Frequency reuse and distributed dynamic channel assignment in microcellular systems

In this paper the frequency reuse problem in microcellular systems is studied. It is shown that due to the particular propagation conditions in microcellular environments, the frequency reuse pattern can tolerate one or more violations. Taking into account the possibility of admitting one violation to the reuse pattern, a new concept of available carrier with violation (ACV) is developed. This concept of ACV allows to use carriers with at most one violation to the reuse pattern (VRP), under the restriction that both cells using simultaneously the same carrier must be the bound cells of their interference neighborhoods. The effect on the outage probability of using carriers with one VRP can be tolerated, because the decrease of SIR is moderate, and with an specially designed carrier acquisition and release policies, the probability that a carrier be used with VRP is less than 5% for all the range of offered traffic simulated. The concept of ACV is introduced in two distributed dynamic channel assignment (DDCA) schemes, and simulation results show that these new DDCA with VRP schemes overcome the performance of the maximum packing (MP) algorithm, without the need of centralized coordination and global rearrangements