital video broadcasting.

The present invention has defined in every 2MHz frequency band, can broadcast each functional module of physical layer that upper layer data stream carries out adaptation processing to mobile multimedia broadcast system, provide frame structure, chnnel coding, the modulation technique of mobile multimedia broadcasting channel physical layer transmission signal.

Physical layer is the bottom of OSI, is the basis of whole open system.Physical layer provides transmission medium and interconnect equipment for the data communication between the equipment, for transfer of data provides reliable environment.

The broadcast channel physical layer of the present invention's definition is come the different requirements of adaptive upper strata types of applications to transmission rate by the physical layer logic channel.The physical layer logic channel supports multiple coding and modulation system in order to satisfy the different requirements to signal quality of different application, different transmission environment.

The broadcast channel physical layer of the present invention's definition is supported single frequency network and two kinds of networking models of multiple frequency network, MFN, can select different transmission mode and parameter with network environment according to the characteristic of practical application.Support the mixed mode of multiple application, reach the coupling of application characteristic and transmission mode, realized application flexibility and economy.

With reference to the accompanying drawings to a preferred embodiment of the present invention will be described in detail.

Fig. 1 is the broadcast channel physical layer logic channel architecture figure of mobile multimedia broadcast system of the present invention.

As shown in the figure, physical layer provides (comprising control logic channel CLCH and service logical channels SLCH) broadcast channel of upper layer application by physical layer logic channel (Physical Logicl Channel, i.e. PLCH).Each physical layer logic channel can use the one or more time slots in the 2MHz Digital Television bandwidth to send.Physical layer is carried out independent coding and modulation to each physical layer logic channel.Different with modulation parameter according to coding, the physical layer logic channel can provide different transmission capacities.

Fig. 2 is the logic channel coding and the modulation flow chart of mobile multimedia broadcast system physical layer of the present invention.

As shown in the figure, the input traffic of physical layer logic channel through forward error correction coding, interweave and constellation mapping after, carry out OFDM modulation with scattered pilot and continuous pilot multiple connection together.Signal after the modulation forms the physical layer signal frame after inserting frame head.Launch to rf conversion through base band again.

The physical layer logic channel is divided into control logic channel (CLCH) and service logical channels (SLCH).The control logic channel is used for the bearing system configuration information, adopts fixing chnnel coding and modulation pattern to send at system's the 0th time slot, and wherein: the RS coding adopts RS (240,240), the LDPC coding adopts 1/2 code check LDPC coding, and constellation mapping adopts the BPSK mapping, and the scrambler pattern is a pattern 0.One or more time slots that service logical channels can take except that the 0th time slot send, and its coding and modulating mode are by upper-layer configured, and configuration information is by the control logic channel radio.

The detailed description of each submodule sees below described among Fig. 2.

Fig. 3 is divided and frame assumption diagram by the time slot of the formed physical layer signal frame of time slot framing among Fig. 2.

As shown in the figure, the system physical layer signal was 1 frame in per 1 second, and every frame is divided into 40 time slots (Timeslot, i.e. TS), and the length of each time slot is 25ms.

Each time slot comprises 1 beacon and 53 OFDM modulated data blocks.

Fig. 4 is the structure chart of beacon among Fig. 3.

As shown in the figure, beacon comprises 2 identical synchronizing signals and identification signal of transmitter (ID).

Synchronizing signal is the limited pseudo random sequence of frequency band, length is 204.8us, the generating mode of this synchronizing signal is: at first the pseudo random sequence generator by synchronizing signal shown in Figure 5 generates pseudo random sequence, as shown in the figure, this pseudo random sequence generator polynomial is x11+x9+1, and preset value is 01110101101; Intercept preceding 314 points of above-mentioned 2047 m sequences then, adopt the BPSK mapping (0 → 1+0j, 1 →-be placed on the the 1st～157 and the 355th～511 point of 512 point (0～511) sequences after 1+0j); After 512 point sequences of above-mentioned generation are carried out 512 IFFT, obtain synchronizing signal.

Identification signal of transmitter (ID) sends the limited pseudo random sequence of frequency band that is used to identify different transmitters, and length is 36us.The generation method of identification signal of transmitter is: select the sender unit identification sequence; With 37 sender unit identification sequences adopt the BPSK mapping (0 → 1+0j, 1 →-be placed on after 1+0j) on the the 1st～18 and the 45th～63 of 64 point (0～63) sequences; After 64 point sequences of above-mentioned generation are carried out 64 IFFT, and periodic extension to 90 obtains identification signal of transmitter.

Above-mentioned sender unit identification sequence is that length is the pseudo random sequence of 37 bits.The sender unit identification sequence comprises 256 sequences altogether, and wherein sequence 0～sequence 127 is the area sign, is used for the area at marking emitter place, the even number time slot transmission in its insertion signal frame (the 0th time slot, the 2nd time slot ...); Sequence 128～255 is a sender unit identification, is used to identify the different transmitters in the areal, the odd number time slot transmission in its insertion signal frame (the 1st time slot, the 3rd time slot ...).The sender unit identification sequence is defined by hexadecimal sequence, and this hexadecimal sequence is mapped as binary system sender unit identification sequence according to the highest significant bit order formerly, so that enter above-mentioned BPSK mapping step.The sender unit identification sequence is as shown in table 1.

