JPS59212048A - Data transmission control system - Google Patents

Data transmission control system

Info

Publication number
JPS59212048A
JPS59212048A JP8594083A JP8594083A JPS59212048A JP S59212048 A JPS59212048 A JP S59212048A JP 8594083 A JP8594083 A JP 8594083A JP 8594083 A JP8594083 A JP 8594083A JP S59212048 A JPS59212048 A JP S59212048A
Authority
JP
Japan
Prior art keywords
transmission
preamble
length
data
collision
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP8594083A
Other languages
Japanese (ja)
Inventor
Takeshi Yasuda
安田 猛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP8594083A priority Critical patent/JPS59212048A/en
Publication of JPS59212048A publication Critical patent/JPS59212048A/en
Pending legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00Data switching networks
    • H04L12/28Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
    • H04L12/40Bus networks
    • H04L12/407Bus networks with decentralised control
    • H04L12/413Bus networks with decentralised control with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Time-Division Multiplex Systems (AREA)
  • Small-Scale Networks (AREA)

Abstract

PURPOSE:To perform priority control over a CSMA/CD (carrier sense multiple access/condition detection) system by determining the length of a preamble according to an addressee address. CONSTITUTION:When there is a transmission request, the preamble length is determined by the addressee address. When a transmission line is free, a preamble is transmitted; if a collision occurs at the time of the completion of the transmission of preambles, back-off operation is performed, and when not, data is transmitted. Further, if there is no collision after 2DR (D: maximum delay time, R: transmission rate) bits corresponding to maximum network length are transmitted even when all preambles are not transmitted, the transmission of the preambles is stopped and the data is sent out.

Description

【発明の詳細な説明】 技術分野 本発明は、複数の伝送装置が同じ伝送路を共有してデー
タ伝送全行ガう、バス状ネットワークのデータ伝送制御
方式に関する。
TECHNICAL FIELD The present invention relates to a data transmission control system for a bus-like network in which a plurality of transmission devices share the same transmission path for all data transmission.

従来技術 従来、バス状ネットワークにおけるデータ伝送制御はC
8Mk7CD (Carrier SenseMu口1
ple Access /Co11ision Det
ection )方式が多くとられてきた。
Prior Art Conventionally, data transmission control in a bus-like network was performed using C.
8Mk7CD (Carrier SenseMu mouth 1
ple Access /Co11ision Det
Many methods have been adopted.

COMA/CD方式を第1図のフローチャートを参照し
て説明する。
The COMA/CD method will be explained with reference to the flowchart in FIG.

ネットワークに接続されている伝送装置よシ送信費求が
生じると、ステップ21において伝送路が空いているか
どうか判断し、他の機器が伝送中で伝送路が窒いていな
い時は空くまで待ち、伝送路が空いてからステップ22
において送信を開始する。しかしC8Mk7CD方式は
、伝送路が空いていれはどの伝送装置でも送信開始する
ことができ。
When a transmission fee request is generated by a transmission device connected to the network, it is determined in step 21 whether the transmission line is free or not. If the transmission line is not choked due to other equipment transmitting, it waits until the transmission line is free and transmits the data. Step 22 after the road is clear
Transmission starts at . However, in the C8Mk7CD system, any transmission device can start transmitting as long as the transmission path is empty.

同時刻に複数の伝送装置が送信を開始すると、伝送路上
でデータの衝突が生じる。故に送信を開始した伝送装置
自身がステップ23.ステップ24において伝送路上の
信号を監視し、衝突の検出を行ない、衝突を検出すると
ただちに送信を中止するか、又はステップ26に示す如
く衝突を強めるためにジャム送信を行なった後、ステッ
プ27において再送後の再衝突を防止する為に互いにラ
ンダム費累を持つ遅延時間(バックオフアルゴリズムに
よる遅延時間)だけ待機してステップ21にもどυ再送
を行う。
When multiple transmission devices start transmitting at the same time, data collision occurs on the transmission path. Therefore, the transmission device itself that started the transmission performs step 23. In step 24, signals on the transmission path are monitored and collisions are detected, and when a collision is detected, transmission is immediately stopped, or jam transmission is performed to intensify the collision as shown in step 26, and then retransmission is performed in step 27. In order to prevent future re-collision, υ retransmission is performed again at step 21 after waiting for a delay time (delay time due to the back-off algorithm) in which both have random costs accumulated.

