DISTRIBUTED AUTONOMOUS WIRELESS CHANNEL ASSIGNMENT ALGORITHM WITH POWER-CONTROL

Local autonomous dynamic channel allocation (LADCA) including power control is essential to accommodating the anticipated explosion of demand for wireless. We simulate call performance for users accessing channels in a regular cellular array with a base located at the center of each hexagon, The computer model includes stochastic channel demand and a propagation environment characterized by attenuation with distance as well as shadow fading, Our study of LADCA shows that distributed power control and channel access can be combined in an access management policy that achieves satisfactory system capacity and provides desired call performance, We report: LADCA/power control is observed to be stable alleviating a major concern about users unaware of the signal to interference problems their presence on a channel might cause to others, We learn that local autonomy in seeking access does not trigger catastrophic event cycles, but, there are important deleterious effects (next bullet) of a manageable kind. There can be substantial inadvertent dropping of calls in progress caused by originating calls, Despite great deference to ongoing calls it can turn out that nearly all unsuccessful calls are unintentionally dropped calls not blocked calls, Also, during time of high demand, oncoming calls probing for a usable channel can be quite disruptive of channel quality even for those calls that are not dropped, An adequate number of channels appropriately limits these effects, We suggest that in future studies performance criteria include a limit on call dropping along with one on call blocking. Modeling user time dynamics is essential, To neglect the dynamics of using, probing and switching channels and to instead represent call acceptance or rejection as instantaneous, is much too optimistic, One misses inadvertent call dropping and obtains unreliable estimates of the probability of an unsuccessful call under a specified load, In a 36 channel example, when the system is loaded so that an instantaneous model gives that 1% of the calls are unsuccessful, if we include time dynamics, we get that 7% are unsuccessful. LADCA contrasts very favorably with fixed channel allocation (FCA) in a comparative example, In the example, at a traffic load at which LADCA has an unsuccessful call probability of 1%, FCA has an unacceptable unsuccessful call probability of 15%.