We investigate the multicast of layered multimedia content in single hop cognitive radio (CR) networks and ways of improving the subscriber utility. The proposed unified opportunistic scheduling (UOS) aggressively utilizes diversity potential present in CR by exploiting two types of multiuser diversity (MUD), one between multicast groups and another between data stream subscribers in a group. As a result, the resource usage efficiency is significantly increased, and better utility can be achieved. According to derived effective average subscriber throughput under unified MUD, a scheduling algorithm is designed to approach the theoretical throughput improvement. We specifically introduce controlled competition between multicast groups to balance the increasing resource efficiency and the risk of overstretching the limited available spectrum. The algorithm combines prioritization, rateless coding, and data fragmentation to inherently cope with dynamic spectrum availability in CR. The presented simulation results show improved performance in various situations in comparison to other schemes not taking full advantage of the present MUD potential.

Abstract With the growth of multimedia traffic over mobile networks, multicast becomes one of more effective transmission approaches to be widely considered. The Multimedia Broadcast multicast service Single Frequency Network (MBSFN) has been introduced for long term evolution to improve signal‐to‐interference‐plus‐noise ratio at the cell edges, while selecting efficient modulation and coding schemes (MCS) for transmission is still an open issue. Unlike existing solutions in literature, the opportunistic multicasting concept is adopted in this work to aggressively enhance the spectrum efficiency (SE) of single frequency networks. Based on the derived model of effective SE in extended MCS adaptation intervals, we propose a statistical feedback‐based approach to achieve opportunistic multicasting in MBSFN. The algorithm carefully selects the MCS complying with the adaptation need for channel quality changes and enabling high bottleneck user SE under reduced feedbacks. Comparing with other schemes for a single stream setup, the simulations show up to 340% higher SE over non‐opportunistic method and 25% over the second best method maximizing the average SE. The number of successfully transmitted streams in a multi‐stream scenario increased by 250% over the non‐opportunistic approach and 40% over the average SE maximizing approach. Copyright © 2016 John Wiley & Sons, Ltd.

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) an opportunistic multicasting framework, based on rateless forward error correction (FEC) codes, 2) a mechanism for adaptation of data fragment size to improve transmission efficiency, 3) a joint secondary channel (SC) and video data selection algorithm. By adapting fragment size, tracking video group receiving rate, and adapting transmission parameters, we are able to realize the opportunistic multicasting advantage in a challenging CR environment. The proposed overall SC and video data selection algorithm finds the best rateless FEC code length, physical layer modulation and coding schemes (MCS), fragment size and SC combination to increase the effective throughput and heuristically reach maximum system utility. Favorable results comparing to other algorithms showcase the improved performance.

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.