CN103004123B - Method of adapting fec codeword to physical resource block, method of synthesizing fec codeword and system thereof - Google Patents

Abstract

The present invention is applicable to the communication field, and provides a method for adapting FEC codewords to physical resource blocks, a method and system for synchronizing FEC codewords, and the method for adapting FEC codewords to physical resource blocks includes: Within, the first physical resource block allocated to the user is the starting position of the FEC codeword and starts to carry data. If the remaining part of the last physical resource block allocated to the user is not enough to carry an FEC codeword, the remaining part is filled Invalid data or according to the length of the remaining part, shorten the FEC code word as a shortened FEC code word, and the FEC code word adopts a fixed length. The present invention reduces the number of codewords supported by the system and the complexity of the system, does not need to add an additional FEC boundary indication, and when a MAP reception error occurs, the FEC can periodically recover and set the boundary, and the remaining part of the last physical resource block is shortened. FEC codes are used to carry useful data, which improves resource utilization.

Description

FEC code word to physical resource block adaptation method, FEC code word synchronization method and system

technical field

The present invention relates to the communication field, and in particular to an adaptation method from an FEC codeword to a physical resource block, a method and a system for synchronizing an FEC codeword.

Background technique

EOC (Ethernet over Cable) refers to the technical term for transmitting Ethernet data on coaxial cables. Now there are various EOC technical solutions in the industry, with different scales and maturity levels. They are mainly divided into two types: passive baseband EOC and active modulation EOC. The passive baseband EOC system transmits data through two-to-four conversion and coupling of data signals. It is characterized by relatively simple and cheap equipment, but poor adaptability to the network, and cannot be transmitted through equipment such as active amplifiers and passive branch distributors. Only applicable to star centralized distribution network; active modulation EOC transmits data after modulation and demodulation of data, it can transparently transmit amplifiers and branch distributors, and can be applied to star network and tree network Networks (such as addressable systems in the network) also have good adaptability.

EoC technology adopts a point-to-multipoint user network topology, and uses the original coaxial cable of radio and television to realize full-service access of data, voice and video. A typical active modulation EOC system consists of head end, terminal, coaxial distribution network and other parts. The head end is generally placed at the position of the optical node to distribute upper-layer Ethernet data and aggregate terminal equipment; the terminal is placed in the user's home as a home terminal modem to access the user's computer or interactive set-top box; the coaxial distribution network is from the CATV (Cable Television, wired TV) Optical node position to the user's home network, in addition to coaxial cables, also includes active amplifiers, EOC jumpers, branch distributors and other equipment.

PON (Passive Optical Network, Passive Optical Network) technology is a point-to-multipoint optical fiber transmission and access technology, downlink adopts broadcast mode, uplink adopts time division multiple access mode, and can flexibly form tree, star, bus Type and other topological structures, no node equipment is required at the optical branch point, only a simple optical splitter needs to be installed.

The tree-type topology structure is a commonly used topology structure in the existing passive optical network, which includes the optical line terminal (Optical Line Terminal, OLT) on the office side, the optical network unit (Optical Network Unit, ONU) on the user side, or the Terminal (Optical Network Terminal, ONT) and optical distribution network (optical distribution network, ODN). The so-called "passive" means that the ODN does not contain any active electronic devices and electronic power supplies, and is all composed of passive devices such as optical splitters (Splitter), so its management and maintenance costs are relatively low.

In the PON system, the transmission direction from the OLT to the ONU is the downlink direction, and the TDM method is adopted, that is, the downlink data transmission is continuous, and the OLT continuously broadcasts information to each ONU, and each ONU chooses its own data to receive.

The transmission from ONU to OLT is in the uplink direction, using TDMA mode, that is, the uplink data transmission is bursty, different ONUs occupy different uplink time slots, and multiple ONUs share the uplink through time division multiplexing. There is a guard time interval between each uplink time slot to avoid collisions.

In order to ensure that the uplink data will not collide, the uplink transmission needs to use ranging technology to measure the loop delay of the data signal sent from the OLT downlink to the uplink received, and perform delay compensation accordingly to ensure that the uplink signal of each ONU is within the common After the fibers are merged, they are inserted into the specified time slots, and there is no collision between them, and the gap should not be too large.

The IEEE organization formally established the 802.3ah working group in 2001, also known as the EFM working group or Ethernet for the First Mile (EFM). into the standardization work of the technology EPON (Ethernet Passive Optical network, Ethernet Passive Optical Network), and officially promulgated in June 2004. EPON technology inherits the low cost and ease of use of Ethernet and the high bandwidth of optical network, and has very good cost performance. After the official release of the EPON international standard, the current EPON industry chain has become increasingly mature and has been deployed on a large scale.

