Online Bandwidth Allocation

TL;DR

This paper presents an online algorithm for bandwidth allocation in wireless networks that minimizes reallocations, achieving a constant competitive ratio, and extends the analysis to memory management systems.

Contribution

It introduces an O(1)-competitive online algorithm for subtree reallocations in a binary tree model, improving understanding of resource reallocation efficiency.

Findings

Achieves O(1) competitive ratio for online subtree allocation

Provides an amortized analysis for memory management applications

Improves bounds on reallocations in resource allocation problems

Abstract

The paper investigates a version of the resource allocation problem arising in the wireless networking, namely in the OVSF code reallocation process. In this setting a complete binary tree of a given height $n$ is considered, together with a sequence of requests which have to be served in an online manner. The requests are of two types: an insertion request requires to allocate a complete subtree of a given height, and a deletion request frees a given allocated subtree. In order to serve an insertion request it might be necessary to move some already allocated subtrees to other locations in order to free a large enough subtree. We are interested in the worst case average number of such reallocations needed to serve a request. It was proved in previous work that the competitive ratio of the optimal online algorithm solving this problem is between 1.5 and O(n). We partially answer the question about its exact value by giving an O(1)-competitive online algorithm. Same model has been used in the context of memory management systems, and analyzed for the number of reallocations needed to serve a request in the worst case. In this setting, our result is a corresponding amortized analysis.