Minimizing Maximum Response Time and Delay Factor in Broadcast Scheduling

We consider online algorithms for pull-based broadcast scheduling. In this setting there are n pages of information at a server and requests for pages arrive online. When the server serves (broadcasts) a page p, all outstanding requests for that page are satisfied. We study two related metrics, namely maximum response time (waiting time) and maximum delay-factor and their weighted versions. We obtain the following results in the worst-case online competitive model. • We show that FIFO (first-in first-out) is 2-competitive even when the page sizes are different. Previously this was known only for unit-sized pages [10] via a delicate argument. Our proof differs from [10] and is perhaps more intuitive. • We give an online algorithm for maximum delay-factor that is O(1/ 2 )-competitive with (1 + )speed for unit-sized pages and with (2 + )-speed for different sized pages. This improves on the algorithm in [12] which required (2+ )-speed and (4+ )-speed respectively. In addition we s...

• Type: Conference
• Year: 2009
• Where: ESA
• Authors: Chandra Chekuri, Sungjin Im, Benjamin Moseley
• Keywords: Algorithm, Algorithms, ESA 2009, Maximum Delay-factor, Pages