Numbering	The sender unit identification sequence
		0	05B1D0D73D

1	10E4858268
		2	1682E3E40E
3	03D7B6B15B
		4	0ABEDFD832
5	1FEB8A8D67
		6	198DECEB01
7	0CD8B9BE54
		8	1AB12FD7C2
9	0FE47A8297
		10	09821CE4F1
11	1CD749B1A4
		12	15BE20D8CD
13	00EB758D98
		14	068D13EBFE
15	13D846BEAB
		16	1AB1D028C2
17	0FE4857D97
		18	0982E31BF1
19	1CD7B64EA4
		20	15BEDF27CD
21	00EB8A7298
		22	068DEC14FE
23	13D8B941AB

24	05B12F283D
		25	10E47A7D68
26	16821C1B0E
		27	03D7494E5B
28	0ABE202732
		29	1FEB757267
30	198D131401
		31	0CD8464154
32	054E2F28C2
		33	101B7A7D97
34	167D1C1BF1
		35	0328494EA4
36	0A412027CD
		37	1F14757298
38	19721314FE
		39	0C274641AB
40	1A4ED0283D
		41	0F1B857D68
42	097DE31B0E
		43	1C28B64E5B
44	1541DF2732
		45	00148A7267
46	0672EC1401

47	1327B94154
		48	1A4E2FD73D
49	0F1B7A8268
		50	097D1CE40E
51	1C2849B15B
		52	154120D832
53	0014758D67
		54	067213EB01
55	132746BE54
		56	054ED0D7C2
57	101B858297
		58	167DE3E4F1
59	0328B6B1A4
		60	0A41DFD8CD
61	1F148A8D98
		62	1972ECEBFE
63	0C27B9BEAB
		64	18DA44CA81
65	0D8F119FD4
		66	0BE977F9B2
67	1EBC22ACE7
		68	17D54BC58E
69	02801E90DB

70	04E678F6BD
		71	11B32DA3E8
72	07DABBCA7E
		73	128FEE9F2B
74	14E988F94D
		75	01BCDDAC18
76	08D5B4C571
		77	1D80E19024
78	1BE687F642
		79	0EB3D2A317
80	07DA44357E
		81	128F11602B
82	14E977064D
		83	01BC225318
84	08D54B3A71
		85	1D801E6F24
86	1BE6780942
		87	0EB32D5C17
88	18DABB3581
		89	0D8FEE60D4
90	0BE98806B2
		91	1EBCDD53E7
92	17D5B43A8E

93	0280E16FDB
		94	04E68709BD
95	11B3D25CE8
		96	1825BB357E
97	0D70EE602B
		98	0B1688064D
99	1E43DD5318
		100	172AB43A71
101	027FE16F24
		102	0419870942
103	114CD25C17
		104	0725443581
105	12701160D4
		106	14167706B2
107	01432253E7
		108	082A4B3A8E
109	1D7F1E6FDB
		110	1B197809BD
111	0E4C2D5CE8
		112	0725BBCA81
113	1270EE9FD4
		114	141688F9B2
115	0143DDACE7

116	082AB4C58E
		117	1D7FE190DB
118	1B1987F6BD
		119	0E4CD2A3E8
120	182544CA7E
		121	0D70119F2B
122	0B1677F94D
		123	1E4322AC18
124	172A4BC571
		125	027F1E9024
126	041978F642
		127	114C2DA317
128	025DE9AB61
		129	1708BCFE34
130	116EDA9852
		131	043B8FCD07
132	0D52E6A46E
		133	1807B3F13B
134	1E61D5975D
		135	0B3480C208
136	1D5D16AB9E
		137	080843FECB
138	0E6E2598AD

139	1B3B70CDF8
		140	125219A491
141	07074CF1C4
		142	01612A97A2
143	14347FC2F7
		144	1D5DE9549E
145	0808BC01CB
		146	0E6EDA67AD
147	1B3B8F32F8
		148	1252E65B91
149	0707B30EC4
		150	0161D568A2
151	1434803DF7
		152	025D165461
153	1708430134
		154	116E256752
155	043B703207
		156	0D52195B6E
157	18074C0E3B
		158	1E612A685D
159	0B347F3D08
		160	02A216549E
161	17F74301CB

162	11912567AD
		163	04C47032F8
164	0DAD195B91
		165	18F84C0EC4
166	1E9E2A68A2
		167	0BCB7F3DF7
168	1DA2E95461
		169	08F7BC0134
170	0E91DA6752
		171	1BC48F3207
172	12ADE65B6E
		173	07F8B30E3B
174	019ED5685D
		175	14CB803D08
176	1DA216AB61
		177	08F743FE34
178	0E91259852
		179	1BC470CD07
180	12AD19A46E
		181	07F84CF13B
182	019E2A975D
		183	14CB7FC208
184	02A2E9AB9E

185	17F7BCFECB
		186	1191DA98AD
187	04C48FCDF8
		188	0DADE6A491
189	18F8B3F1C4
		190	1E9ED597A2
191	0BCB80C2F7
		192	1BA40A3989
193	0EF15F6CDC
		194	0897390ABA
195	1DC26C5FEF
		196	14AB053686
197	01FE5063D3
		198	07983605B5
199	12CD6350E0
		200	04A4F53976
201	11F1A06C23
		202	1797C60A45
203	02C2935F10
		204	0BABFA3679
205	1EFEAF632C
		206	1898C9054A
207	0DCD9C501F

208	04A40AC676
		209	11F15F9323
210	179739F545
		211	02C26CA010
212	0BAB05C979
		213	1EFE509C2C
214	189836FA4A
		215	0DCD63AF1F
216	1BA4F5C689
		217	0EF1A093DC
218	0897C6F5BA
		219	1DC293A0EF
220	14ABFAC986
		221	01FEAF9CD3
222	0798C9FAB5
		223	12CD9CAFE0
224	1B5BF5C676
		225	0E0EA09323
226	0868C6F545
		227	1D3D93A010
228	1454FAC979
		229	0101AF9C2C
230	0767C9FA4A

231	12329CAF1F
		232	045B0AC689
233	110E5F93DC
		234	176839F5BA
235	023D6CA0EF
		236	0B5405C986
237	1E01509CD3
		238	186736FAB5
239	0D3263AFE0
		240	045BF53989
241	110EA06CDC
		242	1768C60ABA
243	023D935FEF
		244	0B54FA3686
245	1E01AF63D3
		246	1867C905B5
247	0D329C50E0
		248	1B5B0A3976
249	0E0E5F6C23
		250	0868390A45
251	1D3D6C5F10
		252	1454053679
253	010150632C

254	076736054A
		255	123263501F

Table 1, sender unit identification sequence

Fig. 6 is the structure chart of OFDM symbol among Fig. 3.