しかしこの従来のC8MkyCD方式においては特に重
負荷時には衝突が生じゃすくなり、衝突も二重三重に生
じる場合もおこシ、伝送しスポンス及 3− び伝送効率が著しく低下する。このためリアルタイム性
伝送を要求する機器は使用できなくなるといった欠点が
あった。
However, in this conventional C8MkyCD system, collisions are likely to occur especially when the load is heavy, and collisions may occur double or triple, resulting in a significant drop in transmission response and transmission efficiency. This has resulted in the disadvantage that equipment requiring real-time transmission cannot be used.

目的 本発明は、上述の点に鑑みてなされたもので。the purpose The present invention has been made in view of the above points.

データ送出に先だって伝送路の安定化と同期化の為に送
出するプリアンプルの長さを設定された装置アドレスに
よって決め、衝突が生じた時決まったプリアンプルを出
しつづけて最後に残ったものが伝送路を獲得することに
よシ、股?アドレスによって決定する優先度の高い装置
の再送を防止することにより、効率よい伝送とリアルタ
イム伝送を容易にできる。と同時に従来のC8MkyC
D方式とも互換性を可能にすることを目的とする。
Prior to data transmission, the length of the preamble to be sent to stabilize and synchronize the transmission path is determined by the set device address, and when a collision occurs, the length of the preamble to be sent is determined by the device address, and when a collision occurs, the length of the preamble to be sent is determined, and when a collision occurs, the length of the preamble to be sent is determined, and the last remaining one is Is it okay to acquire a transmission line? By preventing retransmission of devices with high priority determined by the address, efficient transmission and real-time transmission can be facilitated. At the same time, the conventional C8MkyC
The purpose is to enable compatibility with the D method.

実施例 以下本発明の一実施例について図面を参照して 4− 砦、明する。Example An embodiment of the present invention will be described below with reference to the drawings. 4- The fort is revealed.

第2図は本実施例伝送装置のブロック図であシ。FIG. 2 is a block diagram of the transmission device of this embodiment.

図において16は装置間を接続しネットワークを構成す
るバス状伝送路、1は伝送路上の信号を受信するレクー
バ、2は受信信号を復調するフェーズ・エンコーダ、4
は送信データを変調するフェーズ・エンコーダ、3は送
信信号によシ伝送路16をドライブするドライバ、5は
送信データの衝突検出を行う衝突検出部、7は送・受信
データのC几Ci処理するCRC処理部、6はCRC処
理部7への入力を送信と受信とにわけるセレクタ、。
In the figure, 16 is a bus-like transmission line that connects devices to form a network, 1 is a receiver that receives signals on the transmission line, 2 is a phase encoder that demodulates the received signal, and 4
is a phase encoder that modulates the transmission data; 3 is a driver that drives the transmission line 16 according to the transmission signal; 5 is a collision detection unit that detects collisions of transmission data; and 7 is for processing the transmission and reception data. CRC processing section 6 is a selector that divides input to CRC processing section 7 into transmission and reception.

8は送受信を行うシフトレジスタ、9は送受信用FIF
Oバッファ、10は伝送装置をコントロールするコント
ローラCPU、11は伝送路16の空を検出する伝送路
空検出部、12は伝送路16にCRC,データ、プリア
ンプル信号のうちどの信号を送出するかを選択するため
のセレクタ、13はプリアンプルを成虫ずるプリアンプ
ル発生器。
8 is a shift register for transmitting and receiving, 9 is a FIF for transmitting and receiving.
O buffer, 10 is a controller CPU that controls the transmission device, 11 is a transmission line empty detection unit that detects whether the transmission line 16 is empty, and 12 is a signal that determines which signal among CRC, data, and preamble signals is sent to the transmission line 16. 13 is a preamble generator that generates a preamble.

