JP2013017018A - Decorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent increase of hardware and increase of the time required for processing.SOLUTION: The decoder 1 comprises a reception time management function unit 6 which manages the scheduled reception start time of a signal received from each transmission side device, based on the transmission start time information and the length information of transmission time being notified to each transmission side device, a decoding system determination function unit 7 which determines a decoding system from the identification information of a transmission side device of a signal received at the scheduled reception start time, and a decoding function unit 8 which decodes a signal on the basis of the decoding system information. The reception time management function unit 6 completes the preparation of decoding of the decoding function unit 8 before the scheduled processing start time, by outputting the identification information of a transmission side device of a signal received at the scheduled reception start time to the decoding system determination function unit 7 prior to the scheduled processing start time of the decoding function unit 8.

Description

  The present invention relates to a communication system such as a PON system, and in particular, a receiving side apparatus decodes in accordance with a coding method of a signal transmitted by a plurality of transmitting side apparatuses in time division in accordance with transmission timing notified by a receiving side apparatus. The present invention relates to a decoding processing apparatus that performs signal decoding processing by dynamically switching a method.

  Conventionally, the reception side device determines the reception time of the signal according to the transmission / reception procedure in which the transmission side device transmits a signal in accordance with the transmission start time information calculated by the reception side device and notified to the transmission side device and the transmission time length information. A communication form to be managed is known. A PON (Passive Optical Network) system is an example of a network having such a communication form (see Non-Patent Document 1 and Non-Patent Document 2).

  An intra-terminal device (Optical Line Terminal: OLT) that terminates the access network accommodates a plurality of subscriber-side devices (Optical Network Unit: ONU), manages the reception time from each ONU, and is determined by the type of ONU Decrypt the received frame encrypted by. In the PON system, transmission start time information and transmission time length information (hereinafter referred to as grant information) calculated by the OLT are stored in a gate frame and transmitted to each ONU to notify the transmission timing.

  In such a PON system, a received frame is encrypted with a plurality of different encryption methods (for example, the encryption method (I) disclosed in Non-Patent Document 3 and the encryption method (II) disclosed in Non-Patent Document 4). When accommodating ONUs simultaneously, it is necessary to dynamically switch between the decryption function of the encryption method (I) and the decryption function of the encryption method (II) for each frame reception (burst reception).

  In order to match the decryption method with the encryption method, a method of extracting information for determining the encryption method from a portion that is not encrypted in the received frame, for example, a specific portion of the preamble, can be considered. Specifically, for example, the ONU writes a code for determining the encryption method at a specific bit position of the preamble of the transmission frame and transmits the code, and the OLT extracts the code from the received frame and determines the encryption method. There is a way. As another method, the OLT extracts the logical link ID (LLID) described in the preamble of the received frame, and the type information of the ONU to which the LLID is assigned is registered from the ONU registration information held by the OLT. There is a method of determining an encryption method by searching.

  FIG. 8 shows a configuration of a conventional decoding processing apparatus generally assumed from an extraction method for extracting identification information for determining a decoding method from a received frame. The decoding processing apparatus 100 searches the ONU type information corresponding to the identification information extraction function unit 101 for extracting the logical link ID from the specific location of the preamble of the received frame and the registration information of the ONU corresponding to the logical link ID. A decoding method determination function unit 102 that determines the encryption method used at the time of encoding, a frame holding function unit 103 that holds a received frame until the decoding method switching unit 104 described later completes switching of the decoding method, and a decoding method And a decoding processing function unit 104 that decodes the received frame in accordance with the decoding method determined by the determination function unit 102.

IEEE Standards 802.3ah, “Ethernet in the First Mile”, 2004 IEEE Standards 802.3av, “10Gb / s Ethernet Passive Optical Network”, 2009 IEEE Standards 802.1AE, “Media Access Control (MAC) Security”, 2006 NIST 800-38A (AES-CTR), “Advanced Encryption Standard (AES)”, 2001

  In the conventional decoding processing apparatus shown in FIG. 8, as shown in FIG. 9, the determination of the decoding method, the switching of the operation of the decoding processing function unit 104 to the decoding method, the setting of necessary parameters, etc. Was received after reading the identification information of the ONU and arrived at the decoding processing device 100, so that the received frame was waited until the decoding processing function unit 104 completed the switching of the decoding method and the decoding process could be started. It was necessary to let Therefore, it is necessary to add the frame holding function unit 103 that holds the received frame, and there is a problem that hardware increases.

  In addition, the conventional decoding processing apparatus has a problem that the time required to complete the decoding process after receiving a signal is increased by waiting for the frame. In the example of FIG. 9, the received frame is stored in the frame holding function unit 103 after the delay time Tdint required for the identification information extraction function unit 101 to extract the identification information from the received frame, and the decoding method determination function unit 102 further receives the decoding method. After the delay time Tdc required for the decoding processing function unit 104 to switch the decoding method, the decoding processing function unit 104 starts decoding processing, and after the delay time Tddec required for this decoding processing, the decoded frame is output. The

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a decoding processing apparatus capable of preventing an increase in hardware and an increase in processing time.

  The present invention relates to a plurality of encoding methods, and in a decoding processing device that decodes a received signal whose reception start scheduled time and encoding method are known, transmission start time information and transmission time to be notified to each transmitting side device Based on the length information, the reception time management means for managing the scheduled reception start time of the signal received from each transmission side device, and the decoding method from the identification information of the transmission side device of the signal received at the scheduled reception start time A decoding method determining means for determining, and a decoding processing means for decoding a signal received at the scheduled reception start time based on the decoding method information output from the decoding method determining means, and the reception time managing means The decoding method prior to the scheduled processing start time of the decoding processing means is determined based on the scheduled reception start time, and the identification information of the transmission side device of the signal received at the scheduled reception start time By outputting the determination means, characterized in that to complete the preparation of the decoding process of the decoding processing unit to the processing scheduled start time earlier.

