CN104486033A - Downlink multimode channel coding system and method based on C-RAN platform - Google Patents

Abstract

The invention provides a downlink multimode channel coding system and method based on a C-RAN platform. The method comprises the steps of multi-mode high-speed CRC coding and downlink multi-mode channel coding, wherein the downlink multi-mode channel coding adopts convolutional encoding and Turbo coding according to different standards. The system and the method have the advantages that under the three major standard frameworks of GSM/TD-SCDMA/LTE, the resource reasonable sharing and integral optimization are adopted, and the scheme of carrying out downlink channel coding switching among three standards according to mode conversion signals under the uninterruptible power condition is designed. According to the scheme, the multi-mode channel coding adopts 8-bit parallel high-speed algorithms, the multi-mode can be realized, in addition, the calculation speed is 9 times faster than the traditional speed, short resources in the C-RAN framework can be saved, the time delay is reduced, and the system performance is improved.

Description

A kind of descending multimode channel coded system based on C-RAN platform and method

Technical field

The invention belongs to wireless communication technology field, relate to mobile communication and coding techniques, the continuous TURP be particularly useful under the large standard card cage of GSM, TD-SCDMA, LTE tri-under C-RAN platform between down channel coding changes.

Background technology

Due to reasons such as time-varying fading channels, interference and noises, there is the error rate in wireless signal in wireless transmission process.In a wireless communication system, channel coding schemes adopts error correction coding mechanism to ensure the reliability transmitted usually.Convolution code as its member's code, and is introduced interleaver by Turbo code, reduces correlation.Because Turbo code can meet the Stochastic Conditions of Shannon Channel coding theory, use iterative encoding scheme, performance in theory can close to shannon limit.Its superior resist miscode ability, receives and pays close attention to widely.At present, Turbo code is widely used in the mobile communication system such as 3G/4G.

CRC coding is a kind of conventional error-detecting code, the CRC coding of multiple different length is all employ, to ensure the correctness of information transmission under various transformat in the agreement of each versions such as Wideband Code Division Multiple Access (WCDMA)/Time Division-Synchronous Code Division Multiple Access/long evolving system (WCDMA/TD-SCDMA/LTE).

Always have 18 kinds of CRC in the large standard of GSM, TD-SCDMA, LTE tri-, chnnel coding is all with convolution code or the Turbo code closely similar with convolution code.Three substandard encryption algorithms are substantially the same, and the resource that difference just consumes is not etc.Calculate if 18 kinds of CRC are separately carried out or by the separately process of three substandard cataloged procedures, greatly will waste hardware resource.The high-speed transfer that will reach at least 100M/s because LTE is descending, traditional single-bit generating algorithm, computation delay is comparatively large, cannot meet the high-speed demand of LTE system.

China Mobile runs GSM, TD-SCDMA, TD-LTE tri-communication networks at present simultaneously.The Traffic Channel (TCH) of the mainly GSM of transmission data, the DSCH Downlink Shared Channel (DSCH) of TD-SCDMA, with the Physical Downlink Shared Channel (PDSCH) of TD-LTE, to the process of related data, the calculating that the system that occupies is a large amount of and storage resources.Therefore China Mobile proposes new wireless access planar network architecture C-RAN, and it is a kind of centralized cloud framework the Technology of Wireless Access Networks.This technology support multimode demand while, system saving resource of can also trying one's best when not affecting function.

Following Patents document is found: rapid cyclic redundancy check encoding method and device (CN200910085524) through retrieval, comprise generator polynomial of being encoded by cyclic redundancy check (CRC) to map and generate r+1 rank transfer matrix, wherein r is for generating polynomial most high reps; Zero input transfer matrix and nought state transfer matrix of CRC coding is obtained by r rank transfer matrix and r × 1 column matrix; Before incoming bit stream, add room bit, the number of bits of adding the incoming bit stream after the bit of room is the integral multiple of concurrent operation bit wide; According to the incoming bit stream after zero input, nought state transfer matrix and interpolation room bit, obtain CRC coding checkout sequence.The program can carry out CRC coding to multiple input bit in a clock.But LTE two-way CRC can not be completed encode simultaneously, and can not the CRC of simultaneously compatible TD-SCDMA and GSM encode, single mode form can only be supported, and do not match with chnnel coding, the matrix operation complexity used is high, takies hardware resource many, is unfavorable for igh-speed wire-rod production line.