With the popularity of network applications, various emerging enhanced services have accelerated the increase in bandwidth requirements. The IEEE standard organization began to consider the standardization of 10G EPON, and formally established the IEEE 802.3av working group in September 2006. The goal of the IEEE802.3av working group is to define a 1Gbps uplink/10Gbps downlink asymmetric network architecture and a 10Gbps uplink/10Gbps downlink symmetric network architecture and meet the physical layer bit error rate not greater than 10-12 point-to-multipoint optical access technology, At the same time, the coexistence of 1G EPON system and 10G EPON system should also be considered.

EPOC (EPON over COAX), that is, to introduce mature EPON technology into COAX (coaxial cable, coaxial cable), that is, to realize EPON MAC (Media Access Control, media access control) on CNU (Coax Network Unit, coaxial network unit) ), the OLT of EPON can directly control the CNU of the copper domain. From the perspective of the OLT, the difference between the CNU and the ONU of EPON is only in the physical layer. In this way, the CMC (COAX Media Converter, coaxial cable media converter) is simplified compared with the previous EOC nodes, and the OLT can manage the CNU end-to-end.

In the EPOC system, CMC is used as a medium conversion device between coaxial and optical. At present, there are many implementation schemes for CMC:

(1) No-MAC scheme:

Only the physical layer is defined on the CMC, and the CMC only performs the conversion of the physical medium, without the MAC function; the time slice allocation of the Coax segment and the fiber segment is managed by the OLT;

(2) 1.5MAC scheme:

There is a MAC layer definition on the CMC (IND), but the MAC layer of the CMC does not allocate bandwidth to the CNU in the copper domain, but analyzes and translates it into the time corresponding to coax according to the bandwidth allocation information of the OLT;

(3) 2MAC scheme:

The PON and EOC segments adopt independent bandwidth scheduling, and the intermediate device CMC independently completes the bandwidth allocation of the EOC segment.

FEC (Forward Error Correction, Forward Error Correction) coding means that the sending end sends codes that can correct errors, and the receiving end automatically corrects errors that occur during transmission according to the received codes and coding rules. FEC coding is widely used in optical transmission systems, which can improve the performance of optical networks, such as increasing the transmission distance of optical communication systems, reducing the transmission power of optical transceivers, and reducing receiver sensitivity.

RS (reed solomon, Reed Solomon) code is a kind of FEC coding, which is suitable for correcting such burst errors. The main parameters of an RS code that can correct T error symbols are as follows:

(1) code length N=2m-1 code elements;

(2) supervise code element number N-K=2T code element;

(3) Minimum code distance dmin=2T+1 code elements.

Among them, m represents the number of bits of each symbol, such as RS (255, 239) used in GPON (gigabit-capable pon), m=8, and each symbol is a byte.

In the point-to-multipoint system of OFDMA (Orthogonal frequency division multiple access, Orthogonal Frequency Division Multiple Access), the central office is responsible for allocating the time-frequency block resources of each user in the uplink and downlink directions. The field (such as MAP (mapping) message) informs the user of its uplink and downlink time-frequency block information. In the downlink direction, the user receives and extracts data in its own time-frequency block according to the information indicated by the MAP; in the uplink direction, the user sends data in its own time-frequency block according to the information indicated by the MAP.

OFDMA systems in the prior art, such as WIMAX (Worldwide Interoperability for Microwave Access, Global Microwave Interconnection Access), LTE ((Long Term Evolution, Long Term Evolution), etc., the size of the FEC codeword and the physical resource block of OFDMA, that is, two-dimensional time Frequency resource blocks, also called PRBs (Physical Resource Blocks, physical resource blocks), are equal in size, or are integer multiples of PRBs.

This prior art OFDMA system has the following disadvantages:

(1) Limited by the size of PRB, the code length defined by WIMAX and LTE is relatively small, no more than 100 bytes, and the coding gain is limited;

(2) WIMAX and LTE systems need to define and support more codewords to apply to PRBs of different sizes;

(3) The modulation method of each subcarrier inside the PRB of the WIMAX and LTE systems is the same, and the number of modulation bits is even, while the modulation method of each subcarrier inside a PRB of the EPOC system is different, and the supported debugging There are more ways. If the size of the FEC codeword is equal to the PRB size of OFDMA, more FEC codewords will need to be defined, which will bring complexity to the system.

In addition, the 10G EPON of the prior art designs a special 64/66B pattern for the FEC codeword, and defines a synchronization state machine at the receiving end to obtain codeword synchronization by searching the synchronization pattern.

The 10G EPON of the prior art has the following disadvantages: the codeword synchronization method of 10G EPON is suitable for continuous systems, but not suitable for burst systems, such as OFDMA scenarios, that is, the receiving end of each burst needs to first perform FEC codeword synchronization ( Find the codeword boundary), may need to occupy additional resources to synchronize.

