Coding apparatus, coding method, data communication apparatus, and data communication method

Abstract

A 4B5B encoder converts an inputted 4-bit data into a pattern of a 5-bit data in which (i) the number of bits of consecutive “0” data values is permitted to be maximum two, and, simultaneously, (ii) maximum one bit of head end two bits is permitted to have a “0” data value and maximum one bit of tail end two bits is permitted to have a “0” data value. A 5N-bit command encoder converts a command into a command pattern in which the number of bits contained in consecutive “0” data values is permitted to be maximum two. The data after the conversion and the command after the conversion are converted into NRZI codes by an NRZI encoder.

1 - 12 . (canceled) 
     
     
         13 . A data communication method for assigning a frame with an identifier to identify the frame and transmitting the frame to a communication path,
 the method comprising:   assigning a data frame, which has a highest communication frequency in a communication network, with an identifier that has a shortest identifier length, and transmitting the data frame with the identifier to the communication path; and   assigning an arbitrary frame other than the data frame having the highest communication frequency with an identifier which has an arbitrary identifier length and transmitting the arbitrary frame to the communication path.   
     
     
         14 . The data communication method according to  claim 13 , wherein:
 Na is defined as a node number of nodes connected to the communication path;   Nb is defined as an address space required for the nodes;   N, N1, N2 are coefficients;   N1 is obtained to satisfy Na≦2N1;   N2 is obtained to satisfy Nb=2N2;   N is obtained to be N1+N2; and   a data frame having an ID length of N bits is determined to be a data frame that has a highest communication frequency.   
     
     
         15 . The data communication method according to  claim 13 , wherein:
 an ACK (acknowledgement) frame is assigned with an identifier which has a second shortest identifier length and transmitted to the communication path.   
     
     
         16 . The data communication method according to  claim 15 , wherein:
 a command frame is assigned with an identifier which has a third shortest identifier length and transmitted to the communication path.   
     
     
         17 . The data communication method according to  claim 16 , wherein:
 K expansion use data frames (k is a natural number) are assigned, in an order from a shortest frame length, with identifiers having 4th to {4+(k−1)}th shortest identifier lengths and transmitted to the communication path.   
     
     
         18 . The data communication method according to  claim 13 , wherein: a command frame is assigned with an identifier which has a second shortest identifier length and transmitted to the communication path. 
     
     
         19 . The data communication method according to  claim 18 , wherein:
 K expansion use data frames (k is a natural number) are assigned, in an order from a shortest frame length, with identifiers having 3rd to {3+(k−1)}th shortest identifier lengths and transmitted to the communication path.   
     
     
         20 . The data communication method according to  claim 13 , wherein:
 an identifier length of the identifier is determined such that a sum of the identifier length of the identifier, a remote length of a remote that indicates write or read of data, a size length of a size that indicates a length of data, and an ID length of an ID that indicates an address space to access contains bits of a multiple of 8.   
     
     
         21 . A data communication apparatus comprising:
 an identifier assignment device to assign a frame communicated in a communication network with an identifier that identifies the frame; and   a transmission device to transmit the frame assigned with the identifier to a communication path,   wherein:   the identifier assignment device assigns a data frame, which has a highest communication frequency in the communication network, with an identifier that has a shortest identifier length, and assigns a frame other than the data frame having the highest communication frequency with an identifier which has an arbitrary identifier length.   
     
     
         22 . The data communication apparatus according to  claim 21 , wherein:
 the identifier assignment device assigns an ACK (Acknowledgement) frame with an identifier which has a second shortest identifier length.   
     
     
         23 . The data communication apparatus according to  claim 22 , wherein:
 the identifier assignment device assigns a command frame with an identifier which has a third shortest identifier length.   
     
     
         24 . The data communication apparatus according to  claim 23 , wherein:
 the identifier assignment device assigns K expansion use data frames (k is a natural number), in an order from a shortest frame length, with identifiers having 4th to {4+(k−1)} th shortest identifier lengths.   
     
     
         25 . The data communication apparatus according to  claim 21 , wherein:
 the identifier assignment device assigns a command frame with an identifier which has a second shortest identifier length.   
     
     
         26 . The data communication apparatus according to  claim 25 , wherein:
 the identifier assignment device assigns K expansion use data frames (k is a natural number) in an order from a shortest frame length, with identifiers having 4th to {4+(k−1)} th shortest identifier lengths.   
     
