Stabilisation of the MAC function in the W-CDMA access interface

We present an evaluation of the OSSS (overload signal spread spectrum) protocol of P.E. Omiyi and T. O'Farrell (see Electronics Letters, vol.34, no.12, p.1201-2, 1998) when the backlogged load is estimated and used as a preventive mechanism to avoid overloading the channel (with the use of a transmission probability). We propose a method for the estimation of the backlogged load and show that the system stability is enhanced (with a bounded level of access delay) at offered loads not higher than 0.75 (normalised value). The throughput for traffic with 0 sec delay requirement reaches a value close to 0.7.