Advances in Automobile Engineering

Transcription

1 nadvances in Automobile E gineeing ISSN: Advances in Automobile Engineeing Kabi, 2012, 1:3 DOI: / Reseach Aticle Open Access Netwok Achitectue of a Moden Automotive Infotainment System Mashud Kabi* Design & Evaluation Lab, Panasonic Automotive System Euope, Robet-Bosch-Stasse 27, Langen, Gemany Abstact Due to the advancement in technology and consume electonics, automotive infotainment system is gowing apidly. Moe and moe new technologies and devices ae integated into the system. All the infotainment electonic contol units (ECUs) ae netwoked in the automotive platfom. Theefoe, it has always been a challenging topic fo eseaches and enginees to find an appopiate netwok achitectue which can adjust with the newly added ECUs and use demands. Until the last few yeas, automotive devices wee integated using olle Aea Netwok (CAN) technology. Due to the slow speed of data tansfe in olle Aea Netwok (CAN) (geneally up to few hunded Kilo Bytes pe second), a new technology named as MOST (Media Oiented System Tanspot) was intoduced. Hee, the data is tansfeed optically. Fo the last few yeas, moe and moe applications including Navigation system, Multi Media Playe, ipod, SD Cad, USB Memoy, Instument Cluste, Digital Tune sand Telephony have been integated into the MOST system. Data tansfe ate of up to 150 MB its pe second is ealizable using MOST. In this pape, MOST netwok achitectue which is the babone of moden infotainment platfom, netwok management potocols and elated devices ae pesented. Keywods: Automotive multimedia; Netwok; Achitectue; Communication laye Intoduction This pape pesents at fist an oveview of automotive infotainment featues to get a geneal undestanding of the system. Then infotainment netwok system with its nodes is discussed. As MOST is the main focus of the moden netwok achitectue concept, its components along with thei applications ae explained. Then MOST communication laye model based on classical OSI laye model is explained. Infotainment and Multimedia Featues To get a good undestanding of infotainment and multimedia system, it is necessay to know the featues in this aea. The section descibes the featues based on the types of application modes. All featues that the Infotainment and Multimedia system povides ae ealized by softwae components which ae deployed on ca devices and sevice centes. The featues can be gouped as follows: i. Entetainment sevices ( e.g. Radio, DVD, TV, Digital Radio (DAB), Rea Seat Entetainment, SDARS,SIRIUS, ipod, USB Memoy, SD Cad etc.) ii. Infomation sevices (e.g. Navigation including oute planning, dynamic oute guiding and tavel guidance) iii. Telecommunication sevices (e.g. voice telephony, SMS, , Remote Climate ol and Remote Doo Lo/Unlo, Bowse List) iv. Advanced use of ca functions (e.g. adjustment of extenal mios, climate contol, seat adjustment) v. Safety sevices (e.g. Emegency-call, Ca Taing) vi. System administation sevices (e.g. esouce management, channel allocation/deallocation, softwae download and engineeing mode). Infotainment Netwok System The infotainment system can be chaacteized as a distibuted, heteogeneous hadwae/softwae system, which povides functionalities and sevices to the custome via the inteaction of seveal devices. The hadwae components ae inteconnected by standadized ca netwoks (e.g. MOST, CAN bus) [1] and by wieless communication channels (e.g. Bluetooth). An oveview of the main components of Infotainment & Multimedia in a passenge ca is pesented below: Head unit Head Unit (HU) is egaded as the maste in the netwok. It contains one o moe CPUs. The HU has atleast one CPU fo eal time communication puposes (e.g. infotainment gate way) and at least one CPU fo the use inteface to inteact with infotainment applications (Main CPU). Infotainment & multimedia gateway Infotainment & Multimedia Gateway contains at least a CPU (Gateway CPU) fo eal time communication with othe peipheal components like memoy, CAN tansceives, MOST tansceive and othe components. The gateway CPU is connected to the main CPU with an intenal bus. As the main CPU is not connected diectly to the MOST command/contol channel and the CAN netwok [2], all messages fom the Main CPU to the outside wold ae sent and eceived ove the gateway CPU. Figue 1 shows that a HU must contain a main CPU and a Gateway CPU. Can netwok One of the main tasks of HU is to contol the basic vehicle functions. The gateway is not connected diectly to the contol units of vehicle functions. It is connected to the Cental Gateway (it manages the othe CAN netwoks in the vehicle) by a high speed CAN (Babone CAN). *Coesponding autho: Mashud Kabi, Design & Evaluation Lab, Panasonic Automotive System Euope, Robet-Bosch-Stasse 27, Langen, Gemany, mashud.kabi@ext.eu.panasonic.com Received Apil 21, 2012; Accepted July 26, 2012; Published July 30, 2012 Citation: Kabi M (2012) Netwok Achitectue of a Moden Automotive Infotainment System. 1:101. doi: / Copyight: 2012 Kabi M. This is an open-access aticle distibuted unde the tems of the Ceative Commons Attibution License, which pemits unesticted use, distibution, and epoduction in any medium, povided the oiginal autho and souce ae cedited.

