CN101848233A - Logical link control method based on LLC sub layer of on board unit of Chinese standard ETC system - Google Patents

Abstract

The invention relates to a logical link control method based on an LLC sub layer of an on board unit of a Chinese standard ETC system. In an uplink, a logic link control state machine of the on board unit comprises two types: LLC1 and LLC3, wherein for the LLC1 type, the LLC sub layer receives an interface primitives from the MAC sub layer and gives the notification to the LLC sub layer for requesting the LLC sub layer to transfer data to an application layer, the LLC sub layer receives the interface primitives from the application layer, gives the notification to the LLC sub layer to transfer command sending requests from the application layer, and requests the LLC to transfer data to the MAC sub layer; and for the LLC3 type, the LLC sub layer receives the interface primitives from the MAC sub layer, gives the notification to the LLC sub layer and sends corresponding ACn response to indicate the LLC sub layer to transfer the interface primitives to the application layer, the application layer receives one interface primitive, and the LLC sub layer receives one interface primitive from the application layer, gives the notification to the LLC sub layer to update the internal response data, and indicates the LLC sub layer to transfer the information that whether the updating is succeed or failed to the application layer. The method of the invention has the advantages that the integration degree of circuits is high, the power consumption of the circuits is low, and the information is safer.

Description

A kind of logical link control method based on LLC sub layer of on board unit of Chinese standard ETC system

Technical field

The present invention relates to integrated circuit (IC) chip, relate in particular to a kind of chainlink control method based on LLC sub layer of on board unit of Chinese standard ETC system.

Background technology

Electronic charging system without parking is called for short ETC (Electronic Toll Collection), is a kind of automatic electronic charging system that is used for highway, bridge and tunnel that develops and promote of making great efforts in the world.ETC utilizes special-purpose short distance short-wave communication tedhnology to carry out information exchange by the lane in which the drivers should pay fees or roadside unit RSU (Road Side Unit) with board units OBU (On Board Unit), discerns vehicle automatically.Adopt electronic payment mode to finish the full automatic charging mode of toll deduction automatically.Adopt this system, traffick needn't stop in charge station and pay dues and can pass through, thereby has increased the processing capacity of charge station.Because it relates to the recovery of traffic infrastructure investment, it is again the effective means of alleviating charge station's traffic jam, and potential consumer group is huge, so each country all develops the system that ETC drops into application at first as intelligent transportation system ITS (Intelligent Transportation System) field.

The ETC system onboard unit adopts universal integrated circuit to realize on the domestic market at present.There is following deficiency in this board units: at first, there is a large amount of Elementary Function modules universal integrated circuit inside, and major part is a unwanted redundant circuit in the board units; Secondly, every integrated circuit all needs independent packaging and testing, has increased the cost of chip, and the chip inlet price is more expensive, makes that the cost of board units is higher; In addition, owing to use general purpose microprocessor, operating current is bigger, makes the board units battery on the low side service life.

Summary of the invention

The object of the present invention is to provide a kind of chainlink control method based on LLC sub layer of on board unit of Chinese standard ETC system.It is realized by following technical proposals:

In up link, the logic link control state machine of described board units comprises two types of LLC1 and LLC3, wherein:

For the LLC1 type, LLC receives the sublayer MAC.indication interface primitive from MAC (MediumAccess Control) sublayer, notice LLC has received UI (Unnumbered Information) order in the sublayer, request LLC transmits data to application layer in the sublayer, application layer receives a DL_UNITDATA.indcation primitive that comprises LSDU (LLCService Data Unit), LLC receives the sublayer DL_UNITDATA.request interface primitive of self-application layer, notice LLC sublayer is transmitted the UI order from application layer and is sent request, and LLC is to the media access control sublayer Data transmission in request;

For the LLC3 type, LLC receives the sublayer from the MAC.indication of media access control sublayer interface primitive, notice LLC sublayer receives an ACn (Acknowledged Command/Response) order and sends corresponding ACn response, indication LLC transmits ACK (Acknowledge) or REPLY type primitive to application layer in the sublayer, application layer receives a DL_DATA_ACK.indication primitive that comprises LPDU (LLC Protocol Data Unit), LLC receives the sublayer DL_REPLY_UPDATE.request interface primitive of self-application layer, notice LLC upgrades inner reply data in the sublayer, and indication LLC upgrades successfully the still information of failure to the application layer transmission in the sublayer.

Described request LLC is a MAC.req primitive that comprises UI order PDU (ProtocolData Unit) to the media access control sublayer Data transmission.

