WO2011137790A1

WO2011137790A1 - Method and apparatus for sending/receiving common public radio interface service

Info

Publication number: WO2011137790A1
Application number: PCT/CN2011/074316
Authority: WO
Inventors: 蒋亚军; 包盛花; 黄春行; 董晓青
Original assignee: 华为技术有限公司
Priority date: 2010-11-18
Filing date: 2011-05-19
Publication date: 2011-11-10
Also published as: CN102025448B; CN102025448A

Abstract

A method and an apparatus for sending/receiving Common Public Radio Interface (CPRI) service are provided by the present invention. The sending method includes: adding a check bit into a service flow code-block to obtain a check code-block, and forming a check frame with multiple check code-blocks, wherein the check bit added into the service flow code-blocks of the current check-frame is the check-bit of the service flow code-blocks of the previous check frame (201); forming a hyperframe with multiple check frames, and identifying the frame header of the hyperframe (202); sending the identified hyperframe (203). According to the present invention, high efficient line coding mechanism can be adopted in CPRI interface service transmission, and corresponding check protection mechanism and hyperframe synchronization mechanism are provided, and therefore the application requirement on transmission rate of the CPRI next generation can be met.

Description

General public wireless interface service transmitting/receiving method and device The present application claims to be submitted to the Chinese Patent Office on November 18, 2010, the application number is 201010549681.9, and the invention name is "general public wireless interface service transmitting and receiving method and device" Chinese patent Priority of the application, the entire contents of which are incorporated herein by reference.

Technical field

The present invention relates to the field of communications technologies, and in particular, to a method and an apparatus for transmitting and receiving a general public radio interface service.

Background technique

The CPRI (Common Public Radio Interface) specification mainly defines a protocol interface between a radio base station and a base station controller for communication between a base station and a base station controller.

The line coding format of the CPRI existing standard (rate less than or equal to 6.144 Gbps) protocol is 8B/10B, that is, the 8-bit codeword is mapped to the 10-bit codeword coding mode. The coding process is shown in Figure 1: Data code The stream is presented at the encoder input with 8 bits, and the 8-bit data is logically divided into two parts: the start 5 bits and the last 3 bits. The start 5-bit data is input to the 5B function module to generate DC (Direct Current) balance-related encoding functions. The last 3 bits are also input to the 3B function module, which generates the DC balance-related coding function. Both the 5B function module and the 3B function module are used to determine the DC balance of the final code. The balance control module uses the DC balance information provided by the function module to determine the DC balance code, and the final code is implemented in the 5B/6B and 3B/4B coding modules.

In the current CPRI standard, the application scheme of the line coding is also specified, LOS ( Loss of

Signal, loss of signal / LOF (Loss of Frame) mechanism. However, in the process of implementing the embodiments of the present invention, the inventors have found that the existing 8B/10B encoding method cannot meet the application requirements of the next generation of CPRI standards (rates greater than or equal to 9.8304 Gbps), mainly reflected in the following points:

1. When the 8B/10B code is applied to the lOGbps transmission system, the crosstalk of the code itself is too high, which is not conducive to system transmission.

2. The efficiency of 8B/10B coding is low, and the waste of resources is large, which cannot meet the needs of CPRI high-speed evolution.

Summary of the invention

Embodiments of the present invention provide a method and an apparatus for transmitting and receiving a general public wireless interface service, Improve line coding efficiency, reduce crosstalk effects, and meet CPRI's next-generation application requirements for transmission rates. To this end, the embodiments of the present invention provide the following technical solutions:

A general public wireless interface service sending method includes:

Adding a check bit in the service stream coding code block to obtain a check code block, and multiple check code blocks form a check frame, and the check bit added in the service stream code block in the current check frame is a check digit of a service stream coded block in a check frame;

Forming a plurality of school insurance frames into a super frame, and identifying a frame header of the super frame;

The superframe after the identity is sent.

A general public wireless interface service receiving method includes:

Performing codeword synchronization on the received service code stream to identify a check code block;

Identifying superframe boundaries based on superframe header characteristics;

Determining a check frame by using a superframe boundary, and a superframe contains an integer number of check frames;

Performing error detection or error correction on the service stream coded code block according to the check bits in each check code block in the check frame;

Removing the check bit in the check code block to obtain a service stream code block;

Decoding the service stream coded block to obtain decoded service data.

A universal public wireless interface service sending device includes:

a check frame generating unit, configured to add a check bit in the service stream coded code block to obtain a check code block, and the plurality of check code blocks form a check frame, and the service stream code block in the current check frame The check bit added in is the check digit of the service stream coding code block in the previous check frame;

a superframe generating unit, configured to form a plurality of check frames into a super frame, and identify a frame header of the super frame; and a sending unit, configured to send the identified super frame.

A universal public wireless interface service receiving apparatus includes:

a codeword identifying unit, configured to perform codeword synchronization on the received service code stream to identify a check code block, and identify a superframe boundary according to the superframe header feature;

a check frame identifying unit, configured to delimit a check frame by using a superframe boundary, where one superframe includes an integer number of check frames;

a check frame detecting unit, configured to perform error detection or error correction on the service stream coded code block according to the check bit in each check code block in the check frame; a code block obtaining unit, configured to remove a check bit in the check code block to obtain a service stream coded block;

And a decoding unit, configured to decode the service stream coded code block to obtain decoded service data. The method and device for transmitting and receiving a common public radio interface service according to an embodiment of the present invention, adopts an efficient line coding mechanism for CPRI interface service transmission, and provides a corresponding check protection mechanism and a superframe synchronization mechanism for the demand of CPRI high-speed evolution, and The check bit added in the service flow code block in the current check frame is the check bit of the service stream code block in the previous check frame, which saves the transmission buffer and ensures compatibility with the CPRI standard, thereby ensuring the compatibility. CPRI's next-generation application requirements for transmission rates. Correspondingly, at the receiving side, performing codeword synchronization on the received service code stream to identify the check coded block, and identifying the superframe boundary according to the superframe header feature, since one superframe contains an integer number of check frames Therefore, the boundary of each check frame in the superframe may be further determined, and the service stream coded block may be error-detected or corrected according to the check bits in each check code block in the check frame, and the check is removed. The check bit in the code block is obtained, and the service stream code block is obtained, and the code block of the service stream is decoded to obtain the decoded service data, thereby ensuring the correctness of the received data.