In the configuration example of the decoding processing device according to the present invention, the reception time management unit determines the decoding method after the decoding method determination unit receives the identification information of the transmission side device, and the decoding processing unit uses the decoding method. Receiving the information and outputting the identification information of the transmission side device to the decoding method determining means by going back from the scheduled processing start time for a time longer than the time required to complete the preparation for the decoding process. Is.
Further, in one configuration example of the decoding processing apparatus of the present invention, the decoding processing means has a plurality of decoding processing function means for each decoding processing step obtained by dividing the decoding processing, and each decoding processing function means is determined in advance. The signal processing is executed in the given order, and the processed signal is output to the next decoding processing function means.
Further, in one configuration example of the decoding processing apparatus of the present invention, each decoding processing function means transmits the decoding method information output from the decoding method determining means in the same order as the order in which signal processing is performed. The decoding method is set in the order of information transmission.

Further, in one configuration example of the decoding processing apparatus of the present invention, each decoding processing function means includes holding means for holding the transmitted decoding method information.
Further, in one configuration example of the decoding processing device of the present invention, the decoding processing means does not perform decoding processing of the signal when the signal received from the transmitting side device is not encoded. is there.
Moreover, in one configuration example of the decryption processing apparatus of the present invention, the decryption process is a decryption process of an encrypted signal.
In addition, one configuration example of the decoding processing apparatus according to the present invention is characterized in that decoding processing of an EPON received frame is performed.

  According to the present invention, the identification information of the transmission-side device of the signal received at the scheduled reception start time is output to the decoding method determination unit prior to the scheduled processing start time of the decoding processing unit, so that the processing start time is before the scheduled processing start time. Since it is possible to complete the preparation of the decoding process of the decoding processing means, the decoding process can be started without waiting for the received signal from the transmission side device, so the time required for completing the decoding process after receiving the signal The decoding method can be switched without increasing the value. In the present invention, since it is not necessary to add a frame buffer, the decoding method can be switched without increasing hardware.

  In the present invention, the decoding processing means is composed of a plurality of decoding processing function means for each decoding processing step obtained by dividing the decoding processing, so that the signal reception is completed and the next signal reception is started. Since the shortest interval can be shortened to the maximum value of the sum of the time required for setting the decoding method and the time required for the decoding process in units of decoding processing function means, the throughput of the decoding process can be increased. There is. In the present invention, the configuration of the decoding processing means can be determined as appropriate without increasing the time calculation load, and the maximum sum of the time required for setting the decoding method and the time required for the decoding processing can be maximized. By reducing the value, the reception interval between signals can be shortened, and the throughput of decoding processing is increased. Further, in the present invention, the decoding method determination means holds the decoding processing method information during the effective period, so that each decoding processing function means does not need to hold the decoding method information, and the decoding processing method information is not changed. Since it only needs to be reflected in the setting, the configuration of each decoding processing function means can be simplified.

  In the present invention, each decoding processing function means is provided with a holding means for holding the decoding method information, so that the decoding method information output from the decoding method determining means and transmitted to the decoding processing means is shortened to 1 bit width. Can do. Therefore, in the present invention, the time other than the transmission of the decoding scheme information can be utilized for the transmission of other signals using the wiring for transmitting the decoding scheme information.

It is a block diagram which shows the structure of the decoding processing apparatus which concerns on the 1st Embodiment of this invention. It is a definition explanatory drawing of the time information which a reception time management function part uses for time calculation in the 1st embodiment of the present invention. It is a timing chart which shows the operation | movement of the time which a reception time management function part calculates in the 1st Embodiment of this invention, a decoding system determination function part, and a decoding process function part. It is a block diagram which shows the structure of the decoding processing apparatus which concerns on the 2nd Embodiment of this invention. It is a timing chart which shows operation | movement of the decoding process function part which concerns on the 2nd Embodiment of this invention. It is a timing chart which shows operation | movement of the decoding process function part which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the decoding processing apparatus which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the structure of the conventional decoding processing apparatus. It is a figure which shows the example of operation | movement timing of the conventional decoding processing apparatus.

[Principle of the Invention]
In the present invention, using the fact that the frame reception (burst reception) scheduled time is known to the OLT, the switching and setting of the decoding method is started prior to the frame input, and the preparation for performing the decoding process is completed in advance. The configuration is disclosed. That is, based on the transmission start time information and the transmission time length information (grant information) that the OLT calculates and notifies the ONU as the transmission timing of the upstream burst signal, the reception start time of the burst signal from each ONU is calculated, The transmission source ONU starts switching and setting to the decryption method suitable for the encryption method used for encryption prior to the scheduled reception start time, and switching the decryption method until the frame is input to the decryption processing function unit. Complete the configuration.

  The scheduled reception start time is already determined together with the scheduled reception completion time of the burst signal received immediately before the OLT calculates the grant information to the ONU. Therefore, the laser off time and laser on time between burst receptions are determined. A state in which the received frame decoding process can be started by switching the algorithm using the period in which the frame including the time and the synchronization pull-in time is not received, and the period required for the internal processing performed prior to the decoding process such as error correction processing. Prepare in advance.

  As a result, in the present invention, since the decoding process can be started without waiting for the received frame, the decoding method can be performed without increasing the time required from the reception of the signal from the transmission side device to the completion of the decoding process. Can be switched. Further, since it is not necessary to add a frame holding circuit, the decoding method can be switched without increasing hardware.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a decoding processing apparatus according to the first embodiment of the present invention.
The decoding processing apparatus 1 is provided in the OLT of the PON system, and includes an input terminal 2 that receives a frame from each ONU, an output terminal 3 that outputs a frame, a scheduled reception start time calculation unit 4, and a reception time management. A function unit 6, a decoding method determination function unit 7, and a decoding processing function unit 8 are included.