As shown in the figure, the OFDM symbol is made of Cyclic Prefix (CP) and OFDM symbol body, and circulating prefix-length TCP is 51.2us, and OFDM symbol lengths TS is 409.6us.

Overlap mutually by protection interval (GD) between identification signal of transmitter among Fig. 3, synchronizing signal and the adjacent OFDM symbol, the protection length T GD of GD at interval is 2.4us.Between the adjacent-symbol, superpose after the afterbody GD of previous symbol and the weighting of the head GD of back symbol process window function, as shown in Figure 7.

Described window function expression formula is:

$w\left(t\right)=\left\{\begin{array}{cc}0.5+0.5\cos (\mathrm{\&pi;}+\mathrm{\&pi;t}/T_{\mathrm{GD}}),& 0\&le;t{\&le;\mathrm{<figure-callout\; id="1"\; label="T\; GD"\; filenames="A20061011391600431.png"\; state="\{\{state\}\}">T</figure-callout>}}_{\mathrm{GD}}\\ 1,& T_{\mathrm{GD}}<t<T-T_{\mathrm{GD}}\\ 0.5+0.5\cos (\mathrm{\&pi;}+\mathrm{\&pi;}(T-t)/T_{\mathrm{GD}}),& T-T_{\mathrm{GD}}\&le;t\&le;T\end{array}\right.$

Choosing as shown in Figure 8 of protection blank signal.For identification signal of transmitter, synchronizing signal and OFDM symbol, the value of T0 and T1 part sees Table 2.

Signal	T0(us)	T1(us)
			Identification signal of transmitter	25.6	10.4
Synchronizing signal	409.6	0
			The OFDM symbol	409.6	51.2

Table 2, protection blank signal list of values

Below each subsystem among Fig. 2 is elaborated.

Fig. 9 be byte interleaver device and RS (240, K) Bian Ma schematic diagram.

As shown in the figure, byte interleaver device is that MI is capable, the block interleaver of 240 row.The line number MI of byte interleaver device is by constellation mapping mode and the decision of LDPC code check, and is as shown in table 3:

	BPSK	QPSK	16QAM
					1/2 LDPC sign indicating number	MI＝36	MI＝72	MI＝144
3/4 LDPC sign indicating number	MI＝54	MI＝108	MI＝216

The list of values of table 3, byte interleaver device parameter MI

The RS sign indicating number adopt code length be 240 bytes RS (240, K) shortened code.(255, M) systematic code produces after by brachymemma this yard, and wherein, M=K+15, K are the byte number of information sequence in the code word, and the check word joint number is (240-K) simultaneously by original RS.(240, K) sign indicating number provides 4 kinds of patterns to RS, and the value of K is respectively K=240, K=224, K=192 and K=176 in these 4 kinds of patterns.

Each code element of RS sign indicating number is taken from territory GF (256), and its territory generator polynomial is p (x)=x ⁸+ x ⁴+ x ³+ x ²+ 1.

Shortened code RS (240, K) encode in the following way: at K input information byte (m ₀, m ₁..., m _K-1) 15 complete " 0 " bytes of preceding interpolation, be configured to original RS (255, M) list entries of systematic code (0 ... 0, m ₀, m ₁..., m _K-1), coding back generated codeword (0 ... 0, m ₀, m ₁..., m _K-1, p ₀, p ₁..., p _255-M-1), from code word, leave out the byte of being added again, promptly obtain the code word (m of the brachymemma RS sign indicating number of 240 bytes ₀, m ₁..., m _K-1, p ₀, p ₁..., p _255-M-1).

RS (240, K) expression formula of Ma generator polynomial is:

$g\left(x\right)=\underset{i=0}{\overset{240-K}{\mathrm{\&Sigma;}}}{g}_i{x}^i;$

The polynomial expression formula of information sequence of input is:

$m\left(x\right)=\underset{i=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{m}_i{x}^i;$

The polynomial expression formula of systematic code of output is:

$C\left(x\right)=\underset{i=0}{\overset{239}{\mathrm{\&Sigma;}}}{c}_i{x}^i=x^{240-K}m\left(x\right)+r\left(x\right),$ Wherein $r\left(x\right)=\frac{x^{240-K}\&CenterDot;m\left(x\right)}{g\left(x\right)}.$

The coefficient g of the generator polynomial expression formula of RS (240,224) _iFor:

i	g i	i	g i	i	g i	i	g i
								0	79	5	183	10	126	15	118
1	44	6	56	11	104	16	1
								2	81	7	17	12	31
3	100	8	232	13	103
								4	49	9	187	14	52

The coefficient g of the generator polynomial expression formula of RS (240,192) _iFor:

i	g i	i	g i	i	g i	i	g i
								0	228	14	12	27	109	40	32
1	231	15	160	28	176	41	157
								2	214	16	151	29	148	42	194
3	81	17	195	30	218	43	73
								4	113	18	170	31	21	44	195
6	204	19	150	32	161	45	218
								7	19	20	151	33	240	46	14
8	169	21	251	34	25	47	12
								9	10	22	218	35	15	48	122
10	244	23	245	36	71	49	1
								11	117	24	166	37	62