Parallel Turbo coder (CN 200910201488), comprise parallel interleaver, comprise interleaving address generator and alternately serve as two interleaver buffer of reading and writing buffer, each interleaver buffer includes the multiple memory cell for storing corresponding bits, under the control of the control signal that these memory cell produce for corresponding bits at described interleaving address generator, export parallel system bit stream and parallel interleaved bitstream.Afterwards parallel encoding is carried out to parallel system bit stream, produce the first and second Parity Check Bits streams.This Turbo encoder there is higher throughput and the stand-by period short.Although the interleaver in this encoder only has plus and minus calculation device, can calculation step is more, also exists and ask modular arithmetic, therefore clock cycle can not complete the computing of a multidigit address, and needs a large amount of memory space.

A kind of Turbo code coding method and encoder (CN 201210216116), comprise the preset parameter received for three parameters and correspondence calculating interleaving address; The data of the block to be encoded of buffer memory are read according to described interleaving address; Export by the data of the block to be encoded of the buffer memory of order reading with after carrying out Recursive Systematic Convolutional coding according to the data of the block to be encoded of interleaving address reading.Provide a kind of Turbo code encoder, the Turbo code encoded question of the not reciprocity situation of input and output speed can be solved.But interleaver calculating process in this encoder is complicated, and exists and ask modular arithmetic, the computing of a multidigit address can not be completed a clock cycle.

In addition, encoder mentioned in CN200910201488 and CN201210216116 can only support that the single mode Turbo of LTE encode, can not the Turbo coding of compatible TD-SCDMA and the convolutional encoding of GSM, does not encode with CRC and matches.

Larger difference is had by the technology contents and present patent application of analyzing above patent application.

Summary of the invention

For above deficiency of the prior art, the descending multimode channel coded system based on C-RAN platform that the object of the present invention is to provide the two-forty under a kind of multi-mode, high systematic function, resource overhead little and method, technical scheme of the present invention is as follows: a kind of descending multimode channel coded system based on C-RAN platform, and it comprises cyclic redundancy check (CRC) coding unit: for carrying out cyclic redundancy check (CRC) coding to 8 parallel-by-bit input data to be encoded;

Buffer unit: the code signal for exporting cyclic redundancy check (CRC) coding unit stores:

Multimode interleave unit: the mode control signal for sending according to top level control unit selects corresponding interleaving mode to interweave to the data in buffer unit, specifically comprise: when adopting LTE pattern, adopt QPP interleaver, the information bit of definition to input according to QPP interleaver in 3GPP TS 36.212 agreement interweaves; When adopting TD-SCDMA pattern, adopting area to change tachometric method, storing the interleaving address table of often kind of block in advance, complete the intertexture often walking 8 bits in the mode of meter reading; When adopting GSM mode, form information bit by front 50 bits of every block and 132 bits, add parity bits and tail bit totally 189 bits carry out interleave address;

Coding unit: for the output signal of encoding after described CRC coding and the interleaved signal exported through described multimode interleave unit thereof, data carry out parallel input with 8, and described coding unit decides the mode of encoding by mode adjudging;

Coding unit carries out convolutional encoding and Turbo coding respectively according to different patterns.Under LTE and TD-SCDMA pattern, adopt Turbo coding, its framework is made up of 3 bit registers, coding staff same pattern owned by France.Adopt convolutional encoding under GSM mode, its framework is made up of 4 bit registers.In order to realize multimode, original that two-way encoder as Turbo code coding being carried out Curve guide impeller, becomes 4 calculating from 3 calculating.

Top level control unit: for carrying out top level control to cyclic redundancy check (CRC) coding unit, buffer unit, multimode interleave unit, parallel/serial converting unit, comprises model selection control, block size controls and enable signal controls; Chnnel coding in descending multimode chnnel coding is divided into convolutional encoding and Turbo coding according to different patterns.

