Title: Comprehending the Effects of Carrier Sensing on Interference in Wireless Mesh Networks
Speaker: Sung-Ju Lee (HP Lab)
Date: 12. 21 (Fri) 1:30pm

In wireless networks where communications are made over a shared medium, interference is the main obstacle in providing high capacity. In multi-hop networks such as wireless mesh networks, due to the hidden terminal problem, limiting the effects of interference is a key in achieving high performance... We study interference by investigating its relation with carrier sensing. We analyze their relation over two wireless links and measure the impact of these relations on link capacity using our wireless network testbed. We show that asymmetric carrier sensing and/or interference relations occur frequently and investigate their impact on the performance degradation and unfairness in channel access. We then propose RBP (RSS Based Prediction) algorithm that predicts the goodput of each wireless link pair in the network. With a measurement overhead that increases only linearly with the number of wireless nodes, RBP estimates the flow goodputs based on the carrier sensing/interference relation between the flows. The accuracy of RBP is evaluated on our  802.11a wireless mesh network testbed.


Bio:
Sung-Ju Lee is a senior research scientist at the Mobile & Media Systems Lab (MMSL) of HP Labs. S.-J. received his Ph.D. in Computer Science from the University of California, Los Angeles (UCLA) . S.-J. published over 60 papers in the field of computer networks. He serves as a technical program committee member of various prestigious networking related conferences. He is on the steering committee of IEEE SECON and ACM WMASH. He is a senior member of IEEE and a  senior member of ACM. His research interests include computer networks, mobile networking and computing, wireless mesh and ad hoc networks, wireless LANs, overlay networks, media over networks, and large scale service infrastructure networks.