14は設定されたアドレスによってプリアップル長を決
めるプリアンプル長制御部、15は伝送装置毎に割g当
てられたアドレスを設定するアドレス設定部である。
14 is a preamble length control section that determines the preamble length based on the set address; 15 is an address setting section that sets an address assigned to each transmission device.

次に本実施例の動作について第3図の70−チャートを
用いて詳細に説明する。
Next, the operation of this embodiment will be explained in detail using chart 70 in FIG.

コントローラ10に送信要求が生じるとステップ30に
進み、コントローラ(CPU)10はプリアンプル長制
御部14にプリアンプルの送信を指示する。プリアンプ
ル長制御部14扛アドレス設定部15に設定されている
アドレスを取)込み、これを基に例えば装置の優先順位
に応じた送出プリアンプル長を設定する(ステップ34
)。アドレスはネットワークに接続されている装置が電
話番号のように各装置ごとに持つ番号であるから。
When a transmission request is issued to the controller 10, the process proceeds to step 30, where the controller (CPU) 10 instructs the preamble length control unit 14 to transmit a preamble. The preamble length control unit 14 takes in the address set in the address setting unit 15, and based on this, sets the transmission preamble length according to the priority of the device, for example (step 34).
). An address is a number assigned to each device connected to a network, like a telephone number.

各伝送装置固有のプリアンプル長が設定される。A preamble length unique to each transmission device is set.

次に伝送路空検出部11において伝送路が空いているか
確認し、もし空いていなければ(ステップ36−N)空
くまで待ち、空いていれは(ステップ36−Y)プリア
ンプル長制御部14はプリアンプル発生器13に指示し
てプリアングルを送出させる。プリアンプル発生器13
で出方されたプリアンプルはセレクタ12を通夛フェー
ズ・エンコーダ4で変調されドライバー3で伝送路15
に出力される(ステップ38)。そして設定されたプリ
アンプル長のプリアンプルの送出終了(ステップ4O−
Y)、又はプリアンプルク送出後2DBビット送出した
かを監視する(ステップ40.42)。
Next, the transmission line empty detection unit 11 checks whether the transmission line is empty, and if it is not empty (step 36-N), wait until it becomes empty, and if it is empty (step 36-Y), the preamble length control unit 14 The preamble generator 13 is instructed to send out a preangle. Preamble generator 13
The preamble outputted from the selector 12 is modulated by the phase encoder 4, and then sent to the transmission line 15 by the driver 3.
(step 38). Then, the transmission of the preamble of the set preamble length is completed (step 4O-
Y), or whether 2 DB bits have been sent after sending the preamble (step 40.42).

ここで2DRというのはプリアングルがネットワークの
最長を往復できるビット数で%Dはネット 7− ワークの最大遅延時間り秒〕、Rは伝送速度〔ビット/
秒〕である。2D几ビレトは2D几だけプリアンプル送
出後衝突を確認し、衝突していなければ以後理論的には
衝突がおこらないことを意味するビット数である。
Here, 2DR is the number of bits that the pre-angle can travel back and forth over the longest length of the network, %D is the maximum delay time of the network (in seconds), and R is the transmission rate [bits/sec].
seconds]. The 2D filter is a bit number that means that only the 2D filter checks for a collision after sending the preamble, and if no collision occurs, theoretically no collision will occur thereafter.