Contents of the invention

The embodiment of the present invention provides a method for adapting FEC codewords to physical resource blocks, aiming to solve the problems in the prior art that due to the size of FEC codewords and the correspondence between physical resource blocks, the coding gain is limited and many definitions and supports are required. Codewords are applicable to physical resource blocks of different sizes and problems with complex systems.

In one aspect, a method for adapting a forward error correction (FEC) codeword to a physical resource block is provided, the method comprising: within an agreed time period, the first physical resource block allocated to a user is the first physical resource block of the FEC codeword The starting position starts to carry data. If the remaining part of the last physical resource block allocated to the user is not enough to carry an FEC codeword, the remaining part is filled with invalid data or the FEC codeword is shortened according to the length of the remaining part. A codeword, the FEC codeword adopts a fixed length.

In another aspect, a method for adapting FEC codewords in a forward error correction mode to physical resource blocks is provided, the method comprising:

In the agreed time period, according to the mapping MAP management message in the current period, it indicates the processing mode of the first physical resource block allocated to the user or the last physical resource block allocated to the user in the current period.

In another aspect, a method for synchronizing a FEC code word in a forward error correction mode is provided, the method comprising:

Receive physical frame;

Detecting the physical frame to obtain frame synchronization;

Analyzing the broadcast mapping MAP message to determine the physical resource block allocated to each user;

According to the agreed rules, determine the way of delimiting codewords;

The FEC code word is extracted from the allocated physical resource block according to the fixed code length, and the remaining part of the last physical resource block in the agreed time period is correspondingly processed according to the agreed rules.

In another aspect, a forward error correction mode FEC codeword synchronization system is provided, the system comprising:

A receiving module, configured to receive a physical frame;

A detection module, configured to detect the physical frame received by the receiving module to obtain frame synchronization;

The parsing module is used to parse the broadcast mapping MAP message, and determine the physical resource block allocated to each user;

A determination module, configured to determine the codeword delimitation method according to the agreed rules; and

The extracting module is used to extract the FEC code word according to the fixed code length from the allocated physical resource block, and perform corresponding processing on the remaining part of the last physical resource block in the agreed time period according to the agreed rules.

Since the FEC codeword in the FEC frame provided by the embodiment of the present invention adopts a fixed length, the number of codewords supported by the system and the system complexity are reduced; in addition, since the last physical resource block allocated to the user within the agreed time period If the remaining part of the physical resource block is not enough to carry an FEC codeword, the FEC codeword is shortened according to the length of the remaining part, so that the remaining part of the last physical resource block uses the shortened FEC code to carry useful data, so The resource utilization rate is improved; in addition, since the starting position of the FEC codeword is aligned with the position of the first physical resource block allocated to the user within the agreed time period, there is no need to add an additional FEC boundary indication, and when the MAP receives FEC can periodically recover setting boundaries in case of errors.

Description of drawings

FIG. 1 is a schematic diagram of PRBs of an OFDMA system in Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of PRBs allocated to a certain user within an agreed time length in Embodiment 1 of the present invention.

FIG. 3 and FIG. 4 are schematic diagrams of a method for adapting an FEC codeword to a PRB according to Embodiment 1 of the present invention.

Fig. 5 is a schematic diagram of symbols allocated to a certain user within an agreed time period in Embodiment 2 of the present invention.

FIG. 6 and FIG. 7 are schematic diagrams of the FEC codeword-to-symbol adaptation method provided by Embodiment 2 of the present invention.

FIG. 8 is a flow chart of a method for synchronizing FEC codewords provided by Embodiment 4 of the present invention.

Fig. 9 is a schematic diagram of OFDMA physical frame structure.

Fig. 10 is a schematic diagram of a MAP message.

FIG. 11 and FIG. 12 are schematic diagrams of the manner in which the PRB carries the FEC codeword when the user does not reset the FEC codeword boundary in the current period.

FIG. 13 is a block diagram of functional modules of the FEC codeword synchronization system provided by Embodiment 5 of the present invention.

FIG. 14 is a flowchart of a method for adapting a MAC frame to a physical frame according to Embodiment 6 of the present invention.

FIG. 15 is a block diagram of functional modules of a MAC frame-to-physical frame adaptation system provided by Embodiment 7 of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, and are not intended to limit the present invention.

Embodiment one:

The physical resource block of the OFDMA system, that is, the two-dimensional time-frequency resource block, also known as PRB, is the minimum resource allocation granularity. Each PRB can occupy one or more symbols on the time axis, and occupy one or more symbols on the frequency axis. 1 or more subcarriers. As shown in Figure 1, the number of PRBs that can be used in the available frequency band of the OFDMA system is N+1, where N is a natural number.

Assume that a predetermined time length, that is, a predetermined time period, is allocated to a user within the predetermined time length as shown in Figure 2. PRB, where the meaning of PRB (i, j) is that i represents the i-th time unit, j represents the j-th PRB at the i-th moment, where i and j are both natural numbers.