12	219	25	149	38	5
								13	130	26	183	39	17

The coefficient g of the generator polynomial expression formula of RS (240,176) _iFor:

i	g i	i	g i	i	g i	i	g i
								0	106	17	123	34	80	51	174
1	117	18	88	35	105	52	169
								2	43	19	44	36	44	53	136
3	201	20	149	37	72	54	23
								4	70	21	223	38	147	55	60
5	139	22	165	39	55	56	186
								6	47	23	36	40	60	57	63
7	64	24	127	41	85	58	198
								8	127	25	46	42	70	59	205
9	181	26	142	43	132	60	135
								10	48	27	212	44	229	61	171
11	25	28	233	45	230	62	40
								12	230	29	71	46	217	63	159
13	85	30	149	47	155	64	1
								14	31	31	88	48	38
15	157	32	165	49	112
								16	156	33	227	50	43

The method of coding and byte-interleaved is as follows: transmission data block is unit with the byte, and from left to right by row input block interleaver, every row MI byte is finished up to the K row.The RS coding is encoded by row, and check byte is filled to back (240-K) row.Data behind the coding are exported by row from left to right according to the order of input again, all finish up to 240 row.

Above-mentioned RS coding and byte-interleaved are that unit carries out with the physical logic channel, and the upper layer data bag of same physical logic channel is imported byte interleaver device successively and carried out byte-interleaved and RS coding.First byte of byte interleaver device the 0th row is defined as the start byte of byte interleaver device.The each output (MI * 240 bytes) of byte interleaver device always is mapped on the integer time slot and sends, and wherein the start byte of byte interleaver device is mapped in the starting point transmission of certain time slot.

According to the preferential principle that sends of high order bit, every byte is mapped as 8 bit streams through the transmission data after above-mentioned RS coding and the byte-interleaved, sends into the LDPC encoder.First byte of byte interleaver device the 0th row is defined as the start byte of byte interleaver device, and its highest order always is mapped in first bit of LDPC input bit piece.The configuration of LDPC coding is as shown in table 4:

Code check	The input block length	The output block length
			1/2	4608 bits	9216 bits
3/4	6912 bits	9216 bits

Table 4, the LDPC configuration of encoding

The LDPC coding is provided by check matrix H, and the generation method of H matrix is as follows:

1),

Code check matrix generation method

0 6 12 18 25 30

0 7 19 26 31 5664

0 8 13 20 32 8270

1 6 14 21 3085 8959

1 15 27 33 9128 9188

1 9 16 34 8485 9093

2 6 28 35 4156 7760

2 10 17 7335 7545 9138

2 11 22 5278 8728 8962

3 7 2510 4765 8637 8875

3 4653 4744 7541 9175 9198

3 23 2349 9012 9107 9168

4 7 29 5921 7774 8946

4 7224 8074 8339 8725 9212

4 4169 8650 8780 9023 9159

5 8 6638 8986 9064 9210

5 2107 7787 8655 9141 9171

5 24 5939 8507 8906 9173

Below for generating The cyclic program section of code check matrix:

for I＝1:18；

It is capable to get table the I, is designated as hexp;

for J＝1:256；

row＝(J-1)*18+I；

for K＝1:6；

The row of parity matrix is capable, column classifies non-0 element as;

end；

end；

end；

2), Code check matrix generation method

0	3	6	12	16	18	21	24	27	31	34	7494
												0	4	10	13	25	28	5233	6498	7018	8358	8805	9211
0	7	11	19	22	6729	6831	7913	8944	9013	9133	9184
												1	3	8	14	17	20	29	32	5000	5985	7189	7906
1	9	4612	5523	6456	7879	8487	8952	9081	9129	9164	9214
												1	5	23	26	33	35	7135	8525	8983	9015	9048	9154
2	3	30	3652	4067	5123	7808	7838	8231	8474	8791	9162
												2	35	3774	4310	6827	6917	8264	8416	8542	8834	9044	9089
2	15	631	1077	6256	7859	8069	8160	8657	8958	9094	9116

Below for generating The cyclic program section of code check matrix:

for I＝1:9；

It is capable to get table the I, is designated as hexp;

for J＝1:256；

row＝(J-1)*9+I；

for K＝1:12；

The capable column of row of parity matrix classifies non-0 element as;

end；

end；end；

Figure 10 is for carrying out the schematic diagram of Bit Interleave to process LDPC bit stream coded.

As shown in the figure, bit interleaver adopts 192 * 144 block interleaver.Binary sequence behind the LDPC coding is each row of write-in block interleaver successively in accordance with the order from top to bottom, until filling up whole interleaver, and reading from left to right again by leu.The output of bit interleaver is alignd with time slot, that is, first bit that transmits in each time slot always is defined as first bit of bit interleaver output.

Figure 11,12 and 13 is respectively BPSK constellation mapping figure, QPSK constellation mapping figure and 16QAM constellation mapping figure.Adopt BPSK, QPSK and the pairing power normalization factor of 16QAM constellation mapping be respectively 1/ , 1/ ,

Figure 14 is a pilot tone multiple connection mode schematic diagram of the subcarrier allocation of OFDM symbol being given data symbol, scattered pilot and continuous pilot.

As shown in the figure, oblique line is a continuous pilot signal partly, and black part is divided into discrete guide-frequency signal, the data symbol of white portion for obtaining through constellation mapping.Illustrated pilot tone multiple connection with data symbol, scattered pilot with continuous pilot multiple connection be in the same place, form the OFDM frequency domain symbol.Each OFDM symbol comprises 3076 subcarriers (0-3075), is designated as X (i), i=0, and 1 ... 3075.

