WLC25-2: Channel Allocation Algorithms for Three-tier Wireless Local Loops

A three-tier wireless local loop (WLL) extends the single-tier or two-tier WLL, and it is capable of accommodating more subscribers. This paper presents and analyzes channel allocation algorithms for a three-tier WLL. These algorithms include no repacking (NR), always repacking (AR), Repacking on Demand - Random (RoDR), Repacking on Demand - Least Load (RoDL), and Repacking on Demand - Subscriber Terminal (RoDST), depending on how repacking candidates are handled. Blocking probability and handoff probability are compared among all these channel assignment algorithms by simulations. It is shown that given the same set of simulation parameters, NR has the highest blocking probability, AR has the lowest blocking probability, and RoD has a blocking probability that falls in between. Compared with NR, both AR and RoD reduce the block probability at cost of a high handoff probability. Among RoDR, RoDL, and RoDST, RoDST has the lowest blocking probability but the highest handoff probability.