Combining random backoff with a cross-layer tree algorithm for random access in IEEE 802.16

We investigate the potential for high throughput when combining random backoff schemes with a robust cross-layer tree algorithm (TA) for wireless random access. We first develop a BEB-SICTA/FS protocol which combines the binary exponential backoff (BEB) algorithm with a recently proposed SICTA/FS protocol. Saturation throughput analysis of BEB-SICTA/FS motivates the combined protocol herein because: 1) by using the practically feasible SICTA/FS to resolve collisions in a conventional BEB based protocol for wireless random access, we can achieve high throughput; and 2) BEB can sufficiently reduce the collision size and thus enhance the efficiency of SICTA/FS, since SICTA/FS is more efficient when the number of initially collided packets is small. Guided by our analysis, we further put forth a GBEB-SICTA/FS protocol which is capable of higher and more steadfast saturation throughput than BEB-SICTA/FS. Finally, we tailor our protocols for the IEEE 802.16 broadband wireless access (BWA) networks and test their performance through simulations.