Parallel/serial converting unit: carry out output encoder sequence after parallel/serial conversion for finally delivering to buffer to the output sequence of CRC coding unit or its information bit after the interleaved sequence that described multimode interleave unit exports is encoded.

Based on a descending multimode channel coding method for C-RAN platform, it comprises the following steps:

201, cyclic redundancy check (CRC) coding unit receives input information data, first judge that whether input message sequence length be the multiple of 8, if the multiple of 8, then directly carry out step 202, otherwise add before sequence 0 bit make data block length be 8 multiple, carry out multimode high speed CRC and encode;

202, cyclic redundancy check (CRC) calculating is carried out using 8 bits as a unit, need before calculating to encode according to the different pattern of top level control unit, CRC calculator generator polynomial needed for selection, then calculates final coding result according to the information sequence of CRC generator polynomial and input;

203, buffer unit is stored into the CRC coding result obtained in step 202, and according to the mode control signal control model selector switch of top level control unit, the data in buffer unit are interweaved, specifically comprise: when adopting LTE pattern, adopt QPP interleaver, the information bit of definition to input according to QPP interleaver in 3GPP TS 36.212 agreement interweaves; When adopting TD-SCDMA pattern, adopting area to change tachometric method, storing the interleaving address table of often kind of block in advance, complete the intertexture often walking 8 bits in the mode of meter reading; When adopting GSM mode, form information bit by front 50 bits of every block and 132 bits, add parity bits and tail bit totally 189 bits carry out interleave address;

204, after the multimode interleaving steps in step 203, the output signal after being encoded by CRC and the interleaved signal through the output of multimode intertexture thereof are encoded, and concrete steps are: under GSM mode, and switch is connected with next branch road, adopt convolutional encoding under this pattern; Under LTE/TD-SCDMA pattern, switch is connected with a upper branch road, input coding device 1 and 2 be interleaved sequence and non-interleaved sequence respectively; Under LTE and TD-SCDMA pattern, adopt Turbo coding;

205, buffer is finally delivered to the output sequence of CRC coding unit or its information bit after the interleaved sequence that described multimode interleave unit exports is encoded and carry out output encoder sequence after parallel/serial conversion, judge that whether output sequence length be the multiple of 8, if not, before sequence, then add 0 bit obtain the sequence that length is the multiple of 8, otherwise do not process.

Further, the LTE in step 203 adopts CRC:CRC24A, CRC24B, CRC16, CRC8 of 4 kinds of forms; TD-SCDMA also adopts CRC:CRC24, CRC16, CRC12, CRC8 of 4 kinds of forms,

GSM adopts CRC:CRC40, CRC16, CRC14, CRC12, CRC10, CRC8A, CRC8B, CRC6, CRC3 of 9 kinds of forms.

Advantage of the present invention and beneficial effect as follows:

1, the C-RAN platform that the solution of the present invention adopts be based on focusing on, the green wireless access planar network architecture of collaboration type radio, real-time cloud computing architecture, decrease base station machine room quantity, reduce power consumption, adopt Collaborative, Intel Virtualization Technology simultaneously, realize resource-sharing, dynamic dispatching, improve spectrum efficiency, reduce costs, the operation of high bandwidth and high flexibility is provided.

2. CRC wherein encode calculating can 8 the CRC codings of parallel processing simultaneously, computational speed is 8 times of traditional scheme, improves data throughout.In the process of carrying out CRC coding, when calculating CRC24A and CRC24B of LTE, abandoning traditional first calculating CRC24A, then having calculated the step of CRC24B, being designed to two-way parallel synchronous CRC and calculating, reduce delay.When the CRC being switched to TD-SCDMA or GSM calculates, also in a module, two paths of signals can be calculated simultaneously.Reach the object supporting various criterion in identical resource.

