Routing Metric Based on Available Transmission Time for Wireless Mesh Networks

Routing metric is critical for performance of wireless mesh networks (WMN). Without considering back-off scheme of IEEE802.11 in Mac layer, expected transmission count (ETX) and expected transmission time (ETT) can not evaluate the average transmission time accurately. A new available transmission time routing metric is proposed based on IEEE 802.11 DCF. We also extend OLSR protocol on Linux platform, and compare ATT with ETX and ETT. The obtained results show that the ATT metric has the lowest packet loss rate and the lowest jitter rate among the analyzed metrics, because it concerns available link bandwidth and also takes physical transmission rates into account.