ステップ42でプリアンプルの2DRビツト送出を検出
すると(ステップ42−Y)、衝突検出部5で衝突を確
認し、衝突していなければ(ステップ44−N)プリア
ンプルの送出全中止して(ステップ46)、データの送
出を行ない(ステップ48)、データの送出が終了する
と送信処理を終了する。衝突検出部5で衝突が検出され
ている時(ステップ44−Y )は同時に他の機器も送
信を開始しているので2DRビツトカウタをクリアして
(ステップ54)、再び2DBビット分のプリアンプル
送出を続けるべくステップ40に戻 8− る。そこで又2DRビツト送出を検出すると先の処理を
行ない、プリアンプル畏制御部14で設電L7を分のプ
リアンプルを送出する。プリアンプル長制御部14で設
定部のプリアンプル送出終了を検出すると(ステップ4
O−Y)、i実検出部5で衝突を確認し、衝突していな
ければ(ステップ50− N ) スf ツブ48へ進
ミ、データヲFIF。
When the transmission of 2DR bits of the preamble is detected in step 42 (step 42-Y), the collision detection unit 5 confirms the collision, and if there is no collision (step 44-N), the transmission of the preamble is completely stopped (step 42-Y). 46), data is transmitted (step 48), and when the data transmission is completed, the transmission process is terminated. When the collision detection unit 5 detects a collision (step 44-Y), since other devices are also starting transmission at the same time, the 2DR bit counter is cleared (step 54) and the preamble for 2 DB bits is sent again. Return to step 40 to continue. Then, when the transmission of 2DR bits is detected again, the above processing is performed, and the preamble control section 14 transmits a preamble corresponding to the power supply L7. When the preamble length control section 14 detects the completion of preamble transmission from the setting section (step 4),
(O-Y), I check the collision in the actual detection unit 5, and if there is no collision (step 50-N), proceed to block 48 and save the data.

バッファ9.シフトレジスタ8全通してセレクタ12に
送出し、セレクタ12′ではプリアンプル発生器13よ
シのデータに変えてシフトレジスタ8よりのデータをフ
ェーズ・エンコーダ4に送り、フェーズ・エンコーダ4
はドライバ3を介して送信データを伝送路16へ送出す
る。衝突している時は(ステップ5O−Y)自装置よシ
送出先優先度の高い装置よりの送信要求が発生している
場合であるので、バックオフアルゴリズムによって決定
された時間分待ち(ステップ52)、その後ステップ3
6に戻シ再送を行なう。ここでパックオフアルゴリズム
i08MAzcD 方式において、パケット(プリアン
プルを含む送信情報)衝突の検出により送信を中止して
から再送を開始するまでの時間を決めるアルゴリズムで
あり、この時間は乱数で選ばれる。  ゛ 効果 以上説明したように本発明によればプリアップルの長さ
を伝送装置のアドレスにより決定することによシ、伝送
装置によって優先度を持たせることができ、伝送を効率
よく、リアルタイム性も可能にすることができる。又言
うまでもな〈従来のプリアンプル長固定のC8MA/C
D方式とも互換性を可□能にすることができる。
Buffer 9. The data from the shift register 8 is sent to the selector 12 through the entire shift register 8, and the selector 12' changes the data from the preamble generator 13 to the data from the shift register 8, and sends the data from the shift register 8 to the phase encoder 4.
sends the transmission data to the transmission line 16 via the driver 3. If there is a collision (step 5O-Y), this means that there is a transmission request from a device with a higher destination priority than the own device, so the process waits for the time determined by the backoff algorithm (step 52). ), then step 3
6 and performs retransmission. Here, the pack-off algorithm i08MAzcD is an algorithm that determines the time from when transmission is stopped by detecting a packet (transmission information including preamble) collision to when retransmission is started, and this time is selected using a random number.゛Effects As explained above, according to the present invention, by determining the length of the pre-apple based on the address of the transmission device, priority can be given depending on the transmission device, making transmission efficient and real-time. can be made possible. Needless to say, <C8MA/C with conventional fixed preamble length
Compatibility with the D method can also be made possible.