  The scheduled reception start time calculation unit 4 calculates the scheduled reception start time of the burst signal from each ONU for each ONU based on the transmission start time information notified to each ONU and the transmission time length information (grant information). If the transmission start time of the ONU and the length of the transmission time are known, it is possible to calculate the scheduled reception start time from the known transmission delay time between the ONU and the OLT. The scheduled reception start time calculation unit 4 sets the length of the ONU transmission time as the reception time width. A technique for calculating the ONU transmission start time and the length of the transmission time, and means for notifying each ONU of the transmission start time information and the transmission time length information (grant information) are well-known techniques in the PON system. Since there is, explanation is omitted.

  The OLT has identification information management means (not shown) that stores identification information of each ONU. The identification information of the transmission source ONU of the burst signal received at the scheduled reception start time is obtained from this identification information management means. It is possible to obtain.

The reception time management function unit 6 includes a terminal 60 that receives time information (PON clock) managed by the OLT, a terminal 61 that receives scheduled reception start time information of a burst signal from the reception start scheduled time calculation unit 4, and a scheduled reception start time. A terminal 62 for receiving reception time width information of a burst signal from the calculation unit 4, a terminal 63 for receiving ONU identification information, a terminal 64 for sending a signal (reception slot signal) indicating a reception time zone of a frame, a reception slot signal, And a terminal 65 for sending ONU identification information at the same time.
The reception time management function unit 6 notifies the decoding method determination function unit 7 of the identification information of the transmission source ONU at the timing when the determination output of the decoding method is in time for the time zone in which the frame is to be received from the ONU.

The decoding method determination function unit 7 includes a terminal 70 that receives a reception slot signal from the reception time management function unit 6, a terminal 71 that receives ONU identification information from the reception time management function unit 6, and a terminal 72 that transmits decoding method information. Have.
The decoding method determination function unit 7 holds a table (not shown) in which the correspondence between the ONU identification information and the decoding method is registered, and refers to this table to determine the ONU received from the reception time management function unit 6. A decoding method corresponding to the identification information is determined, and decoding method information for designating the decoding method is notified to the decoding processing function unit 8.

  The decoding processing function unit 8 includes a terminal 80 that receives an input frame, a terminal 81 that receives decoding method information from the decoding method determination function unit 7, and a terminal 82 that outputs a frame. When the received frame is encoded, the decoding processing function unit 8 decodes the frame using the designated decoding method and outputs the frame.

  Hereinafter, the operation of the present embodiment will be described with reference to FIGS. FIG. 2 is an explanatory diagram of the definition of time information used by the reception time management function unit 6 for time calculation. FIG. 3 shows the time calculated by the reception time management function unit 6 and the operations of the decoding method determination function unit 7 and the decoding processing function unit 8. It is a timing chart which shows.

  The reception time management function unit 6 acquires the scheduled reception start time information of the burst signal and the reception time width information of the burst signal from the scheduled reception start time calculation unit 4, and also transmits the burst signal from the identification information management unit (not shown) of the OLT. Acquire identification information of the transmission source ONU. In the present embodiment, the identification information of the transmission source ONU is set to internal ID = i, the scheduled reception start time for receiving a burst signal from ONU (i) to which the internal ID = i is assigned is Treceive_ (i), and burst The signal reception time width is assumed to be Tlength_ (i).

A known burst overhead time Tboh from the beginning of the burst signal to the beginning of the frame in the burst signal, a known in-device delay time Tdint from when the frame arrives at the decoding processing device 1 until it is input to the decoding processing function unit 8, If the burst signal reception start time Treceive_ (i) is used, the process start time Tr0 (i) of the received frame received from the ONU (i) is expressed by the following equation.
Tr0 (i) = Treceive_ (i) + Tboh + Tdint (1)

Tjd is a known time required from the reception of the reception slot signal (here, logic level H) in the decoding method determination function unit 7 until the decoding method function unit 8 designates the decoding method. Assuming that the known time required from the reception of the decoding method information from the method determination function unit 7 to the completion of switching and setting for the decoding process and the start of the decoding process is Tsu, the reception time management function unit 6 The time Tr1 (i) at which the reception slot signal corresponding to the reception frame received from the transmission source ONU (i) should be set to the logic level H is calculated as shown in the following equation.
Tr1 (i) = Tr0 (i) -Tsu-Tjd
= {Treceive_ (i) + Tboh + Tdint} -Tsu-Tjd
... (2)

Furthermore, when the known required time Tddec required for the decoding process in the decoding processing function unit 8 and the reception time width Tlength_ (i) of the burst signal are used, the expected decoding process completion time Te0 () of the received frame received from the ONU (i) i) can be expressed as:
Te0 (i) = Treceive_ (i) + Tboh + Tdint
+ Tlength_ (i) + Tddec (3)

The reception time management function unit 6 receives the scheduled decoding process completion time Te0 (i) and the time Tjd required from the reception of the reception slot signal in the decoding method determination function unit 7 until the decoding processing function unit 8 designates the decoding method. Are used to calculate the time Te1 (i) at which the received slot signal should be at the logic level L as shown in the following equation.
Te1 (i) = Te0 (i) -Tjd
= {Treceive_ (i) + Tboh + Tdint + Tlength_ (i)
+ Tddec} -Tjd (4)

  As shown in FIG. 3, when the time indicated by the PON clock is Tr1 (i), the reception time management function unit 6 sets the reception slot signal to a value indicating reception (logic level H) and at the same time the transmission source ONU (i ) Identification information (internal ID = i) is output. The reception time management function unit 6 sets the reception slot signal to a value (logic level L) indicating non-reception when the time indicated by the PON clock is Te1 (i).

  The reception slot signal output from the reception time management function unit 6 indicates that the ONU identification information is valid when the logic level is H, and the ONU identification information is invalid when the logic level is L. Signal. As described above, the reception slot signal transits from the logic level L to the logic level H at time Tr1 (i), and transits from the logic level H to the logic level L at time Te1 (i). The transition from the logic level L to the logic level H gives an opportunity for the decoding method determination function unit 7 to operate based on the ONU identification information output from the reception time management function unit 6.