Among Figure 15, continuous pilot uses the 0th, 20, and 32,72,88,128,146,154,156,216,220,250,296,313,314,330,388,406,410,470,472,480,498,538,554,594,606,627 subcarriers, totally 28.

The 20th, 32,72,88,128,146,154,156,470,472,480,498,538,554,594,606 totally 16 carriers carry 16 bit system information wherein, mapping relations are as shown in table 5, and system information is specifically explained as shown in table 6.All the other continuous pilot transmission " 0 ".

Bit	Adopt subcarrier number
		0	20
1	32

2	72
		3	88
4	128
		5	146
6	154
		7	156
8	470
		9	472
10	480
		11	498
12	538
		13	554
14	594
		15	606

Repeated encoding mode on table 5, the continuous pilot

Bit	Information

	0～5	Timeslot number
6			The byte interleaver device sync id
	7	Control logic channel change indication
8～15			Keep

Table 6, continuous pilot system for transmitting information

In the table 6 the concrete institute of each bit to comprise the information content as follows:

1), bit0～bit5 is current time slots number, span 0～39;

2), bit6 is the byte interleaver device sync id, this bit value is that to identify this time slot at 1 o'clock be the initial time slot of byte interleaver device;

3), bit7 is control logic channel change indication, it adopts the mode indicating terminal control logic channel configuration information change of differential modulation.Described differential mode is as follows: what suppose that previous frame bit7 transmits is a (0 or 1), and system's control channel configuration information will change at next frame, then transmits a and keep in this frame, changes up to take place next time.

4), bit8～bit15 keeps.

Continuous pilot with 0 → / 2+ / 2j, 1 →- / 2- / mode of 2j is mapped on the subcarrier.The symbol that the identical continuous subcarrier point of different OFDM symbols upward transmits in the same time slot is identical.

Note n is the numbering of OFDM symbol in each time slot, 0≤n≤52; M is the subcarrier number of scattered pilot correspondence in each OFDM symbol, and then the m value is as follows:

if mod(n，2)＝＝0

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,38\\ 8p+3,& p=\mathrm{39,40,41},\&CenterDot;\&CenterDot;\&CenterDot;,77\end{array}\right.$

if mod(n，2)＝＝1

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1,2},\&CenterDot;\&CenterDot;\&CenterDot;,38\\ 8p+7,& p=\mathrm{39,40,41},\&CenterDot;\&CenterDot;\&CenterDot;,77\end{array}\right.$

Scattered pilot all is changed to 1+0j.

Among Figure 14, press the front and back order mapping (enum) data signal of subcarrier, OFDM symbol.In 27666 data subcarriers in each time slot, preceding 27648 subcarriers are used to carry the complex symbol of character interleaver output, and last 18 symbols mend 0.

All symbols on the time-frequency grid shown in Figure 14 (effectively subcarrier) comprise data subcarrier, scattered pilot and continuous pilot etc., all by a multiple pseudo random sequence p _c(i) scrambler.Described multiple pseudo random sequence P _c(i) generating mode is as follows:

$P_c\left(i\right)=\frac{\sqrt{2}}{2}[(1-{2S}_i\left(i\right))+j(1-{2S}_q\left(i\right))],$

Wherein, S _i(i) and S _q(i) be binary pseudo-random sequence (PRBS).

Figure 15 is the schematic diagram of PRBS generation method.

As shown in the figure, the generator polynomial of PRBS is: x ¹²+ x ¹¹+ x ⁸+ x ⁶+ 1, corresponding with illustrated shift register structure.The initial value of shift register determines that by the scrambler pattern its corresponding relation is as follows:

1), the scrambler pattern 0: initial value 0,000 0,000 0001

2), the scrambler pattern 1: initial value 0,000 1,001 0011

3), the scrambler pattern 2: initial value 0,000 0,100 1100

4), scrambler mode 3: initial value 0,010 1,011 0011

5), the scrambler pattern 4: initial value 0,111 0,100 0100

6), the scrambler pattern 5: initial value 0,000 0,100 1100

7), the scrambler pattern 6: initial value 0,001 0,110 1101

8), scrambler mode 7: initial value 0,010 1,011 0011

PRBS resets in each time slot beginning, and all time slots are all by identical pattern scrambler.

This scrambler passes through complex symbol on effective subcarrier and multiple pseudo random sequence p _c(i) carry out complex multiplication and realize that the expression formula of described scrambler is:

Y _n(i)＝X _n(i)×p _c(n×628+i)，0≤i≤627，0≤n≤52

Wherein, x _n(i) be the i on n OFDM symbol of each time slot effective subcarrier before the scrambler, Y _n(i) be effective subcarrier behind the scrambler.

Figure 16 is an OFDM symbol sub-carrier structure schematic diagram.

OFDM subcarrier X (i) behind above-mentioned insertion pilot tone and the scrambler, i=0,1 ..., 1023 through IFFT conversion generation OFDM time-domain symbol.The IFFT mapping mode is as follows:

$y\left(t\right)=\frac{1}{\sqrt{1024}}\underset{n=0}{\overset{1023}{\mathrm{\&Sigma;}}}Y\left(n\right){\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="A20061011391600431.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ 0≤t≤409.6us，f _s＝2.5MHz

Wherein,

$Y\left(n\right)=\left\{\begin{array}{cc}X(n-1),& 1\&le;n\&le;314\\ X(n-396),& 710\&le;n\&le;1023\\ 0,& n=0\mathrm{or}315\&le;n\&le;709\end{array}\right.$

OFDM symbol through the IFFT conversion is described according to Fig. 6, adds Cyclic Prefix (CP), forms the time domain OFDM symbol.