DRAWINGS

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings to be used in the embodiments will be briefly described below. Obviously, the drawings in the following description are only in the present invention. Some of the embodiments described may also be used to obtain other figures from those of ordinary skill in the art in view of these drawings.

1 is a schematic diagram of a process of encoding 8B/10B lines of CPRI in the prior art;

2 is a flowchart of a method for transmitting a general public radio interface service according to an embodiment of the present invention;

3 is a schematic diagram of a 32B/34B coding mode according to an embodiment of the present invention;

4 is a schematic diagram of a process of generating a FEC block in an embodiment of the present invention;

Figure 5 is a schematic diagram of 32B/34B encoding and 32/35B in the embodiment of the present invention;

6 is a format of a superframe sync header in an embodiment of the present invention;

7 is a flowchart of a method for receiving a general public radio interface service according to an embodiment of the present invention;

8 is a flowchart of an implementation of the WORD ALIGNMENT mechanism in the embodiment of the present invention; FIG. 9 is a schematic diagram of an error detection process of the FEC block in the embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a general public radio interface service sending apparatus according to an embodiment of the present invention; Figure

FIG. 11 is a schematic structural diagram of a general public radio interface service receiving apparatus according to an embodiment of the present invention.

detailed description

The embodiments of the present invention are further described in detail below with reference to the accompanying drawings and embodiments.

In the CPRI standard evolution work, for the next generation of CPRI standards (rate greater than or equal to 9.8304 Gbps), the applicant proposed a line coding method, specifically: encoding the code stream, including data frames in the code stream The payload, the n-bit continuous data of the same position in each of the at least b segments of each of the consecutive N bits, is converted to m-bit continuous data, and the b is an integer greater than or equal to 2, N, n and m are all integers greater than 0, bxn < N, m > n. Specifically, when encoding the code stream, converting n-bit continuous data to m-bit continuous data according to the n/m line coding table, wherein each n-bit continuous data in the n/m line coding table corresponds to one polarity deviation RD (Running Disparity) is a negative m-bit continuous data and/or a polarity deviation RD is positive m-bit continuous data, wherein, in the m-bit continuous data in which RD is negative, the number of 0s is greater than or equal to 1. Number, RD is the number of zeros in the positive m-bit continuous data that is less than or equal to 1. Of course, it is also possible to define the number of 0s in the m-bit continuous data whose RD is negative is less than or equal to 1, and RD is the number of positive m-bit continuous data whose number of 0 is greater than or equal to 1. Whether RD is positive or negative is only to illustrate the comparison of the number of 0s and 1s in the corresponding data stream. Wherein, the n/m line coding table may be a 5B/6B coding table, or a 3B/4B coding table, correspondingly, n=5, m=6 or n=3, m=4. The n/m line coding table can also be a commonly used coding table such as 4B/5B, 8B/9B or 8B/10B.

Preferably, N is 32, b is 2, n is 5, and m is 6, that is, 5B/6B code mapping processing is performed on some bits of the bit code stream entering the encoder, and the remaining bits are not processed by the text mapping.

In addition, in order to ensure the coding performance, all bit code streams need to be scrambled before encoding. This kind of line coding can avoid the occurrence of ISI (Inter Symbol Interference) effect, such as 64B/66B encoding length 0 and length 1 data, ensuring DC balance, and avoiding the jump edge after 8B/10B encoding. The problem of excessive probability of crosstalk is caused by the high probability of occurrence, ensuring the physical electrical transmission performance of the code, and compatible with CPRI's low-rate applications. Method and device for receiving.

As shown in FIG. 2, it is a flowchart of a method for transmitting a general public radio interface service according to an embodiment of the present invention, which includes the following steps:

Step 201: Add a check bit in the service stream coding code block to obtain a check code block, and multiple check code blocks form a check frame, and the check added in the service stream code block in the current check frame The bit is the parity bit of the service stream coded block in the previous check frame.

It should be noted that, in the embodiment of the present invention, the service stream coding code block is a 32B/34B code code block, the check code code block is a 32B/35B code code block, or the service stream code code block is used. It is a coded block of 36B/40B without a check bit, and the check code block is a 36B/40B code block.

The service stream coded code block may be a 32B/34B coded code block, i.e., a 32-bit codeword is mapped to a coded block of a 34-bit codeword according to the line coding method proposed by the applicant, as shown in FIG.

The principles of 32B/34B coding mainly include:

(1) adding a special processing to the bit stream by using a 32-bit payload as a unit;

(2) 5B/6B encoding is performed in the first 5 bits of 16 bits, and the last 11 bits are reserved without any processing.

Certainly, the embodiment of the present invention does not limit the specific encoding format of the service stream coding code block, for example, it may also be an encoding format such as 36B/40B.

The bits of the 36B/40B code represent the meaning:

[31:0]: user service code stream data;

[35:32]: control word;

[39]: Flip indicator (indicating whether [35:0] needs to be flipped);

[38:37]: Synchronization header bits;

[36]: Check digits, including FEC check digit, CRC check digit, parity bit. In addition, in the embodiment of the present invention, the check bit inserted in the middle of the service stream coding code block is at least 1 bit. For example, a 1-bit parity bit may be added to the header of the 32B/34B code block, and accordingly, the generated check code block is a 32B/35B code block. Of course, the check bits can be inserted into any position of the service stream code block, which is not limited in this embodiment of the present invention.

Specifically, the check code block and the check frame may be generated in the following manner:

Inserting each bit in the parity bit generated for the i-1th check frame into the service stream coded code block; And according to the RD polarity of all the coded code streams and the RD polarity of the part of the payload of the currently coded service stream coded block, the service stream code block of the current code stream to be coded is subjected to service flow coding to obtain a service stream coded code block. And further, the obtained service stream coded code block and the check bits interpolated into the obtained service stream coded code block constitute a check code block; the RD polarity of all coded code streams is updated; The plurality of check code blocks constitute the i-th check frame.

