CSMA/CN: carrier sense multiple access with collision notification

A wireless transmitter learns of a packet loss, infers collision, only after completing the entire transmission. If the transmitter could detect the collision early (such as with CSMA/CD in wired networks), it could immediately abort its transmission, freeing the channel for useful communication. There are two main hurdles to realize CSMA/CD in wireless networks. First, a wireless transmitter cannot simultaneously transmit and listen for a collision. Second, any channel activity around the transmitter may not be an indicator of collision at the receiver. This paper attempts to approximate CSMA/CD in wireless networks with a scheme called CSMA/CN (collision notification). Under CSMA/CN, the receiver uses PHY layer information to detect a collision and immediately notifies the transmitter. The collision notification consists of a unique signature, sent on the same channel as the data. The transmitter employs a listener antenna and performs signature correlation to discern this notificat...

• Type: Conference
• Year: 2010
• Where: MOBICOM
• Authors: Souvik Sen, Romit Roy Choudhury, Srihari Nelakuditi
• Keywords: Collision, Communications, MOBICOM 2010, Transmitter, Wireless