Referring to FIG. 3, the FEC codeword-to-PRB adaptation method provided by Embodiment 1 of the present invention includes: within the agreed time period, the first PRB allocated to the user is the starting position of the FEC codeword and starts to carry data, If the remaining part of the last PRB allocated to the user is not enough to bear one FEC codeword, the remaining part is filled with invalid data, wherein the FEC codeword adopts a fixed length. As shown in Fig. 3, the remaining part of PRB (4, 3) is not enough for a codeword size.

The agreed time period may be a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system, such as one or more symbols.

Please refer to FIG. 4. In the FEC codeword-to-PRB adaptation method provided in Embodiment 1 of the present invention, within the agreed time period, if the remaining part of the last PRB allocated to the user is not enough to carry an FEC codeword, then According to the length of the remaining part, the FEC codeword may be shortened to improve resource utilization.

Taking FEC code as RS code as an example, if the system adopts RS(255,239) code with fixed code length, N in RS(N,K) means that the encoded length of the RS code is N bytes, and K is the length of N bytes. The length of the information byte, N-K bytes are check bytes. For the remaining part of the last PRB allocated to the user within the agreed time period, if it is smaller than the fixed FEC code length, it can be coded with the code length of the actual length. If there are 200 bytes remaining, RS(200,184) can be used.

Since the FEC codeword in the FEC frame provided by Embodiment 1 of the present invention adopts a fixed length, thereby reducing the number of codewords supported by the system and system complexity; If the remaining part is not enough to carry a FEC codeword, then according to the length of the remaining part, the FEC codeword is shortened to the FEC codeword, so that the remaining part of the last PRB uses the shortened FEC code to carry useful data, thus improving resource utilization. Utilization rate; In addition, since the starting position of the FEC codeword is aligned with the position of the first PRB allocated to the user within the agreed time period, there is no need to add an additional FEC boundary indicator, and the FEC can be cycled when a MAP reception error occurs. recovery sets boundaries.

Embodiment two:

The physical resource block of the OFDM (Orthogonal frequency division multiplexing) system, that is, the symbol (symbol), is used as the minimum resource allocation granularity, and only one user occupies all the frequency bands at a time.

Assume that there is an agreed time period, that is, an agreed time period, within the agreed time period, a certain user is assigned a symbol as shown in FIG. 5 .

Referring to FIG. 6, the FEC codeword-to-symbol adaptation method provided by Embodiment 2 of the present invention includes: within the agreed time period, the first symbol allocated to the user is the starting position of the FEC codeword and starts to carry data, If the remaining part of the last symbol allocated to the user is not enough to bear one FEC codeword, the remaining part is filled with invalid data, wherein the FEC codeword adopts a fixed length. As shown in Figure 6, the remaining part of symbol 4 is not enough for a codeword size.

The agreed time period may be a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system, such as one or more symbols.

Please refer to FIG. 7. In the FEC codeword-to-symbol adaptation method provided in Embodiment 2 of the present invention, in the agreed time period, if the remaining part of the last symbol allocated to the user is not enough to carry an FEC codeword, then According to the length of the remaining part, the FEC codeword may be shortened to improve resource utilization.

Taking FEC code as RS code as an example, if the system adopts RS(255,239) code with fixed code length, N in RS(N,K) means that the encoded length of the RS code is N bytes, and K is the length of N bytes. The length of the information byte, N-K bytes are check bytes. For the remaining part of the last symbol allocated to the user within the agreed time period, if it is less than the fixed FEC code length, it can be encoded with the code length of the actual length. If there are 200 bytes remaining, RS(200,184) can be used.

Since the FEC codeword in the FEC frame provided by Embodiment 2 of the present invention adopts a fixed length, thereby reducing the number of codewords supported by the system and system complexity; If the remaining part is not enough to carry an FEC codeword, then according to the length of the remaining part, shorten the FEC codeword to use the shortened FEC codeword, so that the remaining part of the last symbol uses the shortened FEC code to carry useful data, thus improving resource utilization. Utilization rate; In addition, since the starting position of the FEC codeword is aligned with the position of the first symbol allocated to the user within the agreed time period, there is no need to add an additional FEC boundary indicator, and the FEC can be cycled when a MAP reception error occurs. recovery sets boundaries.

Embodiment three:

The method for adapting FEC codewords to physical resource blocks provided in Embodiment 3 of the present invention includes:

In the agreed time period, according to the MAP management message in the current period, indicate the processing mode of the first physical resource block allocated to the user or the last physical resource block allocated to the user in the current period. The agreed time period is a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system.