The all coded code stream is a 32B/35B coded code stream, and the service stream is coded as a 32B/35B code; or, the coded code stream is a 36B/40B coded code stream, and the service stream is encoded. Coded for 36B/40B.

It should be noted that the check bit may be an FEC check bit, or a CRC check bit, or a parity bit. Moreover, the check bit added in the current check frame is the check bit of the service stream code block in the previous check frame, that is, the correctness of the previous check frame is protected by the latter check frame.

Step 202: Form multiple check frames into one super frame, and identify a frame header of the super frame.

Step 203: Send the superframe after the identification.

In the embodiment of the present invention, in order to ensure the correctness of the data transmission, a check protection mechanism, such as FEC (Feedforward Error Correction) protection, is added, that is, an FEC check bit is added in the service stream coding block. So that the receiving end detects the correctness of the received code block according to the check bit.

With the method of the embodiment of the present invention, the 10 Gbps transmission requirement of the CPRI next-generation standard can be met. For example, the framing mode can be adopted: every 32 32B/35B coded code blocks form a check frame, and the implementation is implemented (1120, 1088, 32) Encoding, that is, using a 32-bit overhead bit, protecting the payload of 1088 bits, the length of the entire check frame is 1120 bits. Of course, the embodiment of the present invention does not limit the specific number of check code blocks that constitute the check frame.

The following describes the implementation process of the foregoing step 201 by adding a 1-bit parity bit to the header of the service stream coding block and forming an FEC frame by 32 parity code blocks.

A complete FEC frame contains 32 bits of parity bits and 32 32B/34B coded code blocks that are interleaved into the 1-bit code header of each 32B/35 coded code block that makes up the FEC frame. This type of processing can effectively avoid the long 0 and long 1 problems that can be caused by the 32-bit check digit.

In order to further avoid the DC (Direct Current) imbalance problem that may be caused by the 32-bit check bit, in the embodiment of the present invention, the overhead bit of the FEC frame is allocated in the following manner: Special check digit:

For the first transmitted FEC frame, its 32-bit school insurance bit is filled with all 0s;

For the i-th (i is an integer greater than 1) FEC frame, the 32-bit check digit needs to be filled with the 32-bit parity bit generated by the i-1th FEC frame, and the specific filling manner is as shown in FIG. Show.

Referring to Fig. 4, the case where the overhead bits of the i-th FEC frame are filled with the 32-bit parity bits generated for the i-1 FEC frames will be described.

For the first 32B/35B encoding, the first 32B/34B encoding is first performed on 32 bits, and the 32B/34B encoding includes a part of the codeword inversion processing of 32 bits and an RD polarity identification of another partial codeword. The RD polarity identifier is determined according to whether the part of the codeword is inverted. If the part of the codeword is inverted, the RD polarity of the other part of the codeword is negative, if the part of the codeword is not inverted, or When a portion of the codeword should be inverted and the RD value of the other portion of the codeword has only a positive value, the RD polarity is positive and the portion of the codeword is not flipped. It should be noted that, when determining the RD polarity of the current 32B/34B code block to be coded, only the 22-bit payloads of the positions [10: 0] and [26: 16] in the 32B/34B code block are determined. Statistics, where [10: 0] represents the 0th to 10th bits of the 34 bits, and [26: 16] represents the 16th to 26th bits of the 34 bits, which are subsequently the same. If all the encoded code streams before the current 32B/34B code block to be coded are the same as the 22 bits RD of the positions [10: 0] and [26: 16] in the 32B/34B code block to be currently coded, and the current When any one or two of [15: 11] and [31: 27] have a negative RD, the position of the current 32B/34B code block to be coded [10: 0] and [26: 16] is 22 The bit is flipped, and any one or two of [15: 11] and [31: 27] are simultaneously RD-identified to generate a first 32B/34B code block; otherwise, if the current 32B/34B is to be processed All the encoded code streams before the coded block and the 22-bit RDs of the positions [10: 0] and [26: 16] in the 32B/34B code block to be coded are the same, but the current [15: 11] and [31: 27] does not have RD negative value, or all the coded code streams before the current 32B/34B code block to be coded and the current position of the 32B/34B code block to be coded [10: 0] and [26: 16] If the 22-bit RD has the opposite polarity, no flipping is performed, and RD+ is applied to [15: 11] and [31: 27] to generate the first 32B/34B code block, and then 32 bits. check The first bit of the first parity bit is added to a 32B / 34B code block is encoded Harbor, 1st generation 32B / 35B encoded code blocks.

For the second 32B/35B coded code block, the 32B/34B code is first encoded, and not only the RD polarity of the current 32B/34B code block to be coded but also the code block to be coded in the 32B/34B code block is determined. The RD polarity of all previous coded code streams, if the RD polarity of the current 32B/34B code block to be coded is the same as the RD polarity of all previous coded code streams, and the other of the 32B/34B code blocks to be coded When some codewords have a negative RD value, the 22 bits of the current 32B/34B code block to be coded [10: 0] and [26: 16] are inverted, and the corresponding [15: 11] and [ 31: 27] Perform the RD flag, and add the check bit of the second bit of the 32-bit check bit to the terminal of the second 32B/34B code block to generate the second 32B/35B code block. Otherwise, if all the coded code streams before the current 32B/34B code block to be coded and the current position to be coded 32B/34B code block are [10: 0] and [26: 16], the 22 bits have the same RD polarity. , but the current [15: 11] and [31: 27] do not have RD negative values, or all the encoded code streams before the current 32B/34B code block to be coded and the position in the current 32B/34B code block to be encoded [10: 0] and [26: 16] These 22-bit RDs have opposite polarities, and no flipping is performed. The corresponding [15: 11] and [31: 27] are RD+-identified, and the 32-bit check is performed. The second bit in the bit A check bit is added to the wharf of the second 32B/34B code block to generate a second 32B/35B code block. And so on, until the 32nd 32B/35B coded block is generated.