2 Citation: Kabi M (2012) Netwok Achitectue of a Moden Automotive Infotainment System. 1:101. doi: / Page 2 of 5 Main CPU The HU is connected with the HUCAN. Some contol devices on the HU-CAN communicate only with the HU. Thee ae some othe devices fo which the messages ae only outed though the gateway fom the HU-CAN to the Babone-CAN and vice vesa. The CAN messages and signals ae specified in some matices. Most netwok and potocols HU Gateway CPU Figue 1: HU Pocessos. MOST (Media Oiented System Tanspot) is a high speed netwok, which connects infotainment components with the cental unit (HU) though the gateway [3]. It is a closed-loop netwok. The gateway must be able to handle command/contol data of MOST [4]. A MOST device is a physical entity which may include multiple functional components. These components ae called Function Blos (). Fo example, the MOST device Rea Seat Entetainment (RSE) consists of seveal s such as MultiMedia Playe, HeadPhone Amplifie, and Auxiliay Input etc. An is identified with special ID names such as ID. In a MOST system, a specific may exist moe than one time. To avoid any conflict among them, each is assigned with an instance identifie efeed to as InstID. The combination of ID and InstID makes an entity unique fo addessing. This is temed as functional addess. An consists of many functions, like mute, volume, allocate etc in MOST HeadPhoneAmplifie. In ode to distinguish between diffeent functions, evey function has its own Identity which is called FktID. With the help of a function, cetain opeations ae pefomed on espective popeties o methods. The kind of opeation is expessed by OP TYPE, e.g. Stat, Get, StatResult etc. Each OP TYPE may contain seveal paametes. To pefom a specific opeation on a specific function blo, a message of the following fomat is used: <ID.InstID.FktID.OpType (Data)> To ealize an application of a MOST device, the above stuctue is implemented accoding to the detailed guidelines in a function catalog. A function catalog lists all the s, instances, functions, OP TYPEs and paametes. Fom the MOST application point of view, a MOST device can be said to be eo fee if the complete function catalog functions coectly. Theefoe, it is of pime impotance to test the function catalog thooughly. This test is also called a Static Function Test, as a fixed set of functions ae tested hee. The test of the function catalog stats by eading the Device Identity such as hadwae/softwae/boot loade vesion fom the MOST devices. Then all the implemented and non-implemented IDs (0x00 0xFF) ae veified. Non-implemented IDs ae tested to fulfill negative equiements whee an appopiate eo message is expected. Each existing in a MOST device has cetain InstID(s). InstIDs ae veified by keeping in mind the assigned instances fo an, wild-cads (nomally InstID 0x01n and 0xFF ae defined as wild-cads) and all incoect instances. The FktIDs ae veified fo positive and negative test cases to ensue that poject specific FktIDs exist, and the othe FktIDs do not exist in the. In addition to the poject specific function catalog, a geneal function catalog obtained fom MOST Coopeation is used to decide which functions should be taken to test negative cases. Usually the unused functions in the geneal function catalog ae consideed fo negative tests. The same test stategy is also applied fo OP TYPE veification. Automotive infotainment system consists of seveal ECUs (Electical ol Units). Some defined potocols should be developed to manage the connected devices. These sets of potocols can be temed as Netwok Management. Netwok management tasks include statup, shutdown, wakeup, powe moding, addessing, allocation, deallocation, audio management etc. Statup behavio manages the by-pass close/open, timely esponse fo NetBlo queies, egistation of s, configuation contol, esouce de-allocation etc. NetBlo is a special function blo, which povides functions elated to the entie device. Each MOST device must contain this. Shutdown behavios deal with the pope saving of cuent settings, communication ability, attachment of s in the cental egisty, light off behavio, wheeas wakeup behavios set the guidelines fo light tavel time fom input to output in ECUs, lo/ unlo, light off etc. Powe moding behavios deal with the device chaacteistics in unde voltage and ove voltage. It also defines the consumption of powe duing nomal mode and sleep mode. Netwok management addess ingensues the coect sending and eceiving of messages in the system. Allocation, de-allocation and audio management ae the aeas whee souces, sinks, esouce management ae handled. The HU contains the MOST s and contolles, which ae necessay fo contolling the netwok behavios