Joint opportunistic spectrum access and scheduling for layered multicasting over cognitive radio networks

Abstract

Cognitive radio (CR) represents an exciting new paradigm on spectrum utilization and potentially more bandwidth for exploding multimedia traffic. We focus on the layer encoded video multicast problem over CR and contribute 1) a quality based ranking in opportunistic spectrum access (OSA) for sub-channel selection, and 2) opportunistic layered multicasting (OLM) inspired scheduling designed particularly for CR networks. The 2-step ranking in OSA takes outcomes of periodic sensing and prediction to expand the system-wide throughput while keeping collision rates acceptable. By tracking group receiving rate across CR sub-channels and data expiration time, we are able to realize the OLM advantage under much more challenging CR environments. The overall joint opportunistic spectrum access and scheduling (OSAS) algorithm finds precise transmission parameters to heuristically reach maximum system utility. Favorable results comparing OSAS with not fully opportunistic methods demonstrate OSAS to be the best performing one.

Rateless code based opportunistic multicasting over cognitive radio networks

“…The theoretical advantages of opportunistic over non-opportunistic multicasting are shown and compared in [3], [4]. In [6], the scheduling order of video layers are jointly ranked considering the CR network environment.…”

“…An investigation of the opportunistic multicasting concept in CR is done in [6]. To further improve the algorithm performance, we jointly optimize the selection of video data to be transmitted and SCs, which are going to be used for these transmissions.…”

“…All schemes use OSA, as presented in [5], [6], as a SC selection method. OSAS [6] uses dynamic block-based FEC protection, with a margin factor f m = 0.7. Non-opportunistic (Nonopp.)…”

“…Further in [6], with the use of a quality based ranking in OSA for secondary channel (SC) selection and an OLM inspired opportunistic scheduling, the aforementioned mechanisms were adapted for a CR environment. The use of rateless FEC for layered video transmission in CR is investigated in [7], where the trade-offs between link reliability, spectral efficiency and coding overhead are studied.…”

Atomic fragmentation for efficient opportunistic multicasting over cognitive radio networks

“…In this section, we compare the presented zero waste scheduling (ZWS) scheme to the RCOM scheme [3], which selects fragment sizes from the MCS dependent tile capacities, in order to minimize waste and cross tile dependency and OSAS, as presented in [5].…”