A New Metric for Evaluating the Throughput of HEW Date: 2014-03-18 Authors: Yunzhou Li, Tsinghua Univ.
Background Yunzhou Li, Tsinghua Univ.
Inefficiencies of Current WLAN • Assume all APs are blind, in other words, they know know nothing about STAs. Yunzhou Li, Tsinghua Univ.
Inefficiencies of Current WLAN • Notorious Exposed Node Problem: Yunzhou Li, Tsinghua Univ.
Inefficiencies of Current WLAN • MAC and PHY layers are blind to their upper layers. Traffic Properties Yunzhou Li, Tsinghua Univ.
HEW with Intelligence Yunzhou Li, Tsinghua Univ.
Acquire Prior Knowledge of STAs STAs 1) often stay at some places for a long time; 2) try to access or once connected to different APs Therefore: APs can • learn some prior knowledge of STAs based on the previous measurements; • adjust transmission modes to reach High Efficiency. Yunzhou Li, Tsinghua Univ.
Key Idea • Besides the traditional per-BSS and per-STA throughput, We suggests a new metric named as throughput with learned knowledge. • large-scale channel state information (CSI); • positions of STAs relative to the APs; • statistical properties of different kinds of traffics (e.g., video and voice); Yunzhou Li, Tsinghua Univ.
Large-scale CSI for Improving Efficiency • Full CSI are hard to be acquired by APs, because Channel is varying; Every AP can only estimate the CSIs of its own STAs. • But, large-scale fading coefficients (i.e. large-scale CSI) can be obtained easily, because they could keep constant for a long time; STAs could have connected to different APspreviously. Yunzhou Li, Tsinghua Univ.
Large-scale CSI for Improving Efficiency . Power Allocation among APs based on Large-scale CSI Virtual MIMO in Multi-Cell Distributed Antenna Systems: Coordinated Transmissions with Large-Scale CSIT, JSAC 2013 Yunzhou Li, Tsinghua Univ.
Spatial Information for Improving Efficiency Solving the Exposed Node Problem: Make AP1 and AP2 know the Spatial Positions of STA1 and STA2 Yunzhou Li, Tsinghua Univ.
Traffic Properties for Improving Efficiency • Cross-layer Design. Traffic Properties (time sensitive or not, Error sensitive or not, etc.) Yunzhou Li, Tsinghua Univ.
Traffic Properties for Improving Efficiency • Similar as WiFox, StreamBoost, WLAN could be optimized based on the statistical characteristics of data-traffics.  http://www.slashgear.com/wifox-boosts-wifi-by-700-using-wireless-traffic-cop-15257159/  http://ces.cnet.com/8301-34439_1-57561919/qualcomm-to-demo-first-streamboost-wi-fi-routers-at-ces-2013/ Yunzhou Li, Tsinghua Univ.
Proposal • Evaluate the throughput of HEW under some important prior knowledge of STAs; Yunzhou Li, Tsinghua Univ.
Summary • Some prior knowledge of STAs could be useful for improving the efficiency of HEW. They can be learnt by APs when APs are communicating with STAs. • Throughput of HEW should be re-evaluated under the prior knowledge of STAs. Yunzhou Li, Tsinghua Univ.