Wherein, the processing method of indicating the first physical resource block allocated to the user in the current period includes: indicating whether to reset the codeword boundary of the FEC for the first physical resource block, if the FEC boundary is reset, the FEC codeword is aligned at the first A physical resource block position, otherwise a fixed-length codeword is used, that is, a fixed-length codeword is jointly carried at the end of the previous cycle and the front of the current cycle.

Wherein, the processing method of indicating the last physical resource block allocated to the user in the current period is specifically: indicating the processing method when the remaining part of the last physical resource block is not enough to carry a fixed-length FEC codeword, and the processing method includes : The remaining part is filled with invalid data, the FEC codeword is shortened according to the length of the remaining part, or the end of the previous period and the front of the current period jointly carry a fixed-length codeword. The shortened FEC codeword is a Reed-Solomon RS codeword.

In Embodiment 3 of the present invention, the physical resource block is a two-dimensional time-frequency resource block (ie, PRB) in an OFDMA system or a symbol in an OFDM system.

Embodiment four:

Referring to FIG. 8, the FEC codeword synchronization method provided in Embodiment 4 of the present invention includes the following steps:

S101. Receive a physical frame;

In Embodiment 4 of the present invention, for an OFDMA frame, each physical frame includes Np payload (payload) symbols, and TS (Training Sequence, training sequence) is used for frame delimitation and channel training, as shown in FIG. 9 .

S102. Detect the physical frame, and acquire frame synchronization;

In Embodiment 4 of the present invention, for an OFDMA frame, what is detected is the TS in the physical frame.

S103, analyzing the broadcast MAP message, and determining the physical resource block allocated to each user;

In Embodiment 4 of the present invention, the physical resource block is a two-dimensional time-frequency resource block (ie, PRB) in an OFDMA system or a symbol in an OFDM system.

In Embodiment 4 of the present invention, as shown in FIG. 10 , the management message including the MAP may occupy a certain PRB position, and the carrying mode of the MAP is as follows: the first one or more PRBs of the starting symbol are occupied for carrying, indicating PRB resource allocation of the entire MAP cycle (one or more symbols).

S104. Determine the manner of delimiting the code word according to the agreed rules;

In Embodiment 4 of the present invention, the agreed rule is: within the agreed time period, the first physical resource block of the user is the starting position of the FEC code word. Therefore, the receiving end will realign the boundary of the FEC codeword every cycle.

The agreed time period may be a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system, such as one or more symbols.

S105. Extract the FEC code word according to the fixed code length from the allocated physical resource block, and perform corresponding processing on the remaining part of the last physical resource block in the agreed time period according to the agreed rules.

For example, if the agreed rule is that the remaining part of the last physical resource block of the agreed time period is filled with invalid data, the data carried by the remaining part of the last physical resource block is discarded; The remaining part of the last physical resource block adopts the shortened code mode, and then the code word of the length of the remaining part of the last physical resource block is extracted.

In the fourth embodiment of the present invention, in step S104, according to the agreed rules, the manner of determining the codeword delimitation may also be: indicating whether to reset the codeword boundary of the FEC in the current cycle through a MAP management message. Taking the agreed time period equal to the MAP indication period as an example, there is a specific bit field in the MAP management message to indicate whether to reset the code word boundary of the FEC in the current period.

If the MAP management message indicates that the user does not reset the code word boundary of the FEC in the current period, the manner in which the physical resource block carries the FEC code word is shown in FIG. 11 and FIG. 12 . As shown in Figure 12, the FEC codeword is carried across PRBs of two cycles, and there is no padding or shortening of the FEC codeword at the end of the previous cycle.

In step S105, according to the agreed rules, the corresponding processing for the remaining part of the last physical resource block in the agreed time period may specifically be as follows:

If the MAP management message indicates that the user does not reset the codeword boundary of FEC in the current period, the FEC codeword is carried across the physical resource blocks of two periods, and for the remaining part of the last physical resource block of the previous agreed time period and the following In the first physical resource block of an agreed time period, continue to extract the FEC code word according to the fixed code length.

In the FEC codeword synchronization method provided in Embodiment 4 of the present invention, since the codeword demarcation method is determined according to the agreed rules, the FEC codewords are extracted from the allocated physical resource blocks according to the fixed code length, and the agreed time is determined according to the agreed rules. The remaining part of the last physical resource block of the period is processed accordingly, so there is no need to add an additional FEC boundary indication, and the FEC can periodically recover and set the boundary when a MAP reception error occurs.

Embodiment five:

Referring to FIG. 13 , the FEC codeword synchronization system provided by Embodiment 5 of the present invention includes: a receiving module 11 , a detecting module 12 , an analyzing module 13 , a determining module 14 and an extracting module 15 . in

The receiving module 11 is used to receive the physical frame;

In Embodiment 5 of the present invention, for an OFDMA frame, each physical frame includes Np payload (payload) symbols, and TS (Training Sequence, training sequence) is used for frame delimitation and channel training, as shown in FIG. 9 .