     
         27 . The data communication apparatus according to  claim 21 , wherein:
 the identifier assignment device determines an identifier length of the identifier such that a sum of the identifier length of the identifier, a remote length of a remote that indicates write or read of data, a size length of a size that indicates a length of data, and an ID length of an ID that indicates an address space to access contains bits of a multiple of 8.   
     
     
         28 . A data communication method comprising:
 performing 4B5B coding of a link layer frame containing data;   adding a preamble, a frame start portion, and a frame end portion to the link layer frame having undergone the 4B5B coding, generating a physical layer frame;   performing an NRZI (Non Return to Zero Inversion) coding of the generated physical layer frame;   performing, before transmitting the physical layer frame having undergone the NRZI coding as a transmission frame to the communication path, a bit error detection which determines whether a transmission data in the transmission frame is normal;   performing, when receiving a physical layer frame as a reception frame from the communication path, a coding error detection that determines whether the 4B5B coding of the received physical layer frame is normal;   performing a CRC (Cyclic Redundancy Check) error detection which determines whether data in a link layer frame included in the received physical layer frame is normal;   performing a form error detection which determines whether a configuration and a content of the link layer frame are normal;   performing a state error detection which determines whether an order of a bit string of the link layer frame is normal; and   performing a timeout error detection which determines whether an ACK (Acknowledgement) frame is normally received within a predetermined time.   
     
     
         29 . A data communication apparatus that (i) performs 4B5B coding of a link layer frame containing data, (ii) adds a preamble, a frame start portion, and a frame end portion to the link layer frame having undergone the 4B5B coding, generating a physical layer frame, (iii) performs an NRZI (Non Return to Zero Inversion) coding of the generated physical layer frame, and (iv) transmits the physical layer frame having undergone the NRZI coding as a transmission frame to a communication path,
 the data communication apparatus comprising:   a bit error detection device that performs a bit error detection which determines whether a transmission data contained in the transmission frame is normal;   a coding error detection device that performs, when receiving a physical layer frame as a reception frame from the communication path, a coding error detection that determines whether a 4B5B coding of the physical layer frame is normal;   a CRC error detection device that performs a CRC (Cyclic Redundancy Check) error detection which determines whether data contained in a link layer frame contained in the physical layer frame is normal;   a form error detection device that performs a form error detection which determines whether a configuration and a content of the link layer frame are normal;   a state error detection device that performs a state error detection which determines whether an order of a bit string in the link layer frame is normal; and   a timeout error detection device that performs a timeout error detection which determines whether an ACK (acknowledgement) frame is normally received within a predetermined time.   
     
     
         30 . A data communication method for communicating a communication frame between a transmission side and a reception side, the communication frame containing (i) a control information portion that contains a control code, (ii) a data portion that contains a transmission data, and (iii) an error detection portion that contains an error detection code, the data communication method comprising:
 transmitting, by the transmission side, the error detection portion that contains a control-use error detection code that is used for detecting an error in the control information portion; and   performing, by the reception side, an error detection of the control information portion based on the control-use error detection code.   
     
     
         31 . The data communication method according to  claim 30 , further comprising:
 dividing, by the transmission side, the data portion into a plurality of unit data portions, each of which includes a predetermined number of bits, and providing, by the transmission side, a plurality of error detection portions, which execute error detections, so as to correspond to the unit data portions, respectively; and   performing, by the reception side, an error detection for each of the unit data portions.   
     
     
         32 . The data communication method according to  claim 31 , wherein:
 the transmission side generates the control-use error detection code in the error detection portion so as to perform an error detection of both of the control information portion and a following first unit data portion collectively.   
     
     
         33 . The data communication method according to  claim 31 , wherein:
 the control-use error detection code and an error detection code added to each of the unit data portions use a same kind of an error detection code.   
     
     
         34 . The data communication method according to  claim 31 , wherein:
 the reception side issues a request to the transmission side to re-transmit an error-occurred portion where an error was detected by the error detection code; and   the transmission side re-transmits only the error-occurred portion upon receiving the request to re-transmit.   
     
     
         35 . The data communication method according to  claim 34 , wherein:
 the reception side issues a request to the transmission side to change a bit number of the error detection code depending on a frequency of the request to re-transmit; and   the transmission side changes the bit number of the error detection code according to the request to change the bit number.   
     