Finally, the generated 32 32B/35B coded code blocks form the i-th FEC frame.

As shown in Fig. 5, a schematic diagram of a 32B/34B coded code block and a 32B/35B coded code block is shown. It should be noted that, in order for the receiving end to recognize such a flip, two 5B codes in the current code block to be coded may be RD- as bits [15: 11] and bits [31: 27] respectively. 5B/6B coding mapping, the mapping table is shown in Table 1. If one of the two 5B codes does not have an RD-map, then the 5B code is mapped to RD+. If neither of the 5B codes has an RD-map, the 22 bits in the current code block to be coded are not flipped, and both 5B codes are mapped to the 5B/6B code of RD+.

5B (original code) RD+(6B) RD-(6B)

00000 100111 011000

00001 011101 100010

00010 101101 010010

00011 110001

00100 110101 001010

00101 101001 00110 011001

00111 111000 000111

01000 111001 000101

01001 100101

01010 010101

01011 110100

01100 001101

01101 101100

OHIO 011100

01111 010111 101000

10000 011011 100100

10001 100011

10010 010011

10011 110010

10100 001011

10101 101010

10110 011010

10111 111010 000101

11000 110011 001100

11001 100110

11010 010110

11011 110110 001001

11100 001110

11101 101110 010001

11110 011110 100001

11111 101011 010100

For the receiving end, as long as the codeword of RD- is recognized at any of the two 5B/6B encoding positions, the 22 bits of the currently received 32B/34B code block are flipped, if recognized. The RD codewords are all positive and do not flip the 22 bits in the current code block. In the embodiment of the present invention, a 32-bit check bit for each FEC frame may be generated by using an FEC generator polynomial g ^ ^ + ^ + ^ + + + +l, where the X represents a shift register, and the power representation shift The location of the bit register. The FEC generator polynomial can refer to the description in the 802.3AP standard and will not be described in detail here.

It should be noted that, the embodiment of the present invention does not limit the number of 32B/35B coded code blocks constituting the FEC frame. For example, 64 32B/35B coded code blocks may be used to form one FEC frame.

In the embodiment of the present invention, multiple check frames may be combined into one super frame. For example, 32 FEC frames may be combined into one super frame. At the same time, a superframe synchronization mechanism is also set, that is, the frame header of the superframe is identified in the above step 202.

In the existing CPRI protocol, the common control word of the super frame header under various line rates is K28.5, and after K28.5, codewords of different lengths are filled according to the different CPRI line rates.

In the embodiment of the present invention, the frame header of the superframe may be identified by using the control word K28.5, and the superframe synchronization of the 32B/35 encoding may be referred to FIG. 6 in order to maintain the same character detection mechanism as the existing CPRI protocol. The format shown.

The upper line indicates the superframe header before encoding, and the lower line indicates the superframe header after 32B/34B encoding.

Different from the existing CPRI protocol, in the embodiment of the present invention, the control word K28.5 adopts the mapping manner as shown in Table 2.

Table 2:

And, if the number of 1s in all transmitted codes is greater than or equal to 0 (referred to as RD+), the codeword of the control word K28.5 is mapped to "1100000101", that is, the RD-map value is selected. If the number of 1s in all transmitted codes is less than 0 (referred to as RD-), the codeword of control word K28.5 is mapped to "0011111010", that is, the RD+ mapped value is selected.

In the embodiment of the present invention, the [23:0] field of the superframe header remains unchanged, that is, [23:0] adopts a fixed special character. In the embodiment of the present invention, a general public radio interface service sending method is adopted, and an efficient line coding mechanism is adopted for CPRI interface service transmission, and a corresponding check protection mechanism and a superframe synchronization mechanism are provided, and the current check is performed. The check bits in the frame are interpolated into the next check frame to ensure DC balance, thus ensuring the application requirements of the next generation of CPRI for the transmission rate.

Correspondingly, for the foregoing CPRI service sending method, at the receiving end, the received service code stream needs to be synchronized, so as to perform correct de-frame processing on the service data. The synchronization of the service code stream mainly includes the following aspects: The boundary of the super frame boundary and the second code block are correctly identified from the received service code stream.

To this end, the embodiment of the present invention further provides a general public wireless interface service receiving method, as shown in FIG. 7, which is a flowchart of the method, including the following steps:

Step 701: Perform codeword synchronization on the received service code stream to identify a check code block. Step 702: Identify a superframe boundary according to the superframe header feature.

The received service code stream is a 32B/35B coded code stream or a 36B/40B coded code stream. Correspondingly, according to the superframe header feature, the superframe boundary is identified by identifying a superframe boundary of the 32B/35B encoded code stream by detecting k28.5 characters; or identifying a 36B/40B encoded bitstream by detecting 10 characters. Superframe boundary.

Step 703: Delimit a check frame by using a superframe boundary, where one superframe includes an integer number of check frames. After the superframe boundary is identified, the boundary of each check frame in the superframe can be determined according to the number of check frames included in each superframe.

Step 704: Perform error detection or error correction on the service stream coded block according to the check bits in each check code block in the check frame.

Step 705: Remove the check bit in the check code block to obtain a service stream code block. Step 706: Decode the service stream coded code block to obtain decoded service data. To determine the boundary of the superframe header, the following is an example of verifying that the coded block is a 32B/35B code block. The main process is as follows:

The receiver selects a bit from the traffic code stream entering the receiver, and starts synchronization detection from the bit. Synchronous detection is based on the assumption that the bit is the boundary of the superframe header, or the boundary of the 32B/35B codeword, then the frame header of the superframe should appear at a specific position from the bit to the back, that is, there is 8B/10B Encode K28.5, or appear 5B/6B encoding unique to 32B/35 code block. If the detection of a particular location finds these special characters, then the current candidate is considered to be the frame header of the superframe, or the boundary of the 32B/35B codeword.

If it is found that there is no such special character in the specific location, then the current candidate bit is considered to be neither the boundary of the superframe nor the 5B/6B encoding unique to the 32B/35 coded block, the current bit is discarded, and the next bit is used as the candidate bit. Repeat the above steps until you find a bit that matches those special characters.

