CSMA/CN: carrier sense multiple access with collision notification
CSMA/CN: carrier sense multiple access with collision notification
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DOI：
10.1145/1859995.1859999
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发表时间：
2010-09
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影响因子：
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通讯作者：
Souvik Sen;Romit Roy Choudhury;Srihari Nelakuditi
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文献类型：
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作者：
Souvik Sen;Romit Roy Choudhury;Srihari Nelakuditi
无线发射机仅在完成整个传输后才能获知分组丢失、推断冲突。如果发送器可以及早检测到冲突(例如有线网络中的CSMA/CD)，它可以立即中止传输，从而释放信道进行有用的通信。在无线网络中实现CSMA/CD主要有两个障碍。首先，无线发射机不能同时发送和监听冲突。其次，发送器周围的任何信道活动可能不是接收器处冲突的指示器。本文尝试用一种称为CSMA/CN(冲突通知)的方案来近似无线网络中的CSMA/CD。在CSMA/CN下，接收方使用物理层信息来检测冲突，并立即通知发送方。冲突通知由在与数据相同的通道上发送的唯一签名组成。发送器使用收听者天线并执行特征相关来识别该通知。一旦识别，发射机立即中止传输。我们证明，即使在来自发射天线的强自干扰存在的情况下，通知签名也可以在收听者天线处被可靠地检测到。10个USRP/GNURadios原型试验台验证了CSMA/CN的可行性和有效性
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 notification. Once discerned, the transmitter immediately aborts transmission. We show that the notification signature can be reliably detected at the listener antenna, even in the presence of a strong self-interference from the transmit antenna. A prototype testbed of 10 USRP/GNURadios demonstrates the feasibility and effectiveness of CSMA/CN