伟世通公司的V2V(车车通信)开发模块帮助工程师解决安全等难题。

最近美国国家公路交通安全管理局（NHTSA）批准了车车通信(V2V)/车路通信对基础设施(V2I) (简称V2X)通讯技术研究之后，主流媒体就开始大肆宣传。但是他们没有注意到，在V2X真正起作用之前还需要克服很多技术性的困难。

美国国家公路交通安全管理局并没有给整车厂是否决定把V2X应用到车辆上设立任何时间表。其中一个需要克服的技术难题就是安全问题，正因如此何时应用这项技术一直没有定论。另一个摆在面前的难题就是要有足够多车辆运用该技术才能看到它真正的优势，同时对云端技术也存在一定的挑战。

大多数整车厂和一级供应商都将它作为一项远期技术正在持续观望中。而他们却都在开发自动驾驶技术，并把V2X作为“第二个传感器”，相较于车载传感器，V2X能帮助控制系统掌握更多的路况信息。比如前方不在视野内的大型卡车进行了紧急刹车，能够及时提醒驾驶员/控制系统作出反映。不过，V2X与任何形式自动化相结合都还为时尚早。

 “我们需要V2X来实现自动驾驶吗？不需要。”博世集团底盘系统控制事业部的自动化驾驶区域业务经理Kay Stepper谈到，“那它有用吗？有。一旦等到V2X成熟，我们当然会用。但是真正应用这一技术我们还需要花上很长时间。”

当政府部门在纠结展示时机的问题时，各公司已经在持续探索使用手机蜂窝网络连接，获取数据带来的好处，它能大致模仿V2X中专用短程通信（DSRC）技术。

沃尔沃汽车公司的高级技术主管Erik Coelingh说：“V2X确实是另一种传感器，但是我还是认为使用手机蜂窝网络、3G还有4G所获得的信息要比DSRC丰富。如果出现绕行或者车道关闭的情况，GPS就没有用了。这个时候就需要去云端查看实时路况信息。”

其他人则认为手机网络连接也许只是一种过渡技术，将最终与DSRC各承担不同相应的分工。

大陆汽车北美部内部电子解决方案主管Tejas Desai说：“V2X的一个基础就是车辆到云端数据的交流以及云端数据的匿名集合。这使得我们可以逐步分步骤的建立这个系统，在实现安全性和其他任何自动功能之前不需要建成全套基建设施。”

V2X的一大障碍就是如何向全套基础设施过渡，如果提供DSRC连接的汽车数量达不到一定比例，就很难收回安装信号收发器的成本。很多观察人员都认为，除非是监管机构表态，否则这项技术终会凋零。

QNX软件系统自动产品营销高级经理Andy Gryc指出：“如果政府不用强制措施，那么V2X就不会实现。如果只能跟自己小圈子里的车队对话，谁又会花那个钱在车上装这种系统呢？”

意法半导体公司ADAS（高级驾车辅助系统）营销经理Paolo Ruffino也同意投资V2X的顾虑，他说：“这项技术面对的主要威胁就是，没有能够吸引基建建商的商业模式，比如电信业，从某种程度上讲，也包括道路运营商。”

使这项技术迟滞不前的另一顾虑就是安全问题。汽车可以应用V2X提供的信息进行安全相关的操作时，控制器必须要搞清楚信息是来自真车或者路边信号台，而不是黑客。

美国天合汽车全球研发总监及安全集成团队主管Alois Seewald说道：“V2V的安全性极为关键。如果要用它获得安全信息，那就必须知道数据来源有保障。”

一些观察人员觉得，第一批V2X系统可以继续在上市以后逐步提高其安全性能，特别是可以先不用于自动化安全操作，比如刹车。早期系统可以只用来向驾驶员发出警报，驾驶员自己可以判断警报是否有误。不过如果V2X要用于主动安全系统，那么就必须拥有极为可靠的安全技术，而且还能根据不断变化的进行升级改进。

伟世通公司高级发展与知识产权副总监Brian Daugherty说：“如果V2X作为另一种传感器被集成到汽车的控制系统里，那么安全问题就更需要重视了。早期设备是否可以应对未来的不断的升级将是应用的关键，谁也不希望看到它们因为安全协议的修改而被淘汰掉。”

零配件市场方面的问题也让开发商的意见并不统一。有些开发商觉得零配件市场体系可以加速这种交流通信的应用并增加其数量与价值，而另一些则认为独立供应商不能做安全相关的技术。

Daugherty认为：“零配件市场体系会大大提高V2X的渗透率曲线，也会相应地使整个生态系统相对驾驶员的价值不断上升。零配件市场体系要为购买者带来价值，可以囊括从不带反馈信息的‘我在这里定位系统’，到带有显示器以及一系列警告系统的全套V2X系统。”

有些人认为，零配件市场体系大概只能用于基础通信。汽车制造商也不太可能允许未经授权的小盒子连接到车载网络中，担心这样会危及安全。

Seewald说：“对于是否允许未知物体连接到安全系统上这一问题，整车厂的保留意见非常强烈。他们可以向零配件商提供产品，但是却不太可能接受真正的零配件市场体系。零配件供应商还有一个问题就是，他们很难提供大量产品。”

业界和监管机构纠结着这些那些问题时，观察人员又指出，为V2X预留出5.9 GHz频段也许是非常重要的。美国联邦通信委员会（FCC）正在测试与非汽车小组共享这尚未使用的频段时所产生的影响及可能性。这一点可能会影响实时通信的能力，而实时通信对安全是极为重要的 。

Daugherty指出： “其他产业都非常希望共享这个专为V2X留出的5.9-GHz频段。如果不赶快行动，这种共享频段的行为就可能会对V2X产生负面影响。”

作者：Terry Costlow

isteon’s V2V development module helps engineers solve challenges such as security.

