Packet Error and Frame Rate Controls for Real Time Video Stream over Wireless LANs
ICDCSW '03 Proceedings of the 23rd International Conference on Distributed Computing Systems
AFEC: An Adaptive Forward Error Correction Protocol for End-to-End Transport of Real-Time Traffic
IC3N '98 Proceedings of the International Conference on Computer Communications and Networks
IEEE Transactions on Mobile Computing
Multicast in 802.11 WLANs: an experimental study
Proceedings of the 9th ACM international symposium on Modeling analysis and simulation of wireless and mobile systems
Adaptive FEC for 802.11 burst losses reduction
MobiMedia '06 Proceedings of the 2nd international conference on Mobile multimedia communications
WOWMOM '08 Proceedings of the 2008 International Symposium on a World of Wireless, Mobile and Multimedia Networks
Wireless multimedia delivery over 802.11e with cross-layer optimization techniques
Multimedia Tools and Applications
QoS provisioning for large-scale multi-ap WLANs
Ad Hoc Networks
Design and Implementation of DMBonIP Gateway to Provide Internet Based DMB Service
IEEE Transactions on Consumer Electronics
Performance analysis of the IEEE 802.11 distributed coordination function
IEEE Journal on Selected Areas in Communications
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A Wi-Fi broadcasting system is a kind of Mobile-TV system that transmits multimedia content over Wi-Fi networks. The specialty of the system is that it takes advantage of broadcast packets for streaming to be scalable to the number of users. However, the loss rate of broadcast packets is much higher than that of unicast ones because MAC layer retransmission is not applied on broadcast packets. To recover lost packets, a packet level Forward Error Correction (FEC) scheme is usually used in Wi-Fi broadcasting systems. But it introduces additional transmission overhead, which is usually proportional to the packet loss rate. So it is important to reduce the packet loss rate to build an efficient and reliable Wi-Fi broadcasting system. While past studies have considered only single-AP systems, our study focuses on a multi-AP system which is designed to cover a much larger area. We found a specific packet collision problem that increases packet loss rate significantly in a multi-AP system. It is caused by the simultaneous arrival and transmission of a broadcast packet at and by APs. We identify two scenarios of the collision that depend on the channel state at the time of packet arrival. We propose two collision avoidance methods to handle these scenarios: Broadcast Packet Scheduling Method (BPSM) and Adaptive Contention Window-Sizing Method(ACWSM). We implement both methods in our multi-AP Wi-Fi broadcasting system and verify their effectiveness through experiments.