In the embodiment of the present invention, the WORD ALIGNMENT mechanism can be implemented by means of a state machine, and the specific implementation process can be various, which are respectively illustrated below.

Example 1: The state machine includes the following states: a LOCS of Sync state, a Comma Detect state, a Synchronized state, and a Synchronized error state. It mainly includes the following processes:

In the unsynchronized state of the codeword, a predetermined bitstream pattern is searched from the received service code stream by windowing, such as the above superframe header or the 5B/6B encoded 6B codeword, and enters the codeword character detection state; a codeword character detection state, continuing to detect data subsequent to the bitstream pattern, if the subsequent data of the bitstream pattern is a legal code, and is the predetermined bitstream pattern, and the number thereof reaches a first predetermined a value, then entering a codeword synchronization state; if the subsequent data of the bitstream pattern is an illegal code, returning to a codeword unsynchronized state; the legal code indicating that the data is a superframe frame header bitstream, or 5B/ 6B valid characters in the 6B code mapping table; the illegal code indicates that the data is not a superframe frame header bit stream, and is not a 6B valid character in the 5B/6B code mapping table;

In the codeword synchronization state, if the subsequently received data is a legal code, the codeword synchronization state is maintained; if the received data is an illegal code, the codeword synchronization error state is entered;

In the codeword synchronization error state, if the number of received illegal codes reaches the second predetermined value, the codeword is not synchronized; if the number of received legal codes reaches the third predetermined value, the illegal code will be received. The number is reduced by 1; when the number of illegal codes received is reduced to 0, the codeword synchronization state is entered;

If the state machine is in the codeword synchronization state or the codeword synchronization error state, it is determined that the word boundary has been found. The first predetermined value is the number of valid bitstream patterns that are required to be received by the state machine when entering the codeword synchronization state; the second predetermined value is required to be received when the state machine enters the codeword unsynchronized state. The invalid codeword is the number of illegal codes; the third predetermined value is the number of consecutive valid codewords that the state machine needs to receive into the codeword synchronization state, that is, the number of legal codes. The first predetermined value, the second predetermined value, and the third predetermined value may be set by the user according to actual application needs, such as may be set according to delays, resources, and requirements for stability of the synchronization state that the service can receive. For example, to prevent false synchronization, it is necessary to detect 16 or 64 valid characters to report synchronization, that is, the first predetermined value can be set to 16 or 64. Similarly, in order to prevent small disturbances from breaking the codeword synchronization state, it is necessary to detect Unsynchronization can only be reported when the number of valid characters reaches a certain number.

It should be noted that since the 32B/35B encoding is different from the existing 8B/10B encoding, the synchronization mechanism specified in the WORD ALIGNMENT mechanism and the CPRI existing protocol is also different, as follows:

The judgment basis for the current data to be detected is invalid is:

1. The [33:24] bits of the detected data, the [33:24] represents the 24th to 33rd bits in a code stream, and if the k28.5 codeword specified by the superframe header is not met, the current detected data is determined. Not a super frame header;

2. Check the [16:11] or [33:28] bits of the data. If the 5B/6B code table is not met, determine that the current test data is not a 5B/6B codeword.

The judgment basis for the current data to be detected is valid is:

1. The [33:24] bits of the detected data, if the k28.5 codeword specified by the superframe header is met, it is determined that the superframe header is valid;

2. Check the [16:11] and [33:28] bits of the data. If the 5B/6B code table is met, it is determined that the current test data is not a 5B/6B codeword.

Example 2: The state machine includes the following states: a codeword unsynchronized state, a codeword character detection state, a codeword synchronization state, and mainly includes the following processes:

In the unsynchronized state of the codeword, a predetermined bitstream pattern is searched from the received service code stream by windowing, such as K28.5, or [16:11] and [33:28] are both 5B/6B encoded. Code table, enter the character detection state;

In the codeword character detection state, the data subsequent to the bitstream pattern is continuously detected, if the data subsequent to the bitstream pattern is continuously detected as a legal code, and the predetermined bitstream map is If the number of cases reaches a fourth predetermined value, such as 64, the codeword synchronization state is entered; if the subsequent data of the bitstream pattern is an illegal code, the codeword is not synchronized; the legal code indicates that the data is a superframe header bitstream, or a 6B valid character in a 5B/6B coding mapping table; the illegal code indicating that the data is not a superframe header bitstream, and is not a 6B valid character in the 5B/6B coding mapping table In the codeword synchronization state, it is necessary to continue to detect the codeword synchronization state to ensure that the codeword boundaries received subsequently are correct. If the subsequently received data is a legal code, the codeword synchronization state is maintained; if the number of subsequent received data is the fifth predetermined value, such as 16, the codeword is not synchronized; the boundary is not found;

If the state machine is in the codeword synchronization state or the codeword synchronization error state, it is determined that the superframe boundary has been found.

The fourth predetermined value and the fifth predetermined value may be set according to an application requirement, for example, according to a service receivable delay, a resource, and a requirement for synchronization state stability. A specific implementation flow chart includes the following steps:

Step 801, resetting, that is, in the unsynchronized state, searching for a 32B/35B codeword conforming to the 5B/6B code table from the received service code stream by windowing, and entering a character detection state;

Step 802, performing serial bit sliding, and the synchronization counter is returned to 0;

Step 803, obtaining the next character;

Step 804, determining whether the obtained character is valid; if yes, performing step 805; otherwise returning to step 802;

Step 805, it is determined whether the number of valid times of the character reaches 63 times; if yes, step 807 is performed; otherwise, step 806 is performed;

Step 806, the value of the valid character counter is increased by 1;

Step 807, 32B/35B codeword locking, that is, entering the codeword synchronization state;

Step 808, the value of the invalid character counter is returned to 0;

Step 809, obtaining the next character;

Step 810, determining whether the acquired character is valid; if yes, performing step 811; Step 813;

Step 811, it is determined whether the number of times the character is valid reaches 63 times; if yes, step 808 is performed; otherwise, step 812 is performed;

Step 812, the value of the valid character counter is incremented by 1; then returns to step 809;

Step 813; determining whether the number of invalid characters has reached 15 times on the premise that one character has been invalidated; if yes, returning to step 801; otherwise, executing step 814;

In step 814, the value of the invalid number counter is incremented by 1, and the value of the synchronization counter is returned to 0; then, the process returns to step 809.