The detection module 12 is used to detect the physical frame received by the receiving module 11 to obtain frame synchronization;

In the fifth embodiment of the present invention, for the OFDMA frame, what is detected is the TS in the physical frame.

Parsing module 13 is used for parsing the MAP message of broadcast, determines the physical resource block allocated to each user;

In Embodiment 5 of the present invention, the physical resource block is a two-dimensional time-frequency resource block (ie, PRB) in an OFDMA system or a symbol in an OFDM system.

In Embodiment 5 of the present invention, as shown in FIG. 10 , the management message including the MAP may occupy a certain PRB position. An example of the carrying mode of the MAP is as follows: the first one or more PRBs of the starting symbol are occupied for carrying, indicating PRB resource allocation of the entire MAP cycle (one or more symbols).

Determining module 14 is used for determining the mode of codeword delimitation according to agreed rules;

In Embodiment 5 of the present invention, the agreed rule is: within the agreed time period, the first physical resource block of the user is the starting position of the FEC code word. Therefore, the receiving end will realign the boundary of the FEC codeword every cycle.

The agreed time period may be a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system, such as one or more symbols.

The extracting module 15 is used to extract the FEC code word according to the fixed code length from the allocated physical resource block, and perform corresponding processing on the remaining part of the last physical resource block in the agreed time period according to the agreed rules.

For example, if the agreed rule is that the remaining part of the last physical resource block of the agreed time period is filled with invalid data, the data carried by the remaining part of the last physical resource block is discarded; The remaining part of the last physical resource block adopts the shortened code mode, and then the code word of the length of the remaining part of the last physical resource block is extracted.

In Embodiment 5 of the present invention, the determining module 14 may specifically be used to indicate whether to reset the codeword boundary of the FEC in the current cycle through a MAP management message. Taking the agreed time period equal to the MAP indication period as an example, there is a specific bit field in the MAP management message to indicate whether to reset the code word boundary of the FEC in the current period.

If the MAP management message indicates that the user does not reset the code word boundary of the FEC in the current period, the manner in which the physical resource block carries the FEC code word is shown in FIG. 11 and FIG. 12 . As shown in FIG. 12 , the FEC codeword is carried across the physical resource blocks of two periods, and there is no padding or shortening of the FEC codeword at the end of the previous period.

The extracting module 15 performs corresponding processing on the remaining part of the last physical resource block in the agreed time period according to the agreed rules, which may specifically be as follows:

If the MAP management message indicates that the user does not reset the codeword boundary of FEC in the current period, the FEC codeword is carried across the physical resource blocks of two periods, and for the remaining part of the last physical resource block of the previous agreed time period and the following In the first physical resource block of an agreed time period, continue to extract the FEC code word according to the fixed code length.

In the FEC codeword synchronization system provided by Embodiment 5 of the present invention, since the codeword demarcation method is determined according to the agreed rules, the FEC codewords are extracted from the allocated physical resource blocks according to the fixed code length, and the agreed time is determined according to the agreed rules. The remaining part of the last physical resource block of the period is processed accordingly, so there is no need to add an additional FEC boundary indication, and the FEC can periodically recover and set the boundary when a MAP reception error occurs.

Embodiment six:

Referring to FIG. 14 , a method for adapting a MAC frame to a physical frame provided by Embodiment 6 of the present invention includes the following steps:

S201. Add a frame delimiter to the Ethernet frame, specifically:

Place an S symbol at the head of the Ethernet frame;

When there is no subsequent Ethernet frame, the idle bits are filled into the physical resource block; that is, a T symbol is first placed at the end of the previous Ethernet frame, and the T symbol is used to indicate that the subsequent is idle filling;

In Embodiment 6 of the present invention, the physical resource block is a two-dimensional time-frequency resource block (ie, PRB) in an OFDMA system or a symbol in an OFDM system.

S202. Use 64/66B encoding rules to encode the Ethernet frame; S203. Perform FEC encoding on the 64/66B encoded Ethernet frame and insert a check digit;

Specifically: perform RS (255,239) encoding for every 29 66B blocks, and insert 2 parity check blocks of 66B blocks as a FEC code word, that is, 31 66B blocks;

S204. Adapt the FEC-encoded frame to the physical resource block specified for the user.

In Embodiment 6 of the present invention, step S204 is specifically:

Within the agreed time period, the first physical resource block allocated to the user is the starting position of the FEC codeword and starts to carry data. If the remaining part of the last physical resource block allocated to the user is not enough to carry an FEC codeword, Then the remaining part is filled with invalid data or the FEC codeword is shortened according to the length of the remaining part, wherein the FEC codeword adopts a fixed length.

The agreed time period may be a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system, such as one or more symbols.