The LLC1 type link controlling packet of described logic link control state machine contains four kinds of states: idle condition 0, LLC1 type command accepting state 1, LLC1 type command transmit status 8, LLC1 type command send done state 9, the LLC layer is received described interface primitive, state machine state transfers the order accepting state to by the free time, return idle condition then, send request when transmit the UI order from application layer, state machine state transfers LLC1 order transmit status to by Idle state, go to the LLC1 order then and send done state, go back to idle condition again.

The LLC3 type link of described state machine comprises nine kinds of states: the accepting state 2 of idle condition 0, LLC3 type command, ACK type command indicating status 3, REPLY type command indicating status 4, LLC3 type command reception done state 5, LLC3 response transmit status 6, LLC3 response send done state 7, the LLC3 module is upgraded its inner reply data state a, Data Update done state b;

1) received non-repetitive ACn order when the LLC sublayer, state machine is transferred to the accepting state 2 of LLC3 type command by the state free time 0, if the current described LPDU that receives effectively, the 4th bit P of non-NULL and LPDU control domain is 0, state machine goes to ACK type command indicating status 3 by the accepting state 2 of LLC3 type command, goes to the LLC3 type command more successively and receives done state 5, LLC3 response transmit status 6, LLC3 response transmission done state 7, idle condition 0; If the current described LPDU that receives is effective, non-NULL and P bit are 1, that is asked replys non-availability, and then state machine goes to REPLY type command indicating status 4, LLC3 type command successively by the accepting state 2 of LLC3 type command and receives done state 5, LLC3 response transmit status 6, LLC3 response and send done state 7, idle condition 0;

2) receive the renewal data-signal of application layer when the LLC layer, state machine is transferred to by the free time and upgrades reply data state a, after receiving the renewal ED signal of application layer, goes to Data Update done state b, gets back to idle condition 0 at last;

3) upgrade when the LLC layer data, and the LSDU non-NULL that receives, and the 4th bit P of LSDU control domain is 1, state machine by idle condition receive by the indication of reception, ACK type command, the order of order finish, response sends, response sends and finishes and the order of idle condition is changed;

4) replied LSDU and can get when what the LLC layer asked, and be said process 3) afterwards iterated command, state machine receives done state 5 by idle condition 0 by order accepting state 2, order, and response transmit status 6, response send the order of done state 7 and idle condition 0 and change successively; For the ACn order of retransmitting, no matter why the 4th bit P of the control domain of order PDU is worth, state can not go to the indication of ACK type command.

The present invention is according to GB 20851.2-2007 and adopt special logic to realize the LLC sublayer, this method for designing " is made to measure " domestic ETC system onboard unit, from the standard to hardware, all belong to a kind of practice of independent development, core technology to raising China ETC system-specific chip is most important, the inventive method produces such technique effect: the integrated level height of circuit, circuit power consumption is low.

Description of drawings

Fig. 1 is the state transition graph of state machine.

Fig. 2 is the simulation waveform of LLC1 type logical links.

Fig. 3 is the simulation waveform of LLC3 type logical links.

Embodiment

Contrast Fig. 1 (a), in up link, the state transition graph of board units logic link control state machine LLC1 type as shown, it comprises 4 states, and the order accepting state 1 of idle condition 0, LLC1 type, LLC1 type command transmit status 8 and LLC1 type command send done state 9.When the LLC layer is received MAC.indication primitive, if the LLC1 order receives, then notification type 1 module has been received UI order PDU, and state transfers the LLC1 order to by Idle state and receives, and the notice application layer, receive a DL_UNITDATA.indcation primitive that comprises LSDU.When DL_UNITDATA.request primitive is received in the LLC sublayer, then notification type 1 module transmits a UI order from application layer and sends request.State transfers the LLC1 order to by Idle state and sends, and go to the LLC1 order then and send end, and request LLC sublayer comprises the MAC.req primitive of UI order PDU to one of media access control sublayer transmission.

In up link, the state transition graph of LLC3 comprises 9 states, 0: the free time shown in Fig. 1 (b), the reception of 2:LLC3 type command, the indication of 3:ACK type command, the indication of 4:REPLY type command, the 5:LLC3 type command receives and finishes, 6:LLC3 responds transmission, the 7:LLC3 response sends and finishes, and the a:LLC3 module is upgraded its inner reply data, b: Data Update finishes.

(1) for non-repetitive ACn order, when the LLC layer is received MAC.indication primitive, if the LLC3 order receives, then notification type 3 modules have been received ACn order PDU, state machine transfers state 2 to by state 0, if the current LPDU that receives effectively, non-NULL and P be 0, this LSDU will pass to application layer by DL_DATA_ACK.indication so, and state machine goes to state 3 by state 2, go to state 5 more successively, state 6, state 7, state 0.If the current LPDU that receives is effective, non-NULL and P bit are 1, and that is asked replys non-availability, and then received LPDU will pass to application layer in DL-REPLY.indication primitive, and application layer is provided with update signal.State machine goes to state 4 successively by state 2, state 5, state 6, state 7, state 0.