The decoding method determination function unit 7 receives the ONU identification information from the reception time management function unit 6 and designates the decoding method corresponding to the identification information. Since the decoding method determination function unit 7 receives the reception slot signal (logic level H) and the ONU identification information at time Tr1 (i), the time Tr2 (i) at which the decoding method determination function unit 7 outputs the decoding method information is After the required time Tjd for determination, the following equation is obtained.
Tr2 (i) = Tr1 (i) + Tjd = (Tr0 (i) -Tjd-Tsu) + Tjd
= Tr0 (i) -Tsu (5)

Based on the decoding method information output from the decoding method determination function unit 7, the decoding processing function unit 8 performs settings for decoding processing and switching operations, and starts preparations for decoding the received frame. As shown in FIG. 3, the time Tr3 (i) at which the decoding process can be started is only the time Tsu required for preparation from the time Tr2 (i) when the decoding processing function unit 8 receives the decoding method information from the decoding method determination function unit 7. Since it is later, the following equation is obtained.
Tr3 (i) = Tr2 (i) + Tsu = (Tr0 (i) -Tsu) + Tsu
= Tr0 (i) (6)

That is, the decoding processing function unit 8 completes the preparation by the frame input scheduled time Tr0 (i), and the decoding processing can be started.
The decoding method determination function unit 7 receives a reception slot signal (logic level L) from the reception time management function unit 6 at time Te1 (i). Accordingly, the time Te2 (i) at which the decoding method information output from the decoding method determination function unit 7 becomes invalid is after the required time Tjd necessary for determination from the time Te1 (i), and therefore, the following equation is obtained.
Te2 (i) = Te1 (i) + Tjd = (Te0 (i) -Tjd) + Tjd
= Te0 (i) (7)

  The setting of the decoding processing function unit 8 for decoding the received frame from the ONU (i) is completed by the preparation start time Tr0 (i) of the frame received from the ONU (i), and the decoding process is completed. It is valid until the scheduled time Te0 (i), and the setting role is finished at the time Te0 (i).

Next, the setting of the decoding processing function unit 8 for decoding the frame received from the ONU (i + 1) to which the internal ID = i + 1 is assigned is completed by the frame processing scheduled start time Tr0 (i + 1). There is a need to. The preparation start time Tr2 (i + 1) for that is given by the following equation.
Tr2 (i + 1) = Tr0 (i + 1) -Tsu
= Treceive_ (i + 1) + Tboh + Tdint-Tsu (8)

As described above, the decoding method corresponding to ONU (i) is effective until time Te0 (i), while the decoding method setting corresponding to ONU (i + 1) starts from time Tr2 (i + 1), so that time Te0 ( The condition for controlling so that i) and Tr2 (i + 1) do not overlap is as follows.
Tr2 (i + 1) ≧ Te0 (i) (9)

Substituting Equation (3) and Equation (8) into Equation (9) yields the following equation.
{Treceive_ (i + 1) + Tboh + Tdint-Tsu}
≧ {Treceive_ (i) + Tboh + Tdint + Tlength_ (i)
+ Tddec} (10)

Transposing equation (10) yields:
Treceive_ (i + 1)-{Treceive_ (i)
+ Tlength_ (i)} ≧ Tsu + Tddec (11)

  From the equation (11), the interval from the end of reception of the burst signal to the start of reception of the next burst signal is the sum of the required time Tsu required for setting the decoding method in the decoding processing function unit 8 and the required time Tddec required for the decoding process. As described above, it can be understood that the OLT may notify the ONU of the transmission start time of the burst signal.

  When a non-encoded frame is received from the ONU, the decoding processing function unit 8 outputs the frame without performing the decoding process regardless of the designation of the decoding method.

  FIG. 3 shows an example in which the setting of the decoding processing function unit 8 is completed by the frame input scheduled time Tr0. However, the setting completion of the decoding processing function unit 8 may not be just the frame input start time. The timing at which the reception time management function unit 6 outputs the reception slot signal may be appropriately set so that the setting is completed before the start time.

  According to the present embodiment, the time during which no frame is received between burst reception and the time from the start of reception until the frame is input to the decoding processing device (burst overhead and in-device delay time) are decoded. Buffering is unnecessary, that is, the frame holding function unit (frame buffer) as shown in FIG. 8 is not required, and the decoding method can be switched without increasing the processing time. It becomes possible.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 4 is a block diagram showing the configuration of the decoding processing apparatus according to the second embodiment of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals.

  The decoding processing device 1a of the present embodiment includes an input terminal 2, an output terminal 3, a scheduled reception start time calculation unit 4, a reception time management function unit 6a, a decoding method determination function unit 7a, and a decoding processing function unit. 8a.

The difference between the present embodiment and the first embodiment is that the decoding processing step of the decoding processing function unit 8a is divided.
Further, the difference between the present embodiment and the first embodiment is that the reception time management function unit 6a determines the decoding method information of the burst signal received from the ONU (i + 1) by the decoding processing function unit 8a as ONU (i + 1). The ONU identification information is sent to the decoding method determination function unit 7a so that it is received not at the scheduled reception start time of the burst signal from the previous ONU (i) but at the scheduled reception end time of the frame from the previous ONU (i).

  In the first embodiment, the reception slot signal transits from the logic level L to the logic level H at the frame reception scheduled start time Tr1, and transits from the logic level H to the logic level L at the scheduled decoding processing completion time Te1. The valid period of the ONU identification information starts when the reception slot signal transitions from the logic level L to the logic level H and extends from the logic level H to the logic level L.

  On the other hand, in the present embodiment, the reception slot signal does not change from the logical level L to the logical level H at the scheduled frame reception start time, but from the logical level H to the logical level L at the scheduled frame reception completion time. Transition to.