Taking the agreed time period as the MAP indication period as an example, the FEC-encoded frame carries the FEC-encoded frame from the boundary of the first physical resource block according to the number of physical resource blocks allocated to it to carry data in the current MAP period. , if the last physical resource block is not enough to carry an FEC codeword, the remaining part is filled with invalid data and is not used to carry the FEC encoded frame.

Embodiment seven:

Please refer to FIG. 15 , a MAC frame-to-physical frame adaptation system provided by Embodiment 7 of the present invention. The system includes:

Add module 21, be used for adding frame delimiter for Ethernet frame;

Encoding module 22, for adopting 64/66B encoding rule to encode this Ethernet frame;

The FEC encoding module 23 is used for performing FEC encoding and inserting check digits;

The adaptation module 24 is configured to adapt the FEC encoded frame to the physical resource block specified for the user.

In Embodiment 7 of the present invention, the physical resource block is a two-dimensional time-frequency resource block (ie, PRB) in an OFDMA system or a symbol in an OFDM system.

In Embodiment 7 of the present invention, the adding module specifically includes:

Placement module for placing an S symbol at the head of the Ethernet frame;

The filling module is used to fill the idle bits into the physical resource block when there is no subsequent Ethernet frame; that is, place a T symbol at the end of the last Ethernet frame first, and use the T symbol to indicate that the follow-up is idle filling.

In Embodiment 7 of the present invention, the adaptation module is specifically configured to, within the agreed time period, the first physical resource block allocated to the user is the starting position of the FEC codeword to carry data, if the last physical resource block allocated to the user If the remaining part of the physical resource block is not enough to carry an FEC codeword, the remaining part is filled with invalid data or the FEC codeword is shortened according to the length of the remaining part, wherein the FEC codeword adopts a fixed length.

In the above-mentioned device embodiments, the included units are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be realized; in addition, the specific names of each functional unit are only for mutual convenience. The distinction is not intended to limit the protection scope of the present invention.

Those skilled in the art can understand that in the method provided by the embodiment of the present invention, all or part of the steps can be completed by program instructions and related hardware. For example, it can be done by running a program on a computer. The program can be stored in a readable storage medium, such as random access memory, magnetic disk, optical disk, etc.

Claims (20)