(2) when the LLC layer is received the renewal data-signal rply_updt_req=1 of application layer, state machine goes to state a by state 0, when the LLC layer is received the renewal ED signal app_updt_end=1 of application layer, go to state b, application layer is given to application layer output DL_REPLY_UPDATE_STATUS.indication primitive in the LLC sublayer, with the data cell preparation request corresponding with it before the indication is success or failure, gets back to state 0 at last.

(3) upgrade when the LLC layer data, that is promptly asked replys LSDU and can get, and the LSDU non-NULL that receives, then received LSDU will have DL_DATA_ACK.indication primitive to pass to application layer, and state machine is by state 0, go to state 2 successively, state 3, state 5, state 6, state 7, state 0.

(4) replied LSDU and can get when what the LLC layer asked, and be iterated command after the process 3, according to relevant M signal is set, state machine goes to state 2 successively by state 0, state 5, state 6, state 7, state 0.This process only wishes that data pass to source LLC from purpose LLC, and information field that can order PDU be put sky.

(5) for the ACn order of retransmitting, no matter why the P among the order PDU is worth, can not send DL_DATA_ACK.indication primitive, if receive a LSDU in order PDU, will be dropped, the state variable of response remains unchanged.Except above situation, the LLC process when receiving iterated command PDU is identical with the LLC process that receives non-repeating transmission PDU.

The present invention analyzes according to the state of LLC, adopts hardware description language to realize the function of LLC sublayer, overcomes at present and realizes that with microcontroller the existing power consumption of controlling links is big, the not high defective of integrated level.

Simulation result of the present invention is shown in Fig. 2,3.Fig. 2 is the simulation waveform of LLC1, and Fig. 3 is the simulation waveform of LLC3.

Fig. 2 is the simulation waveform of LLC1.M_lpdu_c[7:0 in the waveform] be the PDU control domain of media access control sublayer, mac_ind is the indication that media access control sublayer transmits, unitdata_ind is a UI type command indication of passing to application layer, unitdata_req is the UI type command request primitive that application layer is passed to the LLC layer, llc_state[3:0] be the state machine of LLC sublayer, mac_req is the data, services primitive that media access control sublayer is passed in the LLC sublayer, l_lpdu_c[7:0] be the control domain of LLC sublayer.

According to the Bit Allocation in Discrete of Class1 operational order control domain, the control domain that media access control sublayer PDU is set is 8 ' h03, and coherent signal is set, when mac_ind=1, state machine transfers state 1 to by state 0, and output unitdata_ind=1, the notice application layer is received the UI order, returns state 0 at last; When unitdata_req=1, state machine goes to state 8 successively by state 0, and state 9, and output mac_req=1 promptly comprise the MAC.req primitive that UI orders PDU to one of media access control sublayer transmission.

Fig. 3 is the simulation waveform of LLC3.Rply_updt_req is the data to be transferred renewal primitive that application layer is passed to the LLC sublayer in the waveform, app_updt_end is the Data Update end signal that application layer is passed to the LLC sublayer, rply_updtst_ind passes to application layer data update mode primitive for the LLC sublayer, lsdu_updt_f is the Data Update marking signal, l_lpdu_f is that the LPDU of LLC sublayer exists sign, reply_ind is the exchanges data primitive that LLC passes to application layer, and ack_ind is the data transmission primitive that LLC passes to application layer.L_lpdu_c[7:0] be the LPDU control domain of LLC sublayer, l_lpdu_st[7:0] be the LPDU status field of LLC sublayer.

According to the Bit Allocation in Discrete of type 3 operational order control domains, the control domain that media access control sublayer PDU is set is 8 ' h77, and coherent signal is set, when mac_ind=1, state machine transfers state 2 to by state 0, because the LPDU non-availability, be the updating mark lsdu_updt_f=0 of service data unit, state machine goes to state 4, state 5, state 6 more successively, state 7, state 0, and when state 4, export reply_ind=1, the notice application layer is new data more.When upgrading data-signal rply_updt_req=1, application layer is new data more, and state machine goes to state a by state 0.When receiving renewal end signal app_updt_end=1, state machine goes to state b successively by state a, state 0, and when state b, export rply_updtst_ind=1, the notice application layer data upgrades successfully.When mac_ind=1, state machine transfers state 2 to by state 0 because LPDU can get, i.e. lsdu_updt_f=1, state machine goes to state 3 more successively, state 5, state 6, state 7, state 0, and when state 3 output ack_ind=1.When mac_ind=1, state machine transfers state 2 to by state 0, because the intermediate output signal l_lpdu_f=1 that is provided with, state machine goes to state 5, state 6, state 7, state 0 more successively.The control domain l_lpdu_c[7:0 of response pdus of output] and status field l_lpdu_st[7:0] the requirement of protocol compliant as a result.

