Statistically optimized minislot allocation for initial and collision resolution in hybrid fiber coaxial networks

In a two-way hybrid fiber coaxial (HFC) network, the headend broadcasts in downstream channels, whereas all stations share the upstream channels. Hence, collision occurs when multiple stations send their bandwidth requests in a minislot. The headend determines how many minislots to allocate to manage collisions. This paper proposes a minislot allocation (SOMA) algorithm to optimize minislot throughput based on statistical estimation. A time proportional scheme is adopted to estimate the number of new requests in the initial resolution process. In addition, the number of retry requests in the collision resolution process is estimated by looking up a predetermined table of the most likely number of requests (MLR). In addition, SOMA is modified to reduce the request access delay by relaxing its allocation policy in a specific situation. We use a self-similar traffic model for simulation and analysis to compare SOMA with the optimal bound and the 3-ary tree algorithm.