of the HU. Below is a list of logical intefaces fo some common devices: - Head Unit (though MOST) - Speech ol System (though MOST) - Mobile Phone (cadle o Bluetooth) - Instument Cluste (though Head Unit) - Amplifie/Sound (though MOST) Most Netwok Achitectue A MOST device contains a eceive and a sende. The input of a most device is optical light and the output is also optical light. The light is modulated inside the device to get o send the necessay infomation. It is essential that a MOST device is stable duing opeation. It means thee must not be any light off, unlo without any specified and pope easons. A light off o an unlo in a single device would make the whole system unstable. A typical MOST ing contains the following components which is depicted in Figue 2. The components ae descibed below: i. Amplifie: Amplifie is a mandatoy ECU in MOST infotainment system. This woks as a sink of audio data. ii. Telephony: Telephony contains a mobile Inteface. This is an

3 Citation: Kabi M (2012) Netwok Achitectue of a Moden Automotive Infotainment System. 1:101. doi: / Page 3 of 5 D V Ra dio Amplifie Telep hony HU M OS T Na vi Gat ewa TVT une Digital Radio Rea Seat Entetain ment Displa y optional device in a MOST ing. The inteface connects the Bluetoothenabled mobile phone and othe MOST components. iii. Rea Seat Entetainment: Rea Seat Entetainment (RSE) is an optional device. It may contain MultiMedia Playe, HeadPhone Amplifie, and Auxiliay Input. iv. TV Tune: TV Tune povides eception fo video and audio. This is an optional component in a MOST ing. A TV Tune can have vaiants of digital, analog o hybid (analog/digital). The video output is sent to display and audio is sent to amplifie. v. Gateway: This is a mandatoy component in MOST infotainment system. Gateway is the inteface between MOST and CAN netwok. MOST commands ae tanslated into CAN commands wheneve any command is sent fom MOST to CAN. Similaly, CAN commands ae tanslated into MOST commands if the taget of the command is an element of the MOST netwok. vi. Radio: Radio is a mandatoy element of MOST. It can be an analog o digital tune. This is a souce fo audio data which is tansfeed to an audio amplifie. Softwae Download and Use olle (UC) ae two commonly used tems which ae biefly descibed below: CAN CAN Use olle Cental Gate Way Figue 2: Infotainment and Multimeida Achitectue. Softwae download Softwae download means flashing softwae into Infotainment & Multimedia devices. Poviding an inteface to download softwae into Infotainment & Multimedia devices pemits the sepaation, to a cetain degee, of the hadwae development cycle fom the softwae development cycle and adds new (updated o additional) functionalities without changing the hadwae. Use contolle (uc) The use contol (UC) is a mechatonic inteface between the head unit and the use. Use commands can be povided though the movement of the buttons and pessue-opeated otay actuato. The commands ae tansmitted to the HU via CAN-bus. Communication Laye Model of Most Netwok This section discusses the Infotainment and Multimedia layeing in an automotive system. At fist a bief oveview of OSI communication laye model is discussed. Then ou infotainment and multimedia layeing is pesented. In the OSI communication laye model, thee ae seven layes which is depicted in Figue 3. The Physical Laye descibes the physical popeties of the vaious communications media, electical popeties and intepetation of the exchanged signals. Fo example, this laye defines the size of Ethenet coaxial cable. The Data Link Laye defines the logical oganization of data bits tansmitted on a paticula medium. Fo example, this laye descibes the faming and addessing of Ethenet paets. The Netwok Laye explains how a seies of exchanges ove vaious data links can delive data between any two nodes in a netwok. Fo example, defining the addessing and outing stuctue of the Intenet is one of the main tasks handled by this laye. The Tanspot Laye descibes the quality and natue of the data delivey. Fo example, this laye defines if and how etansmissions will be used to ensue data delivey. The Session Laye descibes the oganization of data sequences that ae lage than the paets handled by lowe layes. The tasks of this laye include how equest and eply paets ae paied in a emote pocedue call. The Pesentation Laye descibes the syntax of data being tansfeed. Fo example, this laye descibes how floating-point numbes can be exchanged between hosts with diffeent math fomats. The Application Laye descibes how eal wok actually gets done. Application Laye Pesentation Laye Session Laye Tanspot Laye Netwok Laye Data Link Laye Physical Laye Figue 3: Communication Laye Model.