Mainstream media outlets heavily touted vehicle-to-vehicle/-infrastructure (referred to as V2X) communications after a recent NHTSA endorsement. Often overlooked are technical challenges that still must be overcome before V2X can make any real impact.

The U.S. NHTSA (National Highway Traffic Safety Administration) hasn’t set any timetable for determining whether or not it will make OEMs put V2X on vehicles. Security is one of the technical hurdles that’s slowing decisions about deployment. Getting enough vehicles on the road to bring any real benefit is another roadblock. There’s also a challenge from the cloud.

Most OEMs and Tier 1s are viewing it as a long-term technology. As they move towards autonomous driving, many developers see V2X as "another sensor" that can help control systems understand what’s going on at distances greater than onboard sensors can provide. It can also alert controllers that an unseen car in front of a large truck has slammed on its brakes. However, the combination of V2X with any form of autonomy won’t happen soon.

“Do we need V2X for autonomous driving? No,” said Kay Stepper, Regional Business Manager for Automated Driving at Robert Bosch Chassis Systems Control Division. “Will it help? Yes. Once V2X is in place, of course we’ll utilize it. But deployment will take a long time.”

While government agencies grapple with the timing of a rollout, companies continue to explore the benefits of using cellular links to collect data that loosely mimics the capabilities of the dedicated short range communications (DSRC) used for V2X.

“V2X is another sensor, but I believe there’s more information available in cellular, 3G, and 4G than you can get with DSRC,” said Erik Coelingh, Senior Technical Leader at Volvo Cars. “If there’s a detour or lane closure, GPS won’t help. You need to go to the cloud to a real-time network.”

Others contend that cellular links may be an interim technology that will eventually share a role with DSRC.

“One stepping stone for V2X is the introduction of vehicle-to-cloud data communication and the anonymous aggregation of this data in the cloud,” said Tejas Desai, Head of Interior Electronic Solutions at Continental Automotive North America. “This will allow for the systems to be built up over time instead of requiring full infrastructure to be in place before realizing benefits to safety or realizing any of the autonomous functionality.”

The transition to a full infrastructure is a major hurdle for V2X. Until a solid percentage of vehicles offer DSRC connectivity, it’s difficult to justify the cost of installing transceivers. Many observers feel the technology will languish unless regulators take a stand.

“Without a government mandate, V2X won’t happen,” said Andy Gryc, Senior Automotive Product Marketing Manager for QNX Software Systems. “Who will spend the money to put the technology into vehicles if they can only talk to your fleet?”

Paolo Ruffino, ADAS Marketing Manager at STMicroelectronics, echoed concerns about investing in a V2X rollout. “The main threat to this technology is the lack of a business model that could lure the infrastructure owners, such as telecom, and to some extent road, operators,” he said.

Security is another concern that’s slowing development. Before cars can used V2X input for safety-related actions, controllers must know that communications came from a real car or roadside beacon, not a hacker.

“Security on V2V is critical,” said Alois Seewald, Global R&D Director and head of TRW’s Safety Integration Team. “If you’re going to use it for safety information, you need to know you’re getting good data.”

Some observers feel that security can be improved after the first rollout of V2X systems, particularly if the inputs aren’t used for automated safety actions such as braking. Early systems will only be used to warn drivers, who can better determine whether they’re getting false alarms. But if V2X becomes part of active safety systems, it will have to have very solid security technologies that can be upgraded as threats change.

“Once V2X is integrated as another sensor into vehicle control systems, security will be even more important,” said Brian Daugherty, Visteon’s Associate Director of Advanced Development and Intellectual Property. “The ability to handle future upgrades will be a key deployment feature; you don’t want the early systems to become obsolete due to security protocol modifications.”

Aftermarkets are yet another issue that divides developers. Some view aftermarket systems as a viable way to speed up deployment and increase the volume and value of these communications. Others don’t feel that independent suppliers can play a role in safety-related technologies.

“Aftermarket systems will dramatically increase the V2X penetration curve and bring a corresponding increase in the value of the entire ecosystem to drivers,” Daugherty said. “Aftermarket systems will need to bring value to the purchaser and could range from ‘here-I-am systems’ with no feedback to full V2X systems with a display and a suite of warning algorithms.”

Others contend that aftermarket systems may be used only for basic communications. Automakers aren’t likely to let unauthorized boxes connect to in-vehicle networks that can impact safety.

“OEMs have strong reservations about letting an unknown entity have access to the safety system,” Seewald said. “OEMs may provide products for the aftermarket, but it’s unlikely that they will accept a true aftermarket system. Another issue for aftermarket suppliers is the difficulty of providing redundancy.”

While the industry and regulators grapple with these and other issues, observers note that it may be important to start using the 5.9-GHz bandwidth set aside for V2X. The U.S. FCC (Federal Communications Commission) is examining the impact of letting non-automotive groups share this currently unused spectrum. That could impact the ability to communicate in real time, which is critical for safety applications.

“There is a strong desire from other industries to share the 5.9-GHz spectrum that has been reserved exclusively for V2X,” Daugherty said. “If action isn’t taken quickly, spectrum sharing may lead to degraded V2X performance.”

Author：Terry Costlow