【図面の簡単な説明】[Brief explanation of drawings]

第1図は従来方式の動作フローチャート。 第2図は本発明の一実施例の伝送装置のブロック図。 第3図は実施例伝送装置の動作フローチャートである。 図において、1・・・レシーバ、2・・・フェーズ・デ
コーダ% 3・・・トライバ、4・・・フェーズ・エン
コーダ、5・・・衝突検出部、6・・・セレクタ、7・
・・CkLC処理部、8・・・シフトレジスタ、9・・
・FIFOバッファ、10・・・コントローラCPU、
11・・・伝送路空検出部、讐2・・・セレクタ、13
・・・プリアンプル発生器、14・・・プリアンプル長
制御部、15・・・アドレス設定部、16・・・伝送路
である。 11− 12−
FIG. 1 is an operation flowchart of the conventional method. FIG. 2 is a block diagram of a transmission device according to an embodiment of the present invention. FIG. 3 is an operation flowchart of the embodiment transmission device. In the figure, 1... Receiver, 2... Phase decoder%, 3... Triver, 4... Phase encoder, 5... Collision detection section, 6... Selector, 7...
...CkLC processing unit, 8...shift register, 9...
・FIFO buffer, 10...controller CPU,
11...Transmission line empty detection unit, enemy 2...Selector, 13
... preamble generator, 14 ... preamble length control section, 15 ... address setting section, 16 ... transmission line. 11- 12-

Claims (2)

【特許請求の範囲】[Claims] (1)複数の伝送装置が同じ伝送路を共有してデータ伝
送を行なうパス状ネットワークにおいて。 前記伝送装置に転送するパケットの先頭にプリアンプル
を附加するプリアンプル発生手段と、該プリアンプル発
生手段で発生させる前記プリアンプルの長さを制御する
プリアンプル長制御手段と。 アドレスを設定するアドレス設定部とを備え、前記プリ
アンプル長制御手段は前記アドレス設定部に設定されて
いるアドレスによシ前記発生させるプリアンプルの長さ
を決定することを特徴とするデータ伝送制御方式。
(1) In a path-like network in which multiple transmission devices share the same transmission path to transmit data. Preamble generation means for adding a preamble to the beginning of a packet to be transferred to the transmission device; and preamble length control means for controlling the length of the preamble generated by the preamble generation means. an address setting section for setting an address, and the preamble length control means determines the length of the preamble to be generated according to the address set in the address setting section. method.
(2)  アドレス設定部に設定されるアドレスは伝送
装置の優先順位によシ決定されることを特徴とする特許
請求の範囲第1項記載のデータ伝送制御方式。
(2) The data transmission control method according to claim 1, wherein the address set in the address setting section is determined by the priority order of the transmission device.
JP8594083A 1983-05-18 1983-05-18 Data transmission control system Pending JPS59212048A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8594083A JPS59212048A (en) 1983-05-18 1983-05-18 Data transmission control system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8594083A JPS59212048A (en) 1983-05-18 1983-05-18 Data transmission control system

Publications (1)

Publication Number Publication Date
JPS59212048A true JPS59212048A (en) 1984-11-30

Family

ID=13872753

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8594083A Pending JPS59212048A (en) 1983-05-18 1983-05-18 Data transmission control system

Country Status (1)

Country Link
JP (1) JPS59212048A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01135241A (en) * 1987-10-08 1989-05-26 Critikon Inc Communication protocol for distributed station network
WO2001037491A1 (en) * 1999-11-12 2001-05-25 Karel Maria Van Den Bergh Method and device for signal transmission avoiding collisions
JP2009065703A (en) * 1998-09-22 2009-03-26 Qualcomm Inc Method and apparatus for transmitting/receiving variable rate data

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01135241A (en) * 1987-10-08 1989-05-26 Critikon Inc Communication protocol for distributed station network
JP2009065703A (en) * 1998-09-22 2009-03-26 Qualcomm Inc Method and apparatus for transmitting/receiving variable rate data
US7961592B2 (en) 1998-09-22 2011-06-14 Qualcomm Incorporated Method and apparatus for transmitting and receiving variable rate data
WO2001037491A1 (en) * 1999-11-12 2001-05-25 Karel Maria Van Den Bergh Method and device for signal transmission avoiding collisions
BE1013134A3 (en) * 1999-11-12 2001-10-02 Den Bergh Karel Maria Van Method and apparatus for signal transmission.

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