  Output of identification information of ONU (i + 1) starts when the reception slot signal corresponding to ONU (i) which is the previous transmission side device transits from the logic level H to the logic level L, and the time is valid As the start of the period, the period until the reception slot signal next transitions from the logic level H to the logic level L is defined as the valid period of the identification information of the ONU (i + 1). That is, while the reception slot signal is at the logical level L, the identification information of the transmission source ONU of the frame to be received next is output, and the period of the logical level L and the period of the next logical level H are valid for the identification information of the ONU. It becomes a period.

  Another difference from the first embodiment is that the decryption processing function unit 8a is decrypted in the order of decryption processing to be performed, the decryption processing function units 8a-1, 8a-2,..., 8a- (N-1). , 8a-N (N is an integer equal to or greater than 2) decoding processing function units, and transmits the decoding method information to the next decoding processing function unit in the same order as the decoding processing over the same time as the decoding processing. Thus, preparation for decoding is started in the order of transmission.

The decoding processing function unit 8a-1 first receives the decoding method information designated by the decoding method determination function unit 7a, and the decoding processing function unit 8a-1 has the same time as the time required for the decoding process from the time of receiving the decoding method information. After the elapse, the decoding method information is transmitted to the decoding processing function unit 8a-2.
After receiving the decoding method information, the decoding processing function unit 8a-1 has passed the same time as the time required for the decoding process (that is, at the same time when the decoding method information is transmitted to the decoding processing function unit 8a-2). The decoding preparation is started based on the designation of the decoding method information.

  Hereinafter, similarly, when each decoding processing function unit receives the decoding method information from the preceding decoding processing function unit, the next decoding processing function after the same time as the time required for the decoding processing has elapsed from the time when the decoding method information was received. At the same time as the decoding scheme information is transmitted to the part, decoding preparation is started based on the designation of the decoding scheme information. Each of the decoding processing function units sequentially performs such processing, and the decoding scheme information is transmitted to the Nth decoding processing function unit 8a-N to complete the preparation for decoding.

  The decoding processing function unit 8a-1 receives the input frame, executes decoding processing, and outputs the processed frame to the subsequent decoding processing function unit 8a-2. Decoding processing function unit 8a-2,..., 8a- (N-1) receives the frame output from the preceding decoding processing function unit, executes decoding processing, and processes the processed frame to the next decoding process. Output to the functional part. The decoding processing function unit 8a-N receives the frame output by the preceding decoding processing function unit 8a- (N-1), executes decoding processing, and outputs the processed frame as an output frame of the decoding processing device 1a. .

  In this way, the decoding process is executed in the order of N decoding processing function units 8a-1, 8a-2,..., 8a- (N-1), 8a-N, and the Nth decoding processing function unit 8a- The decoding process is performed by the decoding method designated up to N and a frame is output.

  The operation of this embodiment will be described with reference to FIGS. 5 and 6A to 6C. FIG. 5 shows the input of the frame and decoding method information from the previous stage and the output to the next stage and the start of setting in the k (k is an integer of 1, 2,..., N) th decoding processing function unit 8a-k. 5 is a timing chart showing the relationship between the time of completion and the time of completion. FIGS. 6A to 6C are timing charts for explaining three cases in which the required time TdS for the decoding process and the required time TsuS for setting the decoding method are different. The decoding processing function unit 8a-k1, the decoding processing function Part 8a-k2, decoding processing function part 8a-k3 (k1, k2, k3 are integers of 1, 2,..., N), the relationship between the start time and completion time of the decoding method, and the TdS, TsuS and frame It is a timing chart which shows the relationship of the minimum space | interval.

  .., 8a- (N-1), and 8a-N, the required times for the decoding processing function units 8a-1, 8a-2,..., 8a-N are respectively known values TdS (1) and TdS (2). ,..., TdS (N-1), TdS (N), and setting of the decoding method in the decoding processing function units 8a-1, 8a-2,..., 8a- (N-1), 8a-N. Are defined as known values TsuS (1), TsuS (2),..., TsuS (N−1), and TsuS (N), respectively.

Known burst overhead time Tboh from the beginning of the received burst signal to the beginning of the frame in the burst signal, known in-device delay time Tdint from when the frame arrives at the receiving side device 1a until it is input to the decoding processing function unit 8a , And the burst signal reception start time Treceive_ (i), the processing start scheduled time Tr0S (1) (i) in the decoding processing function unit 8a-1 of the received frame received from the ONU (i) is It is expressed as
Tr0S (1) (i) = Treceive_ (i) + Tboh + Tdint
(12)

Assuming that a known time required from the reception of the ONU identification information in the decoding method determination function unit 7a to the specification of the decoding method to the decoding processing function unit 8a is Tjd, the reception time management function unit 6a performs the ONU (i The time Tr1S (1) (i) at which the reception slot signal corresponding to the reception frame received from (1) should be set to the logic level H is calculated as follows.
Tr1S (1) (i) = Tr0S (1) (i) -Tjd
= {Treceive_ (i) + Tboh + Tdint} -Tjd (13)

Further, when the reception time width Tlength_ (i) of the burst signal received from the ONU (i) is used, the scheduled reception completion time Ts0S (1) in the decoding processing function unit 8a-1 of the received frame received from the ONU (i) (I) becomes following Formula.
Ts0S (1) (i) = Tr0S (1) (i) + Tlength_ (i)
= Treceive_ (i) + Tboh + Tdint + Tlength_ (i)
(14)

The reception time management function unit 6a uses the time Tjd required from the reception of ONU identification information in the decoding method determination function unit 7a to the specification of the decoding method to the decoding processing function unit 8a. The time Ts1S (1) (i) to be set to the level L is calculated as follows.
Ts1S (1) (i) = Ts0S (1) (i) -Tjd = {Treceive_ (i)
+ Tboh + Tdint + Tlength_ (i)}-Tjd (15)

  The reception slot signal output from the reception time management function unit 6a changes from the logic level L to the logic level H at time Tr1S (1) (i) corresponding to the reception of the frame from the ONU (i), and thereafter When the time Ts1S (1) (i) is reached, the logic level H changes to the logic level L.

