Collision-minimizing CSMA and its applications to wireless sensor networks
Current anti-collision protocols for active RFID systems stem from the ISO-18000-7 standard, which selects Frame Slotted Aloha as the underlying medium access control protocol. However, these approaches neglect the possibility of using the listen-before-talk mechanism already available in active RFID tags. In a previous work, a CSMA (Carrier Sense Multiple Access) mechanism CSMA/MS (Multi-Stage) was proposed in order to substitute the anti-collision procedure in active tags. The key of this CSMA/MS is to concatenate various contention windows, where only winners contend in the next contention stage. With the same overall number of contention slots, the staging approach greatly improves performance if the window division is correctly selected. In this new work, this issue is investigated and suitable configurations, derived by means of numerical test, are provided.