OFDM symbol after the modulation according to the described frame structure of Fig. 3, is formed time slot after adding protection interval, synchronizing signal, the transmitter identification signal successively.Again 40 time slots are connected to form the physical layer signal frame.

The time domain forming filter that native system adopts is the FIR filter, satisfies ripple decay＜1dB in the signal bandwidth, and bandwidth decays outward＞40dBc.Band bandwidth is 2MHz and digital audio broadcasting bandwidth compatibility.The systematic sampling rate is 2.5MHz, and the signal bandwidth of every channel is 1.536MHz.

The upper layer data stream of native system can adopt comprise H.264, video flowing such as AVS, MPEG-2, MPEG-4, the data format of audio stream such as AC-3, AAC and other numerous types of data.Various types of broadcast datas that can comprise single medium (for example video frequency source coding, text) and multimedia (mixing of audio frequency, video, text and data) to the data coding.

The present invention is not limited to above-mentioned particular implementation example; do not deviating under spirit of the present invention and the real situation thereof; skilled personnel can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong within the claims protection range of the present invention.

Claims (41)

1, a kind of digital information transmission method of kind of multicarrier digital mobile multimedia broadcast system is characterized in that may further comprise the steps:

By the physical logic channel upper layer data stream is carried out RS coding and byte-interleaved by RS coding and byte interleaver device, wherein, the line number of described byte interleaver device is by constellation mapping mode and the decision of LDPC code check;

To carry out the LDPC coding through the data of byte-interleaved, obtain Bit data by the LDPC encoder;

By bit interleaver the Bit data that obtains through the LDPC coding is carried out Bit Interleave;

By constellation mapper the data through Bit Interleave are carried out constellation mapping;

By the frequency domain multiplexer OFDM frequency domain symbol is formed in the data symbol multiple connection of scattered pilot, the continuous pilot that includes system information and process constellation mapping together;

By scrambler the above-mentioned OFDM frequency domain symbol that obtains through multiple connection is carried out scrambler;

By producing the OFDM time-domain symbol after the frequency domain symbol process IFFT conversion of IFFT converter with above-mentioned process scrambler;

By the time domain framer with above-mentioned time domain OFDM symbol through after insertion frame head and forming time slot, connect to form the physical layer signal frame;

Above-mentioned physical layer signal frame is carried out launching behind low-pass filtering and the quadrature up-conversion.

2, digital information transmission method as claimed in claim 1 is characterized in that, this method is used any 2MHz bandwidth in the wireless channel, and and digital audio broadcasting bandwidth compatibility.

3, digital information transmission method as claimed in claim 1 is characterized in that, sample rate is 2.5MHz in this method, and the signal bandwidth of every channel is 1.536MHz.

4, digital information transmission method as claimed in claim 1 is characterized in that, this upper layer data stream be comprise H.264, AVS, MPEG-2, the video flowing of MPEG-4 and the data flow that comprises the audio stream of AC-3, AAC.

5, digital information transmission method as claimed in claim 1 is characterized in that, this method is mainly used in to realize moving and receives.

6, digital information transmission method as claimed in claim 1 is characterized in that, this method is supported single frequency network and multiple frequency network, MFN networking model.

7, digital information transmission method as claimed in claim 1 is characterized in that, this method is selected corresponding transmission mode and parameter according to wire data type and network environment.

8, digital information transmission method as claimed in claim 1 is characterized in that, this method is supported the mixed transmission modes of numerous types of data.

9, digital information transmission method as claimed in claim 1 is characterized in that, this physical logic channel is divided into control logic channel and service logical channels.

10, digital information transmission method as claimed in claim 1 is characterized in that, the signal of this method is made of frame.

11, digital information transmission method as claimed in claim 10 is characterized in that, the length of described frame is 1 second.

12, digital information transmission method as claimed in claim 10 is characterized in that, described each frame comprises that 40 length are 25 milliseconds time slot.

13, digital information transmission method as claimed in claim 1 is characterized in that, described physical logic channel transmits in 1 or a plurality of time slot.

14, digital information transmission method as claimed in claim 12 is characterized in that, described time slot comprises beacon and OFDM symbol.

15, digital information transmission method as claimed in claim 12 is characterized in that, described time slot comprises 1 beacon and 53 OFDM symbols.

16, digital information transmission method as claimed in claim 14 is characterized in that, described beacon comprises sender unit identification and synchronizing sequence.

17, digital information transmission method as claimed in claim 14 is characterized in that, described beacon comprises 1 sender unit identification and 2 identical synchronizing sequences.

18, digital information transmission method as claimed in claim 16 is characterized in that, described identification signal of transmitter is carried out getting through the circulation continuation after BPSK mapping and the IFFT conversion by the frequency domain random sequence successively again.

19, digital information transmission method as claimed in claim 16 is characterized in that, described identification signal of transmitter carries out BPSK mapping by 37 frequency domain random sequence and through after 64 the IFFT conversion, again continuation 26 o'clock to 90 o'clock and obtaining.

20, digital information transmission method as claimed in claim 16 is characterized in that, described synchronizing sequence by intercepting frequency domain random sequence after, carry out BPSK and IFFT conversion successively and obtain.

21, digital information transmission method as claimed in claim 20 is characterized in that, described frequency domain random sequence is produced by linear feedback shift register, and the initial value of this shift register is 01110101101, generator polynomial is: x ¹¹+ x ⁹+ 1.

22, digital information transmission method as claimed in claim 21 is characterized in that, described frequency domain random sequence is that BPSK shines upon and 512 IFFT conversion get by carrying out successively intercept at 314 from the sequence that described shift register produced after.