  Similarly, the reception slot signal transitions from the logic level L to the logic level H at time Tr1S (1) (i + 1) corresponding to the frame reception from the ONU (i + 1), and at time Ts1S (1) (i + 1). Transition from logic level H to logic level L.

  The ONU (i) identification information is valid until time Ts1S (1) (i), and the ONU (i + 1) identification information starts to be output at time Ts1S (1) (i) and time Ts1S (1) (i + 1). ) Is effective. The transition from the logical level H to the logical level L of the reception slot signal gives an opportunity for the decoding method determination function unit 7a to start the decoding method determination operation based on the ONU identification information output from the reception time management function unit 6a. . For example, at time Ts1S (1) (i), the decoding method determination function unit 7a is given an opportunity to start the determination operation of the decoding method corresponding to ONU (i + 1).

The decoding method determination function unit 7a receives the identification information of the ONU from the reception time management function unit 6a, and designates the decoding method corresponding to the identification information to the decoding processing function unit 8a. The decoding method determination function unit 7a receives the identification information of the ONU (i + 1) at the time Ts1S (1) (i), so the time Ts2S (1) (i) at which the decoding method information corresponding to the ONU (i + 1) is output is determined. After the required time Tjd, the following equation is obtained.
Ts2S (1) (i) = Ts1S (1) (i) + Tjd
= (Ts0S (1) (i) -Tjd) + Tjd = Ts0S (1) (i)
... (16)

  That is, the decoding method information corresponding to the ONU (i + 1) is received at the scheduled time Ts0S (1) (i) = Ts2S (1) (i) when the decoding processing function unit 8a-1 completes reception of the frame from the ONU (i). The data is input to the decryption processing function unit 8a-1.

The scheduled decoding process completion time Te0S (1) (i) of the frame from the ONU (i) in the decoding processing function unit 8a-1 is represented by the following equation.
Te0S (1) (i) = Ts0S (1) (i) + TdS (1)
= Treceive_ (i) + Tboh + Tdint + Tlength_ (i)
+ TdS (1) (17)

  The decryption processing function unit 8a-1 performs the ONU at time Te0S (1) (i) after the same time as the time TdS (1) required for decryption processing from the time Ts0S (1) (i) received the decryption method information. Decoding preparation is started based on the designation of the decoding method information corresponding to (i + 1).

  At this time Te0S (1) (i), the decoding processing function unit 8a-1 has already completed the decoding process up to the end of the frame from the ONU (i), and the decoding method information corresponding to the ONU (i) Thus, the preparation for decoding can be started based on the decoding method information corresponding to ONU (i + 1) without affecting the decoding processing of the frame from ONU (i).

The time Tsu0S (1) (i + 1) when the decoding preparation corresponding to ONU (i + 1) of the decoding processing function unit 8a-1 is completed is after TsuS (1) of the time Te0S (1) (i) at which the preparation for decoding is started. Because there is, it is given by the following formula.
Tsu0S (1) (i + 1) = Te0S (1) (i) + TsuS (1)
= Ts0S (1) (i) + TdS (1) + TsuS (1)
= Treceive_ (i) + Tboh + Tdint + Tlength_ (i)
+ TdS (1) + TsuS (1) (18)

The scheduled reception start time (scheduled process start time) Tr0S (1) (i + 1) of the frame from the ONU (i + 1) in the decoding processing function unit 8a-1 is expressed by the following equation.
Tr0S (1) (i + 1) = Treceive_ (i + 1) + Tboh + Tdint
... (19)

The condition for the decoding processing function unit 8a-1 to complete the preparation for decoding before the start of frame reception from the ONU (i + 1) is as follows.
Tr0S (1) (i + 1) -Tsu0S (1) (i + 1)
= {Treceive_ (i + 1) + Tboh + Tdint}
-{Treceive_ (i) + Tboh + Tdint
+ Tlength_ (i) + TdS (1) + TsuS (1)}
= {Treceive_ (i + 1)}-{Treceive_ (i)
+ Tlength_ (i) + TdS (1) + TsuS (1)} ≧ 0
... (20)

Transposing equation (20) yields:
{Treceive_ (i + 1)}-{Treceive_ (i)
+ Tlength_ (i)} ≧ {TdS (1) + TsuS (1)}
... (21)

  From the equation (21), the reception interval between the burst signal and the next burst signal indicates that the decoding processing function unit 8a-1 requires a time TsuS (1) required for setting the decoding method and a time required for decoding processing TdS ( It can be seen that the sum should be greater than or equal to 1).

Similarly, the scheduled reception start time (scheduled process start time) Tr0S (2) (i + 1) of the frame from the ONU (i + 1) in the decoding processing function unit 8a-2 can be expressed as the following equation.
Tr0S (2) (i + 1) = Treceive_ (i + 1) + Tboh + Tdint
+ TdS (1) (22)

  The time at which the decoding processing function unit 8a-1 transmits the decoding method information to the decoding processing function unit 8a-2 is the time required for decoding processing TdS (1) from the time when the decoding method information is received from the decoding method determination function unit 7a. After the same time. That is, at the frame processing completion scheduled time Te0S (1) (i) from the ONU (i) of the decoding processing function unit 8a-1, the decoding scheme information of the ONU (i + 1) is decoded from the decoding processing function unit 8a-1. Is input to the unit 8a-2.