3, the program designs the encoding scheme for multimode down channel, reduces the consumption of resource, and have feasibility on hardware.Simultaneously multimode down channel encoding scheme can be faced the reality the complex situations that middle multiple standards coexists flexibly, meets the demands such as system upgrade.And in the mode of resource-sharing, decrease the waste that resources idle causes.

Accompanying drawing explanation

Fig. 1 is according to structural framing figure of the present invention;

Fig. 2 is the overall construction drawing that multimode CRC of the present invention encodes;

Fig. 3 is multimode down channel coded system structure chart of the present invention;

Fig. 4 is constituent encoder structure chart of the present invention.

Embodiment

The invention will be further elaborated to provide an infinite embodiment below in conjunction with accompanying drawing.But should be appreciated that, these describe just example, and do not really want to limit the scope of the invention.In addition, in the following description, the description to known features and technology is eliminated, to avoid unnecessarily obscuring concept of the present invention.

As shown in Figure 1, first carry out multimode high speed CRC and encode, first judge that whether input message sequence length be the multiple of 8, if the multiple of 8, then directly carry out step 2, otherwise add before sequence 0 bit make data block length be 8 multiple.

Carry out CRC calculating using 8 bits as a unit, before calculating, need the CRC generator polynomial needed for different model selections, then calculate final result according to the information sequence of CRC generator polynomial and input.Based on a descending multimode channel coding method for C-RAN platform, it comprises the following steps:

201, cyclic redundancy check (CRC) coding unit receives input information data, first judge that whether input message sequence length be the multiple of 8, if the multiple of 8, then directly carry out step 202, otherwise add before sequence 0 bit make data block length be 8 multiple, carry out multimode high speed CRC and encode;

202, cyclic redundancy check (CRC) calculating is carried out using 8 bits as a unit, need before calculating to encode according to the different pattern of top level control unit, CRC calculator generator polynomial needed for selection, then calculates final coding result according to the information sequence of CRC generator polynomial and input;

203, buffer unit is stored into the CRC coding result obtained in step 202, and according to the mode control signal control model selector switch of top level control unit, the data in buffer unit are interweaved, specifically comprise: when adopting LTE pattern, adopt QPP interleaver, the information bit of definition to input according to QPP interleaver in 3GPP TS 36.212 agreement interweaves; When adopting TD-SCDMA pattern, adopting area to change tachometric method, storing the interleaving address table of often kind of block in advance, complete the intertexture often walking 8 bits in the mode of meter reading; When adopting GSM mode, form information bit by front 50 bits of every block and 132 bits, add parity bits and tail bit totally 189 bits carry out interleave address;

204, after the multimode interleaving steps in step 203, the output signal after being encoded by CRC and the interleaved signal through the output of multimode intertexture thereof are encoded, and concrete steps are: under GSM mode, and switch is connected with next branch road, adopt convolutional encoding under this pattern; Under LTE/TD-SCDMA pattern, switch is connected with a upper branch road, input coding device 1 and 2 be interleaved sequence and non-interleaved sequence respectively; Under LTE and TD-SCDMA pattern, adopt Turbo coding;

205, buffer is finally delivered to the output sequence of CRC coding unit or its information bit after the interleaved sequence that described multimode interleave unit exports is encoded and carry out output encoder sequence after parallel/serial conversion, judge that whether output sequence length be the multiple of 8, if not, before sequence, then add 0 bit obtain the sequence that length is the multiple of 8, otherwise do not process.

Fig. 2 is multimode CRC coding structure schematic diagram of the present invention.As shown in Figure 1, this coding structure is made up of two common mode CRC calculators.Before encoding, corresponding CRC generator polynomial is selected according to different system patterns.Wherein LTE adopts CRC:CRC24A, CRC24B, CRC16, CRC8 of 4 kinds of forms.Its generator polynomial:

g _CRC24A(D)＝D ²⁴+D ²³+D ¹⁸+D ¹⁷+D ¹⁴+D ¹¹+D ¹⁰+D ⁷+D ⁶+D ⁵+D ⁴+D ³+D+1

g _CRC24B(D)＝D ²⁴+D ²³+D ⁶+D ⁵+D+1

g _CRC16(D)＝D ¹⁶+D ¹²+D ⁵+1

g _CRC8(D)＝D ⁸+D ⁷+D ⁴+D ³+D+1

TD-SCDMA also adopts CRC:CRC24, CRC16, CRC12, CRC8 of 4 kinds of forms, and its generator polynomial is as follows:

g _CRC24B(D)＝D ²⁴+D ²³+D ⁶+D ⁵+D+1

g _CRC16(D)＝D ¹⁶+D ¹²+D ⁵+1

g _CRC16(D)＝D ¹²+D ¹¹+D ³+D ²+D+1

g _CRC8(D)＝D ⁸+D ⁷+D ⁴+D ³+D+1

GSM adopts CRC:CRC40, CRC16, CRC14, CRC12, CRC10, CRC8A, CRC8B, CRC6, CRC3 of 9 kinds of forms, and its generator polynomial is as follows:

g _CRC40(D)＝D ⁴⁰+D ²⁶+D ²³+D ¹⁷+D ³+1

g _CRC16(D)＝D ¹⁶+D ¹²+D ⁵+1

g _CRC14(D)＝D ¹⁴+D ¹³+D ⁶+D ⁵+D ²+1

g _CRC12(D)＝D ¹²+D ¹¹+D ¹⁰+D ⁸+D ⁵+D ⁴+1

g _CRC10(D)＝D ¹⁰+D ⁸+D ⁶+D ⁵+D ⁴+D ²+1

g _CRC8A(D)＝D ⁸+D ⁴+D ³+D ²+D+1

g _CRC8B(D)＝D ⁸+D ⁶+D ³+1

g _CRC6(D)＝D ⁶+D ⁵+D ³+D ²+D+1

g _CRC3(D)＝D ³+D+1

In Fig. 2, when under LTE pattern, switch is connected with LTE branch road, and two common mode CRC calculators calculate first via data respectively, adds CRC24A, common mode CRC calculator 2 add CRC24B in common mode CRC calculator 1 to sequence.Under being switched to TD-SCDMA/GSM, switch is connected with GSM/TD-SCDMA branch road, and two paths of data is sent into common mode CRC calculator 1 and 2 respectively and carried out CRC calculating.The final result that CRC encodes is calculated according to the information sequence of generator polynomial and input.Below to adopt CRC24A generator polynomial to be described under LTE pattern, CRC24A generator polynomial is expressed as:

G _CRC24A(D)＝[D ²⁴+D ²³+D ¹⁸+D ¹⁷+D ¹⁴+D ¹¹+D ¹⁰+D ⁷+D ⁶+D ⁵+D ⁴+D ³+D+1] (1)

Corresponding binary sequence is: 1100001100100110011111011.24 multinomial coefficients are designated as: a ₂₃, a ₂₂..., a ₁, a ₀, a _ivalue is the corresponding D of 1 ⁱ, other are 0.If d ₇, d ₆..., d ₁, d ₀for 8 bit data once inputted, i ∈ [0,23], j ∈ (0,8) are CRC24A result of calculation, and wherein i represents the position of CRC24A, and j represents recursion number of times.8 bit CRC recurrence formula are:

$c_i^{j+1}=c_{i-1}^j+a_i(C_{23}^j+d^j),i\∈\left[\mathrm{1,23}\right],j\∈\left[\mathrm{0,7}\right]---\left(2\right)$

Continuous use formula obtains result of calculation (2) 8 times.Derivation is:

$\begin{array}{c}{c}_i^8=c_{i-1}^7+g_i(c_{23}^7+d_0)\\ =c_{i-2}^6+g_{i-1}(c_{23}^6+d_1)+g_i(c_{23}^7+d_0)\\ =...\\ =c_{i-8}^0+g_{i-7}(c_{23}^0+d_7)+g_{i-6}(c_{23}^1+d_6)+g_{i-5}(c_{23}^2+d_5)+...g_{i-1}(c_{23}^6+d_1)+g_i(c_{23}^7+d_0)\end{array}---\left(3\right)$

CRC24A final result is obtained by (3):

After CRC coding, judge that whether output sequence length be the multiple of 8, if not, then before sequence, add 0 bit obtain the sequence that length is the multiple of 8, otherwise do not process.