23, digital information transmission method as claimed in claim 16 is characterized in that, described sender unit identification, synchronizing sequence and OFDM intersymbol adopt the protection of band window function to overlap mutually at interval, and the expression formula of described window function is:

$w(t=\left\{\begin{array}{cc}0.5+0.5\cos (\mathrm{\&pi;}+\mathrm{\&pi;t}/T_{\mathrm{GD}}),& 0\&le;t\&le;T_{\mathrm{GD}}\\ 1,& T_{\mathrm{GD}}<t<T-T_{\mathrm{GD}}\\ 0.5+0.5\cos (\mathrm{\&pi;}+\mathrm{\&pi;}(T-t)/T_{\mathrm{GD}}),& T-T_{\mathrm{GD}}\&le;t\&le;T\end{array}\right.,$ Wherein, t is a time variable, and T is a constant, T _GDBe described protection length at interval.

24, digital information transmission method as claimed in claim 23 is characterized in that, described protection length at interval is 6 points.

25, digital information transmission method as claimed in claim 14 is characterized in that, described OFDM symbol is made of OFDM symbol body and Cyclic Prefix.

26, digital information transmission method as claimed in claim 25 is characterized in that, the length of described OFDM symbol body is 1024 points, and the length of Cyclic Prefix is 128 points.

27, digital information transmission method as claimed in claim 1 is characterized in that, described RS coding be by original RS (255, M) RS that produces after by brachymemma of systematic code (240, K) shortened code, wherein, M=K+15, K and M are that information bit is long.

28, digital information transmission method as claimed in claim 27 is characterized in that, (255, M) each code element of systematic code is taken from territory GF (256) to described RS, and the generator polynomial in this territory is p (x)=x ⁸+ x ⁴+ x ³+ x ²+ 1.

29, digital information transmission method as claimed in claim 27 is characterized in that, (240, K) sign indicating number comprises 4 kinds of patterns to described RS, and the value of K is respectively K=240, K=224, K=192 and K=176 in these 4 kinds of patterns.

30, digital information transmission method as claimed in claim 27 is characterized in that, (240, K) expression formula of Ma generator polynomial is described RS $g\left(x\right)=\underset{i=0}{\overset{240-K}{\mathrm{\&Sigma;}}}{g}_i{x}^i.$

31, digital information transmission method as claimed in claim 29 is characterized in that, when K=224, and the coefficient g of the generator polynomial expression formula of RS (240,224) _iFor: I g _i I g _i i g _i i g _i 0 79 5 183 10 126 15 118 1 44 6 56 11 104 16 1 2 81 7 17 12 31 3 100 8 232 13 103 4 49 9 187 14 52

When K=192, the coefficient g of the generator polynomial expression formula of RS (240,192) _iFor: I g _i I g _i i g _i i g _i 0 228 14 12 27 109 40 32 1 231 15 160 28 176 41 157 2 214 16 151 29 148 42 194 3 81 17 195 30 218 43 73 4 113 18 170 31 21 44 195 6 204 19 150 32 161 45 218 7 19 20 151 33 240 46 14 8 169 21 251 34 25 47 12 9 10 22 218 35 15 48 122 10 244 23 245 36 71 49 1 11 117 24 166 37 62 12 219 25 149 38 5 13 130 26 183 39 17

When K=176, the coefficient g of the generator polynomial expression formula of RS (240,176) _iFor: I g _i I g _i i g _i i g _i 0 106 17 123 34 80 51 174 1 117 18 88 35 105 52 169 2 43 19 44 36 44 53 136 3 201 20 149 37 72 54 23 4 70 21 223 38 147 55 60 5 139 22 165 39 55 56 186 6 47 23 36 40 60 57 63 7 64 24 127 41 85 58 198 8 127 25 46 42 70 59 205 9 181 26 142 43 132 60 135 10 48 27 212 44 229 61 171 11 25 28 233 45 230 62 40 12 230 29 71 46 217 63 159 13 85 30 149 47 155 64 1 14 31 31 88 48 38 15 157 32 165 49 112 16 156 33 227 50 43

32, digital information transmission method as claimed in claim 1, it is characterized in that, described upper layer data stream is unit with the byte, from left to right by row input RS coding and byte interleaver device, wherein, the RS coding is encoded by row, and the starting point that the start byte of byte interleaver device is mapped in certain time slot sends.

33, digital information transmission method as claimed in claim 1 is characterized in that, the output block length behind the described LDPC coding is 9216 bits, and code check is 1/2 and 3/4;

Wherein,

It is at first, to set up following data matrix that code check matrix generates step:

0 6 12 18 25 30

0 7 19 26 315 664

0 8 13 20 32 8270

1 6 14 21 3085 8959

1 15 27 33 9128 9188

1 9 16 34 8485 9093

2 6 28 35 4156 7760

2 10 17 7335 7545 9138

2 11 22 5278 8728 8962

3 7 2510 4765 8637 8875

3 4653 4744 7541 9175 9198

3 23 2349 9012 9107 9168

4 7 29 5921 7774 8946

4 7224 8074 8339 8725 9212

4 4169 8650 8780 9023 9159

5 8 6638 8986 9064 9210

5 2107 7787 8655 9141 9171

5 24 5939 8507 8906 9173

Secondly, setting up loop index is first circulation of I, and wherein the value of I is 1 to 18, get table the I line data composition sequence and be designated as hexp, be nested with second circulation that loop index is J in first circulation, wherein the value of J is 1 to 256, subsequently according to formula row=[(J-1) * 18+I] obtain The capable variable row of code check matrix, nested loop index is the 3rd circulation of K under the described capable variable row of second circulation then, wherein the value of K is 1 to 6, numeration is hexp (K) according to K the data of sequences h exp, then according to formula column=Mod[( hexp (K)/36 +J-1), 256] * and 36+Mod[hexp (K), 36]+1 acquisition is described