The decryption processing function unit 8a-2 receives the time Ts0S (1) (i) + TdS (2) after the same time as the time TdS (2) required for the decryption process from the time Te0S (1) (i) received the decryption method information. ) Starts preparation for decoding based on the designation of the decoding method information.
Ts0S (1) (i) + TdS (2) = {Treceive_ (i) + Tboh
+ Tdint + Tlength_ (i) + TdS (1)} + TdS (2)
(23)

The time Tsu0S (2) (i + 1) when the decoding preparation corresponding to the ONU (i + 1) of the decoding processing function unit 8a-2 is completed is the TsuS (2) (i) + TdS (2) TsuS ( 2) Since it is later, it is given by the following equation.
Tsu0S (2) (i + 1) = {Treceive_ (i) + Tboh + Tdint
+ Tlength_ (i) + TdS (1)} + TdS (2) + TsuS (2)
... (24)

The condition for the decoding processing function unit 8a-2 to complete the preparation for decoding by the start of frame reception from the ONU (i + 1) is as follows.
Tr0S (2) (i + 1) −Tsu0S (2) (i + 1) ≧ 0 (25)

From the equation (25), the following equation is established.
{Treceive_ (i + 1)}-{Treceive_ (i)
+ Tlength_ (i)} ≧ {TdS (2) + TsuS (2)}
... (26)

  From the equation (26), the reception interval between the burst signal and the next burst signal indicates that the decoding processing function unit 8a-2 requires a required time TsuS (2) required for setting the decoding method and a required time TdS ( It can be seen that the sum should be equal to or greater than 2).

Similarly, the condition for completing the preparation for decoding before the start of frame reception from the ONU (i + 1) in the decoding processing function unit 8a-k is as follows.
{Treceive_ (i + 1)}-{Treceive_ (i)
+ Tlength_ (i)} ≧ {TdS (k) + TsuS (k)}
... (27)

  That is, according to the present embodiment, the burst signal and the next burst signal are equal to or greater than the sum of the time required for setting the decoding method and the time required for the decoding process in any decoding processing function unit. The time Tr1S (1) (i) at which the reception slot signal should be at the logic level H and the time Ts1S (1) (i) at which the reception slot signal should be at the logic level L are calculated by setting the reception interval between them. By doing so, the preparation for decoding can be completed by the start of frame reception.

In this embodiment, the time Tslot_LH at which the reception slot signal transitions from the logic level L to the logic level H is set as the time Tr1S (1) (i). Also good.
Ts1S (1) (i + 1)>Tslot_LH> Ts1S (1) (i)
... (28)

  The shortest interval from the completion of burst signal reception to the start of reception of the next burst signal is {Tsu + Tddec} in the first embodiment, that is, the time required for setting the decoding method in the decoding processing function unit 8 and decoding This is the sum of the time required for processing. In contrast, in the present embodiment, the shortest interval from the completion of burst signal reception to the start of reception of the next burst signal is defined as {TdS (k) + TsuS (k)} (k = 1, 2, .., N), that is, the sum of the time required for setting the decoding method and the time required for the decoding process can be shortened to the maximum value obtained for each decoding processing function unit. This has the effect of increasing the throughput of the decoding process.

  Furthermore, in the present embodiment, the finer the granularity of each decoding processing step of the decoding processing function unit 8a, the shorter the time required for setting the decoding method, and the shorter the time required for decoding processing per step. Therefore, the interval from the completion of burst signal reception to the start of reception of the next burst signal can be further shortened, which has the effect of increasing the throughput of decoding processing.

  Two times calculated by the reception time management function unit 6a, that is, a time Tr1S (1) (i) at which the reception slot signal should be at the logic level H and a time Ts1S (1) (i) at which the reception slot signal should be at the logic level L ), As described above, the decoding processing function units 8a-1, 8a-2,..., 8a- (N-1), 8a-N, the decoding processing function units 8a-1, 8a-2, .., 8a- (N-1), 8a-N required time for decoding processing, decoding processing function units 8a-1, 8a-2, ..., 8a- (N-1), 8a- It does not depend on the time required for setting the N decoding methods and the time required for the decoding processing of the entire decoding processing function unit 8a.

  Even if the decoding processing step of the decoding processing function unit 8a is finely divided, the number of times to calculate may be two, Tr1S (1) (i) and Ts1S (1) (i), and the reception time management function unit 6a The number of times to calculate does not increase, and the time value does not change. That is, according to the configuration of the present embodiment, it is possible to appropriately determine the configuration of the decoding processing function unit 8a without increasing the time calculation load.

  Thereby, in the present embodiment, the sum of the time required for setting the decoding method and the time required for the decoding process can be averaged at each decoding process step, and the decoding process step in which this sum becomes extremely large By determining the configuration of the decoding processing function unit 8a so as not to occur, the reception interval from the completion of burst signal reception to the start of reception of the next burst signal can be shortened, which has the effect of increasing the decoding processing throughput.

  In the configuration of the present embodiment, if the decoding method determination function unit 7a holds the decoding method information instructed to the first decoding processing function unit 8a-1 of the decoding processing function unit 8a during the valid period, the decoding is performed. Unless the scheme information is changed to another value, the decoding scheme information transmitted from the preceding decoding processing function unit to the succeeding decoding processing function unit is also maintained at the same value. Therefore, it is not necessary to hold the decoding method information in each decoding processing function unit 8a-1, 8a-2,..., 8a- (N-1), 8a-N, and the input decoding method information is decoded as it is. Since it only needs to be reflected in the setting for processing, there is an effect that the configuration of each decoding processing function unit 8a-1, 8a-2,..., 8a- (N-1), 8a-N can be simplified. .

[Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 7 is a block diagram showing the configuration of the decoding processing apparatus according to the third embodiment of the present invention. The same components as those in FIGS. 1 and 4 are given the same reference numerals.

  The decoding processing device 1b according to the present embodiment includes an input terminal 2, an output terminal 3, a scheduled reception start time calculation unit 4, a reception time management function unit 6a, a decoding method determination function unit 7b, and a decoding processing function unit. 8b. In FIG. 7, 73 is a terminal to which the decoding method determination function unit 7b sends a decoding method information enable signal, and 83 is a terminal from which the decoding processing function unit 8b receives the decoding method information enable signal.