Claims (4)

1. logical link control method based on LLC sub layer of on board unit of Chinese standard ETC system, in up link, the logic link control state machine of described board units comprises two types of LLC1 and LLC3, it is characterized in that:

For the LLC1 type, LLC receives the sublayer from the MAC.indication of media access control sublayer interface primitive, notice LLC has received the UI order in the sublayer, request LLC transmits data to application layer in the sublayer, application layer receives a DL_UNITDATA.indcation primitive that comprises LSDU, LLC receives the sublayer DL_UNITDATA.request interface primitive of self-application layer, and notice LLC sublayer is transmitted the UI order from application layer and sent request, and LLC is to the media access control sublayer Data transmission in request;

For the LLC3 type, LLC receives the sublayer from the MAC.indication of media access control sublayer interface primitive, notice LLC sublayer receives an ACn order and sends corresponding ACn response, indication LLC transmits ACK or REPLY categorical data to application layer in the sublayer, application layer receives a DL_DATA_ACK.indication primitive that comprises LPDU, LLC receives the sublayer DL_REPLY_UPDATE.request interface primitive of self-application layer, notice LLC upgrades inner reply data in the sublayer, and indication LLC upgrades successfully the still information of failure to the application layer transmission in the sublayer.

2. a kind of logical link control method based on LLC sub layer of on board unit of Chinese standard ETC system according to claim 1 is characterized in that described request LLC is a MAC.req primitive that comprises UI order PDU to the media access control sublayer Data transmission.

3. a kind of logical link control method according to claim 2 based on LLC sub layer of on board unit of Chinese standard ETC system, the LLC1 type link controlling packet that it is characterized in that described logic link control state machine contains four kinds of states: idle condition 0, LLC1 type command accepting state 1, LLC1 type command transmit status 8, the LLC1 type command sends done state 9, the LLC layer is received described interface primitive, state machine state transfers order accepting state 1 to by idle 0, return idle condition 0 then, send request when transmit the UI order from application layer, state machine state transfers LLC1 order transmit status 8 to by Idle state, go to the LLC1 order then and send done state 9, go back to idle condition 0 again.

4. a kind of logical link control method based on LLC sub layer of on board unit of Chinese standard ETC system according to claim 2 is characterized in that the LLC3 type link of described logic link control state machine comprises nine kinds of states: the accepting state 2 of idle condition 0, LLC3 type command, ACK type command indicating status 3, REPLY type command indicating status 4, LLC3 type command reception done state 5, LLC3 response transmit status 6, LLC3 response send done state 7, the LLC3 module is upgraded its inner reply data state a and Data Update done state b;

1) received non-repetitive ACn order when the LLC sublayer, state machine is transferred to the accepting state 2 of LLC3 type command by the state free time 0, if the current described LPDU that receives effectively, the 4th bit P of non-NULL and LPDU control domain is 0, state machine goes to ACK type command indicating status 3 by the accepting state 2 of LLC3 type command, goes to the LLC3 type command more successively and receives done state 5, LLC3 response transmit status 6, LLC3 response transmission done state 7 and idle condition 0; If the current described LPDU that receives is effective, non-NULL and described P are 1, that is asked replys non-availability, and then state machine goes to REPLY type command indicating status 4, LLC3 type command successively by the accepting state 2 of LLC3 type command and receives done state 5, LLC3 response transmit status 6, LLC3 response and send done state 7 and idle condition 0;

2) receive the renewal data-signal of application layer when the LLC layer, state machine is transferred to by idle condition 0 and upgrades reply data state a, after receiving the renewal ED signal of application layer, goes to Data Update done state b, gets back to idle condition 0 at last;

3) upgrade when the LLC layer data, and the LSDU non-NULL that receives, and P is 1, state machine by idle condition receive by reception, the indication of ACK type command, the order of order finish, response sends, response sends and finishes and the order of idle condition is changed;

4) replied LSDU and can get when what the LLC layer asked, and be said process 3) afterwards iterated command, state machine receives done state 5 by idle condition 0 by order accepting state 2, order, and response transmit status 6, response send the order of done state 7 and idle condition 0 and change successively; For the ACn order of retransmitting, no matter why the 4th bit P of the control domain of order PDU is worth, state can not go to the indication of ACK type command.

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