Above-mentioned the data obtained is stored in both the buffers, after interleaved signal occurs, carries out interleaving treatment.Wherein multimode intertexture adopts QPP interleaver under LTE pattern, and the information bit of definition to input according to QPP interleaver in 3GPP TS 36.212 agreement interweaves; Under TD-SCDMA pattern, adopt the thought of area throw-over degree, store the interleaving address table of good often kind of block in advance, complete the intertexture often walking 8 bits in the mode of meter reading fast; In gsm mode, form information bit by front 50 most important bits of every block and 132 significant bits, add parity bits and tail bit totally 189 bits carry out interleave address.

1., under LTE pattern, interweave and adopt QPP interleaver, be defined as π (i)=[f according to QPP interleaver in 3GPP TS 36.212 agreement ₁i+f ₂i ²] modK (5)

Can obtain thus: π (i+8)=[f ₁(i+8)+f ₂(i+8) ²] modK

＝[f ₁·i+f ₂·i ²+8f ₁+64f ₂+16f ₂·i]modK

＝π(i)+[8f ₁+64f ₂+16f ₂·i]modK (6)

Interleaving process:

(1) address value of initialization π (0) and π (7), by π (i)=[f ₁i+f ₂i ²] modK i ∈ [0,7] calculates.Consider the requirement of processing speed, can store front 8 bit address of often kind of block in advance, the used time can directly read.

(2) initialization increases progressively parameter: y=π (8)=[8f ₁+ 64f ₂] modK, this parameter is the 8th bit address of block, also can read parameter by above meter reading method, save operation time.

(3) initialization undated parameter g=[16f ₂] modK, equally can meter reading.

(4) 8 bit address of cycle calculations first clock needs: can be released by 8 bit address of last clock, obtaining derivation formula by formula (6) is: π [8*t+i]={ π [8* (t-1)+i]+y}modK i ∈ [0,7], t is present clock, and t-1 is last clock.I represents one in each 8 bit locations.Upgrade and increase progressively parameter y, y=[y+g] modK, in twice above computing, the result after each add operation is all not more than 2K, so modular arithmetic can be asked to be converted into comparison operation by K, as: y=y≤K? y:y-K.According to the address calculated, read data corresponding in buffer, leave relevant position in, reach intertexture object.

(5) being recycled to a blocks of data interweaves complete.

Under 2.TD-SCDMA pattern, adopt the thought of area throw-over degree, store the interleaving address table of good often kind of block in advance, complete the intertexture often walking 8 bits in the mode of meter reading fast.Consider that described CRC coding unit is to the process of list entries, therefore the situation of zero bit is added before may appearing at list entries, if expect in this case, correct interleaved sequence just must make corresponding process when reading interleaving data to its address, and the first address that interleaving data stores adds that namely the address bit corresponding to zero number of bits of interpolation is the first address of first sequence;

Under 3.GSM pattern, the step that GSM also has address to exchange before encoding, is functionally similar to interleaver.Form information bit by front 50 most important bits of every block and 132 significant bits, add parity bits and tail bit totally 189 bits carry out interleave address:

Information bit: u (k)=d (2k) and u (184-k)=d (2k+1) k=0,1 ..., 90

CRC check bit: u (k+91)=p (k) k=0,1,2

Tail bit: u (k)=0 k=185,186,187,188

Coding, mode adjudging device, by judgement, switches under LTE, TD-SCDMA, GSM Three models.

Under LTE/TD-SCDMA pattern, switch is connected with a upper branch road, input coding device 1 and 2 be interleaved sequence and non-interleaved sequence respectively; Under LTE and TD-SCDMA pattern, adopt Turbo coding, generator polynomial is G (D)=[1, g ₁(D)/g ₀(D)], wherein g ₀(D)=1+D ²+ D ³, g ₁(D)=1+D+D ³.Be made up of 3 bit registers, coding staff same pattern owned by France.