Through the above two methods, the superframe boundary can be correctly identified to ensure correct deframing of the received data.

In the embodiment of the present invention, based on the protection mechanism adopted by the transmitting end, correspondingly, in the above steps

In 802, whether the verification frame transmission is correct or not can also be detected by the serial bit sliding method. The correctness of the current verification frame transmission needs to be performed after receiving the next verification frame. Specifically, after receiving the current check frame, acquiring a payload in the current check frame, and generating a check bit of the service stream coded block in the current check frame according to the payload, and generating a check with the sender. The bit is in the same way, for example, it can be generated by using the FEC generator polynomial g ^ ^ + ^ + ^ + + + l; if the check bit of the service stream code block in the current check frame is generated and the next check frame If the check bits are the same, it is determined that the current check frame is transmitted correctly. Otherwise, the current check frame transmission error is determined, and the error correction is required. The specific manner of error correction may be processed according to the prior art, and details are not described herein again.

Referring to FIG. 9, it is a schematic diagram of a check frame error detection process in the embodiment of the present invention.

For the sake of clarity, in this embodiment, a check frame includes 32 check code blocks as the payload in the i-1th check frame after receiving the i-1th check frame. Generating a 32-bit check bit for the i-1th check frame, assuming A, retaining the check bit A, and after receiving the i-th check frame, acquiring 32 bits of the i-th check frame The check digit is assumed to be B.

The description of the method for transmitting the common public radio interface service in the foregoing embodiment of the present invention shows that the 32-bit check bit inserted in the middle of the i-th check frame is for the service stream coded block in the i-1th check frame. Check Digit. Therefore, by comparing whether the check bit A and the check bit B are the same, it can be determined whether the i-1th check frame is correctly transmitted. If the check bit A is the same as the check bit B, it is determined that the i-1th check frame is transmitted. The input is correct; otherwise, the i-1th check frame is not transmitted correctly. In this case, it can be slid to a candidate bit for the same match detection.

In the embodiment of the present invention, a LOS (Loss of Signal) mechanism is also provided, which mainly includes two parts:

If it is detected within a superframe that the 32B/35B coded code block in the check frame is in an unsynchronized state check frame, the LOS state is indicated;

If it is detected within a superframe that the 32B/35B coded code block in the check frame is in a synchronized state, and there is no check bit mismatch in the superframe, the LOS termination state is indicated.

For 32B/35B encoding, when applied to the CPRI next-generation transmission standard, the state of the L0S has two criteria:

(1) The 32B/35B codeword synchronization state is an unlocked state, that is, the state machine is in an unsynchronized state;

(2) In a superframe, the check bits of the service stream coded code block in at least 16 check frames do not reach the foregoing matching state, that is, the check bits of the service flow coded code block in the generated current check frame and The check digits in the next check frame are the same;

In addition, in CPRI optical transmission applications, the LOS state is also caused when the received optical power is below the detection threshold.

It should be noted that the detection of the LOS state is performed in the same superframe.

(2) LOS status termination:

The termination condition of the LOS state is: The 32B/35B codeword is in a locked state, that is, the state machine is in a synchronized state, and there is no FEC check bit mismatch in the superframe.

In the embodiment of the present invention, a common public radio interface service receiving method performs codeword synchronization on a received service code stream, and identifies a boundary of a second coding block in a superframe boundary and a check frame; according to each check code in the check frame The check bit in the block performs error detection or error correction on the service stream coding, removes the check bit in the check code block, and obtains the service stream code block; decodes the code block of the service stream, and after decoding The business data ensures the correctness of the received data.

A person skilled in the art can understand that all or part of the steps of implementing the above embodiments can be completed by a program to instruct related hardware, and the program can be stored in a computer readable storage medium, the storage. Media, such as: ROM/RAM, disk, CD, etc. Correspondingly, the embodiment of the present invention further provides a general public radio interface service sending apparatus, as shown in FIG. 8, which is a schematic structural diagram of the apparatus.

In this embodiment, the universal public radio interface service sending apparatus includes:

The check frame generating unit 1001 is configured to add a check bit in the service stream coded code block to obtain a check code block, and the plurality of check code blocks form a check frame, and the service stream code in the current check frame The check bit added in the block is the check digit of the service stream coding code block in the previous check frame;

a superframe generating unit 1002, configured to form a plurality of check frames into one superframe, and identify a frame header of the superframe;

The sending unit 1003 is configured to send the identified superframe.

In the embodiment of the present invention, the service flow coded code block is a 32B/34B coded code block, and the school coded coded code block is a 32B/35B coded code block. Correspondingly, the device further includes:

A check bit generating unit 1004 is configured to generate a 32-bit check bit by using a polynomial g ^ ^ + ^ + ^ + c u + + l , wherein the X represents a shift register, and the power represents a position of the shift register.

In a specific application, the check frame generating unit 1001 may interpolate each bit of the 32-bit check bit generated by the check bit generating unit 1004 into the header of the service stream coded block to generate a check code block, and For example, the description of the common public radio interface service sending method in the embodiment of the present invention is omitted, and the details are not described here.

In the embodiment of the present invention, the superframe generating unit 1002 may identify the frame header of the superframe by using the control word K28.5, and if the number of all the transmitted codes is greater than or equal to 0 When counting, the codeword of the control word K28.5 is mapped to "1100000101". If the number of 1s in all transmitted codes is less than 0, the codeword of the control word K28.5 is mapped to "0011111010". . For details, refer to the previous description.

In the embodiment of the present invention, the service stream coding code block may also be a 36B/40B coded code block without a check bit, and the school insurance code code block is a 36B/40B code code block.

