802.11p v.s. V2V v.s. ADAS

V2V是繼ADAS之後的新一代車聯網技術，講求車輛之間要能即時、自動地傳遞訊息，因此需要比現在的車聯網技術擁有更低的延遲性(Latency)；而802.11p就擁有這樣的特性，其延遲性僅有5毫秒。江敏楠進一步舉例，V2V就是要讓車輛早駕駛一步處理緊急狀況，例如當前方發生事故時或前面車輛緊急煞車，後方車輛須在極短的時間內接收到訊息，並立即停下來。

IEEE 802.11p is an approved amendment to the IEEE 802.11 standard to add wireless access in vehicular environments (WAVE), a vehicular communication system. It defines enhancements to 802.11 (the basis of products marketed as Wi-Fi) required to support Intelligent Transportation Systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz). IEEE 1609 is a higher layer standard based on the IEEE 802.11p.^[1]

IEEE 802.11p standard uses channels of 10MHz bandwidth in the 5.9GHz band (5.850-5.925 GHz). This is half the bandwidth, or double the transmission time for a specific data symbol, as used in 802.11a.


802.11p was considered for dedicated short-range communications (DSRC), a U.S. Department of Transportation project based on the Communications, Air-interface, Long and Medium range (CALM) architecture of the International Organization for Standardization for vehicle-based communication networks, particularly for applications such as toll collection, vehicle safety services, and commerce transactions via cars. The ultimate vision was a nationwide network that enables communications between vehicles and roadside access points or other vehicles