Under GSM mode, switch is connected with next branch road, input coding device for interweave after sequence.Adopt convolutional encoding under this pattern, generator polynomial is g ₀=1+D ³+ D ⁴, g ₁(D)=1+D+D ³+ D ⁴, be made up of 4 bit registers.

In order to realize multimode, using originally carrying out Curve guide impeller as Turbo code intertexture Na No. mono-encoder, became 4 calculating from 3 calculating.According to above-mentioned introduction, when pattern is switched to LTE/TD-SCDMA, what a upper road inputted is 8 non-interleaving datas of LTE/TD-SCDMA, and next road input interleaving data, two-way only calculates 3.When being switched to GSM, two-way input is the GSM data after 8 intertextures, and two-way all calculates 4.

Be below the output computing formula of 8 bit parallel codings, z _kbe 8 outputs, c _kfor register original state state value, for updated value, d _kbe 8 input data.

Under LTE/TD-SCDMA pattern, encoder 1 adopts identical transfer function with 2, therefore the output formula of two-way is up and down:

$\left\{\begin{array}{c}{z}_0=d_0+c_0+c_1\\ z_1=d_0+d_1+c_0+c_1+c_2\\ z_2=d_0+d_1+d_3+c_0+c_2\\ z_3=d_0+d_1+d_2+d_3+c_2\\ z_4=d_1+d_2+d_3+d_4+c_1\\ z_5=d_2+d_3+d_4+d_5+c_0\\ z_6=d_0+d_3+d_4+d_5+d_6+c_1+c_2\\ z_7=d_1+d_4+d_5+d_6+d_7+c_0+c_1\\ c_0^1=d_0+d_3+d_4+d_5+d_7+c_1+c_2\\ c_1^1=d_2+d_3+d_4+d_5+d_6+c_0\\ c_2^1=d_1+d_2+d_3+d_5+c_1\end{array}\right.---\left(7\right)$

The output algorithm of GSM two-way is different, corresponding g ₀=1+D ³+ D ⁴output formula be:

$\left\{\begin{array}{c}{z}_0=d_0{+c}_2+c_3\\ z_1=d_1+c_1+c_2\\ z_2=d_2+c_0+c_1\\ z_3=d_0+d_3+c_0\\ z_4=d_0+d_1+d_4\\ z_5=d_1+d_2+d_5\\ z_6=d_2+d_3+d_6\\ z_7=d_3+d_4+d_7\\ c_0^1=d_7\\ c_1^1=d_6\\ c_2^1=d_5\\ c_3^1=d_4\end{array}\right.---\left(8\right)$

Corresponding g ₁(D)=1+D+D ³+ D ⁴output formula be:

$\left\{\begin{array}{c}{z}_0=d_0+c_0+c_2+c_3\\ z_1=d_1+d_1+c_1+c_2\\ z_2=d_1+d_2+c_0+c_1\\ z_3=d_0+d_2+d_3+c_0\\ z_4=d_0+d_1+d_3+d_4\\ z_5=d_1+d_2+d_4+d_5\\ z_6=d_2+d_3+d_5+d_6\\ z_7=d_3+d_4+d_5+d_7\\ c_0^1=d_7\\ c_1^1=d_6\\ c_2^1=d_5\\ c_3^1=d_4\end{array}\right.---\left(9\right)$

In different modes, the coded sequence that the information sequence of input obtains after calculating according to transfer function sends into the output codons obtaining encoder after buffer carries out parallel/serial process, end-of-encode.

These embodiments are interpreted as only being not used in for illustration of the present invention limiting the scope of the invention above.After the content of reading record of the present invention, technical staff can make various changes or modifications the present invention, and these equivalence changes and modification fall into the scope of the claims in the present invention equally.