Code check matrix;

Described It is at first, to set up following data matrix that code check matrix generates step: 0 3 6 12 16 18 21 24 27 31 34 7494 0 4 10 13 25 28 5233 6498 7018 8358 8805 9211 0 7 11 19 22 6729 6831 7913 8944 9013 9133 9184 1 3 8 14 17 20 29 32 5000 5985 7189 7906 1 9 4612 5523 6456 7879 8487 8952 9081 9129 9164 9214 1 5 23 26 33 35 7135 8525 8983 9015 9048 9154 2 3 30 3652 4067 5123 7808 7838 8231 8474 8791 9162 2 35 3774 4310 6827 6917 8264 8416 8542 8834 9044 9089 2 15 631 1077 6256 7859 8069 8160 8657 8958 9094 9116

Secondly, setting up loop index is first circulation of I, and wherein the value of I is 1 to 9, get table the I line data composition sequence and be designated as hexp, be nested with second circulation that loop index is J in first circulation, wherein the value of J is 1 to 256, then according to formula row=[(J-1) * 9+I] obtain

The capable variable row of code check matrix; Nested loop index is the 3rd circulation of K under the described capable variable row of second circulation, wherein the value of K is 1 to 12, numeration is hexp (K) according to K the data of sequences h exp, then according to formula column=Mod[( hexp (K)/36 +J-1), 256] * and 36+Mod[hexp (K), 36]+1 acquisition is described

Code check matrix.

34, digital information transmission method as claimed in claim 1 is characterized in that, described bit interleaver adopts 192 * 144 block interleaver; Write each row of described block interleaver in accordance with the order from top to bottom successively from the encode Bit data of its output of LDPC, until filling up whole block interleaver, reading from left to right again by leu, wherein the output of bit interleaver is alignd with time slot.

35, digital information transmission method as claimed in claim 1 is characterized in that, described constellation mapping adopts the wherein a kind of of the mapping mode that comprises BPSK, QPSK, 16QAM.

36, digital information transmission method as claimed in claim 1, it is characterized in that, described frequency domain symbol generates in the step, with 78 scattered pilots, 28 continuous pilot, the multiple connection of 522 data subcarriers together, becomes 628 effective subcarriers in each OFDM symbol.

37, digital information transmission method as claimed in claim 36 is characterized in that, described 28 continuous pilot use in described 628 effective subcarriers the 0th, 20,32,72,88,128,146,154,156,216,220,250,296,313,314,330,388,406,410,470,472,480,498,538,554,594,606,627 subcarriers, and therein the 20th, 32,72,88,128,146,154,156,470,472,480,498,538,554,594,606 carry 16 bit system information in totally 16 subcarriers, and described system information comprises that length is the timeslot number of 6 bits, length is the byte interleaver device sync id of 1 bit, length is that the control logic channel change indication and the length of 1 bit is the reserved word of 8 bits; Described continuous pilot is with 0 → /2+ /2j, 1 →-mode of /2-/2j is mapped on the subcarrier, and wherein, to go up the symbol that transmits identical for the identical continuous subcarrier point of different OFDM symbols in the same time slot.

38, digital information transmission method as claimed in claim 36 is characterized in that, when OFDM symbol in each time slot be numbered n the time, the subcarrier number m value of scattered pilot correspondence is in the OFDM symbol:

$\mathrm{if}\mathrm{mod}(n,2)==0$

$m=\left\{\begin{array}{cc}8p+1,& p=\mathrm{0,1,2},\&hellip;,38\\ 8p+3,& p=\mathrm{39,40,41},\&hellip;,77\end{array}\right.$

$\mathrm{if}\mathrm{mod}(n,2)==1$

$m=\left\{\begin{array}{cc}8p+5,& p=\mathrm{0,1,2},\&hellip;,38\\ 8p+7,& p=\mathrm{39,40,41},\&hellip;,77\end{array}\right.$

Scattered pilot all is changed to 1+0j.

39, digital information transmission method as claimed in claim 1 is characterized in that, the generator polynomial of the described pseudo random sequence in the described scrambler step is x ¹²+ x ¹¹+ x ⁸+ x ⁶+ 1; Described scrambler is divided into 8 kinds of patterns, and corresponding register initial value is respectively:

1), the scrambler pattern 0: initial value 0,000 0,000 0001

2), the scrambler pattern 1: initial value 0,000 1,001 0011

3), the scrambler pattern 2: initial value 0,000 0,100 1100

4), scrambler mode 3: initial value 0,010 1,011 0011

5), the scrambler pattern 4: initial value 0,111 0,100 0100

6), the scrambler pattern 5: initial value 0,000 0,100 1100

7), the scrambler pattern 6: initial value 0,001 0,110 1101

8), scrambler mode 7: initial value 0,010 1,011 0011

Described pseudo random sequence is reset in the beginning of each time slot, and all time slots are all by identical pattern scrambler.

40, digital information transmission method as claimed in claim 1 is characterized in that, described IFFT shift step is to carry out 1024 IFFT conversion after being placed on 628 effective subcarriers on the 1st～314 and the 710th～1023 subcarrier of 1024 subcarriers.

41, digital information transmission method as claimed in claim 1; it is characterized in that; described time domain framing step is to form time slot after the OFDM symbol after the modulation is added protection interval, synchronizing signal, transmitter identification signal successively, again 40 time slots is connected to form the physical layer signal frame.

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