The general public radio interface service sending apparatus of the embodiment of the invention adopts an efficient line coding mechanism for the CPRI interface service transmission, and provides a corresponding check protection mechanism and a super frame synchronization mechanism, and the current check frame, for the demand of the CPRI high-speed evolution. The check digit added in the medium stream coding code block is the check digit of the service stream coding code block in the previous check frame, which ensures the DC balance, thereby ensuring the application requirement of the CPRI next generation for the transmission rate. Correspondingly, the embodiment of the present invention further provides a general public radio interface service receiving apparatus, as shown in FIG. 11, which is a schematic structural diagram of the apparatus.

In the embodiment of the present invention, the general public radio interface service receiving apparatus includes: a codeword identifying unit 1101, configured to perform codeword synchronization on the received service code stream, to identify a check coded block, and according to the superframe header Feature, identifying a superframe boundary;

a check frame identifying unit 1102, configured to delimit a check frame by using a superframe boundary, where a superframe includes an integer number of check frames;

The check frame detecting unit 1103 is configured to perform error detection or error correction on the service stream coded code block according to the check bits in each check code block in the check frame, where one super frame includes an integer number of check frames;

a code block obtaining unit 1104, configured to remove a check bit in the check code block to obtain a service stream coded block;

The decoding unit 1105 is configured to decode the service stream coded code block to obtain decoded service data.

In the embodiment of the present invention, the codeword identification unit 1101 can implement the WORD ALIGNMENT mechanism in a plurality of manners to determine the boundary of the superframe header. For the specific implementation process, reference may be made to the foregoing description, and details are not described herein again.

Corresponding to the check frame generation mechanism, the check frame detecting unit 1103 includes: a check bit generating subunit and a matching subunit (not shown), wherein the check bit generating subunit is configured to acquire the previous school Detecting a payload in the frame, and generating a check bit of the service stream coded code block in the previous check frame according to the payload; a matching subunit, configured to match the previous school generated by the check bit generation subunit In the frame inspection, the check bit of the service stream coding code block and the check bit in the current check frame, and when the matching result is the same, it is determined that the service flow code block in the previous school risk frame is correctly transmitted.

In addition, the general public radio interface service receiving apparatus of the embodiment of the present invention further provides a LOS mechanism. To this end, the general public radio interface service receiving apparatus may further include:

The indicating unit 1106 is configured to: when the codeword identifying unit 1101 detects that the check code block in the check frame is in an unsynchronized state in a superframe, indicate an LOS state; and identify the codeword The unit 1101 detects that the check code block in the check frame is in a synchronization state in one super frame, and indicates that when the check frame detecting unit 1103 detects that no check bit does not match in the super frame, The LOS status is terminated. The universal public radio interface service receiving apparatus in the embodiment of the present invention can correctly identify the service code stream transmitted by the CPRI interface by using an efficient line coding mechanism, and ensures the correctness of the received data.

The embodiments of the present invention have been described in detail above, and the present invention has been described with reference to the specific embodiments thereof. The description of the above embodiments is only for facilitating understanding of the method and device of the present invention. Meanwhile, for those skilled in the art, The present invention is not limited by the scope of the present invention.

Claims

Rights request

A general public radio interface service sending method, which is characterized in that:

Forming a plurality of calibration frames into one superframe, and identifying a frame header of the superframe;

The superframe after the identity is sent.

The method according to claim 1, wherein the service stream coded code block is a 32B/34B coded code block, and the check coded code block is a 32B/35B coded code block, or the service flow. The coded code block is 36B/40B coded code block without a check bit, and the check code block is a 36B/40B code block.

The method according to claim 2, wherein the method further comprises: generating a 32-bit check digit by using a polynomial g ^ ^ + ^ + ^ + + + +l, wherein the X represents shift The bit register, power, represents the position of the shift register.

4. The method of claim 1 wherein:

Adding a check digit to the service stream coding code block to generate a check code block, and forming a plurality of check code blocks into a check frame includes:

For the i-th check frame, where i is an integer greater than 1, the following processing is performed on the service stream coded block in the i-th check frame in sequence:

Inserting each bit in the parity bit generated for the i-1th check frame into the service stream coding code block; according to the RD polarity of all the coded code streams and the code stream in the current service stream to be coded The RD polarity of the part of the payload is encoded by the service stream to encode the service stream code block to be encoded to obtain the service stream code block; and the obtained service stream is coded and interleaved into the obtained service stream. The check bits in the coded block form a check code block; update the RD polarity of all coded code streams; and form the generated plurality of check code blocks into an i-th check frame.

The method according to claim 1, wherein the check digit is: an FEC check bit, or a CRC check bit, or a parity bit.

6. The method according to claim 4, wherein all of the encoded code streams are 32B/35B coded code streams, and the service flow code is 32B/35B coded.

7. The method according to claim 4, wherein all of the encoded code streams are 36B/40B coded code streams, and the service flow code is 36B/40B coded.

The method according to any one of claims 1 to 7, wherein the identifying the frame header of the super frame comprises:

Identifying the frame header of the superframe with the control word K28.5, and

If the number of 1s in all transmitted codes is greater than or equal to 0, the codeword of control word K28.5 is mapped to "1100000101";

If the number of 1s in all transmitted codes is less than 0, the code word of control word K28.5 is mapped to "0011111010".

A general public radio interface service receiving method, characterized in that:

Identifying superframe boundaries based on superframe header characteristics;

Decoding the service stream coded block to obtain decoded service data.

10. The method according to claim 9, wherein the received service code stream is

32B/35B coded stream, or 36B/40B coded stream.

The method according to claim 10, wherein the identifying the superframe boundary according to the superframe header feature comprises: identifying a superframe boundary of the 32B/35B encoded code stream by detecting a k28.5 character.

The method according to claim 10, wherein the identifying the superframe boundary according to the superframe header feature comprises: identifying a superframe boundary of the 36B/40B encoded code stream by detecting 10 characters.

