Abstract:

In order to differentiate real-time traffic from best-effort traffic in multi-hop Ad hoc networks, a new differentiated medium access control (MAC) scheme, differentiated label-swiching distributed coordination function (DL-DCF) is proposed. Forwarding information is obtained by label in MAC layer and is piggybacked in Request-acknowledgement (RACK) frame. Clear to send (CTS) handshake of the downstream node was triggered by RACK that made the data frame transmit consecutively across multi-hop. The probability of performing consecutive transmission is calculated according to traffic type and occupied ratio of the higher layer data buffer in MAC layer that can realize service differentiation and avoid data buffer overload. Simulation shows that compared with 802.11 DCF , under high loads, DL-DCF can remarkably decrease the end-to-end delay and normalized control overhead, increase the throughput, and realize service differentiation.

Key words: medium access control scheme, differentiated label-swiching distributed coordination function, differentiated service, consecutive transmission, label switching