Collision-free operation in ad hoc carrier sense multiple access wireless networks

The CSMA/CA algorithm proposed in the IEEE 802.11 standard does not exclude collisions between transmitted packets. Regardless of whether RTS/CTS packets are used or not, these collisions do always have a more or less negative effect on system performance, especially at high loads. In this letter a method of avoiding collisions by using busy energy bursts is proposed. The algorithm used is based on the 802.11 standard and depends only on the assumption that each node can hear the transmissions of all other nodes. Collisions are avoided by transmitting short sequences of energy bursts without the need of any further communication between nodes contending for the use of the channel. The proposed method provides better average packet delays also as higher maximum system loads than conventional CSMA/CA. In addition to this, it renders the use of acknowledgment packets unnecessary.