13. The method according to claim 9, wherein the check code block is

a 32B/35B coded code block, wherein the service stream coded code block is a 32B/34B coded code block;

The performing codeword synchronization on the received service code stream includes:

The word boundary is determined by the state machine, and the state machine includes the following states: a codeword unsynchronized state, a codeword character detection state, a codeword synchronization state, a codeword synchronization error state; In the unsynchronized state of the codeword, a predetermined bitstream pattern is searched from the received service code stream into the codeword character detection state by using a window, the predetermined bitstream pattern comprising: a superframe frame header bitstream, and 6B valid characters in the 5B/6B code mapping table;

In the codeword character detection state, continuing to detect data subsequent to the bitstream pattern, if the subsequent data of the bitstream pattern is a legal code, and the number of the legal codes reaches a first predetermined value, the entry code a word synchronization state; if the subsequent data of the bitstream pattern is an illegal code, returning to a codeword unsynchronized state; the legal code indicating that the data is a superframe frame header bitstream k28.5, or 5B/6B encoding Mapping a 6B valid character in the table; the illegal code indicating that the data is not a superframe header bitstream k28.5, and is not a 6B valid character in the 5B/6B encoding mapping table;

In the codeword synchronization state, if the subsequently received data is a legal code, the codeword synchronization state is maintained; if the subsequently received data is an illegal code, the codeword synchronization error state is entered;

In the codeword synchronization error state, if the number of received illegal codes reaches the second predetermined value, the codeword is not synchronized; if the number of received legal codes reaches the third predetermined value, the illegal code will be received. The number is reduced by 1; when the number of illegal codes received is reduced to 0, the codeword synchronization state is entered; the boundary is not found;

If the state machine is in a codeword synchronization state or a codeword synchronization error state, it is determined that the superframe boundary has been found.

The method according to claim 9, wherein the check code block is a 32B/35B code block, and the service stream code block is a 32B/34B code block;

The word boundary is determined by a state machine, and the state machine includes the following states: a codeword unsynchronized state, a codeword character detection state, and a codeword synchronization state;

In the unsynchronized state of the codeword, a predetermined bitstream pattern is searched from the received service code stream by windowing, and enters a codeword character detection state, where the predetermined bitstream pattern includes: a superframe frame header bitstream, 6B valid characters in the 5B/6B code mapping table;

In the codeword character detection state, the data subsequent to the bitstream pattern is continuously detected, if the data subsequent to the bitstream pattern is continuously detected as a legal code, and the number of the predetermined bitstream pattern reaches the first Four predetermined values, then enter the codeword synchronization state; if the bitstream pattern is subsequent If the data is an illegal code, returning to the unsynchronized state of the codeword; the legal code indicating that the data is a superframe header bitstream, or a 6B valid character in a 5B/6B coding mapping table; The data is not a superframe header bit stream, and is not a 6B valid character in the 5B/6B code mapping table;

In the codeword synchronization state, if the subsequently received data is a legal code, the codeword synchronization state is maintained; if the number of subsequent received data is the fifth predetermined value, the codeword is not synchronized. ; the boundary was not found;

The method according to claim 14, wherein the fourth predetermined value is 64 and the fifth predetermined value is 16.

The method according to claim 9, wherein the error detection or error correction of the service stream coded code block according to the check bits in each check code block in the check frame includes:

Obtaining a payload in the previous check frame, and generating a check bit of the service stream coded block in the previous check frame according to the payload;

If the check bit generated by the traffic stream code block in the previous check frame is the same as the check bit transmitted in the current check frame, it is determined that the service stream code block in the previous check frame is correctly transmitted.

The method according to any one of claims 13 to 16, wherein the method further comprises:

If it is detected in a superframe that the 32B/35B coded code block in the check frame is in an unsynchronized state, or in a superframe, at least 16 check bits in the check frame and its corresponding service flow If the parity bits of the coded code block do not match, the LOS state is indicated;

18. A general public radio interface service sending apparatus, comprising:

a check frame generating unit, configured to add a check bit in the service stream coded code block to obtain a check code block, and the plurality of check code blocks form a check frame, and the service stream code block in the current check frame The check bit added in is the check digit of the service stream coding code block in the previous check frame; a superframe generating unit, configured to form a plurality of check frames into a super frame, and identify a frame header of the super frame; and a sending unit, configured to send the identified super frame.

The device according to claim 18, wherein the service stream coded code block is a 32B/34B coded code block, and the check coded code block is a 32B/35B coded code block; And a check bit generating unit, configured to generate a 32-bit check bit by using a polynomial g ^ ^ + ^ + W + +l, wherein the X represents a shift register, and the power represents a position of the shift register.

The device according to claim 18, wherein the service stream coded code block is a coded block of 36B/40B without a check bit, and the check code block is a 36B/40B code block. .

21. Apparatus according to claim 18 wherein:

The superframe generating unit is specifically configured to identify a frame header of the superframe by using a control word K28.5, and if the number of 1s in all the transmitted codes is greater than or equal to 0, The codeword of the control word K28.5 is mapped to "1100000101". If the number of 1s in all the transmitted codes is less than 0, the codeword of the control word K28.5 is mapped to "0011111010".

22. A universal public radio interface service receiving apparatus, comprising:

a check frame detecting unit, configured to perform error detection or error correction on the service stream coded code block according to the check bit in each check code block in the check frame;

a code block obtaining unit, configured to remove a check bit in the check code block to obtain a service stream code block;

And a decoding unit, configured to decode the service stream coded code block to obtain decoded service data.

The apparatus according to claim 22, wherein the check frame detecting unit comprises:

a check bit generating subunit, configured to obtain a payload in a previous check frame, and generate a check bit of the service stream coded code block in the previous check frame according to the effective load;

a matching sub-unit, configured to match a check bit of the service stream coding code block in the previous check frame generated by the check bit generation sub-unit and a check bit in the current check frame, and when the matching result is the same, Before determining The traffic stream code block in a check frame is transmitted correctly.

The device according to claim 22 or 23, wherein the device further comprises: an indication unit, configured to detect a calibration in the verification frame in a superframe in the codeword identification unit When the coded block is in an unsynchronized state, or in a superframe, at least 16 check bits in the check frame do not match the check bits of the corresponding service stream code block, indicating the LOS state; The codeword identification unit detects that the check code block in the check frame is in a synchronization state within one super frame, and the check frame detection unit detects that no check bit does not match in the super frame. When the LOS status is terminated.