1. A method for adapting FEC codewords to physical resource blocks in a forward error correction mode, characterized in that the method comprises: Within the agreed time period, the first physical resource block allocated to the user is the starting position of the FEC codeword and starts to carry data. After carrying the FEC code word, the remaining part of the last physical resource block is not enough to carry an FEC code word, then the remaining part of the last physical resource block is filled with invalid data or according to the last physical resource block For the length of the remaining part, shorten the FEC codeword as the FEC codeword, and use a fixed length for the FEC codeword before the shortening. 2. The method according to claim 1, wherein the physical resource block is a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiple Access (OFDMA) system or a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiplexing (OFDM) system. Symbol symbol. 3. The method according to claim 1 or 2, wherein the agreed time period is a mapping MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system. 4. A method for adapting FEC codewords to physical resource blocks in a forward error correction mode, characterized in that the method comprises: In the agreed time period, according to the mapping MAP management message in the current period, indicate the processing mode of the first physical resource block allocated to the user or the processing mode of the last physical resource block allocated to the user in the current period. 5. The method according to claim 4, wherein the physical resource block is a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiple Access (OFDMA) system or a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiplexing (OFDM) system. Symbol symbol. 6. The method according to claim 4 or 5, wherein the processing method of indicating the first physical resource block allocated to the user in the current period comprises: indicating whether the first physical resource block resets the FEC Codeword boundary, if the FEC boundary is reset, the FEC codeword is aligned to the position of the first physical resource block, otherwise a fixed-length codeword is used, that is, a fixed-length codeword is carried at the end of the previous cycle and in front of the current cycle Codeword. 7. The method according to claim 4 or 5, wherein the processing method of indicating the last physical resource block allocated to the user in the current period is specifically: indicating that the remaining part of the last physical resource block is not enough to carry A processing method for a fixed-length FEC codeword, the processing method includes: filling the remaining part with invalid data, using a shortened FEC codeword for the FEC codeword according to the length of the remaining part, or the previous physical resource block of the current cycle Carries a fixed-length codeword together with the end of the previous period, and the remaining part is the remaining part of the physical resource block after the last physical resource block carries the FEC codeword carried by the previous physical resource block. resource blocks. 8. The method according to claim 4 or 5, wherein the agreed time period is a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system. 9. A forward error correction mode FEC code word synchronization method, is characterized in that, said method comprises: Receive physical frame; Detecting the physical frame to obtain frame synchronization; Analyzing the broadcast mapping MAP message to determine the physical resource block allocated to each user; According to the agreed rules, determine the way of delimiting codewords; Extract the FEC code word according to the fixed code length from the allocated physical resource block, and perform corresponding processing on the remaining part of the last physical resource block in the agreed time period according to the agreed rules, and the remaining part is the last physical resource The remaining part of the physical resource block after the block carries the FEC codeword carried by the immediately preceding physical resource block. 10. The method according to claim 9, wherein the physical resource block is a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiple Access (OFDMA) system or a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiplexing (OFDM) system. Symbol symbol. 11. The method according to claim 9 or 10, wherein the method of determining the codeword delimitation according to the agreed rules is specifically: Within the agreed time period, the first physical resource block of the user is the starting position of the FEC code word. 12. The method according to claim 11, wherein the agreed time period is a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system. 13. The method according to claim 9 or 10, wherein the corresponding processing of the remaining part of the last physical resource block in the agreed time period according to the agreed rules is specifically: If the agreed rule is that the remaining part of the last physical resource block of the agreed time period is filled with invalid data, discard the data carried by the remaining part of the last physical resource block, and the remaining part is the last physical resource The remaining part of the physical resource block after the block bears the FEC codeword carried by the immediately preceding physical resource block; If the agreed rule is that the remaining part of the last physical resource block of the agreed time period adopts the shortened code method, then extract the codeword of the length of the remaining part of the last physical resource block, and the remaining part is the last physical resource The remaining part of the physical resource block after the block carries the FEC codeword carried by the immediately preceding physical resource block. 14. The method according to claim 9 or 10, wherein the method of determining the codeword delimitation according to the agreed rules is specifically: indicating whether to reset the codeword boundary of the FEC in the current cycle through a MAP management message; The specific processing of the remaining part of the last physical resource block in the agreed time period according to the agreed rules is as follows: If the MAP management message indicates that the user does not reset the codeword boundary of FEC in the current period, the FEC codeword is carried across the physical resource blocks of two periods, and for the remaining part of the last physical resource block of the previous agreed time period and the following The first physical resource block of an agreed time period continues to extract the FEC codeword according to the fixed code length, and the remaining part is the FEC carried by the last physical resource block after the last physical resource block bears the weight of the previous physical resource block. Part of the remaining physical resource blocks after the codeword. 15. A forward error correction mode FEC codeword synchronization system, characterized in that the system comprises: A receiving module, configured to receive a physical frame; A detection module, configured to detect the physical frame received by the receiving module to obtain frame synchronization; The parsing module is used to parse the broadcast mapping MAP message, and determine the physical resource block allocated to each user; A determination module, configured to determine the codeword delimitation method according to the agreed rules; and The extraction module is used to extract the FEC code word according to the fixed code length from the allocated physical resource block, and perform corresponding processing on the remaining part of the last physical resource block in the agreed time period according to the agreed rules, and the remaining part is the Describe the remaining part of the physical resource blocks after the last physical resource block bears the FEC codeword carried by the immediately preceding physical resource block. 16. The system according to claim 15, wherein the physical resource block is a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiple Access (OFDMA) system or a two-dimensional time-frequency resource block in an Orthogonal Frequency Division Multiplexing (OFDM) system. Symbol symbol. 17. The system according to claim 15 or 16, wherein the method of determining the codeword delimitation according to the agreed rules is specifically: within the agreed time period, the first physical resource block of the user is an FEC The starting position of the codeword. 18. The system according to claim 17, wherein the agreed time period is a MAP indication period, a scheduling period for physical resource allocation, or a time period agreed by the system. 19. The system according to claim 15 or 16, wherein the corresponding processing of the remaining part of the last physical resource block in the agreed time period according to the agreed rules is specifically: If the agreed rule is that the remaining part of the last physical resource block of the agreed time period is filled with invalid data, discard the data carried by the remaining part of the last physical resource block, and the remaining part is the last physical resource The remaining part of the physical resource block after the block bears the FEC codeword carried by the immediately preceding physical resource block; If the agreed rule is that the remaining part of the last physical resource block of the agreed time period adopts the shortened code method, then extract the codeword of the length of the remaining part of the last physical resource block, and the remaining part is the last physical resource The remaining part of the physical resource block after the block carries the FEC codeword carried by the immediately preceding physical resource block. 20. The system according to claim 15 or 16, wherein the determining module is specifically configured to indicate whether to reset the codeword boundary of the FEC in the current cycle through a MAP management message; The extraction module performs corresponding processing on the remaining part of the last physical resource block in the agreed time period according to the agreed rules, specifically: If the MAP management message indicates that the user does not reset the codeword boundary of FEC in the current period, the FEC codeword is carried across the physical resource blocks of two periods, and for the remaining part of the last physical resource block of the previous agreed time period and the following The first physical resource block of an agreed time period continues to extract the FEC codeword according to the fixed code length, and the remaining part is the FEC carried by the last physical resource block after the last physical resource block bears the weight of the previous physical resource block. Part of the remaining physical resource blocks after the codeword.