     
         36 . The data communication method according to  claim 30 , wherein:
 the transmission side
 applies a 4B5B coding to the communication frame serving as a link layer frame, 
 adds a preamble, a frame start portion, and a frame end portion to the link layer frame having undergone the 4B5B coding, generating a physical layer frame, 
 applies an NRZI (Non Return to Zero Inversion) coding to the generated physical layer frame, 
 performs, when transmitting the physical layer frame having undergone the NRZI coding as a transmission frame to the communication path, a bit error detection which determines whether a transmission data in the transmission frame is normal, and 
 performs a form error detection which determines whether a configuration and a content of the link layer frame are normal; and 
   the reception side
 performs a coding error detection that determines whether the 4B5B coding of the received physical layer frame is normal, 
 performs an error detection which determines whether the control information portion and the data portion contained in the link layer frame are normal using the error detection code, 
 performs a form error detection which determines whether a configuration and a content of the link layer frame are normal, 
 performs a state error detection which determines whether an order of a bit string of the link layer frame is normal, and 
 performs a timeout error detection which determines whether an ACK (Acknowledgement) frame is normally received within a predetermined time. 
   
     
     
         37 . A data communication apparatus comprising a transmitter and a receiver, the receiver transmitting a communication frame that contains (i) a control information portion that contains a control code, (ii) a data portion that contains a transmission data, and (iii) an error detection portion that contains an error detection code,
 the receiver receiving the communication frame and performing an error detection in the communication frame using the error detection code,   wherein:   the transmitter includes a control-use error detection code generation device to generate a control-use error detection code to perform an error detection of the control information portion;   the transmitter transmits the communication frame such that the error detection portion contains the control-use error detection code; and   the receiver performs an error detection of the control information portion based on the control-use error detection code upon receiving the communication frame.   
     
     
         38 . The data communication apparatus according to  claim 37 , wherein:
 the transmitter divides the data portion into a plurality of unit data portions, each of which includes a predetermined number of bits;   the transmitter provides a plurality of error detection portions, which execute error detections, so as to correspond to the unit data portions, respectively; and   the receiver performs an error detection for each of the unit data portions.   
     
     
         39 . The data communication apparatus according to  claim 38 , wherein:
 the control-use error detection code generation device generates the control-use error detection code in the error detection portion so as to perform an error detection of both of the control information portion and a following first unit data portion collectively.   
     
     
         40 . The data communication apparatus according to  claim 38 , wherein:
 the control-use error detection code and an error detection code added to each of the unit data portions use a same kind of an error detection code.   
     
     
         41 . The data communication apparatus according to  claim 38 , wherein:
 the receiver issues a request to the transmitter to re-transmit an error-occurred portion where an error was detected by the error detection code; and   the transmitter re-transmits only the error-occurred portion upon receiving the request to re-transmit.   
     
     
         42 . The data communication apparatus according to  claim 41 , wherein:
 the receiver issues a request to the transmitter to change a bit number of the error detection code depending on a frequency of the request to re-transmit; and   the transmitter changes the bit number of the error detection code according to the request to change the bit number.   
     
     
         43 . The data communication apparatus according to  claim 37 , wherein:
 the transmitter
 applies a 4B5B coding to the communication frame serving as a link layer frame, 
 adds a preamble, a frame start portion, and a frame end portion to the link layer frame having undergone the 4B5B coding, generating a physical layer frame, 
 applies an NRZI (Non Return to Zero Inversion) coding to the generated physical layer frame, and 
 transmits the physical layer frame having undergone the NRZI coding as a transmission frame to a communication path; 
   the transmitter includes
 a bit error detection device to perform a bit error detection which determines whether a transmission data in the transmission frame is normal; 
 a form error detection device that performs a form error detection which determines whether a configuration and a content of the link layer frame are normal; and 
 a timeout error detection device to perform a timeout error detection which determines whether an ACK (Acknowledgement) frame is normally received within a predetermined time, 
   the receiver includes
 a coding error detection device that performs a coding error detection that determines whether a 4B5B coding of a physical layer frame is normal when receiving the physical layer frame as a reception frame from the communication path; 
 a coding error detection device to perform an error detection which determines whether the control information portion and the data portion contained in the link layer frame are normal using the error detection code; 
 a form error detection device that performs a form error detection which determines whether a configuration and a content of the link layer frame are normal; and 
 a state error detection device that performs a state error detection which determines whether an order of a bit string of the link layer frame is normal.