4 Citation: Kabi M (2012) Netwok Achitectue of a Moden Automotive Infotainment System. 1:101. doi: / Page 4 of 5 Navi olle Radi o olle Opeating System Hadwae HMI NMENT SYSTEM CD olle System Infastuctue Call olle MOST NetSevices MOST Hadwae Figue 4: MOST Communication Layes. As fo example, this laye implements file system opeations. Based on the above discussion egading the OSI communication laye model, a geneal laye model fo Infotainment & Multimedia system based on MOST is pesented hee. MOST communication netwok is layeed into thee pats: i. Physical laye ii. Netwok laye iii. Application laye. Figue 4 shows the MOST communication laye model. i. Physical Laye Seveal Infotainment and Multimedia hadwae platfoms ae distibuted ove the ca and in the infastuctue. The devices integated in the vehicle ae inte connected by MOST and CAN buses. These in S l a v e Co nt oll e App licat ion Lay e Ne tw ok La ye Phy sica l Lay e ca plat foms constitute the physical laye. The physical laye deals with the following: Tansmitte Receive Device Connecto Cabling Powe Budgeting Signal Timing Diagnostic Requiements Component Specification System Desciption Coodination ii. Netwok Laye The communication stas and MOST/CAN netwok management functions as a whole constitute the netwok laye. The netwok laye deals with the following: Net Sevices - Communication between devices is ealized in the majoity of cases via the MOST NetSevices. Thee is also a Gateway to communicate with CAN devices. Fo futhe communication puposes via othe netwoks additional potocol stas, e.g. WAP, ae implemented. Tanspot Potocols - Tanspot potocols deal with contol and segmented data communication ove the contol channel, the amount of data fo such a connection, MOST High Potocol as tanspot potection fo steaming and application data on tanspot laye level. Bounday - The bounday fo the distibution of synchonous and asynchonous channels is to set to a fixed numbe. MOST netwok management level - MOST Addess Handling, Instance ID Handling and Naming. Netwok Maste - Afte the MOST netwok on a basic level is eady fo communication (NetOn), the netwok maste ches if it has a valid logical node addess. It also manages the following behavios of a device: IP Addess Handling MAC Addess Handling Low Voltage Device Behavio iii. Application Laye The application laye is at the top of the system laye. It consists of the system infastuctue including infastuctue softwae components (e.g. Resouce Management - poviding functionality) geneally equied in application components o equied to ensue that the system as a whole functions popely. It consists of geneal equiements, achitectual equiements, and a detailed specification of functionalities and intefaces. The application laye deals with the followings: Application components (contolles and slaves) focus on the functionalities and logics equied fo a specific application.

5 Citation: Kabi M (2012) Netwok Achitectue of a Moden Automotive Infotainment System. 1:101. doi: / Page 5 of 5 The MMI famewok is esponsible fo the handling of inteaction between the infotainment and multimedia system and its uses. Conclusion In this pape I have descibed the featues of a moden automotive infotainment and multimedia system. Existing netwok concept is not capable of handling and adopting the new electonic devices which equie high data tansfe ate. Theefoe, existing CAN is eplaced by MOST. MOST is elatively a new aea in automotive secto. This is a ing topology. A moden MOST netwok achitectue has been pesented hee. Based on the classical OSI communication laye, a thee laye model fo automotive infotainment netwok has been discussed. Refeences 1. Bell J (2002) Netwok potocols used in the automotive industy. 2. Rusek A, Oakley B, Stevens D, Hillie L (2009) Compute Modeling of CAN Automotive BusTansceives. 3. Schöpp H (2001) Pactical Aspects of Implementing MOST Systems and Devices MOST Devices. 4. OASIS, SMSC (2009) Automotive Infotainment Solutions.