  The difference between the present embodiment and the second embodiment is that the decoding processing function units 8b-1, 8b-2, ..., 8b- (N-1), 8b-N hold the decoding method information. , 84- (N-1), 84-N, and registers 84-1, 84-2,..., 84- ( N-1) and 84-N indicate that the decoding method information enable signal indicating the timing at which the decoding method information is latched is output from the decoding method determination function unit 7b together with the decoding method information.

  Similarly to the second embodiment, the decoding method determination function unit 7b transmits the decoding method information to the decoding processing function unit 8a-1, and simultaneously decodes the decoding method information enable signal indicating the timing at which the decoding method information is latched. It transmits to the processing function part 8a-1.

  After receiving the decoding method information and the decoding method information enable signal from the decoding method determination function unit 7b, the decoding processing function unit 8a-1 sends the decoding processing function unit 8a-1 to the decoding processing function unit 8a-2 after elapse of the same time as the time required for the decoding processing. The decoding method information and the decoding method information enable signal are transmitted, and the setting of the decoding method is started based on the decoding method information held by the internal decoding method register 84-1.

Hereinafter, similarly, the decoding processing function units 8b-2,..., 8b- (N-1) perform the decoding process from the time when the decoding method information and the decoding method information enable signal are received from the preceding decoding processing function unit. After the elapse of the same time as the required time, the decoding method information and the decoding method information enable signal are transmitted to the subsequent decoding processing function unit and the internal decoding method registers 84-2, ..., 84- (N-1). The setting of the decoding method is started on the basis of the decoding method information held by. In addition, the decoding processing function unit 8b-N receives the decoding method information and the decoding method information enable signal from the preceding decoding processing function unit 8b- (N-1) and after the same time as the time required for the decoding processing has elapsed. The setting of the decoding method is started based on the decoding method information held by the decoding method register 84-N.
Since other operations are the same as those in the second embodiment, description thereof will be omitted.

  According to the configuration of the present embodiment, the decoding method information output from the decoding method determination function unit 7b and transmitted to the decoding processing function unit 8b can be shortened to 1 bit width. Therefore, in the present embodiment, it is possible to fix the level of the wiring for transmitting the decoding method information or to use it for the transmission of other signals other than the time for transmitting the decoding method information.

  In the first to third embodiments, an example in which the present invention is applied to an EPON (Ethernet (registered trademark) Passive Optical Network) system has been described. However, the present invention is not limited to this. As long as it is a communication mode in which the reception side device manages the reception time of the signal by the transmission / reception procedure in which the transmission side device transmits the signal in accordance with the transmission start time information and the transmission time length information notified to the transmission side device, other The present invention can be applied to other communication systems. When applied to other communication systems, as in the case of the EPON system, the decoding processing device is provided in the receiving side device.

  The decryption processing devices 1, 1a, and 1b described in the first to third embodiments can be realized by hardware, or can be realized by software using a computer including a CPU and a storage device. . When implemented by software using a computer, the CPU executes the processes described in the first to third embodiments in accordance with a program stored in the storage device.

  The present invention can be applied to a technique in which a receiving-side apparatus performs a signal decoding process by dynamically switching a decoding method.

  DESCRIPTION OF SYMBOLS 1,1a, 1b ... Decoding processing apparatus, 2 ... Input terminal, 3 ... Output terminal, 4 ... Reception scheduled start time calculation part, 6, 6a ... Reception time management function part, 7, 7a, 7b ... Decoding system determination function part 8, 8a, 8a-1 to 8a-N, 8b, 8b-1 to 8b-N ... Decoding processing function unit, 60 to 65, 70 to 73, 80 to 83 ... Terminals, 84-1 to 84-N ... Decryption method register.

Claims (8)

In a decoding processing apparatus that decodes a reception signal corresponding to a plurality of encoding schemes and whose reception start scheduled time and encoding scheme are known,
Based on the transmission start time information and the transmission time length information to be notified to each transmission side device, reception time management means for managing the scheduled reception start time of the signal received from each transmission side device;
A decoding method determination means for determining a decoding method from identification information of a transmitting device of a signal received at the scheduled reception start time;
Decoding processing means for decoding the signal received at the scheduled reception start time based on the decoding method information output from the decoding method determination means;
The reception time management means determines the identification information of the transmitting device of the signal received at the scheduled reception start time based on the scheduled reception start time, prior to the scheduled processing start time of the decoding processing means. A decoding processing apparatus characterized by completing preparation of decoding processing of the decoding processing means before the scheduled processing start time by outputting to a decoding method determination means. The decoding processing device according to claim 1,
The reception time management unit determines the decoding method after the decoding method determination unit receives the identification information of the transmission side device, and the decoding processing unit receives the decoding method information and completes the preparation for performing the decoding process. A decoding processing apparatus, wherein identification information of a transmitting side device is output to the decoding method determination means by going back from the scheduled processing start time by a time longer than a required time. In the decoding processing apparatus according to claim 1 or 2,
The decoding processing means has a plurality of decoding processing function means for each decoding processing step obtained by dividing the decoding processing,
Each decoding processing function means executes signal processing in a predetermined order and outputs the processed signal to the next decoding processing function means. The decryption processing device according to claim 3,
Each decoding processing function means transmits the decoding method information output from the decoding method determination means in the same order as the order of signal processing, and sets the decoding method in the order in which the decoding method information is transmitted. A decoding processing device. The decoding processing device according to claim 4, wherein
Each decoding processing function means includes a holding means for holding the transmitted decoding method information. In the decoding processing apparatus according to any one of claims 1 to 5,
The decoding processing device according to claim 1, wherein when the signal received from the transmission side device is not encoded, the decoding processing means does not perform the decoding processing of this signal. The decoding processing device according to any one of claims 1 to 6,
The decryption processing apparatus, wherein the decryption processing is decryption processing of an encrypted signal. The decoding processing device according to any one of claims 1 to 7,
A decoding processing device that performs decoding processing of an EPON received frame.

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