Claims (3)

1. based on a descending multimode channel coded system for C-RAN platform, it is characterized in that: comprise cyclic redundancy check (CRC) coding unit: for carrying out cyclic redundancy check (CRC) coding to 8 parallel-by-bit input data to be encoded;

Buffer unit: the code signal for exporting cyclic redundancy check (CRC) coding unit stores:

Multimode interleave unit: the mode control signal for sending according to top level control unit selects corresponding interleaving mode to interweave to the data in buffer unit, specifically comprise: when adopting LTE pattern, adopt QPP interleaver, the information bit of definition to input according to QPP interleaver in 3GPP TS 36.212 agreement interweaves; When adopting TD-SCDMA pattern, adopting area to change tachometric method, storing the interleaving address table of often kind of block in advance, complete the intertexture often walking 8 bits in the mode of meter reading; When adopting GSM mode, form information bit by front 50 bits of every block and 132 bits, add parity bits and tail bit totally 189 bits carry out interleave address;

Coding unit: for the output signal of encoding after described CRC coding and the interleaved signal exported through described multimode interleave unit thereof, data carry out parallel input with 8, and described coding unit decides the mode of encoding by mode adjudging;

Top level control unit: for carrying out top level control to cyclic redundancy check (CRC) coding unit, buffer unit, multimode interleave unit, parallel/serial converting unit, comprises model selection control, block size controls and enable signal controls; Chnnel coding in descending multimode chnnel coding is divided into convolutional encoding and Turbo coding according to different patterns.

Parallel/serial converting unit: carry out output encoder sequence after parallel/serial conversion for finally delivering to buffer to the output sequence of CRC coding unit or its information bit after the interleaved sequence that described multimode interleave unit exports is encoded.

2., based on a descending multimode channel coding method for C-RAN platform, it is characterized in that: comprise the following steps:

201, cyclic redundancy check (CRC) coding unit receives input information data, first judge that whether input message sequence length be the multiple of 8, if the multiple of 8, then directly carry out step 202, otherwise add before sequence 0 bit make data block length be 8 multiple, carry out multimode high speed CRC and encode;

202, cyclic redundancy check (CRC) calculating is carried out using 8 bits as a unit, need before calculating to encode according to the different pattern of top level control unit, CRC calculator generator polynomial needed for selection, then calculates final coding result according to the information sequence of CRC generator polynomial and input;

203, buffer unit is stored into the CRC coding result obtained in step 202, and according to the mode control signal control model selector switch of top level control unit, the data in buffer unit are interweaved, specifically comprise: when adopting LTE pattern, adopt QPP interleaver, the information bit of definition to input according to QPP interleaver in 3GPP TS 36.212 agreement interweaves; When adopting TD-SCDMA pattern, adopting area to change tachometric method, storing the interleaving address table of often kind of block in advance, complete the intertexture often walking 8 bits in the mode of meter reading; When adopting GSM mode, form information bit by front 50 bits of every block and 132 bits, add parity bits and tail bit totally 189 bits carry out interleave address;

204, after the multimode interleaving steps in step 203, the output signal after being encoded by CRC and the interleaved signal through the output of multimode intertexture thereof are encoded, and concrete steps are: under GSM mode, and switch is connected with next branch road, adopt convolutional encoding under this pattern; Under LTE/TD-SCDMA pattern, switch is connected with a upper branch road, input coding device 1 and 2 be interleaved sequence and non-interleaved sequence respectively; Under LTE and TD-SCDMA pattern, adopt Turbo coding;

205, buffer is finally delivered to the output sequence of CRC coding unit or its information bit after the interleaved sequence that described multimode interleave unit exports is encoded and carry out output encoder sequence after parallel/serial conversion, judge that whether output sequence length be the multiple of 8, if not, before sequence, then add 0 bit obtain the sequence that length is the multiple of 8, otherwise do not process.

3. the descending multimode channel coding method based on C-RAN platform according to claim 2, is characterized in that: the LTE in step 203 adopts CRC:CRC24A, CRC24B, CRC16, CRC8 of 4 kinds of forms; TD-SCDMA also adopts CRC:CRC24, CRC16, CRC12, CRC8 of 4 kinds of forms, and GSM adopts CRC:CRC40, CRC16, CRC14, CRC12, CRC10, CRC8A, CRC8B, CRC6, CRC3 of 9 kinds of forms.