WinlabMadwifi -> Pipeline MAC paper Discussion Paper Title: = Cooperative Scheduling Via Pipelining in 802.11 Wireless Networks = Download [http://www.sigcomm.org/sigcomm2005/paper-KomRam.pdf pdf] == Motivation == * Per packet Micro-scheduling need firmware/hardware(MAC) upgrade * Macro-scheduling could be done in multiple packet basis periodically, e.g 10ms. * Cooperative scheduling extensions can be supported using a new layer on top of the existing MAC layer. == Features of Scheme == * each node conducts "global scheduling" based on "load information" of all other nodes. * the global scheduling determines a TDMA-like slot/bandwidth allocation * 3 stages, 2 1/2 pipelining: * Estimation -- load exchange -- scheduling * equivalent to'' predict -- signaling -- access'' * Kernel code modification * packet_tx * packet_rx * stop_queue * wake_queue == Diagrams == [[Image(pipelinefig1.png)]] Figure 1: 802.11 extension layer architecture [[Image(pipelinefig2.png)]] Figure 2:2.5-stage pipeline architecture. Each pipeline stage is equal in duration, but estimation stage and load exchange stage for a given cycle overlap with each other. == Experiment Evaluation == using 2 nodes and 1 AP, configure 1 node to have twice bandwidth as another node (interferer/competitor) == Weakness == * a solution for IEEE 802.11 Wireless LAN, not a solution for multi-hop * no solution for signalling loss, wrong scheduling automatically fades out in next cycle. * rely on AP's beacon to sync all nodes. * very simple experiment scenario and incomplete results.